1
2 /* pngvalid.c - validate libpng by constructing then reading png files.
3 *
4 * Last changed in libpng 1.6.24 [August 4, 2016]
5 * Copyright (c) 2014-2016 Glenn Randers-Pehrson
6 * Written by John Cunningham Bowler
7 *
8 * This code is released under the libpng license.
9 * For conditions of distribution and use, see the disclaimer
10 * and license in png.h
11 *
12 * NOTES:
13 * This is a C program that is intended to be linked against libpng. It
14 * generates bitmaps internally, stores them as PNG files (using the
15 * sequential write code) then reads them back (using the sequential
16 * read code) and validates that the result has the correct data.
17 *
18 * The program can be modified and extended to test the correctness of
19 * transformations performed by libpng.
20 */
21
22 #define _POSIX_SOURCE 1
23 #define _ISOC99_SOURCE 1 /* For floating point */
24 #define _GNU_SOURCE 1 /* For the floating point exception extension */
25
26 #include <signal.h>
27 #include <stdio.h>
28
29 #if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
30 # include <config.h>
31 #endif
32
33 #ifdef HAVE_FEENABLEEXCEPT /* from config.h, if included */
34 # include <fenv.h>
35 #endif
36
37 #ifndef FE_DIVBYZERO
38 # define FE_DIVBYZERO 0
39 #endif
40 #ifndef FE_INVALID
41 # define FE_INVALID 0
42 #endif
43 #ifndef FE_OVERFLOW
44 # define FE_OVERFLOW 0
45 #endif
46
47 /* Define the following to use this test against your installed libpng, rather
48 * than the one being built here:
49 */
50 #ifdef PNG_FREESTANDING_TESTS
51 # include <png.h>
52 #else
53 # include "../../png.h"
54 #endif
55
56 #ifdef PNG_ZLIB_HEADER
57 # include PNG_ZLIB_HEADER
58 #else
59 # include <zlib.h> /* For crc32 */
60 #endif
61
62 /* 1.6.1 added support for the configure test harness, which uses 77 to indicate
63 * a skipped test, in earlier versions we need to succeed on a skipped test, so:
64 */
65 #if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H)
66 # define SKIP 77
67 #else
68 # define SKIP 0
69 #endif
70
71 /* pngvalid requires write support and one of the fixed or floating point APIs.
72 */
73 #if defined(PNG_WRITE_SUPPORTED) &&\
74 (defined(PNG_FIXED_POINT_SUPPORTED) || defined(PNG_FLOATING_POINT_SUPPORTED))
75
76 #if PNG_LIBPNG_VER < 10500
77 /* This deliberately lacks the const. */
78 typedef png_byte *png_const_bytep;
79
80 /* This is copied from 1.5.1 png.h: */
81 #define PNG_INTERLACE_ADAM7_PASSES 7
82 #define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
83 #define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
84 #define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
85 #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
86 #define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
87 -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
88 #define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
89 -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
90 #define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
91 (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
92 #define PNG_COL_FROM_PASS_COL(xIn, pass) \
93 (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
94 #define PNG_PASS_MASK(pass,off) ( \
95 ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
96 ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
97 #define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
98 ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
99 #define PNG_COL_IN_INTERLACE_PASS(x, pass) \
100 ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
101
102 /* These are needed too for the default build: */
103 #define PNG_WRITE_16BIT_SUPPORTED
104 #define PNG_READ_16BIT_SUPPORTED
105
106 /* This comes from pnglibconf.h afer 1.5: */
107 #define PNG_FP_1 100000
108 #define PNG_GAMMA_THRESHOLD_FIXED\
109 ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
110 #endif
111
112 #if PNG_LIBPNG_VER < 10600
113 /* 1.6.0 constifies many APIs, the following exists to allow pngvalid to be
114 * compiled against earlier versions.
115 */
116 # define png_const_structp png_structp
117 #endif
118
119 #ifndef RELEASE_BUILD
120 /* RELEASE_BUILD is true for releases and release candidates: */
121 # define RELEASE_BUILD (PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC)
122 #endif
123 #if RELEASE_BUILD
124 # define debugonly(something)
125 #else /* !RELEASE_BUILD */
126 # define debugonly(something) something
127 #endif /* !RELEASE_BUILD */
128
129 #include <float.h> /* For floating point constants */
130 #include <stdlib.h> /* For malloc */
131 #include <string.h> /* For memcpy, memset */
132 #include <math.h> /* For floor */
133
134 /* Convenience macros. */
135 #define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
136 #define CHUNK_IHDR CHUNK(73,72,68,82)
137 #define CHUNK_PLTE CHUNK(80,76,84,69)
138 #define CHUNK_IDAT CHUNK(73,68,65,84)
139 #define CHUNK_IEND CHUNK(73,69,78,68)
140 #define CHUNK_cHRM CHUNK(99,72,82,77)
141 #define CHUNK_gAMA CHUNK(103,65,77,65)
142 #define CHUNK_sBIT CHUNK(115,66,73,84)
143 #define CHUNK_sRGB CHUNK(115,82,71,66)
144
145 /* Unused formal parameter errors are removed using the following macro which is
146 * expected to have no bad effects on performance.
147 */
148 #ifndef UNUSED
149 # if defined(__GNUC__) || defined(_MSC_VER)
150 # define UNUSED(param) (void)param;
151 # else
152 # define UNUSED(param)
153 # endif
154 #endif
155
156 /***************************** EXCEPTION HANDLING *****************************/
157 #ifdef PNG_FREESTANDING_TESTS
158 # include <cexcept.h>
159 #else
160 # include "../visupng/cexcept.h"
161 #endif
162
163 #ifdef __cplusplus
164 # define this not_the_cpp_this
165 # define new not_the_cpp_new
166 # define voidcast(type, value) static_cast<type>(value)
167 #else
168 # define voidcast(type, value) (value)
169 #endif /* __cplusplus */
170
171 struct png_store;
172 define_exception_type(struct png_store*);
173
174 /* The following are macros to reduce typing everywhere where the well known
175 * name 'the_exception_context' must be defined.
176 */
177 #define anon_context(ps) struct exception_context *the_exception_context = \
178 &(ps)->exception_context
179 #define context(ps,fault) anon_context(ps); png_store *fault
180
181 /* This macro returns the number of elements in an array as an (unsigned int),
182 * it is necessary to avoid the inability of certain versions of GCC to use
183 * the value of a compile-time constant when performing range checks. It must
184 * be passed an array name.
185 */
186 #define ARRAY_SIZE(a) ((unsigned int)((sizeof (a))/(sizeof (a)[0])))
187
188 /* GCC BUG 66447 (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66447) requires
189 * some broken GCC versions to be fixed up to avoid invalid whining about auto
190 * variables that are *not* changed within the scope of a setjmp being changed.
191 *
192 * Feel free to extend the list of broken versions.
193 */
194 #define is_gnu(major,minor)\
195 (defined __GNUC__) && __GNUC__ == (major) && __GNUC_MINOR__ == (minor)
196 #define is_gnu_patch(major,minor,patch)\
197 is_gnu(major,minor) && __GNUC_PATCHLEVEL__ == 0
198 /* For the moment just do it always; all versions of GCC seem to be broken: */
199 #ifdef __GNUC__
200 const void * volatile make_volatile_for_gnu;
201 # define gnu_volatile(x) make_volatile_for_gnu = &x;
202 #else /* !GNUC broken versions */
203 # define gnu_volatile(x)
204 #endif /* !GNUC broken versions */
205
206 /******************************* UTILITIES ************************************/
207 /* Error handling is particularly problematic in production code - error
208 * handlers often themselves have bugs which lead to programs that detect
209 * minor errors crashing. The following functions deal with one very
210 * common class of errors in error handlers - attempting to format error or
211 * warning messages into buffers that are too small.
212 */
safecat(char * buffer,size_t bufsize,size_t pos,const char * cat)213 static size_t safecat(char *buffer, size_t bufsize, size_t pos,
214 const char *cat)
215 {
216 while (pos < bufsize && cat != NULL && *cat != 0)
217 buffer[pos++] = *cat++;
218
219 if (pos >= bufsize)
220 pos = bufsize-1;
221
222 buffer[pos] = 0;
223 return pos;
224 }
225
safecatn(char * buffer,size_t bufsize,size_t pos,int n)226 static size_t safecatn(char *buffer, size_t bufsize, size_t pos, int n)
227 {
228 char number[64];
229 sprintf(number, "%d", n);
230 return safecat(buffer, bufsize, pos, number);
231 }
232
233 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
safecatd(char * buffer,size_t bufsize,size_t pos,double d,int precision)234 static size_t safecatd(char *buffer, size_t bufsize, size_t pos, double d,
235 int precision)
236 {
237 char number[64];
238 sprintf(number, "%.*f", precision, d);
239 return safecat(buffer, bufsize, pos, number);
240 }
241 #endif
242
243 static const char invalid[] = "invalid";
244 static const char sep[] = ": ";
245
246 static const char *colour_types[8] =
247 {
248 "grayscale", invalid, "truecolour", "indexed-colour",
249 "grayscale with alpha", invalid, "truecolour with alpha", invalid
250 };
251
252 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
253 /* Convert a double precision value to fixed point. */
254 static png_fixed_point
fix(double d)255 fix(double d)
256 {
257 d = floor(d * PNG_FP_1 + .5);
258 return (png_fixed_point)d;
259 }
260 #endif /* PNG_READ_SUPPORTED */
261
262 /* Generate random bytes. This uses a boring repeatable algorithm and it
263 * is implemented here so that it gives the same set of numbers on every
264 * architecture. It's a linear congruential generator (Knuth or Sedgewick
265 * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
266 * Hill, "The Art of Electronics" (Pseudo-Random Bit Sequences and Noise
267 * Generation.)
268 */
269 static void
make_random_bytes(png_uint_32 * seed,void * pv,size_t size)270 make_random_bytes(png_uint_32* seed, void* pv, size_t size)
271 {
272 png_uint_32 u0 = seed[0], u1 = seed[1];
273 png_bytep bytes = voidcast(png_bytep, pv);
274
275 /* There are thirty three bits, the next bit in the sequence is bit-33 XOR
276 * bit-20. The top 1 bit is in u1, the bottom 32 are in u0.
277 */
278 size_t i;
279 for (i=0; i<size; ++i)
280 {
281 /* First generate 8 new bits then shift them in at the end. */
282 png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
283 u1 <<= 8;
284 u1 |= u0 >> 24;
285 u0 <<= 8;
286 u0 |= u;
287 *bytes++ = (png_byte)u;
288 }
289
290 seed[0] = u0;
291 seed[1] = u1;
292 }
293
294 static void
make_four_random_bytes(png_uint_32 * seed,png_bytep bytes)295 make_four_random_bytes(png_uint_32* seed, png_bytep bytes)
296 {
297 make_random_bytes(seed, bytes, 4);
298 }
299
300 #if defined PNG_READ_SUPPORTED || defined PNG_WRITE_tRNS_SUPPORTED ||\
301 defined PNG_WRITE_FILTER_SUPPORTED
302 static void
randomize(void * pv,size_t size)303 randomize(void *pv, size_t size)
304 {
305 static png_uint_32 random_seed[2] = {0x56789abc, 0xd};
306 make_random_bytes(random_seed, pv, size);
307 }
308
309 #define R8(this) randomize(&(this), sizeof (this))
310
311 #ifdef PNG_READ_SUPPORTED
312 static png_byte
random_byte(void)313 random_byte(void)
314 {
315 unsigned char b1[1];
316 randomize(b1, sizeof b1);
317 return b1[0];
318 }
319 #endif /* READ */
320
321 static png_uint_16
random_u16(void)322 random_u16(void)
323 {
324 unsigned char b2[2];
325 randomize(b2, sizeof b2);
326 return png_get_uint_16(b2);
327 }
328
329 #if defined PNG_READ_RGB_TO_GRAY_SUPPORTED ||\
330 defined PNG_READ_FILLER_SUPPORTED
331 static png_uint_32
random_u32(void)332 random_u32(void)
333 {
334 unsigned char b4[4];
335 randomize(b4, sizeof b4);
336 return png_get_uint_32(b4);
337 }
338 #endif /* READ_FILLER || READ_RGB_TO_GRAY */
339
340 #endif /* READ || WRITE_tRNS || WRITE_FILTER */
341
342 #if defined PNG_READ_TRANSFORMS_SUPPORTED ||\
343 defined PNG_WRITE_FILTER_SUPPORTED
344 static unsigned int
random_mod(unsigned int max)345 random_mod(unsigned int max)
346 {
347 return random_u16() % max; /* 0 .. max-1 */
348 }
349 #endif /* READ_TRANSFORMS || WRITE_FILTER */
350
351 #if (defined PNG_READ_RGB_TO_GRAY_SUPPORTED) ||\
352 (defined PNG_READ_FILLER_SUPPORTED)
353 static int
random_choice(void)354 random_choice(void)
355 {
356 return random_byte() & 1;
357 }
358 #endif /* READ_RGB_TO_GRAY || READ_FILLER */
359
360 /* A numeric ID based on PNG file characteristics. The 'do_interlace' field
361 * simply records whether pngvalid did the interlace itself or whether it
362 * was done by libpng. Width and height must be less than 256. 'palette' is an
363 * index of the palette to use for formats with a palette otherwise a boolean
364 * indicating if a tRNS chunk was generated.
365 */
366 #define FILEID(col, depth, palette, interlace, width, height, do_interlace) \
367 ((png_uint_32)((col) + ((depth)<<3) + ((palette)<<8) + ((interlace)<<13) + \
368 (((do_interlace)!=0)<<15) + ((width)<<16) + ((height)<<24)))
369
370 #define COL_FROM_ID(id) ((png_byte)((id)& 0x7U))
371 #define DEPTH_FROM_ID(id) ((png_byte)(((id) >> 3) & 0x1fU))
372 #define PALETTE_FROM_ID(id) (((id) >> 8) & 0x1f)
373 #define INTERLACE_FROM_ID(id) ((png_byte)(((id) >> 13) & 0x3))
374 #define DO_INTERLACE_FROM_ID(id) ((int)(((id)>>15) & 1))
375 #define WIDTH_FROM_ID(id) (((id)>>16) & 0xff)
376 #define HEIGHT_FROM_ID(id) (((id)>>24) & 0xff)
377
378 /* Utility to construct a standard name for a standard image. */
379 static size_t
standard_name(char * buffer,size_t bufsize,size_t pos,png_byte colour_type,int bit_depth,unsigned int npalette,int interlace_type,png_uint_32 w,png_uint_32 h,int do_interlace)380 standard_name(char *buffer, size_t bufsize, size_t pos, png_byte colour_type,
381 int bit_depth, unsigned int npalette, int interlace_type,
382 png_uint_32 w, png_uint_32 h, int do_interlace)
383 {
384 pos = safecat(buffer, bufsize, pos, colour_types[colour_type]);
385 if (colour_type == 3) /* must have a palette */
386 {
387 pos = safecat(buffer, bufsize, pos, "[");
388 pos = safecatn(buffer, bufsize, pos, npalette);
389 pos = safecat(buffer, bufsize, pos, "]");
390 }
391
392 else if (npalette != 0)
393 pos = safecat(buffer, bufsize, pos, "+tRNS");
394
395 pos = safecat(buffer, bufsize, pos, " ");
396 pos = safecatn(buffer, bufsize, pos, bit_depth);
397 pos = safecat(buffer, bufsize, pos, " bit");
398
399 if (interlace_type != PNG_INTERLACE_NONE)
400 {
401 pos = safecat(buffer, bufsize, pos, " interlaced");
402 if (do_interlace)
403 pos = safecat(buffer, bufsize, pos, "(pngvalid)");
404 else
405 pos = safecat(buffer, bufsize, pos, "(libpng)");
406 }
407
408 if (w > 0 || h > 0)
409 {
410 pos = safecat(buffer, bufsize, pos, " ");
411 pos = safecatn(buffer, bufsize, pos, w);
412 pos = safecat(buffer, bufsize, pos, "x");
413 pos = safecatn(buffer, bufsize, pos, h);
414 }
415
416 return pos;
417 }
418
419 static size_t
standard_name_from_id(char * buffer,size_t bufsize,size_t pos,png_uint_32 id)420 standard_name_from_id(char *buffer, size_t bufsize, size_t pos, png_uint_32 id)
421 {
422 return standard_name(buffer, bufsize, pos, COL_FROM_ID(id),
423 DEPTH_FROM_ID(id), PALETTE_FROM_ID(id), INTERLACE_FROM_ID(id),
424 WIDTH_FROM_ID(id), HEIGHT_FROM_ID(id), DO_INTERLACE_FROM_ID(id));
425 }
426
427 /* Convenience API and defines to list valid formats. Note that 16 bit read and
428 * write support is required to do 16 bit read tests (we must be able to make a
429 * 16 bit image to test!)
430 */
431 #ifdef PNG_WRITE_16BIT_SUPPORTED
432 # define WRITE_BDHI 4
433 # ifdef PNG_READ_16BIT_SUPPORTED
434 # define READ_BDHI 4
435 # define DO_16BIT
436 # endif
437 #else
438 # define WRITE_BDHI 3
439 #endif
440 #ifndef DO_16BIT
441 # define READ_BDHI 3
442 #endif
443
444 /* The following defines the number of different palettes to generate for
445 * each log bit depth of a colour type 3 standard image.
446 */
447 #define PALETTE_COUNT(bit_depth) ((bit_depth) > 4 ? 1U : 16U)
448
449 static int
next_format(png_bytep colour_type,png_bytep bit_depth,unsigned int * palette_number,int low_depth_gray,int tRNS)450 next_format(png_bytep colour_type, png_bytep bit_depth,
451 unsigned int* palette_number, int low_depth_gray, int tRNS)
452 {
453 if (*bit_depth == 0)
454 {
455 *colour_type = 0;
456 if (low_depth_gray)
457 *bit_depth = 1;
458 else
459 *bit_depth = 8;
460 *palette_number = 0;
461 return 1;
462 }
463
464 if (*colour_type < 4/*no alpha channel*/)
465 {
466 /* Add multiple palettes for colour type 3, one image with tRNS
467 * and one without for other non-alpha formats:
468 */
469 unsigned int pn = ++*palette_number;
470 png_byte ct = *colour_type;
471
472 if (((ct == 0/*GRAY*/ || ct/*RGB*/ == 2) && tRNS && pn < 2) ||
473 (ct == 3/*PALETTE*/ && pn < PALETTE_COUNT(*bit_depth)))
474 return 1;
475
476 /* No: next bit depth */
477 *palette_number = 0;
478 }
479
480 *bit_depth = (png_byte)(*bit_depth << 1);
481
482 /* Palette images are restricted to 8 bit depth */
483 if (*bit_depth <= 8
484 #ifdef DO_16BIT
485 || (*colour_type != 3 && *bit_depth <= 16)
486 #endif
487 )
488 return 1;
489
490 /* Move to the next color type, or return 0 at the end. */
491 switch (*colour_type)
492 {
493 case 0:
494 *colour_type = 2;
495 *bit_depth = 8;
496 return 1;
497
498 case 2:
499 *colour_type = 3;
500 *bit_depth = 1;
501 return 1;
502
503 case 3:
504 *colour_type = 4;
505 *bit_depth = 8;
506 return 1;
507
508 case 4:
509 *colour_type = 6;
510 *bit_depth = 8;
511 return 1;
512
513 default:
514 return 0;
515 }
516 }
517
518 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
519 static unsigned int
sample(png_const_bytep row,png_byte colour_type,png_byte bit_depth,png_uint_32 x,unsigned int sample_index,int swap16,int littleendian)520 sample(png_const_bytep row, png_byte colour_type, png_byte bit_depth,
521 png_uint_32 x, unsigned int sample_index, int swap16, int littleendian)
522 {
523 png_uint_32 bit_index, result;
524
525 /* Find a sample index for the desired sample: */
526 x *= bit_depth;
527 bit_index = x;
528
529 if ((colour_type & 1) == 0) /* !palette */
530 {
531 if (colour_type & 2)
532 bit_index *= 3;
533
534 if (colour_type & 4)
535 bit_index += x; /* Alpha channel */
536
537 /* Multiple channels; select one: */
538 if (colour_type & (2+4))
539 bit_index += sample_index * bit_depth;
540 }
541
542 /* Return the sample from the row as an integer. */
543 row += bit_index >> 3;
544 result = *row;
545
546 if (bit_depth == 8)
547 return result;
548
549 else if (bit_depth > 8)
550 {
551 if (swap16)
552 return (*++row << 8) + result;
553 else
554 return (result << 8) + *++row;
555 }
556
557 /* Less than 8 bits per sample. By default PNG has the big end of
558 * the egg on the left of the screen, but if littleendian is set
559 * then the big end is on the right.
560 */
561 bit_index &= 7;
562
563 if (!littleendian)
564 bit_index = 8-bit_index-bit_depth;
565
566 return (result >> bit_index) & ((1U<<bit_depth)-1);
567 }
568 #endif /* PNG_READ_TRANSFORMS_SUPPORTED */
569
570 /* Copy a single pixel, of a given size, from one buffer to another -
571 * while this is basically bit addressed there is an implicit assumption
572 * that pixels 8 or more bits in size are byte aligned and that pixels
573 * do not otherwise cross byte boundaries. (This is, so far as I know,
574 * universally true in bitmap computer graphics. [JCB 20101212])
575 *
576 * NOTE: The to and from buffers may be the same.
577 */
578 static void
pixel_copy(png_bytep toBuffer,png_uint_32 toIndex,png_const_bytep fromBuffer,png_uint_32 fromIndex,unsigned int pixelSize,int littleendian)579 pixel_copy(png_bytep toBuffer, png_uint_32 toIndex,
580 png_const_bytep fromBuffer, png_uint_32 fromIndex, unsigned int pixelSize,
581 int littleendian)
582 {
583 /* Assume we can multiply by 'size' without overflow because we are
584 * just working in a single buffer.
585 */
586 toIndex *= pixelSize;
587 fromIndex *= pixelSize;
588 if (pixelSize < 8) /* Sub-byte */
589 {
590 /* Mask to select the location of the copied pixel: */
591 unsigned int destMask = ((1U<<pixelSize)-1) <<
592 (littleendian ? toIndex&7 : 8-pixelSize-(toIndex&7));
593 /* The following read the entire pixels and clears the extra: */
594 unsigned int destByte = toBuffer[toIndex >> 3] & ~destMask;
595 unsigned int sourceByte = fromBuffer[fromIndex >> 3];
596
597 /* Don't rely on << or >> supporting '0' here, just in case: */
598 fromIndex &= 7;
599 if (littleendian)
600 {
601 if (fromIndex > 0) sourceByte >>= fromIndex;
602 if ((toIndex & 7) > 0) sourceByte <<= toIndex & 7;
603 }
604
605 else
606 {
607 if (fromIndex > 0) sourceByte <<= fromIndex;
608 if ((toIndex & 7) > 0) sourceByte >>= toIndex & 7;
609 }
610
611 toBuffer[toIndex >> 3] = (png_byte)(destByte | (sourceByte & destMask));
612 }
613 else /* One or more bytes */
614 memmove(toBuffer+(toIndex>>3), fromBuffer+(fromIndex>>3), pixelSize>>3);
615 }
616
617 #ifdef PNG_READ_SUPPORTED
618 /* Copy a complete row of pixels, taking into account potential partial
619 * bytes at the end.
620 */
621 static void
row_copy(png_bytep toBuffer,png_const_bytep fromBuffer,unsigned int bitWidth,int littleendian)622 row_copy(png_bytep toBuffer, png_const_bytep fromBuffer, unsigned int bitWidth,
623 int littleendian)
624 {
625 memcpy(toBuffer, fromBuffer, bitWidth >> 3);
626
627 if ((bitWidth & 7) != 0)
628 {
629 unsigned int mask;
630
631 toBuffer += bitWidth >> 3;
632 fromBuffer += bitWidth >> 3;
633 if (littleendian)
634 mask = 0xff << (bitWidth & 7);
635 else
636 mask = 0xff >> (bitWidth & 7);
637 *toBuffer = (png_byte)((*toBuffer & mask) | (*fromBuffer & ~mask));
638 }
639 }
640
641 /* Compare pixels - they are assumed to start at the first byte in the
642 * given buffers.
643 */
644 static int
pixel_cmp(png_const_bytep pa,png_const_bytep pb,png_uint_32 bit_width)645 pixel_cmp(png_const_bytep pa, png_const_bytep pb, png_uint_32 bit_width)
646 {
647 #if PNG_LIBPNG_VER < 10506
648 if (memcmp(pa, pb, bit_width>>3) == 0)
649 {
650 png_uint_32 p;
651
652 if ((bit_width & 7) == 0) return 0;
653
654 /* Ok, any differences? */
655 p = pa[bit_width >> 3];
656 p ^= pb[bit_width >> 3];
657
658 if (p == 0) return 0;
659
660 /* There are, but they may not be significant, remove the bits
661 * after the end (the low order bits in PNG.)
662 */
663 bit_width &= 7;
664 p >>= 8-bit_width;
665
666 if (p == 0) return 0;
667 }
668 #else
669 /* From libpng-1.5.6 the overwrite should be fixed, so compare the trailing
670 * bits too:
671 */
672 if (memcmp(pa, pb, (bit_width+7)>>3) == 0)
673 return 0;
674 #endif
675
676 /* Return the index of the changed byte. */
677 {
678 png_uint_32 where = 0;
679
680 while (pa[where] == pb[where]) ++where;
681 return 1+where;
682 }
683 }
684 #endif /* PNG_READ_SUPPORTED */
685
686 /*************************** BASIC PNG FILE WRITING ***************************/
687 /* A png_store takes data from the sequential writer or provides data
688 * to the sequential reader. It can also store the result of a PNG
689 * write for later retrieval.
690 */
691 #define STORE_BUFFER_SIZE 500 /* arbitrary */
692 typedef struct png_store_buffer
693 {
694 struct png_store_buffer* prev; /* NOTE: stored in reverse order */
695 png_byte buffer[STORE_BUFFER_SIZE];
696 } png_store_buffer;
697
698 #define FILE_NAME_SIZE 64
699
700 typedef struct store_palette_entry /* record of a single palette entry */
701 {
702 png_byte red;
703 png_byte green;
704 png_byte blue;
705 png_byte alpha;
706 } store_palette_entry, store_palette[256];
707
708 typedef struct png_store_file
709 {
710 struct png_store_file* next; /* as many as you like... */
711 char name[FILE_NAME_SIZE];
712 unsigned int IDAT_bits; /* Number of bits in IDAT size */
713 png_uint_32 IDAT_size; /* Total size of IDAT data */
714 png_uint_32 id; /* must be correct (see FILEID) */
715 png_size_t datacount; /* In this (the last) buffer */
716 png_store_buffer data; /* Last buffer in file */
717 int npalette; /* Number of entries in palette */
718 store_palette_entry* palette; /* May be NULL */
719 } png_store_file;
720
721 /* The following is a pool of memory allocated by a single libpng read or write
722 * operation.
723 */
724 typedef struct store_pool
725 {
726 struct png_store *store; /* Back pointer */
727 struct store_memory *list; /* List of allocated memory */
728 png_byte mark[4]; /* Before and after data */
729
730 /* Statistics for this run. */
731 png_alloc_size_t max; /* Maximum single allocation */
732 png_alloc_size_t current; /* Current allocation */
733 png_alloc_size_t limit; /* Highest current allocation */
734 png_alloc_size_t total; /* Total allocation */
735
736 /* Overall statistics (retained across successive runs). */
737 png_alloc_size_t max_max;
738 png_alloc_size_t max_limit;
739 png_alloc_size_t max_total;
740 } store_pool;
741
742 typedef struct png_store
743 {
744 /* For cexcept.h exception handling - simply store one of these;
745 * the context is a self pointer but it may point to a different
746 * png_store (in fact it never does in this program.)
747 */
748 struct exception_context
749 exception_context;
750
751 unsigned int verbose :1;
752 unsigned int treat_warnings_as_errors :1;
753 unsigned int expect_error :1;
754 unsigned int expect_warning :1;
755 unsigned int saw_warning :1;
756 unsigned int speed :1;
757 unsigned int progressive :1; /* use progressive read */
758 unsigned int validated :1; /* used as a temporary flag */
759 int nerrors;
760 int nwarnings;
761 int noptions; /* number of options below: */
762 struct {
763 unsigned char option; /* option number, 0..30 */
764 unsigned char setting; /* setting (unset,invalid,on,off) */
765 } options[16];
766 char test[128]; /* Name of test */
767 char error[256];
768
769 /* Share fields */
770 png_uint_32 chunklen; /* Length of chunk+overhead (chunkpos >= 8) */
771 png_uint_32 chunktype;/* Type of chunk (valid if chunkpos >= 4) */
772 png_uint_32 chunkpos; /* Position in chunk */
773 png_uint_32 IDAT_size;/* Accumulated IDAT size in .new */
774 unsigned int IDAT_bits;/* Cache of the file store value */
775
776 /* Read fields */
777 png_structp pread; /* Used to read a saved file */
778 png_infop piread;
779 png_store_file* current; /* Set when reading */
780 png_store_buffer* next; /* Set when reading */
781 png_size_t readpos; /* Position in *next */
782 png_byte* image; /* Buffer for reading interlaced images */
783 png_size_t cb_image; /* Size of this buffer */
784 png_size_t cb_row; /* Row size of the image(s) */
785 uLong IDAT_crc;
786 png_uint_32 IDAT_len; /* Used when re-chunking IDAT chunks */
787 png_uint_32 IDAT_pos; /* Used when re-chunking IDAT chunks */
788 png_uint_32 image_h; /* Number of rows in a single image */
789 store_pool read_memory_pool;
790
791 /* Write fields */
792 png_store_file* saved;
793 png_structp pwrite; /* Used when writing a new file */
794 png_infop piwrite;
795 png_size_t writepos; /* Position in .new */
796 char wname[FILE_NAME_SIZE];
797 png_store_buffer new; /* The end of the new PNG file being written. */
798 store_pool write_memory_pool;
799 store_palette_entry* palette;
800 int npalette;
801 } png_store;
802
803 /* Initialization and cleanup */
804 static void
store_pool_mark(png_bytep mark)805 store_pool_mark(png_bytep mark)
806 {
807 static png_uint_32 store_seed[2] = { 0x12345678, 1};
808
809 make_four_random_bytes(store_seed, mark);
810 }
811
812 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
813 /* Use this for random 32 bit values; this function makes sure the result is
814 * non-zero.
815 */
816 static png_uint_32
random_32(void)817 random_32(void)
818 {
819
820 for (;;)
821 {
822 png_byte mark[4];
823 png_uint_32 result;
824
825 store_pool_mark(mark);
826 result = png_get_uint_32(mark);
827
828 if (result != 0)
829 return result;
830 }
831 }
832 #endif /* PNG_READ_SUPPORTED */
833
834 static void
store_pool_init(png_store * ps,store_pool * pool)835 store_pool_init(png_store *ps, store_pool *pool)
836 {
837 memset(pool, 0, sizeof *pool);
838
839 pool->store = ps;
840 pool->list = NULL;
841 pool->max = pool->current = pool->limit = pool->total = 0;
842 pool->max_max = pool->max_limit = pool->max_total = 0;
843 store_pool_mark(pool->mark);
844 }
845
846 static void
store_init(png_store * ps)847 store_init(png_store* ps)
848 {
849 memset(ps, 0, sizeof *ps);
850 init_exception_context(&ps->exception_context);
851 store_pool_init(ps, &ps->read_memory_pool);
852 store_pool_init(ps, &ps->write_memory_pool);
853 ps->verbose = 0;
854 ps->treat_warnings_as_errors = 0;
855 ps->expect_error = 0;
856 ps->expect_warning = 0;
857 ps->saw_warning = 0;
858 ps->speed = 0;
859 ps->progressive = 0;
860 ps->validated = 0;
861 ps->nerrors = ps->nwarnings = 0;
862 ps->pread = NULL;
863 ps->piread = NULL;
864 ps->saved = ps->current = NULL;
865 ps->next = NULL;
866 ps->readpos = 0;
867 ps->image = NULL;
868 ps->cb_image = 0;
869 ps->cb_row = 0;
870 ps->image_h = 0;
871 ps->pwrite = NULL;
872 ps->piwrite = NULL;
873 ps->writepos = 0;
874 ps->chunkpos = 8;
875 ps->chunktype = 0;
876 ps->chunklen = 16;
877 ps->IDAT_size = 0;
878 ps->IDAT_bits = 0;
879 ps->new.prev = NULL;
880 ps->palette = NULL;
881 ps->npalette = 0;
882 ps->noptions = 0;
883 }
884
885 static void
store_freebuffer(png_store_buffer * psb)886 store_freebuffer(png_store_buffer* psb)
887 {
888 if (psb->prev)
889 {
890 store_freebuffer(psb->prev);
891 free(psb->prev);
892 psb->prev = NULL;
893 }
894 }
895
896 static void
store_freenew(png_store * ps)897 store_freenew(png_store *ps)
898 {
899 store_freebuffer(&ps->new);
900 ps->writepos = 0;
901 ps->chunkpos = 8;
902 ps->chunktype = 0;
903 ps->chunklen = 16;
904 ps->IDAT_size = 0;
905 ps->IDAT_bits = 0;
906 if (ps->palette != NULL)
907 {
908 free(ps->palette);
909 ps->palette = NULL;
910 ps->npalette = 0;
911 }
912 }
913
914 static void
store_storenew(png_store * ps)915 store_storenew(png_store *ps)
916 {
917 png_store_buffer *pb;
918
919 pb = voidcast(png_store_buffer*, malloc(sizeof *pb));
920
921 if (pb == NULL)
922 png_error(ps->pwrite, "store new: OOM");
923
924 *pb = ps->new;
925 ps->new.prev = pb;
926 ps->writepos = 0;
927 }
928
929 static void
store_freefile(png_store_file ** ppf)930 store_freefile(png_store_file **ppf)
931 {
932 if (*ppf != NULL)
933 {
934 store_freefile(&(*ppf)->next);
935
936 store_freebuffer(&(*ppf)->data);
937 (*ppf)->datacount = 0;
938 if ((*ppf)->palette != NULL)
939 {
940 free((*ppf)->palette);
941 (*ppf)->palette = NULL;
942 (*ppf)->npalette = 0;
943 }
944 free(*ppf);
945 *ppf = NULL;
946 }
947 }
948
949 static unsigned int
bits_of(png_uint_32 num)950 bits_of(png_uint_32 num)
951 {
952 /* Return the number of bits in 'num' */
953 unsigned int b = 0;
954
955 if (num & 0xffff0000U) b += 16U, num >>= 16;
956 if (num & 0xff00U) b += 8U, num >>= 8;
957 if (num & 0xf0U) b += 4U, num >>= 4;
958 if (num & 0xcU) b += 2U, num >>= 2;
959 if (num & 0x2U) ++b, num >>= 1;
960 if (num) ++b;
961
962 return b; /* 0..32 */
963 }
964
965 /* Main interface to file storeage, after writing a new PNG file (see the API
966 * below) call store_storefile to store the result with the given name and id.
967 */
968 static void
store_storefile(png_store * ps,png_uint_32 id)969 store_storefile(png_store *ps, png_uint_32 id)
970 {
971 png_store_file *pf;
972
973 if (ps->chunkpos != 0U || ps->chunktype != 0U || ps->chunklen != 0U ||
974 ps->IDAT_size == 0)
975 png_error(ps->pwrite, "storefile: incomplete write");
976
977 pf = voidcast(png_store_file*, malloc(sizeof *pf));
978 if (pf == NULL)
979 png_error(ps->pwrite, "storefile: OOM");
980 safecat(pf->name, sizeof pf->name, 0, ps->wname);
981 pf->id = id;
982 pf->data = ps->new;
983 pf->datacount = ps->writepos;
984 pf->IDAT_size = ps->IDAT_size;
985 pf->IDAT_bits = bits_of(ps->IDAT_size);
986 /* Because the IDAT always has zlib header stuff this must be true: */
987 if (pf->IDAT_bits == 0U)
988 png_error(ps->pwrite, "storefile: 0 sized IDAT");
989 ps->new.prev = NULL;
990 ps->writepos = 0;
991 ps->chunkpos = 8;
992 ps->chunktype = 0;
993 ps->chunklen = 16;
994 ps->IDAT_size = 0;
995 pf->palette = ps->palette;
996 pf->npalette = ps->npalette;
997 ps->palette = 0;
998 ps->npalette = 0;
999
1000 /* And save it. */
1001 pf->next = ps->saved;
1002 ps->saved = pf;
1003 }
1004
1005 /* Generate an error message (in the given buffer) */
1006 static size_t
store_message(png_store * ps,png_const_structp pp,char * buffer,size_t bufsize,size_t pos,const char * msg)1007 store_message(png_store *ps, png_const_structp pp, char *buffer, size_t bufsize,
1008 size_t pos, const char *msg)
1009 {
1010 if (pp != NULL && pp == ps->pread)
1011 {
1012 /* Reading a file */
1013 pos = safecat(buffer, bufsize, pos, "read: ");
1014
1015 if (ps->current != NULL)
1016 {
1017 pos = safecat(buffer, bufsize, pos, ps->current->name);
1018 pos = safecat(buffer, bufsize, pos, sep);
1019 }
1020 }
1021
1022 else if (pp != NULL && pp == ps->pwrite)
1023 {
1024 /* Writing a file */
1025 pos = safecat(buffer, bufsize, pos, "write: ");
1026 pos = safecat(buffer, bufsize, pos, ps->wname);
1027 pos = safecat(buffer, bufsize, pos, sep);
1028 }
1029
1030 else
1031 {
1032 /* Neither reading nor writing (or a memory error in struct delete) */
1033 pos = safecat(buffer, bufsize, pos, "pngvalid: ");
1034 }
1035
1036 if (ps->test[0] != 0)
1037 {
1038 pos = safecat(buffer, bufsize, pos, ps->test);
1039 pos = safecat(buffer, bufsize, pos, sep);
1040 }
1041 pos = safecat(buffer, bufsize, pos, msg);
1042 return pos;
1043 }
1044
1045 /* Verbose output to the error stream: */
1046 static void
store_verbose(png_store * ps,png_const_structp pp,png_const_charp prefix,png_const_charp message)1047 store_verbose(png_store *ps, png_const_structp pp, png_const_charp prefix,
1048 png_const_charp message)
1049 {
1050 char buffer[512];
1051
1052 if (prefix)
1053 fputs(prefix, stderr);
1054
1055 (void)store_message(ps, pp, buffer, sizeof buffer, 0, message);
1056 fputs(buffer, stderr);
1057 fputc('\n', stderr);
1058 }
1059
1060 /* Log an error or warning - the relevant count is always incremented. */
1061 static void
store_log(png_store * ps,png_const_structp pp,png_const_charp message,int is_error)1062 store_log(png_store* ps, png_const_structp pp, png_const_charp message,
1063 int is_error)
1064 {
1065 /* The warning is copied to the error buffer if there are no errors and it is
1066 * the first warning. The error is copied to the error buffer if it is the
1067 * first error (overwriting any prior warnings).
1068 */
1069 if (is_error ? (ps->nerrors)++ == 0 :
1070 (ps->nwarnings)++ == 0 && ps->nerrors == 0)
1071 store_message(ps, pp, ps->error, sizeof ps->error, 0, message);
1072
1073 if (ps->verbose)
1074 store_verbose(ps, pp, is_error ? "error: " : "warning: ", message);
1075 }
1076
1077 #ifdef PNG_READ_SUPPORTED
1078 /* Internal error function, called with a png_store but no libpng stuff. */
1079 static void
internal_error(png_store * ps,png_const_charp message)1080 internal_error(png_store *ps, png_const_charp message)
1081 {
1082 store_log(ps, NULL, message, 1 /* error */);
1083
1084 /* And finally throw an exception. */
1085 {
1086 struct exception_context *the_exception_context = &ps->exception_context;
1087 Throw ps;
1088 }
1089 }
1090 #endif /* PNG_READ_SUPPORTED */
1091
1092 /* Functions to use as PNG callbacks. */
1093 static void PNGCBAPI
store_error(png_structp ppIn,png_const_charp message)1094 store_error(png_structp ppIn, png_const_charp message) /* PNG_NORETURN */
1095 {
1096 png_const_structp pp = ppIn;
1097 png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
1098
1099 if (!ps->expect_error)
1100 store_log(ps, pp, message, 1 /* error */);
1101
1102 /* And finally throw an exception. */
1103 {
1104 struct exception_context *the_exception_context = &ps->exception_context;
1105 Throw ps;
1106 }
1107 }
1108
1109 static void PNGCBAPI
store_warning(png_structp ppIn,png_const_charp message)1110 store_warning(png_structp ppIn, png_const_charp message)
1111 {
1112 png_const_structp pp = ppIn;
1113 png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
1114
1115 if (!ps->expect_warning)
1116 store_log(ps, pp, message, 0 /* warning */);
1117 else
1118 ps->saw_warning = 1;
1119 }
1120
1121 /* These somewhat odd functions are used when reading an image to ensure that
1122 * the buffer is big enough, the png_structp is for errors.
1123 */
1124 /* Return a single row from the correct image. */
1125 static png_bytep
store_image_row(const png_store * ps,png_const_structp pp,int nImage,png_uint_32 y)1126 store_image_row(const png_store* ps, png_const_structp pp, int nImage,
1127 png_uint_32 y)
1128 {
1129 png_size_t coffset = (nImage * ps->image_h + y) * (ps->cb_row + 5) + 2;
1130
1131 if (ps->image == NULL)
1132 png_error(pp, "no allocated image");
1133
1134 if (coffset + ps->cb_row + 3 > ps->cb_image)
1135 png_error(pp, "image too small");
1136
1137 return ps->image + coffset;
1138 }
1139
1140 static void
store_image_free(png_store * ps,png_const_structp pp)1141 store_image_free(png_store *ps, png_const_structp pp)
1142 {
1143 if (ps->image != NULL)
1144 {
1145 png_bytep image = ps->image;
1146
1147 if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
1148 {
1149 if (pp != NULL)
1150 png_error(pp, "png_store image overwrite (1)");
1151 else
1152 store_log(ps, NULL, "png_store image overwrite (2)", 1);
1153 }
1154
1155 ps->image = NULL;
1156 ps->cb_image = 0;
1157 --image;
1158 free(image);
1159 }
1160 }
1161
1162 static void
store_ensure_image(png_store * ps,png_const_structp pp,int nImages,png_size_t cbRow,png_uint_32 cRows)1163 store_ensure_image(png_store *ps, png_const_structp pp, int nImages,
1164 png_size_t cbRow, png_uint_32 cRows)
1165 {
1166 png_size_t cb = nImages * cRows * (cbRow + 5);
1167
1168 if (ps->cb_image < cb)
1169 {
1170 png_bytep image;
1171
1172 store_image_free(ps, pp);
1173
1174 /* The buffer is deliberately mis-aligned. */
1175 image = voidcast(png_bytep, malloc(cb+2));
1176 if (image == NULL)
1177 {
1178 /* Called from the startup - ignore the error for the moment. */
1179 if (pp == NULL)
1180 return;
1181
1182 png_error(pp, "OOM allocating image buffer");
1183 }
1184
1185 /* These magic tags are used to detect overwrites above. */
1186 ++image;
1187 image[-1] = 0xed;
1188 image[cb] = 0xfe;
1189
1190 ps->image = image;
1191 ps->cb_image = cb;
1192 }
1193
1194 /* We have an adequate sized image; lay out the rows. There are 2 bytes at
1195 * the start and three at the end of each (this ensures that the row
1196 * alignment starts out odd - 2+1 and changes for larger images on each row.)
1197 */
1198 ps->cb_row = cbRow;
1199 ps->image_h = cRows;
1200
1201 /* For error checking, the whole buffer is set to 10110010 (0xb2 - 178).
1202 * This deliberately doesn't match the bits in the size test image which are
1203 * outside the image; these are set to 0xff (all 1). To make the row
1204 * comparison work in the 'size' test case the size rows are pre-initialized
1205 * to the same value prior to calling 'standard_row'.
1206 */
1207 memset(ps->image, 178, cb);
1208
1209 /* Then put in the marks. */
1210 while (--nImages >= 0)
1211 {
1212 png_uint_32 y;
1213
1214 for (y=0; y<cRows; ++y)
1215 {
1216 png_bytep row = store_image_row(ps, pp, nImages, y);
1217
1218 /* The markers: */
1219 row[-2] = 190;
1220 row[-1] = 239;
1221 row[cbRow] = 222;
1222 row[cbRow+1] = 173;
1223 row[cbRow+2] = 17;
1224 }
1225 }
1226 }
1227
1228 #ifdef PNG_READ_SUPPORTED
1229 static void
store_image_check(const png_store * ps,png_const_structp pp,int iImage)1230 store_image_check(const png_store* ps, png_const_structp pp, int iImage)
1231 {
1232 png_const_bytep image = ps->image;
1233
1234 if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
1235 png_error(pp, "image overwrite");
1236 else
1237 {
1238 png_size_t cbRow = ps->cb_row;
1239 png_uint_32 rows = ps->image_h;
1240
1241 image += iImage * (cbRow+5) * ps->image_h;
1242
1243 image += 2; /* skip image first row markers */
1244
1245 while (rows-- > 0)
1246 {
1247 if (image[-2] != 190 || image[-1] != 239)
1248 png_error(pp, "row start overwritten");
1249
1250 if (image[cbRow] != 222 || image[cbRow+1] != 173 ||
1251 image[cbRow+2] != 17)
1252 png_error(pp, "row end overwritten");
1253
1254 image += cbRow+5;
1255 }
1256 }
1257 }
1258 #endif /* PNG_READ_SUPPORTED */
1259
1260 static int
valid_chunktype(png_uint_32 chunktype)1261 valid_chunktype(png_uint_32 chunktype)
1262 {
1263 /* Each byte in the chunk type must be in one of the ranges 65..90, 97..122
1264 * (both inclusive), so:
1265 */
1266 unsigned int i;
1267
1268 for (i=0; i<4; ++i)
1269 {
1270 unsigned int c = chunktype & 0xffU;
1271
1272 if (!((c >= 65U && c <= 90U) || (c >= 97U && c <= 122U)))
1273 return 0;
1274
1275 chunktype >>= 8;
1276 }
1277
1278 return 1; /* It's valid */
1279 }
1280
1281 static void PNGCBAPI
store_write(png_structp ppIn,png_bytep pb,png_size_t st)1282 store_write(png_structp ppIn, png_bytep pb, png_size_t st)
1283 {
1284 png_const_structp pp = ppIn;
1285 png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
1286 size_t writepos = ps->writepos;
1287 png_uint_32 chunkpos = ps->chunkpos;
1288 png_uint_32 chunktype = ps->chunktype;
1289 png_uint_32 chunklen = ps->chunklen;
1290
1291 if (ps->pwrite != pp)
1292 png_error(pp, "store state damaged");
1293
1294 /* Technically this is legal, but in practice libpng never writes more than
1295 * the maximum chunk size at once so if it happens something weird has
1296 * changed inside libpng (probably).
1297 */
1298 if (st > 0x7fffffffU)
1299 png_error(pp, "unexpected write size");
1300
1301 /* Now process the bytes to be written. Do this in units of the space in the
1302 * output (write) buffer or, at the start 4 bytes for the chunk type and
1303 * length limited in any case by the amount of data.
1304 */
1305 while (st > 0)
1306 {
1307 if (writepos >= STORE_BUFFER_SIZE)
1308 store_storenew(ps), writepos = 0;
1309
1310 if (chunkpos < 4)
1311 {
1312 png_byte b = *pb++;
1313 --st;
1314 chunklen = (chunklen << 8) + b;
1315 ps->new.buffer[writepos++] = b;
1316 ++chunkpos;
1317 }
1318
1319 else if (chunkpos < 8)
1320 {
1321 png_byte b = *pb++;
1322 --st;
1323 chunktype = (chunktype << 8) + b;
1324 ps->new.buffer[writepos++] = b;
1325
1326 if (++chunkpos == 8)
1327 {
1328 chunklen &= 0xffffffffU;
1329 if (chunklen > 0x7fffffffU)
1330 png_error(pp, "chunk length too great");
1331
1332 chunktype &= 0xffffffffU;
1333 if (chunktype == CHUNK_IDAT)
1334 {
1335 if (chunklen > ~ps->IDAT_size)
1336 png_error(pp, "pngvalid internal image too large");
1337
1338 ps->IDAT_size += chunklen;
1339 }
1340
1341 else if (!valid_chunktype(chunktype))
1342 png_error(pp, "invalid chunk type");
1343
1344 chunklen += 12; /* for header and CRC */
1345 }
1346 }
1347
1348 else /* chunkpos >= 8 */
1349 {
1350 png_size_t cb = st;
1351
1352 if (cb > STORE_BUFFER_SIZE - writepos)
1353 cb = STORE_BUFFER_SIZE - writepos;
1354
1355 if (cb > chunklen - chunkpos/* bytes left in chunk*/)
1356 cb = (png_size_t)/*SAFE*/(chunklen - chunkpos);
1357
1358 memcpy(ps->new.buffer + writepos, pb, cb);
1359 chunkpos += (png_uint_32)/*SAFE*/cb;
1360 pb += cb;
1361 writepos += cb;
1362 st -= cb;
1363
1364 if (chunkpos >= chunklen) /* must be equal */
1365 chunkpos = chunktype = chunklen = 0;
1366 }
1367 } /* while (st > 0) */
1368
1369 ps->writepos = writepos;
1370 ps->chunkpos = chunkpos;
1371 ps->chunktype = chunktype;
1372 ps->chunklen = chunklen;
1373 }
1374
1375 static void PNGCBAPI
store_flush(png_structp ppIn)1376 store_flush(png_structp ppIn)
1377 {
1378 UNUSED(ppIn) /*DOES NOTHING*/
1379 }
1380
1381 #ifdef PNG_READ_SUPPORTED
1382 static size_t
store_read_buffer_size(png_store * ps)1383 store_read_buffer_size(png_store *ps)
1384 {
1385 /* Return the bytes available for read in the current buffer. */
1386 if (ps->next != &ps->current->data)
1387 return STORE_BUFFER_SIZE;
1388
1389 return ps->current->datacount;
1390 }
1391
1392 /* Return total bytes available for read. */
1393 static size_t
store_read_buffer_avail(png_store * ps)1394 store_read_buffer_avail(png_store *ps)
1395 {
1396 if (ps->current != NULL && ps->next != NULL)
1397 {
1398 png_store_buffer *next = &ps->current->data;
1399 size_t cbAvail = ps->current->datacount;
1400
1401 while (next != ps->next && next != NULL)
1402 {
1403 next = next->prev;
1404 cbAvail += STORE_BUFFER_SIZE;
1405 }
1406
1407 if (next != ps->next)
1408 png_error(ps->pread, "buffer read error");
1409
1410 if (cbAvail > ps->readpos)
1411 return cbAvail - ps->readpos;
1412 }
1413
1414 return 0;
1415 }
1416
1417 static int
store_read_buffer_next(png_store * ps)1418 store_read_buffer_next(png_store *ps)
1419 {
1420 png_store_buffer *pbOld = ps->next;
1421 png_store_buffer *pbNew = &ps->current->data;
1422 if (pbOld != pbNew)
1423 {
1424 while (pbNew != NULL && pbNew->prev != pbOld)
1425 pbNew = pbNew->prev;
1426
1427 if (pbNew != NULL)
1428 {
1429 ps->next = pbNew;
1430 ps->readpos = 0;
1431 return 1;
1432 }
1433
1434 png_error(ps->pread, "buffer lost");
1435 }
1436
1437 return 0; /* EOF or error */
1438 }
1439
1440 /* Need separate implementation and callback to allow use of the same code
1441 * during progressive read, where the io_ptr is set internally by libpng.
1442 */
1443 static void
store_read_imp(png_store * ps,png_bytep pb,png_size_t st)1444 store_read_imp(png_store *ps, png_bytep pb, png_size_t st)
1445 {
1446 if (ps->current == NULL || ps->next == NULL)
1447 png_error(ps->pread, "store state damaged");
1448
1449 while (st > 0)
1450 {
1451 size_t cbAvail = store_read_buffer_size(ps) - ps->readpos;
1452
1453 if (cbAvail > 0)
1454 {
1455 if (cbAvail > st) cbAvail = st;
1456 memcpy(pb, ps->next->buffer + ps->readpos, cbAvail);
1457 st -= cbAvail;
1458 pb += cbAvail;
1459 ps->readpos += cbAvail;
1460 }
1461
1462 else if (!store_read_buffer_next(ps))
1463 png_error(ps->pread, "read beyond end of file");
1464 }
1465 }
1466
1467 static png_size_t
store_read_chunk(png_store * ps,png_bytep pb,const png_size_t max,const png_size_t min)1468 store_read_chunk(png_store *ps, png_bytep pb, const png_size_t max,
1469 const png_size_t min)
1470 {
1471 png_uint_32 chunklen = ps->chunklen;
1472 png_uint_32 chunktype = ps->chunktype;
1473 png_uint_32 chunkpos = ps->chunkpos;
1474 png_size_t st = max;
1475
1476 if (st > 0) do
1477 {
1478 if (chunkpos >= chunklen) /* end of last chunk */
1479 {
1480 png_byte buffer[8];
1481
1482 /* Read the header of the next chunk: */
1483 store_read_imp(ps, buffer, 8U);
1484 chunklen = png_get_uint_32(buffer) + 12U;
1485 chunktype = png_get_uint_32(buffer+4U);
1486 chunkpos = 0U; /* Position read so far */
1487 }
1488
1489 if (chunktype == CHUNK_IDAT)
1490 {
1491 png_uint_32 IDAT_pos = ps->IDAT_pos;
1492 png_uint_32 IDAT_len = ps->IDAT_len;
1493 png_uint_32 IDAT_size = ps->IDAT_size;
1494
1495 /* The IDAT headers are constructed here; skip the input header. */
1496 if (chunkpos < 8U)
1497 chunkpos = 8U;
1498
1499 if (IDAT_pos == IDAT_len)
1500 {
1501 png_byte random = random_byte();
1502
1503 /* Make a new IDAT chunk, if IDAT_len is 0 this is the first IDAT,
1504 * if IDAT_size is 0 this is the end. At present this is set up
1505 * using a random number so that there is a 25% chance before
1506 * the start of the first IDAT chunk being 0 length.
1507 */
1508 if (IDAT_len == 0U) /* First IDAT */
1509 {
1510 switch (random & 3U)
1511 {
1512 case 0U: IDAT_len = 12U; break; /* 0 bytes */
1513 case 1U: IDAT_len = 13U; break; /* 1 byte */
1514 default: IDAT_len = random_u32();
1515 IDAT_len %= IDAT_size;
1516 IDAT_len += 13U; /* 1..IDAT_size bytes */
1517 break;
1518 }
1519 }
1520
1521 else if (IDAT_size == 0U) /* all IDAT data read */
1522 {
1523 /* The last (IDAT) chunk should be positioned at the CRC now: */
1524 if (chunkpos != chunklen-4U)
1525 png_error(ps->pread, "internal: IDAT size mismatch");
1526
1527 /* The only option here is to add a zero length IDAT, this
1528 * happens 25% of the time. Because of the check above
1529 * chunklen-4U-chunkpos must be zero, we just need to skip the
1530 * CRC now.
1531 */
1532 if ((random & 3U) == 0U)
1533 IDAT_len = 12U; /* Output another 0 length IDAT */
1534
1535 else
1536 {
1537 /* End of IDATs, skip the CRC to make the code above load the
1538 * next chunk header next time round.
1539 */
1540 png_byte buffer[4];
1541
1542 store_read_imp(ps, buffer, 4U);
1543 chunkpos += 4U;
1544 ps->IDAT_pos = IDAT_pos;
1545 ps->IDAT_len = IDAT_len;
1546 ps->IDAT_size = 0U;
1547 continue; /* Read the next chunk */
1548 }
1549 }
1550
1551 else
1552 {
1553 /* Middle of IDATs, use 'random' to determine the number of bits
1554 * to use in the IDAT length.
1555 */
1556 IDAT_len = random_u32();
1557 IDAT_len &= (1U << (1U + random % ps->IDAT_bits)) - 1U;
1558 if (IDAT_len > IDAT_size)
1559 IDAT_len = IDAT_size;
1560 IDAT_len += 12U; /* zero bytes may occur */
1561 }
1562
1563 IDAT_pos = 0U;
1564 ps->IDAT_crc = 0x35af061e; /* Ie: crc32(0UL, "IDAT", 4) */
1565 } /* IDAT_pos == IDAT_len */
1566
1567 if (IDAT_pos < 8U) /* Return the header */ do
1568 {
1569 png_uint_32 b;
1570 unsigned int shift;
1571
1572 if (IDAT_pos < 4U)
1573 b = IDAT_len - 12U;
1574
1575 else
1576 b = CHUNK_IDAT;
1577
1578 shift = 3U & IDAT_pos;
1579 ++IDAT_pos;
1580
1581 if (shift < 3U)
1582 b >>= 8U*(3U-shift);
1583
1584 *pb++ = 0xffU & b;
1585 }
1586 while (--st > 0 && IDAT_pos < 8);
1587
1588 else if (IDAT_pos < IDAT_len - 4U) /* I.e not the CRC */
1589 {
1590 if (chunkpos < chunklen-4U)
1591 {
1592 uInt avail = (uInt)-1;
1593
1594 if (avail > (IDAT_len-4U) - IDAT_pos)
1595 avail = (uInt)/*SAFE*/((IDAT_len-4U) - IDAT_pos);
1596
1597 if (avail > st)
1598 avail = (uInt)/*SAFE*/st;
1599
1600 if (avail > (chunklen-4U) - chunkpos)
1601 avail = (uInt)/*SAFE*/((chunklen-4U) - chunkpos);
1602
1603 store_read_imp(ps, pb, avail);
1604 ps->IDAT_crc = crc32(ps->IDAT_crc, pb, avail);
1605 pb += (png_size_t)/*SAFE*/avail;
1606 st -= (png_size_t)/*SAFE*/avail;
1607 chunkpos += (png_uint_32)/*SAFE*/avail;
1608 IDAT_size -= (png_uint_32)/*SAFE*/avail;
1609 IDAT_pos += (png_uint_32)/*SAFE*/avail;
1610 }
1611
1612 else /* skip the input CRC */
1613 {
1614 png_byte buffer[4];
1615
1616 store_read_imp(ps, buffer, 4U);
1617 chunkpos += 4U;
1618 }
1619 }
1620
1621 else /* IDAT crc */ do
1622 {
1623 uLong b = ps->IDAT_crc;
1624 unsigned int shift = (IDAT_len - IDAT_pos); /* 4..1 */
1625 ++IDAT_pos;
1626
1627 if (shift > 1U)
1628 b >>= 8U*(shift-1U);
1629
1630 *pb++ = 0xffU & b;
1631 }
1632 while (--st > 0 && IDAT_pos < IDAT_len);
1633
1634 ps->IDAT_pos = IDAT_pos;
1635 ps->IDAT_len = IDAT_len;
1636 ps->IDAT_size = IDAT_size;
1637 }
1638
1639 else /* !IDAT */
1640 {
1641 /* If there is still some pending IDAT data after the IDAT chunks have
1642 * been processed there is a problem:
1643 */
1644 if (ps->IDAT_len > 0 && ps->IDAT_size > 0)
1645 png_error(ps->pread, "internal: missing IDAT data");
1646
1647 if (chunktype == CHUNK_IEND && ps->IDAT_len == 0U)
1648 png_error(ps->pread, "internal: missing IDAT");
1649
1650 if (chunkpos < 8U) /* Return the header */ do
1651 {
1652 png_uint_32 b;
1653 unsigned int shift;
1654
1655 if (chunkpos < 4U)
1656 b = chunklen - 12U;
1657
1658 else
1659 b = chunktype;
1660
1661 shift = 3U & chunkpos;
1662 ++chunkpos;
1663
1664 if (shift < 3U)
1665 b >>= 8U*(3U-shift);
1666
1667 *pb++ = 0xffU & b;
1668 }
1669 while (--st > 0 && chunkpos < 8);
1670
1671 else /* Return chunk bytes, including the CRC */
1672 {
1673 png_size_t avail = st;
1674
1675 if (avail > chunklen - chunkpos)
1676 avail = (png_size_t)/*SAFE*/(chunklen - chunkpos);
1677
1678 store_read_imp(ps, pb, avail);
1679 pb += avail;
1680 st -= avail;
1681 chunkpos += (png_uint_32)/*SAFE*/avail;
1682
1683 /* Check for end of chunk and end-of-file; don't try to read a new
1684 * chunk header at this point unless instructed to do so by 'min'.
1685 */
1686 if (chunkpos >= chunklen && max-st >= min &&
1687 store_read_buffer_avail(ps) == 0)
1688 break;
1689 }
1690 } /* !IDAT */
1691 }
1692 while (st > 0);
1693
1694 ps->chunklen = chunklen;
1695 ps->chunktype = chunktype;
1696 ps->chunkpos = chunkpos;
1697
1698 return st; /* space left */
1699 }
1700
1701 static void PNGCBAPI
store_read(png_structp ppIn,png_bytep pb,png_size_t st)1702 store_read(png_structp ppIn, png_bytep pb, png_size_t st)
1703 {
1704 png_const_structp pp = ppIn;
1705 png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
1706
1707 if (ps == NULL || ps->pread != pp)
1708 png_error(pp, "bad store read call");
1709
1710 store_read_chunk(ps, pb, st, st);
1711 }
1712
1713 static void
store_progressive_read(png_store * ps,png_structp pp,png_infop pi)1714 store_progressive_read(png_store *ps, png_structp pp, png_infop pi)
1715 {
1716 if (ps->pread != pp || ps->current == NULL || ps->next == NULL)
1717 png_error(pp, "store state damaged (progressive)");
1718
1719 /* This is another Horowitz and Hill random noise generator. In this case
1720 * the aim is to stress the progressive reader with truly horrible variable
1721 * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
1722 * is generated. We could probably just count from 1 to 32767 and get as
1723 * good a result.
1724 */
1725 while (store_read_buffer_avail(ps) > 0)
1726 {
1727 static png_uint_32 noise = 2;
1728 png_size_t cb;
1729 png_byte buffer[512];
1730
1731 /* Generate 15 more bits of stuff: */
1732 noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
1733 cb = noise & 0x1ff;
1734 cb -= store_read_chunk(ps, buffer, cb, 1);
1735 png_process_data(pp, pi, buffer, cb);
1736 }
1737 }
1738 #endif /* PNG_READ_SUPPORTED */
1739
1740 /* The caller must fill this in: */
1741 static store_palette_entry *
store_write_palette(png_store * ps,int npalette)1742 store_write_palette(png_store *ps, int npalette)
1743 {
1744 if (ps->pwrite == NULL)
1745 store_log(ps, NULL, "attempt to write palette without write stream", 1);
1746
1747 if (ps->palette != NULL)
1748 png_error(ps->pwrite, "multiple store_write_palette calls");
1749
1750 /* This function can only return NULL if called with '0'! */
1751 if (npalette > 0)
1752 {
1753 ps->palette = voidcast(store_palette_entry*, malloc(npalette *
1754 sizeof *ps->palette));
1755
1756 if (ps->palette == NULL)
1757 png_error(ps->pwrite, "store new palette: OOM");
1758
1759 ps->npalette = npalette;
1760 }
1761
1762 return ps->palette;
1763 }
1764
1765 #ifdef PNG_READ_SUPPORTED
1766 static store_palette_entry *
store_current_palette(png_store * ps,int * npalette)1767 store_current_palette(png_store *ps, int *npalette)
1768 {
1769 /* This is an internal error (the call has been made outside a read
1770 * operation.)
1771 */
1772 if (ps->current == NULL)
1773 {
1774 store_log(ps, ps->pread, "no current stream for palette", 1);
1775 return NULL;
1776 }
1777
1778 /* The result may be null if there is no palette. */
1779 *npalette = ps->current->npalette;
1780 return ps->current->palette;
1781 }
1782 #endif /* PNG_READ_SUPPORTED */
1783
1784 /***************************** MEMORY MANAGEMENT*** ***************************/
1785 #ifdef PNG_USER_MEM_SUPPORTED
1786 /* A store_memory is simply the header for an allocated block of memory. The
1787 * pointer returned to libpng is just after the end of the header block, the
1788 * allocated memory is followed by a second copy of the 'mark'.
1789 */
1790 typedef struct store_memory
1791 {
1792 store_pool *pool; /* Originating pool */
1793 struct store_memory *next; /* Singly linked list */
1794 png_alloc_size_t size; /* Size of memory allocated */
1795 png_byte mark[4]; /* ID marker */
1796 } store_memory;
1797
1798 /* Handle a fatal error in memory allocation. This calls png_error if the
1799 * libpng struct is non-NULL, else it outputs a message and returns. This means
1800 * that a memory problem while libpng is running will abort (png_error) the
1801 * handling of particular file while one in cleanup (after the destroy of the
1802 * struct has returned) will simply keep going and free (or attempt to free)
1803 * all the memory.
1804 */
1805 static void
store_pool_error(png_store * ps,png_const_structp pp,const char * msg)1806 store_pool_error(png_store *ps, png_const_structp pp, const char *msg)
1807 {
1808 if (pp != NULL)
1809 png_error(pp, msg);
1810
1811 /* Else we have to do it ourselves. png_error eventually calls store_log,
1812 * above. store_log accepts a NULL png_structp - it just changes what gets
1813 * output by store_message.
1814 */
1815 store_log(ps, pp, msg, 1 /* error */);
1816 }
1817
1818 static void
store_memory_free(png_const_structp pp,store_pool * pool,store_memory * memory)1819 store_memory_free(png_const_structp pp, store_pool *pool, store_memory *memory)
1820 {
1821 /* Note that pp may be NULL (see store_pool_delete below), the caller has
1822 * found 'memory' in pool->list *and* unlinked this entry, so this is a valid
1823 * pointer (for sure), but the contents may have been trashed.
1824 */
1825 if (memory->pool != pool)
1826 store_pool_error(pool->store, pp, "memory corrupted (pool)");
1827
1828 else if (memcmp(memory->mark, pool->mark, sizeof memory->mark) != 0)
1829 store_pool_error(pool->store, pp, "memory corrupted (start)");
1830
1831 /* It should be safe to read the size field now. */
1832 else
1833 {
1834 png_alloc_size_t cb = memory->size;
1835
1836 if (cb > pool->max)
1837 store_pool_error(pool->store, pp, "memory corrupted (size)");
1838
1839 else if (memcmp((png_bytep)(memory+1)+cb, pool->mark, sizeof pool->mark)
1840 != 0)
1841 store_pool_error(pool->store, pp, "memory corrupted (end)");
1842
1843 /* Finally give the library a chance to find problems too: */
1844 else
1845 {
1846 pool->current -= cb;
1847 free(memory);
1848 }
1849 }
1850 }
1851
1852 static void
store_pool_delete(png_store * ps,store_pool * pool)1853 store_pool_delete(png_store *ps, store_pool *pool)
1854 {
1855 if (pool->list != NULL)
1856 {
1857 fprintf(stderr, "%s: %s %s: memory lost (list follows):\n", ps->test,
1858 pool == &ps->read_memory_pool ? "read" : "write",
1859 pool == &ps->read_memory_pool ? (ps->current != NULL ?
1860 ps->current->name : "unknown file") : ps->wname);
1861 ++ps->nerrors;
1862
1863 do
1864 {
1865 store_memory *next = pool->list;
1866 pool->list = next->next;
1867 next->next = NULL;
1868
1869 fprintf(stderr, "\t%lu bytes @ %p\n",
1870 (unsigned long)next->size, (const void*)(next+1));
1871 /* The NULL means this will always return, even if the memory is
1872 * corrupted.
1873 */
1874 store_memory_free(NULL, pool, next);
1875 }
1876 while (pool->list != NULL);
1877 }
1878
1879 /* And reset the other fields too for the next time. */
1880 if (pool->max > pool->max_max) pool->max_max = pool->max;
1881 pool->max = 0;
1882 if (pool->current != 0) /* unexpected internal error */
1883 fprintf(stderr, "%s: %s %s: memory counter mismatch (internal error)\n",
1884 ps->test, pool == &ps->read_memory_pool ? "read" : "write",
1885 pool == &ps->read_memory_pool ? (ps->current != NULL ?
1886 ps->current->name : "unknown file") : ps->wname);
1887 pool->current = 0;
1888
1889 if (pool->limit > pool->max_limit)
1890 pool->max_limit = pool->limit;
1891
1892 pool->limit = 0;
1893
1894 if (pool->total > pool->max_total)
1895 pool->max_total = pool->total;
1896
1897 pool->total = 0;
1898
1899 /* Get a new mark too. */
1900 store_pool_mark(pool->mark);
1901 }
1902
1903 /* The memory callbacks: */
1904 static png_voidp PNGCBAPI
store_malloc(png_structp ppIn,png_alloc_size_t cb)1905 store_malloc(png_structp ppIn, png_alloc_size_t cb)
1906 {
1907 png_const_structp pp = ppIn;
1908 store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
1909 store_memory *new = voidcast(store_memory*, malloc(cb + (sizeof *new) +
1910 (sizeof pool->mark)));
1911
1912 if (new != NULL)
1913 {
1914 if (cb > pool->max)
1915 pool->max = cb;
1916
1917 pool->current += cb;
1918
1919 if (pool->current > pool->limit)
1920 pool->limit = pool->current;
1921
1922 pool->total += cb;
1923
1924 new->size = cb;
1925 memcpy(new->mark, pool->mark, sizeof new->mark);
1926 memcpy((png_byte*)(new+1) + cb, pool->mark, sizeof pool->mark);
1927 new->pool = pool;
1928 new->next = pool->list;
1929 pool->list = new;
1930 ++new;
1931 }
1932
1933 else
1934 {
1935 /* NOTE: the PNG user malloc function cannot use the png_ptr it is passed
1936 * other than to retrieve the allocation pointer! libpng calls the
1937 * store_malloc callback in two basic cases:
1938 *
1939 * 1) From png_malloc; png_malloc will do a png_error itself if NULL is
1940 * returned.
1941 * 2) From png_struct or png_info structure creation; png_malloc is
1942 * to return so cleanup can be performed.
1943 *
1944 * To handle this store_malloc can log a message, but can't do anything
1945 * else.
1946 */
1947 store_log(pool->store, pp, "out of memory", 1 /* is_error */);
1948 }
1949
1950 return new;
1951 }
1952
1953 static void PNGCBAPI
store_free(png_structp ppIn,png_voidp memory)1954 store_free(png_structp ppIn, png_voidp memory)
1955 {
1956 png_const_structp pp = ppIn;
1957 store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
1958 store_memory *this = voidcast(store_memory*, memory), **test;
1959
1960 /* Because libpng calls store_free with a dummy png_struct when deleting
1961 * png_struct or png_info via png_destroy_struct_2 it is necessary to check
1962 * the passed in png_structp to ensure it is valid, and not pass it to
1963 * png_error if it is not.
1964 */
1965 if (pp != pool->store->pread && pp != pool->store->pwrite)
1966 pp = NULL;
1967
1968 /* First check that this 'memory' really is valid memory - it must be in the
1969 * pool list. If it is, use the shared memory_free function to free it.
1970 */
1971 --this;
1972 for (test = &pool->list; *test != this; test = &(*test)->next)
1973 {
1974 if (*test == NULL)
1975 {
1976 store_pool_error(pool->store, pp, "bad pointer to free");
1977 return;
1978 }
1979 }
1980
1981 /* Unlink this entry, *test == this. */
1982 *test = this->next;
1983 this->next = NULL;
1984 store_memory_free(pp, pool, this);
1985 }
1986 #endif /* PNG_USER_MEM_SUPPORTED */
1987
1988 /* Setup functions. */
1989 /* Cleanup when aborting a write or after storing the new file. */
1990 static void
store_write_reset(png_store * ps)1991 store_write_reset(png_store *ps)
1992 {
1993 if (ps->pwrite != NULL)
1994 {
1995 anon_context(ps);
1996
1997 Try
1998 png_destroy_write_struct(&ps->pwrite, &ps->piwrite);
1999
2000 Catch_anonymous
2001 {
2002 /* memory corruption: continue. */
2003 }
2004
2005 ps->pwrite = NULL;
2006 ps->piwrite = NULL;
2007 }
2008
2009 /* And make sure that all the memory has been freed - this will output
2010 * spurious errors in the case of memory corruption above, but this is safe.
2011 */
2012 # ifdef PNG_USER_MEM_SUPPORTED
2013 store_pool_delete(ps, &ps->write_memory_pool);
2014 # endif
2015
2016 store_freenew(ps);
2017 }
2018
2019 /* The following is the main write function, it returns a png_struct and,
2020 * optionally, a png_info suitable for writiing a new PNG file. Use
2021 * store_storefile above to record this file after it has been written. The
2022 * returned libpng structures as destroyed by store_write_reset above.
2023 */
2024 static png_structp
set_store_for_write(png_store * ps,png_infopp ppi,const char * name)2025 set_store_for_write(png_store *ps, png_infopp ppi, const char *name)
2026 {
2027 anon_context(ps);
2028
2029 Try
2030 {
2031 if (ps->pwrite != NULL)
2032 png_error(ps->pwrite, "write store already in use");
2033
2034 store_write_reset(ps);
2035 safecat(ps->wname, sizeof ps->wname, 0, name);
2036
2037 /* Don't do the slow memory checks if doing a speed test, also if user
2038 * memory is not supported we can't do it anyway.
2039 */
2040 # ifdef PNG_USER_MEM_SUPPORTED
2041 if (!ps->speed)
2042 ps->pwrite = png_create_write_struct_2(PNG_LIBPNG_VER_STRING,
2043 ps, store_error, store_warning, &ps->write_memory_pool,
2044 store_malloc, store_free);
2045
2046 else
2047 # endif
2048 ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING,
2049 ps, store_error, store_warning);
2050
2051 png_set_write_fn(ps->pwrite, ps, store_write, store_flush);
2052
2053 # ifdef PNG_SET_OPTION_SUPPORTED
2054 {
2055 int opt;
2056 for (opt=0; opt<ps->noptions; ++opt)
2057 if (png_set_option(ps->pwrite, ps->options[opt].option,
2058 ps->options[opt].setting) == PNG_OPTION_INVALID)
2059 png_error(ps->pwrite, "png option invalid");
2060 }
2061 # endif
2062
2063 if (ppi != NULL)
2064 *ppi = ps->piwrite = png_create_info_struct(ps->pwrite);
2065 }
2066
2067 Catch_anonymous
2068 return NULL;
2069
2070 return ps->pwrite;
2071 }
2072
2073 /* Cleanup when finished reading (either due to error or in the success case).
2074 * This routine exists even when there is no read support to make the code
2075 * tidier (avoid a mass of ifdefs) and so easier to maintain.
2076 */
2077 static void
store_read_reset(png_store * ps)2078 store_read_reset(png_store *ps)
2079 {
2080 # ifdef PNG_READ_SUPPORTED
2081 if (ps->pread != NULL)
2082 {
2083 anon_context(ps);
2084
2085 Try
2086 png_destroy_read_struct(&ps->pread, &ps->piread, NULL);
2087
2088 Catch_anonymous
2089 {
2090 /* error already output: continue */
2091 }
2092
2093 ps->pread = NULL;
2094 ps->piread = NULL;
2095 }
2096 # endif
2097
2098 # ifdef PNG_USER_MEM_SUPPORTED
2099 /* Always do this to be safe. */
2100 store_pool_delete(ps, &ps->read_memory_pool);
2101 # endif
2102
2103 ps->current = NULL;
2104 ps->next = NULL;
2105 ps->readpos = 0;
2106 ps->validated = 0;
2107
2108 ps->chunkpos = 8;
2109 ps->chunktype = 0;
2110 ps->chunklen = 16;
2111 ps->IDAT_size = 0;
2112 }
2113
2114 #ifdef PNG_READ_SUPPORTED
2115 static void
store_read_set(png_store * ps,png_uint_32 id)2116 store_read_set(png_store *ps, png_uint_32 id)
2117 {
2118 png_store_file *pf = ps->saved;
2119
2120 while (pf != NULL)
2121 {
2122 if (pf->id == id)
2123 {
2124 ps->current = pf;
2125 ps->next = NULL;
2126 ps->IDAT_size = pf->IDAT_size;
2127 ps->IDAT_bits = pf->IDAT_bits; /* just a cache */
2128 ps->IDAT_len = 0;
2129 ps->IDAT_pos = 0;
2130 ps->IDAT_crc = 0UL;
2131 store_read_buffer_next(ps);
2132 return;
2133 }
2134
2135 pf = pf->next;
2136 }
2137
2138 {
2139 size_t pos;
2140 char msg[FILE_NAME_SIZE+64];
2141
2142 pos = standard_name_from_id(msg, sizeof msg, 0, id);
2143 pos = safecat(msg, sizeof msg, pos, ": file not found");
2144 png_error(ps->pread, msg);
2145 }
2146 }
2147
2148 /* The main interface for reading a saved file - pass the id number of the file
2149 * to retrieve. Ids must be unique or the earlier file will be hidden. The API
2150 * returns a png_struct and, optionally, a png_info. Both of these will be
2151 * destroyed by store_read_reset above.
2152 */
2153 static png_structp
set_store_for_read(png_store * ps,png_infopp ppi,png_uint_32 id,const char * name)2154 set_store_for_read(png_store *ps, png_infopp ppi, png_uint_32 id,
2155 const char *name)
2156 {
2157 /* Set the name for png_error */
2158 safecat(ps->test, sizeof ps->test, 0, name);
2159
2160 if (ps->pread != NULL)
2161 png_error(ps->pread, "read store already in use");
2162
2163 store_read_reset(ps);
2164
2165 /* Both the create APIs can return NULL if used in their default mode
2166 * (because there is no other way of handling an error because the jmp_buf
2167 * by default is stored in png_struct and that has not been allocated!)
2168 * However, given that store_error works correctly in these circumstances
2169 * we don't ever expect NULL in this program.
2170 */
2171 # ifdef PNG_USER_MEM_SUPPORTED
2172 if (!ps->speed)
2173 ps->pread = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, ps,
2174 store_error, store_warning, &ps->read_memory_pool, store_malloc,
2175 store_free);
2176
2177 else
2178 # endif
2179 ps->pread = png_create_read_struct(PNG_LIBPNG_VER_STRING, ps, store_error,
2180 store_warning);
2181
2182 if (ps->pread == NULL)
2183 {
2184 struct exception_context *the_exception_context = &ps->exception_context;
2185
2186 store_log(ps, NULL, "png_create_read_struct returned NULL (unexpected)",
2187 1 /*error*/);
2188
2189 Throw ps;
2190 }
2191
2192 # ifdef PNG_SET_OPTION_SUPPORTED
2193 {
2194 int opt;
2195 for (opt=0; opt<ps->noptions; ++opt)
2196 if (png_set_option(ps->pread, ps->options[opt].option,
2197 ps->options[opt].setting) == PNG_OPTION_INVALID)
2198 png_error(ps->pread, "png option invalid");
2199 }
2200 # endif
2201
2202 store_read_set(ps, id);
2203
2204 if (ppi != NULL)
2205 *ppi = ps->piread = png_create_info_struct(ps->pread);
2206
2207 return ps->pread;
2208 }
2209 #endif /* PNG_READ_SUPPORTED */
2210
2211 /* The overall cleanup of a store simply calls the above then removes all the
2212 * saved files. This does not delete the store itself.
2213 */
2214 static void
store_delete(png_store * ps)2215 store_delete(png_store *ps)
2216 {
2217 store_write_reset(ps);
2218 store_read_reset(ps);
2219 store_freefile(&ps->saved);
2220 store_image_free(ps, NULL);
2221 }
2222
2223 /*********************** PNG FILE MODIFICATION ON READ ************************/
2224 /* Files may be modified on read. The following structure contains a complete
2225 * png_store together with extra members to handle modification and a special
2226 * read callback for libpng. To use this the 'modifications' field must be set
2227 * to a list of png_modification structures that actually perform the
2228 * modification, otherwise a png_modifier is functionally equivalent to a
2229 * png_store. There is a special read function, set_modifier_for_read, which
2230 * replaces set_store_for_read.
2231 */
2232 typedef enum modifier_state
2233 {
2234 modifier_start, /* Initial value */
2235 modifier_signature, /* Have a signature */
2236 modifier_IHDR /* Have an IHDR */
2237 } modifier_state;
2238
2239 typedef struct CIE_color
2240 {
2241 /* A single CIE tristimulus value, representing the unique response of a
2242 * standard observer to a variety of light spectra. The observer recognizes
2243 * all spectra that produce this response as the same color, therefore this
2244 * is effectively a description of a color.
2245 */
2246 double X, Y, Z;
2247 } CIE_color;
2248
2249 typedef struct color_encoding
2250 {
2251 /* A description of an (R,G,B) encoding of color (as defined above); this
2252 * includes the actual colors of the (R,G,B) triples (1,0,0), (0,1,0) and
2253 * (0,0,1) plus an encoding value that is used to encode the linear
2254 * components R, G and B to give the actual values R^gamma, G^gamma and
2255 * B^gamma that are stored.
2256 */
2257 double gamma; /* Encoding (file) gamma of space */
2258 CIE_color red, green, blue; /* End points */
2259 } color_encoding;
2260
2261 #ifdef PNG_READ_SUPPORTED
2262 #if defined PNG_READ_TRANSFORMS_SUPPORTED && defined PNG_READ_cHRM_SUPPORTED
2263 static double
chromaticity_x(CIE_color c)2264 chromaticity_x(CIE_color c)
2265 {
2266 return c.X / (c.X + c.Y + c.Z);
2267 }
2268
2269 static double
chromaticity_y(CIE_color c)2270 chromaticity_y(CIE_color c)
2271 {
2272 return c.Y / (c.X + c.Y + c.Z);
2273 }
2274
2275 static CIE_color
white_point(const color_encoding * encoding)2276 white_point(const color_encoding *encoding)
2277 {
2278 CIE_color white;
2279
2280 white.X = encoding->red.X + encoding->green.X + encoding->blue.X;
2281 white.Y = encoding->red.Y + encoding->green.Y + encoding->blue.Y;
2282 white.Z = encoding->red.Z + encoding->green.Z + encoding->blue.Z;
2283
2284 return white;
2285 }
2286 #endif /* READ_TRANSFORMS && READ_cHRM */
2287
2288 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2289 static void
normalize_color_encoding(color_encoding * encoding)2290 normalize_color_encoding(color_encoding *encoding)
2291 {
2292 const double whiteY = encoding->red.Y + encoding->green.Y +
2293 encoding->blue.Y;
2294
2295 if (whiteY != 1)
2296 {
2297 encoding->red.X /= whiteY;
2298 encoding->red.Y /= whiteY;
2299 encoding->red.Z /= whiteY;
2300 encoding->green.X /= whiteY;
2301 encoding->green.Y /= whiteY;
2302 encoding->green.Z /= whiteY;
2303 encoding->blue.X /= whiteY;
2304 encoding->blue.Y /= whiteY;
2305 encoding->blue.Z /= whiteY;
2306 }
2307 }
2308 #endif
2309
2310 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
2311 static size_t
safecat_color_encoding(char * buffer,size_t bufsize,size_t pos,const color_encoding * e,double encoding_gamma)2312 safecat_color_encoding(char *buffer, size_t bufsize, size_t pos,
2313 const color_encoding *e, double encoding_gamma)
2314 {
2315 if (e != 0)
2316 {
2317 if (encoding_gamma != 0)
2318 pos = safecat(buffer, bufsize, pos, "(");
2319 pos = safecat(buffer, bufsize, pos, "R(");
2320 pos = safecatd(buffer, bufsize, pos, e->red.X, 4);
2321 pos = safecat(buffer, bufsize, pos, ",");
2322 pos = safecatd(buffer, bufsize, pos, e->red.Y, 4);
2323 pos = safecat(buffer, bufsize, pos, ",");
2324 pos = safecatd(buffer, bufsize, pos, e->red.Z, 4);
2325 pos = safecat(buffer, bufsize, pos, "),G(");
2326 pos = safecatd(buffer, bufsize, pos, e->green.X, 4);
2327 pos = safecat(buffer, bufsize, pos, ",");
2328 pos = safecatd(buffer, bufsize, pos, e->green.Y, 4);
2329 pos = safecat(buffer, bufsize, pos, ",");
2330 pos = safecatd(buffer, bufsize, pos, e->green.Z, 4);
2331 pos = safecat(buffer, bufsize, pos, "),B(");
2332 pos = safecatd(buffer, bufsize, pos, e->blue.X, 4);
2333 pos = safecat(buffer, bufsize, pos, ",");
2334 pos = safecatd(buffer, bufsize, pos, e->blue.Y, 4);
2335 pos = safecat(buffer, bufsize, pos, ",");
2336 pos = safecatd(buffer, bufsize, pos, e->blue.Z, 4);
2337 pos = safecat(buffer, bufsize, pos, ")");
2338 if (encoding_gamma != 0)
2339 pos = safecat(buffer, bufsize, pos, ")");
2340 }
2341
2342 if (encoding_gamma != 0)
2343 {
2344 pos = safecat(buffer, bufsize, pos, "^");
2345 pos = safecatd(buffer, bufsize, pos, encoding_gamma, 5);
2346 }
2347
2348 return pos;
2349 }
2350 #endif /* READ_TRANSFORMS */
2351 #endif /* PNG_READ_SUPPORTED */
2352
2353 typedef struct png_modifier
2354 {
2355 png_store this; /* I am a png_store */
2356 struct png_modification *modifications; /* Changes to make */
2357
2358 modifier_state state; /* My state */
2359
2360 /* Information from IHDR: */
2361 png_byte bit_depth; /* From IHDR */
2362 png_byte colour_type; /* From IHDR */
2363
2364 /* While handling PLTE, IDAT and IEND these chunks may be pended to allow
2365 * other chunks to be inserted.
2366 */
2367 png_uint_32 pending_len;
2368 png_uint_32 pending_chunk;
2369
2370 /* Test values */
2371 double *gammas;
2372 unsigned int ngammas;
2373 unsigned int ngamma_tests; /* Number of gamma tests to run*/
2374 double current_gamma; /* 0 if not set */
2375 const color_encoding *encodings;
2376 unsigned int nencodings;
2377 const color_encoding *current_encoding; /* If an encoding has been set */
2378 unsigned int encoding_counter; /* For iteration */
2379 int encoding_ignored; /* Something overwrote it */
2380
2381 /* Control variables used to iterate through possible encodings, the
2382 * following must be set to 0 and tested by the function that uses the
2383 * png_modifier because the modifier only sets it to 1 (true.)
2384 */
2385 unsigned int repeat :1; /* Repeat this transform test. */
2386 unsigned int test_uses_encoding :1;
2387
2388 /* Lowest sbit to test (pre-1.7 libpng fails for sbit < 8) */
2389 png_byte sbitlow;
2390
2391 /* Error control - these are the limits on errors accepted by the gamma tests
2392 * below.
2393 */
2394 double maxout8; /* Maximum output value error */
2395 double maxabs8; /* Absolute sample error 0..1 */
2396 double maxcalc8; /* Absolute sample error 0..1 */
2397 double maxpc8; /* Percentage sample error 0..100% */
2398 double maxout16; /* Maximum output value error */
2399 double maxabs16; /* Absolute sample error 0..1 */
2400 double maxcalc16;/* Absolute sample error 0..1 */
2401 double maxcalcG; /* Absolute sample error 0..1 */
2402 double maxpc16; /* Percentage sample error 0..100% */
2403
2404 /* This is set by transforms that need to allow a higher limit, it is an
2405 * internal check on pngvalid to ensure that the calculated error limits are
2406 * not ridiculous; without this it is too easy to make a mistake in pngvalid
2407 * that allows any value through.
2408 *
2409 * NOTE: this is not checked in release builds.
2410 */
2411 double limit; /* limit on error values, normally 4E-3 */
2412
2413 /* Log limits - values above this are logged, but not necessarily
2414 * warned.
2415 */
2416 double log8; /* Absolute error in 8 bits to log */
2417 double log16; /* Absolute error in 16 bits to log */
2418
2419 /* Logged 8 and 16 bit errors ('output' values): */
2420 double error_gray_2;
2421 double error_gray_4;
2422 double error_gray_8;
2423 double error_gray_16;
2424 double error_color_8;
2425 double error_color_16;
2426 double error_indexed;
2427
2428 /* Flags: */
2429 /* Whether to call png_read_update_info, not png_read_start_image, and how
2430 * many times to call it.
2431 */
2432 int use_update_info;
2433
2434 /* Whether or not to interlace. */
2435 int interlace_type :9; /* int, but must store '1' */
2436
2437 /* Run the standard tests? */
2438 unsigned int test_standard :1;
2439
2440 /* Run the odd-sized image and interlace read/write tests? */
2441 unsigned int test_size :1;
2442
2443 /* Run tests on reading with a combination of transforms, */
2444 unsigned int test_transform :1;
2445 unsigned int test_tRNS :1; /* Includes tRNS images */
2446
2447 /* When to use the use_input_precision option, this controls the gamma
2448 * validation code checks. If set any value that is within the transformed
2449 * range input-.5 to input+.5 will be accepted, otherwise the value must be
2450 * within the normal limits. It should not be necessary to set this; the
2451 * result should always be exact within the permitted error limits.
2452 */
2453 unsigned int use_input_precision :1;
2454 unsigned int use_input_precision_sbit :1;
2455 unsigned int use_input_precision_16to8 :1;
2456
2457 /* If set assume that the calculation bit depth is set by the input
2458 * precision, not the output precision.
2459 */
2460 unsigned int calculations_use_input_precision :1;
2461
2462 /* If set assume that the calculations are done in 16 bits even if the sample
2463 * depth is 8 bits.
2464 */
2465 unsigned int assume_16_bit_calculations :1;
2466
2467 /* Which gamma tests to run: */
2468 unsigned int test_gamma_threshold :1;
2469 unsigned int test_gamma_transform :1; /* main tests */
2470 unsigned int test_gamma_sbit :1;
2471 unsigned int test_gamma_scale16 :1;
2472 unsigned int test_gamma_background :1;
2473 unsigned int test_gamma_alpha_mode :1;
2474 unsigned int test_gamma_expand16 :1;
2475 unsigned int test_exhaustive :1;
2476
2477 /* Whether or not to run the low-bit-depth grayscale tests. This fails on
2478 * gamma images in some cases because of gross inaccuracies in the grayscale
2479 * gamma handling for low bit depth.
2480 */
2481 unsigned int test_lbg :1;
2482 unsigned int test_lbg_gamma_threshold :1;
2483 unsigned int test_lbg_gamma_transform :1;
2484 unsigned int test_lbg_gamma_sbit :1;
2485 unsigned int test_lbg_gamma_composition :1;
2486
2487 unsigned int log :1; /* Log max error */
2488
2489 /* Buffer information, the buffer size limits the size of the chunks that can
2490 * be modified - they must fit (including header and CRC) into the buffer!
2491 */
2492 size_t flush; /* Count of bytes to flush */
2493 size_t buffer_count; /* Bytes in buffer */
2494 size_t buffer_position; /* Position in buffer */
2495 png_byte buffer[1024];
2496 } png_modifier;
2497
2498 /* This returns true if the test should be stopped now because it has already
2499 * failed and it is running silently.
2500 */
fail(png_modifier * pm)2501 static int fail(png_modifier *pm)
2502 {
2503 return !pm->log && !pm->this.verbose && (pm->this.nerrors > 0 ||
2504 (pm->this.treat_warnings_as_errors && pm->this.nwarnings > 0));
2505 }
2506
2507 static void
modifier_init(png_modifier * pm)2508 modifier_init(png_modifier *pm)
2509 {
2510 memset(pm, 0, sizeof *pm);
2511 store_init(&pm->this);
2512 pm->modifications = NULL;
2513 pm->state = modifier_start;
2514 pm->sbitlow = 1U;
2515 pm->ngammas = 0;
2516 pm->ngamma_tests = 0;
2517 pm->gammas = 0;
2518 pm->current_gamma = 0;
2519 pm->encodings = 0;
2520 pm->nencodings = 0;
2521 pm->current_encoding = 0;
2522 pm->encoding_counter = 0;
2523 pm->encoding_ignored = 0;
2524 pm->repeat = 0;
2525 pm->test_uses_encoding = 0;
2526 pm->maxout8 = pm->maxpc8 = pm->maxabs8 = pm->maxcalc8 = 0;
2527 pm->maxout16 = pm->maxpc16 = pm->maxabs16 = pm->maxcalc16 = 0;
2528 pm->maxcalcG = 0;
2529 pm->limit = 4E-3;
2530 pm->log8 = pm->log16 = 0; /* Means 'off' */
2531 pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
2532 pm->error_gray_16 = pm->error_color_8 = pm->error_color_16 = 0;
2533 pm->error_indexed = 0;
2534 pm->use_update_info = 0;
2535 pm->interlace_type = PNG_INTERLACE_NONE;
2536 pm->test_standard = 0;
2537 pm->test_size = 0;
2538 pm->test_transform = 0;
2539 # ifdef PNG_WRITE_tRNS_SUPPORTED
2540 pm->test_tRNS = 1;
2541 # else
2542 pm->test_tRNS = 0;
2543 # endif
2544 pm->use_input_precision = 0;
2545 pm->use_input_precision_sbit = 0;
2546 pm->use_input_precision_16to8 = 0;
2547 pm->calculations_use_input_precision = 0;
2548 pm->assume_16_bit_calculations = 0;
2549 pm->test_gamma_threshold = 0;
2550 pm->test_gamma_transform = 0;
2551 pm->test_gamma_sbit = 0;
2552 pm->test_gamma_scale16 = 0;
2553 pm->test_gamma_background = 0;
2554 pm->test_gamma_alpha_mode = 0;
2555 pm->test_gamma_expand16 = 0;
2556 pm->test_lbg = 1;
2557 pm->test_lbg_gamma_threshold = 1;
2558 pm->test_lbg_gamma_transform = 1;
2559 pm->test_lbg_gamma_sbit = 1;
2560 pm->test_lbg_gamma_composition = 1;
2561 pm->test_exhaustive = 0;
2562 pm->log = 0;
2563
2564 /* Rely on the memset for all the other fields - there are no pointers */
2565 }
2566
2567 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
2568
2569 /* This controls use of checks that explicitly know how libpng digitizes the
2570 * samples in calculations; setting this circumvents simple error limit checking
2571 * in the rgb_to_gray check, replacing it with an exact copy of the libpng 1.5
2572 * algorithm.
2573 */
2574 #define DIGITIZE PNG_LIBPNG_VER < 10700
2575
2576 /* If pm->calculations_use_input_precision is set then operations will happen
2577 * with the precision of the input, not the precision of the output depth.
2578 *
2579 * If pm->assume_16_bit_calculations is set then even 8 bit calculations use 16
2580 * bit precision. This only affects those of the following limits that pertain
2581 * to a calculation - not a digitization operation - unless the following API is
2582 * called directly.
2583 */
2584 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2585 #if DIGITIZE
digitize(double value,int depth,int do_round)2586 static double digitize(double value, int depth, int do_round)
2587 {
2588 /* 'value' is in the range 0 to 1, the result is the same value rounded to a
2589 * multiple of the digitization factor - 8 or 16 bits depending on both the
2590 * sample depth and the 'assume' setting. Digitization is normally by
2591 * rounding and 'do_round' should be 1, if it is 0 the digitized value will
2592 * be truncated.
2593 */
2594 const unsigned int digitization_factor = (1U << depth) -1;
2595
2596 /* Limiting the range is done as a convenience to the caller - it's easier to
2597 * do it once here than every time at the call site.
2598 */
2599 if (value <= 0)
2600 value = 0;
2601
2602 else if (value >= 1)
2603 value = 1;
2604
2605 value *= digitization_factor;
2606 if (do_round) value += .5;
2607 return floor(value)/digitization_factor;
2608 }
2609 #endif
2610 #endif /* RGB_TO_GRAY */
2611
2612 #ifdef PNG_READ_GAMMA_SUPPORTED
abserr(const png_modifier * pm,int in_depth,int out_depth)2613 static double abserr(const png_modifier *pm, int in_depth, int out_depth)
2614 {
2615 /* Absolute error permitted in linear values - affected by the bit depth of
2616 * the calculations.
2617 */
2618 if (pm->assume_16_bit_calculations ||
2619 (pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2620 return pm->maxabs16;
2621 else
2622 return pm->maxabs8;
2623 }
2624
calcerr(const png_modifier * pm,int in_depth,int out_depth)2625 static double calcerr(const png_modifier *pm, int in_depth, int out_depth)
2626 {
2627 /* Error in the linear composition arithmetic - only relevant when
2628 * composition actually happens (0 < alpha < 1).
2629 */
2630 if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2631 return pm->maxcalc16;
2632 else if (pm->assume_16_bit_calculations)
2633 return pm->maxcalcG;
2634 else
2635 return pm->maxcalc8;
2636 }
2637
pcerr(const png_modifier * pm,int in_depth,int out_depth)2638 static double pcerr(const png_modifier *pm, int in_depth, int out_depth)
2639 {
2640 /* Percentage error permitted in the linear values. Note that the specified
2641 * value is a percentage but this routine returns a simple number.
2642 */
2643 if (pm->assume_16_bit_calculations ||
2644 (pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2645 return pm->maxpc16 * .01;
2646 else
2647 return pm->maxpc8 * .01;
2648 }
2649
2650 /* Output error - the error in the encoded value. This is determined by the
2651 * digitization of the output so can be +/-0.5 in the actual output value. In
2652 * the expand_16 case with the current code in libpng the expand happens after
2653 * all the calculations are done in 8 bit arithmetic, so even though the output
2654 * depth is 16 the output error is determined by the 8 bit calculation.
2655 *
2656 * This limit is not determined by the bit depth of internal calculations.
2657 *
2658 * The specified parameter does *not* include the base .5 digitization error but
2659 * it is added here.
2660 */
outerr(const png_modifier * pm,int in_depth,int out_depth)2661 static double outerr(const png_modifier *pm, int in_depth, int out_depth)
2662 {
2663 /* There is a serious error in the 2 and 4 bit grayscale transform because
2664 * the gamma table value (8 bits) is simply shifted, not rounded, so the
2665 * error in 4 bit grayscale gamma is up to the value below. This is a hack
2666 * to allow pngvalid to succeed:
2667 *
2668 * TODO: fix this in libpng
2669 */
2670 if (out_depth == 2)
2671 return .73182-.5;
2672
2673 if (out_depth == 4)
2674 return .90644-.5;
2675
2676 if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2677 return pm->maxout16;
2678
2679 /* This is the case where the value was calculated at 8-bit precision then
2680 * scaled to 16 bits.
2681 */
2682 else if (out_depth == 16)
2683 return pm->maxout8 * 257;
2684
2685 else
2686 return pm->maxout8;
2687 }
2688
2689 /* This does the same thing as the above however it returns the value to log,
2690 * rather than raising a warning. This is useful for debugging to track down
2691 * exactly what set of parameters cause high error values.
2692 */
outlog(const png_modifier * pm,int in_depth,int out_depth)2693 static double outlog(const png_modifier *pm, int in_depth, int out_depth)
2694 {
2695 /* The command line parameters are either 8 bit (0..255) or 16 bit (0..65535)
2696 * and so must be adjusted for low bit depth grayscale:
2697 */
2698 if (out_depth <= 8)
2699 {
2700 if (pm->log8 == 0) /* switched off */
2701 return 256;
2702
2703 if (out_depth < 8)
2704 return pm->log8 / 255 * ((1<<out_depth)-1);
2705
2706 return pm->log8;
2707 }
2708
2709 if ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16)
2710 {
2711 if (pm->log16 == 0)
2712 return 65536;
2713
2714 return pm->log16;
2715 }
2716
2717 /* This is the case where the value was calculated at 8-bit precision then
2718 * scaled to 16 bits.
2719 */
2720 if (pm->log8 == 0)
2721 return 65536;
2722
2723 return pm->log8 * 257;
2724 }
2725
2726 /* This complements the above by providing the appropriate quantization for the
2727 * final value. Normally this would just be quantization to an integral value,
2728 * but in the 8 bit calculation case it's actually quantization to a multiple of
2729 * 257!
2730 */
output_quantization_factor(const png_modifier * pm,int in_depth,int out_depth)2731 static int output_quantization_factor(const png_modifier *pm, int in_depth,
2732 int out_depth)
2733 {
2734 if (out_depth == 16 && in_depth != 16 &&
2735 pm->calculations_use_input_precision)
2736 return 257;
2737 else
2738 return 1;
2739 }
2740 #endif /* PNG_READ_GAMMA_SUPPORTED */
2741
2742 /* One modification structure must be provided for each chunk to be modified (in
2743 * fact more than one can be provided if multiple separate changes are desired
2744 * for a single chunk.) Modifications include adding a new chunk when a
2745 * suitable chunk does not exist.
2746 *
2747 * The caller of modify_fn will reset the CRC of the chunk and record 'modified'
2748 * or 'added' as appropriate if the modify_fn returns 1 (true). If the
2749 * modify_fn is NULL the chunk is simply removed.
2750 */
2751 typedef struct png_modification
2752 {
2753 struct png_modification *next;
2754 png_uint_32 chunk;
2755
2756 /* If the following is NULL all matching chunks will be removed: */
2757 int (*modify_fn)(struct png_modifier *pm,
2758 struct png_modification *me, int add);
2759
2760 /* If the following is set to PLTE, IDAT or IEND and the chunk has not been
2761 * found and modified (and there is a modify_fn) the modify_fn will be called
2762 * to add the chunk before the relevant chunk.
2763 */
2764 png_uint_32 add;
2765 unsigned int modified :1; /* Chunk was modified */
2766 unsigned int added :1; /* Chunk was added */
2767 unsigned int removed :1; /* Chunk was removed */
2768 } png_modification;
2769
2770 static void
modification_reset(png_modification * pmm)2771 modification_reset(png_modification *pmm)
2772 {
2773 if (pmm != NULL)
2774 {
2775 pmm->modified = 0;
2776 pmm->added = 0;
2777 pmm->removed = 0;
2778 modification_reset(pmm->next);
2779 }
2780 }
2781
2782 static void
modification_init(png_modification * pmm)2783 modification_init(png_modification *pmm)
2784 {
2785 memset(pmm, 0, sizeof *pmm);
2786 pmm->next = NULL;
2787 pmm->chunk = 0;
2788 pmm->modify_fn = NULL;
2789 pmm->add = 0;
2790 modification_reset(pmm);
2791 }
2792
2793 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
2794 static void
modifier_current_encoding(const png_modifier * pm,color_encoding * ce)2795 modifier_current_encoding(const png_modifier *pm, color_encoding *ce)
2796 {
2797 if (pm->current_encoding != 0)
2798 *ce = *pm->current_encoding;
2799
2800 else
2801 memset(ce, 0, sizeof *ce);
2802
2803 ce->gamma = pm->current_gamma;
2804 }
2805 #endif
2806
2807 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
2808 static size_t
safecat_current_encoding(char * buffer,size_t bufsize,size_t pos,const png_modifier * pm)2809 safecat_current_encoding(char *buffer, size_t bufsize, size_t pos,
2810 const png_modifier *pm)
2811 {
2812 pos = safecat_color_encoding(buffer, bufsize, pos, pm->current_encoding,
2813 pm->current_gamma);
2814
2815 if (pm->encoding_ignored)
2816 pos = safecat(buffer, bufsize, pos, "[overridden]");
2817
2818 return pos;
2819 }
2820 #endif
2821
2822 /* Iterate through the usefully testable color encodings. An encoding is one
2823 * of:
2824 *
2825 * 1) Nothing (no color space, no gamma).
2826 * 2) Just a gamma value from the gamma array (including 1.0)
2827 * 3) A color space from the encodings array with the corresponding gamma.
2828 * 4) The same, but with gamma 1.0 (only really useful with 16 bit calculations)
2829 *
2830 * The iterator selects these in turn, the randomizer selects one at random,
2831 * which is used depends on the setting of the 'test_exhaustive' flag. Notice
2832 * that this function changes the colour space encoding so it must only be
2833 * called on completion of the previous test. This is what 'modifier_reset'
2834 * does, below.
2835 *
2836 * After the function has been called the 'repeat' flag will still be set; the
2837 * caller of modifier_reset must reset it at the start of each run of the test!
2838 */
2839 static unsigned int
modifier_total_encodings(const png_modifier * pm)2840 modifier_total_encodings(const png_modifier *pm)
2841 {
2842 return 1 + /* (1) nothing */
2843 pm->ngammas + /* (2) gamma values to test */
2844 pm->nencodings + /* (3) total number of encodings */
2845 /* The following test only works after the first time through the
2846 * png_modifier code because 'bit_depth' is set when the IHDR is read.
2847 * modifier_reset, below, preserves the setting until after it has called
2848 * the iterate function (also below.)
2849 *
2850 * For this reason do not rely on this function outside a call to
2851 * modifier_reset.
2852 */
2853 ((pm->bit_depth == 16 || pm->assume_16_bit_calculations) ?
2854 pm->nencodings : 0); /* (4) encodings with gamma == 1.0 */
2855 }
2856
2857 static void
modifier_encoding_iterate(png_modifier * pm)2858 modifier_encoding_iterate(png_modifier *pm)
2859 {
2860 if (!pm->repeat && /* Else something needs the current encoding again. */
2861 pm->test_uses_encoding) /* Some transform is encoding dependent */
2862 {
2863 if (pm->test_exhaustive)
2864 {
2865 if (++pm->encoding_counter >= modifier_total_encodings(pm))
2866 pm->encoding_counter = 0; /* This will stop the repeat */
2867 }
2868
2869 else
2870 {
2871 /* Not exhaustive - choose an encoding at random; generate a number in
2872 * the range 1..(max-1), so the result is always non-zero:
2873 */
2874 if (pm->encoding_counter == 0)
2875 pm->encoding_counter = random_mod(modifier_total_encodings(pm)-1)+1;
2876 else
2877 pm->encoding_counter = 0;
2878 }
2879
2880 if (pm->encoding_counter > 0)
2881 pm->repeat = 1;
2882 }
2883
2884 else if (!pm->repeat)
2885 pm->encoding_counter = 0;
2886 }
2887
2888 static void
modifier_reset(png_modifier * pm)2889 modifier_reset(png_modifier *pm)
2890 {
2891 store_read_reset(&pm->this);
2892 pm->limit = 4E-3;
2893 pm->pending_len = pm->pending_chunk = 0;
2894 pm->flush = pm->buffer_count = pm->buffer_position = 0;
2895 pm->modifications = NULL;
2896 pm->state = modifier_start;
2897 modifier_encoding_iterate(pm);
2898 /* The following must be set in the next run. In particular
2899 * test_uses_encodings must be set in the _ini function of each transform
2900 * that looks at the encodings. (Not the 'add' function!)
2901 */
2902 pm->test_uses_encoding = 0;
2903 pm->current_gamma = 0;
2904 pm->current_encoding = 0;
2905 pm->encoding_ignored = 0;
2906 /* These only become value after IHDR is read: */
2907 pm->bit_depth = pm->colour_type = 0;
2908 }
2909
2910 /* The following must be called before anything else to get the encoding set up
2911 * on the modifier. In particular it must be called before the transform init
2912 * functions are called.
2913 */
2914 static void
modifier_set_encoding(png_modifier * pm)2915 modifier_set_encoding(png_modifier *pm)
2916 {
2917 /* Set the encoding to the one specified by the current encoding counter,
2918 * first clear out all the settings - this corresponds to an encoding_counter
2919 * of 0.
2920 */
2921 pm->current_gamma = 0;
2922 pm->current_encoding = 0;
2923 pm->encoding_ignored = 0; /* not ignored yet - happens in _ini functions. */
2924
2925 /* Now, if required, set the gamma and encoding fields. */
2926 if (pm->encoding_counter > 0)
2927 {
2928 /* The gammas[] array is an array of screen gammas, not encoding gammas,
2929 * so we need the inverse:
2930 */
2931 if (pm->encoding_counter <= pm->ngammas)
2932 pm->current_gamma = 1/pm->gammas[pm->encoding_counter-1];
2933
2934 else
2935 {
2936 unsigned int i = pm->encoding_counter - pm->ngammas;
2937
2938 if (i >= pm->nencodings)
2939 {
2940 i %= pm->nencodings;
2941 pm->current_gamma = 1; /* Linear, only in the 16 bit case */
2942 }
2943
2944 else
2945 pm->current_gamma = pm->encodings[i].gamma;
2946
2947 pm->current_encoding = pm->encodings + i;
2948 }
2949 }
2950 }
2951
2952 /* Enquiry functions to find out what is set. Notice that there is an implicit
2953 * assumption below that the first encoding in the list is the one for sRGB.
2954 */
2955 static int
modifier_color_encoding_is_sRGB(const png_modifier * pm)2956 modifier_color_encoding_is_sRGB(const png_modifier *pm)
2957 {
2958 return pm->current_encoding != 0 && pm->current_encoding == pm->encodings &&
2959 pm->current_encoding->gamma == pm->current_gamma;
2960 }
2961
2962 static int
modifier_color_encoding_is_set(const png_modifier * pm)2963 modifier_color_encoding_is_set(const png_modifier *pm)
2964 {
2965 return pm->current_gamma != 0;
2966 }
2967
2968 /* The guts of modification are performed during a read. */
2969 static void
modifier_crc(png_bytep buffer)2970 modifier_crc(png_bytep buffer)
2971 {
2972 /* Recalculate the chunk CRC - a complete chunk must be in
2973 * the buffer, at the start.
2974 */
2975 uInt datalen = png_get_uint_32(buffer);
2976 uLong crc = crc32(0, buffer+4, datalen+4);
2977 /* The cast to png_uint_32 is safe because a crc32 is always a 32 bit value.
2978 */
2979 png_save_uint_32(buffer+datalen+8, (png_uint_32)crc);
2980 }
2981
2982 static void
modifier_setbuffer(png_modifier * pm)2983 modifier_setbuffer(png_modifier *pm)
2984 {
2985 modifier_crc(pm->buffer);
2986 pm->buffer_count = png_get_uint_32(pm->buffer)+12;
2987 pm->buffer_position = 0;
2988 }
2989
2990 /* Separate the callback into the actual implementation (which is passed the
2991 * png_modifier explicitly) and the callback, which gets the modifier from the
2992 * png_struct.
2993 */
2994 static void
modifier_read_imp(png_modifier * pm,png_bytep pb,png_size_t st)2995 modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
2996 {
2997 while (st > 0)
2998 {
2999 size_t cb;
3000 png_uint_32 len, chunk;
3001 png_modification *mod;
3002
3003 if (pm->buffer_position >= pm->buffer_count) switch (pm->state)
3004 {
3005 static png_byte sign[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
3006 case modifier_start:
3007 store_read_chunk(&pm->this, pm->buffer, 8, 8); /* signature. */
3008 pm->buffer_count = 8;
3009 pm->buffer_position = 0;
3010
3011 if (memcmp(pm->buffer, sign, 8) != 0)
3012 png_error(pm->this.pread, "invalid PNG file signature");
3013 pm->state = modifier_signature;
3014 break;
3015
3016 case modifier_signature:
3017 store_read_chunk(&pm->this, pm->buffer, 13+12, 13+12); /* IHDR */
3018 pm->buffer_count = 13+12;
3019 pm->buffer_position = 0;
3020
3021 if (png_get_uint_32(pm->buffer) != 13 ||
3022 png_get_uint_32(pm->buffer+4) != CHUNK_IHDR)
3023 png_error(pm->this.pread, "invalid IHDR");
3024
3025 /* Check the list of modifiers for modifications to the IHDR. */
3026 mod = pm->modifications;
3027 while (mod != NULL)
3028 {
3029 if (mod->chunk == CHUNK_IHDR && mod->modify_fn &&
3030 (*mod->modify_fn)(pm, mod, 0))
3031 {
3032 mod->modified = 1;
3033 modifier_setbuffer(pm);
3034 }
3035
3036 /* Ignore removal or add if IHDR! */
3037 mod = mod->next;
3038 }
3039
3040 /* Cache information from the IHDR (the modified one.) */
3041 pm->bit_depth = pm->buffer[8+8];
3042 pm->colour_type = pm->buffer[8+8+1];
3043
3044 pm->state = modifier_IHDR;
3045 pm->flush = 0;
3046 break;
3047
3048 case modifier_IHDR:
3049 default:
3050 /* Read a new chunk and process it until we see PLTE, IDAT or
3051 * IEND. 'flush' indicates that there is still some data to
3052 * output from the preceding chunk.
3053 */
3054 if ((cb = pm->flush) > 0)
3055 {
3056 if (cb > st) cb = st;
3057 pm->flush -= cb;
3058 store_read_chunk(&pm->this, pb, cb, cb);
3059 pb += cb;
3060 st -= cb;
3061 if (st == 0) return;
3062 }
3063
3064 /* No more bytes to flush, read a header, or handle a pending
3065 * chunk.
3066 */
3067 if (pm->pending_chunk != 0)
3068 {
3069 png_save_uint_32(pm->buffer, pm->pending_len);
3070 png_save_uint_32(pm->buffer+4, pm->pending_chunk);
3071 pm->pending_len = 0;
3072 pm->pending_chunk = 0;
3073 }
3074 else
3075 store_read_chunk(&pm->this, pm->buffer, 8, 8);
3076
3077 pm->buffer_count = 8;
3078 pm->buffer_position = 0;
3079
3080 /* Check for something to modify or a terminator chunk. */
3081 len = png_get_uint_32(pm->buffer);
3082 chunk = png_get_uint_32(pm->buffer+4);
3083
3084 /* Terminators first, they may have to be delayed for added
3085 * chunks
3086 */
3087 if (chunk == CHUNK_PLTE || chunk == CHUNK_IDAT ||
3088 chunk == CHUNK_IEND)
3089 {
3090 mod = pm->modifications;
3091
3092 while (mod != NULL)
3093 {
3094 if ((mod->add == chunk ||
3095 (mod->add == CHUNK_PLTE && chunk == CHUNK_IDAT)) &&
3096 mod->modify_fn != NULL && !mod->modified && !mod->added)
3097 {
3098 /* Regardless of what the modify function does do not run
3099 * this again.
3100 */
3101 mod->added = 1;
3102
3103 if ((*mod->modify_fn)(pm, mod, 1 /*add*/))
3104 {
3105 /* Reset the CRC on a new chunk */
3106 if (pm->buffer_count > 0)
3107 modifier_setbuffer(pm);
3108
3109 else
3110 {
3111 pm->buffer_position = 0;
3112 mod->removed = 1;
3113 }
3114
3115 /* The buffer has been filled with something (we assume)
3116 * so output this. Pend the current chunk.
3117 */
3118 pm->pending_len = len;
3119 pm->pending_chunk = chunk;
3120 break; /* out of while */
3121 }
3122 }
3123
3124 mod = mod->next;
3125 }
3126
3127 /* Don't do any further processing if the buffer was modified -
3128 * otherwise the code will end up modifying a chunk that was
3129 * just added.
3130 */
3131 if (mod != NULL)
3132 break; /* out of switch */
3133 }
3134
3135 /* If we get to here then this chunk may need to be modified. To
3136 * do this it must be less than 1024 bytes in total size, otherwise
3137 * it just gets flushed.
3138 */
3139 if (len+12 <= sizeof pm->buffer)
3140 {
3141 png_size_t s = len+12-pm->buffer_count;
3142 store_read_chunk(&pm->this, pm->buffer+pm->buffer_count, s, s);
3143 pm->buffer_count = len+12;
3144
3145 /* Check for a modification, else leave it be. */
3146 mod = pm->modifications;
3147 while (mod != NULL)
3148 {
3149 if (mod->chunk == chunk)
3150 {
3151 if (mod->modify_fn == NULL)
3152 {
3153 /* Remove this chunk */
3154 pm->buffer_count = pm->buffer_position = 0;
3155 mod->removed = 1;
3156 break; /* Terminate the while loop */
3157 }
3158
3159 else if ((*mod->modify_fn)(pm, mod, 0))
3160 {
3161 mod->modified = 1;
3162 /* The chunk may have been removed: */
3163 if (pm->buffer_count == 0)
3164 {
3165 pm->buffer_position = 0;
3166 break;
3167 }
3168 modifier_setbuffer(pm);
3169 }
3170 }
3171
3172 mod = mod->next;
3173 }
3174 }
3175
3176 else
3177 pm->flush = len+12 - pm->buffer_count; /* data + crc */
3178
3179 /* Take the data from the buffer (if there is any). */
3180 break;
3181 }
3182
3183 /* Here to read from the modifier buffer (not directly from
3184 * the store, as in the flush case above.)
3185 */
3186 cb = pm->buffer_count - pm->buffer_position;
3187
3188 if (cb > st)
3189 cb = st;
3190
3191 memcpy(pb, pm->buffer + pm->buffer_position, cb);
3192 st -= cb;
3193 pb += cb;
3194 pm->buffer_position += cb;
3195 }
3196 }
3197
3198 /* The callback: */
3199 static void PNGCBAPI
modifier_read(png_structp ppIn,png_bytep pb,png_size_t st)3200 modifier_read(png_structp ppIn, png_bytep pb, png_size_t st)
3201 {
3202 png_const_structp pp = ppIn;
3203 png_modifier *pm = voidcast(png_modifier*, png_get_io_ptr(pp));
3204
3205 if (pm == NULL || pm->this.pread != pp)
3206 png_error(pp, "bad modifier_read call");
3207
3208 modifier_read_imp(pm, pb, st);
3209 }
3210
3211 /* Like store_progressive_read but the data is getting changed as we go so we
3212 * need a local buffer.
3213 */
3214 static void
modifier_progressive_read(png_modifier * pm,png_structp pp,png_infop pi)3215 modifier_progressive_read(png_modifier *pm, png_structp pp, png_infop pi)
3216 {
3217 if (pm->this.pread != pp || pm->this.current == NULL ||
3218 pm->this.next == NULL)
3219 png_error(pp, "store state damaged (progressive)");
3220
3221 /* This is another Horowitz and Hill random noise generator. In this case
3222 * the aim is to stress the progressive reader with truly horrible variable
3223 * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
3224 * is generated. We could probably just count from 1 to 32767 and get as
3225 * good a result.
3226 */
3227 for (;;)
3228 {
3229 static png_uint_32 noise = 1;
3230 png_size_t cb, cbAvail;
3231 png_byte buffer[512];
3232
3233 /* Generate 15 more bits of stuff: */
3234 noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
3235 cb = noise & 0x1ff;
3236
3237 /* Check that this number of bytes are available (in the current buffer.)
3238 * (This doesn't quite work - the modifier might delete a chunk; unlikely
3239 * but possible, it doesn't happen at present because the modifier only
3240 * adds chunks to standard images.)
3241 */
3242 cbAvail = store_read_buffer_avail(&pm->this);
3243 if (pm->buffer_count > pm->buffer_position)
3244 cbAvail += pm->buffer_count - pm->buffer_position;
3245
3246 if (cb > cbAvail)
3247 {
3248 /* Check for EOF: */
3249 if (cbAvail == 0)
3250 break;
3251
3252 cb = cbAvail;
3253 }
3254
3255 modifier_read_imp(pm, buffer, cb);
3256 png_process_data(pp, pi, buffer, cb);
3257 }
3258
3259 /* Check the invariants at the end (if this fails it's a problem in this
3260 * file!)
3261 */
3262 if (pm->buffer_count > pm->buffer_position ||
3263 pm->this.next != &pm->this.current->data ||
3264 pm->this.readpos < pm->this.current->datacount)
3265 png_error(pp, "progressive read implementation error");
3266 }
3267
3268 /* Set up a modifier. */
3269 static png_structp
set_modifier_for_read(png_modifier * pm,png_infopp ppi,png_uint_32 id,const char * name)3270 set_modifier_for_read(png_modifier *pm, png_infopp ppi, png_uint_32 id,
3271 const char *name)
3272 {
3273 /* Do this first so that the modifier fields are cleared even if an error
3274 * happens allocating the png_struct. No allocation is done here so no
3275 * cleanup is required.
3276 */
3277 pm->state = modifier_start;
3278 pm->bit_depth = 0;
3279 pm->colour_type = 255;
3280
3281 pm->pending_len = 0;
3282 pm->pending_chunk = 0;
3283 pm->flush = 0;
3284 pm->buffer_count = 0;
3285 pm->buffer_position = 0;
3286
3287 return set_store_for_read(&pm->this, ppi, id, name);
3288 }
3289
3290
3291 /******************************** MODIFICATIONS *******************************/
3292 /* Standard modifications to add chunks. These do not require the _SUPPORTED
3293 * macros because the chunks can be there regardless of whether this specific
3294 * libpng supports them.
3295 */
3296 typedef struct gama_modification
3297 {
3298 png_modification this;
3299 png_fixed_point gamma;
3300 } gama_modification;
3301
3302 static int
gama_modify(png_modifier * pm,png_modification * me,int add)3303 gama_modify(png_modifier *pm, png_modification *me, int add)
3304 {
3305 UNUSED(add)
3306 /* This simply dumps the given gamma value into the buffer. */
3307 png_save_uint_32(pm->buffer, 4);
3308 png_save_uint_32(pm->buffer+4, CHUNK_gAMA);
3309 png_save_uint_32(pm->buffer+8, ((gama_modification*)me)->gamma);
3310 return 1;
3311 }
3312
3313 static void
gama_modification_init(gama_modification * me,png_modifier * pm,double gammad)3314 gama_modification_init(gama_modification *me, png_modifier *pm, double gammad)
3315 {
3316 double g;
3317
3318 modification_init(&me->this);
3319 me->this.chunk = CHUNK_gAMA;
3320 me->this.modify_fn = gama_modify;
3321 me->this.add = CHUNK_PLTE;
3322 g = fix(gammad);
3323 me->gamma = (png_fixed_point)g;
3324 me->this.next = pm->modifications;
3325 pm->modifications = &me->this;
3326 }
3327
3328 typedef struct chrm_modification
3329 {
3330 png_modification this;
3331 const color_encoding *encoding;
3332 png_fixed_point wx, wy, rx, ry, gx, gy, bx, by;
3333 } chrm_modification;
3334
3335 static int
chrm_modify(png_modifier * pm,png_modification * me,int add)3336 chrm_modify(png_modifier *pm, png_modification *me, int add)
3337 {
3338 UNUSED(add)
3339 /* As with gAMA this just adds the required cHRM chunk to the buffer. */
3340 png_save_uint_32(pm->buffer , 32);
3341 png_save_uint_32(pm->buffer+ 4, CHUNK_cHRM);
3342 png_save_uint_32(pm->buffer+ 8, ((chrm_modification*)me)->wx);
3343 png_save_uint_32(pm->buffer+12, ((chrm_modification*)me)->wy);
3344 png_save_uint_32(pm->buffer+16, ((chrm_modification*)me)->rx);
3345 png_save_uint_32(pm->buffer+20, ((chrm_modification*)me)->ry);
3346 png_save_uint_32(pm->buffer+24, ((chrm_modification*)me)->gx);
3347 png_save_uint_32(pm->buffer+28, ((chrm_modification*)me)->gy);
3348 png_save_uint_32(pm->buffer+32, ((chrm_modification*)me)->bx);
3349 png_save_uint_32(pm->buffer+36, ((chrm_modification*)me)->by);
3350 return 1;
3351 }
3352
3353 static void
chrm_modification_init(chrm_modification * me,png_modifier * pm,const color_encoding * encoding)3354 chrm_modification_init(chrm_modification *me, png_modifier *pm,
3355 const color_encoding *encoding)
3356 {
3357 CIE_color white = white_point(encoding);
3358
3359 /* Original end points: */
3360 me->encoding = encoding;
3361
3362 /* Chromaticities (in fixed point): */
3363 me->wx = fix(chromaticity_x(white));
3364 me->wy = fix(chromaticity_y(white));
3365
3366 me->rx = fix(chromaticity_x(encoding->red));
3367 me->ry = fix(chromaticity_y(encoding->red));
3368 me->gx = fix(chromaticity_x(encoding->green));
3369 me->gy = fix(chromaticity_y(encoding->green));
3370 me->bx = fix(chromaticity_x(encoding->blue));
3371 me->by = fix(chromaticity_y(encoding->blue));
3372
3373 modification_init(&me->this);
3374 me->this.chunk = CHUNK_cHRM;
3375 me->this.modify_fn = chrm_modify;
3376 me->this.add = CHUNK_PLTE;
3377 me->this.next = pm->modifications;
3378 pm->modifications = &me->this;
3379 }
3380
3381 typedef struct srgb_modification
3382 {
3383 png_modification this;
3384 png_byte intent;
3385 } srgb_modification;
3386
3387 static int
srgb_modify(png_modifier * pm,png_modification * me,int add)3388 srgb_modify(png_modifier *pm, png_modification *me, int add)
3389 {
3390 UNUSED(add)
3391 /* As above, ignore add and just make a new chunk */
3392 png_save_uint_32(pm->buffer, 1);
3393 png_save_uint_32(pm->buffer+4, CHUNK_sRGB);
3394 pm->buffer[8] = ((srgb_modification*)me)->intent;
3395 return 1;
3396 }
3397
3398 static void
srgb_modification_init(srgb_modification * me,png_modifier * pm,png_byte intent)3399 srgb_modification_init(srgb_modification *me, png_modifier *pm, png_byte intent)
3400 {
3401 modification_init(&me->this);
3402 me->this.chunk = CHUNK_sBIT;
3403
3404 if (intent <= 3) /* if valid, else *delete* sRGB chunks */
3405 {
3406 me->this.modify_fn = srgb_modify;
3407 me->this.add = CHUNK_PLTE;
3408 me->intent = intent;
3409 }
3410
3411 else
3412 {
3413 me->this.modify_fn = 0;
3414 me->this.add = 0;
3415 me->intent = 0;
3416 }
3417
3418 me->this.next = pm->modifications;
3419 pm->modifications = &me->this;
3420 }
3421
3422 #ifdef PNG_READ_GAMMA_SUPPORTED
3423 typedef struct sbit_modification
3424 {
3425 png_modification this;
3426 png_byte sbit;
3427 } sbit_modification;
3428
3429 static int
sbit_modify(png_modifier * pm,png_modification * me,int add)3430 sbit_modify(png_modifier *pm, png_modification *me, int add)
3431 {
3432 png_byte sbit = ((sbit_modification*)me)->sbit;
3433 if (pm->bit_depth > sbit)
3434 {
3435 int cb = 0;
3436 switch (pm->colour_type)
3437 {
3438 case 0:
3439 cb = 1;
3440 break;
3441
3442 case 2:
3443 case 3:
3444 cb = 3;
3445 break;
3446
3447 case 4:
3448 cb = 2;
3449 break;
3450
3451 case 6:
3452 cb = 4;
3453 break;
3454
3455 default:
3456 png_error(pm->this.pread,
3457 "unexpected colour type in sBIT modification");
3458 }
3459
3460 png_save_uint_32(pm->buffer, cb);
3461 png_save_uint_32(pm->buffer+4, CHUNK_sBIT);
3462
3463 while (cb > 0)
3464 (pm->buffer+8)[--cb] = sbit;
3465
3466 return 1;
3467 }
3468 else if (!add)
3469 {
3470 /* Remove the sBIT chunk */
3471 pm->buffer_count = pm->buffer_position = 0;
3472 return 1;
3473 }
3474 else
3475 return 0; /* do nothing */
3476 }
3477
3478 static void
sbit_modification_init(sbit_modification * me,png_modifier * pm,png_byte sbit)3479 sbit_modification_init(sbit_modification *me, png_modifier *pm, png_byte sbit)
3480 {
3481 modification_init(&me->this);
3482 me->this.chunk = CHUNK_sBIT;
3483 me->this.modify_fn = sbit_modify;
3484 me->this.add = CHUNK_PLTE;
3485 me->sbit = sbit;
3486 me->this.next = pm->modifications;
3487 pm->modifications = &me->this;
3488 }
3489 #endif /* PNG_READ_GAMMA_SUPPORTED */
3490 #endif /* PNG_READ_TRANSFORMS_SUPPORTED */
3491
3492 /***************************** STANDARD PNG FILES *****************************/
3493 /* Standard files - write and save standard files. */
3494 /* There are two basic forms of standard images. Those which attempt to have
3495 * all the possible pixel values (not possible for 16bpp images, but a range of
3496 * values are produced) and those which have a range of image sizes. The former
3497 * are used for testing transforms, in particular gamma correction and bit
3498 * reduction and increase. The latter are reserved for testing the behavior of
3499 * libpng with respect to 'odd' image sizes - particularly small images where
3500 * rows become 1 byte and interlace passes disappear.
3501 *
3502 * The first, most useful, set are the 'transform' images, the second set of
3503 * small images are the 'size' images.
3504 *
3505 * The transform files are constructed with rows which fit into a 1024 byte row
3506 * buffer. This makes allocation easier below. Further regardless of the file
3507 * format every row has 128 pixels (giving 1024 bytes for 64bpp formats).
3508 *
3509 * Files are stored with no gAMA or sBIT chunks, with a PLTE only when needed
3510 * and with an ID derived from the colour type, bit depth and interlace type
3511 * as above (FILEID). The width (128) and height (variable) are not stored in
3512 * the FILEID - instead the fields are set to 0, indicating a transform file.
3513 *
3514 * The size files ar constructed with rows a maximum of 128 bytes wide, allowing
3515 * a maximum width of 16 pixels (for the 64bpp case.) They also have a maximum
3516 * height of 16 rows. The width and height are stored in the FILEID and, being
3517 * non-zero, indicate a size file.
3518 *
3519 * Because the PNG filter code is typically the largest CPU consumer within
3520 * libpng itself there is a tendency to attempt to optimize it. This results in
3521 * special case code which needs to be validated. To cause this to happen the
3522 * 'size' images are made to use each possible filter, in so far as this is
3523 * possible for smaller images.
3524 *
3525 * For palette image (colour type 3) multiple transform images are stored with
3526 * the same bit depth to allow testing of more colour combinations -
3527 * particularly important for testing the gamma code because libpng uses a
3528 * different code path for palette images. For size images a single palette is
3529 * used.
3530 */
3531
3532 /* Make a 'standard' palette. Because there are only 256 entries in a palette
3533 * (maximum) this actually makes a random palette in the hope that enough tests
3534 * will catch enough errors. (Note that the same palette isn't produced every
3535 * time for the same test - it depends on what previous tests have been run -
3536 * but a given set of arguments to pngvalid will always produce the same palette
3537 * at the same test! This is why pseudo-random number generators are useful for
3538 * testing.)
3539 *
3540 * The store must be open for write when this is called, otherwise an internal
3541 * error will occur. This routine contains its own magic number seed, so the
3542 * palettes generated don't change if there are intervening errors (changing the
3543 * calls to the store_mark seed.)
3544 */
3545 static store_palette_entry *
make_standard_palette(png_store * ps,int npalette,int do_tRNS)3546 make_standard_palette(png_store* ps, int npalette, int do_tRNS)
3547 {
3548 static png_uint_32 palette_seed[2] = { 0x87654321, 9 };
3549
3550 int i = 0;
3551 png_byte values[256][4];
3552
3553 /* Always put in black and white plus the six primary and secondary colors.
3554 */
3555 for (; i<8; ++i)
3556 {
3557 values[i][1] = (png_byte)((i&1) ? 255U : 0U);
3558 values[i][2] = (png_byte)((i&2) ? 255U : 0U);
3559 values[i][3] = (png_byte)((i&4) ? 255U : 0U);
3560 }
3561
3562 /* Then add 62 grays (one quarter of the remaining 256 slots). */
3563 {
3564 int j = 0;
3565 png_byte random_bytes[4];
3566 png_byte need[256];
3567
3568 need[0] = 0; /*got black*/
3569 memset(need+1, 1, (sizeof need)-2); /*need these*/
3570 need[255] = 0; /*but not white*/
3571
3572 while (i<70)
3573 {
3574 png_byte b;
3575
3576 if (j==0)
3577 {
3578 make_four_random_bytes(palette_seed, random_bytes);
3579 j = 4;
3580 }
3581
3582 b = random_bytes[--j];
3583 if (need[b])
3584 {
3585 values[i][1] = b;
3586 values[i][2] = b;
3587 values[i++][3] = b;
3588 }
3589 }
3590 }
3591
3592 /* Finally add 192 colors at random - don't worry about matches to things we
3593 * already have, chance is less than 1/65536. Don't worry about grays,
3594 * chance is the same, so we get a duplicate or extra gray less than 1 time
3595 * in 170.
3596 */
3597 for (; i<256; ++i)
3598 make_four_random_bytes(palette_seed, values[i]);
3599
3600 /* Fill in the alpha values in the first byte. Just use all possible values
3601 * (0..255) in an apparently random order:
3602 */
3603 {
3604 store_palette_entry *palette;
3605 png_byte selector[4];
3606
3607 make_four_random_bytes(palette_seed, selector);
3608
3609 if (do_tRNS)
3610 for (i=0; i<256; ++i)
3611 values[i][0] = (png_byte)(i ^ selector[0]);
3612
3613 else
3614 for (i=0; i<256; ++i)
3615 values[i][0] = 255; /* no transparency/tRNS chunk */
3616
3617 /* 'values' contains 256 ARGB values, but we only need 'npalette'.
3618 * 'npalette' will always be a power of 2: 2, 4, 16 or 256. In the low
3619 * bit depth cases select colors at random, else it is difficult to have
3620 * a set of low bit depth palette test with any chance of a reasonable
3621 * range of colors. Do this by randomly permuting values into the low
3622 * 'npalette' entries using an XOR mask generated here. This also
3623 * permutes the npalette == 256 case in a potentially useful way (there is
3624 * no relationship between palette index and the color value therein!)
3625 */
3626 palette = store_write_palette(ps, npalette);
3627
3628 for (i=0; i<npalette; ++i)
3629 {
3630 palette[i].alpha = values[i ^ selector[1]][0];
3631 palette[i].red = values[i ^ selector[1]][1];
3632 palette[i].green = values[i ^ selector[1]][2];
3633 palette[i].blue = values[i ^ selector[1]][3];
3634 }
3635
3636 return palette;
3637 }
3638 }
3639
3640 /* Initialize a standard palette on a write stream. The 'do_tRNS' argument
3641 * indicates whether or not to also set the tRNS chunk.
3642 */
3643 /* TODO: the png_structp here can probably be 'const' in the future */
3644 static void
init_standard_palette(png_store * ps,png_structp pp,png_infop pi,int npalette,int do_tRNS)3645 init_standard_palette(png_store *ps, png_structp pp, png_infop pi, int npalette,
3646 int do_tRNS)
3647 {
3648 store_palette_entry *ppal = make_standard_palette(ps, npalette, do_tRNS);
3649
3650 {
3651 int i;
3652 png_color palette[256];
3653
3654 /* Set all entries to detect overread errors. */
3655 for (i=0; i<npalette; ++i)
3656 {
3657 palette[i].red = ppal[i].red;
3658 palette[i].green = ppal[i].green;
3659 palette[i].blue = ppal[i].blue;
3660 }
3661
3662 /* Just in case fill in the rest with detectable values: */
3663 for (; i<256; ++i)
3664 palette[i].red = palette[i].green = palette[i].blue = 42;
3665
3666 png_set_PLTE(pp, pi, palette, npalette);
3667 }
3668
3669 if (do_tRNS)
3670 {
3671 int i, j;
3672 png_byte tRNS[256];
3673
3674 /* Set all the entries, but skip trailing opaque entries */
3675 for (i=j=0; i<npalette; ++i)
3676 if ((tRNS[i] = ppal[i].alpha) < 255)
3677 j = i+1;
3678
3679 /* Fill in the remainder with a detectable value: */
3680 for (; i<256; ++i)
3681 tRNS[i] = 24;
3682
3683 #ifdef PNG_WRITE_tRNS_SUPPORTED
3684 if (j > 0)
3685 png_set_tRNS(pp, pi, tRNS, j, 0/*color*/);
3686 #endif
3687 }
3688 }
3689
3690 #ifdef PNG_WRITE_tRNS_SUPPORTED
3691 static void
set_random_tRNS(png_structp pp,png_infop pi,const png_byte colour_type,const int bit_depth)3692 set_random_tRNS(png_structp pp, png_infop pi, const png_byte colour_type,
3693 const int bit_depth)
3694 {
3695 /* To make this useful the tRNS color needs to match at least one pixel.
3696 * Random values are fine for gray, including the 16-bit case where we know
3697 * that the test image contains all the gray values. For RGB we need more
3698 * method as only 65536 different RGB values are generated.
3699 */
3700 png_color_16 tRNS;
3701 const png_uint_16 mask = (png_uint_16)((1U << bit_depth)-1);
3702
3703 R8(tRNS); /* makes unset fields random */
3704
3705 if (colour_type & 2/*RGB*/)
3706 {
3707 if (bit_depth == 8)
3708 {
3709 tRNS.red = random_u16();
3710 tRNS.green = random_u16();
3711 tRNS.blue = tRNS.red ^ tRNS.green;
3712 tRNS.red &= mask;
3713 tRNS.green &= mask;
3714 tRNS.blue &= mask;
3715 }
3716
3717 else /* bit_depth == 16 */
3718 {
3719 tRNS.red = random_u16();
3720 tRNS.green = (png_uint_16)(tRNS.red * 257);
3721 tRNS.blue = (png_uint_16)(tRNS.green * 17);
3722 }
3723 }
3724
3725 else
3726 {
3727 tRNS.gray = random_u16();
3728 tRNS.gray &= mask;
3729 }
3730
3731 png_set_tRNS(pp, pi, NULL, 0, &tRNS);
3732 }
3733 #endif
3734
3735 /* The number of passes is related to the interlace type. There was no libpng
3736 * API to determine this prior to 1.5, so we need an inquiry function:
3737 */
3738 static int
npasses_from_interlace_type(png_const_structp pp,int interlace_type)3739 npasses_from_interlace_type(png_const_structp pp, int interlace_type)
3740 {
3741 switch (interlace_type)
3742 {
3743 default:
3744 png_error(pp, "invalid interlace type");
3745
3746 case PNG_INTERLACE_NONE:
3747 return 1;
3748
3749 case PNG_INTERLACE_ADAM7:
3750 return PNG_INTERLACE_ADAM7_PASSES;
3751 }
3752 }
3753
3754 static unsigned int
bit_size(png_const_structp pp,png_byte colour_type,png_byte bit_depth)3755 bit_size(png_const_structp pp, png_byte colour_type, png_byte bit_depth)
3756 {
3757 switch (colour_type)
3758 {
3759 default: png_error(pp, "invalid color type");
3760
3761 case 0: return bit_depth;
3762
3763 case 2: return 3*bit_depth;
3764
3765 case 3: return bit_depth;
3766
3767 case 4: return 2*bit_depth;
3768
3769 case 6: return 4*bit_depth;
3770 }
3771 }
3772
3773 #define TRANSFORM_WIDTH 128U
3774 #define TRANSFORM_ROWMAX (TRANSFORM_WIDTH*8U)
3775 #define SIZE_ROWMAX (16*8U) /* 16 pixels, max 8 bytes each - 128 bytes */
3776 #define STANDARD_ROWMAX TRANSFORM_ROWMAX /* The larger of the two */
3777 #define SIZE_HEIGHTMAX 16 /* Maximum range of size images */
3778
3779 static size_t
transform_rowsize(png_const_structp pp,png_byte colour_type,png_byte bit_depth)3780 transform_rowsize(png_const_structp pp, png_byte colour_type,
3781 png_byte bit_depth)
3782 {
3783 return (TRANSFORM_WIDTH * bit_size(pp, colour_type, bit_depth)) / 8;
3784 }
3785
3786 /* transform_width(pp, colour_type, bit_depth) current returns the same number
3787 * every time, so just use a macro:
3788 */
3789 #define transform_width(pp, colour_type, bit_depth) TRANSFORM_WIDTH
3790
3791 static png_uint_32
transform_height(png_const_structp pp,png_byte colour_type,png_byte bit_depth)3792 transform_height(png_const_structp pp, png_byte colour_type, png_byte bit_depth)
3793 {
3794 switch (bit_size(pp, colour_type, bit_depth))
3795 {
3796 case 1:
3797 case 2:
3798 case 4:
3799 return 1; /* Total of 128 pixels */
3800
3801 case 8:
3802 return 2; /* Total of 256 pixels/bytes */
3803
3804 case 16:
3805 return 512; /* Total of 65536 pixels */
3806
3807 case 24:
3808 case 32:
3809 return 512; /* 65536 pixels */
3810
3811 case 48:
3812 case 64:
3813 return 2048;/* 4 x 65536 pixels. */
3814 # define TRANSFORM_HEIGHTMAX 2048
3815
3816 default:
3817 return 0; /* Error, will be caught later */
3818 }
3819 }
3820
3821 #ifdef PNG_READ_SUPPORTED
3822 /* The following can only be defined here, now we have the definitions
3823 * of the transform image sizes.
3824 */
3825 static png_uint_32
standard_width(png_const_structp pp,png_uint_32 id)3826 standard_width(png_const_structp pp, png_uint_32 id)
3827 {
3828 png_uint_32 width = WIDTH_FROM_ID(id);
3829 UNUSED(pp)
3830
3831 if (width == 0)
3832 width = transform_width(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
3833
3834 return width;
3835 }
3836
3837 static png_uint_32
standard_height(png_const_structp pp,png_uint_32 id)3838 standard_height(png_const_structp pp, png_uint_32 id)
3839 {
3840 png_uint_32 height = HEIGHT_FROM_ID(id);
3841
3842 if (height == 0)
3843 height = transform_height(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
3844
3845 return height;
3846 }
3847
3848 static png_uint_32
standard_rowsize(png_const_structp pp,png_uint_32 id)3849 standard_rowsize(png_const_structp pp, png_uint_32 id)
3850 {
3851 png_uint_32 width = standard_width(pp, id);
3852
3853 /* This won't overflow: */
3854 width *= bit_size(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
3855 return (width + 7) / 8;
3856 }
3857 #endif /* PNG_READ_SUPPORTED */
3858
3859 static void
transform_row(png_const_structp pp,png_byte buffer[TRANSFORM_ROWMAX],png_byte colour_type,png_byte bit_depth,png_uint_32 y)3860 transform_row(png_const_structp pp, png_byte buffer[TRANSFORM_ROWMAX],
3861 png_byte colour_type, png_byte bit_depth, png_uint_32 y)
3862 {
3863 png_uint_32 v = y << 7;
3864 png_uint_32 i = 0;
3865
3866 switch (bit_size(pp, colour_type, bit_depth))
3867 {
3868 case 1:
3869 while (i<128/8) buffer[i] = (png_byte)(v & 0xff), v += 17, ++i;
3870 return;
3871
3872 case 2:
3873 while (i<128/4) buffer[i] = (png_byte)(v & 0xff), v += 33, ++i;
3874 return;
3875
3876 case 4:
3877 while (i<128/2) buffer[i] = (png_byte)(v & 0xff), v += 65, ++i;
3878 return;
3879
3880 case 8:
3881 /* 256 bytes total, 128 bytes in each row set as follows: */
3882 while (i<128) buffer[i] = (png_byte)(v & 0xff), ++v, ++i;
3883 return;
3884
3885 case 16:
3886 /* Generate all 65536 pixel values in order, which includes the 8 bit
3887 * GA case as well as the 16 bit G case.
3888 */
3889 while (i<128)
3890 {
3891 buffer[2*i] = (png_byte)((v>>8) & 0xff);
3892 buffer[2*i+1] = (png_byte)(v & 0xff);
3893 ++v;
3894 ++i;
3895 }
3896
3897 return;
3898
3899 case 24:
3900 /* 65535 pixels, but rotate the values. */
3901 while (i<128)
3902 {
3903 /* Three bytes per pixel, r, g, b, make b by r^g */
3904 buffer[3*i+0] = (png_byte)((v >> 8) & 0xff);
3905 buffer[3*i+1] = (png_byte)(v & 0xff);
3906 buffer[3*i+2] = (png_byte)(((v >> 8) ^ v) & 0xff);
3907 ++v;
3908 ++i;
3909 }
3910
3911 return;
3912
3913 case 32:
3914 /* 65535 pixels, r, g, b, a; just replicate */
3915 while (i<128)
3916 {
3917 buffer[4*i+0] = (png_byte)((v >> 8) & 0xff);
3918 buffer[4*i+1] = (png_byte)(v & 0xff);
3919 buffer[4*i+2] = (png_byte)((v >> 8) & 0xff);
3920 buffer[4*i+3] = (png_byte)(v & 0xff);
3921 ++v;
3922 ++i;
3923 }
3924
3925 return;
3926
3927 case 48:
3928 /* y is maximum 2047, giving 4x65536 pixels, make 'r' increase by 1 at
3929 * each pixel, g increase by 257 (0x101) and 'b' by 0x1111:
3930 */
3931 while (i<128)
3932 {
3933 png_uint_32 t = v++;
3934 buffer[6*i+0] = (png_byte)((t >> 8) & 0xff);
3935 buffer[6*i+1] = (png_byte)(t & 0xff);
3936 t *= 257;
3937 buffer[6*i+2] = (png_byte)((t >> 8) & 0xff);
3938 buffer[6*i+3] = (png_byte)(t & 0xff);
3939 t *= 17;
3940 buffer[6*i+4] = (png_byte)((t >> 8) & 0xff);
3941 buffer[6*i+5] = (png_byte)(t & 0xff);
3942 ++i;
3943 }
3944
3945 return;
3946
3947 case 64:
3948 /* As above in the 32 bit case. */
3949 while (i<128)
3950 {
3951 png_uint_32 t = v++;
3952 buffer[8*i+0] = (png_byte)((t >> 8) & 0xff);
3953 buffer[8*i+1] = (png_byte)(t & 0xff);
3954 buffer[8*i+4] = (png_byte)((t >> 8) & 0xff);
3955 buffer[8*i+5] = (png_byte)(t & 0xff);
3956 t *= 257;
3957 buffer[8*i+2] = (png_byte)((t >> 8) & 0xff);
3958 buffer[8*i+3] = (png_byte)(t & 0xff);
3959 buffer[8*i+6] = (png_byte)((t >> 8) & 0xff);
3960 buffer[8*i+7] = (png_byte)(t & 0xff);
3961 ++i;
3962 }
3963 return;
3964
3965 default:
3966 break;
3967 }
3968
3969 png_error(pp, "internal error");
3970 }
3971
3972 /* This is just to do the right cast - could be changed to a function to check
3973 * 'bd' but there isn't much point.
3974 */
3975 #define DEPTH(bd) ((png_byte)(1U << (bd)))
3976
3977 /* This is just a helper for compiling on minimal systems with no write
3978 * interlacing support. If there is no write interlacing we can't generate test
3979 * cases with interlace:
3980 */
3981 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
3982 # define INTERLACE_LAST PNG_INTERLACE_LAST
3983 # define check_interlace_type(type) ((void)(type))
3984 # define set_write_interlace_handling(pp,type) png_set_interlace_handling(pp)
3985 # define do_own_interlace 0
3986 #elif PNG_LIBPNG_VER < 10700
3987 # define set_write_interlace_handling(pp,type) (1)
3988 static void
check_interlace_type(int const interlace_type)3989 check_interlace_type(int const interlace_type)
3990 {
3991 /* Prior to 1.7.0 libpng does not support the write of an interlaced image
3992 * unless PNG_WRITE_INTERLACING_SUPPORTED, even with do_interlace so the
3993 * code here does the pixel interlace itself, so:
3994 */
3995 if (interlace_type != PNG_INTERLACE_NONE)
3996 {
3997 /* This is an internal error - --interlace tests should be skipped, not
3998 * attempted.
3999 */
4000 fprintf(stderr, "pngvalid: no interlace support\n");
4001 exit(99);
4002 }
4003 }
4004 # define INTERLACE_LAST (PNG_INTERLACE_NONE+1)
4005 # define do_own_interlace 0
4006 #else /* libpng 1.7+ */
4007 # define set_write_interlace_handling(pp,type)\
4008 npasses_from_interlace_type(pp,type)
4009 # define check_interlace_type(type) ((void)(type))
4010 # define INTERLACE_LAST PNG_INTERLACE_LAST
4011 # define do_own_interlace 1
4012 #endif /* WRITE_INTERLACING tests */
4013
4014 #define CAN_WRITE_INTERLACE\
4015 PNG_LIBPNG_VER >= 10700 || defined PNG_WRITE_INTERLACING_SUPPORTED
4016
4017 /* Do the same thing for read interlacing; this controls whether read tests do
4018 * their own de-interlace or use libpng.
4019 */
4020 #ifdef PNG_READ_INTERLACING_SUPPORTED
4021 # define do_read_interlace 0
4022 #else /* no libpng read interlace support */
4023 # define do_read_interlace 1
4024 #endif
4025 /* The following two routines use the PNG interlace support macros from
4026 * png.h to interlace or deinterlace rows.
4027 */
4028 static void
interlace_row(png_bytep buffer,png_const_bytep imageRow,unsigned int pixel_size,png_uint_32 w,int pass,int littleendian)4029 interlace_row(png_bytep buffer, png_const_bytep imageRow,
4030 unsigned int pixel_size, png_uint_32 w, int pass, int littleendian)
4031 {
4032 png_uint_32 xin, xout, xstep;
4033
4034 /* Note that this can, trivially, be optimized to a memcpy on pass 7, the
4035 * code is presented this way to make it easier to understand. In practice
4036 * consult the code in the libpng source to see other ways of doing this.
4037 *
4038 * It is OK for buffer and imageRow to be identical, because 'xin' moves
4039 * faster than 'xout' and we copy up.
4040 */
4041 xin = PNG_PASS_START_COL(pass);
4042 xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
4043
4044 for (xout=0; xin<w; xin+=xstep)
4045 {
4046 pixel_copy(buffer, xout, imageRow, xin, pixel_size, littleendian);
4047 ++xout;
4048 }
4049 }
4050
4051 #ifdef PNG_READ_SUPPORTED
4052 static void
deinterlace_row(png_bytep buffer,png_const_bytep row,unsigned int pixel_size,png_uint_32 w,int pass,int littleendian)4053 deinterlace_row(png_bytep buffer, png_const_bytep row,
4054 unsigned int pixel_size, png_uint_32 w, int pass, int littleendian)
4055 {
4056 /* The inverse of the above, 'row' is part of row 'y' of the output image,
4057 * in 'buffer'. The image is 'w' wide and this is pass 'pass', distribute
4058 * the pixels of row into buffer and return the number written (to allow
4059 * this to be checked).
4060 */
4061 png_uint_32 xin, xout, xstep;
4062
4063 xout = PNG_PASS_START_COL(pass);
4064 xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
4065
4066 for (xin=0; xout<w; xout+=xstep)
4067 {
4068 pixel_copy(buffer, xout, row, xin, pixel_size, littleendian);
4069 ++xin;
4070 }
4071 }
4072 #endif /* PNG_READ_SUPPORTED */
4073
4074 /* Make a standardized image given an image colour type, bit depth and
4075 * interlace type. The standard images have a very restricted range of
4076 * rows and heights and are used for testing transforms rather than image
4077 * layout details. See make_size_images below for a way to make images
4078 * that test odd sizes along with the libpng interlace handling.
4079 */
4080 #ifdef PNG_WRITE_FILTER_SUPPORTED
4081 static void
choose_random_filter(png_structp pp,int start)4082 choose_random_filter(png_structp pp, int start)
4083 {
4084 /* Choose filters randomly except that on the very first row ensure that
4085 * there is at least one previous row filter.
4086 */
4087 int filters = PNG_ALL_FILTERS & random_mod(256U);
4088
4089 /* There may be no filters; skip the setting. */
4090 if (filters != 0)
4091 {
4092 if (start && filters < PNG_FILTER_UP)
4093 filters |= PNG_FILTER_UP;
4094
4095 png_set_filter(pp, 0/*method*/, filters);
4096 }
4097 }
4098 #else /* !WRITE_FILTER */
4099 # define choose_random_filter(pp, start) ((void)0)
4100 #endif /* !WRITE_FILTER */
4101
4102 static void
make_transform_image(png_store * const ps,png_byte const colour_type,png_byte const bit_depth,unsigned int palette_number,int interlace_type,png_const_charp name)4103 make_transform_image(png_store* const ps, png_byte const colour_type,
4104 png_byte const bit_depth, unsigned int palette_number,
4105 int interlace_type, png_const_charp name)
4106 {
4107 context(ps, fault);
4108
4109 check_interlace_type(interlace_type);
4110
4111 Try
4112 {
4113 png_infop pi;
4114 png_structp pp = set_store_for_write(ps, &pi, name);
4115 png_uint_32 h, w;
4116
4117 /* In the event of a problem return control to the Catch statement below
4118 * to do the clean up - it is not possible to 'return' directly from a Try
4119 * block.
4120 */
4121 if (pp == NULL)
4122 Throw ps;
4123
4124 w = transform_width(pp, colour_type, bit_depth);
4125 h = transform_height(pp, colour_type, bit_depth);
4126
4127 png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
4128 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
4129
4130 #ifdef PNG_TEXT_SUPPORTED
4131 # if defined(PNG_READ_zTXt_SUPPORTED) && defined(PNG_WRITE_zTXt_SUPPORTED)
4132 # define TEXT_COMPRESSION PNG_TEXT_COMPRESSION_zTXt
4133 # else
4134 # define TEXT_COMPRESSION PNG_TEXT_COMPRESSION_NONE
4135 # endif
4136 {
4137 static char key[] = "image name"; /* must be writeable */
4138 size_t pos;
4139 png_text text;
4140 char copy[FILE_NAME_SIZE];
4141
4142 /* Use a compressed text string to test the correct interaction of text
4143 * compression and IDAT compression.
4144 */
4145 text.compression = TEXT_COMPRESSION;
4146 text.key = key;
4147 /* Yuck: the text must be writable! */
4148 pos = safecat(copy, sizeof copy, 0, ps->wname);
4149 text.text = copy;
4150 text.text_length = pos;
4151 text.itxt_length = 0;
4152 text.lang = 0;
4153 text.lang_key = 0;
4154
4155 png_set_text(pp, pi, &text, 1);
4156 }
4157 #endif
4158
4159 if (colour_type == 3) /* palette */
4160 init_standard_palette(ps, pp, pi, 1U << bit_depth, 1/*do tRNS*/);
4161
4162 # ifdef PNG_WRITE_tRNS_SUPPORTED
4163 else if (palette_number)
4164 set_random_tRNS(pp, pi, colour_type, bit_depth);
4165 # endif
4166
4167 png_write_info(pp, pi);
4168
4169 if (png_get_rowbytes(pp, pi) !=
4170 transform_rowsize(pp, colour_type, bit_depth))
4171 png_error(pp, "transform row size incorrect");
4172
4173 else
4174 {
4175 /* Somewhat confusingly this must be called *after* png_write_info
4176 * because if it is called before, the information in *pp has not been
4177 * updated to reflect the interlaced image.
4178 */
4179 int npasses = set_write_interlace_handling(pp, interlace_type);
4180 int pass;
4181
4182 if (npasses != npasses_from_interlace_type(pp, interlace_type))
4183 png_error(pp, "write: png_set_interlace_handling failed");
4184
4185 for (pass=0; pass<npasses; ++pass)
4186 {
4187 png_uint_32 y;
4188
4189 /* do_own_interlace is a pre-defined boolean (a #define) which is
4190 * set if we have to work out the interlaced rows here.
4191 */
4192 for (y=0; y<h; ++y)
4193 {
4194 png_byte buffer[TRANSFORM_ROWMAX];
4195
4196 transform_row(pp, buffer, colour_type, bit_depth, y);
4197
4198 # if do_own_interlace
4199 /* If do_own_interlace *and* the image is interlaced we need a
4200 * reduced interlace row; this may be reduced to empty.
4201 */
4202 if (interlace_type == PNG_INTERLACE_ADAM7)
4203 {
4204 /* The row must not be written if it doesn't exist, notice
4205 * that there are two conditions here, either the row isn't
4206 * ever in the pass or the row would be but isn't wide
4207 * enough to contribute any pixels. In fact the wPass test
4208 * can be used to skip the whole y loop in this case.
4209 */
4210 if (PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
4211 PNG_PASS_COLS(w, pass) > 0)
4212 interlace_row(buffer, buffer,
4213 bit_size(pp, colour_type, bit_depth), w, pass,
4214 0/*data always bigendian*/);
4215 else
4216 continue;
4217 }
4218 # endif /* do_own_interlace */
4219
4220 choose_random_filter(pp, pass == 0 && y == 0);
4221 png_write_row(pp, buffer);
4222 }
4223 }
4224 }
4225
4226 #ifdef PNG_TEXT_SUPPORTED
4227 {
4228 static char key[] = "end marker";
4229 static char comment[] = "end";
4230 png_text text;
4231
4232 /* Use a compressed text string to test the correct interaction of text
4233 * compression and IDAT compression.
4234 */
4235 text.compression = TEXT_COMPRESSION;
4236 text.key = key;
4237 text.text = comment;
4238 text.text_length = (sizeof comment)-1;
4239 text.itxt_length = 0;
4240 text.lang = 0;
4241 text.lang_key = 0;
4242
4243 png_set_text(pp, pi, &text, 1);
4244 }
4245 #endif
4246
4247 png_write_end(pp, pi);
4248
4249 /* And store this under the appropriate id, then clean up. */
4250 store_storefile(ps, FILEID(colour_type, bit_depth, palette_number,
4251 interlace_type, 0, 0, 0));
4252
4253 store_write_reset(ps);
4254 }
4255
4256 Catch(fault)
4257 {
4258 /* Use the png_store returned by the exception. This may help the compiler
4259 * because 'ps' is not used in this branch of the setjmp. Note that fault
4260 * and ps will always be the same value.
4261 */
4262 store_write_reset(fault);
4263 }
4264 }
4265
4266 static void
make_transform_images(png_modifier * pm)4267 make_transform_images(png_modifier *pm)
4268 {
4269 png_byte colour_type = 0;
4270 png_byte bit_depth = 0;
4271 unsigned int palette_number = 0;
4272
4273 /* This is in case of errors. */
4274 safecat(pm->this.test, sizeof pm->this.test, 0, "make standard images");
4275
4276 /* Use next_format to enumerate all the combinations we test, including
4277 * generating multiple low bit depth palette images. Non-A images (palette
4278 * and direct) are created with and without tRNS chunks.
4279 */
4280 while (next_format(&colour_type, &bit_depth, &palette_number, 1, 1))
4281 {
4282 int interlace_type;
4283
4284 for (interlace_type = PNG_INTERLACE_NONE;
4285 interlace_type < INTERLACE_LAST; ++interlace_type)
4286 {
4287 char name[FILE_NAME_SIZE];
4288
4289 standard_name(name, sizeof name, 0, colour_type, bit_depth,
4290 palette_number, interlace_type, 0, 0, do_own_interlace);
4291 make_transform_image(&pm->this, colour_type, bit_depth, palette_number,
4292 interlace_type, name);
4293 }
4294 }
4295 }
4296
4297 /* Build a single row for the 'size' test images; this fills in only the
4298 * first bit_width bits of the sample row.
4299 */
4300 static void
size_row(png_byte buffer[SIZE_ROWMAX],png_uint_32 bit_width,png_uint_32 y)4301 size_row(png_byte buffer[SIZE_ROWMAX], png_uint_32 bit_width, png_uint_32 y)
4302 {
4303 /* height is in the range 1 to 16, so: */
4304 y = ((y & 1) << 7) + ((y & 2) << 6) + ((y & 4) << 5) + ((y & 8) << 4);
4305 /* the following ensures bits are set in small images: */
4306 y ^= 0xA5;
4307
4308 while (bit_width >= 8)
4309 *buffer++ = (png_byte)y++, bit_width -= 8;
4310
4311 /* There may be up to 7 remaining bits, these go in the most significant
4312 * bits of the byte.
4313 */
4314 if (bit_width > 0)
4315 {
4316 png_uint_32 mask = (1U<<(8-bit_width))-1;
4317 *buffer = (png_byte)((*buffer & mask) | (y & ~mask));
4318 }
4319 }
4320
4321 static void
make_size_image(png_store * const ps,png_byte const colour_type,png_byte const bit_depth,int const interlace_type,png_uint_32 const w,png_uint_32 const h,int const do_interlace)4322 make_size_image(png_store* const ps, png_byte const colour_type,
4323 png_byte const bit_depth, int const interlace_type,
4324 png_uint_32 const w, png_uint_32 const h,
4325 int const do_interlace)
4326 {
4327 context(ps, fault);
4328
4329 check_interlace_type(interlace_type);
4330
4331 Try
4332 {
4333 png_infop pi;
4334 png_structp pp;
4335 unsigned int pixel_size;
4336
4337 /* Make a name and get an appropriate id for the store: */
4338 char name[FILE_NAME_SIZE];
4339 const png_uint_32 id = FILEID(colour_type, bit_depth, 0/*palette*/,
4340 interlace_type, w, h, do_interlace);
4341
4342 standard_name_from_id(name, sizeof name, 0, id);
4343 pp = set_store_for_write(ps, &pi, name);
4344
4345 /* In the event of a problem return control to the Catch statement below
4346 * to do the clean up - it is not possible to 'return' directly from a Try
4347 * block.
4348 */
4349 if (pp == NULL)
4350 Throw ps;
4351
4352 png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
4353 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
4354
4355 #ifdef PNG_TEXT_SUPPORTED
4356 {
4357 static char key[] = "image name"; /* must be writeable */
4358 size_t pos;
4359 png_text text;
4360 char copy[FILE_NAME_SIZE];
4361
4362 /* Use a compressed text string to test the correct interaction of text
4363 * compression and IDAT compression.
4364 */
4365 text.compression = TEXT_COMPRESSION;
4366 text.key = key;
4367 /* Yuck: the text must be writable! */
4368 pos = safecat(copy, sizeof copy, 0, ps->wname);
4369 text.text = copy;
4370 text.text_length = pos;
4371 text.itxt_length = 0;
4372 text.lang = 0;
4373 text.lang_key = 0;
4374
4375 png_set_text(pp, pi, &text, 1);
4376 }
4377 #endif
4378
4379 if (colour_type == 3) /* palette */
4380 init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
4381
4382 png_write_info(pp, pi);
4383
4384 /* Calculate the bit size, divide by 8 to get the byte size - this won't
4385 * overflow because we know the w values are all small enough even for
4386 * a system where 'unsigned int' is only 16 bits.
4387 */
4388 pixel_size = bit_size(pp, colour_type, bit_depth);
4389 if (png_get_rowbytes(pp, pi) != ((w * pixel_size) + 7) / 8)
4390 png_error(pp, "size row size incorrect");
4391
4392 else
4393 {
4394 int npasses = npasses_from_interlace_type(pp, interlace_type);
4395 png_uint_32 y;
4396 int pass;
4397 png_byte image[16][SIZE_ROWMAX];
4398
4399 /* To help consistent error detection make the parts of this buffer
4400 * that aren't set below all '1':
4401 */
4402 memset(image, 0xff, sizeof image);
4403
4404 if (!do_interlace &&
4405 npasses != set_write_interlace_handling(pp, interlace_type))
4406 png_error(pp, "write: png_set_interlace_handling failed");
4407
4408 /* Prepare the whole image first to avoid making it 7 times: */
4409 for (y=0; y<h; ++y)
4410 size_row(image[y], w * pixel_size, y);
4411
4412 for (pass=0; pass<npasses; ++pass)
4413 {
4414 /* The following two are for checking the macros: */
4415 const png_uint_32 wPass = PNG_PASS_COLS(w, pass);
4416
4417 /* If do_interlace is set we don't call png_write_row for every
4418 * row because some of them are empty. In fact, for a 1x1 image,
4419 * most of them are empty!
4420 */
4421 for (y=0; y<h; ++y)
4422 {
4423 png_const_bytep row = image[y];
4424 png_byte tempRow[SIZE_ROWMAX];
4425
4426 /* If do_interlace *and* the image is interlaced we
4427 * need a reduced interlace row; this may be reduced
4428 * to empty.
4429 */
4430 if (do_interlace && interlace_type == PNG_INTERLACE_ADAM7)
4431 {
4432 /* The row must not be written if it doesn't exist, notice
4433 * that there are two conditions here, either the row isn't
4434 * ever in the pass or the row would be but isn't wide
4435 * enough to contribute any pixels. In fact the wPass test
4436 * can be used to skip the whole y loop in this case.
4437 */
4438 if (PNG_ROW_IN_INTERLACE_PASS(y, pass) && wPass > 0)
4439 {
4440 /* Set to all 1's for error detection (libpng tends to
4441 * set unset things to 0).
4442 */
4443 memset(tempRow, 0xff, sizeof tempRow);
4444 interlace_row(tempRow, row, pixel_size, w, pass,
4445 0/*data always bigendian*/);
4446 row = tempRow;
4447 }
4448 else
4449 continue;
4450 }
4451
4452 # ifdef PNG_WRITE_FILTER_SUPPORTED
4453 /* Only get to here if the row has some pixels in it, set the
4454 * filters to 'all' for the very first row and thereafter to a
4455 * single filter. It isn't well documented, but png_set_filter
4456 * does accept a filter number (per the spec) as well as a bit
4457 * mask.
4458 *
4459 * The code now uses filters at random, except that on the first
4460 * row of an image it ensures that a previous row filter is in
4461 * the set so that libpng allocates the row buffer.
4462 */
4463 {
4464 int filters = 8 << random_mod(PNG_FILTER_VALUE_LAST);
4465
4466 if (pass == 0 && y == 0 &&
4467 (filters < PNG_FILTER_UP || w == 1U))
4468 filters |= PNG_FILTER_UP;
4469
4470 png_set_filter(pp, 0/*method*/, filters);
4471 }
4472 # endif
4473
4474 png_write_row(pp, row);
4475 }
4476 }
4477 }
4478
4479 #ifdef PNG_TEXT_SUPPORTED
4480 {
4481 static char key[] = "end marker";
4482 static char comment[] = "end";
4483 png_text text;
4484
4485 /* Use a compressed text string to test the correct interaction of text
4486 * compression and IDAT compression.
4487 */
4488 text.compression = TEXT_COMPRESSION;
4489 text.key = key;
4490 text.text = comment;
4491 text.text_length = (sizeof comment)-1;
4492 text.itxt_length = 0;
4493 text.lang = 0;
4494 text.lang_key = 0;
4495
4496 png_set_text(pp, pi, &text, 1);
4497 }
4498 #endif
4499
4500 png_write_end(pp, pi);
4501
4502 /* And store this under the appropriate id, then clean up. */
4503 store_storefile(ps, id);
4504
4505 store_write_reset(ps);
4506 }
4507
4508 Catch(fault)
4509 {
4510 /* Use the png_store returned by the exception. This may help the compiler
4511 * because 'ps' is not used in this branch of the setjmp. Note that fault
4512 * and ps will always be the same value.
4513 */
4514 store_write_reset(fault);
4515 }
4516 }
4517
4518 static void
make_size(png_store * const ps,png_byte const colour_type,int bdlo,int const bdhi)4519 make_size(png_store* const ps, png_byte const colour_type, int bdlo,
4520 int const bdhi)
4521 {
4522 for (; bdlo <= bdhi; ++bdlo)
4523 {
4524 png_uint_32 width;
4525
4526 for (width = 1; width <= 16; ++width)
4527 {
4528 png_uint_32 height;
4529
4530 for (height = 1; height <= 16; ++height)
4531 {
4532 /* The four combinations of DIY interlace and interlace or not -
4533 * no interlace + DIY should be identical to no interlace with
4534 * libpng doing it.
4535 */
4536 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
4537 width, height, 0);
4538 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
4539 width, height, 1);
4540 # ifdef PNG_WRITE_INTERLACING_SUPPORTED
4541 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
4542 width, height, 0);
4543 # endif
4544 # if CAN_WRITE_INTERLACE
4545 /* 1.7.0 removes the hack that prevented app write of an interlaced
4546 * image if WRITE_INTERLACE was not supported
4547 */
4548 make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
4549 width, height, 1);
4550 # endif
4551 }
4552 }
4553 }
4554 }
4555
4556 static void
make_size_images(png_store * ps)4557 make_size_images(png_store *ps)
4558 {
4559 /* This is in case of errors. */
4560 safecat(ps->test, sizeof ps->test, 0, "make size images");
4561
4562 /* Arguments are colour_type, low bit depth, high bit depth
4563 */
4564 make_size(ps, 0, 0, WRITE_BDHI);
4565 make_size(ps, 2, 3, WRITE_BDHI);
4566 make_size(ps, 3, 0, 3 /*palette: max 8 bits*/);
4567 make_size(ps, 4, 3, WRITE_BDHI);
4568 make_size(ps, 6, 3, WRITE_BDHI);
4569 }
4570
4571 #ifdef PNG_READ_SUPPORTED
4572 /* Return a row based on image id and 'y' for checking: */
4573 static void
standard_row(png_const_structp pp,png_byte std[STANDARD_ROWMAX],png_uint_32 id,png_uint_32 y)4574 standard_row(png_const_structp pp, png_byte std[STANDARD_ROWMAX],
4575 png_uint_32 id, png_uint_32 y)
4576 {
4577 if (WIDTH_FROM_ID(id) == 0)
4578 transform_row(pp, std, COL_FROM_ID(id), DEPTH_FROM_ID(id), y);
4579 else
4580 size_row(std, WIDTH_FROM_ID(id) * bit_size(pp, COL_FROM_ID(id),
4581 DEPTH_FROM_ID(id)), y);
4582 }
4583 #endif /* PNG_READ_SUPPORTED */
4584
4585 /* Tests - individual test cases */
4586 /* Like 'make_standard' but errors are deliberately introduced into the calls
4587 * to ensure that they get detected - it should not be possible to write an
4588 * invalid image with libpng!
4589 */
4590 /* TODO: the 'set' functions can probably all be made to take a
4591 * png_const_structp rather than a modifiable one.
4592 */
4593 #ifdef PNG_WARNINGS_SUPPORTED
4594 static void
sBIT0_error_fn(png_structp pp,png_infop pi)4595 sBIT0_error_fn(png_structp pp, png_infop pi)
4596 {
4597 /* 0 is invalid... */
4598 png_color_8 bad;
4599 bad.red = bad.green = bad.blue = bad.gray = bad.alpha = 0;
4600 png_set_sBIT(pp, pi, &bad);
4601 }
4602
4603 static void
sBIT_error_fn(png_structp pp,png_infop pi)4604 sBIT_error_fn(png_structp pp, png_infop pi)
4605 {
4606 png_byte bit_depth;
4607 png_color_8 bad;
4608
4609 if (png_get_color_type(pp, pi) == PNG_COLOR_TYPE_PALETTE)
4610 bit_depth = 8;
4611
4612 else
4613 bit_depth = png_get_bit_depth(pp, pi);
4614
4615 /* Now we know the bit depth we can easily generate an invalid sBIT entry */
4616 bad.red = bad.green = bad.blue = bad.gray = bad.alpha =
4617 (png_byte)(bit_depth+1);
4618 png_set_sBIT(pp, pi, &bad);
4619 }
4620
4621 static const struct
4622 {
4623 void (*fn)(png_structp, png_infop);
4624 const char *msg;
4625 unsigned int warning :1; /* the error is a warning... */
4626 } error_test[] =
4627 {
4628 /* no warnings makes these errors undetectable prior to 1.7.0 */
4629 { sBIT0_error_fn, "sBIT(0): failed to detect error",
4630 PNG_LIBPNG_VER < 10700 },
4631
4632 { sBIT_error_fn, "sBIT(too big): failed to detect error",
4633 PNG_LIBPNG_VER < 10700 },
4634 };
4635
4636 static void
make_error(png_store * const ps,png_byte const colour_type,png_byte bit_depth,int interlace_type,int test,png_const_charp name)4637 make_error(png_store* const ps, png_byte const colour_type,
4638 png_byte bit_depth, int interlace_type, int test, png_const_charp name)
4639 {
4640 context(ps, fault);
4641
4642 check_interlace_type(interlace_type);
4643
4644 Try
4645 {
4646 png_infop pi;
4647 const png_structp pp = set_store_for_write(ps, &pi, name);
4648 png_uint_32 w, h;
4649 gnu_volatile(pp)
4650
4651 if (pp == NULL)
4652 Throw ps;
4653
4654 w = transform_width(pp, colour_type, bit_depth);
4655 gnu_volatile(w)
4656 h = transform_height(pp, colour_type, bit_depth);
4657 gnu_volatile(h)
4658 png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
4659 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
4660
4661 if (colour_type == 3) /* palette */
4662 init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
4663
4664 /* Time for a few errors; these are in various optional chunks, the
4665 * standard tests test the standard chunks pretty well.
4666 */
4667 # define exception__prev exception_prev_1
4668 # define exception__env exception_env_1
4669 Try
4670 {
4671 gnu_volatile(exception__prev)
4672
4673 /* Expect this to throw: */
4674 ps->expect_error = !error_test[test].warning;
4675 ps->expect_warning = error_test[test].warning;
4676 ps->saw_warning = 0;
4677 error_test[test].fn(pp, pi);
4678
4679 /* Normally the error is only detected here: */
4680 png_write_info(pp, pi);
4681
4682 /* And handle the case where it was only a warning: */
4683 if (ps->expect_warning && ps->saw_warning)
4684 Throw ps;
4685
4686 /* If we get here there is a problem, we have success - no error or
4687 * no warning - when we shouldn't have success. Log an error.
4688 */
4689 store_log(ps, pp, error_test[test].msg, 1 /*error*/);
4690 }
4691
4692 Catch (fault)
4693 { /* expected exit */
4694 }
4695 #undef exception__prev
4696 #undef exception__env
4697
4698 /* And clear these flags */
4699 ps->expect_warning = 0;
4700
4701 if (ps->expect_error)
4702 ps->expect_error = 0;
4703
4704 else
4705 {
4706 /* Now write the whole image, just to make sure that the detected, or
4707 * undetected, errro has not created problems inside libpng. This
4708 * doesn't work if there was a png_error in png_write_info because that
4709 * can abort before PLTE was written.
4710 */
4711 if (png_get_rowbytes(pp, pi) !=
4712 transform_rowsize(pp, colour_type, bit_depth))
4713 png_error(pp, "row size incorrect");
4714
4715 else
4716 {
4717 int npasses = set_write_interlace_handling(pp, interlace_type);
4718 int pass;
4719
4720 if (npasses != npasses_from_interlace_type(pp, interlace_type))
4721 png_error(pp, "write: png_set_interlace_handling failed");
4722
4723 for (pass=0; pass<npasses; ++pass)
4724 {
4725 png_uint_32 y;
4726
4727 for (y=0; y<h; ++y)
4728 {
4729 png_byte buffer[TRANSFORM_ROWMAX];
4730
4731 transform_row(pp, buffer, colour_type, bit_depth, y);
4732
4733 # if do_own_interlace
4734 /* If do_own_interlace *and* the image is interlaced we
4735 * need a reduced interlace row; this may be reduced to
4736 * empty.
4737 */
4738 if (interlace_type == PNG_INTERLACE_ADAM7)
4739 {
4740 /* The row must not be written if it doesn't exist,
4741 * notice that there are two conditions here, either the
4742 * row isn't ever in the pass or the row would be but
4743 * isn't wide enough to contribute any pixels. In fact
4744 * the wPass test can be used to skip the whole y loop
4745 * in this case.
4746 */
4747 if (PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
4748 PNG_PASS_COLS(w, pass) > 0)
4749 interlace_row(buffer, buffer,
4750 bit_size(pp, colour_type, bit_depth), w, pass,
4751 0/*data always bigendian*/);
4752 else
4753 continue;
4754 }
4755 # endif /* do_own_interlace */
4756
4757 png_write_row(pp, buffer);
4758 }
4759 }
4760 } /* image writing */
4761
4762 png_write_end(pp, pi);
4763 }
4764
4765 /* The following deletes the file that was just written. */
4766 store_write_reset(ps);
4767 }
4768
4769 Catch(fault)
4770 {
4771 store_write_reset(fault);
4772 }
4773 }
4774
4775 static int
make_errors(png_modifier * const pm,png_byte const colour_type,int bdlo,int const bdhi)4776 make_errors(png_modifier* const pm, png_byte const colour_type,
4777 int bdlo, int const bdhi)
4778 {
4779 for (; bdlo <= bdhi; ++bdlo)
4780 {
4781 int interlace_type;
4782
4783 for (interlace_type = PNG_INTERLACE_NONE;
4784 interlace_type < INTERLACE_LAST; ++interlace_type)
4785 {
4786 unsigned int test;
4787 char name[FILE_NAME_SIZE];
4788
4789 standard_name(name, sizeof name, 0, colour_type, 1<<bdlo, 0,
4790 interlace_type, 0, 0, do_own_interlace);
4791
4792 for (test=0; test<ARRAY_SIZE(error_test); ++test)
4793 {
4794 make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type,
4795 test, name);
4796
4797 if (fail(pm))
4798 return 0;
4799 }
4800 }
4801 }
4802
4803 return 1; /* keep going */
4804 }
4805 #endif /* PNG_WARNINGS_SUPPORTED */
4806
4807 static void
perform_error_test(png_modifier * pm)4808 perform_error_test(png_modifier *pm)
4809 {
4810 #ifdef PNG_WARNINGS_SUPPORTED /* else there are no cases that work! */
4811 /* Need to do this here because we just write in this test. */
4812 safecat(pm->this.test, sizeof pm->this.test, 0, "error test");
4813
4814 if (!make_errors(pm, 0, 0, WRITE_BDHI))
4815 return;
4816
4817 if (!make_errors(pm, 2, 3, WRITE_BDHI))
4818 return;
4819
4820 if (!make_errors(pm, 3, 0, 3))
4821 return;
4822
4823 if (!make_errors(pm, 4, 3, WRITE_BDHI))
4824 return;
4825
4826 if (!make_errors(pm, 6, 3, WRITE_BDHI))
4827 return;
4828 #else
4829 UNUSED(pm)
4830 #endif
4831 }
4832
4833 /* This is just to validate the internal PNG formatting code - if this fails
4834 * then the warning messages the library outputs will probably be garbage.
4835 */
4836 static void
perform_formatting_test(png_store * ps)4837 perform_formatting_test(png_store *ps)
4838 {
4839 #ifdef PNG_TIME_RFC1123_SUPPORTED
4840 /* The handle into the formatting code is the RFC1123 support; this test does
4841 * nothing if that is compiled out.
4842 */
4843 context(ps, fault);
4844
4845 Try
4846 {
4847 png_const_charp correct = "29 Aug 2079 13:53:60 +0000";
4848 png_const_charp result;
4849 # if PNG_LIBPNG_VER >= 10600
4850 char timestring[29];
4851 # endif
4852 png_structp pp;
4853 png_time pt;
4854
4855 pp = set_store_for_write(ps, NULL, "libpng formatting test");
4856
4857 if (pp == NULL)
4858 Throw ps;
4859
4860
4861 /* Arbitrary settings: */
4862 pt.year = 2079;
4863 pt.month = 8;
4864 pt.day = 29;
4865 pt.hour = 13;
4866 pt.minute = 53;
4867 pt.second = 60; /* a leap second */
4868
4869 # if PNG_LIBPNG_VER < 10600
4870 result = png_convert_to_rfc1123(pp, &pt);
4871 # else
4872 if (png_convert_to_rfc1123_buffer(timestring, &pt))
4873 result = timestring;
4874
4875 else
4876 result = NULL;
4877 # endif
4878
4879 if (result == NULL)
4880 png_error(pp, "png_convert_to_rfc1123 failed");
4881
4882 if (strcmp(result, correct) != 0)
4883 {
4884 size_t pos = 0;
4885 char msg[128];
4886
4887 pos = safecat(msg, sizeof msg, pos, "png_convert_to_rfc1123(");
4888 pos = safecat(msg, sizeof msg, pos, correct);
4889 pos = safecat(msg, sizeof msg, pos, ") returned: '");
4890 pos = safecat(msg, sizeof msg, pos, result);
4891 pos = safecat(msg, sizeof msg, pos, "'");
4892
4893 png_error(pp, msg);
4894 }
4895
4896 store_write_reset(ps);
4897 }
4898
4899 Catch(fault)
4900 {
4901 store_write_reset(fault);
4902 }
4903 #else
4904 UNUSED(ps)
4905 #endif
4906 }
4907
4908 #ifdef PNG_READ_SUPPORTED
4909 /* Because we want to use the same code in both the progressive reader and the
4910 * sequential reader it is necessary to deal with the fact that the progressive
4911 * reader callbacks only have one parameter (png_get_progressive_ptr()), so this
4912 * must contain all the test parameters and all the local variables directly
4913 * accessible to the sequential reader implementation.
4914 *
4915 * The technique adopted is to reinvent part of what Dijkstra termed a
4916 * 'display'; an array of pointers to the stack frames of enclosing functions so
4917 * that a nested function definition can access the local (C auto) variables of
4918 * the functions that contain its definition. In fact C provides the first
4919 * pointer (the local variables - the stack frame pointer) and the last (the
4920 * global variables - the BCPL global vector typically implemented as global
4921 * addresses), this code requires one more pointer to make the display - the
4922 * local variables (and function call parameters) of the function that actually
4923 * invokes either the progressive or sequential reader.
4924 *
4925 * Perhaps confusingly this technique is confounded with classes - the
4926 * 'standard_display' defined here is sub-classed as the 'gamma_display' below.
4927 * A gamma_display is a standard_display, taking advantage of the ANSI-C
4928 * requirement that the pointer to the first member of a structure must be the
4929 * same as the pointer to the structure. This allows us to reuse standard_
4930 * functions in the gamma test code; something that could not be done with
4931 * nested functions!
4932 */
4933 typedef struct standard_display
4934 {
4935 png_store* ps; /* Test parameters (passed to the function) */
4936 png_byte colour_type;
4937 png_byte bit_depth;
4938 png_byte red_sBIT; /* Input data sBIT values. */
4939 png_byte green_sBIT;
4940 png_byte blue_sBIT;
4941 png_byte alpha_sBIT;
4942 png_byte interlace_type;
4943 png_byte filler; /* Output has a filler */
4944 png_uint_32 id; /* Calculated file ID */
4945 png_uint_32 w; /* Width of image */
4946 png_uint_32 h; /* Height of image */
4947 int npasses; /* Number of interlaced passes */
4948 png_uint_32 pixel_size; /* Width of one pixel in bits */
4949 png_uint_32 bit_width; /* Width of output row in bits */
4950 size_t cbRow; /* Bytes in a row of the output image */
4951 int do_interlace; /* Do interlacing internally */
4952 int littleendian; /* App (row) data is little endian */
4953 int is_transparent; /* Transparency information was present. */
4954 int has_tRNS; /* color type GRAY or RGB with a tRNS chunk. */
4955 int speed; /* Doing a speed test */
4956 int use_update_info;/* Call update_info, not start_image */
4957 struct
4958 {
4959 png_uint_16 red;
4960 png_uint_16 green;
4961 png_uint_16 blue;
4962 } transparent; /* The transparent color, if set. */
4963 int npalette; /* Number of entries in the palette. */
4964 store_palette
4965 palette;
4966 } standard_display;
4967
4968 static void
standard_display_init(standard_display * dp,png_store * ps,png_uint_32 id,int do_interlace,int use_update_info)4969 standard_display_init(standard_display *dp, png_store* ps, png_uint_32 id,
4970 int do_interlace, int use_update_info)
4971 {
4972 memset(dp, 0, sizeof *dp);
4973
4974 dp->ps = ps;
4975 dp->colour_type = COL_FROM_ID(id);
4976 dp->bit_depth = DEPTH_FROM_ID(id);
4977 if (dp->bit_depth < 1 || dp->bit_depth > 16)
4978 internal_error(ps, "internal: bad bit depth");
4979 if (dp->colour_type == 3)
4980 dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT = 8;
4981 else
4982 dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT =
4983 dp->bit_depth;
4984 dp->interlace_type = INTERLACE_FROM_ID(id);
4985 check_interlace_type(dp->interlace_type);
4986 dp->id = id;
4987 /* All the rest are filled in after the read_info: */
4988 dp->w = 0;
4989 dp->h = 0;
4990 dp->npasses = 0;
4991 dp->pixel_size = 0;
4992 dp->bit_width = 0;
4993 dp->cbRow = 0;
4994 dp->do_interlace = do_interlace;
4995 dp->littleendian = 0;
4996 dp->is_transparent = 0;
4997 dp->speed = ps->speed;
4998 dp->use_update_info = use_update_info;
4999 dp->npalette = 0;
5000 /* Preset the transparent color to black: */
5001 memset(&dp->transparent, 0, sizeof dp->transparent);
5002 /* Preset the palette to full intensity/opaque througout: */
5003 memset(dp->palette, 0xff, sizeof dp->palette);
5004 }
5005
5006 /* Initialize the palette fields - this must be done later because the palette
5007 * comes from the particular png_store_file that is selected.
5008 */
5009 static void
standard_palette_init(standard_display * dp)5010 standard_palette_init(standard_display *dp)
5011 {
5012 store_palette_entry *palette = store_current_palette(dp->ps, &dp->npalette);
5013
5014 /* The remaining entries remain white/opaque. */
5015 if (dp->npalette > 0)
5016 {
5017 int i = dp->npalette;
5018 memcpy(dp->palette, palette, i * sizeof *palette);
5019
5020 /* Check for a non-opaque palette entry: */
5021 while (--i >= 0)
5022 if (palette[i].alpha < 255)
5023 break;
5024
5025 # ifdef __GNUC__
5026 /* GCC can't handle the more obviously optimizable version. */
5027 if (i >= 0)
5028 dp->is_transparent = 1;
5029 else
5030 dp->is_transparent = 0;
5031 # else
5032 dp->is_transparent = (i >= 0);
5033 # endif
5034 }
5035 }
5036
5037 /* Utility to read the palette from the PNG file and convert it into
5038 * store_palette format. This returns 1 if there is any transparency in the
5039 * palette (it does not check for a transparent colour in the non-palette case.)
5040 */
5041 static int
read_palette(store_palette palette,int * npalette,png_const_structp pp,png_infop pi)5042 read_palette(store_palette palette, int *npalette, png_const_structp pp,
5043 png_infop pi)
5044 {
5045 png_colorp pal;
5046 png_bytep trans_alpha;
5047 int num;
5048
5049 pal = 0;
5050 *npalette = -1;
5051
5052 if (png_get_PLTE(pp, pi, &pal, npalette) & PNG_INFO_PLTE)
5053 {
5054 int i = *npalette;
5055
5056 if (i <= 0 || i > 256)
5057 png_error(pp, "validate: invalid PLTE count");
5058
5059 while (--i >= 0)
5060 {
5061 palette[i].red = pal[i].red;
5062 palette[i].green = pal[i].green;
5063 palette[i].blue = pal[i].blue;
5064 }
5065
5066 /* Mark the remainder of the entries with a flag value (other than
5067 * white/opaque which is the flag value stored above.)
5068 */
5069 memset(palette + *npalette, 126, (256-*npalette) * sizeof *palette);
5070 }
5071
5072 else /* !png_get_PLTE */
5073 {
5074 if (*npalette != (-1))
5075 png_error(pp, "validate: invalid PLTE result");
5076 /* But there is no palette, so record this: */
5077 *npalette = 0;
5078 memset(palette, 113, sizeof (store_palette));
5079 }
5080
5081 trans_alpha = 0;
5082 num = 2; /* force error below */
5083 if ((png_get_tRNS(pp, pi, &trans_alpha, &num, 0) & PNG_INFO_tRNS) != 0 &&
5084 (trans_alpha != NULL || num != 1/*returns 1 for a transparent color*/) &&
5085 /* Oops, if a palette tRNS gets expanded png_read_update_info (at least so
5086 * far as 1.5.4) does not remove the trans_alpha pointer, only num_trans,
5087 * so in the above call we get a success, we get a pointer (who knows what
5088 * to) and we get num_trans == 0:
5089 */
5090 !(trans_alpha != NULL && num == 0)) /* TODO: fix this in libpng. */
5091 {
5092 int i;
5093
5094 /* Any of these are crash-worthy - given the implementation of
5095 * png_get_tRNS up to 1.5 an app won't crash if it just checks the
5096 * result above and fails to check that the variables it passed have
5097 * actually been filled in! Note that if the app were to pass the
5098 * last, png_color_16p, variable too it couldn't rely on this.
5099 */
5100 if (trans_alpha == NULL || num <= 0 || num > 256 || num > *npalette)
5101 png_error(pp, "validate: unexpected png_get_tRNS (palette) result");
5102
5103 for (i=0; i<num; ++i)
5104 palette[i].alpha = trans_alpha[i];
5105
5106 for (num=*npalette; i<num; ++i)
5107 palette[i].alpha = 255;
5108
5109 for (; i<256; ++i)
5110 palette[i].alpha = 33; /* flag value */
5111
5112 return 1; /* transparency */
5113 }
5114
5115 else
5116 {
5117 /* No palette transparency - just set the alpha channel to opaque. */
5118 int i;
5119
5120 for (i=0, num=*npalette; i<num; ++i)
5121 palette[i].alpha = 255;
5122
5123 for (; i<256; ++i)
5124 palette[i].alpha = 55; /* flag value */
5125
5126 return 0; /* no transparency */
5127 }
5128 }
5129
5130 /* Utility to validate the palette if it should not have changed (the
5131 * non-transform case).
5132 */
5133 static void
standard_palette_validate(standard_display * dp,png_const_structp pp,png_infop pi)5134 standard_palette_validate(standard_display *dp, png_const_structp pp,
5135 png_infop pi)
5136 {
5137 int npalette;
5138 store_palette palette;
5139
5140 if (read_palette(palette, &npalette, pp, pi) != dp->is_transparent)
5141 png_error(pp, "validate: palette transparency changed");
5142
5143 if (npalette != dp->npalette)
5144 {
5145 size_t pos = 0;
5146 char msg[64];
5147
5148 pos = safecat(msg, sizeof msg, pos, "validate: palette size changed: ");
5149 pos = safecatn(msg, sizeof msg, pos, dp->npalette);
5150 pos = safecat(msg, sizeof msg, pos, " -> ");
5151 pos = safecatn(msg, sizeof msg, pos, npalette);
5152 png_error(pp, msg);
5153 }
5154
5155 {
5156 int i = npalette; /* npalette is aliased */
5157
5158 while (--i >= 0)
5159 if (palette[i].red != dp->palette[i].red ||
5160 palette[i].green != dp->palette[i].green ||
5161 palette[i].blue != dp->palette[i].blue ||
5162 palette[i].alpha != dp->palette[i].alpha)
5163 png_error(pp, "validate: PLTE or tRNS chunk changed");
5164 }
5165 }
5166
5167 /* By passing a 'standard_display' the progressive callbacks can be used
5168 * directly by the sequential code, the functions suffixed "_imp" are the
5169 * implementations, the functions without the suffix are the callbacks.
5170 *
5171 * The code for the info callback is split into two because this callback calls
5172 * png_read_update_info or png_start_read_image and what gets called depends on
5173 * whether the info needs updating (we want to test both calls in pngvalid.)
5174 */
5175 static void
standard_info_part1(standard_display * dp,png_structp pp,png_infop pi)5176 standard_info_part1(standard_display *dp, png_structp pp, png_infop pi)
5177 {
5178 if (png_get_bit_depth(pp, pi) != dp->bit_depth)
5179 png_error(pp, "validate: bit depth changed");
5180
5181 if (png_get_color_type(pp, pi) != dp->colour_type)
5182 png_error(pp, "validate: color type changed");
5183
5184 if (png_get_filter_type(pp, pi) != PNG_FILTER_TYPE_BASE)
5185 png_error(pp, "validate: filter type changed");
5186
5187 if (png_get_interlace_type(pp, pi) != dp->interlace_type)
5188 png_error(pp, "validate: interlacing changed");
5189
5190 if (png_get_compression_type(pp, pi) != PNG_COMPRESSION_TYPE_BASE)
5191 png_error(pp, "validate: compression type changed");
5192
5193 dp->w = png_get_image_width(pp, pi);
5194
5195 if (dp->w != standard_width(pp, dp->id))
5196 png_error(pp, "validate: image width changed");
5197
5198 dp->h = png_get_image_height(pp, pi);
5199
5200 if (dp->h != standard_height(pp, dp->id))
5201 png_error(pp, "validate: image height changed");
5202
5203 /* Record (but don't check at present) the input sBIT according to the colour
5204 * type information.
5205 */
5206 {
5207 png_color_8p sBIT = 0;
5208
5209 if (png_get_sBIT(pp, pi, &sBIT) & PNG_INFO_sBIT)
5210 {
5211 int sBIT_invalid = 0;
5212
5213 if (sBIT == 0)
5214 png_error(pp, "validate: unexpected png_get_sBIT result");
5215
5216 if (dp->colour_type & PNG_COLOR_MASK_COLOR)
5217 {
5218 if (sBIT->red == 0 || sBIT->red > dp->bit_depth)
5219 sBIT_invalid = 1;
5220 else
5221 dp->red_sBIT = sBIT->red;
5222
5223 if (sBIT->green == 0 || sBIT->green > dp->bit_depth)
5224 sBIT_invalid = 1;
5225 else
5226 dp->green_sBIT = sBIT->green;
5227
5228 if (sBIT->blue == 0 || sBIT->blue > dp->bit_depth)
5229 sBIT_invalid = 1;
5230 else
5231 dp->blue_sBIT = sBIT->blue;
5232 }
5233
5234 else /* !COLOR */
5235 {
5236 if (sBIT->gray == 0 || sBIT->gray > dp->bit_depth)
5237 sBIT_invalid = 1;
5238 else
5239 dp->blue_sBIT = dp->green_sBIT = dp->red_sBIT = sBIT->gray;
5240 }
5241
5242 /* All 8 bits in tRNS for a palette image are significant - see the
5243 * spec.
5244 */
5245 if (dp->colour_type & PNG_COLOR_MASK_ALPHA)
5246 {
5247 if (sBIT->alpha == 0 || sBIT->alpha > dp->bit_depth)
5248 sBIT_invalid = 1;
5249 else
5250 dp->alpha_sBIT = sBIT->alpha;
5251 }
5252
5253 if (sBIT_invalid)
5254 png_error(pp, "validate: sBIT value out of range");
5255 }
5256 }
5257
5258 /* Important: this is validating the value *before* any transforms have been
5259 * put in place. It doesn't matter for the standard tests, where there are
5260 * no transforms, but it does for other tests where rowbytes may change after
5261 * png_read_update_info.
5262 */
5263 if (png_get_rowbytes(pp, pi) != standard_rowsize(pp, dp->id))
5264 png_error(pp, "validate: row size changed");
5265
5266 /* Validate the colour type 3 palette (this can be present on other color
5267 * types.)
5268 */
5269 standard_palette_validate(dp, pp, pi);
5270
5271 /* In any case always check for a tranparent color (notice that the
5272 * colour type 3 case must not give a successful return on the get_tRNS call
5273 * with these arguments!)
5274 */
5275 {
5276 png_color_16p trans_color = 0;
5277
5278 if (png_get_tRNS(pp, pi, 0, 0, &trans_color) & PNG_INFO_tRNS)
5279 {
5280 if (trans_color == 0)
5281 png_error(pp, "validate: unexpected png_get_tRNS (color) result");
5282
5283 switch (dp->colour_type)
5284 {
5285 case 0:
5286 dp->transparent.red = dp->transparent.green = dp->transparent.blue =
5287 trans_color->gray;
5288 dp->has_tRNS = 1;
5289 break;
5290
5291 case 2:
5292 dp->transparent.red = trans_color->red;
5293 dp->transparent.green = trans_color->green;
5294 dp->transparent.blue = trans_color->blue;
5295 dp->has_tRNS = 1;
5296 break;
5297
5298 case 3:
5299 /* Not expected because it should result in the array case
5300 * above.
5301 */
5302 png_error(pp, "validate: unexpected png_get_tRNS result");
5303 break;
5304
5305 default:
5306 png_error(pp, "validate: invalid tRNS chunk with alpha image");
5307 }
5308 }
5309 }
5310
5311 /* Read the number of passes - expected to match the value used when
5312 * creating the image (interlaced or not). This has the side effect of
5313 * turning on interlace handling (if do_interlace is not set.)
5314 */
5315 dp->npasses = npasses_from_interlace_type(pp, dp->interlace_type);
5316 if (!dp->do_interlace)
5317 {
5318 # ifdef PNG_READ_INTERLACING_SUPPORTED
5319 if (dp->npasses != png_set_interlace_handling(pp))
5320 png_error(pp, "validate: file changed interlace type");
5321 # else /* !READ_INTERLACING */
5322 /* This should never happen: the relevant tests (!do_interlace) should
5323 * not be run.
5324 */
5325 if (dp->npasses > 1)
5326 png_error(pp, "validate: no libpng interlace support");
5327 # endif /* !READ_INTERLACING */
5328 }
5329
5330 /* Caller calls png_read_update_info or png_start_read_image now, then calls
5331 * part2.
5332 */
5333 }
5334
5335 /* This must be called *after* the png_read_update_info call to get the correct
5336 * 'rowbytes' value, otherwise png_get_rowbytes will refer to the untransformed
5337 * image.
5338 */
5339 static void
standard_info_part2(standard_display * dp,png_const_structp pp,png_const_infop pi,int nImages)5340 standard_info_part2(standard_display *dp, png_const_structp pp,
5341 png_const_infop pi, int nImages)
5342 {
5343 /* Record cbRow now that it can be found. */
5344 {
5345 png_byte ct = png_get_color_type(pp, pi);
5346 png_byte bd = png_get_bit_depth(pp, pi);
5347
5348 if (bd >= 8 && (ct == PNG_COLOR_TYPE_RGB || ct == PNG_COLOR_TYPE_GRAY) &&
5349 dp->filler)
5350 ct |= 4; /* handle filler as faked alpha channel */
5351
5352 dp->pixel_size = bit_size(pp, ct, bd);
5353 }
5354 dp->bit_width = png_get_image_width(pp, pi) * dp->pixel_size;
5355 dp->cbRow = png_get_rowbytes(pp, pi);
5356
5357 /* Validate the rowbytes here again. */
5358 if (dp->cbRow != (dp->bit_width+7)/8)
5359 png_error(pp, "bad png_get_rowbytes calculation");
5360
5361 /* Then ensure there is enough space for the output image(s). */
5362 store_ensure_image(dp->ps, pp, nImages, dp->cbRow, dp->h);
5363 }
5364
5365 static void
standard_info_imp(standard_display * dp,png_structp pp,png_infop pi,int nImages)5366 standard_info_imp(standard_display *dp, png_structp pp, png_infop pi,
5367 int nImages)
5368 {
5369 /* Note that the validation routine has the side effect of turning on
5370 * interlace handling in the subsequent code.
5371 */
5372 standard_info_part1(dp, pp, pi);
5373
5374 /* And the info callback has to call this (or png_read_update_info - see
5375 * below in the png_modifier code for that variant.
5376 */
5377 if (dp->use_update_info)
5378 {
5379 /* For debugging the effect of multiple calls: */
5380 int i = dp->use_update_info;
5381 while (i-- > 0)
5382 png_read_update_info(pp, pi);
5383 }
5384
5385 else
5386 png_start_read_image(pp);
5387
5388 /* Validate the height, width and rowbytes plus ensure that sufficient buffer
5389 * exists for decoding the image.
5390 */
5391 standard_info_part2(dp, pp, pi, nImages);
5392 }
5393
5394 static void PNGCBAPI
standard_info(png_structp pp,png_infop pi)5395 standard_info(png_structp pp, png_infop pi)
5396 {
5397 standard_display *dp = voidcast(standard_display*,
5398 png_get_progressive_ptr(pp));
5399
5400 /* Call with nImages==1 because the progressive reader can only produce one
5401 * image.
5402 */
5403 standard_info_imp(dp, pp, pi, 1 /*only one image*/);
5404 }
5405
5406 static void PNGCBAPI
progressive_row(png_structp ppIn,png_bytep new_row,png_uint_32 y,int pass)5407 progressive_row(png_structp ppIn, png_bytep new_row, png_uint_32 y, int pass)
5408 {
5409 png_const_structp pp = ppIn;
5410 const standard_display *dp = voidcast(standard_display*,
5411 png_get_progressive_ptr(pp));
5412
5413 /* When handling interlacing some rows will be absent in each pass, the
5414 * callback still gets called, but with a NULL pointer. This is checked
5415 * in the 'else' clause below. We need our own 'cbRow', but we can't call
5416 * png_get_rowbytes because we got no info structure.
5417 */
5418 if (new_row != NULL)
5419 {
5420 png_bytep row;
5421
5422 /* In the case where the reader doesn't do the interlace it gives
5423 * us the y in the sub-image:
5424 */
5425 if (dp->do_interlace && dp->interlace_type == PNG_INTERLACE_ADAM7)
5426 {
5427 #ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
5428 /* Use this opportunity to validate the png 'current' APIs: */
5429 if (y != png_get_current_row_number(pp))
5430 png_error(pp, "png_get_current_row_number is broken");
5431
5432 if (pass != png_get_current_pass_number(pp))
5433 png_error(pp, "png_get_current_pass_number is broken");
5434 #endif /* USER_TRANSFORM_INFO */
5435
5436 y = PNG_ROW_FROM_PASS_ROW(y, pass);
5437 }
5438
5439 /* Validate this just in case. */
5440 if (y >= dp->h)
5441 png_error(pp, "invalid y to progressive row callback");
5442
5443 row = store_image_row(dp->ps, pp, 0, y);
5444
5445 /* Combine the new row into the old: */
5446 #ifdef PNG_READ_INTERLACING_SUPPORTED
5447 if (dp->do_interlace)
5448 #endif /* READ_INTERLACING */
5449 {
5450 if (dp->interlace_type == PNG_INTERLACE_ADAM7)
5451 deinterlace_row(row, new_row, dp->pixel_size, dp->w, pass,
5452 dp->littleendian);
5453 else
5454 row_copy(row, new_row, dp->pixel_size * dp->w, dp->littleendian);
5455 }
5456 #ifdef PNG_READ_INTERLACING_SUPPORTED
5457 else
5458 png_progressive_combine_row(pp, row, new_row);
5459 #endif /* PNG_READ_INTERLACING_SUPPORTED */
5460 }
5461
5462 else if (dp->interlace_type == PNG_INTERLACE_ADAM7 &&
5463 PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
5464 PNG_PASS_COLS(dp->w, pass) > 0)
5465 png_error(pp, "missing row in progressive de-interlacing");
5466 }
5467
5468 static void
sequential_row(standard_display * dp,png_structp pp,png_infop pi,const int iImage,const int iDisplay)5469 sequential_row(standard_display *dp, png_structp pp, png_infop pi,
5470 const int iImage, const int iDisplay)
5471 {
5472 const int npasses = dp->npasses;
5473 const int do_interlace = dp->do_interlace &&
5474 dp->interlace_type == PNG_INTERLACE_ADAM7;
5475 const png_uint_32 height = standard_height(pp, dp->id);
5476 const png_uint_32 width = standard_width(pp, dp->id);
5477 const png_store* ps = dp->ps;
5478 int pass;
5479
5480 for (pass=0; pass<npasses; ++pass)
5481 {
5482 png_uint_32 y;
5483 png_uint_32 wPass = PNG_PASS_COLS(width, pass);
5484
5485 for (y=0; y<height; ++y)
5486 {
5487 if (do_interlace)
5488 {
5489 /* wPass may be zero or this row may not be in this pass.
5490 * png_read_row must not be called in either case.
5491 */
5492 if (wPass > 0 && PNG_ROW_IN_INTERLACE_PASS(y, pass))
5493 {
5494 /* Read the row into a pair of temporary buffers, then do the
5495 * merge here into the output rows.
5496 */
5497 png_byte row[STANDARD_ROWMAX], display[STANDARD_ROWMAX];
5498
5499 /* The following aids (to some extent) error detection - we can
5500 * see where png_read_row wrote. Use opposite values in row and
5501 * display to make this easier. Don't use 0xff (which is used in
5502 * the image write code to fill unused bits) or 0 (which is a
5503 * likely value to overwrite unused bits with).
5504 */
5505 memset(row, 0xc5, sizeof row);
5506 memset(display, 0x5c, sizeof display);
5507
5508 png_read_row(pp, row, display);
5509
5510 if (iImage >= 0)
5511 deinterlace_row(store_image_row(ps, pp, iImage, y), row,
5512 dp->pixel_size, dp->w, pass, dp->littleendian);
5513
5514 if (iDisplay >= 0)
5515 deinterlace_row(store_image_row(ps, pp, iDisplay, y), display,
5516 dp->pixel_size, dp->w, pass, dp->littleendian);
5517 }
5518 }
5519 else
5520 png_read_row(pp,
5521 iImage >= 0 ? store_image_row(ps, pp, iImage, y) : NULL,
5522 iDisplay >= 0 ? store_image_row(ps, pp, iDisplay, y) : NULL);
5523 }
5524 }
5525
5526 /* And finish the read operation (only really necessary if the caller wants
5527 * to find additional data in png_info from chunks after the last IDAT.)
5528 */
5529 png_read_end(pp, pi);
5530 }
5531
5532 #ifdef PNG_TEXT_SUPPORTED
5533 static void
standard_check_text(png_const_structp pp,png_const_textp tp,png_const_charp keyword,png_const_charp text)5534 standard_check_text(png_const_structp pp, png_const_textp tp,
5535 png_const_charp keyword, png_const_charp text)
5536 {
5537 char msg[1024];
5538 size_t pos = safecat(msg, sizeof msg, 0, "text: ");
5539 size_t ok;
5540
5541 pos = safecat(msg, sizeof msg, pos, keyword);
5542 pos = safecat(msg, sizeof msg, pos, ": ");
5543 ok = pos;
5544
5545 if (tp->compression != TEXT_COMPRESSION)
5546 {
5547 char buf[64];
5548
5549 sprintf(buf, "compression [%d->%d], ", TEXT_COMPRESSION,
5550 tp->compression);
5551 pos = safecat(msg, sizeof msg, pos, buf);
5552 }
5553
5554 if (tp->key == NULL || strcmp(tp->key, keyword) != 0)
5555 {
5556 pos = safecat(msg, sizeof msg, pos, "keyword \"");
5557 if (tp->key != NULL)
5558 {
5559 pos = safecat(msg, sizeof msg, pos, tp->key);
5560 pos = safecat(msg, sizeof msg, pos, "\", ");
5561 }
5562
5563 else
5564 pos = safecat(msg, sizeof msg, pos, "null, ");
5565 }
5566
5567 if (tp->text == NULL)
5568 pos = safecat(msg, sizeof msg, pos, "text lost, ");
5569
5570 else
5571 {
5572 if (tp->text_length != strlen(text))
5573 {
5574 char buf[64];
5575 sprintf(buf, "text length changed[%lu->%lu], ",
5576 (unsigned long)strlen(text), (unsigned long)tp->text_length);
5577 pos = safecat(msg, sizeof msg, pos, buf);
5578 }
5579
5580 if (strcmp(tp->text, text) != 0)
5581 {
5582 pos = safecat(msg, sizeof msg, pos, "text becomes \"");
5583 pos = safecat(msg, sizeof msg, pos, tp->text);
5584 pos = safecat(msg, sizeof msg, pos, "\" (was \"");
5585 pos = safecat(msg, sizeof msg, pos, text);
5586 pos = safecat(msg, sizeof msg, pos, "\"), ");
5587 }
5588 }
5589
5590 if (tp->itxt_length != 0)
5591 pos = safecat(msg, sizeof msg, pos, "iTXt length set, ");
5592
5593 if (tp->lang != NULL)
5594 {
5595 pos = safecat(msg, sizeof msg, pos, "iTXt language \"");
5596 pos = safecat(msg, sizeof msg, pos, tp->lang);
5597 pos = safecat(msg, sizeof msg, pos, "\", ");
5598 }
5599
5600 if (tp->lang_key != NULL)
5601 {
5602 pos = safecat(msg, sizeof msg, pos, "iTXt keyword \"");
5603 pos = safecat(msg, sizeof msg, pos, tp->lang_key);
5604 pos = safecat(msg, sizeof msg, pos, "\", ");
5605 }
5606
5607 if (pos > ok)
5608 {
5609 msg[pos-2] = '\0'; /* Remove the ", " at the end */
5610 png_error(pp, msg);
5611 }
5612 }
5613
5614 static void
standard_text_validate(standard_display * dp,png_const_structp pp,png_infop pi,int check_end)5615 standard_text_validate(standard_display *dp, png_const_structp pp,
5616 png_infop pi, int check_end)
5617 {
5618 png_textp tp = NULL;
5619 png_uint_32 num_text = png_get_text(pp, pi, &tp, NULL);
5620
5621 if (num_text == 2 && tp != NULL)
5622 {
5623 standard_check_text(pp, tp, "image name", dp->ps->current->name);
5624
5625 /* This exists because prior to 1.5.18 the progressive reader left the
5626 * png_struct z_stream unreset at the end of the image, so subsequent
5627 * attempts to use it simply returns Z_STREAM_END.
5628 */
5629 if (check_end)
5630 standard_check_text(pp, tp+1, "end marker", "end");
5631 }
5632
5633 else
5634 {
5635 char msg[64];
5636
5637 sprintf(msg, "expected two text items, got %lu",
5638 (unsigned long)num_text);
5639 png_error(pp, msg);
5640 }
5641 }
5642 #else
5643 # define standard_text_validate(dp,pp,pi,check_end) ((void)0)
5644 #endif
5645
5646 static void
standard_row_validate(standard_display * dp,png_const_structp pp,int iImage,int iDisplay,png_uint_32 y)5647 standard_row_validate(standard_display *dp, png_const_structp pp,
5648 int iImage, int iDisplay, png_uint_32 y)
5649 {
5650 int where;
5651 png_byte std[STANDARD_ROWMAX];
5652
5653 /* The row must be pre-initialized to the magic number here for the size
5654 * tests to pass:
5655 */
5656 memset(std, 178, sizeof std);
5657 standard_row(pp, std, dp->id, y);
5658
5659 /* At the end both the 'row' and 'display' arrays should end up identical.
5660 * In earlier passes 'row' will be partially filled in, with only the pixels
5661 * that have been read so far, but 'display' will have those pixels
5662 * replicated to fill the unread pixels while reading an interlaced image.
5663 */
5664 if (iImage >= 0 &&
5665 (where = pixel_cmp(std, store_image_row(dp->ps, pp, iImage, y),
5666 dp->bit_width)) != 0)
5667 {
5668 char msg[64];
5669 sprintf(msg, "PNG image row[%lu][%d] changed from %.2x to %.2x",
5670 (unsigned long)y, where-1, std[where-1],
5671 store_image_row(dp->ps, pp, iImage, y)[where-1]);
5672 png_error(pp, msg);
5673 }
5674
5675 if (iDisplay >= 0 &&
5676 (where = pixel_cmp(std, store_image_row(dp->ps, pp, iDisplay, y),
5677 dp->bit_width)) != 0)
5678 {
5679 char msg[64];
5680 sprintf(msg, "display row[%lu][%d] changed from %.2x to %.2x",
5681 (unsigned long)y, where-1, std[where-1],
5682 store_image_row(dp->ps, pp, iDisplay, y)[where-1]);
5683 png_error(pp, msg);
5684 }
5685 }
5686
5687 static void
standard_image_validate(standard_display * dp,png_const_structp pp,int iImage,int iDisplay)5688 standard_image_validate(standard_display *dp, png_const_structp pp, int iImage,
5689 int iDisplay)
5690 {
5691 png_uint_32 y;
5692
5693 if (iImage >= 0)
5694 store_image_check(dp->ps, pp, iImage);
5695
5696 if (iDisplay >= 0)
5697 store_image_check(dp->ps, pp, iDisplay);
5698
5699 for (y=0; y<dp->h; ++y)
5700 standard_row_validate(dp, pp, iImage, iDisplay, y);
5701
5702 /* This avoids false positives if the validation code is never called! */
5703 dp->ps->validated = 1;
5704 }
5705
5706 static void PNGCBAPI
standard_end(png_structp ppIn,png_infop pi)5707 standard_end(png_structp ppIn, png_infop pi)
5708 {
5709 png_const_structp pp = ppIn;
5710 standard_display *dp = voidcast(standard_display*,
5711 png_get_progressive_ptr(pp));
5712
5713 UNUSED(pi)
5714
5715 /* Validate the image - progressive reading only produces one variant for
5716 * interlaced images.
5717 */
5718 standard_text_validate(dp, pp, pi,
5719 PNG_LIBPNG_VER >= 10518/*check_end: see comments above*/);
5720 standard_image_validate(dp, pp, 0, -1);
5721 }
5722
5723 /* A single test run checking the standard image to ensure it is not damaged. */
5724 static void
standard_test(png_store * const psIn,png_uint_32 const id,int do_interlace,int use_update_info)5725 standard_test(png_store* const psIn, png_uint_32 const id,
5726 int do_interlace, int use_update_info)
5727 {
5728 standard_display d;
5729 context(psIn, fault);
5730
5731 /* Set up the display (stack frame) variables from the arguments to the
5732 * function and initialize the locals that are filled in later.
5733 */
5734 standard_display_init(&d, psIn, id, do_interlace, use_update_info);
5735
5736 /* Everything is protected by a Try/Catch. The functions called also
5737 * typically have local Try/Catch blocks.
5738 */
5739 Try
5740 {
5741 png_structp pp;
5742 png_infop pi;
5743
5744 /* Get a png_struct for reading the image. This will throw an error if it
5745 * fails, so we don't need to check the result.
5746 */
5747 pp = set_store_for_read(d.ps, &pi, d.id,
5748 d.do_interlace ? (d.ps->progressive ?
5749 "pngvalid progressive deinterlacer" :
5750 "pngvalid sequential deinterlacer") : (d.ps->progressive ?
5751 "progressive reader" : "sequential reader"));
5752
5753 /* Initialize the palette correctly from the png_store_file. */
5754 standard_palette_init(&d);
5755
5756 /* Introduce the correct read function. */
5757 if (d.ps->progressive)
5758 {
5759 png_set_progressive_read_fn(pp, &d, standard_info, progressive_row,
5760 standard_end);
5761
5762 /* Now feed data into the reader until we reach the end: */
5763 store_progressive_read(d.ps, pp, pi);
5764 }
5765 else
5766 {
5767 /* Note that this takes the store, not the display. */
5768 png_set_read_fn(pp, d.ps, store_read);
5769
5770 /* Check the header values: */
5771 png_read_info(pp, pi);
5772
5773 /* The code tests both versions of the images that the sequential
5774 * reader can produce.
5775 */
5776 standard_info_imp(&d, pp, pi, 2 /*images*/);
5777
5778 /* Need the total bytes in the image below; we can't get to this point
5779 * unless the PNG file values have been checked against the expected
5780 * values.
5781 */
5782 {
5783 sequential_row(&d, pp, pi, 0, 1);
5784
5785 /* After the last pass loop over the rows again to check that the
5786 * image is correct.
5787 */
5788 if (!d.speed)
5789 {
5790 standard_text_validate(&d, pp, pi, 1/*check_end*/);
5791 standard_image_validate(&d, pp, 0, 1);
5792 }
5793 else
5794 d.ps->validated = 1;
5795 }
5796 }
5797
5798 /* Check for validation. */
5799 if (!d.ps->validated)
5800 png_error(pp, "image read failed silently");
5801
5802 /* Successful completion. */
5803 }
5804
5805 Catch(fault)
5806 d.ps = fault; /* make sure this hasn't been clobbered. */
5807
5808 /* In either case clean up the store. */
5809 store_read_reset(d.ps);
5810 }
5811
5812 static int
test_standard(png_modifier * const pm,png_byte const colour_type,int bdlo,int const bdhi)5813 test_standard(png_modifier* const pm, png_byte const colour_type,
5814 int bdlo, int const bdhi)
5815 {
5816 for (; bdlo <= bdhi; ++bdlo)
5817 {
5818 int interlace_type;
5819
5820 for (interlace_type = PNG_INTERLACE_NONE;
5821 interlace_type < INTERLACE_LAST; ++interlace_type)
5822 {
5823 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5824 interlace_type, 0, 0, 0), do_read_interlace, pm->use_update_info);
5825
5826 if (fail(pm))
5827 return 0;
5828 }
5829 }
5830
5831 return 1; /* keep going */
5832 }
5833
5834 static void
perform_standard_test(png_modifier * pm)5835 perform_standard_test(png_modifier *pm)
5836 {
5837 /* Test each colour type over the valid range of bit depths (expressed as
5838 * log2(bit_depth) in turn, stop as soon as any error is detected.
5839 */
5840 if (!test_standard(pm, 0, 0, READ_BDHI))
5841 return;
5842
5843 if (!test_standard(pm, 2, 3, READ_BDHI))
5844 return;
5845
5846 if (!test_standard(pm, 3, 0, 3))
5847 return;
5848
5849 if (!test_standard(pm, 4, 3, READ_BDHI))
5850 return;
5851
5852 if (!test_standard(pm, 6, 3, READ_BDHI))
5853 return;
5854 }
5855
5856
5857 /********************************** SIZE TESTS ********************************/
5858 static int
test_size(png_modifier * const pm,png_byte const colour_type,int bdlo,int const bdhi)5859 test_size(png_modifier* const pm, png_byte const colour_type,
5860 int bdlo, int const bdhi)
5861 {
5862 /* Run the tests on each combination.
5863 *
5864 * NOTE: on my 32 bit x86 each of the following blocks takes
5865 * a total of 3.5 seconds if done across every combo of bit depth
5866 * width and height. This is a waste of time in practice, hence the
5867 * hinc and winc stuff:
5868 */
5869 static const png_byte hinc[] = {1, 3, 11, 1, 5};
5870 static const png_byte winc[] = {1, 9, 5, 7, 1};
5871 const int save_bdlo = bdlo;
5872
5873 for (; bdlo <= bdhi; ++bdlo)
5874 {
5875 png_uint_32 h, w;
5876
5877 for (h=1; h<=16; h+=hinc[bdlo]) for (w=1; w<=16; w+=winc[bdlo])
5878 {
5879 /* First test all the 'size' images against the sequential
5880 * reader using libpng to deinterlace (where required.) This
5881 * validates the write side of libpng. There are four possibilities
5882 * to validate.
5883 */
5884 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5885 PNG_INTERLACE_NONE, w, h, 0), 0/*do_interlace*/,
5886 pm->use_update_info);
5887
5888 if (fail(pm))
5889 return 0;
5890
5891 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5892 PNG_INTERLACE_NONE, w, h, 1), 0/*do_interlace*/,
5893 pm->use_update_info);
5894
5895 if (fail(pm))
5896 return 0;
5897
5898 /* Now validate the interlaced read side - do_interlace true,
5899 * in the progressive case this does actually make a difference
5900 * to the code used in the non-interlaced case too.
5901 */
5902 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5903 PNG_INTERLACE_NONE, w, h, 0), 1/*do_interlace*/,
5904 pm->use_update_info);
5905
5906 if (fail(pm))
5907 return 0;
5908
5909 # if CAN_WRITE_INTERLACE
5910 /* Validate the pngvalid code itself: */
5911 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5912 PNG_INTERLACE_ADAM7, w, h, 1), 1/*do_interlace*/,
5913 pm->use_update_info);
5914
5915 if (fail(pm))
5916 return 0;
5917 # endif
5918 }
5919 }
5920
5921 /* Now do the tests of libpng interlace handling, after we have made sure
5922 * that the pngvalid version works:
5923 */
5924 for (bdlo = save_bdlo; bdlo <= bdhi; ++bdlo)
5925 {
5926 png_uint_32 h, w;
5927
5928 for (h=1; h<=16; h+=hinc[bdlo]) for (w=1; w<=16; w+=winc[bdlo])
5929 {
5930 # ifdef PNG_READ_INTERLACING_SUPPORTED
5931 /* Test with pngvalid generated interlaced images first; we have
5932 * already verify these are ok (unless pngvalid has self-consistent
5933 * read/write errors, which is unlikely), so this detects errors in the
5934 * read side first:
5935 */
5936 # if CAN_WRITE_INTERLACE
5937 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5938 PNG_INTERLACE_ADAM7, w, h, 1), 0/*do_interlace*/,
5939 pm->use_update_info);
5940
5941 if (fail(pm))
5942 return 0;
5943 # endif
5944 # endif /* READ_INTERLACING */
5945
5946 # ifdef PNG_WRITE_INTERLACING_SUPPORTED
5947 /* Test the libpng write side against the pngvalid read side: */
5948 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5949 PNG_INTERLACE_ADAM7, w, h, 0), 1/*do_interlace*/,
5950 pm->use_update_info);
5951
5952 if (fail(pm))
5953 return 0;
5954 # endif
5955
5956 # ifdef PNG_READ_INTERLACING_SUPPORTED
5957 # ifdef PNG_WRITE_INTERLACING_SUPPORTED
5958 /* Test both together: */
5959 standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
5960 PNG_INTERLACE_ADAM7, w, h, 0), 0/*do_interlace*/,
5961 pm->use_update_info);
5962
5963 if (fail(pm))
5964 return 0;
5965 # endif
5966 # endif /* READ_INTERLACING */
5967 }
5968 }
5969
5970 return 1; /* keep going */
5971 }
5972
5973 static void
perform_size_test(png_modifier * pm)5974 perform_size_test(png_modifier *pm)
5975 {
5976 /* Test each colour type over the valid range of bit depths (expressed as
5977 * log2(bit_depth) in turn, stop as soon as any error is detected.
5978 */
5979 if (!test_size(pm, 0, 0, READ_BDHI))
5980 return;
5981
5982 if (!test_size(pm, 2, 3, READ_BDHI))
5983 return;
5984
5985 /* For the moment don't do the palette test - it's a waste of time when
5986 * compared to the grayscale test.
5987 */
5988 #if 0
5989 if (!test_size(pm, 3, 0, 3))
5990 return;
5991 #endif
5992
5993 if (!test_size(pm, 4, 3, READ_BDHI))
5994 return;
5995
5996 if (!test_size(pm, 6, 3, READ_BDHI))
5997 return;
5998 }
5999
6000
6001 /******************************* TRANSFORM TESTS ******************************/
6002 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
6003 /* A set of tests to validate libpng image transforms. The possibilities here
6004 * are legion because the transforms can be combined in a combinatorial
6005 * fashion. To deal with this some measure of restraint is required, otherwise
6006 * the tests would take forever.
6007 */
6008 typedef struct image_pixel
6009 {
6010 /* A local (pngvalid) representation of a PNG pixel, in all its
6011 * various forms.
6012 */
6013 unsigned int red, green, blue, alpha; /* For non-palette images. */
6014 unsigned int palette_index; /* For a palette image. */
6015 png_byte colour_type; /* As in the spec. */
6016 png_byte bit_depth; /* Defines bit size in row */
6017 png_byte sample_depth; /* Scale of samples */
6018 unsigned int have_tRNS :1; /* tRNS chunk may need processing */
6019 unsigned int swap_rgb :1; /* RGB swapped to BGR */
6020 unsigned int alpha_first :1; /* Alpha at start, not end */
6021 unsigned int alpha_inverted :1; /* Alpha channel inverted */
6022 unsigned int mono_inverted :1; /* Gray channel inverted */
6023 unsigned int swap16 :1; /* Byte swap 16-bit components */
6024 unsigned int littleendian :1; /* High bits on right */
6025 unsigned int sig_bits :1; /* Pixel shifted (sig bits only) */
6026
6027 /* For checking the code calculates double precision floating point values
6028 * along with an error value, accumulated from the transforms. Because an
6029 * sBIT setting allows larger error bounds (indeed, by the spec, apparently
6030 * up to just less than +/-1 in the scaled value) the *lowest* sBIT for each
6031 * channel is stored. This sBIT value is folded in to the stored error value
6032 * at the end of the application of the transforms to the pixel.
6033 *
6034 * If sig_bits is set above the red, green, blue and alpha values have been
6035 * scaled so they only contain the significant bits of the component values.
6036 */
6037 double redf, greenf, bluef, alphaf;
6038 double rede, greene, bluee, alphae;
6039 png_byte red_sBIT, green_sBIT, blue_sBIT, alpha_sBIT;
6040 } image_pixel;
6041
6042 /* Shared utility function, see below. */
6043 static void
image_pixel_setf(image_pixel * this,unsigned int rMax,unsigned int gMax,unsigned int bMax,unsigned int aMax)6044 image_pixel_setf(image_pixel *this, unsigned int rMax, unsigned int gMax,
6045 unsigned int bMax, unsigned int aMax)
6046 {
6047 this->redf = this->red / (double)rMax;
6048 this->greenf = this->green / (double)gMax;
6049 this->bluef = this->blue / (double)bMax;
6050 this->alphaf = this->alpha / (double)aMax;
6051
6052 if (this->red < rMax)
6053 this->rede = this->redf * DBL_EPSILON;
6054 else
6055 this->rede = 0;
6056 if (this->green < gMax)
6057 this->greene = this->greenf * DBL_EPSILON;
6058 else
6059 this->greene = 0;
6060 if (this->blue < bMax)
6061 this->bluee = this->bluef * DBL_EPSILON;
6062 else
6063 this->bluee = 0;
6064 if (this->alpha < aMax)
6065 this->alphae = this->alphaf * DBL_EPSILON;
6066 else
6067 this->alphae = 0;
6068 }
6069
6070 /* Initialize the structure for the next pixel - call this before doing any
6071 * transforms and call it for each pixel since all the fields may need to be
6072 * reset.
6073 */
6074 static void
image_pixel_init(image_pixel * this,png_const_bytep row,png_byte colour_type,png_byte bit_depth,png_uint_32 x,store_palette palette,const image_pixel * format)6075 image_pixel_init(image_pixel *this, png_const_bytep row, png_byte colour_type,
6076 png_byte bit_depth, png_uint_32 x, store_palette palette,
6077 const image_pixel *format /*from pngvalid transform of input*/)
6078 {
6079 const png_byte sample_depth = (png_byte)(colour_type ==
6080 PNG_COLOR_TYPE_PALETTE ? 8 : bit_depth);
6081 const unsigned int max = (1U<<sample_depth)-1;
6082 const int swap16 = (format != 0 && format->swap16);
6083 const int littleendian = (format != 0 && format->littleendian);
6084 const int sig_bits = (format != 0 && format->sig_bits);
6085
6086 /* Initially just set everything to the same number and the alpha to opaque.
6087 * Note that this currently assumes a simple palette where entry x has colour
6088 * rgb(x,x,x)!
6089 */
6090 this->palette_index = this->red = this->green = this->blue =
6091 sample(row, colour_type, bit_depth, x, 0, swap16, littleendian);
6092 this->alpha = max;
6093 this->red_sBIT = this->green_sBIT = this->blue_sBIT = this->alpha_sBIT =
6094 sample_depth;
6095
6096 /* Then override as appropriate: */
6097 if (colour_type == 3) /* palette */
6098 {
6099 /* This permits the caller to default to the sample value. */
6100 if (palette != 0)
6101 {
6102 const unsigned int i = this->palette_index;
6103
6104 this->red = palette[i].red;
6105 this->green = palette[i].green;
6106 this->blue = palette[i].blue;
6107 this->alpha = palette[i].alpha;
6108 }
6109 }
6110
6111 else /* not palette */
6112 {
6113 unsigned int i = 0;
6114
6115 if ((colour_type & 4) != 0 && format != 0 && format->alpha_first)
6116 {
6117 this->alpha = this->red;
6118 /* This handles the gray case for 'AG' pixels */
6119 this->palette_index = this->red = this->green = this->blue =
6120 sample(row, colour_type, bit_depth, x, 1, swap16, littleendian);
6121 i = 1;
6122 }
6123
6124 if (colour_type & 2)
6125 {
6126 /* Green is second for both BGR and RGB: */
6127 this->green = sample(row, colour_type, bit_depth, x, ++i, swap16,
6128 littleendian);
6129
6130 if (format != 0 && format->swap_rgb) /* BGR */
6131 this->red = sample(row, colour_type, bit_depth, x, ++i, swap16,
6132 littleendian);
6133 else
6134 this->blue = sample(row, colour_type, bit_depth, x, ++i, swap16,
6135 littleendian);
6136 }
6137
6138 else /* grayscale */ if (format != 0 && format->mono_inverted)
6139 this->red = this->green = this->blue = this->red ^ max;
6140
6141 if ((colour_type & 4) != 0) /* alpha */
6142 {
6143 if (format == 0 || !format->alpha_first)
6144 this->alpha = sample(row, colour_type, bit_depth, x, ++i, swap16,
6145 littleendian);
6146
6147 if (format != 0 && format->alpha_inverted)
6148 this->alpha ^= max;
6149 }
6150 }
6151
6152 /* Calculate the scaled values, these are simply the values divided by
6153 * 'max' and the error is initialized to the double precision epsilon value
6154 * from the header file.
6155 */
6156 image_pixel_setf(this,
6157 sig_bits ? (1U << format->red_sBIT)-1 : max,
6158 sig_bits ? (1U << format->green_sBIT)-1 : max,
6159 sig_bits ? (1U << format->blue_sBIT)-1 : max,
6160 sig_bits ? (1U << format->alpha_sBIT)-1 : max);
6161
6162 /* Store the input information for use in the transforms - these will
6163 * modify the information.
6164 */
6165 this->colour_type = colour_type;
6166 this->bit_depth = bit_depth;
6167 this->sample_depth = sample_depth;
6168 this->have_tRNS = 0;
6169 this->swap_rgb = 0;
6170 this->alpha_first = 0;
6171 this->alpha_inverted = 0;
6172 this->mono_inverted = 0;
6173 this->swap16 = 0;
6174 this->littleendian = 0;
6175 this->sig_bits = 0;
6176 }
6177
6178 #if defined PNG_READ_EXPAND_SUPPORTED || defined PNG_READ_GRAY_TO_RGB_SUPPORTED\
6179 || defined PNG_READ_EXPAND_SUPPORTED || defined PNG_READ_EXPAND_16_SUPPORTED\
6180 || defined PNG_READ_BACKGROUND_SUPPORTED
6181 /* Convert a palette image to an rgb image. This necessarily converts the tRNS
6182 * chunk at the same time, because the tRNS will be in palette form. The way
6183 * palette validation works means that the original palette is never updated,
6184 * instead the image_pixel value from the row contains the RGB of the
6185 * corresponding palette entry and *this* is updated. Consequently this routine
6186 * only needs to change the colour type information.
6187 */
6188 static void
image_pixel_convert_PLTE(image_pixel * this)6189 image_pixel_convert_PLTE(image_pixel *this)
6190 {
6191 if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
6192 {
6193 if (this->have_tRNS)
6194 {
6195 this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
6196 this->have_tRNS = 0;
6197 }
6198 else
6199 this->colour_type = PNG_COLOR_TYPE_RGB;
6200
6201 /* The bit depth of the row changes at this point too (notice that this is
6202 * the row format, not the sample depth, which is separate.)
6203 */
6204 this->bit_depth = 8;
6205 }
6206 }
6207
6208 /* Add an alpha channel; this will import the tRNS information because tRNS is
6209 * not valid in an alpha image. The bit depth will invariably be set to at
6210 * least 8 prior to 1.7.0. Palette images will be converted to alpha (using
6211 * the above API). With png_set_background the alpha channel is never expanded
6212 * but this routine is used by pngvalid to simplify code; 'for_background'
6213 * records this.
6214 */
6215 static void
image_pixel_add_alpha(image_pixel * this,const standard_display * display,int for_background)6216 image_pixel_add_alpha(image_pixel *this, const standard_display *display,
6217 int for_background)
6218 {
6219 if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
6220 image_pixel_convert_PLTE(this);
6221
6222 if ((this->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
6223 {
6224 if (this->colour_type == PNG_COLOR_TYPE_GRAY)
6225 {
6226 # if PNG_LIBPNG_VER < 10700
6227 if (!for_background && this->bit_depth < 8)
6228 this->bit_depth = this->sample_depth = 8;
6229 # endif
6230
6231 if (this->have_tRNS)
6232 {
6233 /* After 1.7 the expansion of bit depth only happens if there is a
6234 * tRNS chunk to expand at this point.
6235 */
6236 # if PNG_LIBPNG_VER >= 10700
6237 if (!for_background && this->bit_depth < 8)
6238 this->bit_depth = this->sample_depth = 8;
6239 # endif
6240
6241 this->have_tRNS = 0;
6242
6243 /* Check the input, original, channel value here against the
6244 * original tRNS gray chunk valie.
6245 */
6246 if (this->red == display->transparent.red)
6247 this->alphaf = 0;
6248 else
6249 this->alphaf = 1;
6250 }
6251 else
6252 this->alphaf = 1;
6253
6254 this->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
6255 }
6256
6257 else if (this->colour_type == PNG_COLOR_TYPE_RGB)
6258 {
6259 if (this->have_tRNS)
6260 {
6261 this->have_tRNS = 0;
6262
6263 /* Again, check the exact input values, not the current transformed
6264 * value!
6265 */
6266 if (this->red == display->transparent.red &&
6267 this->green == display->transparent.green &&
6268 this->blue == display->transparent.blue)
6269 this->alphaf = 0;
6270 else
6271 this->alphaf = 1;
6272 }
6273 else
6274 this->alphaf = 1;
6275
6276 this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
6277 }
6278
6279 /* The error in the alpha is zero and the sBIT value comes from the
6280 * original sBIT data (actually it will always be the original bit depth).
6281 */
6282 this->alphae = 0;
6283 this->alpha_sBIT = display->alpha_sBIT;
6284 }
6285 }
6286 #endif /* transforms that need image_pixel_add_alpha */
6287
6288 struct transform_display;
6289 typedef struct image_transform
6290 {
6291 /* The name of this transform: a string. */
6292 const char *name;
6293
6294 /* Each transform can be disabled from the command line: */
6295 int enable;
6296
6297 /* The global list of transforms; read only. */
6298 struct image_transform *const list;
6299
6300 /* The global count of the number of times this transform has been set on an
6301 * image.
6302 */
6303 unsigned int global_use;
6304
6305 /* The local count of the number of times this transform has been set. */
6306 unsigned int local_use;
6307
6308 /* The next transform in the list, each transform must call its own next
6309 * transform after it has processed the pixel successfully.
6310 */
6311 const struct image_transform *next;
6312
6313 /* A single transform for the image, expressed as a series of function
6314 * callbacks and some space for values.
6315 *
6316 * First a callback to add any required modifications to the png_modifier;
6317 * this gets called just before the modifier is set up for read.
6318 */
6319 void (*ini)(const struct image_transform *this,
6320 struct transform_display *that);
6321
6322 /* And a callback to set the transform on the current png_read_struct:
6323 */
6324 void (*set)(const struct image_transform *this,
6325 struct transform_display *that, png_structp pp, png_infop pi);
6326
6327 /* Then a transform that takes an input pixel in one PNG format or another
6328 * and modifies it by a pngvalid implementation of the transform (thus
6329 * duplicating the libpng intent without, we hope, duplicating the bugs
6330 * in the libpng implementation!) The png_structp is solely to allow error
6331 * reporting via png_error and png_warning.
6332 */
6333 void (*mod)(const struct image_transform *this, image_pixel *that,
6334 png_const_structp pp, const struct transform_display *display);
6335
6336 /* Add this transform to the list and return true if the transform is
6337 * meaningful for this colour type and bit depth - if false then the
6338 * transform should have no effect on the image so there's not a lot of
6339 * point running it.
6340 */
6341 int (*add)(struct image_transform *this,
6342 const struct image_transform **that, png_byte colour_type,
6343 png_byte bit_depth);
6344 } image_transform;
6345
6346 typedef struct transform_display
6347 {
6348 standard_display this;
6349
6350 /* Parameters */
6351 png_modifier* pm;
6352 const image_transform* transform_list;
6353 unsigned int max_gamma_8;
6354
6355 /* Local variables */
6356 png_byte output_colour_type;
6357 png_byte output_bit_depth;
6358 png_byte unpacked;
6359
6360 /* Modifications (not necessarily used.) */
6361 gama_modification gama_mod;
6362 chrm_modification chrm_mod;
6363 srgb_modification srgb_mod;
6364 } transform_display;
6365
6366 /* Set sRGB, cHRM and gAMA transforms as required by the current encoding. */
6367 static void
transform_set_encoding(transform_display * this)6368 transform_set_encoding(transform_display *this)
6369 {
6370 /* Set up the png_modifier '_current' fields then use these to determine how
6371 * to add appropriate chunks.
6372 */
6373 png_modifier *pm = this->pm;
6374
6375 modifier_set_encoding(pm);
6376
6377 if (modifier_color_encoding_is_set(pm))
6378 {
6379 if (modifier_color_encoding_is_sRGB(pm))
6380 srgb_modification_init(&this->srgb_mod, pm, PNG_sRGB_INTENT_ABSOLUTE);
6381
6382 else
6383 {
6384 /* Set gAMA and cHRM separately. */
6385 gama_modification_init(&this->gama_mod, pm, pm->current_gamma);
6386
6387 if (pm->current_encoding != 0)
6388 chrm_modification_init(&this->chrm_mod, pm, pm->current_encoding);
6389 }
6390 }
6391 }
6392
6393 /* Three functions to end the list: */
6394 static void
image_transform_ini_end(const image_transform * this,transform_display * that)6395 image_transform_ini_end(const image_transform *this,
6396 transform_display *that)
6397 {
6398 UNUSED(this)
6399 UNUSED(that)
6400 }
6401
6402 static void
image_transform_set_end(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)6403 image_transform_set_end(const image_transform *this,
6404 transform_display *that, png_structp pp, png_infop pi)
6405 {
6406 UNUSED(this)
6407 UNUSED(that)
6408 UNUSED(pp)
6409 UNUSED(pi)
6410 }
6411
6412 /* At the end of the list recalculate the output image pixel value from the
6413 * double precision values set up by the preceding 'mod' calls:
6414 */
6415 static unsigned int
sample_scale(double sample_value,unsigned int scale)6416 sample_scale(double sample_value, unsigned int scale)
6417 {
6418 sample_value = floor(sample_value * scale + .5);
6419
6420 /* Return NaN as 0: */
6421 if (!(sample_value > 0))
6422 sample_value = 0;
6423 else if (sample_value > scale)
6424 sample_value = scale;
6425
6426 return (unsigned int)sample_value;
6427 }
6428
6429 static void
image_transform_mod_end(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)6430 image_transform_mod_end(const image_transform *this, image_pixel *that,
6431 png_const_structp pp, const transform_display *display)
6432 {
6433 const unsigned int scale = (1U<<that->sample_depth)-1;
6434 const int sig_bits = that->sig_bits;
6435
6436 UNUSED(this)
6437 UNUSED(pp)
6438 UNUSED(display)
6439
6440 /* At the end recalculate the digitized red green and blue values according
6441 * to the current sample_depth of the pixel.
6442 *
6443 * The sample value is simply scaled to the maximum, checking for over
6444 * and underflow (which can both happen for some image transforms,
6445 * including simple size scaling, though libpng doesn't do that at present.
6446 */
6447 that->red = sample_scale(that->redf, scale);
6448
6449 /* This is a bit bogus; really the above calculation should use the red_sBIT
6450 * value, not sample_depth, but because libpng does png_set_shift by just
6451 * shifting the bits we get errors if we don't do it the same way.
6452 */
6453 if (sig_bits && that->red_sBIT < that->sample_depth)
6454 that->red >>= that->sample_depth - that->red_sBIT;
6455
6456 /* The error value is increased, at the end, according to the lowest sBIT
6457 * value seen. Common sense tells us that the intermediate integer
6458 * representations are no more accurate than +/- 0.5 in the integral values,
6459 * the sBIT allows the implementation to be worse than this. In addition the
6460 * PNG specification actually permits any error within the range (-1..+1),
6461 * but that is ignored here. Instead the final digitized value is compared,
6462 * below to the digitized value of the error limits - this has the net effect
6463 * of allowing (almost) +/-1 in the output value. It's difficult to see how
6464 * any algorithm that digitizes intermediate results can be more accurate.
6465 */
6466 that->rede += 1./(2*((1U<<that->red_sBIT)-1));
6467
6468 if (that->colour_type & PNG_COLOR_MASK_COLOR)
6469 {
6470 that->green = sample_scale(that->greenf, scale);
6471 if (sig_bits && that->green_sBIT < that->sample_depth)
6472 that->green >>= that->sample_depth - that->green_sBIT;
6473
6474 that->blue = sample_scale(that->bluef, scale);
6475 if (sig_bits && that->blue_sBIT < that->sample_depth)
6476 that->blue >>= that->sample_depth - that->blue_sBIT;
6477
6478 that->greene += 1./(2*((1U<<that->green_sBIT)-1));
6479 that->bluee += 1./(2*((1U<<that->blue_sBIT)-1));
6480 }
6481 else
6482 {
6483 that->blue = that->green = that->red;
6484 that->bluef = that->greenf = that->redf;
6485 that->bluee = that->greene = that->rede;
6486 }
6487
6488 if ((that->colour_type & PNG_COLOR_MASK_ALPHA) ||
6489 that->colour_type == PNG_COLOR_TYPE_PALETTE)
6490 {
6491 that->alpha = sample_scale(that->alphaf, scale);
6492 that->alphae += 1./(2*((1U<<that->alpha_sBIT)-1));
6493 }
6494 else
6495 {
6496 that->alpha = scale; /* opaque */
6497 that->alphaf = 1; /* Override this. */
6498 that->alphae = 0; /* It's exact ;-) */
6499 }
6500
6501 if (sig_bits && that->alpha_sBIT < that->sample_depth)
6502 that->alpha >>= that->sample_depth - that->alpha_sBIT;
6503 }
6504
6505 /* Static 'end' structure: */
6506 static image_transform image_transform_end =
6507 {
6508 "(end)", /* name */
6509 1, /* enable */
6510 0, /* list */
6511 0, /* global_use */
6512 0, /* local_use */
6513 0, /* next */
6514 image_transform_ini_end,
6515 image_transform_set_end,
6516 image_transform_mod_end,
6517 0 /* never called, I want it to crash if it is! */
6518 };
6519
6520 /* Reader callbacks and implementations, where they differ from the standard
6521 * ones.
6522 */
6523 static void
transform_display_init(transform_display * dp,png_modifier * pm,png_uint_32 id,const image_transform * transform_list)6524 transform_display_init(transform_display *dp, png_modifier *pm, png_uint_32 id,
6525 const image_transform *transform_list)
6526 {
6527 memset(dp, 0, sizeof *dp);
6528
6529 /* Standard fields */
6530 standard_display_init(&dp->this, &pm->this, id, do_read_interlace,
6531 pm->use_update_info);
6532
6533 /* Parameter fields */
6534 dp->pm = pm;
6535 dp->transform_list = transform_list;
6536 dp->max_gamma_8 = 16;
6537
6538 /* Local variable fields */
6539 dp->output_colour_type = 255; /* invalid */
6540 dp->output_bit_depth = 255; /* invalid */
6541 dp->unpacked = 0; /* not unpacked */
6542 }
6543
6544 static void
transform_info_imp(transform_display * dp,png_structp pp,png_infop pi)6545 transform_info_imp(transform_display *dp, png_structp pp, png_infop pi)
6546 {
6547 /* Reuse the standard stuff as appropriate. */
6548 standard_info_part1(&dp->this, pp, pi);
6549
6550 /* Now set the list of transforms. */
6551 dp->transform_list->set(dp->transform_list, dp, pp, pi);
6552
6553 /* Update the info structure for these transforms: */
6554 {
6555 int i = dp->this.use_update_info;
6556 /* Always do one call, even if use_update_info is 0. */
6557 do
6558 png_read_update_info(pp, pi);
6559 while (--i > 0);
6560 }
6561
6562 /* And get the output information into the standard_display */
6563 standard_info_part2(&dp->this, pp, pi, 1/*images*/);
6564
6565 /* Plus the extra stuff we need for the transform tests: */
6566 dp->output_colour_type = png_get_color_type(pp, pi);
6567 dp->output_bit_depth = png_get_bit_depth(pp, pi);
6568
6569 /* If png_set_filler is in action then fake the output color type to include
6570 * an alpha channel where appropriate.
6571 */
6572 if (dp->output_bit_depth >= 8 &&
6573 (dp->output_colour_type == PNG_COLOR_TYPE_RGB ||
6574 dp->output_colour_type == PNG_COLOR_TYPE_GRAY) && dp->this.filler)
6575 dp->output_colour_type |= 4;
6576
6577 /* Validate the combination of colour type and bit depth that we are getting
6578 * out of libpng; the semantics of something not in the PNG spec are, at
6579 * best, unclear.
6580 */
6581 switch (dp->output_colour_type)
6582 {
6583 case PNG_COLOR_TYPE_PALETTE:
6584 if (dp->output_bit_depth > 8) goto error;
6585 /*FALL THROUGH*/
6586 case PNG_COLOR_TYPE_GRAY:
6587 if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 ||
6588 dp->output_bit_depth == 4)
6589 break;
6590 /*FALL THROUGH*/
6591 default:
6592 if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16)
6593 break;
6594 /*FALL THROUGH*/
6595 error:
6596 {
6597 char message[128];
6598 size_t pos;
6599
6600 pos = safecat(message, sizeof message, 0,
6601 "invalid final bit depth: colour type(");
6602 pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
6603 pos = safecat(message, sizeof message, pos, ") with bit depth: ");
6604 pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
6605
6606 png_error(pp, message);
6607 }
6608 }
6609
6610 /* Use a test pixel to check that the output agrees with what we expect -
6611 * this avoids running the whole test if the output is unexpected. This also
6612 * checks for internal errors.
6613 */
6614 {
6615 image_pixel test_pixel;
6616
6617 memset(&test_pixel, 0, sizeof test_pixel);
6618 test_pixel.colour_type = dp->this.colour_type; /* input */
6619 test_pixel.bit_depth = dp->this.bit_depth;
6620 if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
6621 test_pixel.sample_depth = 8;
6622 else
6623 test_pixel.sample_depth = test_pixel.bit_depth;
6624 /* Don't need sBIT here, but it must be set to non-zero to avoid
6625 * arithmetic overflows.
6626 */
6627 test_pixel.have_tRNS = dp->this.is_transparent != 0;
6628 test_pixel.red_sBIT = test_pixel.green_sBIT = test_pixel.blue_sBIT =
6629 test_pixel.alpha_sBIT = test_pixel.sample_depth;
6630
6631 dp->transform_list->mod(dp->transform_list, &test_pixel, pp, dp);
6632
6633 if (test_pixel.colour_type != dp->output_colour_type)
6634 {
6635 char message[128];
6636 size_t pos = safecat(message, sizeof message, 0, "colour type ");
6637
6638 pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
6639 pos = safecat(message, sizeof message, pos, " expected ");
6640 pos = safecatn(message, sizeof message, pos, test_pixel.colour_type);
6641
6642 png_error(pp, message);
6643 }
6644
6645 if (test_pixel.bit_depth != dp->output_bit_depth)
6646 {
6647 char message[128];
6648 size_t pos = safecat(message, sizeof message, 0, "bit depth ");
6649
6650 pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
6651 pos = safecat(message, sizeof message, pos, " expected ");
6652 pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
6653
6654 png_error(pp, message);
6655 }
6656
6657 /* If both bit depth and colour type are correct check the sample depth.
6658 */
6659 if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE &&
6660 test_pixel.sample_depth != 8) /* oops - internal error! */
6661 png_error(pp, "pngvalid: internal: palette sample depth not 8");
6662 else if (dp->unpacked && test_pixel.bit_depth != 8)
6663 png_error(pp, "pngvalid: internal: bad unpacked pixel depth");
6664 else if (!dp->unpacked && test_pixel.colour_type != PNG_COLOR_TYPE_PALETTE
6665 && test_pixel.bit_depth != test_pixel.sample_depth)
6666 {
6667 char message[128];
6668 size_t pos = safecat(message, sizeof message, 0,
6669 "internal: sample depth ");
6670
6671 /* Because unless something has set 'unpacked' or the image is palette
6672 * mapped we expect the transform to keep sample depth and bit depth
6673 * the same.
6674 */
6675 pos = safecatn(message, sizeof message, pos, test_pixel.sample_depth);
6676 pos = safecat(message, sizeof message, pos, " expected ");
6677 pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
6678
6679 png_error(pp, message);
6680 }
6681 else if (test_pixel.bit_depth != dp->output_bit_depth)
6682 {
6683 /* This could be a libpng error too; libpng has not produced what we
6684 * expect for the output bit depth.
6685 */
6686 char message[128];
6687 size_t pos = safecat(message, sizeof message, 0,
6688 "internal: bit depth ");
6689
6690 pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
6691 pos = safecat(message, sizeof message, pos, " expected ");
6692 pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
6693
6694 png_error(pp, message);
6695 }
6696 }
6697 }
6698
6699 static void PNGCBAPI
transform_info(png_structp pp,png_infop pi)6700 transform_info(png_structp pp, png_infop pi)
6701 {
6702 transform_info_imp(voidcast(transform_display*, png_get_progressive_ptr(pp)),
6703 pp, pi);
6704 }
6705
6706 static void
transform_range_check(png_const_structp pp,unsigned int r,unsigned int g,unsigned int b,unsigned int a,unsigned int in_digitized,double in,unsigned int out,png_byte sample_depth,double err,double limit,const char * name,double digitization_error)6707 transform_range_check(png_const_structp pp, unsigned int r, unsigned int g,
6708 unsigned int b, unsigned int a, unsigned int in_digitized, double in,
6709 unsigned int out, png_byte sample_depth, double err, double limit,
6710 const char *name, double digitization_error)
6711 {
6712 /* Compare the scaled, digitzed, values of our local calculation (in+-err)
6713 * with the digitized values libpng produced; 'sample_depth' is the actual
6714 * digitization depth of the libpng output colors (the bit depth except for
6715 * palette images where it is always 8.) The check on 'err' is to detect
6716 * internal errors in pngvalid itself.
6717 */
6718 unsigned int max = (1U<<sample_depth)-1;
6719 double in_min = ceil((in-err)*max - digitization_error);
6720 double in_max = floor((in+err)*max + digitization_error);
6721 if (debugonly(err > limit ||) !(out >= in_min && out <= in_max))
6722 {
6723 char message[256];
6724 size_t pos;
6725
6726 pos = safecat(message, sizeof message, 0, name);
6727 pos = safecat(message, sizeof message, pos, " output value error: rgba(");
6728 pos = safecatn(message, sizeof message, pos, r);
6729 pos = safecat(message, sizeof message, pos, ",");
6730 pos = safecatn(message, sizeof message, pos, g);
6731 pos = safecat(message, sizeof message, pos, ",");
6732 pos = safecatn(message, sizeof message, pos, b);
6733 pos = safecat(message, sizeof message, pos, ",");
6734 pos = safecatn(message, sizeof message, pos, a);
6735 pos = safecat(message, sizeof message, pos, "): ");
6736 pos = safecatn(message, sizeof message, pos, out);
6737 pos = safecat(message, sizeof message, pos, " expected: ");
6738 pos = safecatn(message, sizeof message, pos, in_digitized);
6739 pos = safecat(message, sizeof message, pos, " (");
6740 pos = safecatd(message, sizeof message, pos, (in-err)*max, 3);
6741 pos = safecat(message, sizeof message, pos, "..");
6742 pos = safecatd(message, sizeof message, pos, (in+err)*max, 3);
6743 pos = safecat(message, sizeof message, pos, ")");
6744
6745 png_error(pp, message);
6746 }
6747
6748 UNUSED(limit)
6749 }
6750
6751 static void
transform_image_validate(transform_display * dp,png_const_structp pp,png_infop pi)6752 transform_image_validate(transform_display *dp, png_const_structp pp,
6753 png_infop pi)
6754 {
6755 /* Constants for the loop below: */
6756 const png_store* const ps = dp->this.ps;
6757 const png_byte in_ct = dp->this.colour_type;
6758 const png_byte in_bd = dp->this.bit_depth;
6759 const png_uint_32 w = dp->this.w;
6760 const png_uint_32 h = dp->this.h;
6761 const png_byte out_ct = dp->output_colour_type;
6762 const png_byte out_bd = dp->output_bit_depth;
6763 const png_byte sample_depth = (png_byte)(out_ct ==
6764 PNG_COLOR_TYPE_PALETTE ? 8 : out_bd);
6765 const png_byte red_sBIT = dp->this.red_sBIT;
6766 const png_byte green_sBIT = dp->this.green_sBIT;
6767 const png_byte blue_sBIT = dp->this.blue_sBIT;
6768 const png_byte alpha_sBIT = dp->this.alpha_sBIT;
6769 const int have_tRNS = dp->this.is_transparent;
6770 double digitization_error;
6771
6772 store_palette out_palette;
6773 png_uint_32 y;
6774
6775 UNUSED(pi)
6776
6777 /* Check for row overwrite errors */
6778 store_image_check(dp->this.ps, pp, 0);
6779
6780 /* Read the palette corresponding to the output if the output colour type
6781 * indicates a palette, othewise set out_palette to garbage.
6782 */
6783 if (out_ct == PNG_COLOR_TYPE_PALETTE)
6784 {
6785 /* Validate that the palette count itself has not changed - this is not
6786 * expected.
6787 */
6788 int npalette = (-1);
6789
6790 (void)read_palette(out_palette, &npalette, pp, pi);
6791 if (npalette != dp->this.npalette)
6792 png_error(pp, "unexpected change in palette size");
6793
6794 digitization_error = .5;
6795 }
6796 else
6797 {
6798 png_byte in_sample_depth;
6799
6800 memset(out_palette, 0x5e, sizeof out_palette);
6801
6802 /* use-input-precision means assume that if the input has 8 bit (or less)
6803 * samples and the output has 16 bit samples the calculations will be done
6804 * with 8 bit precision, not 16.
6805 */
6806 if (in_ct == PNG_COLOR_TYPE_PALETTE || in_bd < 16)
6807 in_sample_depth = 8;
6808 else
6809 in_sample_depth = in_bd;
6810
6811 if (sample_depth != 16 || in_sample_depth > 8 ||
6812 !dp->pm->calculations_use_input_precision)
6813 digitization_error = .5;
6814
6815 /* Else calculations are at 8 bit precision, and the output actually
6816 * consists of scaled 8-bit values, so scale .5 in 8 bits to the 16 bits:
6817 */
6818 else
6819 digitization_error = .5 * 257;
6820 }
6821
6822 for (y=0; y<h; ++y)
6823 {
6824 png_const_bytep const pRow = store_image_row(ps, pp, 0, y);
6825 png_uint_32 x;
6826
6827 /* The original, standard, row pre-transforms. */
6828 png_byte std[STANDARD_ROWMAX];
6829
6830 transform_row(pp, std, in_ct, in_bd, y);
6831
6832 /* Go through each original pixel transforming it and comparing with what
6833 * libpng did to the same pixel.
6834 */
6835 for (x=0; x<w; ++x)
6836 {
6837 image_pixel in_pixel, out_pixel;
6838 unsigned int r, g, b, a;
6839
6840 /* Find out what we think the pixel should be: */
6841 image_pixel_init(&in_pixel, std, in_ct, in_bd, x, dp->this.palette,
6842 NULL);
6843
6844 in_pixel.red_sBIT = red_sBIT;
6845 in_pixel.green_sBIT = green_sBIT;
6846 in_pixel.blue_sBIT = blue_sBIT;
6847 in_pixel.alpha_sBIT = alpha_sBIT;
6848 in_pixel.have_tRNS = have_tRNS != 0;
6849
6850 /* For error detection, below. */
6851 r = in_pixel.red;
6852 g = in_pixel.green;
6853 b = in_pixel.blue;
6854 a = in_pixel.alpha;
6855
6856 /* This applies the transforms to the input data, including output
6857 * format operations which must be used when reading the output
6858 * pixel that libpng produces.
6859 */
6860 dp->transform_list->mod(dp->transform_list, &in_pixel, pp, dp);
6861
6862 /* Read the output pixel and compare it to what we got, we don't
6863 * use the error field here, so no need to update sBIT. in_pixel
6864 * says whether we expect libpng to change the output format.
6865 */
6866 image_pixel_init(&out_pixel, pRow, out_ct, out_bd, x, out_palette,
6867 &in_pixel);
6868
6869 /* We don't expect changes to the index here even if the bit depth is
6870 * changed.
6871 */
6872 if (in_ct == PNG_COLOR_TYPE_PALETTE &&
6873 out_ct == PNG_COLOR_TYPE_PALETTE)
6874 {
6875 if (in_pixel.palette_index != out_pixel.palette_index)
6876 png_error(pp, "unexpected transformed palette index");
6877 }
6878
6879 /* Check the colours for palette images too - in fact the palette could
6880 * be separately verified itself in most cases.
6881 */
6882 if (in_pixel.red != out_pixel.red)
6883 transform_range_check(pp, r, g, b, a, in_pixel.red, in_pixel.redf,
6884 out_pixel.red, sample_depth, in_pixel.rede,
6885 dp->pm->limit + 1./(2*((1U<<in_pixel.red_sBIT)-1)), "red/gray",
6886 digitization_error);
6887
6888 if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
6889 in_pixel.green != out_pixel.green)
6890 transform_range_check(pp, r, g, b, a, in_pixel.green,
6891 in_pixel.greenf, out_pixel.green, sample_depth, in_pixel.greene,
6892 dp->pm->limit + 1./(2*((1U<<in_pixel.green_sBIT)-1)), "green",
6893 digitization_error);
6894
6895 if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
6896 in_pixel.blue != out_pixel.blue)
6897 transform_range_check(pp, r, g, b, a, in_pixel.blue, in_pixel.bluef,
6898 out_pixel.blue, sample_depth, in_pixel.bluee,
6899 dp->pm->limit + 1./(2*((1U<<in_pixel.blue_sBIT)-1)), "blue",
6900 digitization_error);
6901
6902 if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0 &&
6903 in_pixel.alpha != out_pixel.alpha)
6904 transform_range_check(pp, r, g, b, a, in_pixel.alpha,
6905 in_pixel.alphaf, out_pixel.alpha, sample_depth, in_pixel.alphae,
6906 dp->pm->limit + 1./(2*((1U<<in_pixel.alpha_sBIT)-1)), "alpha",
6907 digitization_error);
6908 } /* pixel (x) loop */
6909 } /* row (y) loop */
6910
6911 /* Record that something was actually checked to avoid a false positive. */
6912 dp->this.ps->validated = 1;
6913 }
6914
6915 static void PNGCBAPI
transform_end(png_structp ppIn,png_infop pi)6916 transform_end(png_structp ppIn, png_infop pi)
6917 {
6918 png_const_structp pp = ppIn;
6919 transform_display *dp = voidcast(transform_display*,
6920 png_get_progressive_ptr(pp));
6921
6922 if (!dp->this.speed)
6923 transform_image_validate(dp, pp, pi);
6924 else
6925 dp->this.ps->validated = 1;
6926 }
6927
6928 /* A single test run. */
6929 static void
transform_test(png_modifier * pmIn,const png_uint_32 idIn,const image_transform * transform_listIn,const char * const name)6930 transform_test(png_modifier *pmIn, const png_uint_32 idIn,
6931 const image_transform* transform_listIn, const char * const name)
6932 {
6933 transform_display d;
6934 context(&pmIn->this, fault);
6935
6936 transform_display_init(&d, pmIn, idIn, transform_listIn);
6937
6938 Try
6939 {
6940 size_t pos = 0;
6941 png_structp pp;
6942 png_infop pi;
6943 char full_name[256];
6944
6945 /* Make sure the encoding fields are correct and enter the required
6946 * modifications.
6947 */
6948 transform_set_encoding(&d);
6949
6950 /* Add any modifications required by the transform list. */
6951 d.transform_list->ini(d.transform_list, &d);
6952
6953 /* Add the color space information, if any, to the name. */
6954 pos = safecat(full_name, sizeof full_name, pos, name);
6955 pos = safecat_current_encoding(full_name, sizeof full_name, pos, d.pm);
6956
6957 /* Get a png_struct for reading the image. */
6958 pp = set_modifier_for_read(d.pm, &pi, d.this.id, full_name);
6959 standard_palette_init(&d.this);
6960
6961 # if 0
6962 /* Logging (debugging only) */
6963 {
6964 char buffer[256];
6965
6966 (void)store_message(&d.pm->this, pp, buffer, sizeof buffer, 0,
6967 "running test");
6968
6969 fprintf(stderr, "%s\n", buffer);
6970 }
6971 # endif
6972
6973 /* Introduce the correct read function. */
6974 if (d.pm->this.progressive)
6975 {
6976 /* Share the row function with the standard implementation. */
6977 png_set_progressive_read_fn(pp, &d, transform_info, progressive_row,
6978 transform_end);
6979
6980 /* Now feed data into the reader until we reach the end: */
6981 modifier_progressive_read(d.pm, pp, pi);
6982 }
6983 else
6984 {
6985 /* modifier_read expects a png_modifier* */
6986 png_set_read_fn(pp, d.pm, modifier_read);
6987
6988 /* Check the header values: */
6989 png_read_info(pp, pi);
6990
6991 /* Process the 'info' requirements. Only one image is generated */
6992 transform_info_imp(&d, pp, pi);
6993
6994 sequential_row(&d.this, pp, pi, -1, 0);
6995
6996 if (!d.this.speed)
6997 transform_image_validate(&d, pp, pi);
6998 else
6999 d.this.ps->validated = 1;
7000 }
7001
7002 modifier_reset(d.pm);
7003 }
7004
7005 Catch(fault)
7006 {
7007 modifier_reset(voidcast(png_modifier*,(void*)fault));
7008 }
7009 }
7010
7011 /* The transforms: */
7012 #define ITSTRUCT(name) image_transform_##name
7013 #define ITDATA(name) image_transform_data_##name
7014 #define image_transform_ini image_transform_default_ini
7015 #define IT(name)\
7016 static image_transform ITSTRUCT(name) =\
7017 {\
7018 #name,\
7019 1, /*enable*/\
7020 &PT, /*list*/\
7021 0, /*global_use*/\
7022 0, /*local_use*/\
7023 0, /*next*/\
7024 image_transform_ini,\
7025 image_transform_png_set_##name##_set,\
7026 image_transform_png_set_##name##_mod,\
7027 image_transform_png_set_##name##_add\
7028 }
7029 #define PT ITSTRUCT(end) /* stores the previous transform */
7030
7031 /* To save code: */
7032 extern void image_transform_default_ini(const image_transform *this,
7033 transform_display *that); /* silence GCC warnings */
7034
7035 void /* private, but almost always needed */
image_transform_default_ini(const image_transform * this,transform_display * that)7036 image_transform_default_ini(const image_transform *this,
7037 transform_display *that)
7038 {
7039 this->next->ini(this->next, that);
7040 }
7041
7042 #ifdef PNG_READ_BACKGROUND_SUPPORTED
7043 static int
image_transform_default_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)7044 image_transform_default_add(image_transform *this,
7045 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7046 {
7047 UNUSED(colour_type)
7048 UNUSED(bit_depth)
7049
7050 this->next = *that;
7051 *that = this;
7052
7053 return 1;
7054 }
7055 #endif
7056
7057 #ifdef PNG_READ_EXPAND_SUPPORTED
7058 /* png_set_palette_to_rgb */
7059 static void
image_transform_png_set_palette_to_rgb_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)7060 image_transform_png_set_palette_to_rgb_set(const image_transform *this,
7061 transform_display *that, png_structp pp, png_infop pi)
7062 {
7063 png_set_palette_to_rgb(pp);
7064 this->next->set(this->next, that, pp, pi);
7065 }
7066
7067 static void
image_transform_png_set_palette_to_rgb_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)7068 image_transform_png_set_palette_to_rgb_mod(const image_transform *this,
7069 image_pixel *that, png_const_structp pp,
7070 const transform_display *display)
7071 {
7072 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7073 image_pixel_convert_PLTE(that);
7074
7075 this->next->mod(this->next, that, pp, display);
7076 }
7077
7078 static int
image_transform_png_set_palette_to_rgb_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)7079 image_transform_png_set_palette_to_rgb_add(image_transform *this,
7080 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7081 {
7082 UNUSED(bit_depth)
7083
7084 this->next = *that;
7085 *that = this;
7086
7087 return colour_type == PNG_COLOR_TYPE_PALETTE;
7088 }
7089
7090 IT(palette_to_rgb);
7091 #undef PT
7092 #define PT ITSTRUCT(palette_to_rgb)
7093 #endif /* PNG_READ_EXPAND_SUPPORTED */
7094
7095 #ifdef PNG_READ_EXPAND_SUPPORTED
7096 /* png_set_tRNS_to_alpha */
7097 static void
image_transform_png_set_tRNS_to_alpha_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)7098 image_transform_png_set_tRNS_to_alpha_set(const image_transform *this,
7099 transform_display *that, png_structp pp, png_infop pi)
7100 {
7101 png_set_tRNS_to_alpha(pp);
7102
7103 /* If there was a tRNS chunk that would get expanded and add an alpha
7104 * channel is_transparent must be updated:
7105 */
7106 if (that->this.has_tRNS)
7107 that->this.is_transparent = 1;
7108
7109 this->next->set(this->next, that, pp, pi);
7110 }
7111
7112 static void
image_transform_png_set_tRNS_to_alpha_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)7113 image_transform_png_set_tRNS_to_alpha_mod(const image_transform *this,
7114 image_pixel *that, png_const_structp pp,
7115 const transform_display *display)
7116 {
7117 #if PNG_LIBPNG_VER < 10700
7118 /* LIBPNG BUG: this always forces palette images to RGB. */
7119 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7120 image_pixel_convert_PLTE(that);
7121 #endif
7122
7123 /* This effectively does an 'expand' only if there is some transparency to
7124 * convert to an alpha channel.
7125 */
7126 if (that->have_tRNS)
7127 # if PNG_LIBPNG_VER >= 10700
7128 if (that->colour_type != PNG_COLOR_TYPE_PALETTE &&
7129 (that->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
7130 # endif
7131 image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
7132
7133 #if PNG_LIBPNG_VER < 10700
7134 /* LIBPNG BUG: otherwise libpng still expands to 8 bits! */
7135 else
7136 {
7137 if (that->bit_depth < 8)
7138 that->bit_depth =8;
7139 if (that->sample_depth < 8)
7140 that->sample_depth = 8;
7141 }
7142 #endif
7143
7144 this->next->mod(this->next, that, pp, display);
7145 }
7146
7147 static int
image_transform_png_set_tRNS_to_alpha_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)7148 image_transform_png_set_tRNS_to_alpha_add(image_transform *this,
7149 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7150 {
7151 UNUSED(bit_depth)
7152
7153 this->next = *that;
7154 *that = this;
7155
7156 /* We don't know yet whether there will be a tRNS chunk, but we know that
7157 * this transformation should do nothing if there already is an alpha
7158 * channel. In addition, after the bug fix in 1.7.0, there is no longer
7159 * any action on a palette image.
7160 */
7161 return
7162 # if PNG_LIBPNG_VER >= 10700
7163 colour_type != PNG_COLOR_TYPE_PALETTE &&
7164 # endif
7165 (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
7166 }
7167
7168 IT(tRNS_to_alpha);
7169 #undef PT
7170 #define PT ITSTRUCT(tRNS_to_alpha)
7171 #endif /* PNG_READ_EXPAND_SUPPORTED */
7172
7173 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
7174 /* png_set_gray_to_rgb */
7175 static void
image_transform_png_set_gray_to_rgb_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)7176 image_transform_png_set_gray_to_rgb_set(const image_transform *this,
7177 transform_display *that, png_structp pp, png_infop pi)
7178 {
7179 png_set_gray_to_rgb(pp);
7180 /* NOTE: this doesn't result in tRNS expansion. */
7181 this->next->set(this->next, that, pp, pi);
7182 }
7183
7184 static void
image_transform_png_set_gray_to_rgb_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)7185 image_transform_png_set_gray_to_rgb_mod(const image_transform *this,
7186 image_pixel *that, png_const_structp pp,
7187 const transform_display *display)
7188 {
7189 /* NOTE: we can actually pend the tRNS processing at this point because we
7190 * can correctly recognize the original pixel value even though we have
7191 * mapped the one gray channel to the three RGB ones, but in fact libpng
7192 * doesn't do this, so we don't either.
7193 */
7194 if ((that->colour_type & PNG_COLOR_MASK_COLOR) == 0 && that->have_tRNS)
7195 image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
7196
7197 /* Simply expand the bit depth and alter the colour type as required. */
7198 if (that->colour_type == PNG_COLOR_TYPE_GRAY)
7199 {
7200 /* RGB images have a bit depth at least equal to '8' */
7201 if (that->bit_depth < 8)
7202 that->sample_depth = that->bit_depth = 8;
7203
7204 /* And just changing the colour type works here because the green and blue
7205 * channels are being maintained in lock-step with the red/gray:
7206 */
7207 that->colour_type = PNG_COLOR_TYPE_RGB;
7208 }
7209
7210 else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
7211 that->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
7212
7213 this->next->mod(this->next, that, pp, display);
7214 }
7215
7216 static int
image_transform_png_set_gray_to_rgb_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)7217 image_transform_png_set_gray_to_rgb_add(image_transform *this,
7218 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7219 {
7220 UNUSED(bit_depth)
7221
7222 this->next = *that;
7223 *that = this;
7224
7225 return (colour_type & PNG_COLOR_MASK_COLOR) == 0;
7226 }
7227
7228 IT(gray_to_rgb);
7229 #undef PT
7230 #define PT ITSTRUCT(gray_to_rgb)
7231 #endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED */
7232
7233 #ifdef PNG_READ_EXPAND_SUPPORTED
7234 /* png_set_expand */
7235 static void
image_transform_png_set_expand_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)7236 image_transform_png_set_expand_set(const image_transform *this,
7237 transform_display *that, png_structp pp, png_infop pi)
7238 {
7239 png_set_expand(pp);
7240
7241 if (that->this.has_tRNS)
7242 that->this.is_transparent = 1;
7243
7244 this->next->set(this->next, that, pp, pi);
7245 }
7246
7247 static void
image_transform_png_set_expand_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)7248 image_transform_png_set_expand_mod(const image_transform *this,
7249 image_pixel *that, png_const_structp pp,
7250 const transform_display *display)
7251 {
7252 /* The general expand case depends on what the colour type is: */
7253 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7254 image_pixel_convert_PLTE(that);
7255 else if (that->bit_depth < 8) /* grayscale */
7256 that->sample_depth = that->bit_depth = 8;
7257
7258 if (that->have_tRNS)
7259 image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
7260
7261 this->next->mod(this->next, that, pp, display);
7262 }
7263
7264 static int
image_transform_png_set_expand_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)7265 image_transform_png_set_expand_add(image_transform *this,
7266 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7267 {
7268 UNUSED(bit_depth)
7269
7270 this->next = *that;
7271 *that = this;
7272
7273 /* 'expand' should do nothing for RGBA or GA input - no tRNS and the bit
7274 * depth is at least 8 already.
7275 */
7276 return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
7277 }
7278
7279 IT(expand);
7280 #undef PT
7281 #define PT ITSTRUCT(expand)
7282 #endif /* PNG_READ_EXPAND_SUPPORTED */
7283
7284 #ifdef PNG_READ_EXPAND_SUPPORTED
7285 /* png_set_expand_gray_1_2_4_to_8
7286 * Pre 1.7.0 LIBPNG BUG: this just does an 'expand'
7287 */
7288 static void
image_transform_png_set_expand_gray_1_2_4_to_8_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)7289 image_transform_png_set_expand_gray_1_2_4_to_8_set(
7290 const image_transform *this, transform_display *that, png_structp pp,
7291 png_infop pi)
7292 {
7293 png_set_expand_gray_1_2_4_to_8(pp);
7294 /* NOTE: don't expect this to expand tRNS */
7295 this->next->set(this->next, that, pp, pi);
7296 }
7297
7298 static void
image_transform_png_set_expand_gray_1_2_4_to_8_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)7299 image_transform_png_set_expand_gray_1_2_4_to_8_mod(
7300 const image_transform *this, image_pixel *that, png_const_structp pp,
7301 const transform_display *display)
7302 {
7303 #if PNG_LIBPNG_VER < 10700
7304 image_transform_png_set_expand_mod(this, that, pp, display);
7305 #else
7306 /* Only expand grayscale of bit depth less than 8: */
7307 if (that->colour_type == PNG_COLOR_TYPE_GRAY &&
7308 that->bit_depth < 8)
7309 that->sample_depth = that->bit_depth = 8;
7310
7311 this->next->mod(this->next, that, pp, display);
7312 #endif /* 1.7 or later */
7313 }
7314
7315 static int
image_transform_png_set_expand_gray_1_2_4_to_8_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)7316 image_transform_png_set_expand_gray_1_2_4_to_8_add(image_transform *this,
7317 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7318 {
7319 #if PNG_LIBPNG_VER < 10700
7320 return image_transform_png_set_expand_add(this, that, colour_type,
7321 bit_depth);
7322 #else
7323 UNUSED(bit_depth)
7324
7325 this->next = *that;
7326 *that = this;
7327
7328 /* This should do nothing unless the color type is gray and the bit depth is
7329 * less than 8:
7330 */
7331 return colour_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8;
7332 #endif /* 1.7 or later */
7333 }
7334
7335 IT(expand_gray_1_2_4_to_8);
7336 #undef PT
7337 #define PT ITSTRUCT(expand_gray_1_2_4_to_8)
7338 #endif /* PNG_READ_EXPAND_SUPPORTED */
7339
7340 #ifdef PNG_READ_EXPAND_16_SUPPORTED
7341 /* png_set_expand_16 */
7342 static void
image_transform_png_set_expand_16_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)7343 image_transform_png_set_expand_16_set(const image_transform *this,
7344 transform_display *that, png_structp pp, png_infop pi)
7345 {
7346 png_set_expand_16(pp);
7347
7348 /* NOTE: prior to 1.7 libpng does SET_EXPAND as well, so tRNS is expanded. */
7349 # if PNG_LIBPNG_VER < 10700
7350 if (that->this.has_tRNS)
7351 that->this.is_transparent = 1;
7352 # endif
7353
7354 this->next->set(this->next, that, pp, pi);
7355 }
7356
7357 static void
image_transform_png_set_expand_16_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)7358 image_transform_png_set_expand_16_mod(const image_transform *this,
7359 image_pixel *that, png_const_structp pp,
7360 const transform_display *display)
7361 {
7362 /* Expect expand_16 to expand everything to 16 bits as a result of also
7363 * causing 'expand' to happen.
7364 */
7365 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7366 image_pixel_convert_PLTE(that);
7367
7368 if (that->have_tRNS)
7369 image_pixel_add_alpha(that, &display->this, 0/*!for background*/);
7370
7371 if (that->bit_depth < 16)
7372 that->sample_depth = that->bit_depth = 16;
7373
7374 this->next->mod(this->next, that, pp, display);
7375 }
7376
7377 static int
image_transform_png_set_expand_16_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)7378 image_transform_png_set_expand_16_add(image_transform *this,
7379 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7380 {
7381 UNUSED(colour_type)
7382
7383 this->next = *that;
7384 *that = this;
7385
7386 /* expand_16 does something unless the bit depth is already 16. */
7387 return bit_depth < 16;
7388 }
7389
7390 IT(expand_16);
7391 #undef PT
7392 #define PT ITSTRUCT(expand_16)
7393 #endif /* PNG_READ_EXPAND_16_SUPPORTED */
7394
7395 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED /* API added in 1.5.4 */
7396 /* png_set_scale_16 */
7397 static void
image_transform_png_set_scale_16_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)7398 image_transform_png_set_scale_16_set(const image_transform *this,
7399 transform_display *that, png_structp pp, png_infop pi)
7400 {
7401 png_set_scale_16(pp);
7402 # if PNG_LIBPNG_VER < 10700
7403 /* libpng will limit the gamma table size: */
7404 that->max_gamma_8 = PNG_MAX_GAMMA_8;
7405 # endif
7406 this->next->set(this->next, that, pp, pi);
7407 }
7408
7409 static void
image_transform_png_set_scale_16_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)7410 image_transform_png_set_scale_16_mod(const image_transform *this,
7411 image_pixel *that, png_const_structp pp,
7412 const transform_display *display)
7413 {
7414 if (that->bit_depth == 16)
7415 {
7416 that->sample_depth = that->bit_depth = 8;
7417 if (that->red_sBIT > 8) that->red_sBIT = 8;
7418 if (that->green_sBIT > 8) that->green_sBIT = 8;
7419 if (that->blue_sBIT > 8) that->blue_sBIT = 8;
7420 if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
7421 }
7422
7423 this->next->mod(this->next, that, pp, display);
7424 }
7425
7426 static int
image_transform_png_set_scale_16_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)7427 image_transform_png_set_scale_16_add(image_transform *this,
7428 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7429 {
7430 UNUSED(colour_type)
7431
7432 this->next = *that;
7433 *that = this;
7434
7435 return bit_depth > 8;
7436 }
7437
7438 IT(scale_16);
7439 #undef PT
7440 #define PT ITSTRUCT(scale_16)
7441 #endif /* PNG_READ_SCALE_16_TO_8_SUPPORTED (1.5.4 on) */
7442
7443 #ifdef PNG_READ_16_TO_8_SUPPORTED /* the default before 1.5.4 */
7444 /* png_set_strip_16 */
7445 static void
image_transform_png_set_strip_16_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)7446 image_transform_png_set_strip_16_set(const image_transform *this,
7447 transform_display *that, png_structp pp, png_infop pi)
7448 {
7449 png_set_strip_16(pp);
7450 # if PNG_LIBPNG_VER < 10700
7451 /* libpng will limit the gamma table size: */
7452 that->max_gamma_8 = PNG_MAX_GAMMA_8;
7453 # endif
7454 this->next->set(this->next, that, pp, pi);
7455 }
7456
7457 static void
image_transform_png_set_strip_16_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)7458 image_transform_png_set_strip_16_mod(const image_transform *this,
7459 image_pixel *that, png_const_structp pp,
7460 const transform_display *display)
7461 {
7462 if (that->bit_depth == 16)
7463 {
7464 that->sample_depth = that->bit_depth = 8;
7465 if (that->red_sBIT > 8) that->red_sBIT = 8;
7466 if (that->green_sBIT > 8) that->green_sBIT = 8;
7467 if (that->blue_sBIT > 8) that->blue_sBIT = 8;
7468 if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
7469
7470 /* Prior to 1.5.4 png_set_strip_16 would use an 'accurate' method if this
7471 * configuration option is set. From 1.5.4 the flag is never set and the
7472 * 'scale' API (above) must be used.
7473 */
7474 # ifdef PNG_READ_ACCURATE_SCALE_SUPPORTED
7475 # if PNG_LIBPNG_VER >= 10504
7476 # error PNG_READ_ACCURATE_SCALE should not be set
7477 # endif
7478
7479 /* The strip 16 algorithm drops the low 8 bits rather than calculating
7480 * 1/257, so we need to adjust the permitted errors appropriately:
7481 * Notice that this is only relevant prior to the addition of the
7482 * png_set_scale_16 API in 1.5.4 (but 1.5.4+ always defines the above!)
7483 */
7484 {
7485 const double d = (255-128.5)/65535;
7486 that->rede += d;
7487 that->greene += d;
7488 that->bluee += d;
7489 that->alphae += d;
7490 }
7491 # endif
7492 }
7493
7494 this->next->mod(this->next, that, pp, display);
7495 }
7496
7497 static int
image_transform_png_set_strip_16_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)7498 image_transform_png_set_strip_16_add(image_transform *this,
7499 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7500 {
7501 UNUSED(colour_type)
7502
7503 this->next = *that;
7504 *that = this;
7505
7506 return bit_depth > 8;
7507 }
7508
7509 IT(strip_16);
7510 #undef PT
7511 #define PT ITSTRUCT(strip_16)
7512 #endif /* PNG_READ_16_TO_8_SUPPORTED */
7513
7514 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
7515 /* png_set_strip_alpha */
7516 static void
image_transform_png_set_strip_alpha_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)7517 image_transform_png_set_strip_alpha_set(const image_transform *this,
7518 transform_display *that, png_structp pp, png_infop pi)
7519 {
7520 png_set_strip_alpha(pp);
7521 this->next->set(this->next, that, pp, pi);
7522 }
7523
7524 static void
image_transform_png_set_strip_alpha_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)7525 image_transform_png_set_strip_alpha_mod(const image_transform *this,
7526 image_pixel *that, png_const_structp pp,
7527 const transform_display *display)
7528 {
7529 if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
7530 that->colour_type = PNG_COLOR_TYPE_GRAY;
7531 else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
7532 that->colour_type = PNG_COLOR_TYPE_RGB;
7533
7534 that->have_tRNS = 0;
7535 that->alphaf = 1;
7536
7537 this->next->mod(this->next, that, pp, display);
7538 }
7539
7540 static int
image_transform_png_set_strip_alpha_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)7541 image_transform_png_set_strip_alpha_add(image_transform *this,
7542 const image_transform **that, png_byte colour_type, png_byte bit_depth)
7543 {
7544 UNUSED(bit_depth)
7545
7546 this->next = *that;
7547 *that = this;
7548
7549 return (colour_type & PNG_COLOR_MASK_ALPHA) != 0;
7550 }
7551
7552 IT(strip_alpha);
7553 #undef PT
7554 #define PT ITSTRUCT(strip_alpha)
7555 #endif /* PNG_READ_STRIP_ALPHA_SUPPORTED */
7556
7557 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
7558 /* png_set_rgb_to_gray(png_structp, int err_action, double red, double green)
7559 * png_set_rgb_to_gray_fixed(png_structp, int err_action, png_fixed_point red,
7560 * png_fixed_point green)
7561 * png_get_rgb_to_gray_status
7562 *
7563 * The 'default' test here uses values known to be used inside libpng prior to
7564 * 1.7.0:
7565 *
7566 * red: 6968
7567 * green: 23434
7568 * blue: 2366
7569 *
7570 * These values are being retained for compatibility, along with the somewhat
7571 * broken truncation calculation in the fast-and-inaccurate code path. Older
7572 * versions of libpng will fail the accuracy tests below because they use the
7573 * truncation algorithm everywhere.
7574 */
7575 #define data ITDATA(rgb_to_gray)
7576 static struct
7577 {
7578 double gamma; /* File gamma to use in processing */
7579
7580 /* The following are the parameters for png_set_rgb_to_gray: */
7581 # ifdef PNG_FLOATING_POINT_SUPPORTED
7582 double red_to_set;
7583 double green_to_set;
7584 # else
7585 png_fixed_point red_to_set;
7586 png_fixed_point green_to_set;
7587 # endif
7588
7589 /* The actual coefficients: */
7590 double red_coefficient;
7591 double green_coefficient;
7592 double blue_coefficient;
7593
7594 /* Set if the coeefficients have been overridden. */
7595 int coefficients_overridden;
7596 } data;
7597
7598 #undef image_transform_ini
7599 #define image_transform_ini image_transform_png_set_rgb_to_gray_ini
7600 static void
image_transform_png_set_rgb_to_gray_ini(const image_transform * this,transform_display * that)7601 image_transform_png_set_rgb_to_gray_ini(const image_transform *this,
7602 transform_display *that)
7603 {
7604 png_modifier *pm = that->pm;
7605 const color_encoding *e = pm->current_encoding;
7606
7607 UNUSED(this)
7608
7609 /* Since we check the encoding this flag must be set: */
7610 pm->test_uses_encoding = 1;
7611
7612 /* If 'e' is not NULL chromaticity information is present and either a cHRM
7613 * or an sRGB chunk will be inserted.
7614 */
7615 if (e != 0)
7616 {
7617 /* Coefficients come from the encoding, but may need to be normalized to a
7618 * white point Y of 1.0
7619 */
7620 const double whiteY = e->red.Y + e->green.Y + e->blue.Y;
7621
7622 data.red_coefficient = e->red.Y;
7623 data.green_coefficient = e->green.Y;
7624 data.blue_coefficient = e->blue.Y;
7625
7626 if (whiteY != 1)
7627 {
7628 data.red_coefficient /= whiteY;
7629 data.green_coefficient /= whiteY;
7630 data.blue_coefficient /= whiteY;
7631 }
7632 }
7633
7634 else
7635 {
7636 /* The default (built in) coeffcients, as above: */
7637 # if PNG_LIBPNG_VER < 10700
7638 data.red_coefficient = 6968 / 32768.;
7639 data.green_coefficient = 23434 / 32768.;
7640 data.blue_coefficient = 2366 / 32768.;
7641 # else
7642 data.red_coefficient = .2126;
7643 data.green_coefficient = .7152;
7644 data.blue_coefficient = .0722;
7645 # endif
7646 }
7647
7648 data.gamma = pm->current_gamma;
7649
7650 /* If not set then the calculations assume linear encoding (implicitly): */
7651 if (data.gamma == 0)
7652 data.gamma = 1;
7653
7654 /* The arguments to png_set_rgb_to_gray can override the coefficients implied
7655 * by the color space encoding. If doing exhaustive checks do the override
7656 * in each case, otherwise do it randomly.
7657 */
7658 if (pm->test_exhaustive)
7659 {
7660 /* First time in coefficients_overridden is 0, the following sets it to 1,
7661 * so repeat if it is set. If a test fails this may mean we subsequently
7662 * skip a non-override test, ignore that.
7663 */
7664 data.coefficients_overridden = !data.coefficients_overridden;
7665 pm->repeat = data.coefficients_overridden != 0;
7666 }
7667
7668 else
7669 data.coefficients_overridden = random_choice();
7670
7671 if (data.coefficients_overridden)
7672 {
7673 /* These values override the color encoding defaults, simply use random
7674 * numbers.
7675 */
7676 png_uint_32 ru;
7677 double total;
7678
7679 ru = random_u32();
7680 data.green_coefficient = total = (ru & 0xffff) / 65535.;
7681 ru >>= 16;
7682 data.red_coefficient = (1 - total) * (ru & 0xffff) / 65535.;
7683 total += data.red_coefficient;
7684 data.blue_coefficient = 1 - total;
7685
7686 # ifdef PNG_FLOATING_POINT_SUPPORTED
7687 data.red_to_set = data.red_coefficient;
7688 data.green_to_set = data.green_coefficient;
7689 # else
7690 data.red_to_set = fix(data.red_coefficient);
7691 data.green_to_set = fix(data.green_coefficient);
7692 # endif
7693
7694 /* The following just changes the error messages: */
7695 pm->encoding_ignored = 1;
7696 }
7697
7698 else
7699 {
7700 data.red_to_set = -1;
7701 data.green_to_set = -1;
7702 }
7703
7704 /* Adjust the error limit in the png_modifier because of the larger errors
7705 * produced in the digitization during the gamma handling.
7706 */
7707 if (data.gamma != 1) /* Use gamma tables */
7708 {
7709 if (that->this.bit_depth == 16 || pm->assume_16_bit_calculations)
7710 {
7711 /* The computations have the form:
7712 *
7713 * r * rc + g * gc + b * bc
7714 *
7715 * Each component of which is +/-1/65535 from the gamma_to_1 table
7716 * lookup, resulting in a base error of +/-6. The gamma_from_1
7717 * conversion adds another +/-2 in the 16-bit case and
7718 * +/-(1<<(15-PNG_MAX_GAMMA_8)) in the 8-bit case.
7719 */
7720 # if PNG_LIBPNG_VER < 10700
7721 if (that->this.bit_depth < 16)
7722 that->max_gamma_8 = PNG_MAX_GAMMA_8;
7723 # endif
7724 that->pm->limit += pow(
7725 (that->this.bit_depth == 16 || that->max_gamma_8 > 14 ?
7726 8. :
7727 6. + (1<<(15-that->max_gamma_8))
7728 )/65535, data.gamma);
7729 }
7730
7731 else
7732 {
7733 /* Rounding to 8 bits in the linear space causes massive errors which
7734 * will trigger the error check in transform_range_check. Fix that
7735 * here by taking the gamma encoding into account.
7736 *
7737 * When DIGITIZE is set because a pre-1.7 version of libpng is being
7738 * tested allow a bigger slack.
7739 *
7740 * NOTE: this number only affects the internal limit check in pngvalid,
7741 * it has no effect on the limits applied to the libpng values.
7742 */
7743 that->pm->limit += pow(
7744 # if DIGITIZE
7745 2.0
7746 # else
7747 1.0
7748 # endif
7749 /255, data.gamma);
7750 }
7751 }
7752
7753 else
7754 {
7755 /* With no gamma correction a large error comes from the truncation of the
7756 * calculation in the 8 bit case, allow for that here.
7757 */
7758 if (that->this.bit_depth != 16 && !pm->assume_16_bit_calculations)
7759 that->pm->limit += 4E-3;
7760 }
7761 }
7762
7763 static void
image_transform_png_set_rgb_to_gray_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)7764 image_transform_png_set_rgb_to_gray_set(const image_transform *this,
7765 transform_display *that, png_structp pp, png_infop pi)
7766 {
7767 const int error_action = 1; /* no error, no defines in png.h */
7768
7769 # ifdef PNG_FLOATING_POINT_SUPPORTED
7770 png_set_rgb_to_gray(pp, error_action, data.red_to_set, data.green_to_set);
7771 # else
7772 png_set_rgb_to_gray_fixed(pp, error_action, data.red_to_set,
7773 data.green_to_set);
7774 # endif
7775
7776 # ifdef PNG_READ_cHRM_SUPPORTED
7777 if (that->pm->current_encoding != 0)
7778 {
7779 /* We have an encoding so a cHRM chunk may have been set; if so then
7780 * check that the libpng APIs give the correct (X,Y,Z) values within
7781 * some margin of error for the round trip through the chromaticity
7782 * form.
7783 */
7784 # ifdef PNG_FLOATING_POINT_SUPPORTED
7785 # define API_function png_get_cHRM_XYZ
7786 # define API_form "FP"
7787 # define API_type double
7788 # define API_cvt(x) (x)
7789 # else
7790 # define API_function png_get_cHRM_XYZ_fixed
7791 # define API_form "fixed"
7792 # define API_type png_fixed_point
7793 # define API_cvt(x) ((double)(x)/PNG_FP_1)
7794 # endif
7795
7796 API_type rX, gX, bX;
7797 API_type rY, gY, bY;
7798 API_type rZ, gZ, bZ;
7799
7800 if ((API_function(pp, pi, &rX, &rY, &rZ, &gX, &gY, &gZ, &bX, &bY, &bZ)
7801 & PNG_INFO_cHRM) != 0)
7802 {
7803 double maxe;
7804 const char *el;
7805 color_encoding e, o;
7806
7807 /* Expect libpng to return a normalized result, but the original
7808 * color space encoding may not be normalized.
7809 */
7810 modifier_current_encoding(that->pm, &o);
7811 normalize_color_encoding(&o);
7812
7813 /* Sanity check the pngvalid code - the coefficients should match
7814 * the normalized Y values of the encoding unless they were
7815 * overridden.
7816 */
7817 if (data.red_to_set == -1 && data.green_to_set == -1 &&
7818 (fabs(o.red.Y - data.red_coefficient) > DBL_EPSILON ||
7819 fabs(o.green.Y - data.green_coefficient) > DBL_EPSILON ||
7820 fabs(o.blue.Y - data.blue_coefficient) > DBL_EPSILON))
7821 png_error(pp, "internal pngvalid cHRM coefficient error");
7822
7823 /* Generate a colour space encoding. */
7824 e.gamma = o.gamma; /* not used */
7825 e.red.X = API_cvt(rX);
7826 e.red.Y = API_cvt(rY);
7827 e.red.Z = API_cvt(rZ);
7828 e.green.X = API_cvt(gX);
7829 e.green.Y = API_cvt(gY);
7830 e.green.Z = API_cvt(gZ);
7831 e.blue.X = API_cvt(bX);
7832 e.blue.Y = API_cvt(bY);
7833 e.blue.Z = API_cvt(bZ);
7834
7835 /* This should match the original one from the png_modifier, within
7836 * the range permitted by the libpng fixed point representation.
7837 */
7838 maxe = 0;
7839 el = "-"; /* Set to element name with error */
7840
7841 # define CHECK(col,x)\
7842 {\
7843 double err = fabs(o.col.x - e.col.x);\
7844 if (err > maxe)\
7845 {\
7846 maxe = err;\
7847 el = #col "(" #x ")";\
7848 }\
7849 }
7850
7851 CHECK(red,X)
7852 CHECK(red,Y)
7853 CHECK(red,Z)
7854 CHECK(green,X)
7855 CHECK(green,Y)
7856 CHECK(green,Z)
7857 CHECK(blue,X)
7858 CHECK(blue,Y)
7859 CHECK(blue,Z)
7860
7861 /* Here in both fixed and floating cases to check the values read
7862 * from the cHRm chunk. PNG uses fixed point in the cHRM chunk, so
7863 * we can't expect better than +/-.5E-5 on the result, allow 1E-5.
7864 */
7865 if (maxe >= 1E-5)
7866 {
7867 size_t pos = 0;
7868 char buffer[256];
7869
7870 pos = safecat(buffer, sizeof buffer, pos, API_form);
7871 pos = safecat(buffer, sizeof buffer, pos, " cHRM ");
7872 pos = safecat(buffer, sizeof buffer, pos, el);
7873 pos = safecat(buffer, sizeof buffer, pos, " error: ");
7874 pos = safecatd(buffer, sizeof buffer, pos, maxe, 7);
7875 pos = safecat(buffer, sizeof buffer, pos, " ");
7876 /* Print the color space without the gamma value: */
7877 pos = safecat_color_encoding(buffer, sizeof buffer, pos, &o, 0);
7878 pos = safecat(buffer, sizeof buffer, pos, " -> ");
7879 pos = safecat_color_encoding(buffer, sizeof buffer, pos, &e, 0);
7880
7881 png_error(pp, buffer);
7882 }
7883 }
7884 }
7885 # endif /* READ_cHRM */
7886
7887 this->next->set(this->next, that, pp, pi);
7888 }
7889
7890 static void
image_transform_png_set_rgb_to_gray_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)7891 image_transform_png_set_rgb_to_gray_mod(const image_transform *this,
7892 image_pixel *that, png_const_structp pp,
7893 const transform_display *display)
7894 {
7895 if ((that->colour_type & PNG_COLOR_MASK_COLOR) != 0)
7896 {
7897 double gray, err;
7898
7899 # if PNG_LIBPNG_VER < 10700
7900 if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
7901 image_pixel_convert_PLTE(that);
7902 # endif
7903
7904 /* Image now has RGB channels... */
7905 # if DIGITIZE
7906 {
7907 png_modifier *pm = display->pm;
7908 const unsigned int sample_depth = that->sample_depth;
7909 const unsigned int calc_depth = (pm->assume_16_bit_calculations ? 16 :
7910 sample_depth);
7911 const unsigned int gamma_depth =
7912 (sample_depth == 16 ?
7913 display->max_gamma_8 :
7914 (pm->assume_16_bit_calculations ?
7915 display->max_gamma_8 :
7916 sample_depth));
7917 int isgray;
7918 double r, g, b;
7919 double rlo, rhi, glo, ghi, blo, bhi, graylo, grayhi;
7920
7921 /* Do this using interval arithmetic, otherwise it is too difficult to
7922 * handle the errors correctly.
7923 *
7924 * To handle the gamma correction work out the upper and lower bounds
7925 * of the digitized value. Assume rounding here - normally the values
7926 * will be identical after this operation if there is only one
7927 * transform, feel free to delete the png_error checks on this below in
7928 * the future (this is just me trying to ensure it works!)
7929 *
7930 * Interval arithmetic is exact, but to implement it it must be
7931 * possible to control the floating point implementation rounding mode.
7932 * This cannot be done in ANSI-C, so instead I reduce the 'lo' values
7933 * by DBL_EPSILON and increase the 'hi' values by the same.
7934 */
7935 # define DD(v,d,r) (digitize(v*(1-DBL_EPSILON), d, r) * (1-DBL_EPSILON))
7936 # define DU(v,d,r) (digitize(v*(1+DBL_EPSILON), d, r) * (1+DBL_EPSILON))
7937
7938 r = rlo = rhi = that->redf;
7939 rlo -= that->rede;
7940 rlo = DD(rlo, calc_depth, 1/*round*/);
7941 rhi += that->rede;
7942 rhi = DU(rhi, calc_depth, 1/*round*/);
7943
7944 g = glo = ghi = that->greenf;
7945 glo -= that->greene;
7946 glo = DD(glo, calc_depth, 1/*round*/);
7947 ghi += that->greene;
7948 ghi = DU(ghi, calc_depth, 1/*round*/);
7949
7950 b = blo = bhi = that->bluef;
7951 blo -= that->bluee;
7952 blo = DD(blo, calc_depth, 1/*round*/);
7953 bhi += that->bluee;
7954 bhi = DU(bhi, calc_depth, 1/*round*/);
7955
7956 isgray = r==g && g==b;
7957
7958 if (data.gamma != 1)
7959 {
7960 const double power = 1/data.gamma;
7961 const double abse = .5/(sample_depth == 16 ? 65535 : 255);
7962
7963 /* If a gamma calculation is done it is done using lookup tables of
7964 * precision gamma_depth, so the already digitized value above may
7965 * need to be further digitized here.
7966 */
7967 if (gamma_depth != calc_depth)
7968 {
7969 rlo = DD(rlo, gamma_depth, 0/*truncate*/);
7970 rhi = DU(rhi, gamma_depth, 0/*truncate*/);
7971 glo = DD(glo, gamma_depth, 0/*truncate*/);
7972 ghi = DU(ghi, gamma_depth, 0/*truncate*/);
7973 blo = DD(blo, gamma_depth, 0/*truncate*/);
7974 bhi = DU(bhi, gamma_depth, 0/*truncate*/);
7975 }
7976
7977 /* 'abse' is the error in the gamma table calculation itself. */
7978 r = pow(r, power);
7979 rlo = DD(pow(rlo, power)-abse, calc_depth, 1);
7980 rhi = DU(pow(rhi, power)+abse, calc_depth, 1);
7981
7982 g = pow(g, power);
7983 glo = DD(pow(glo, power)-abse, calc_depth, 1);
7984 ghi = DU(pow(ghi, power)+abse, calc_depth, 1);
7985
7986 b = pow(b, power);
7987 blo = DD(pow(blo, power)-abse, calc_depth, 1);
7988 bhi = DU(pow(bhi, power)+abse, calc_depth, 1);
7989 }
7990
7991 /* Now calculate the actual gray values. Although the error in the
7992 * coefficients depends on whether they were specified on the command
7993 * line (in which case truncation to 15 bits happened) or not (rounding
7994 * was used) the maxium error in an individual coefficient is always
7995 * 2/32768, because even in the rounding case the requirement that
7996 * coefficients add up to 32768 can cause a larger rounding error.
7997 *
7998 * The only time when rounding doesn't occur in 1.5.5 and later is when
7999 * the non-gamma code path is used for less than 16 bit data.
8000 */
8001 gray = r * data.red_coefficient + g * data.green_coefficient +
8002 b * data.blue_coefficient;
8003
8004 {
8005 const int do_round = data.gamma != 1 || calc_depth == 16;
8006 const double ce = 2. / 32768;
8007
8008 graylo = DD(rlo * (data.red_coefficient-ce) +
8009 glo * (data.green_coefficient-ce) +
8010 blo * (data.blue_coefficient-ce), calc_depth, do_round);
8011 if (graylo > gray) /* always accept the right answer */
8012 graylo = gray;
8013
8014 grayhi = DU(rhi * (data.red_coefficient+ce) +
8015 ghi * (data.green_coefficient+ce) +
8016 bhi * (data.blue_coefficient+ce), calc_depth, do_round);
8017 if (grayhi < gray)
8018 grayhi = gray;
8019 }
8020
8021 /* And invert the gamma. */
8022 if (data.gamma != 1)
8023 {
8024 const double power = data.gamma;
8025
8026 /* And this happens yet again, shifting the values once more. */
8027 if (gamma_depth != sample_depth)
8028 {
8029 rlo = DD(rlo, gamma_depth, 0/*truncate*/);
8030 rhi = DU(rhi, gamma_depth, 0/*truncate*/);
8031 glo = DD(glo, gamma_depth, 0/*truncate*/);
8032 ghi = DU(ghi, gamma_depth, 0/*truncate*/);
8033 blo = DD(blo, gamma_depth, 0/*truncate*/);
8034 bhi = DU(bhi, gamma_depth, 0/*truncate*/);
8035 }
8036
8037 gray = pow(gray, power);
8038 graylo = DD(pow(graylo, power), sample_depth, 1);
8039 grayhi = DU(pow(grayhi, power), sample_depth, 1);
8040 }
8041
8042 # undef DD
8043 # undef DU
8044
8045 /* Now the error can be calculated.
8046 *
8047 * If r==g==b because there is no overall gamma correction libpng
8048 * currently preserves the original value.
8049 */
8050 if (isgray)
8051 err = (that->rede + that->greene + that->bluee)/3;
8052
8053 else
8054 {
8055 err = fabs(grayhi-gray);
8056
8057 if (fabs(gray - graylo) > err)
8058 err = fabs(graylo-gray);
8059
8060 #if !RELEASE_BUILD
8061 /* Check that this worked: */
8062 if (err > pm->limit)
8063 {
8064 size_t pos = 0;
8065 char buffer[128];
8066
8067 pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
8068 pos = safecatd(buffer, sizeof buffer, pos, err, 6);
8069 pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
8070 pos = safecatd(buffer, sizeof buffer, pos, pm->limit, 6);
8071 png_warning(pp, buffer);
8072 pm->limit = err;
8073 }
8074 #endif /* !RELEASE_BUILD */
8075 }
8076 }
8077 # else /* !DIGITIZE */
8078 {
8079 double r = that->redf;
8080 double re = that->rede;
8081 double g = that->greenf;
8082 double ge = that->greene;
8083 double b = that->bluef;
8084 double be = that->bluee;
8085
8086 # if PNG_LIBPNG_VER < 10700
8087 /* The true gray case involves no math in earlier versions (not
8088 * true, there was some if gamma correction was happening too.)
8089 */
8090 if (r == g && r == b)
8091 {
8092 gray = r;
8093 err = re;
8094 if (err < ge) err = ge;
8095 if (err < be) err = be;
8096 }
8097
8098 else
8099 # endif /* before 1.7 */
8100 if (data.gamma == 1)
8101 {
8102 /* There is no need to do the conversions to and from linear space,
8103 * so the calculation should be a lot more accurate. There is a
8104 * built in error in the coefficients because they only have 15 bits
8105 * and are adjusted to make sure they add up to 32768. This
8106 * involves a integer calculation with truncation of the form:
8107 *
8108 * ((int)(coefficient * 100000) * 32768)/100000
8109 *
8110 * This is done to the red and green coefficients (the ones
8111 * provided to the API) then blue is calculated from them so the
8112 * result adds up to 32768. In the worst case this can result in
8113 * a -1 error in red and green and a +2 error in blue. Consequently
8114 * the worst case in the calculation below is 2/32768 error.
8115 *
8116 * TODO: consider fixing this in libpng by rounding the calculation
8117 * limiting the error to 1/32768.
8118 *
8119 * Handling this by adding 2/32768 here avoids needing to increase
8120 * the global error limits to take this into account.)
8121 */
8122 gray = r * data.red_coefficient + g * data.green_coefficient +
8123 b * data.blue_coefficient;
8124 err = re * data.red_coefficient + ge * data.green_coefficient +
8125 be * data.blue_coefficient + 2./32768 + gray * 5 * DBL_EPSILON;
8126 }
8127
8128 else
8129 {
8130 /* The calculation happens in linear space, and this produces much
8131 * wider errors in the encoded space. These are handled here by
8132 * factoring the errors in to the calculation. There are two table
8133 * lookups in the calculation and each introduces a quantization
8134 * error defined by the table size.
8135 */
8136 png_modifier *pm = display->pm;
8137 double in_qe = (that->sample_depth > 8 ? .5/65535 : .5/255);
8138 double out_qe = (that->sample_depth > 8 ? .5/65535 :
8139 (pm->assume_16_bit_calculations ? .5/(1<<display->max_gamma_8) :
8140 .5/255));
8141 double rhi, ghi, bhi, grayhi;
8142 double g1 = 1/data.gamma;
8143
8144 rhi = r + re + in_qe; if (rhi > 1) rhi = 1;
8145 r -= re + in_qe; if (r < 0) r = 0;
8146 ghi = g + ge + in_qe; if (ghi > 1) ghi = 1;
8147 g -= ge + in_qe; if (g < 0) g = 0;
8148 bhi = b + be + in_qe; if (bhi > 1) bhi = 1;
8149 b -= be + in_qe; if (b < 0) b = 0;
8150
8151 r = pow(r, g1)*(1-DBL_EPSILON); rhi = pow(rhi, g1)*(1+DBL_EPSILON);
8152 g = pow(g, g1)*(1-DBL_EPSILON); ghi = pow(ghi, g1)*(1+DBL_EPSILON);
8153 b = pow(b, g1)*(1-DBL_EPSILON); bhi = pow(bhi, g1)*(1+DBL_EPSILON);
8154
8155 /* Work out the lower and upper bounds for the gray value in the
8156 * encoded space, then work out an average and error. Remove the
8157 * previously added input quantization error at this point.
8158 */
8159 gray = r * data.red_coefficient + g * data.green_coefficient +
8160 b * data.blue_coefficient - 2./32768 - out_qe;
8161 if (gray <= 0)
8162 gray = 0;
8163 else
8164 {
8165 gray *= (1 - 6 * DBL_EPSILON);
8166 gray = pow(gray, data.gamma) * (1-DBL_EPSILON);
8167 }
8168
8169 grayhi = rhi * data.red_coefficient + ghi * data.green_coefficient +
8170 bhi * data.blue_coefficient + 2./32768 + out_qe;
8171 grayhi *= (1 + 6 * DBL_EPSILON);
8172 if (grayhi >= 1)
8173 grayhi = 1;
8174 else
8175 grayhi = pow(grayhi, data.gamma) * (1+DBL_EPSILON);
8176
8177 err = (grayhi - gray) / 2;
8178 gray = (grayhi + gray) / 2;
8179
8180 if (err <= in_qe)
8181 err = gray * DBL_EPSILON;
8182
8183 else
8184 err -= in_qe;
8185
8186 #if !RELEASE_BUILD
8187 /* Validate that the error is within limits (this has caused
8188 * problems before, it's much easier to detect them here.)
8189 */
8190 if (err > pm->limit)
8191 {
8192 size_t pos = 0;
8193 char buffer[128];
8194
8195 pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
8196 pos = safecatd(buffer, sizeof buffer, pos, err, 6);
8197 pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
8198 pos = safecatd(buffer, sizeof buffer, pos, pm->limit, 6);
8199 png_warning(pp, buffer);
8200 pm->limit = err;
8201 }
8202 #endif /* !RELEASE_BUILD */
8203 }
8204 }
8205 # endif /* !DIGITIZE */
8206
8207 that->bluef = that->greenf = that->redf = gray;
8208 that->bluee = that->greene = that->rede = err;
8209
8210 /* The sBIT is the minium of the three colour channel sBITs. */
8211 if (that->red_sBIT > that->green_sBIT)
8212 that->red_sBIT = that->green_sBIT;
8213 if (that->red_sBIT > that->blue_sBIT)
8214 that->red_sBIT = that->blue_sBIT;
8215 that->blue_sBIT = that->green_sBIT = that->red_sBIT;
8216
8217 /* And remove the colour bit in the type: */
8218 if (that->colour_type == PNG_COLOR_TYPE_RGB)
8219 that->colour_type = PNG_COLOR_TYPE_GRAY;
8220 else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
8221 that->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
8222 }
8223
8224 this->next->mod(this->next, that, pp, display);
8225 }
8226
8227 static int
image_transform_png_set_rgb_to_gray_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)8228 image_transform_png_set_rgb_to_gray_add(image_transform *this,
8229 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8230 {
8231 UNUSED(bit_depth)
8232
8233 this->next = *that;
8234 *that = this;
8235
8236 return (colour_type & PNG_COLOR_MASK_COLOR) != 0;
8237 }
8238
8239 #undef data
8240 IT(rgb_to_gray);
8241 #undef PT
8242 #define PT ITSTRUCT(rgb_to_gray)
8243 #undef image_transform_ini
8244 #define image_transform_ini image_transform_default_ini
8245 #endif /* PNG_READ_RGB_TO_GRAY_SUPPORTED */
8246
8247 #ifdef PNG_READ_BACKGROUND_SUPPORTED
8248 /* png_set_background(png_structp, png_const_color_16p background_color,
8249 * int background_gamma_code, int need_expand, double background_gamma)
8250 * png_set_background_fixed(png_structp, png_const_color_16p background_color,
8251 * int background_gamma_code, int need_expand,
8252 * png_fixed_point background_gamma)
8253 *
8254 * This ignores the gamma (at present.)
8255 */
8256 #define data ITDATA(background)
8257 static image_pixel data;
8258
8259 static void
image_transform_png_set_background_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)8260 image_transform_png_set_background_set(const image_transform *this,
8261 transform_display *that, png_structp pp, png_infop pi)
8262 {
8263 png_byte colour_type, bit_depth;
8264 png_byte random_bytes[8]; /* 8 bytes - 64 bits - the biggest pixel */
8265 int expand;
8266 png_color_16 back;
8267
8268 /* We need a background colour, because we don't know exactly what transforms
8269 * have been set we have to supply the colour in the original file format and
8270 * so we need to know what that is! The background colour is stored in the
8271 * transform_display.
8272 */
8273 R8(random_bytes);
8274
8275 /* Read the random value, for colour type 3 the background colour is actually
8276 * expressed as a 24bit rgb, not an index.
8277 */
8278 colour_type = that->this.colour_type;
8279 if (colour_type == 3)
8280 {
8281 colour_type = PNG_COLOR_TYPE_RGB;
8282 bit_depth = 8;
8283 expand = 0; /* passing in an RGB not a pixel index */
8284 }
8285
8286 else
8287 {
8288 if (that->this.has_tRNS)
8289 that->this.is_transparent = 1;
8290
8291 bit_depth = that->this.bit_depth;
8292 expand = 1;
8293 }
8294
8295 image_pixel_init(&data, random_bytes, colour_type,
8296 bit_depth, 0/*x*/, 0/*unused: palette*/, NULL/*format*/);
8297
8298 /* Extract the background colour from this image_pixel, but make sure the
8299 * unused fields of 'back' are garbage.
8300 */
8301 R8(back);
8302
8303 if (colour_type & PNG_COLOR_MASK_COLOR)
8304 {
8305 back.red = (png_uint_16)data.red;
8306 back.green = (png_uint_16)data.green;
8307 back.blue = (png_uint_16)data.blue;
8308 }
8309
8310 else
8311 back.gray = (png_uint_16)data.red;
8312
8313 #ifdef PNG_FLOATING_POINT_SUPPORTED
8314 png_set_background(pp, &back, PNG_BACKGROUND_GAMMA_FILE, expand, 0);
8315 #else
8316 png_set_background_fixed(pp, &back, PNG_BACKGROUND_GAMMA_FILE, expand, 0);
8317 #endif
8318
8319 this->next->set(this->next, that, pp, pi);
8320 }
8321
8322 static void
image_transform_png_set_background_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)8323 image_transform_png_set_background_mod(const image_transform *this,
8324 image_pixel *that, png_const_structp pp,
8325 const transform_display *display)
8326 {
8327 /* Check for tRNS first: */
8328 if (that->have_tRNS && that->colour_type != PNG_COLOR_TYPE_PALETTE)
8329 image_pixel_add_alpha(that, &display->this, 1/*for background*/);
8330
8331 /* This is only necessary if the alpha value is less than 1. */
8332 if (that->alphaf < 1)
8333 {
8334 /* Now we do the background calculation without any gamma correction. */
8335 if (that->alphaf <= 0)
8336 {
8337 that->redf = data.redf;
8338 that->greenf = data.greenf;
8339 that->bluef = data.bluef;
8340
8341 that->rede = data.rede;
8342 that->greene = data.greene;
8343 that->bluee = data.bluee;
8344
8345 that->red_sBIT= data.red_sBIT;
8346 that->green_sBIT= data.green_sBIT;
8347 that->blue_sBIT= data.blue_sBIT;
8348 }
8349
8350 else /* 0 < alpha < 1 */
8351 {
8352 double alf = 1 - that->alphaf;
8353
8354 that->redf = that->redf * that->alphaf + data.redf * alf;
8355 that->rede = that->rede * that->alphaf + data.rede * alf +
8356 DBL_EPSILON;
8357 that->greenf = that->greenf * that->alphaf + data.greenf * alf;
8358 that->greene = that->greene * that->alphaf + data.greene * alf +
8359 DBL_EPSILON;
8360 that->bluef = that->bluef * that->alphaf + data.bluef * alf;
8361 that->bluee = that->bluee * that->alphaf + data.bluee * alf +
8362 DBL_EPSILON;
8363 }
8364
8365 /* Remove the alpha type and set the alpha (not in that order.) */
8366 that->alphaf = 1;
8367 that->alphae = 0;
8368 }
8369
8370 if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
8371 that->colour_type = PNG_COLOR_TYPE_RGB;
8372 else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
8373 that->colour_type = PNG_COLOR_TYPE_GRAY;
8374 /* PNG_COLOR_TYPE_PALETTE is not changed */
8375
8376 this->next->mod(this->next, that, pp, display);
8377 }
8378
8379 #define image_transform_png_set_background_add image_transform_default_add
8380
8381 #undef data
8382 IT(background);
8383 #undef PT
8384 #define PT ITSTRUCT(background)
8385 #endif /* PNG_READ_BACKGROUND_SUPPORTED */
8386
8387 /* png_set_quantize(png_structp, png_colorp palette, int num_palette,
8388 * int maximum_colors, png_const_uint_16p histogram, int full_quantize)
8389 *
8390 * Very difficult to validate this!
8391 */
8392 /*NOTE: TBD NYI */
8393
8394 /* The data layout transforms are handled by swapping our own channel data,
8395 * necessarily these need to happen at the end of the transform list because the
8396 * semantic of the channels changes after these are executed. Some of these,
8397 * like set_shift and set_packing, can't be done at present because they change
8398 * the layout of the data at the sub-sample level so sample() won't get the
8399 * right answer.
8400 */
8401 /* png_set_invert_alpha */
8402 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
8403 /* Invert the alpha channel
8404 *
8405 * png_set_invert_alpha(png_structrp png_ptr)
8406 */
8407 static void
image_transform_png_set_invert_alpha_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)8408 image_transform_png_set_invert_alpha_set(const image_transform *this,
8409 transform_display *that, png_structp pp, png_infop pi)
8410 {
8411 png_set_invert_alpha(pp);
8412 this->next->set(this->next, that, pp, pi);
8413 }
8414
8415 static void
image_transform_png_set_invert_alpha_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)8416 image_transform_png_set_invert_alpha_mod(const image_transform *this,
8417 image_pixel *that, png_const_structp pp,
8418 const transform_display *display)
8419 {
8420 if (that->colour_type & 4)
8421 that->alpha_inverted = 1;
8422
8423 this->next->mod(this->next, that, pp, display);
8424 }
8425
8426 static int
image_transform_png_set_invert_alpha_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)8427 image_transform_png_set_invert_alpha_add(image_transform *this,
8428 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8429 {
8430 UNUSED(bit_depth)
8431
8432 this->next = *that;
8433 *that = this;
8434
8435 /* Only has an effect on pixels with alpha: */
8436 return (colour_type & 4) != 0;
8437 }
8438
8439 IT(invert_alpha);
8440 #undef PT
8441 #define PT ITSTRUCT(invert_alpha)
8442
8443 #endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */
8444
8445 /* png_set_bgr */
8446 #ifdef PNG_READ_BGR_SUPPORTED
8447 /* Swap R,G,B channels to order B,G,R.
8448 *
8449 * png_set_bgr(png_structrp png_ptr)
8450 *
8451 * This only has an effect on RGB and RGBA pixels.
8452 */
8453 static void
image_transform_png_set_bgr_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)8454 image_transform_png_set_bgr_set(const image_transform *this,
8455 transform_display *that, png_structp pp, png_infop pi)
8456 {
8457 png_set_bgr(pp);
8458 this->next->set(this->next, that, pp, pi);
8459 }
8460
8461 static void
image_transform_png_set_bgr_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)8462 image_transform_png_set_bgr_mod(const image_transform *this,
8463 image_pixel *that, png_const_structp pp,
8464 const transform_display *display)
8465 {
8466 if (that->colour_type == PNG_COLOR_TYPE_RGB ||
8467 that->colour_type == PNG_COLOR_TYPE_RGBA)
8468 that->swap_rgb = 1;
8469
8470 this->next->mod(this->next, that, pp, display);
8471 }
8472
8473 static int
image_transform_png_set_bgr_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)8474 image_transform_png_set_bgr_add(image_transform *this,
8475 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8476 {
8477 UNUSED(bit_depth)
8478
8479 this->next = *that;
8480 *that = this;
8481
8482 return colour_type == PNG_COLOR_TYPE_RGB ||
8483 colour_type == PNG_COLOR_TYPE_RGBA;
8484 }
8485
8486 IT(bgr);
8487 #undef PT
8488 #define PT ITSTRUCT(bgr)
8489
8490 #endif /* PNG_READ_BGR_SUPPORTED */
8491
8492 /* png_set_swap_alpha */
8493 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
8494 /* Put the alpha channel first.
8495 *
8496 * png_set_swap_alpha(png_structrp png_ptr)
8497 *
8498 * This only has an effect on GA and RGBA pixels.
8499 */
8500 static void
image_transform_png_set_swap_alpha_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)8501 image_transform_png_set_swap_alpha_set(const image_transform *this,
8502 transform_display *that, png_structp pp, png_infop pi)
8503 {
8504 png_set_swap_alpha(pp);
8505 this->next->set(this->next, that, pp, pi);
8506 }
8507
8508 static void
image_transform_png_set_swap_alpha_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)8509 image_transform_png_set_swap_alpha_mod(const image_transform *this,
8510 image_pixel *that, png_const_structp pp,
8511 const transform_display *display)
8512 {
8513 if (that->colour_type == PNG_COLOR_TYPE_GA ||
8514 that->colour_type == PNG_COLOR_TYPE_RGBA)
8515 that->alpha_first = 1;
8516
8517 this->next->mod(this->next, that, pp, display);
8518 }
8519
8520 static int
image_transform_png_set_swap_alpha_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)8521 image_transform_png_set_swap_alpha_add(image_transform *this,
8522 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8523 {
8524 UNUSED(bit_depth)
8525
8526 this->next = *that;
8527 *that = this;
8528
8529 return colour_type == PNG_COLOR_TYPE_GA ||
8530 colour_type == PNG_COLOR_TYPE_RGBA;
8531 }
8532
8533 IT(swap_alpha);
8534 #undef PT
8535 #define PT ITSTRUCT(swap_alpha)
8536
8537 #endif /* PNG_READ_SWAP_ALPHA_SUPPORTED */
8538
8539 /* png_set_swap */
8540 #ifdef PNG_READ_SWAP_SUPPORTED
8541 /* Byte swap 16-bit components.
8542 *
8543 * png_set_swap(png_structrp png_ptr)
8544 */
8545 static void
image_transform_png_set_swap_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)8546 image_transform_png_set_swap_set(const image_transform *this,
8547 transform_display *that, png_structp pp, png_infop pi)
8548 {
8549 png_set_swap(pp);
8550 this->next->set(this->next, that, pp, pi);
8551 }
8552
8553 static void
image_transform_png_set_swap_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)8554 image_transform_png_set_swap_mod(const image_transform *this,
8555 image_pixel *that, png_const_structp pp,
8556 const transform_display *display)
8557 {
8558 if (that->bit_depth == 16)
8559 that->swap16 = 1;
8560
8561 this->next->mod(this->next, that, pp, display);
8562 }
8563
8564 static int
image_transform_png_set_swap_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)8565 image_transform_png_set_swap_add(image_transform *this,
8566 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8567 {
8568 UNUSED(colour_type)
8569
8570 this->next = *that;
8571 *that = this;
8572
8573 return bit_depth == 16;
8574 }
8575
8576 IT(swap);
8577 #undef PT
8578 #define PT ITSTRUCT(swap)
8579
8580 #endif /* PNG_READ_SWAP_SUPPORTED */
8581
8582 #ifdef PNG_READ_FILLER_SUPPORTED
8583 /* Add a filler byte to 8-bit Gray or 24-bit RGB images.
8584 *
8585 * png_set_filler, (png_structp png_ptr, png_uint_32 filler, int flags));
8586 *
8587 * Flags:
8588 *
8589 * PNG_FILLER_BEFORE
8590 * PNG_FILLER_AFTER
8591 */
8592 #define data ITDATA(filler)
8593 static struct
8594 {
8595 png_uint_32 filler;
8596 int flags;
8597 } data;
8598
8599 static void
image_transform_png_set_filler_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)8600 image_transform_png_set_filler_set(const image_transform *this,
8601 transform_display *that, png_structp pp, png_infop pi)
8602 {
8603 /* Need a random choice for 'before' and 'after' as well as for the
8604 * filler. The 'filler' value has all 32 bits set, but only bit_depth
8605 * will be used. At this point we don't know bit_depth.
8606 */
8607 data.filler = random_u32();
8608 data.flags = random_choice();
8609
8610 png_set_filler(pp, data.filler, data.flags);
8611
8612 /* The standard display handling stuff also needs to know that
8613 * there is a filler, so set that here.
8614 */
8615 that->this.filler = 1;
8616
8617 this->next->set(this->next, that, pp, pi);
8618 }
8619
8620 static void
image_transform_png_set_filler_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)8621 image_transform_png_set_filler_mod(const image_transform *this,
8622 image_pixel *that, png_const_structp pp,
8623 const transform_display *display)
8624 {
8625 if (that->bit_depth >= 8 &&
8626 (that->colour_type == PNG_COLOR_TYPE_RGB ||
8627 that->colour_type == PNG_COLOR_TYPE_GRAY))
8628 {
8629 const unsigned int max = (1U << that->bit_depth)-1;
8630 that->alpha = data.filler & max;
8631 that->alphaf = ((double)that->alpha) / max;
8632 that->alphae = 0;
8633
8634 /* The filler has been stored in the alpha channel, we must record
8635 * that this has been done for the checking later on, the color
8636 * type is faked to have an alpha channel, but libpng won't report
8637 * this; the app has to know the extra channel is there and this
8638 * was recording in standard_display::filler above.
8639 */
8640 that->colour_type |= 4; /* alpha added */
8641 that->alpha_first = data.flags == PNG_FILLER_BEFORE;
8642 }
8643
8644 this->next->mod(this->next, that, pp, display);
8645 }
8646
8647 static int
image_transform_png_set_filler_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)8648 image_transform_png_set_filler_add(image_transform *this,
8649 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8650 {
8651 this->next = *that;
8652 *that = this;
8653
8654 return bit_depth >= 8 && (colour_type == PNG_COLOR_TYPE_RGB ||
8655 colour_type == PNG_COLOR_TYPE_GRAY);
8656 }
8657
8658 #undef data
8659 IT(filler);
8660 #undef PT
8661 #define PT ITSTRUCT(filler)
8662
8663 /* png_set_add_alpha, (png_structp png_ptr, png_uint_32 filler, int flags)); */
8664 /* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
8665 #define data ITDATA(add_alpha)
8666 static struct
8667 {
8668 png_uint_32 filler;
8669 int flags;
8670 } data;
8671
8672 static void
image_transform_png_set_add_alpha_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)8673 image_transform_png_set_add_alpha_set(const image_transform *this,
8674 transform_display *that, png_structp pp, png_infop pi)
8675 {
8676 /* Need a random choice for 'before' and 'after' as well as for the
8677 * filler. The 'filler' value has all 32 bits set, but only bit_depth
8678 * will be used. At this point we don't know bit_depth.
8679 */
8680 data.filler = random_u32();
8681 data.flags = random_choice();
8682
8683 png_set_add_alpha(pp, data.filler, data.flags);
8684 this->next->set(this->next, that, pp, pi);
8685 }
8686
8687 static void
image_transform_png_set_add_alpha_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)8688 image_transform_png_set_add_alpha_mod(const image_transform *this,
8689 image_pixel *that, png_const_structp pp,
8690 const transform_display *display)
8691 {
8692 if (that->bit_depth >= 8 &&
8693 (that->colour_type == PNG_COLOR_TYPE_RGB ||
8694 that->colour_type == PNG_COLOR_TYPE_GRAY))
8695 {
8696 const unsigned int max = (1U << that->bit_depth)-1;
8697 that->alpha = data.filler & max;
8698 that->alphaf = ((double)that->alpha) / max;
8699 that->alphae = 0;
8700
8701 that->colour_type |= 4; /* alpha added */
8702 that->alpha_first = data.flags == PNG_FILLER_BEFORE;
8703 }
8704
8705 this->next->mod(this->next, that, pp, display);
8706 }
8707
8708 static int
image_transform_png_set_add_alpha_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)8709 image_transform_png_set_add_alpha_add(image_transform *this,
8710 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8711 {
8712 this->next = *that;
8713 *that = this;
8714
8715 return bit_depth >= 8 && (colour_type == PNG_COLOR_TYPE_RGB ||
8716 colour_type == PNG_COLOR_TYPE_GRAY);
8717 }
8718
8719 #undef data
8720 IT(add_alpha);
8721 #undef PT
8722 #define PT ITSTRUCT(add_alpha)
8723
8724 #endif /* PNG_READ_FILLER_SUPPORTED */
8725
8726 /* png_set_packing */
8727 #ifdef PNG_READ_PACK_SUPPORTED
8728 /* Use 1 byte per pixel in 1, 2, or 4-bit depth files.
8729 *
8730 * png_set_packing(png_structrp png_ptr)
8731 *
8732 * This should only affect grayscale and palette images with less than 8 bits
8733 * per pixel.
8734 */
8735 static void
image_transform_png_set_packing_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)8736 image_transform_png_set_packing_set(const image_transform *this,
8737 transform_display *that, png_structp pp, png_infop pi)
8738 {
8739 png_set_packing(pp);
8740 that->unpacked = 1;
8741 this->next->set(this->next, that, pp, pi);
8742 }
8743
8744 static void
image_transform_png_set_packing_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)8745 image_transform_png_set_packing_mod(const image_transform *this,
8746 image_pixel *that, png_const_structp pp,
8747 const transform_display *display)
8748 {
8749 /* The general expand case depends on what the colour type is,
8750 * low bit-depth pixel values are unpacked into bytes without
8751 * scaling, so sample_depth is not changed.
8752 */
8753 if (that->bit_depth < 8) /* grayscale or palette */
8754 that->bit_depth = 8;
8755
8756 this->next->mod(this->next, that, pp, display);
8757 }
8758
8759 static int
image_transform_png_set_packing_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)8760 image_transform_png_set_packing_add(image_transform *this,
8761 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8762 {
8763 UNUSED(colour_type)
8764
8765 this->next = *that;
8766 *that = this;
8767
8768 /* Nothing should happen unless the bit depth is less than 8: */
8769 return bit_depth < 8;
8770 }
8771
8772 IT(packing);
8773 #undef PT
8774 #define PT ITSTRUCT(packing)
8775
8776 #endif /* PNG_READ_PACK_SUPPORTED */
8777
8778 /* png_set_packswap */
8779 #ifdef PNG_READ_PACKSWAP_SUPPORTED
8780 /* Swap pixels packed into bytes; reverses the order on screen so that
8781 * the high order bits correspond to the rightmost pixels.
8782 *
8783 * png_set_packswap(png_structrp png_ptr)
8784 */
8785 static void
image_transform_png_set_packswap_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)8786 image_transform_png_set_packswap_set(const image_transform *this,
8787 transform_display *that, png_structp pp, png_infop pi)
8788 {
8789 png_set_packswap(pp);
8790 that->this.littleendian = 1;
8791 this->next->set(this->next, that, pp, pi);
8792 }
8793
8794 static void
image_transform_png_set_packswap_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)8795 image_transform_png_set_packswap_mod(const image_transform *this,
8796 image_pixel *that, png_const_structp pp,
8797 const transform_display *display)
8798 {
8799 if (that->bit_depth < 8)
8800 that->littleendian = 1;
8801
8802 this->next->mod(this->next, that, pp, display);
8803 }
8804
8805 static int
image_transform_png_set_packswap_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)8806 image_transform_png_set_packswap_add(image_transform *this,
8807 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8808 {
8809 UNUSED(colour_type)
8810
8811 this->next = *that;
8812 *that = this;
8813
8814 return bit_depth < 8;
8815 }
8816
8817 IT(packswap);
8818 #undef PT
8819 #define PT ITSTRUCT(packswap)
8820
8821 #endif /* PNG_READ_PACKSWAP_SUPPORTED */
8822
8823
8824 /* png_set_invert_mono */
8825 #ifdef PNG_READ_INVERT_MONO_SUPPORTED
8826 /* Invert the gray channel
8827 *
8828 * png_set_invert_mono(png_structrp png_ptr)
8829 */
8830 static void
image_transform_png_set_invert_mono_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)8831 image_transform_png_set_invert_mono_set(const image_transform *this,
8832 transform_display *that, png_structp pp, png_infop pi)
8833 {
8834 png_set_invert_mono(pp);
8835 this->next->set(this->next, that, pp, pi);
8836 }
8837
8838 static void
image_transform_png_set_invert_mono_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)8839 image_transform_png_set_invert_mono_mod(const image_transform *this,
8840 image_pixel *that, png_const_structp pp,
8841 const transform_display *display)
8842 {
8843 if (that->colour_type & 4)
8844 that->mono_inverted = 1;
8845
8846 this->next->mod(this->next, that, pp, display);
8847 }
8848
8849 static int
image_transform_png_set_invert_mono_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)8850 image_transform_png_set_invert_mono_add(image_transform *this,
8851 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8852 {
8853 UNUSED(bit_depth)
8854
8855 this->next = *that;
8856 *that = this;
8857
8858 /* Only has an effect on pixels with no colour: */
8859 return (colour_type & 2) == 0;
8860 }
8861
8862 IT(invert_mono);
8863 #undef PT
8864 #define PT ITSTRUCT(invert_mono)
8865
8866 #endif /* PNG_READ_INVERT_MONO_SUPPORTED */
8867
8868 #ifdef PNG_READ_SHIFT_SUPPORTED
8869 /* png_set_shift(png_structp, png_const_color_8p true_bits)
8870 *
8871 * The output pixels will be shifted by the given true_bits
8872 * values.
8873 */
8874 #define data ITDATA(shift)
8875 static png_color_8 data;
8876
8877 static void
image_transform_png_set_shift_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)8878 image_transform_png_set_shift_set(const image_transform *this,
8879 transform_display *that, png_structp pp, png_infop pi)
8880 {
8881 /* Get a random set of shifts. The shifts need to do something
8882 * to test the transform, so they are limited to the bit depth
8883 * of the input image. Notice that in the following the 'gray'
8884 * field is randomized independently. This acts as a check that
8885 * libpng does use the correct field.
8886 */
8887 const unsigned int depth = that->this.bit_depth;
8888
8889 data.red = (png_byte)/*SAFE*/(random_mod(depth)+1);
8890 data.green = (png_byte)/*SAFE*/(random_mod(depth)+1);
8891 data.blue = (png_byte)/*SAFE*/(random_mod(depth)+1);
8892 data.gray = (png_byte)/*SAFE*/(random_mod(depth)+1);
8893 data.alpha = (png_byte)/*SAFE*/(random_mod(depth)+1);
8894
8895 png_set_shift(pp, &data);
8896 this->next->set(this->next, that, pp, pi);
8897 }
8898
8899 static void
image_transform_png_set_shift_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)8900 image_transform_png_set_shift_mod(const image_transform *this,
8901 image_pixel *that, png_const_structp pp,
8902 const transform_display *display)
8903 {
8904 /* Copy the correct values into the sBIT fields, libpng does not do
8905 * anything to palette data:
8906 */
8907 if (that->colour_type != PNG_COLOR_TYPE_PALETTE)
8908 {
8909 that->sig_bits = 1;
8910
8911 /* The sBIT fields are reset to the values previously sent to
8912 * png_set_shift according to the colour type.
8913 * does.
8914 */
8915 if (that->colour_type & 2) /* RGB channels */
8916 {
8917 that->red_sBIT = data.red;
8918 that->green_sBIT = data.green;
8919 that->blue_sBIT = data.blue;
8920 }
8921
8922 else /* One grey channel */
8923 that->red_sBIT = that->green_sBIT = that->blue_sBIT = data.gray;
8924
8925 that->alpha_sBIT = data.alpha;
8926 }
8927
8928 this->next->mod(this->next, that, pp, display);
8929 }
8930
8931 static int
image_transform_png_set_shift_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)8932 image_transform_png_set_shift_add(image_transform *this,
8933 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8934 {
8935 UNUSED(bit_depth)
8936
8937 this->next = *that;
8938 *that = this;
8939
8940 return colour_type != PNG_COLOR_TYPE_PALETTE;
8941 }
8942
8943 IT(shift);
8944 #undef PT
8945 #define PT ITSTRUCT(shift)
8946
8947 #endif /* PNG_READ_SHIFT_SUPPORTED */
8948
8949 #ifdef THIS_IS_THE_PROFORMA
8950 static void
_set(const image_transform * this,transform_display * that,png_structp pp,png_infop pi)8951 image_transform_png_set_@_set(const image_transform *this,
8952 transform_display *that, png_structp pp, png_infop pi)
8953 {
8954 png_set_@(pp);
8955 this->next->set(this->next, that, pp, pi);
8956 }
8957
8958 static void
_mod(const image_transform * this,image_pixel * that,png_const_structp pp,const transform_display * display)8959 image_transform_png_set_@_mod(const image_transform *this,
8960 image_pixel *that, png_const_structp pp,
8961 const transform_display *display)
8962 {
8963 this->next->mod(this->next, that, pp, display);
8964 }
8965
8966 static int
_add(image_transform * this,const image_transform ** that,png_byte colour_type,png_byte bit_depth)8967 image_transform_png_set_@_add(image_transform *this,
8968 const image_transform **that, png_byte colour_type, png_byte bit_depth)
8969 {
8970 this->next = *that;
8971 *that = this;
8972
8973 return 1;
8974 }
8975
8976 IT(@);
8977 #endif
8978
8979
8980 /* This may just be 'end' if all the transforms are disabled! */
8981 static image_transform *const image_transform_first = &PT;
8982
8983 static void
transform_enable(const char * name)8984 transform_enable(const char *name)
8985 {
8986 /* Everything starts out enabled, so if we see an 'enable' disabled
8987 * everything else the first time round.
8988 */
8989 static int all_disabled = 0;
8990 int found_it = 0;
8991 image_transform *list = image_transform_first;
8992
8993 while (list != &image_transform_end)
8994 {
8995 if (strcmp(list->name, name) == 0)
8996 {
8997 list->enable = 1;
8998 found_it = 1;
8999 }
9000 else if (!all_disabled)
9001 list->enable = 0;
9002
9003 list = list->list;
9004 }
9005
9006 all_disabled = 1;
9007
9008 if (!found_it)
9009 {
9010 fprintf(stderr, "pngvalid: --transform-enable=%s: unknown transform\n",
9011 name);
9012 exit(99);
9013 }
9014 }
9015
9016 static void
transform_disable(const char * name)9017 transform_disable(const char *name)
9018 {
9019 image_transform *list = image_transform_first;
9020
9021 while (list != &image_transform_end)
9022 {
9023 if (strcmp(list->name, name) == 0)
9024 {
9025 list->enable = 0;
9026 return;
9027 }
9028
9029 list = list->list;
9030 }
9031
9032 fprintf(stderr, "pngvalid: --transform-disable=%s: unknown transform\n",
9033 name);
9034 exit(99);
9035 }
9036
9037 static void
image_transform_reset_count(void)9038 image_transform_reset_count(void)
9039 {
9040 image_transform *next = image_transform_first;
9041 int count = 0;
9042
9043 while (next != &image_transform_end)
9044 {
9045 next->local_use = 0;
9046 next->next = 0;
9047 next = next->list;
9048 ++count;
9049 }
9050
9051 /* This can only happen if we every have more than 32 transforms (excluding
9052 * the end) in the list.
9053 */
9054 if (count > 32) abort();
9055 }
9056
9057 static int
image_transform_test_counter(png_uint_32 counter,unsigned int max)9058 image_transform_test_counter(png_uint_32 counter, unsigned int max)
9059 {
9060 /* Test the list to see if there is any point contining, given a current
9061 * counter and a 'max' value.
9062 */
9063 image_transform *next = image_transform_first;
9064
9065 while (next != &image_transform_end)
9066 {
9067 /* For max 0 or 1 continue until the counter overflows: */
9068 counter >>= 1;
9069
9070 /* Continue if any entry hasn't reacked the max. */
9071 if (max > 1 && next->local_use < max)
9072 return 1;
9073 next = next->list;
9074 }
9075
9076 return max <= 1 && counter == 0;
9077 }
9078
9079 static png_uint_32
image_transform_add(const image_transform ** this,unsigned int max,png_uint_32 counter,char * name,size_t sizeof_name,size_t * pos,png_byte colour_type,png_byte bit_depth)9080 image_transform_add(const image_transform **this, unsigned int max,
9081 png_uint_32 counter, char *name, size_t sizeof_name, size_t *pos,
9082 png_byte colour_type, png_byte bit_depth)
9083 {
9084 for (;;) /* until we manage to add something */
9085 {
9086 png_uint_32 mask;
9087 image_transform *list;
9088
9089 /* Find the next counter value, if the counter is zero this is the start
9090 * of the list. This routine always returns the current counter (not the
9091 * next) so it returns 0 at the end and expects 0 at the beginning.
9092 */
9093 if (counter == 0) /* first time */
9094 {
9095 image_transform_reset_count();
9096 if (max <= 1)
9097 counter = 1;
9098 else
9099 counter = random_32();
9100 }
9101 else /* advance the counter */
9102 {
9103 switch (max)
9104 {
9105 case 0: ++counter; break;
9106 case 1: counter <<= 1; break;
9107 default: counter = random_32(); break;
9108 }
9109 }
9110
9111 /* Now add all these items, if possible */
9112 *this = &image_transform_end;
9113 list = image_transform_first;
9114 mask = 1;
9115
9116 /* Go through the whole list adding anything that the counter selects: */
9117 while (list != &image_transform_end)
9118 {
9119 if ((counter & mask) != 0 && list->enable &&
9120 (max == 0 || list->local_use < max))
9121 {
9122 /* Candidate to add: */
9123 if (list->add(list, this, colour_type, bit_depth) || max == 0)
9124 {
9125 /* Added, so add to the name too. */
9126 *pos = safecat(name, sizeof_name, *pos, " +");
9127 *pos = safecat(name, sizeof_name, *pos, list->name);
9128 }
9129
9130 else
9131 {
9132 /* Not useful and max>0, so remove it from *this: */
9133 *this = list->next;
9134 list->next = 0;
9135
9136 /* And, since we know it isn't useful, stop it being added again
9137 * in this run:
9138 */
9139 list->local_use = max;
9140 }
9141 }
9142
9143 mask <<= 1;
9144 list = list->list;
9145 }
9146
9147 /* Now if anything was added we have something to do. */
9148 if (*this != &image_transform_end)
9149 return counter;
9150
9151 /* Nothing added, but was there anything in there to add? */
9152 if (!image_transform_test_counter(counter, max))
9153 return 0;
9154 }
9155 }
9156
9157 static void
perform_transform_test(png_modifier * pm)9158 perform_transform_test(png_modifier *pm)
9159 {
9160 png_byte colour_type = 0;
9161 png_byte bit_depth = 0;
9162 unsigned int palette_number = 0;
9163
9164 while (next_format(&colour_type, &bit_depth, &palette_number, pm->test_lbg,
9165 pm->test_tRNS))
9166 {
9167 png_uint_32 counter = 0;
9168 size_t base_pos;
9169 char name[64];
9170
9171 base_pos = safecat(name, sizeof name, 0, "transform:");
9172
9173 for (;;)
9174 {
9175 size_t pos = base_pos;
9176 const image_transform *list = 0;
9177
9178 /* 'max' is currently hardwired to '1'; this should be settable on the
9179 * command line.
9180 */
9181 counter = image_transform_add(&list, 1/*max*/, counter,
9182 name, sizeof name, &pos, colour_type, bit_depth);
9183
9184 if (counter == 0)
9185 break;
9186
9187 /* The command line can change this to checking interlaced images. */
9188 do
9189 {
9190 pm->repeat = 0;
9191 transform_test(pm, FILEID(colour_type, bit_depth, palette_number,
9192 pm->interlace_type, 0, 0, 0), list, name);
9193
9194 if (fail(pm))
9195 return;
9196 }
9197 while (pm->repeat);
9198 }
9199 }
9200 }
9201 #endif /* PNG_READ_TRANSFORMS_SUPPORTED */
9202
9203 /********************************* GAMMA TESTS ********************************/
9204 #ifdef PNG_READ_GAMMA_SUPPORTED
9205 /* Reader callbacks and implementations, where they differ from the standard
9206 * ones.
9207 */
9208 typedef struct gamma_display
9209 {
9210 standard_display this;
9211
9212 /* Parameters */
9213 png_modifier* pm;
9214 double file_gamma;
9215 double screen_gamma;
9216 double background_gamma;
9217 png_byte sbit;
9218 int threshold_test;
9219 int use_input_precision;
9220 int scale16;
9221 int expand16;
9222 int do_background;
9223 png_color_16 background_color;
9224
9225 /* Local variables */
9226 double maxerrout;
9227 double maxerrpc;
9228 double maxerrabs;
9229 } gamma_display;
9230
9231 #define ALPHA_MODE_OFFSET 4
9232
9233 static void
gamma_display_init(gamma_display * dp,png_modifier * pm,png_uint_32 id,double file_gamma,double screen_gamma,png_byte sbit,int threshold_test,int use_input_precision,int scale16,int expand16,int do_background,const png_color_16 * pointer_to_the_background_color,double background_gamma)9234 gamma_display_init(gamma_display *dp, png_modifier *pm, png_uint_32 id,
9235 double file_gamma, double screen_gamma, png_byte sbit, int threshold_test,
9236 int use_input_precision, int scale16, int expand16,
9237 int do_background, const png_color_16 *pointer_to_the_background_color,
9238 double background_gamma)
9239 {
9240 /* Standard fields */
9241 standard_display_init(&dp->this, &pm->this, id, do_read_interlace,
9242 pm->use_update_info);
9243
9244 /* Parameter fields */
9245 dp->pm = pm;
9246 dp->file_gamma = file_gamma;
9247 dp->screen_gamma = screen_gamma;
9248 dp->background_gamma = background_gamma;
9249 dp->sbit = sbit;
9250 dp->threshold_test = threshold_test;
9251 dp->use_input_precision = use_input_precision;
9252 dp->scale16 = scale16;
9253 dp->expand16 = expand16;
9254 dp->do_background = do_background;
9255 if (do_background && pointer_to_the_background_color != 0)
9256 dp->background_color = *pointer_to_the_background_color;
9257 else
9258 memset(&dp->background_color, 0, sizeof dp->background_color);
9259
9260 /* Local variable fields */
9261 dp->maxerrout = dp->maxerrpc = dp->maxerrabs = 0;
9262 }
9263
9264 static void
gamma_info_imp(gamma_display * dp,png_structp pp,png_infop pi)9265 gamma_info_imp(gamma_display *dp, png_structp pp, png_infop pi)
9266 {
9267 /* Reuse the standard stuff as appropriate. */
9268 standard_info_part1(&dp->this, pp, pi);
9269
9270 /* If requested strip 16 to 8 bits - this is handled automagically below
9271 * because the output bit depth is read from the library. Note that there
9272 * are interactions with sBIT but, internally, libpng makes sbit at most
9273 * PNG_MAX_GAMMA_8 prior to 1.7 when doing the following.
9274 */
9275 if (dp->scale16)
9276 # ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
9277 png_set_scale_16(pp);
9278 # else
9279 /* The following works both in 1.5.4 and earlier versions: */
9280 # ifdef PNG_READ_16_TO_8_SUPPORTED
9281 png_set_strip_16(pp);
9282 # else
9283 png_error(pp, "scale16 (16 to 8 bit conversion) not supported");
9284 # endif
9285 # endif
9286
9287 if (dp->expand16)
9288 # ifdef PNG_READ_EXPAND_16_SUPPORTED
9289 png_set_expand_16(pp);
9290 # else
9291 png_error(pp, "expand16 (8 to 16 bit conversion) not supported");
9292 # endif
9293
9294 if (dp->do_background >= ALPHA_MODE_OFFSET)
9295 {
9296 # ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9297 {
9298 /* This tests the alpha mode handling, if supported. */
9299 int mode = dp->do_background - ALPHA_MODE_OFFSET;
9300
9301 /* The gamma value is the output gamma, and is in the standard,
9302 * non-inverted, represenation. It provides a default for the PNG file
9303 * gamma, but since the file has a gAMA chunk this does not matter.
9304 */
9305 const double sg = dp->screen_gamma;
9306 # ifndef PNG_FLOATING_POINT_SUPPORTED
9307 const png_fixed_point g = fix(sg);
9308 # endif
9309
9310 # ifdef PNG_FLOATING_POINT_SUPPORTED
9311 png_set_alpha_mode(pp, mode, sg);
9312 # else
9313 png_set_alpha_mode_fixed(pp, mode, g);
9314 # endif
9315
9316 /* However, for the standard Porter-Duff algorithm the output defaults
9317 * to be linear, so if the test requires non-linear output it must be
9318 * corrected here.
9319 */
9320 if (mode == PNG_ALPHA_STANDARD && sg != 1)
9321 {
9322 # ifdef PNG_FLOATING_POINT_SUPPORTED
9323 png_set_gamma(pp, sg, dp->file_gamma);
9324 # else
9325 png_fixed_point f = fix(dp->file_gamma);
9326 png_set_gamma_fixed(pp, g, f);
9327 # endif
9328 }
9329 }
9330 # else
9331 png_error(pp, "alpha mode handling not supported");
9332 # endif
9333 }
9334
9335 else
9336 {
9337 /* Set up gamma processing. */
9338 # ifdef PNG_FLOATING_POINT_SUPPORTED
9339 png_set_gamma(pp, dp->screen_gamma, dp->file_gamma);
9340 # else
9341 {
9342 png_fixed_point s = fix(dp->screen_gamma);
9343 png_fixed_point f = fix(dp->file_gamma);
9344 png_set_gamma_fixed(pp, s, f);
9345 }
9346 # endif
9347
9348 if (dp->do_background)
9349 {
9350 # ifdef PNG_READ_BACKGROUND_SUPPORTED
9351 /* NOTE: this assumes the caller provided the correct background gamma!
9352 */
9353 const double bg = dp->background_gamma;
9354 # ifndef PNG_FLOATING_POINT_SUPPORTED
9355 const png_fixed_point g = fix(bg);
9356 # endif
9357
9358 # ifdef PNG_FLOATING_POINT_SUPPORTED
9359 png_set_background(pp, &dp->background_color, dp->do_background,
9360 0/*need_expand*/, bg);
9361 # else
9362 png_set_background_fixed(pp, &dp->background_color,
9363 dp->do_background, 0/*need_expand*/, g);
9364 # endif
9365 # else
9366 png_error(pp, "png_set_background not supported");
9367 # endif
9368 }
9369 }
9370
9371 {
9372 int i = dp->this.use_update_info;
9373 /* Always do one call, even if use_update_info is 0. */
9374 do
9375 png_read_update_info(pp, pi);
9376 while (--i > 0);
9377 }
9378
9379 /* Now we may get a different cbRow: */
9380 standard_info_part2(&dp->this, pp, pi, 1 /*images*/);
9381 }
9382
9383 static void PNGCBAPI
gamma_info(png_structp pp,png_infop pi)9384 gamma_info(png_structp pp, png_infop pi)
9385 {
9386 gamma_info_imp(voidcast(gamma_display*, png_get_progressive_ptr(pp)), pp,
9387 pi);
9388 }
9389
9390 /* Validate a single component value - the routine gets the input and output
9391 * sample values as unscaled PNG component values along with a cache of all the
9392 * information required to validate the values.
9393 */
9394 typedef struct validate_info
9395 {
9396 png_const_structp pp;
9397 gamma_display *dp;
9398 png_byte sbit;
9399 int use_input_precision;
9400 int do_background;
9401 int scale16;
9402 unsigned int sbit_max;
9403 unsigned int isbit_shift;
9404 unsigned int outmax;
9405
9406 double gamma_correction; /* Overall correction required. */
9407 double file_inverse; /* Inverse of file gamma. */
9408 double screen_gamma;
9409 double screen_inverse; /* Inverse of screen gamma. */
9410
9411 double background_red; /* Linear background value, red or gray. */
9412 double background_green;
9413 double background_blue;
9414
9415 double maxabs;
9416 double maxpc;
9417 double maxcalc;
9418 double maxout;
9419 double maxout_total; /* Total including quantization error */
9420 double outlog;
9421 int outquant;
9422 }
9423 validate_info;
9424
9425 static void
init_validate_info(validate_info * vi,gamma_display * dp,png_const_structp pp,int in_depth,int out_depth)9426 init_validate_info(validate_info *vi, gamma_display *dp, png_const_structp pp,
9427 int in_depth, int out_depth)
9428 {
9429 const unsigned int outmax = (1U<<out_depth)-1;
9430
9431 vi->pp = pp;
9432 vi->dp = dp;
9433
9434 if (dp->sbit > 0 && dp->sbit < in_depth)
9435 {
9436 vi->sbit = dp->sbit;
9437 vi->isbit_shift = in_depth - dp->sbit;
9438 }
9439
9440 else
9441 {
9442 vi->sbit = (png_byte)in_depth;
9443 vi->isbit_shift = 0;
9444 }
9445
9446 vi->sbit_max = (1U << vi->sbit)-1;
9447
9448 /* This mimics the libpng threshold test, '0' is used to prevent gamma
9449 * correction in the validation test.
9450 */
9451 vi->screen_gamma = dp->screen_gamma;
9452 if (fabs(vi->screen_gamma-1) < PNG_GAMMA_THRESHOLD)
9453 vi->screen_gamma = vi->screen_inverse = 0;
9454 else
9455 vi->screen_inverse = 1/vi->screen_gamma;
9456
9457 vi->use_input_precision = dp->use_input_precision;
9458 vi->outmax = outmax;
9459 vi->maxabs = abserr(dp->pm, in_depth, out_depth);
9460 vi->maxpc = pcerr(dp->pm, in_depth, out_depth);
9461 vi->maxcalc = calcerr(dp->pm, in_depth, out_depth);
9462 vi->maxout = outerr(dp->pm, in_depth, out_depth);
9463 vi->outquant = output_quantization_factor(dp->pm, in_depth, out_depth);
9464 vi->maxout_total = vi->maxout + vi->outquant * .5;
9465 vi->outlog = outlog(dp->pm, in_depth, out_depth);
9466
9467 if ((dp->this.colour_type & PNG_COLOR_MASK_ALPHA) != 0 ||
9468 (dp->this.colour_type == 3 && dp->this.is_transparent) ||
9469 ((dp->this.colour_type == 0 || dp->this.colour_type == 2) &&
9470 dp->this.has_tRNS))
9471 {
9472 vi->do_background = dp->do_background;
9473
9474 if (vi->do_background != 0)
9475 {
9476 const double bg_inverse = 1/dp->background_gamma;
9477 double r, g, b;
9478
9479 /* Caller must at least put the gray value into the red channel */
9480 r = dp->background_color.red; r /= outmax;
9481 g = dp->background_color.green; g /= outmax;
9482 b = dp->background_color.blue; b /= outmax;
9483
9484 # if 0
9485 /* libpng doesn't do this optimization, if we do pngvalid will fail.
9486 */
9487 if (fabs(bg_inverse-1) >= PNG_GAMMA_THRESHOLD)
9488 # endif
9489 {
9490 r = pow(r, bg_inverse);
9491 g = pow(g, bg_inverse);
9492 b = pow(b, bg_inverse);
9493 }
9494
9495 vi->background_red = r;
9496 vi->background_green = g;
9497 vi->background_blue = b;
9498 }
9499 }
9500 else /* Do not expect any background processing */
9501 vi->do_background = 0;
9502
9503 if (vi->do_background == 0)
9504 vi->background_red = vi->background_green = vi->background_blue = 0;
9505
9506 vi->gamma_correction = 1/(dp->file_gamma*dp->screen_gamma);
9507 if (fabs(vi->gamma_correction-1) < PNG_GAMMA_THRESHOLD)
9508 vi->gamma_correction = 0;
9509
9510 vi->file_inverse = 1/dp->file_gamma;
9511 if (fabs(vi->file_inverse-1) < PNG_GAMMA_THRESHOLD)
9512 vi->file_inverse = 0;
9513
9514 vi->scale16 = dp->scale16;
9515 }
9516
9517 /* This function handles composition of a single non-alpha component. The
9518 * argument is the input sample value, in the range 0..1, and the alpha value.
9519 * The result is the composed, linear, input sample. If alpha is less than zero
9520 * this is the alpha component and the function should not be called!
9521 */
9522 static double
gamma_component_compose(int do_background,double input_sample,double alpha,double background,int * compose)9523 gamma_component_compose(int do_background, double input_sample, double alpha,
9524 double background, int *compose)
9525 {
9526 switch (do_background)
9527 {
9528 #ifdef PNG_READ_BACKGROUND_SUPPORTED
9529 case PNG_BACKGROUND_GAMMA_SCREEN:
9530 case PNG_BACKGROUND_GAMMA_FILE:
9531 case PNG_BACKGROUND_GAMMA_UNIQUE:
9532 /* Standard PNG background processing. */
9533 if (alpha < 1)
9534 {
9535 if (alpha > 0)
9536 {
9537 input_sample = input_sample * alpha + background * (1-alpha);
9538 if (compose != NULL)
9539 *compose = 1;
9540 }
9541
9542 else
9543 input_sample = background;
9544 }
9545 break;
9546 #endif
9547
9548 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9549 case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
9550 case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
9551 /* The components are premultiplied in either case and the output is
9552 * gamma encoded (to get standard Porter-Duff we expect the output
9553 * gamma to be set to 1.0!)
9554 */
9555 case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
9556 /* The optimization is that the partial-alpha entries are linear
9557 * while the opaque pixels are gamma encoded, but this only affects the
9558 * output encoding.
9559 */
9560 if (alpha < 1)
9561 {
9562 if (alpha > 0)
9563 {
9564 input_sample *= alpha;
9565 if (compose != NULL)
9566 *compose = 1;
9567 }
9568
9569 else
9570 input_sample = 0;
9571 }
9572 break;
9573 #endif
9574
9575 default:
9576 /* Standard cases where no compositing is done (so the component
9577 * value is already correct.)
9578 */
9579 UNUSED(alpha)
9580 UNUSED(background)
9581 UNUSED(compose)
9582 break;
9583 }
9584
9585 return input_sample;
9586 }
9587
9588 /* This API returns the encoded *input* component, in the range 0..1 */
9589 static double
gamma_component_validate(const char * name,const validate_info * vi,const unsigned int id,const unsigned int od,const double alpha,const double background)9590 gamma_component_validate(const char *name, const validate_info *vi,
9591 const unsigned int id, const unsigned int od,
9592 const double alpha /* <0 for the alpha channel itself */,
9593 const double background /* component background value */)
9594 {
9595 const unsigned int isbit = id >> vi->isbit_shift;
9596 const unsigned int sbit_max = vi->sbit_max;
9597 const unsigned int outmax = vi->outmax;
9598 const int do_background = vi->do_background;
9599
9600 double i;
9601
9602 /* First check on the 'perfect' result obtained from the digitized input
9603 * value, id, and compare this against the actual digitized result, 'od'.
9604 * 'i' is the input result in the range 0..1:
9605 */
9606 i = isbit; i /= sbit_max;
9607
9608 /* Check for the fast route: if we don't do any background composition or if
9609 * this is the alpha channel ('alpha' < 0) or if the pixel is opaque then
9610 * just use the gamma_correction field to correct to the final output gamma.
9611 */
9612 if (alpha == 1 /* opaque pixel component */ || !do_background
9613 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9614 || do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_PNG
9615 #endif
9616 || (alpha < 0 /* alpha channel */
9617 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9618 && do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN
9619 #endif
9620 ))
9621 {
9622 /* Then get the gamma corrected version of 'i' and compare to 'od', any
9623 * error less than .5 is insignificant - just quantization of the output
9624 * value to the nearest digital value (nevertheless the error is still
9625 * recorded - it's interesting ;-)
9626 */
9627 double encoded_sample = i;
9628 double encoded_error;
9629
9630 /* alpha less than 0 indicates the alpha channel, which is always linear
9631 */
9632 if (alpha >= 0 && vi->gamma_correction > 0)
9633 encoded_sample = pow(encoded_sample, vi->gamma_correction);
9634 encoded_sample *= outmax;
9635
9636 encoded_error = fabs(od-encoded_sample);
9637
9638 if (encoded_error > vi->dp->maxerrout)
9639 vi->dp->maxerrout = encoded_error;
9640
9641 if (encoded_error < vi->maxout_total && encoded_error < vi->outlog)
9642 return i;
9643 }
9644
9645 /* The slow route - attempt to do linear calculations. */
9646 /* There may be an error, or background processing is required, so calculate
9647 * the actual sample values - unencoded light intensity values. Note that in
9648 * practice these are not completely unencoded because they include a
9649 * 'viewing correction' to decrease or (normally) increase the perceptual
9650 * contrast of the image. There's nothing we can do about this - we don't
9651 * know what it is - so assume the unencoded value is perceptually linear.
9652 */
9653 {
9654 double input_sample = i; /* In range 0..1 */
9655 double output, error, encoded_sample, encoded_error;
9656 double es_lo, es_hi;
9657 int compose = 0; /* Set to one if composition done */
9658 int output_is_encoded; /* Set if encoded to screen gamma */
9659 int log_max_error = 1; /* Check maximum error values */
9660 png_const_charp pass = 0; /* Reason test passes (or 0 for fail) */
9661
9662 /* Convert to linear light (with the above caveat.) The alpha channel is
9663 * already linear.
9664 */
9665 if (alpha >= 0)
9666 {
9667 int tcompose;
9668
9669 if (vi->file_inverse > 0)
9670 input_sample = pow(input_sample, vi->file_inverse);
9671
9672 /* Handle the compose processing: */
9673 tcompose = 0;
9674 input_sample = gamma_component_compose(do_background, input_sample,
9675 alpha, background, &tcompose);
9676
9677 if (tcompose)
9678 compose = 1;
9679 }
9680
9681 /* And similarly for the output value, but we need to check the background
9682 * handling to linearize it correctly.
9683 */
9684 output = od;
9685 output /= outmax;
9686
9687 output_is_encoded = vi->screen_gamma > 0;
9688
9689 if (alpha < 0) /* The alpha channel */
9690 {
9691 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9692 if (do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN)
9693 #endif
9694 {
9695 /* In all other cases the output alpha channel is linear already,
9696 * don't log errors here, they are much larger in linear data.
9697 */
9698 output_is_encoded = 0;
9699 log_max_error = 0;
9700 }
9701 }
9702
9703 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
9704 else /* A component */
9705 {
9706 if (do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED &&
9707 alpha < 1) /* the optimized case - linear output */
9708 {
9709 if (alpha > 0) log_max_error = 0;
9710 output_is_encoded = 0;
9711 }
9712 }
9713 #endif
9714
9715 if (output_is_encoded)
9716 output = pow(output, vi->screen_gamma);
9717
9718 /* Calculate (or recalculate) the encoded_sample value and repeat the
9719 * check above (unnecessary if we took the fast route, but harmless.)
9720 */
9721 encoded_sample = input_sample;
9722 if (output_is_encoded)
9723 encoded_sample = pow(encoded_sample, vi->screen_inverse);
9724 encoded_sample *= outmax;
9725
9726 encoded_error = fabs(od-encoded_sample);
9727
9728 /* Don't log errors in the alpha channel, or the 'optimized' case,
9729 * neither are significant to the overall perception.
9730 */
9731 if (log_max_error && encoded_error > vi->dp->maxerrout)
9732 vi->dp->maxerrout = encoded_error;
9733
9734 if (encoded_error < vi->maxout_total)
9735 {
9736 if (encoded_error < vi->outlog)
9737 return i;
9738
9739 /* Test passed but error is bigger than the log limit, record why the
9740 * test passed:
9741 */
9742 pass = "less than maxout:\n";
9743 }
9744
9745 /* i: the original input value in the range 0..1
9746 *
9747 * pngvalid calculations:
9748 * input_sample: linear result; i linearized and composed, range 0..1
9749 * encoded_sample: encoded result; input_sample scaled to ouput bit depth
9750 *
9751 * libpng calculations:
9752 * output: linear result; od scaled to 0..1 and linearized
9753 * od: encoded result from libpng
9754 */
9755
9756 /* Now we have the numbers for real errors, both absolute values as as a
9757 * percentage of the correct value (output):
9758 */
9759 error = fabs(input_sample-output);
9760
9761 if (log_max_error && error > vi->dp->maxerrabs)
9762 vi->dp->maxerrabs = error;
9763
9764 /* The following is an attempt to ignore the tendency of quantization to
9765 * dominate the percentage errors for lower result values:
9766 */
9767 if (log_max_error && input_sample > .5)
9768 {
9769 double percentage_error = error/input_sample;
9770 if (percentage_error > vi->dp->maxerrpc)
9771 vi->dp->maxerrpc = percentage_error;
9772 }
9773
9774 /* Now calculate the digitization limits for 'encoded_sample' using the
9775 * 'max' values. Note that maxout is in the encoded space but maxpc and
9776 * maxabs are in linear light space.
9777 *
9778 * First find the maximum error in linear light space, range 0..1:
9779 */
9780 {
9781 double tmp = input_sample * vi->maxpc;
9782 if (tmp < vi->maxabs) tmp = vi->maxabs;
9783 /* If 'compose' is true the composition was done in linear space using
9784 * integer arithmetic. This introduces an extra error of +/- 0.5 (at
9785 * least) in the integer space used. 'maxcalc' records this, taking
9786 * into account the possibility that even for 16 bit output 8 bit space
9787 * may have been used.
9788 */
9789 if (compose && tmp < vi->maxcalc) tmp = vi->maxcalc;
9790
9791 /* The 'maxout' value refers to the encoded result, to compare with
9792 * this encode input_sample adjusted by the maximum error (tmp) above.
9793 */
9794 es_lo = encoded_sample - vi->maxout;
9795
9796 if (es_lo > 0 && input_sample-tmp > 0)
9797 {
9798 double low_value = input_sample-tmp;
9799 if (output_is_encoded)
9800 low_value = pow(low_value, vi->screen_inverse);
9801 low_value *= outmax;
9802 if (low_value < es_lo) es_lo = low_value;
9803
9804 /* Quantize this appropriately: */
9805 es_lo = ceil(es_lo / vi->outquant - .5) * vi->outquant;
9806 }
9807
9808 else
9809 es_lo = 0;
9810
9811 es_hi = encoded_sample + vi->maxout;
9812
9813 if (es_hi < outmax && input_sample+tmp < 1)
9814 {
9815 double high_value = input_sample+tmp;
9816 if (output_is_encoded)
9817 high_value = pow(high_value, vi->screen_inverse);
9818 high_value *= outmax;
9819 if (high_value > es_hi) es_hi = high_value;
9820
9821 es_hi = floor(es_hi / vi->outquant + .5) * vi->outquant;
9822 }
9823
9824 else
9825 es_hi = outmax;
9826 }
9827
9828 /* The primary test is that the final encoded value returned by the
9829 * library should be between the two limits (inclusive) that were
9830 * calculated above.
9831 */
9832 if (od >= es_lo && od <= es_hi)
9833 {
9834 /* The value passes, but we may need to log the information anyway. */
9835 if (encoded_error < vi->outlog)
9836 return i;
9837
9838 if (pass == 0)
9839 pass = "within digitization limits:\n";
9840 }
9841
9842 {
9843 /* There has been an error in processing, or we need to log this
9844 * value.
9845 */
9846 double is_lo, is_hi;
9847
9848 /* pass is set at this point if either of the tests above would have
9849 * passed. Don't do these additional tests here - just log the
9850 * original [es_lo..es_hi] values.
9851 */
9852 if (pass == 0 && vi->use_input_precision && vi->dp->sbit)
9853 {
9854 /* Ok, something is wrong - this actually happens in current libpng
9855 * 16-to-8 processing. Assume that the input value (id, adjusted
9856 * for sbit) can be anywhere between value-.5 and value+.5 - quite a
9857 * large range if sbit is low.
9858 *
9859 * NOTE: at present because the libpng gamma table stuff has been
9860 * changed to use a rounding algorithm to correct errors in 8-bit
9861 * calculations the precise sbit calculation (a shift) has been
9862 * lost. This can result in up to a +/-1 error in the presence of
9863 * an sbit less than the bit depth.
9864 */
9865 # if PNG_LIBPNG_VER < 10700
9866 # define SBIT_ERROR .5
9867 # else
9868 # define SBIT_ERROR 1.
9869 # endif
9870 double tmp = (isbit - SBIT_ERROR)/sbit_max;
9871
9872 if (tmp <= 0)
9873 tmp = 0;
9874
9875 else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
9876 tmp = pow(tmp, vi->file_inverse);
9877
9878 tmp = gamma_component_compose(do_background, tmp, alpha, background,
9879 NULL);
9880
9881 if (output_is_encoded && tmp > 0 && tmp < 1)
9882 tmp = pow(tmp, vi->screen_inverse);
9883
9884 is_lo = ceil(outmax * tmp - vi->maxout_total);
9885
9886 if (is_lo < 0)
9887 is_lo = 0;
9888
9889 tmp = (isbit + SBIT_ERROR)/sbit_max;
9890
9891 if (tmp >= 1)
9892 tmp = 1;
9893
9894 else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
9895 tmp = pow(tmp, vi->file_inverse);
9896
9897 tmp = gamma_component_compose(do_background, tmp, alpha, background,
9898 NULL);
9899
9900 if (output_is_encoded && tmp > 0 && tmp < 1)
9901 tmp = pow(tmp, vi->screen_inverse);
9902
9903 is_hi = floor(outmax * tmp + vi->maxout_total);
9904
9905 if (is_hi > outmax)
9906 is_hi = outmax;
9907
9908 if (!(od < is_lo || od > is_hi))
9909 {
9910 if (encoded_error < vi->outlog)
9911 return i;
9912
9913 pass = "within input precision limits:\n";
9914 }
9915
9916 /* One last chance. If this is an alpha channel and the 16to8
9917 * option has been used and 'inaccurate' scaling is used then the
9918 * bit reduction is obtained by simply using the top 8 bits of the
9919 * value.
9920 *
9921 * This is only done for older libpng versions when the 'inaccurate'
9922 * (chop) method of scaling was used.
9923 */
9924 # ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
9925 # if PNG_LIBPNG_VER < 10504
9926 /* This may be required for other components in the future,
9927 * but at present the presence of gamma correction effectively
9928 * prevents the errors in the component scaling (I don't quite
9929 * understand why, but since it's better this way I care not
9930 * to ask, JB 20110419.)
9931 */
9932 if (pass == 0 && alpha < 0 && vi->scale16 && vi->sbit > 8 &&
9933 vi->sbit + vi->isbit_shift == 16)
9934 {
9935 tmp = ((id >> 8) - .5)/255;
9936
9937 if (tmp > 0)
9938 {
9939 is_lo = ceil(outmax * tmp - vi->maxout_total);
9940 if (is_lo < 0) is_lo = 0;
9941 }
9942
9943 else
9944 is_lo = 0;
9945
9946 tmp = ((id >> 8) + .5)/255;
9947
9948 if (tmp < 1)
9949 {
9950 is_hi = floor(outmax * tmp + vi->maxout_total);
9951 if (is_hi > outmax) is_hi = outmax;
9952 }
9953
9954 else
9955 is_hi = outmax;
9956
9957 if (!(od < is_lo || od > is_hi))
9958 {
9959 if (encoded_error < vi->outlog)
9960 return i;
9961
9962 pass = "within 8 bit limits:\n";
9963 }
9964 }
9965 # endif
9966 # endif
9967 }
9968 else /* !use_input_precision */
9969 is_lo = es_lo, is_hi = es_hi;
9970
9971 /* Attempt to output a meaningful error/warning message: the message
9972 * output depends on the background/composite operation being performed
9973 * because this changes what parameters were actually used above.
9974 */
9975 {
9976 size_t pos = 0;
9977 /* Need either 1/255 or 1/65535 precision here; 3 or 6 decimal
9978 * places. Just use outmax to work out which.
9979 */
9980 int precision = (outmax >= 1000 ? 6 : 3);
9981 int use_input=1, use_background=0, do_compose=0;
9982 char msg[256];
9983
9984 if (pass != 0)
9985 pos = safecat(msg, sizeof msg, pos, "\n\t");
9986
9987 /* Set up the various flags, the output_is_encoded flag above
9988 * is also used below. do_compose is just a double check.
9989 */
9990 switch (do_background)
9991 {
9992 # ifdef PNG_READ_BACKGROUND_SUPPORTED
9993 case PNG_BACKGROUND_GAMMA_SCREEN:
9994 case PNG_BACKGROUND_GAMMA_FILE:
9995 case PNG_BACKGROUND_GAMMA_UNIQUE:
9996 use_background = (alpha >= 0 && alpha < 1);
9997 /*FALL THROUGH*/
9998 # endif
9999 # ifdef PNG_READ_ALPHA_MODE_SUPPORTED
10000 case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
10001 case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
10002 case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
10003 # endif /* ALPHA_MODE_SUPPORTED */
10004 do_compose = (alpha > 0 && alpha < 1);
10005 use_input = (alpha != 0);
10006 break;
10007
10008 default:
10009 break;
10010 }
10011
10012 /* Check the 'compose' flag */
10013 if (compose != do_compose)
10014 png_error(vi->pp, "internal error (compose)");
10015
10016 /* 'name' is the component name */
10017 pos = safecat(msg, sizeof msg, pos, name);
10018 pos = safecat(msg, sizeof msg, pos, "(");
10019 pos = safecatn(msg, sizeof msg, pos, id);
10020 if (use_input || pass != 0/*logging*/)
10021 {
10022 if (isbit != id)
10023 {
10024 /* sBIT has reduced the precision of the input: */
10025 pos = safecat(msg, sizeof msg, pos, ", sbit(");
10026 pos = safecatn(msg, sizeof msg, pos, vi->sbit);
10027 pos = safecat(msg, sizeof msg, pos, "): ");
10028 pos = safecatn(msg, sizeof msg, pos, isbit);
10029 }
10030 pos = safecat(msg, sizeof msg, pos, "/");
10031 /* The output is either "id/max" or "id sbit(sbit): isbit/max" */
10032 pos = safecatn(msg, sizeof msg, pos, vi->sbit_max);
10033 }
10034 pos = safecat(msg, sizeof msg, pos, ")");
10035
10036 /* A component may have been multiplied (in linear space) by the
10037 * alpha value, 'compose' says whether this is relevant.
10038 */
10039 if (compose || pass != 0)
10040 {
10041 /* If any form of composition is being done report our
10042 * calculated linear value here (the code above doesn't record
10043 * the input value before composition is performed, so what
10044 * gets reported is the value after composition.)
10045 */
10046 if (use_input || pass != 0)
10047 {
10048 if (vi->file_inverse > 0)
10049 {
10050 pos = safecat(msg, sizeof msg, pos, "^");
10051 pos = safecatd(msg, sizeof msg, pos, vi->file_inverse, 2);
10052 }
10053
10054 else
10055 pos = safecat(msg, sizeof msg, pos, "[linear]");
10056
10057 pos = safecat(msg, sizeof msg, pos, "*(alpha)");
10058 pos = safecatd(msg, sizeof msg, pos, alpha, precision);
10059 }
10060
10061 /* Now record the *linear* background value if it was used
10062 * (this function is not passed the original, non-linear,
10063 * value but it is contained in the test name.)
10064 */
10065 if (use_background)
10066 {
10067 pos = safecat(msg, sizeof msg, pos, use_input ? "+" : " ");
10068 pos = safecat(msg, sizeof msg, pos, "(background)");
10069 pos = safecatd(msg, sizeof msg, pos, background, precision);
10070 pos = safecat(msg, sizeof msg, pos, "*");
10071 pos = safecatd(msg, sizeof msg, pos, 1-alpha, precision);
10072 }
10073 }
10074
10075 /* Report the calculated value (input_sample) and the linearized
10076 * libpng value (output) unless this is just a component gamma
10077 * correction.
10078 */
10079 if (compose || alpha < 0 || pass != 0)
10080 {
10081 pos = safecat(msg, sizeof msg, pos,
10082 pass != 0 ? " =\n\t" : " = ");
10083 pos = safecatd(msg, sizeof msg, pos, input_sample, precision);
10084 pos = safecat(msg, sizeof msg, pos, " (libpng: ");
10085 pos = safecatd(msg, sizeof msg, pos, output, precision);
10086 pos = safecat(msg, sizeof msg, pos, ")");
10087
10088 /* Finally report the output gamma encoding, if any. */
10089 if (output_is_encoded)
10090 {
10091 pos = safecat(msg, sizeof msg, pos, " ^");
10092 pos = safecatd(msg, sizeof msg, pos, vi->screen_inverse, 2);
10093 pos = safecat(msg, sizeof msg, pos, "(to screen) =");
10094 }
10095
10096 else
10097 pos = safecat(msg, sizeof msg, pos, " [screen is linear] =");
10098 }
10099
10100 if ((!compose && alpha >= 0) || pass != 0)
10101 {
10102 if (pass != 0) /* logging */
10103 pos = safecat(msg, sizeof msg, pos, "\n\t[overall:");
10104
10105 /* This is the non-composition case, the internal linear
10106 * values are irrelevant (though the log below will reveal
10107 * them.) Output a much shorter warning/error message and report
10108 * the overall gamma correction.
10109 */
10110 if (vi->gamma_correction > 0)
10111 {
10112 pos = safecat(msg, sizeof msg, pos, " ^");
10113 pos = safecatd(msg, sizeof msg, pos, vi->gamma_correction, 2);
10114 pos = safecat(msg, sizeof msg, pos, "(gamma correction) =");
10115 }
10116
10117 else
10118 pos = safecat(msg, sizeof msg, pos,
10119 " [no gamma correction] =");
10120
10121 if (pass != 0)
10122 pos = safecat(msg, sizeof msg, pos, "]");
10123 }
10124
10125 /* This is our calculated encoded_sample which should (but does
10126 * not) match od:
10127 */
10128 pos = safecat(msg, sizeof msg, pos, pass != 0 ? "\n\t" : " ");
10129 pos = safecatd(msg, sizeof msg, pos, is_lo, 1);
10130 pos = safecat(msg, sizeof msg, pos, " < ");
10131 pos = safecatd(msg, sizeof msg, pos, encoded_sample, 1);
10132 pos = safecat(msg, sizeof msg, pos, " (libpng: ");
10133 pos = safecatn(msg, sizeof msg, pos, od);
10134 pos = safecat(msg, sizeof msg, pos, ")");
10135 pos = safecat(msg, sizeof msg, pos, "/");
10136 pos = safecatn(msg, sizeof msg, pos, outmax);
10137 pos = safecat(msg, sizeof msg, pos, " < ");
10138 pos = safecatd(msg, sizeof msg, pos, is_hi, 1);
10139
10140 if (pass == 0) /* The error condition */
10141 {
10142 # ifdef PNG_WARNINGS_SUPPORTED
10143 png_warning(vi->pp, msg);
10144 # else
10145 store_warning(vi->pp, msg);
10146 # endif
10147 }
10148
10149 else /* logging this value */
10150 store_verbose(&vi->dp->pm->this, vi->pp, pass, msg);
10151 }
10152 }
10153 }
10154
10155 return i;
10156 }
10157
10158 static void
gamma_image_validate(gamma_display * dp,png_const_structp pp,png_infop pi)10159 gamma_image_validate(gamma_display *dp, png_const_structp pp,
10160 png_infop pi)
10161 {
10162 /* Get some constants derived from the input and output file formats: */
10163 const png_store* const ps = dp->this.ps;
10164 const png_byte in_ct = dp->this.colour_type;
10165 const png_byte in_bd = dp->this.bit_depth;
10166 const png_uint_32 w = dp->this.w;
10167 const png_uint_32 h = dp->this.h;
10168 const size_t cbRow = dp->this.cbRow;
10169 const png_byte out_ct = png_get_color_type(pp, pi);
10170 const png_byte out_bd = png_get_bit_depth(pp, pi);
10171
10172 /* There are three sources of error, firstly the quantization in the
10173 * file encoding, determined by sbit and/or the file depth, secondly
10174 * the output (screen) gamma and thirdly the output file encoding.
10175 *
10176 * Since this API receives the screen and file gamma in double
10177 * precision it is possible to calculate an exact answer given an input
10178 * pixel value. Therefore we assume that the *input* value is exact -
10179 * sample/maxsample - calculate the corresponding gamma corrected
10180 * output to the limits of double precision arithmetic and compare with
10181 * what libpng returns.
10182 *
10183 * Since the library must quantize the output to 8 or 16 bits there is
10184 * a fundamental limit on the accuracy of the output of +/-.5 - this
10185 * quantization limit is included in addition to the other limits
10186 * specified by the paramaters to the API. (Effectively, add .5
10187 * everywhere.)
10188 *
10189 * The behavior of the 'sbit' paramter is defined by section 12.5
10190 * (sample depth scaling) of the PNG spec. That section forces the
10191 * decoder to assume that the PNG values have been scaled if sBIT is
10192 * present:
10193 *
10194 * png-sample = floor( input-sample * (max-out/max-in) + .5);
10195 *
10196 * This means that only a subset of the possible PNG values should
10197 * appear in the input. However, the spec allows the encoder to use a
10198 * variety of approximations to the above and doesn't require any
10199 * restriction of the values produced.
10200 *
10201 * Nevertheless the spec requires that the upper 'sBIT' bits of the
10202 * value stored in a PNG file be the original sample bits.
10203 * Consequently the code below simply scales the top sbit bits by
10204 * (1<<sbit)-1 to obtain an original sample value.
10205 *
10206 * Because there is limited precision in the input it is arguable that
10207 * an acceptable result is any valid result from input-.5 to input+.5.
10208 * The basic tests below do not do this, however if 'use_input_precision'
10209 * is set a subsequent test is performed above.
10210 */
10211 const unsigned int samples_per_pixel = (out_ct & 2U) ? 3U : 1U;
10212 int processing;
10213 png_uint_32 y;
10214 const store_palette_entry *in_palette = dp->this.palette;
10215 const int in_is_transparent = dp->this.is_transparent;
10216 int process_tRNS;
10217 int out_npalette = -1;
10218 int out_is_transparent = 0; /* Just refers to the palette case */
10219 store_palette out_palette;
10220 validate_info vi;
10221
10222 /* Check for row overwrite errors */
10223 store_image_check(dp->this.ps, pp, 0);
10224
10225 /* Supply the input and output sample depths here - 8 for an indexed image,
10226 * otherwise the bit depth.
10227 */
10228 init_validate_info(&vi, dp, pp, in_ct==3?8:in_bd, out_ct==3?8:out_bd);
10229
10230 processing = (vi.gamma_correction > 0 && !dp->threshold_test)
10231 || in_bd != out_bd || in_ct != out_ct || vi.do_background;
10232 process_tRNS = dp->this.has_tRNS && vi.do_background;
10233
10234 /* TODO: FIX THIS: MAJOR BUG! If the transformations all happen inside
10235 * the palette there is no way of finding out, because libpng fails to
10236 * update the palette on png_read_update_info. Indeed, libpng doesn't
10237 * even do the required work until much later, when it doesn't have any
10238 * info pointer. Oops. For the moment 'processing' is turned off if
10239 * out_ct is palette.
10240 */
10241 if (in_ct == 3 && out_ct == 3)
10242 processing = 0;
10243
10244 if (processing && out_ct == 3)
10245 out_is_transparent = read_palette(out_palette, &out_npalette, pp, pi);
10246
10247 for (y=0; y<h; ++y)
10248 {
10249 png_const_bytep pRow = store_image_row(ps, pp, 0, y);
10250 png_byte std[STANDARD_ROWMAX];
10251
10252 transform_row(pp, std, in_ct, in_bd, y);
10253
10254 if (processing)
10255 {
10256 unsigned int x;
10257
10258 for (x=0; x<w; ++x)
10259 {
10260 double alpha = 1; /* serves as a flag value */
10261
10262 /* Record the palette index for index images. */
10263 const unsigned int in_index =
10264 in_ct == 3 ? sample(std, 3, in_bd, x, 0, 0, 0) : 256;
10265 const unsigned int out_index =
10266 out_ct == 3 ? sample(std, 3, out_bd, x, 0, 0, 0) : 256;
10267
10268 /* Handle input alpha - png_set_background will cause the output
10269 * alpha to disappear so there is nothing to check.
10270 */
10271 if ((in_ct & PNG_COLOR_MASK_ALPHA) != 0 ||
10272 (in_ct == 3 && in_is_transparent))
10273 {
10274 const unsigned int input_alpha = in_ct == 3 ?
10275 dp->this.palette[in_index].alpha :
10276 sample(std, in_ct, in_bd, x, samples_per_pixel, 0, 0);
10277
10278 unsigned int output_alpha = 65536 /* as a flag value */;
10279
10280 if (out_ct == 3)
10281 {
10282 if (out_is_transparent)
10283 output_alpha = out_palette[out_index].alpha;
10284 }
10285
10286 else if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0)
10287 output_alpha = sample(pRow, out_ct, out_bd, x,
10288 samples_per_pixel, 0, 0);
10289
10290 if (output_alpha != 65536)
10291 alpha = gamma_component_validate("alpha", &vi, input_alpha,
10292 output_alpha, -1/*alpha*/, 0/*background*/);
10293
10294 else /* no alpha in output */
10295 {
10296 /* This is a copy of the calculation of 'i' above in order to
10297 * have the alpha value to use in the background calculation.
10298 */
10299 alpha = input_alpha >> vi.isbit_shift;
10300 alpha /= vi.sbit_max;
10301 }
10302 }
10303
10304 else if (process_tRNS)
10305 {
10306 /* alpha needs to be set appropriately for this pixel, it is
10307 * currently 1 and needs to be 0 for an input pixel which matches
10308 * the values in tRNS.
10309 */
10310 switch (in_ct)
10311 {
10312 case 0: /* gray */
10313 if (sample(std, in_ct, in_bd, x, 0, 0, 0) ==
10314 dp->this.transparent.red)
10315 alpha = 0;
10316 break;
10317
10318 case 2: /* RGB */
10319 if (sample(std, in_ct, in_bd, x, 0, 0, 0) ==
10320 dp->this.transparent.red &&
10321 sample(std, in_ct, in_bd, x, 1, 0, 0) ==
10322 dp->this.transparent.green &&
10323 sample(std, in_ct, in_bd, x, 2, 0, 0) ==
10324 dp->this.transparent.blue)
10325 alpha = 0;
10326 break;
10327
10328 default:
10329 break;
10330 }
10331 }
10332
10333 /* Handle grayscale or RGB components. */
10334 if ((in_ct & PNG_COLOR_MASK_COLOR) == 0) /* grayscale */
10335 (void)gamma_component_validate("gray", &vi,
10336 sample(std, in_ct, in_bd, x, 0, 0, 0),
10337 sample(pRow, out_ct, out_bd, x, 0, 0, 0),
10338 alpha/*component*/, vi.background_red);
10339 else /* RGB or palette */
10340 {
10341 (void)gamma_component_validate("red", &vi,
10342 in_ct == 3 ? in_palette[in_index].red :
10343 sample(std, in_ct, in_bd, x, 0, 0, 0),
10344 out_ct == 3 ? out_palette[out_index].red :
10345 sample(pRow, out_ct, out_bd, x, 0, 0, 0),
10346 alpha/*component*/, vi.background_red);
10347
10348 (void)gamma_component_validate("green", &vi,
10349 in_ct == 3 ? in_palette[in_index].green :
10350 sample(std, in_ct, in_bd, x, 1, 0, 0),
10351 out_ct == 3 ? out_palette[out_index].green :
10352 sample(pRow, out_ct, out_bd, x, 1, 0, 0),
10353 alpha/*component*/, vi.background_green);
10354
10355 (void)gamma_component_validate("blue", &vi,
10356 in_ct == 3 ? in_palette[in_index].blue :
10357 sample(std, in_ct, in_bd, x, 2, 0, 0),
10358 out_ct == 3 ? out_palette[out_index].blue :
10359 sample(pRow, out_ct, out_bd, x, 2, 0, 0),
10360 alpha/*component*/, vi.background_blue);
10361 }
10362 }
10363 }
10364
10365 else if (memcmp(std, pRow, cbRow) != 0)
10366 {
10367 char msg[64];
10368
10369 /* No transform is expected on the threshold tests. */
10370 sprintf(msg, "gamma: below threshold row %lu changed",
10371 (unsigned long)y);
10372
10373 png_error(pp, msg);
10374 }
10375 } /* row (y) loop */
10376
10377 dp->this.ps->validated = 1;
10378 }
10379
10380 static void PNGCBAPI
gamma_end(png_structp ppIn,png_infop pi)10381 gamma_end(png_structp ppIn, png_infop pi)
10382 {
10383 png_const_structp pp = ppIn;
10384 gamma_display *dp = voidcast(gamma_display*, png_get_progressive_ptr(pp));
10385
10386 if (!dp->this.speed)
10387 gamma_image_validate(dp, pp, pi);
10388 else
10389 dp->this.ps->validated = 1;
10390 }
10391
10392 /* A single test run checking a gamma transformation.
10393 *
10394 * maxabs: maximum absolute error as a fraction
10395 * maxout: maximum output error in the output units
10396 * maxpc: maximum percentage error (as a percentage)
10397 */
10398 static void
gamma_test(png_modifier * pmIn,const png_byte colour_typeIn,const png_byte bit_depthIn,const int palette_numberIn,const int interlace_typeIn,const double file_gammaIn,const double screen_gammaIn,const png_byte sbitIn,const int threshold_testIn,const char * name,const int use_input_precisionIn,const int scale16In,const int expand16In,const int do_backgroundIn,const png_color_16 * bkgd_colorIn,double bkgd_gammaIn)10399 gamma_test(png_modifier *pmIn, const png_byte colour_typeIn,
10400 const png_byte bit_depthIn, const int palette_numberIn,
10401 const int interlace_typeIn,
10402 const double file_gammaIn, const double screen_gammaIn,
10403 const png_byte sbitIn, const int threshold_testIn,
10404 const char *name,
10405 const int use_input_precisionIn, const int scale16In,
10406 const int expand16In, const int do_backgroundIn,
10407 const png_color_16 *bkgd_colorIn, double bkgd_gammaIn)
10408 {
10409 gamma_display d;
10410 context(&pmIn->this, fault);
10411
10412 gamma_display_init(&d, pmIn, FILEID(colour_typeIn, bit_depthIn,
10413 palette_numberIn, interlace_typeIn, 0, 0, 0),
10414 file_gammaIn, screen_gammaIn, sbitIn,
10415 threshold_testIn, use_input_precisionIn, scale16In,
10416 expand16In, do_backgroundIn, bkgd_colorIn, bkgd_gammaIn);
10417
10418 Try
10419 {
10420 png_structp pp;
10421 png_infop pi;
10422 gama_modification gama_mod;
10423 srgb_modification srgb_mod;
10424 sbit_modification sbit_mod;
10425
10426 /* For the moment don't use the png_modifier support here. */
10427 d.pm->encoding_counter = 0;
10428 modifier_set_encoding(d.pm); /* Just resets everything */
10429 d.pm->current_gamma = d.file_gamma;
10430
10431 /* Make an appropriate modifier to set the PNG file gamma to the
10432 * given gamma value and the sBIT chunk to the given precision.
10433 */
10434 d.pm->modifications = NULL;
10435 gama_modification_init(&gama_mod, d.pm, d.file_gamma);
10436 srgb_modification_init(&srgb_mod, d.pm, 127 /*delete*/);
10437 if (d.sbit > 0)
10438 sbit_modification_init(&sbit_mod, d.pm, d.sbit);
10439
10440 modification_reset(d.pm->modifications);
10441
10442 /* Get a png_struct for reading the image. */
10443 pp = set_modifier_for_read(d.pm, &pi, d.this.id, name);
10444 standard_palette_init(&d.this);
10445
10446 /* Introduce the correct read function. */
10447 if (d.pm->this.progressive)
10448 {
10449 /* Share the row function with the standard implementation. */
10450 png_set_progressive_read_fn(pp, &d, gamma_info, progressive_row,
10451 gamma_end);
10452
10453 /* Now feed data into the reader until we reach the end: */
10454 modifier_progressive_read(d.pm, pp, pi);
10455 }
10456 else
10457 {
10458 /* modifier_read expects a png_modifier* */
10459 png_set_read_fn(pp, d.pm, modifier_read);
10460
10461 /* Check the header values: */
10462 png_read_info(pp, pi);
10463
10464 /* Process the 'info' requirements. Only one image is generated */
10465 gamma_info_imp(&d, pp, pi);
10466
10467 sequential_row(&d.this, pp, pi, -1, 0);
10468
10469 if (!d.this.speed)
10470 gamma_image_validate(&d, pp, pi);
10471 else
10472 d.this.ps->validated = 1;
10473 }
10474
10475 modifier_reset(d.pm);
10476
10477 if (d.pm->log && !d.threshold_test && !d.this.speed)
10478 fprintf(stderr, "%d bit %s %s: max error %f (%.2g, %2g%%)\n",
10479 d.this.bit_depth, colour_types[d.this.colour_type], name,
10480 d.maxerrout, d.maxerrabs, 100*d.maxerrpc);
10481
10482 /* Log the summary values too. */
10483 if (d.this.colour_type == 0 || d.this.colour_type == 4)
10484 {
10485 switch (d.this.bit_depth)
10486 {
10487 case 1:
10488 break;
10489
10490 case 2:
10491 if (d.maxerrout > d.pm->error_gray_2)
10492 d.pm->error_gray_2 = d.maxerrout;
10493
10494 break;
10495
10496 case 4:
10497 if (d.maxerrout > d.pm->error_gray_4)
10498 d.pm->error_gray_4 = d.maxerrout;
10499
10500 break;
10501
10502 case 8:
10503 if (d.maxerrout > d.pm->error_gray_8)
10504 d.pm->error_gray_8 = d.maxerrout;
10505
10506 break;
10507
10508 case 16:
10509 if (d.maxerrout > d.pm->error_gray_16)
10510 d.pm->error_gray_16 = d.maxerrout;
10511
10512 break;
10513
10514 default:
10515 png_error(pp, "bad bit depth (internal: 1)");
10516 }
10517 }
10518
10519 else if (d.this.colour_type == 2 || d.this.colour_type == 6)
10520 {
10521 switch (d.this.bit_depth)
10522 {
10523 case 8:
10524
10525 if (d.maxerrout > d.pm->error_color_8)
10526 d.pm->error_color_8 = d.maxerrout;
10527
10528 break;
10529
10530 case 16:
10531
10532 if (d.maxerrout > d.pm->error_color_16)
10533 d.pm->error_color_16 = d.maxerrout;
10534
10535 break;
10536
10537 default:
10538 png_error(pp, "bad bit depth (internal: 2)");
10539 }
10540 }
10541
10542 else if (d.this.colour_type == 3)
10543 {
10544 if (d.maxerrout > d.pm->error_indexed)
10545 d.pm->error_indexed = d.maxerrout;
10546 }
10547 }
10548
10549 Catch(fault)
10550 modifier_reset(voidcast(png_modifier*,(void*)fault));
10551 }
10552
gamma_threshold_test(png_modifier * pm,png_byte colour_type,png_byte bit_depth,int interlace_type,double file_gamma,double screen_gamma)10553 static void gamma_threshold_test(png_modifier *pm, png_byte colour_type,
10554 png_byte bit_depth, int interlace_type, double file_gamma,
10555 double screen_gamma)
10556 {
10557 size_t pos = 0;
10558 char name[64];
10559 pos = safecat(name, sizeof name, pos, "threshold ");
10560 pos = safecatd(name, sizeof name, pos, file_gamma, 3);
10561 pos = safecat(name, sizeof name, pos, "/");
10562 pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
10563
10564 (void)gamma_test(pm, colour_type, bit_depth, 0/*palette*/, interlace_type,
10565 file_gamma, screen_gamma, 0/*sBIT*/, 1/*threshold test*/, name,
10566 0 /*no input precision*/,
10567 0 /*no scale16*/, 0 /*no expand16*/, 0 /*no background*/, 0 /*hence*/,
10568 0 /*no background gamma*/);
10569 }
10570
10571 static void
perform_gamma_threshold_tests(png_modifier * pm)10572 perform_gamma_threshold_tests(png_modifier *pm)
10573 {
10574 png_byte colour_type = 0;
10575 png_byte bit_depth = 0;
10576 unsigned int palette_number = 0;
10577
10578 /* Don't test more than one instance of each palette - it's pointless, in
10579 * fact this test is somewhat excessive since libpng doesn't make this
10580 * decision based on colour type or bit depth!
10581 *
10582 * CHANGED: now test two palettes and, as a side effect, images with and
10583 * without tRNS.
10584 */
10585 while (next_format(&colour_type, &bit_depth, &palette_number,
10586 pm->test_lbg_gamma_threshold, pm->test_tRNS))
10587 if (palette_number < 2)
10588 {
10589 double test_gamma = 1.0;
10590 while (test_gamma >= .4)
10591 {
10592 /* There's little point testing the interlacing vs non-interlacing,
10593 * but this can be set from the command line.
10594 */
10595 gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
10596 test_gamma, 1/test_gamma);
10597 test_gamma *= .95;
10598 }
10599
10600 /* And a special test for sRGB */
10601 gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
10602 .45455, 2.2);
10603
10604 if (fail(pm))
10605 return;
10606 }
10607 }
10608
gamma_transform_test(png_modifier * pm,const png_byte colour_type,const png_byte bit_depth,const int palette_number,const int interlace_type,const double file_gamma,const double screen_gamma,const png_byte sbit,const int use_input_precision,const int scale16)10609 static void gamma_transform_test(png_modifier *pm,
10610 const png_byte colour_type, const png_byte bit_depth,
10611 const int palette_number,
10612 const int interlace_type, const double file_gamma,
10613 const double screen_gamma, const png_byte sbit,
10614 const int use_input_precision, const int scale16)
10615 {
10616 size_t pos = 0;
10617 char name[64];
10618
10619 if (sbit != bit_depth && sbit != 0)
10620 {
10621 pos = safecat(name, sizeof name, pos, "sbit(");
10622 pos = safecatn(name, sizeof name, pos, sbit);
10623 pos = safecat(name, sizeof name, pos, ") ");
10624 }
10625
10626 else
10627 pos = safecat(name, sizeof name, pos, "gamma ");
10628
10629 if (scale16)
10630 pos = safecat(name, sizeof name, pos, "16to8 ");
10631
10632 pos = safecatd(name, sizeof name, pos, file_gamma, 3);
10633 pos = safecat(name, sizeof name, pos, "->");
10634 pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
10635
10636 gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
10637 file_gamma, screen_gamma, sbit, 0, name, use_input_precision,
10638 scale16, pm->test_gamma_expand16, 0 , 0, 0);
10639 }
10640
perform_gamma_transform_tests(png_modifier * pm)10641 static void perform_gamma_transform_tests(png_modifier *pm)
10642 {
10643 png_byte colour_type = 0;
10644 png_byte bit_depth = 0;
10645 unsigned int palette_number = 0;
10646
10647 while (next_format(&colour_type, &bit_depth, &palette_number,
10648 pm->test_lbg_gamma_transform, pm->test_tRNS))
10649 {
10650 unsigned int i, j;
10651
10652 for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
10653 if (i != j)
10654 {
10655 gamma_transform_test(pm, colour_type, bit_depth, palette_number,
10656 pm->interlace_type, 1/pm->gammas[i], pm->gammas[j], 0/*sBIT*/,
10657 pm->use_input_precision, 0 /*do not scale16*/);
10658
10659 if (fail(pm))
10660 return;
10661 }
10662 }
10663 }
10664
perform_gamma_sbit_tests(png_modifier * pm)10665 static void perform_gamma_sbit_tests(png_modifier *pm)
10666 {
10667 png_byte sbit;
10668
10669 /* The only interesting cases are colour and grayscale, alpha is ignored here
10670 * for overall speed. Only bit depths where sbit is less than the bit depth
10671 * are tested.
10672 */
10673 for (sbit=pm->sbitlow; sbit<(1<<READ_BDHI); ++sbit)
10674 {
10675 png_byte colour_type = 0, bit_depth = 0;
10676 unsigned int npalette = 0;
10677
10678 while (next_format(&colour_type, &bit_depth, &npalette,
10679 pm->test_lbg_gamma_sbit, pm->test_tRNS))
10680 if ((colour_type & PNG_COLOR_MASK_ALPHA) == 0 &&
10681 ((colour_type == 3 && sbit < 8) ||
10682 (colour_type != 3 && sbit < bit_depth)))
10683 {
10684 unsigned int i;
10685
10686 for (i=0; i<pm->ngamma_tests; ++i)
10687 {
10688 unsigned int j;
10689
10690 for (j=0; j<pm->ngamma_tests; ++j) if (i != j)
10691 {
10692 gamma_transform_test(pm, colour_type, bit_depth, npalette,
10693 pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
10694 sbit, pm->use_input_precision_sbit, 0 /*scale16*/);
10695
10696 if (fail(pm))
10697 return;
10698 }
10699 }
10700 }
10701 }
10702 }
10703
10704 /* Note that this requires a 16 bit source image but produces 8 bit output, so
10705 * we only need the 16bit write support, but the 16 bit images are only
10706 * generated if DO_16BIT is defined.
10707 */
10708 #ifdef DO_16BIT
perform_gamma_scale16_tests(png_modifier * pm)10709 static void perform_gamma_scale16_tests(png_modifier *pm)
10710 {
10711 # ifndef PNG_MAX_GAMMA_8
10712 # define PNG_MAX_GAMMA_8 11
10713 # endif
10714 # if defined PNG_MAX_GAMMA_8 || PNG_LIBPNG_VER < 10700
10715 # define SBIT_16_TO_8 PNG_MAX_GAMMA_8
10716 # else
10717 # define SBIT_16_TO_8 16
10718 # endif
10719 /* Include the alpha cases here. Note that sbit matches the internal value
10720 * used by the library - otherwise we will get spurious errors from the
10721 * internal sbit style approximation.
10722 *
10723 * The threshold test is here because otherwise the 16 to 8 conversion will
10724 * proceed *without* gamma correction, and the tests above will fail (but not
10725 * by much) - this could be fixed, it only appears with the -g option.
10726 */
10727 unsigned int i, j;
10728 for (i=0; i<pm->ngamma_tests; ++i)
10729 {
10730 for (j=0; j<pm->ngamma_tests; ++j)
10731 {
10732 if (i != j &&
10733 fabs(pm->gammas[j]/pm->gammas[i]-1) >= PNG_GAMMA_THRESHOLD)
10734 {
10735 gamma_transform_test(pm, 0, 16, 0, pm->interlace_type,
10736 1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
10737 pm->use_input_precision_16to8, 1 /*scale16*/);
10738
10739 if (fail(pm))
10740 return;
10741
10742 gamma_transform_test(pm, 2, 16, 0, pm->interlace_type,
10743 1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
10744 pm->use_input_precision_16to8, 1 /*scale16*/);
10745
10746 if (fail(pm))
10747 return;
10748
10749 gamma_transform_test(pm, 4, 16, 0, pm->interlace_type,
10750 1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
10751 pm->use_input_precision_16to8, 1 /*scale16*/);
10752
10753 if (fail(pm))
10754 return;
10755
10756 gamma_transform_test(pm, 6, 16, 0, pm->interlace_type,
10757 1/pm->gammas[i], pm->gammas[j], SBIT_16_TO_8,
10758 pm->use_input_precision_16to8, 1 /*scale16*/);
10759
10760 if (fail(pm))
10761 return;
10762 }
10763 }
10764 }
10765 }
10766 #endif /* 16 to 8 bit conversion */
10767
10768 #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
10769 defined(PNG_READ_ALPHA_MODE_SUPPORTED)
gamma_composition_test(png_modifier * pm,const png_byte colour_type,const png_byte bit_depth,const int palette_number,const int interlace_type,const double file_gamma,const double screen_gamma,const int use_input_precision,const int do_background,const int expand_16)10770 static void gamma_composition_test(png_modifier *pm,
10771 const png_byte colour_type, const png_byte bit_depth,
10772 const int palette_number,
10773 const int interlace_type, const double file_gamma,
10774 const double screen_gamma,
10775 const int use_input_precision, const int do_background,
10776 const int expand_16)
10777 {
10778 size_t pos = 0;
10779 png_const_charp base;
10780 double bg;
10781 char name[128];
10782 png_color_16 background;
10783
10784 /* Make up a name and get an appropriate background gamma value. */
10785 switch (do_background)
10786 {
10787 default:
10788 base = "";
10789 bg = 4; /* should not be used */
10790 break;
10791 case PNG_BACKGROUND_GAMMA_SCREEN:
10792 base = " bckg(Screen):";
10793 bg = 1/screen_gamma;
10794 break;
10795 case PNG_BACKGROUND_GAMMA_FILE:
10796 base = " bckg(File):";
10797 bg = file_gamma;
10798 break;
10799 case PNG_BACKGROUND_GAMMA_UNIQUE:
10800 base = " bckg(Unique):";
10801 /* This tests the handling of a unique value, the math is such that the
10802 * value tends to be <1, but is neither screen nor file (even if they
10803 * match!)
10804 */
10805 bg = (file_gamma + screen_gamma) / 3;
10806 break;
10807 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
10808 case ALPHA_MODE_OFFSET + PNG_ALPHA_PNG:
10809 base = " alpha(PNG)";
10810 bg = 4; /* should not be used */
10811 break;
10812 case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
10813 base = " alpha(Porter-Duff)";
10814 bg = 4; /* should not be used */
10815 break;
10816 case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
10817 base = " alpha(Optimized)";
10818 bg = 4; /* should not be used */
10819 break;
10820 case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
10821 base = " alpha(Broken)";
10822 bg = 4; /* should not be used */
10823 break;
10824 #endif
10825 }
10826
10827 /* Use random background values - the background is always presented in the
10828 * output space (8 or 16 bit components).
10829 */
10830 if (expand_16 || bit_depth == 16)
10831 {
10832 png_uint_32 r = random_32();
10833
10834 background.red = (png_uint_16)r;
10835 background.green = (png_uint_16)(r >> 16);
10836 r = random_32();
10837 background.blue = (png_uint_16)r;
10838 background.gray = (png_uint_16)(r >> 16);
10839
10840 /* In earlier libpng versions, those where DIGITIZE is set, any background
10841 * gamma correction in the expand16 case was done using 8-bit gamma
10842 * correction tables, resulting in larger errors. To cope with those
10843 * cases use a 16-bit background value which will handle this gamma
10844 * correction.
10845 */
10846 # if DIGITIZE
10847 if (expand_16 && (do_background == PNG_BACKGROUND_GAMMA_UNIQUE ||
10848 do_background == PNG_BACKGROUND_GAMMA_FILE) &&
10849 fabs(bg*screen_gamma-1) > PNG_GAMMA_THRESHOLD)
10850 {
10851 /* The background values will be looked up in an 8-bit table to do
10852 * the gamma correction, so only select values which are an exact
10853 * match for the 8-bit table entries:
10854 */
10855 background.red = (png_uint_16)((background.red >> 8) * 257);
10856 background.green = (png_uint_16)((background.green >> 8) * 257);
10857 background.blue = (png_uint_16)((background.blue >> 8) * 257);
10858 background.gray = (png_uint_16)((background.gray >> 8) * 257);
10859 }
10860 # endif
10861 }
10862
10863 else /* 8 bit colors */
10864 {
10865 png_uint_32 r = random_32();
10866
10867 background.red = (png_byte)r;
10868 background.green = (png_byte)(r >> 8);
10869 background.blue = (png_byte)(r >> 16);
10870 background.gray = (png_byte)(r >> 24);
10871 }
10872
10873 background.index = 193; /* rgb(193,193,193) to detect errors */
10874
10875 if (!(colour_type & PNG_COLOR_MASK_COLOR))
10876 {
10877 /* Because, currently, png_set_background is always called with
10878 * 'need_expand' false in this case and because the gamma test itself
10879 * doesn't cause an expand to 8-bit for lower bit depths the colour must
10880 * be reduced to the correct range.
10881 */
10882 if (bit_depth < 8)
10883 background.gray &= (png_uint_16)((1U << bit_depth)-1);
10884
10885 /* Grayscale input, we do not convert to RGB (TBD), so we must set the
10886 * background to gray - else libpng seems to fail.
10887 */
10888 background.red = background.green = background.blue = background.gray;
10889 }
10890
10891 pos = safecat(name, sizeof name, pos, "gamma ");
10892 pos = safecatd(name, sizeof name, pos, file_gamma, 3);
10893 pos = safecat(name, sizeof name, pos, "->");
10894 pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
10895
10896 pos = safecat(name, sizeof name, pos, base);
10897 if (do_background < ALPHA_MODE_OFFSET)
10898 {
10899 /* Include the background color and gamma in the name: */
10900 pos = safecat(name, sizeof name, pos, "(");
10901 /* This assumes no expand gray->rgb - the current code won't handle that!
10902 */
10903 if (colour_type & PNG_COLOR_MASK_COLOR)
10904 {
10905 pos = safecatn(name, sizeof name, pos, background.red);
10906 pos = safecat(name, sizeof name, pos, ",");
10907 pos = safecatn(name, sizeof name, pos, background.green);
10908 pos = safecat(name, sizeof name, pos, ",");
10909 pos = safecatn(name, sizeof name, pos, background.blue);
10910 }
10911 else
10912 pos = safecatn(name, sizeof name, pos, background.gray);
10913 pos = safecat(name, sizeof name, pos, ")^");
10914 pos = safecatd(name, sizeof name, pos, bg, 3);
10915 }
10916
10917 gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
10918 file_gamma, screen_gamma, 0/*sBIT*/, 0, name, use_input_precision,
10919 0/*strip 16*/, expand_16, do_background, &background, bg);
10920 }
10921
10922
10923 static void
perform_gamma_composition_tests(png_modifier * pm,int do_background,int expand_16)10924 perform_gamma_composition_tests(png_modifier *pm, int do_background,
10925 int expand_16)
10926 {
10927 png_byte colour_type = 0;
10928 png_byte bit_depth = 0;
10929 unsigned int palette_number = 0;
10930
10931 /* Skip the non-alpha cases - there is no setting of a transparency colour at
10932 * present.
10933 *
10934 * TODO: incorrect; the palette case sets tRNS and, now RGB and gray do,
10935 * however the palette case fails miserably so is commented out below.
10936 */
10937 while (next_format(&colour_type, &bit_depth, &palette_number,
10938 pm->test_lbg_gamma_composition, pm->test_tRNS))
10939 if ((colour_type & PNG_COLOR_MASK_ALPHA) != 0
10940 #if 0 /* TODO: FIXME */
10941 /*TODO: FIXME: this should work */
10942 || colour_type == 3
10943 #endif
10944 || (colour_type != 3 && palette_number != 0))
10945 {
10946 unsigned int i, j;
10947
10948 /* Don't skip the i==j case here - it's relevant. */
10949 for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
10950 {
10951 gamma_composition_test(pm, colour_type, bit_depth, palette_number,
10952 pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
10953 pm->use_input_precision, do_background, expand_16);
10954
10955 if (fail(pm))
10956 return;
10957 }
10958 }
10959 }
10960 #endif /* READ_BACKGROUND || READ_ALPHA_MODE */
10961
10962 static void
init_gamma_errors(png_modifier * pm)10963 init_gamma_errors(png_modifier *pm)
10964 {
10965 /* Use -1 to catch tests that were not actually run */
10966 pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = -1.;
10967 pm->error_color_8 = -1.;
10968 pm->error_indexed = -1.;
10969 pm->error_gray_16 = pm->error_color_16 = -1.;
10970 }
10971
10972 static void
print_one(const char * leader,double err)10973 print_one(const char *leader, double err)
10974 {
10975 if (err != -1.)
10976 printf(" %s %.5f\n", leader, err);
10977 }
10978
10979 static void
summarize_gamma_errors(png_modifier * pm,png_const_charp who,int low_bit_depth,int indexed)10980 summarize_gamma_errors(png_modifier *pm, png_const_charp who, int low_bit_depth,
10981 int indexed)
10982 {
10983 fflush(stderr);
10984
10985 if (who)
10986 printf("\nGamma correction with %s:\n", who);
10987
10988 else
10989 printf("\nBasic gamma correction:\n");
10990
10991 if (low_bit_depth)
10992 {
10993 print_one(" 2 bit gray: ", pm->error_gray_2);
10994 print_one(" 4 bit gray: ", pm->error_gray_4);
10995 print_one(" 8 bit gray: ", pm->error_gray_8);
10996 print_one(" 8 bit color:", pm->error_color_8);
10997 if (indexed)
10998 print_one(" indexed: ", pm->error_indexed);
10999 }
11000
11001 print_one("16 bit gray: ", pm->error_gray_16);
11002 print_one("16 bit color:", pm->error_color_16);
11003
11004 fflush(stdout);
11005 }
11006
11007 static void
perform_gamma_test(png_modifier * pm,int summary)11008 perform_gamma_test(png_modifier *pm, int summary)
11009 {
11010 /*TODO: remove this*/
11011 /* Save certain values for the temporary overrides below. */
11012 unsigned int calculations_use_input_precision =
11013 pm->calculations_use_input_precision;
11014 # ifdef PNG_READ_BACKGROUND_SUPPORTED
11015 double maxout8 = pm->maxout8;
11016 # endif
11017
11018 /* First some arbitrary no-transform tests: */
11019 if (!pm->this.speed && pm->test_gamma_threshold)
11020 {
11021 perform_gamma_threshold_tests(pm);
11022
11023 if (fail(pm))
11024 return;
11025 }
11026
11027 /* Now some real transforms. */
11028 if (pm->test_gamma_transform)
11029 {
11030 if (summary)
11031 {
11032 fflush(stderr);
11033 printf("Gamma correction error summary\n\n");
11034 printf("The printed value is the maximum error in the pixel values\n");
11035 printf("calculated by the libpng gamma correction code. The error\n");
11036 printf("is calculated as the difference between the output pixel\n");
11037 printf("value (always an integer) and the ideal value from the\n");
11038 printf("libpng specification (typically not an integer).\n\n");
11039
11040 printf("Expect this value to be less than .5 for 8 bit formats,\n");
11041 printf("less than 1 for formats with fewer than 8 bits and a small\n");
11042 printf("number (typically less than 5) for the 16 bit formats.\n");
11043 printf("For performance reasons the value for 16 bit formats\n");
11044 printf("increases when the image file includes an sBIT chunk.\n");
11045 fflush(stdout);
11046 }
11047
11048 init_gamma_errors(pm);
11049 /*TODO: remove this. Necessary because the current libpng
11050 * implementation works in 8 bits:
11051 */
11052 if (pm->test_gamma_expand16)
11053 pm->calculations_use_input_precision = 1;
11054 perform_gamma_transform_tests(pm);
11055 if (!calculations_use_input_precision)
11056 pm->calculations_use_input_precision = 0;
11057
11058 if (summary)
11059 summarize_gamma_errors(pm, 0/*who*/, 1/*low bit depth*/, 1/*indexed*/);
11060
11061 if (fail(pm))
11062 return;
11063 }
11064
11065 /* The sbit tests produce much larger errors: */
11066 if (pm->test_gamma_sbit)
11067 {
11068 init_gamma_errors(pm);
11069 perform_gamma_sbit_tests(pm);
11070
11071 if (summary)
11072 summarize_gamma_errors(pm, "sBIT", pm->sbitlow < 8U, 1/*indexed*/);
11073
11074 if (fail(pm))
11075 return;
11076 }
11077
11078 #ifdef DO_16BIT /* Should be READ_16BIT_SUPPORTED */
11079 if (pm->test_gamma_scale16)
11080 {
11081 /* The 16 to 8 bit strip operations: */
11082 init_gamma_errors(pm);
11083 perform_gamma_scale16_tests(pm);
11084
11085 if (summary)
11086 {
11087 fflush(stderr);
11088 printf("\nGamma correction with 16 to 8 bit reduction:\n");
11089 printf(" 16 bit gray: %.5f\n", pm->error_gray_16);
11090 printf(" 16 bit color: %.5f\n", pm->error_color_16);
11091 fflush(stdout);
11092 }
11093
11094 if (fail(pm))
11095 return;
11096 }
11097 #endif
11098
11099 #ifdef PNG_READ_BACKGROUND_SUPPORTED
11100 if (pm->test_gamma_background)
11101 {
11102 init_gamma_errors(pm);
11103
11104 /*TODO: remove this. Necessary because the current libpng
11105 * implementation works in 8 bits:
11106 */
11107 if (pm->test_gamma_expand16)
11108 {
11109 pm->calculations_use_input_precision = 1;
11110 pm->maxout8 = .499; /* because the 16 bit background is smashed */
11111 }
11112 perform_gamma_composition_tests(pm, PNG_BACKGROUND_GAMMA_UNIQUE,
11113 pm->test_gamma_expand16);
11114 if (!calculations_use_input_precision)
11115 pm->calculations_use_input_precision = 0;
11116 pm->maxout8 = maxout8;
11117
11118 if (summary)
11119 summarize_gamma_errors(pm, "background", 1, 0/*indexed*/);
11120
11121 if (fail(pm))
11122 return;
11123 }
11124 #endif
11125
11126 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
11127 if (pm->test_gamma_alpha_mode)
11128 {
11129 int do_background;
11130
11131 init_gamma_errors(pm);
11132
11133 /*TODO: remove this. Necessary because the current libpng
11134 * implementation works in 8 bits:
11135 */
11136 if (pm->test_gamma_expand16)
11137 pm->calculations_use_input_precision = 1;
11138 for (do_background = ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD;
11139 do_background <= ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN && !fail(pm);
11140 ++do_background)
11141 perform_gamma_composition_tests(pm, do_background,
11142 pm->test_gamma_expand16);
11143 if (!calculations_use_input_precision)
11144 pm->calculations_use_input_precision = 0;
11145
11146 if (summary)
11147 summarize_gamma_errors(pm, "alpha mode", 1, 0/*indexed*/);
11148
11149 if (fail(pm))
11150 return;
11151 }
11152 #endif
11153 }
11154 #endif /* PNG_READ_GAMMA_SUPPORTED */
11155 #endif /* PNG_READ_SUPPORTED */
11156
11157 /* INTERLACE MACRO VALIDATION */
11158 /* This is copied verbatim from the specification, it is simply the pass
11159 * number in which each pixel in each 8x8 tile appears. The array must
11160 * be indexed adam7[y][x] and notice that the pass numbers are based at
11161 * 1, not 0 - the base libpng uses.
11162 */
11163 static const
11164 png_byte adam7[8][8] =
11165 {
11166 { 1,6,4,6,2,6,4,6 },
11167 { 7,7,7,7,7,7,7,7 },
11168 { 5,6,5,6,5,6,5,6 },
11169 { 7,7,7,7,7,7,7,7 },
11170 { 3,6,4,6,3,6,4,6 },
11171 { 7,7,7,7,7,7,7,7 },
11172 { 5,6,5,6,5,6,5,6 },
11173 { 7,7,7,7,7,7,7,7 }
11174 };
11175
11176 /* This routine validates all the interlace support macros in png.h for
11177 * a variety of valid PNG widths and heights. It uses a number of similarly
11178 * named internal routines that feed off the above array.
11179 */
11180 static png_uint_32
png_pass_start_row(int pass)11181 png_pass_start_row(int pass)
11182 {
11183 int x, y;
11184 ++pass;
11185 for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
11186 return y;
11187 return 0xf;
11188 }
11189
11190 static png_uint_32
png_pass_start_col(int pass)11191 png_pass_start_col(int pass)
11192 {
11193 int x, y;
11194 ++pass;
11195 for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
11196 return x;
11197 return 0xf;
11198 }
11199
11200 static int
png_pass_row_shift(int pass)11201 png_pass_row_shift(int pass)
11202 {
11203 int x, y, base=(-1), inc=8;
11204 ++pass;
11205 for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
11206 {
11207 if (base == (-1))
11208 base = y;
11209 else if (base == y)
11210 {}
11211 else if (inc == y-base)
11212 base=y;
11213 else if (inc == 8)
11214 inc = y-base, base=y;
11215 else if (inc != y-base)
11216 return 0xff; /* error - more than one 'inc' value! */
11217 }
11218
11219 if (base == (-1)) return 0xfe; /* error - no row in pass! */
11220
11221 /* The shift is always 1, 2 or 3 - no pass has all the rows! */
11222 switch (inc)
11223 {
11224 case 2: return 1;
11225 case 4: return 2;
11226 case 8: return 3;
11227 default: break;
11228 }
11229
11230 /* error - unrecognized 'inc' */
11231 return (inc << 8) + 0xfd;
11232 }
11233
11234 static int
png_pass_col_shift(int pass)11235 png_pass_col_shift(int pass)
11236 {
11237 int x, y, base=(-1), inc=8;
11238 ++pass;
11239 for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
11240 {
11241 if (base == (-1))
11242 base = x;
11243 else if (base == x)
11244 {}
11245 else if (inc == x-base)
11246 base=x;
11247 else if (inc == 8)
11248 inc = x-base, base=x;
11249 else if (inc != x-base)
11250 return 0xff; /* error - more than one 'inc' value! */
11251 }
11252
11253 if (base == (-1)) return 0xfe; /* error - no row in pass! */
11254
11255 /* The shift is always 1, 2 or 3 - no pass has all the rows! */
11256 switch (inc)
11257 {
11258 case 1: return 0; /* pass 7 has all the columns */
11259 case 2: return 1;
11260 case 4: return 2;
11261 case 8: return 3;
11262 default: break;
11263 }
11264
11265 /* error - unrecognized 'inc' */
11266 return (inc << 8) + 0xfd;
11267 }
11268
11269 static png_uint_32
png_row_from_pass_row(png_uint_32 yIn,int pass)11270 png_row_from_pass_row(png_uint_32 yIn, int pass)
11271 {
11272 /* By examination of the array: */
11273 switch (pass)
11274 {
11275 case 0: return yIn * 8;
11276 case 1: return yIn * 8;
11277 case 2: return yIn * 8 + 4;
11278 case 3: return yIn * 4;
11279 case 4: return yIn * 4 + 2;
11280 case 5: return yIn * 2;
11281 case 6: return yIn * 2 + 1;
11282 default: break;
11283 }
11284
11285 return 0xff; /* bad pass number */
11286 }
11287
11288 static png_uint_32
png_col_from_pass_col(png_uint_32 xIn,int pass)11289 png_col_from_pass_col(png_uint_32 xIn, int pass)
11290 {
11291 /* By examination of the array: */
11292 switch (pass)
11293 {
11294 case 0: return xIn * 8;
11295 case 1: return xIn * 8 + 4;
11296 case 2: return xIn * 4;
11297 case 3: return xIn * 4 + 2;
11298 case 4: return xIn * 2;
11299 case 5: return xIn * 2 + 1;
11300 case 6: return xIn;
11301 default: break;
11302 }
11303
11304 return 0xff; /* bad pass number */
11305 }
11306
11307 static int
png_row_in_interlace_pass(png_uint_32 y,int pass)11308 png_row_in_interlace_pass(png_uint_32 y, int pass)
11309 {
11310 /* Is row 'y' in pass 'pass'? */
11311 int x;
11312 y &= 7;
11313 ++pass;
11314 for (x=0; x<8; ++x) if (adam7[y][x] == pass)
11315 return 1;
11316
11317 return 0;
11318 }
11319
11320 static int
png_col_in_interlace_pass(png_uint_32 x,int pass)11321 png_col_in_interlace_pass(png_uint_32 x, int pass)
11322 {
11323 /* Is column 'x' in pass 'pass'? */
11324 int y;
11325 x &= 7;
11326 ++pass;
11327 for (y=0; y<8; ++y) if (adam7[y][x] == pass)
11328 return 1;
11329
11330 return 0;
11331 }
11332
11333 static png_uint_32
png_pass_rows(png_uint_32 height,int pass)11334 png_pass_rows(png_uint_32 height, int pass)
11335 {
11336 png_uint_32 tiles = height>>3;
11337 png_uint_32 rows = 0;
11338 unsigned int x, y;
11339
11340 height &= 7;
11341 ++pass;
11342 for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
11343 {
11344 rows += tiles;
11345 if (y < height) ++rows;
11346 break; /* i.e. break the 'x', column, loop. */
11347 }
11348
11349 return rows;
11350 }
11351
11352 static png_uint_32
png_pass_cols(png_uint_32 width,int pass)11353 png_pass_cols(png_uint_32 width, int pass)
11354 {
11355 png_uint_32 tiles = width>>3;
11356 png_uint_32 cols = 0;
11357 unsigned int x, y;
11358
11359 width &= 7;
11360 ++pass;
11361 for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
11362 {
11363 cols += tiles;
11364 if (x < width) ++cols;
11365 break; /* i.e. break the 'y', row, loop. */
11366 }
11367
11368 return cols;
11369 }
11370
11371 static void
perform_interlace_macro_validation(void)11372 perform_interlace_macro_validation(void)
11373 {
11374 /* The macros to validate, first those that depend only on pass:
11375 *
11376 * PNG_PASS_START_ROW(pass)
11377 * PNG_PASS_START_COL(pass)
11378 * PNG_PASS_ROW_SHIFT(pass)
11379 * PNG_PASS_COL_SHIFT(pass)
11380 */
11381 int pass;
11382
11383 for (pass=0; pass<7; ++pass)
11384 {
11385 png_uint_32 m, f, v;
11386
11387 m = PNG_PASS_START_ROW(pass);
11388 f = png_pass_start_row(pass);
11389 if (m != f)
11390 {
11391 fprintf(stderr, "PNG_PASS_START_ROW(%d) = %u != %x\n", pass, m, f);
11392 exit(99);
11393 }
11394
11395 m = PNG_PASS_START_COL(pass);
11396 f = png_pass_start_col(pass);
11397 if (m != f)
11398 {
11399 fprintf(stderr, "PNG_PASS_START_COL(%d) = %u != %x\n", pass, m, f);
11400 exit(99);
11401 }
11402
11403 m = PNG_PASS_ROW_SHIFT(pass);
11404 f = png_pass_row_shift(pass);
11405 if (m != f)
11406 {
11407 fprintf(stderr, "PNG_PASS_ROW_SHIFT(%d) = %u != %x\n", pass, m, f);
11408 exit(99);
11409 }
11410
11411 m = PNG_PASS_COL_SHIFT(pass);
11412 f = png_pass_col_shift(pass);
11413 if (m != f)
11414 {
11415 fprintf(stderr, "PNG_PASS_COL_SHIFT(%d) = %u != %x\n", pass, m, f);
11416 exit(99);
11417 }
11418
11419 /* Macros that depend on the image or sub-image height too:
11420 *
11421 * PNG_PASS_ROWS(height, pass)
11422 * PNG_PASS_COLS(width, pass)
11423 * PNG_ROW_FROM_PASS_ROW(yIn, pass)
11424 * PNG_COL_FROM_PASS_COL(xIn, pass)
11425 * PNG_ROW_IN_INTERLACE_PASS(y, pass)
11426 * PNG_COL_IN_INTERLACE_PASS(x, pass)
11427 */
11428 for (v=0;;)
11429 {
11430 /* First the base 0 stuff: */
11431 m = PNG_ROW_FROM_PASS_ROW(v, pass);
11432 f = png_row_from_pass_row(v, pass);
11433 if (m != f)
11434 {
11435 fprintf(stderr, "PNG_ROW_FROM_PASS_ROW(%u, %d) = %u != %x\n",
11436 v, pass, m, f);
11437 exit(99);
11438 }
11439
11440 m = PNG_COL_FROM_PASS_COL(v, pass);
11441 f = png_col_from_pass_col(v, pass);
11442 if (m != f)
11443 {
11444 fprintf(stderr, "PNG_COL_FROM_PASS_COL(%u, %d) = %u != %x\n",
11445 v, pass, m, f);
11446 exit(99);
11447 }
11448
11449 m = PNG_ROW_IN_INTERLACE_PASS(v, pass);
11450 f = png_row_in_interlace_pass(v, pass);
11451 if (m != f)
11452 {
11453 fprintf(stderr, "PNG_ROW_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
11454 v, pass, m, f);
11455 exit(99);
11456 }
11457
11458 m = PNG_COL_IN_INTERLACE_PASS(v, pass);
11459 f = png_col_in_interlace_pass(v, pass);
11460 if (m != f)
11461 {
11462 fprintf(stderr, "PNG_COL_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
11463 v, pass, m, f);
11464 exit(99);
11465 }
11466
11467 /* Then the base 1 stuff: */
11468 ++v;
11469 m = PNG_PASS_ROWS(v, pass);
11470 f = png_pass_rows(v, pass);
11471 if (m != f)
11472 {
11473 fprintf(stderr, "PNG_PASS_ROWS(%u, %d) = %u != %x\n",
11474 v, pass, m, f);
11475 exit(99);
11476 }
11477
11478 m = PNG_PASS_COLS(v, pass);
11479 f = png_pass_cols(v, pass);
11480 if (m != f)
11481 {
11482 fprintf(stderr, "PNG_PASS_COLS(%u, %d) = %u != %x\n",
11483 v, pass, m, f);
11484 exit(99);
11485 }
11486
11487 /* Move to the next v - the stepping algorithm starts skipping
11488 * values above 1024.
11489 */
11490 if (v > 1024)
11491 {
11492 if (v == PNG_UINT_31_MAX)
11493 break;
11494
11495 v = (v << 1) ^ v;
11496 if (v >= PNG_UINT_31_MAX)
11497 v = PNG_UINT_31_MAX-1;
11498 }
11499 }
11500 }
11501 }
11502
11503 /* Test color encodings. These values are back-calculated from the published
11504 * chromaticities. The values are accurate to about 14 decimal places; 15 are
11505 * given. These values are much more accurate than the ones given in the spec,
11506 * which typically don't exceed 4 decimal places. This allows testing of the
11507 * libpng code to its theoretical accuracy of 4 decimal places. (If pngvalid
11508 * used the published errors the 'slack' permitted would have to be +/-.5E-4 or
11509 * more.)
11510 *
11511 * The png_modifier code assumes that encodings[0] is sRGB and treats it
11512 * specially: do not change the first entry in this list!
11513 */
11514 static const color_encoding test_encodings[] =
11515 {
11516 /* sRGB: must be first in this list! */
11517 /*gamma:*/ { 1/2.2,
11518 /*red: */ { 0.412390799265959, 0.212639005871510, 0.019330818715592 },
11519 /*green:*/ { 0.357584339383878, 0.715168678767756, 0.119194779794626 },
11520 /*blue: */ { 0.180480788401834, 0.072192315360734, 0.950532152249660} },
11521 /* Kodak ProPhoto (wide gamut) */
11522 /*gamma:*/ { 1/1.6 /*approximate: uses 1.8 power law compared to sRGB 2.4*/,
11523 /*red: */ { 0.797760489672303, 0.288071128229293, 0.000000000000000 },
11524 /*green:*/ { 0.135185837175740, 0.711843217810102, 0.000000000000000 },
11525 /*blue: */ { 0.031349349581525, 0.000085653960605, 0.825104602510460} },
11526 /* Adobe RGB (1998) */
11527 /*gamma:*/ { 1/(2+51./256),
11528 /*red: */ { 0.576669042910131, 0.297344975250536, 0.027031361386412 },
11529 /*green:*/ { 0.185558237906546, 0.627363566255466, 0.070688852535827 },
11530 /*blue: */ { 0.188228646234995, 0.075291458493998, 0.991337536837639} },
11531 /* Adobe Wide Gamut RGB */
11532 /*gamma:*/ { 1/(2+51./256),
11533 /*red: */ { 0.716500716779386, 0.258728243040113, 0.000000000000000 },
11534 /*green:*/ { 0.101020574397477, 0.724682314948566, 0.051211818965388 },
11535 /*blue: */ { 0.146774385252705, 0.016589442011321, 0.773892783545073} },
11536 /* Fake encoding which selects just the green channel */
11537 /*gamma:*/ { 1.45/2.2, /* the 'Mac' gamma */
11538 /*red: */ { 0.716500716779386, 0.000000000000000, 0.000000000000000 },
11539 /*green:*/ { 0.101020574397477, 1.000000000000000, 0.051211818965388 },
11540 /*blue: */ { 0.146774385252705, 0.000000000000000, 0.773892783545073} },
11541 };
11542
11543 /* signal handler
11544 *
11545 * This attempts to trap signals and escape without crashing. It needs a
11546 * context pointer so that it can throw an exception (call longjmp) to recover
11547 * from the condition; this is handled by making the png_modifier used by 'main'
11548 * into a global variable.
11549 */
11550 static png_modifier pm;
11551
signal_handler(int signum)11552 static void signal_handler(int signum)
11553 {
11554
11555 size_t pos = 0;
11556 char msg[64];
11557
11558 pos = safecat(msg, sizeof msg, pos, "caught signal: ");
11559
11560 switch (signum)
11561 {
11562 case SIGABRT:
11563 pos = safecat(msg, sizeof msg, pos, "abort");
11564 break;
11565
11566 case SIGFPE:
11567 pos = safecat(msg, sizeof msg, pos, "floating point exception");
11568 break;
11569
11570 case SIGILL:
11571 pos = safecat(msg, sizeof msg, pos, "illegal instruction");
11572 break;
11573
11574 case SIGINT:
11575 pos = safecat(msg, sizeof msg, pos, "interrupt");
11576 break;
11577
11578 case SIGSEGV:
11579 pos = safecat(msg, sizeof msg, pos, "invalid memory access");
11580 break;
11581
11582 case SIGTERM:
11583 pos = safecat(msg, sizeof msg, pos, "termination request");
11584 break;
11585
11586 default:
11587 pos = safecat(msg, sizeof msg, pos, "unknown ");
11588 pos = safecatn(msg, sizeof msg, pos, signum);
11589 break;
11590 }
11591
11592 store_log(&pm.this, NULL/*png_structp*/, msg, 1/*error*/);
11593
11594 /* And finally throw an exception so we can keep going, unless this is
11595 * SIGTERM in which case stop now.
11596 */
11597 if (signum != SIGTERM)
11598 {
11599 struct exception_context *the_exception_context =
11600 &pm.this.exception_context;
11601
11602 Throw &pm.this;
11603 }
11604
11605 else
11606 exit(1);
11607 }
11608
11609 /* main program */
main(int argc,char ** argv)11610 int main(int argc, char **argv)
11611 {
11612 int summary = 1; /* Print the error summary at the end */
11613 int memstats = 0; /* Print memory statistics at the end */
11614
11615 /* Create the given output file on success: */
11616 const char *touch = NULL;
11617
11618 /* This is an array of standard gamma values (believe it or not I've seen
11619 * every one of these mentioned somewhere.)
11620 *
11621 * In the following list the most useful values are first!
11622 */
11623 static double
11624 gammas[]={2.2, 1.0, 2.2/1.45, 1.8, 1.5, 2.4, 2.5, 2.62, 2.9};
11625
11626 /* This records the command and arguments: */
11627 size_t cp = 0;
11628 char command[1024];
11629
11630 anon_context(&pm.this);
11631
11632 gnu_volatile(summary)
11633 gnu_volatile(memstats)
11634 gnu_volatile(touch)
11635
11636 /* Add appropriate signal handlers, just the ANSI specified ones: */
11637 signal(SIGABRT, signal_handler);
11638 signal(SIGFPE, signal_handler);
11639 signal(SIGILL, signal_handler);
11640 signal(SIGINT, signal_handler);
11641 signal(SIGSEGV, signal_handler);
11642 signal(SIGTERM, signal_handler);
11643
11644 #ifdef HAVE_FEENABLEEXCEPT
11645 /* Only required to enable FP exceptions on platforms where they start off
11646 * disabled; this is not necessary but if it is not done pngvalid will likely
11647 * end up ignoring FP conditions that other platforms fault.
11648 */
11649 feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW);
11650 #endif
11651
11652 modifier_init(&pm);
11653
11654 /* Preallocate the image buffer, because we know how big it needs to be,
11655 * note that, for testing purposes, it is deliberately mis-aligned by tag
11656 * bytes either side. All rows have an additional five bytes of padding for
11657 * overwrite checking.
11658 */
11659 store_ensure_image(&pm.this, NULL, 2, TRANSFORM_ROWMAX, TRANSFORM_HEIGHTMAX);
11660
11661 /* Don't give argv[0], it's normally some horrible libtool string: */
11662 cp = safecat(command, sizeof command, cp, "pngvalid");
11663
11664 /* Default to error on warning: */
11665 pm.this.treat_warnings_as_errors = 1;
11666
11667 /* Default assume_16_bit_calculations appropriately; this tells the checking
11668 * code that 16-bit arithmetic is used for 8-bit samples when it would make a
11669 * difference.
11670 */
11671 pm.assume_16_bit_calculations = PNG_LIBPNG_VER >= 10700;
11672
11673 /* Currently 16 bit expansion happens at the end of the pipeline, so the
11674 * calculations are done in the input bit depth not the output.
11675 *
11676 * TODO: fix this
11677 */
11678 pm.calculations_use_input_precision = 1U;
11679
11680 /* Store the test gammas */
11681 pm.gammas = gammas;
11682 pm.ngammas = ARRAY_SIZE(gammas);
11683 pm.ngamma_tests = 0; /* default to off */
11684
11685 /* Low bit depth gray images don't do well in the gamma tests, until
11686 * this is fixed turn them off for some gamma cases:
11687 */
11688 # ifdef PNG_WRITE_tRNS_SUPPORTED
11689 pm.test_tRNS = 1;
11690 # endif
11691 pm.test_lbg = PNG_LIBPNG_VER >= 10600;
11692 pm.test_lbg_gamma_threshold = 1;
11693 pm.test_lbg_gamma_transform = PNG_LIBPNG_VER >= 10600;
11694 pm.test_lbg_gamma_sbit = 1;
11695 pm.test_lbg_gamma_composition = PNG_LIBPNG_VER >= 10700;
11696
11697 /* And the test encodings */
11698 pm.encodings = test_encodings;
11699 pm.nencodings = ARRAY_SIZE(test_encodings);
11700
11701 # if PNG_LIBPNG_VER < 10700
11702 pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */
11703 # else
11704 pm.sbitlow = 1U;
11705 # endif
11706
11707 /* The following allows results to pass if they correspond to anything in the
11708 * transformed range [input-.5,input+.5]; this is is required because of the
11709 * way libpng treates the 16_TO_8 flag when building the gamma tables in
11710 * releases up to 1.6.0.
11711 *
11712 * TODO: review this
11713 */
11714 pm.use_input_precision_16to8 = 1U;
11715 pm.use_input_precision_sbit = 1U; /* because libpng now rounds sBIT */
11716
11717 /* Some default values (set the behavior for 'make check' here).
11718 * These values simply control the maximum error permitted in the gamma
11719 * transformations. The practial limits for human perception are described
11720 * below (the setting for maxpc16), however for 8 bit encodings it isn't
11721 * possible to meet the accepted capabilities of human vision - i.e. 8 bit
11722 * images can never be good enough, regardless of encoding.
11723 */
11724 pm.maxout8 = .1; /* Arithmetic error in *encoded* value */
11725 pm.maxabs8 = .00005; /* 1/20000 */
11726 pm.maxcalc8 = 1./255; /* +/-1 in 8 bits for compose errors */
11727 pm.maxpc8 = .499; /* I.e., .499% fractional error */
11728 pm.maxout16 = .499; /* Error in *encoded* value */
11729 pm.maxabs16 = .00005;/* 1/20000 */
11730 pm.maxcalc16 =1./65535;/* +/-1 in 16 bits for compose errors */
11731 # if PNG_LIBPNG_VER < 10700
11732 pm.maxcalcG = 1./((1<<PNG_MAX_GAMMA_8)-1);
11733 # else
11734 pm.maxcalcG = 1./((1<<16)-1);
11735 # endif
11736
11737 /* NOTE: this is a reasonable perceptual limit. We assume that humans can
11738 * perceive light level differences of 1% over a 100:1 range, so we need to
11739 * maintain 1 in 10000 accuracy (in linear light space), which is what the
11740 * following guarantees. It also allows significantly higher errors at
11741 * higher 16 bit values, which is important for performance. The actual
11742 * maximum 16 bit error is about +/-1.9 in the fixed point implementation but
11743 * this is only allowed for values >38149 by the following:
11744 */
11745 pm.maxpc16 = .005; /* I.e., 1/200% - 1/20000 */
11746
11747 /* Now parse the command line options. */
11748 while (--argc >= 1)
11749 {
11750 int catmore = 0; /* Set if the argument has an argument. */
11751
11752 /* Record each argument for posterity: */
11753 cp = safecat(command, sizeof command, cp, " ");
11754 cp = safecat(command, sizeof command, cp, *++argv);
11755
11756 if (strcmp(*argv, "-v") == 0)
11757 pm.this.verbose = 1;
11758
11759 else if (strcmp(*argv, "-l") == 0)
11760 pm.log = 1;
11761
11762 else if (strcmp(*argv, "-q") == 0)
11763 summary = pm.this.verbose = pm.log = 0;
11764
11765 else if (strcmp(*argv, "-w") == 0 ||
11766 strcmp(*argv, "--strict") == 0)
11767 pm.this.treat_warnings_as_errors = 1; /* NOTE: this is the default! */
11768
11769 else if (strcmp(*argv, "--nostrict") == 0)
11770 pm.this.treat_warnings_as_errors = 0;
11771
11772 else if (strcmp(*argv, "--speed") == 0)
11773 pm.this.speed = 1, pm.ngamma_tests = pm.ngammas, pm.test_standard = 0,
11774 summary = 0;
11775
11776 else if (strcmp(*argv, "--memory") == 0)
11777 memstats = 1;
11778
11779 else if (strcmp(*argv, "--size") == 0)
11780 pm.test_size = 1;
11781
11782 else if (strcmp(*argv, "--nosize") == 0)
11783 pm.test_size = 0;
11784
11785 else if (strcmp(*argv, "--standard") == 0)
11786 pm.test_standard = 1;
11787
11788 else if (strcmp(*argv, "--nostandard") == 0)
11789 pm.test_standard = 0;
11790
11791 else if (strcmp(*argv, "--transform") == 0)
11792 pm.test_transform = 1;
11793
11794 else if (strcmp(*argv, "--notransform") == 0)
11795 pm.test_transform = 0;
11796
11797 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
11798 else if (strncmp(*argv, "--transform-disable=",
11799 sizeof "--transform-disable") == 0)
11800 {
11801 pm.test_transform = 1;
11802 transform_disable(*argv + sizeof "--transform-disable");
11803 }
11804
11805 else if (strncmp(*argv, "--transform-enable=",
11806 sizeof "--transform-enable") == 0)
11807 {
11808 pm.test_transform = 1;
11809 transform_enable(*argv + sizeof "--transform-enable");
11810 }
11811 #endif /* PNG_READ_TRANSFORMS_SUPPORTED */
11812
11813 else if (strcmp(*argv, "--gamma") == 0)
11814 {
11815 /* Just do two gamma tests here (2.2 and linear) for speed: */
11816 pm.ngamma_tests = 2U;
11817 pm.test_gamma_threshold = 1;
11818 pm.test_gamma_transform = 1;
11819 pm.test_gamma_sbit = 1;
11820 pm.test_gamma_scale16 = 1;
11821 pm.test_gamma_background = 1; /* composition */
11822 pm.test_gamma_alpha_mode = 1;
11823 }
11824
11825 else if (strcmp(*argv, "--nogamma") == 0)
11826 pm.ngamma_tests = 0;
11827
11828 else if (strcmp(*argv, "--gamma-threshold") == 0)
11829 pm.ngamma_tests = 2U, pm.test_gamma_threshold = 1;
11830
11831 else if (strcmp(*argv, "--nogamma-threshold") == 0)
11832 pm.test_gamma_threshold = 0;
11833
11834 else if (strcmp(*argv, "--gamma-transform") == 0)
11835 pm.ngamma_tests = 2U, pm.test_gamma_transform = 1;
11836
11837 else if (strcmp(*argv, "--nogamma-transform") == 0)
11838 pm.test_gamma_transform = 0;
11839
11840 else if (strcmp(*argv, "--gamma-sbit") == 0)
11841 pm.ngamma_tests = 2U, pm.test_gamma_sbit = 1;
11842
11843 else if (strcmp(*argv, "--nogamma-sbit") == 0)
11844 pm.test_gamma_sbit = 0;
11845
11846 else if (strcmp(*argv, "--gamma-16-to-8") == 0)
11847 pm.ngamma_tests = 2U, pm.test_gamma_scale16 = 1;
11848
11849 else if (strcmp(*argv, "--nogamma-16-to-8") == 0)
11850 pm.test_gamma_scale16 = 0;
11851
11852 else if (strcmp(*argv, "--gamma-background") == 0)
11853 pm.ngamma_tests = 2U, pm.test_gamma_background = 1;
11854
11855 else if (strcmp(*argv, "--nogamma-background") == 0)
11856 pm.test_gamma_background = 0;
11857
11858 else if (strcmp(*argv, "--gamma-alpha-mode") == 0)
11859 pm.ngamma_tests = 2U, pm.test_gamma_alpha_mode = 1;
11860
11861 else if (strcmp(*argv, "--nogamma-alpha-mode") == 0)
11862 pm.test_gamma_alpha_mode = 0;
11863
11864 else if (strcmp(*argv, "--expand16") == 0)
11865 pm.test_gamma_expand16 = 1;
11866
11867 else if (strcmp(*argv, "--noexpand16") == 0)
11868 pm.test_gamma_expand16 = 0;
11869
11870 else if (strcmp(*argv, "--low-depth-gray") == 0)
11871 pm.test_lbg = pm.test_lbg_gamma_threshold =
11872 pm.test_lbg_gamma_transform = pm.test_lbg_gamma_sbit =
11873 pm.test_lbg_gamma_composition = 1;
11874
11875 else if (strcmp(*argv, "--nolow-depth-gray") == 0)
11876 pm.test_lbg = pm.test_lbg_gamma_threshold =
11877 pm.test_lbg_gamma_transform = pm.test_lbg_gamma_sbit =
11878 pm.test_lbg_gamma_composition = 0;
11879
11880 # ifdef PNG_WRITE_tRNS_SUPPORTED
11881 else if (strcmp(*argv, "--tRNS") == 0)
11882 pm.test_tRNS = 1;
11883 # endif
11884
11885 else if (strcmp(*argv, "--notRNS") == 0)
11886 pm.test_tRNS = 0;
11887
11888 else if (strcmp(*argv, "--more-gammas") == 0)
11889 pm.ngamma_tests = 3U;
11890
11891 else if (strcmp(*argv, "--all-gammas") == 0)
11892 pm.ngamma_tests = pm.ngammas;
11893
11894 else if (strcmp(*argv, "--progressive-read") == 0)
11895 pm.this.progressive = 1;
11896
11897 else if (strcmp(*argv, "--use-update-info") == 0)
11898 ++pm.use_update_info; /* Can call multiple times */
11899
11900 else if (strcmp(*argv, "--interlace") == 0)
11901 {
11902 # if CAN_WRITE_INTERLACE
11903 pm.interlace_type = PNG_INTERLACE_ADAM7;
11904 # else /* !CAN_WRITE_INTERLACE */
11905 fprintf(stderr, "pngvalid: no write interlace support\n");
11906 return SKIP;
11907 # endif /* !CAN_WRITE_INTERLACE */
11908 }
11909
11910 else if (strcmp(*argv, "--use-input-precision") == 0)
11911 pm.use_input_precision = 1U;
11912
11913 else if (strcmp(*argv, "--use-calculation-precision") == 0)
11914 pm.use_input_precision = 0;
11915
11916 else if (strcmp(*argv, "--calculations-use-input-precision") == 0)
11917 pm.calculations_use_input_precision = 1U;
11918
11919 else if (strcmp(*argv, "--assume-16-bit-calculations") == 0)
11920 pm.assume_16_bit_calculations = 1U;
11921
11922 else if (strcmp(*argv, "--calculations-follow-bit-depth") == 0)
11923 pm.calculations_use_input_precision =
11924 pm.assume_16_bit_calculations = 0;
11925
11926 else if (strcmp(*argv, "--exhaustive") == 0)
11927 pm.test_exhaustive = 1;
11928
11929 else if (argc > 1 && strcmp(*argv, "--sbitlow") == 0)
11930 --argc, pm.sbitlow = (png_byte)atoi(*++argv), catmore = 1;
11931
11932 else if (argc > 1 && strcmp(*argv, "--touch") == 0)
11933 --argc, touch = *++argv, catmore = 1;
11934
11935 else if (argc > 1 && strncmp(*argv, "--max", 5) == 0)
11936 {
11937 --argc;
11938
11939 if (strcmp(5+*argv, "abs8") == 0)
11940 pm.maxabs8 = atof(*++argv);
11941
11942 else if (strcmp(5+*argv, "abs16") == 0)
11943 pm.maxabs16 = atof(*++argv);
11944
11945 else if (strcmp(5+*argv, "calc8") == 0)
11946 pm.maxcalc8 = atof(*++argv);
11947
11948 else if (strcmp(5+*argv, "calc16") == 0)
11949 pm.maxcalc16 = atof(*++argv);
11950
11951 else if (strcmp(5+*argv, "out8") == 0)
11952 pm.maxout8 = atof(*++argv);
11953
11954 else if (strcmp(5+*argv, "out16") == 0)
11955 pm.maxout16 = atof(*++argv);
11956
11957 else if (strcmp(5+*argv, "pc8") == 0)
11958 pm.maxpc8 = atof(*++argv);
11959
11960 else if (strcmp(5+*argv, "pc16") == 0)
11961 pm.maxpc16 = atof(*++argv);
11962
11963 else
11964 {
11965 fprintf(stderr, "pngvalid: %s: unknown 'max' option\n", *argv);
11966 exit(99);
11967 }
11968
11969 catmore = 1;
11970 }
11971
11972 else if (strcmp(*argv, "--log8") == 0)
11973 --argc, pm.log8 = atof(*++argv), catmore = 1;
11974
11975 else if (strcmp(*argv, "--log16") == 0)
11976 --argc, pm.log16 = atof(*++argv), catmore = 1;
11977
11978 #ifdef PNG_SET_OPTION_SUPPORTED
11979 else if (strncmp(*argv, "--option=", 9) == 0)
11980 {
11981 /* Syntax of the argument is <option>:{on|off} */
11982 const char *arg = 9+*argv;
11983 unsigned char option=0, setting=0;
11984
11985 #ifdef PNG_ARM_NEON
11986 if (strncmp(arg, "arm-neon:", 9) == 0)
11987 option = PNG_ARM_NEON, arg += 9;
11988
11989 else
11990 #endif
11991 #ifdef PNG_EXTENSIONS
11992 if (strncmp(arg, "extensions:", 11) == 0)
11993 option = PNG_EXTENSIONS, arg += 11;
11994
11995 else
11996 #endif
11997 #ifdef PNG_MAXIMUM_INFLATE_WINDOW
11998 if (strncmp(arg, "max-inflate-window:", 19) == 0)
11999 option = PNG_MAXIMUM_INFLATE_WINDOW, arg += 19;
12000
12001 else
12002 #endif
12003 {
12004 fprintf(stderr, "pngvalid: %s: %s: unknown option\n", *argv, arg);
12005 exit(99);
12006 }
12007
12008 if (strcmp(arg, "off") == 0)
12009 setting = PNG_OPTION_OFF;
12010
12011 else if (strcmp(arg, "on") == 0)
12012 setting = PNG_OPTION_ON;
12013
12014 else
12015 {
12016 fprintf(stderr,
12017 "pngvalid: %s: %s: unknown setting (use 'on' or 'off')\n",
12018 *argv, arg);
12019 exit(99);
12020 }
12021
12022 pm.this.options[pm.this.noptions].option = option;
12023 pm.this.options[pm.this.noptions++].setting = setting;
12024 }
12025 #endif /* PNG_SET_OPTION_SUPPORTED */
12026
12027 else
12028 {
12029 fprintf(stderr, "pngvalid: %s: unknown argument\n", *argv);
12030 exit(99);
12031 }
12032
12033 if (catmore) /* consumed an extra *argv */
12034 {
12035 cp = safecat(command, sizeof command, cp, " ");
12036 cp = safecat(command, sizeof command, cp, *argv);
12037 }
12038 }
12039
12040 /* If pngvalid is run with no arguments default to a reasonable set of the
12041 * tests.
12042 */
12043 if (pm.test_standard == 0 && pm.test_size == 0 && pm.test_transform == 0 &&
12044 pm.ngamma_tests == 0)
12045 {
12046 /* Make this do all the tests done in the test shell scripts with the same
12047 * parameters, where possible. The limitation is that all the progressive
12048 * read and interlace stuff has to be done in separate runs, so only the
12049 * basic 'standard' and 'size' tests are done.
12050 */
12051 pm.test_standard = 1;
12052 pm.test_size = 1;
12053 pm.test_transform = 1;
12054 pm.ngamma_tests = 2U;
12055 }
12056
12057 if (pm.ngamma_tests > 0 &&
12058 pm.test_gamma_threshold == 0 && pm.test_gamma_transform == 0 &&
12059 pm.test_gamma_sbit == 0 && pm.test_gamma_scale16 == 0 &&
12060 pm.test_gamma_background == 0 && pm.test_gamma_alpha_mode == 0)
12061 {
12062 pm.test_gamma_threshold = 1;
12063 pm.test_gamma_transform = 1;
12064 pm.test_gamma_sbit = 1;
12065 pm.test_gamma_scale16 = 1;
12066 pm.test_gamma_background = 1;
12067 pm.test_gamma_alpha_mode = 1;
12068 }
12069
12070 else if (pm.ngamma_tests == 0)
12071 {
12072 /* Nothing to test so turn everything off: */
12073 pm.test_gamma_threshold = 0;
12074 pm.test_gamma_transform = 0;
12075 pm.test_gamma_sbit = 0;
12076 pm.test_gamma_scale16 = 0;
12077 pm.test_gamma_background = 0;
12078 pm.test_gamma_alpha_mode = 0;
12079 }
12080
12081 Try
12082 {
12083 /* Make useful base images */
12084 make_transform_images(&pm);
12085
12086 /* Perform the standard and gamma tests. */
12087 if (pm.test_standard)
12088 {
12089 perform_interlace_macro_validation();
12090 perform_formatting_test(&pm.this);
12091 # ifdef PNG_READ_SUPPORTED
12092 perform_standard_test(&pm);
12093 # endif
12094 perform_error_test(&pm);
12095 }
12096
12097 /* Various oddly sized images: */
12098 if (pm.test_size)
12099 {
12100 make_size_images(&pm.this);
12101 # ifdef PNG_READ_SUPPORTED
12102 perform_size_test(&pm);
12103 # endif
12104 }
12105
12106 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
12107 /* Combinatorial transforms: */
12108 if (pm.test_transform)
12109 perform_transform_test(&pm);
12110 #endif /* PNG_READ_TRANSFORMS_SUPPORTED */
12111
12112 #ifdef PNG_READ_GAMMA_SUPPORTED
12113 if (pm.ngamma_tests > 0)
12114 perform_gamma_test(&pm, summary);
12115 #endif
12116 }
12117
12118 Catch_anonymous
12119 {
12120 fprintf(stderr, "pngvalid: test aborted (probably failed in cleanup)\n");
12121 if (!pm.this.verbose)
12122 {
12123 if (pm.this.error[0] != 0)
12124 fprintf(stderr, "pngvalid: first error: %s\n", pm.this.error);
12125
12126 fprintf(stderr, "pngvalid: run with -v to see what happened\n");
12127 }
12128 exit(1);
12129 }
12130
12131 if (summary)
12132 {
12133 printf("%s: %s (%s point arithmetic)\n",
12134 (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
12135 pm.this.nwarnings)) ? "FAIL" : "PASS",
12136 command,
12137 #if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || PNG_LIBPNG_VER < 10500
12138 "floating"
12139 #else
12140 "fixed"
12141 #endif
12142 );
12143 }
12144
12145 if (memstats)
12146 {
12147 printf("Allocated memory statistics (in bytes):\n"
12148 "\tread %lu maximum single, %lu peak, %lu total\n"
12149 "\twrite %lu maximum single, %lu peak, %lu total\n",
12150 (unsigned long)pm.this.read_memory_pool.max_max,
12151 (unsigned long)pm.this.read_memory_pool.max_limit,
12152 (unsigned long)pm.this.read_memory_pool.max_total,
12153 (unsigned long)pm.this.write_memory_pool.max_max,
12154 (unsigned long)pm.this.write_memory_pool.max_limit,
12155 (unsigned long)pm.this.write_memory_pool.max_total);
12156 }
12157
12158 /* Do this here to provoke memory corruption errors in memory not directly
12159 * allocated by libpng - not a complete test, but better than nothing.
12160 */
12161 store_delete(&pm.this);
12162
12163 /* Error exit if there are any errors, and maybe if there are any
12164 * warnings.
12165 */
12166 if (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
12167 pm.this.nwarnings))
12168 {
12169 if (!pm.this.verbose)
12170 fprintf(stderr, "pngvalid: %s\n", pm.this.error);
12171
12172 fprintf(stderr, "pngvalid: %d errors, %d warnings\n", pm.this.nerrors,
12173 pm.this.nwarnings);
12174
12175 exit(1);
12176 }
12177
12178 /* Success case. */
12179 if (touch != NULL)
12180 {
12181 FILE *fsuccess = fopen(touch, "wt");
12182
12183 if (fsuccess != NULL)
12184 {
12185 int error = 0;
12186 fprintf(fsuccess, "PNG validation succeeded\n");
12187 fflush(fsuccess);
12188 error = ferror(fsuccess);
12189
12190 if (fclose(fsuccess) || error)
12191 {
12192 fprintf(stderr, "%s: write failed\n", touch);
12193 exit(1);
12194 }
12195 }
12196
12197 else
12198 {
12199 fprintf(stderr, "%s: open failed\n", touch);
12200 exit(1);
12201 }
12202 }
12203
12204 /* This is required because some very minimal configurations do not use it:
12205 */
12206 UNUSED(fail)
12207 return 0;
12208 }
12209 #else /* write or low level APIs not supported */
main(void)12210 int main(void)
12211 {
12212 fprintf(stderr,
12213 "pngvalid: no low level write support in libpng, all tests skipped\n");
12214 /* So the test is skipped: */
12215 return SKIP;
12216 }
12217 #endif
12218