1 /*
2 * jdmaster.c
3 *
4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1991-1997, Thomas G. Lane.
6 * Modified 2002-2009 by Guido Vollbeding.
7 * libjpeg-turbo Modifications:
8 * Copyright (C) 2009-2011, 2016, D. R. Commander.
9 * Copyright (C) 2013, Linaro Limited.
10 * Copyright (C) 2015, Google, Inc.
11 * For conditions of distribution and use, see the accompanying README.ijg
12 * file.
13 *
14 * This file contains master control logic for the JPEG decompressor.
15 * These routines are concerned with selecting the modules to be executed
16 * and with determining the number of passes and the work to be done in each
17 * pass.
18 */
19
20 #define JPEG_INTERNALS
21 #include "jinclude.h"
22 #include "jpeglib.h"
23 #include "jpegcomp.h"
24 #include "jdmaster.h"
25 #include "jsimd.h"
26
27
28 /*
29 * Determine whether merged upsample/color conversion should be used.
30 * CRUCIAL: this must match the actual capabilities of jdmerge.c!
31 */
32
33 LOCAL(boolean)
use_merged_upsample(j_decompress_ptr cinfo)34 use_merged_upsample (j_decompress_ptr cinfo)
35 {
36 #ifdef UPSAMPLE_MERGING_SUPPORTED
37 /* Merging is the equivalent of plain box-filter upsampling */
38 if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling)
39 return FALSE;
40 /* jdmerge.c only supports YCC=>RGB and YCC=>RGB565 color conversion */
41 if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 ||
42 (cinfo->out_color_space != JCS_RGB &&
43 cinfo->out_color_space != JCS_RGB565 &&
44 cinfo->out_color_space != JCS_EXT_RGB &&
45 cinfo->out_color_space != JCS_EXT_RGBX &&
46 cinfo->out_color_space != JCS_EXT_BGR &&
47 cinfo->out_color_space != JCS_EXT_BGRX &&
48 cinfo->out_color_space != JCS_EXT_XBGR &&
49 cinfo->out_color_space != JCS_EXT_XRGB &&
50 cinfo->out_color_space != JCS_EXT_RGBA &&
51 cinfo->out_color_space != JCS_EXT_BGRA &&
52 cinfo->out_color_space != JCS_EXT_ABGR &&
53 cinfo->out_color_space != JCS_EXT_ARGB))
54 return FALSE;
55 if ((cinfo->out_color_space == JCS_RGB565 &&
56 cinfo->out_color_components != 3) ||
57 (cinfo->out_color_space != JCS_RGB565 &&
58 cinfo->out_color_components != rgb_pixelsize[cinfo->out_color_space]))
59 return FALSE;
60 /* and it only handles 2h1v or 2h2v sampling ratios */
61 if (cinfo->comp_info[0].h_samp_factor != 2 ||
62 cinfo->comp_info[1].h_samp_factor != 1 ||
63 cinfo->comp_info[2].h_samp_factor != 1 ||
64 cinfo->comp_info[0].v_samp_factor > 2 ||
65 cinfo->comp_info[1].v_samp_factor != 1 ||
66 cinfo->comp_info[2].v_samp_factor != 1)
67 return FALSE;
68 /* furthermore, it doesn't work if we've scaled the IDCTs differently */
69 if (cinfo->comp_info[0]._DCT_scaled_size != cinfo->_min_DCT_scaled_size ||
70 cinfo->comp_info[1]._DCT_scaled_size != cinfo->_min_DCT_scaled_size ||
71 cinfo->comp_info[2]._DCT_scaled_size != cinfo->_min_DCT_scaled_size)
72 return FALSE;
73 #ifdef WITH_SIMD
74 /* If YCbCr-to-RGB color conversion is SIMD-accelerated but merged upsampling
75 isn't, then disabling merged upsampling is likely to be faster when
76 decompressing YCbCr JPEG images. */
77 if (!jsimd_can_h2v2_merged_upsample() && !jsimd_can_h2v1_merged_upsample() &&
78 jsimd_can_ycc_rgb() && cinfo->jpeg_color_space == JCS_YCbCr &&
79 (cinfo->out_color_space == JCS_RGB ||
80 (cinfo->out_color_space >= JCS_EXT_RGB &&
81 cinfo->out_color_space <= JCS_EXT_ARGB)))
82 return FALSE;
83 #endif
84 /* ??? also need to test for upsample-time rescaling, when & if supported */
85 return TRUE; /* by golly, it'll work... */
86 #else
87 return FALSE;
88 #endif
89 }
90
91
92 /*
93 * Compute output image dimensions and related values.
94 * NOTE: this is exported for possible use by application.
95 * Hence it mustn't do anything that can't be done twice.
96 */
97
98 #if JPEG_LIB_VERSION >= 80
99 GLOBAL(void)
100 #else
101 LOCAL(void)
102 #endif
jpeg_core_output_dimensions(j_decompress_ptr cinfo)103 jpeg_core_output_dimensions (j_decompress_ptr cinfo)
104 /* Do computations that are needed before master selection phase.
105 * This function is used for transcoding and full decompression.
106 */
107 {
108 #ifdef IDCT_SCALING_SUPPORTED
109 int ci;
110 jpeg_component_info *compptr;
111
112 /* Compute actual output image dimensions and DCT scaling choices. */
113 if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom) {
114 /* Provide 1/block_size scaling */
115 cinfo->output_width = (JDIMENSION)
116 jdiv_round_up((long) cinfo->image_width, (long) DCTSIZE);
117 cinfo->output_height = (JDIMENSION)
118 jdiv_round_up((long) cinfo->image_height, (long) DCTSIZE);
119 cinfo->_min_DCT_h_scaled_size = 1;
120 cinfo->_min_DCT_v_scaled_size = 1;
121 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 2) {
122 /* Provide 2/block_size scaling */
123 cinfo->output_width = (JDIMENSION)
124 jdiv_round_up((long) cinfo->image_width * 2L, (long) DCTSIZE);
125 cinfo->output_height = (JDIMENSION)
126 jdiv_round_up((long) cinfo->image_height * 2L, (long) DCTSIZE);
127 cinfo->_min_DCT_h_scaled_size = 2;
128 cinfo->_min_DCT_v_scaled_size = 2;
129 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 3) {
130 /* Provide 3/block_size scaling */
131 cinfo->output_width = (JDIMENSION)
132 jdiv_round_up((long) cinfo->image_width * 3L, (long) DCTSIZE);
133 cinfo->output_height = (JDIMENSION)
134 jdiv_round_up((long) cinfo->image_height * 3L, (long) DCTSIZE);
135 cinfo->_min_DCT_h_scaled_size = 3;
136 cinfo->_min_DCT_v_scaled_size = 3;
137 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 4) {
138 /* Provide 4/block_size scaling */
139 cinfo->output_width = (JDIMENSION)
140 jdiv_round_up((long) cinfo->image_width * 4L, (long) DCTSIZE);
141 cinfo->output_height = (JDIMENSION)
142 jdiv_round_up((long) cinfo->image_height * 4L, (long) DCTSIZE);
143 cinfo->_min_DCT_h_scaled_size = 4;
144 cinfo->_min_DCT_v_scaled_size = 4;
145 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 5) {
146 /* Provide 5/block_size scaling */
147 cinfo->output_width = (JDIMENSION)
148 jdiv_round_up((long) cinfo->image_width * 5L, (long) DCTSIZE);
149 cinfo->output_height = (JDIMENSION)
150 jdiv_round_up((long) cinfo->image_height * 5L, (long) DCTSIZE);
151 cinfo->_min_DCT_h_scaled_size = 5;
152 cinfo->_min_DCT_v_scaled_size = 5;
153 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 6) {
154 /* Provide 6/block_size scaling */
155 cinfo->output_width = (JDIMENSION)
156 jdiv_round_up((long) cinfo->image_width * 6L, (long) DCTSIZE);
157 cinfo->output_height = (JDIMENSION)
158 jdiv_round_up((long) cinfo->image_height * 6L, (long) DCTSIZE);
159 cinfo->_min_DCT_h_scaled_size = 6;
160 cinfo->_min_DCT_v_scaled_size = 6;
161 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 7) {
162 /* Provide 7/block_size scaling */
163 cinfo->output_width = (JDIMENSION)
164 jdiv_round_up((long) cinfo->image_width * 7L, (long) DCTSIZE);
165 cinfo->output_height = (JDIMENSION)
166 jdiv_round_up((long) cinfo->image_height * 7L, (long) DCTSIZE);
167 cinfo->_min_DCT_h_scaled_size = 7;
168 cinfo->_min_DCT_v_scaled_size = 7;
169 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 8) {
170 /* Provide 8/block_size scaling */
171 cinfo->output_width = (JDIMENSION)
172 jdiv_round_up((long) cinfo->image_width * 8L, (long) DCTSIZE);
173 cinfo->output_height = (JDIMENSION)
174 jdiv_round_up((long) cinfo->image_height * 8L, (long) DCTSIZE);
175 cinfo->_min_DCT_h_scaled_size = 8;
176 cinfo->_min_DCT_v_scaled_size = 8;
177 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 9) {
178 /* Provide 9/block_size scaling */
179 cinfo->output_width = (JDIMENSION)
180 jdiv_round_up((long) cinfo->image_width * 9L, (long) DCTSIZE);
181 cinfo->output_height = (JDIMENSION)
182 jdiv_round_up((long) cinfo->image_height * 9L, (long) DCTSIZE);
183 cinfo->_min_DCT_h_scaled_size = 9;
184 cinfo->_min_DCT_v_scaled_size = 9;
185 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 10) {
186 /* Provide 10/block_size scaling */
187 cinfo->output_width = (JDIMENSION)
188 jdiv_round_up((long) cinfo->image_width * 10L, (long) DCTSIZE);
189 cinfo->output_height = (JDIMENSION)
190 jdiv_round_up((long) cinfo->image_height * 10L, (long) DCTSIZE);
191 cinfo->_min_DCT_h_scaled_size = 10;
192 cinfo->_min_DCT_v_scaled_size = 10;
193 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 11) {
194 /* Provide 11/block_size scaling */
195 cinfo->output_width = (JDIMENSION)
196 jdiv_round_up((long) cinfo->image_width * 11L, (long) DCTSIZE);
197 cinfo->output_height = (JDIMENSION)
198 jdiv_round_up((long) cinfo->image_height * 11L, (long) DCTSIZE);
199 cinfo->_min_DCT_h_scaled_size = 11;
200 cinfo->_min_DCT_v_scaled_size = 11;
201 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 12) {
202 /* Provide 12/block_size scaling */
203 cinfo->output_width = (JDIMENSION)
204 jdiv_round_up((long) cinfo->image_width * 12L, (long) DCTSIZE);
205 cinfo->output_height = (JDIMENSION)
206 jdiv_round_up((long) cinfo->image_height * 12L, (long) DCTSIZE);
207 cinfo->_min_DCT_h_scaled_size = 12;
208 cinfo->_min_DCT_v_scaled_size = 12;
209 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 13) {
210 /* Provide 13/block_size scaling */
211 cinfo->output_width = (JDIMENSION)
212 jdiv_round_up((long) cinfo->image_width * 13L, (long) DCTSIZE);
213 cinfo->output_height = (JDIMENSION)
214 jdiv_round_up((long) cinfo->image_height * 13L, (long) DCTSIZE);
215 cinfo->_min_DCT_h_scaled_size = 13;
216 cinfo->_min_DCT_v_scaled_size = 13;
217 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 14) {
218 /* Provide 14/block_size scaling */
219 cinfo->output_width = (JDIMENSION)
220 jdiv_round_up((long) cinfo->image_width * 14L, (long) DCTSIZE);
221 cinfo->output_height = (JDIMENSION)
222 jdiv_round_up((long) cinfo->image_height * 14L, (long) DCTSIZE);
223 cinfo->_min_DCT_h_scaled_size = 14;
224 cinfo->_min_DCT_v_scaled_size = 14;
225 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 15) {
226 /* Provide 15/block_size scaling */
227 cinfo->output_width = (JDIMENSION)
228 jdiv_round_up((long) cinfo->image_width * 15L, (long) DCTSIZE);
229 cinfo->output_height = (JDIMENSION)
230 jdiv_round_up((long) cinfo->image_height * 15L, (long) DCTSIZE);
231 cinfo->_min_DCT_h_scaled_size = 15;
232 cinfo->_min_DCT_v_scaled_size = 15;
233 } else {
234 /* Provide 16/block_size scaling */
235 cinfo->output_width = (JDIMENSION)
236 jdiv_round_up((long) cinfo->image_width * 16L, (long) DCTSIZE);
237 cinfo->output_height = (JDIMENSION)
238 jdiv_round_up((long) cinfo->image_height * 16L, (long) DCTSIZE);
239 cinfo->_min_DCT_h_scaled_size = 16;
240 cinfo->_min_DCT_v_scaled_size = 16;
241 }
242
243 /* Recompute dimensions of components */
244 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
245 ci++, compptr++) {
246 compptr->_DCT_h_scaled_size = cinfo->_min_DCT_h_scaled_size;
247 compptr->_DCT_v_scaled_size = cinfo->_min_DCT_v_scaled_size;
248 }
249
250 #else /* !IDCT_SCALING_SUPPORTED */
251
252 /* Hardwire it to "no scaling" */
253 cinfo->output_width = cinfo->image_width;
254 cinfo->output_height = cinfo->image_height;
255 /* jdinput.c has already initialized DCT_scaled_size,
256 * and has computed unscaled downsampled_width and downsampled_height.
257 */
258
259 #endif /* IDCT_SCALING_SUPPORTED */
260 }
261
262
263 /*
264 * Compute output image dimensions and related values.
265 * NOTE: this is exported for possible use by application.
266 * Hence it mustn't do anything that can't be done twice.
267 * Also note that it may be called before the master module is initialized!
268 */
269
270 GLOBAL(void)
jpeg_calc_output_dimensions(j_decompress_ptr cinfo)271 jpeg_calc_output_dimensions (j_decompress_ptr cinfo)
272 /* Do computations that are needed before master selection phase */
273 {
274 #ifdef IDCT_SCALING_SUPPORTED
275 int ci;
276 jpeg_component_info *compptr;
277 #endif
278
279 /* Prevent application from calling me at wrong times */
280 if (cinfo->global_state != DSTATE_READY)
281 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
282
283 /* Compute core output image dimensions and DCT scaling choices. */
284 jpeg_core_output_dimensions(cinfo);
285
286 #ifdef IDCT_SCALING_SUPPORTED
287
288 /* In selecting the actual DCT scaling for each component, we try to
289 * scale up the chroma components via IDCT scaling rather than upsampling.
290 * This saves time if the upsampler gets to use 1:1 scaling.
291 * Note this code adapts subsampling ratios which are powers of 2.
292 */
293 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
294 ci++, compptr++) {
295 int ssize = cinfo->_min_DCT_scaled_size;
296 while (ssize < DCTSIZE &&
297 ((cinfo->max_h_samp_factor * cinfo->_min_DCT_scaled_size) %
298 (compptr->h_samp_factor * ssize * 2) == 0) &&
299 ((cinfo->max_v_samp_factor * cinfo->_min_DCT_scaled_size) %
300 (compptr->v_samp_factor * ssize * 2) == 0)) {
301 ssize = ssize * 2;
302 }
303 #if JPEG_LIB_VERSION >= 70
304 compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = ssize;
305 #else
306 compptr->DCT_scaled_size = ssize;
307 #endif
308 }
309
310 /* Recompute downsampled dimensions of components;
311 * application needs to know these if using raw downsampled data.
312 */
313 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
314 ci++, compptr++) {
315 /* Size in samples, after IDCT scaling */
316 compptr->downsampled_width = (JDIMENSION)
317 jdiv_round_up((long) cinfo->image_width *
318 (long) (compptr->h_samp_factor * compptr->_DCT_scaled_size),
319 (long) (cinfo->max_h_samp_factor * DCTSIZE));
320 compptr->downsampled_height = (JDIMENSION)
321 jdiv_round_up((long) cinfo->image_height *
322 (long) (compptr->v_samp_factor * compptr->_DCT_scaled_size),
323 (long) (cinfo->max_v_samp_factor * DCTSIZE));
324 }
325
326 #else /* !IDCT_SCALING_SUPPORTED */
327
328 /* Hardwire it to "no scaling" */
329 cinfo->output_width = cinfo->image_width;
330 cinfo->output_height = cinfo->image_height;
331 /* jdinput.c has already initialized DCT_scaled_size to DCTSIZE,
332 * and has computed unscaled downsampled_width and downsampled_height.
333 */
334
335 #endif /* IDCT_SCALING_SUPPORTED */
336
337 /* Report number of components in selected colorspace. */
338 /* Probably this should be in the color conversion module... */
339 switch (cinfo->out_color_space) {
340 case JCS_GRAYSCALE:
341 cinfo->out_color_components = 1;
342 break;
343 case JCS_RGB:
344 case JCS_EXT_RGB:
345 case JCS_EXT_RGBX:
346 case JCS_EXT_BGR:
347 case JCS_EXT_BGRX:
348 case JCS_EXT_XBGR:
349 case JCS_EXT_XRGB:
350 case JCS_EXT_RGBA:
351 case JCS_EXT_BGRA:
352 case JCS_EXT_ABGR:
353 case JCS_EXT_ARGB:
354 cinfo->out_color_components = rgb_pixelsize[cinfo->out_color_space];
355 break;
356 case JCS_YCbCr:
357 case JCS_RGB565:
358 cinfo->out_color_components = 3;
359 break;
360 case JCS_CMYK:
361 case JCS_YCCK:
362 cinfo->out_color_components = 4;
363 break;
364 default: /* else must be same colorspace as in file */
365 cinfo->out_color_components = cinfo->num_components;
366 break;
367 }
368 cinfo->output_components = (cinfo->quantize_colors ? 1 :
369 cinfo->out_color_components);
370
371 /* See if upsampler will want to emit more than one row at a time */
372 if (use_merged_upsample(cinfo))
373 cinfo->rec_outbuf_height = cinfo->max_v_samp_factor;
374 else
375 cinfo->rec_outbuf_height = 1;
376 }
377
378
379 /*
380 * Several decompression processes need to range-limit values to the range
381 * 0..MAXJSAMPLE; the input value may fall somewhat outside this range
382 * due to noise introduced by quantization, roundoff error, etc. These
383 * processes are inner loops and need to be as fast as possible. On most
384 * machines, particularly CPUs with pipelines or instruction prefetch,
385 * a (subscript-check-less) C table lookup
386 * x = sample_range_limit[x];
387 * is faster than explicit tests
388 * if (x < 0) x = 0;
389 * else if (x > MAXJSAMPLE) x = MAXJSAMPLE;
390 * These processes all use a common table prepared by the routine below.
391 *
392 * For most steps we can mathematically guarantee that the initial value
393 * of x is within MAXJSAMPLE+1 of the legal range, so a table running from
394 * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient. But for the initial
395 * limiting step (just after the IDCT), a wildly out-of-range value is
396 * possible if the input data is corrupt. To avoid any chance of indexing
397 * off the end of memory and getting a bad-pointer trap, we perform the
398 * post-IDCT limiting thus:
399 * x = range_limit[x & MASK];
400 * where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit
401 * samples. Under normal circumstances this is more than enough range and
402 * a correct output will be generated; with bogus input data the mask will
403 * cause wraparound, and we will safely generate a bogus-but-in-range output.
404 * For the post-IDCT step, we want to convert the data from signed to unsigned
405 * representation by adding CENTERJSAMPLE at the same time that we limit it.
406 * So the post-IDCT limiting table ends up looking like this:
407 * CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE,
408 * MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
409 * 0 (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
410 * 0,1,...,CENTERJSAMPLE-1
411 * Negative inputs select values from the upper half of the table after
412 * masking.
413 *
414 * We can save some space by overlapping the start of the post-IDCT table
415 * with the simpler range limiting table. The post-IDCT table begins at
416 * sample_range_limit + CENTERJSAMPLE.
417 */
418
419 LOCAL(void)
prepare_range_limit_table(j_decompress_ptr cinfo)420 prepare_range_limit_table (j_decompress_ptr cinfo)
421 /* Allocate and fill in the sample_range_limit table */
422 {
423 JSAMPLE *table;
424 int i;
425
426 table = (JSAMPLE *)
427 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
428 (5 * (MAXJSAMPLE+1) + CENTERJSAMPLE) * sizeof(JSAMPLE));
429 table += (MAXJSAMPLE+1); /* allow negative subscripts of simple table */
430 cinfo->sample_range_limit = table;
431 /* First segment of "simple" table: limit[x] = 0 for x < 0 */
432 MEMZERO(table - (MAXJSAMPLE+1), (MAXJSAMPLE+1) * sizeof(JSAMPLE));
433 /* Main part of "simple" table: limit[x] = x */
434 for (i = 0; i <= MAXJSAMPLE; i++)
435 table[i] = (JSAMPLE) i;
436 table += CENTERJSAMPLE; /* Point to where post-IDCT table starts */
437 /* End of simple table, rest of first half of post-IDCT table */
438 for (i = CENTERJSAMPLE; i < 2*(MAXJSAMPLE+1); i++)
439 table[i] = MAXJSAMPLE;
440 /* Second half of post-IDCT table */
441 MEMZERO(table + (2 * (MAXJSAMPLE+1)),
442 (2 * (MAXJSAMPLE+1) - CENTERJSAMPLE) * sizeof(JSAMPLE));
443 MEMCOPY(table + (4 * (MAXJSAMPLE+1) - CENTERJSAMPLE),
444 cinfo->sample_range_limit, CENTERJSAMPLE * sizeof(JSAMPLE));
445 }
446
447
448 /*
449 * Master selection of decompression modules.
450 * This is done once at jpeg_start_decompress time. We determine
451 * which modules will be used and give them appropriate initialization calls.
452 * We also initialize the decompressor input side to begin consuming data.
453 *
454 * Since jpeg_read_header has finished, we know what is in the SOF
455 * and (first) SOS markers. We also have all the application parameter
456 * settings.
457 */
458
459 LOCAL(void)
master_selection(j_decompress_ptr cinfo)460 master_selection (j_decompress_ptr cinfo)
461 {
462 my_master_ptr master = (my_master_ptr) cinfo->master;
463 boolean use_c_buffer;
464 long samplesperrow;
465 JDIMENSION jd_samplesperrow;
466
467 /* Initialize dimensions and other stuff */
468 jpeg_calc_output_dimensions(cinfo);
469 prepare_range_limit_table(cinfo);
470
471 /* Width of an output scanline must be representable as JDIMENSION. */
472 samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components;
473 jd_samplesperrow = (JDIMENSION) samplesperrow;
474 if ((long) jd_samplesperrow != samplesperrow)
475 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
476
477 /* Initialize my private state */
478 master->pass_number = 0;
479 master->using_merged_upsample = use_merged_upsample(cinfo);
480
481 /* Color quantizer selection */
482 master->quantizer_1pass = NULL;
483 master->quantizer_2pass = NULL;
484 /* No mode changes if not using buffered-image mode. */
485 if (! cinfo->quantize_colors || ! cinfo->buffered_image) {
486 cinfo->enable_1pass_quant = FALSE;
487 cinfo->enable_external_quant = FALSE;
488 cinfo->enable_2pass_quant = FALSE;
489 }
490 if (cinfo->quantize_colors) {
491 if (cinfo->raw_data_out)
492 ERREXIT(cinfo, JERR_NOTIMPL);
493 /* 2-pass quantizer only works in 3-component color space. */
494 if (cinfo->out_color_components != 3) {
495 cinfo->enable_1pass_quant = TRUE;
496 cinfo->enable_external_quant = FALSE;
497 cinfo->enable_2pass_quant = FALSE;
498 cinfo->colormap = NULL;
499 } else if (cinfo->colormap != NULL) {
500 cinfo->enable_external_quant = TRUE;
501 } else if (cinfo->two_pass_quantize) {
502 cinfo->enable_2pass_quant = TRUE;
503 } else {
504 cinfo->enable_1pass_quant = TRUE;
505 }
506
507 if (cinfo->enable_1pass_quant) {
508 #ifdef QUANT_1PASS_SUPPORTED
509 jinit_1pass_quantizer(cinfo);
510 master->quantizer_1pass = cinfo->cquantize;
511 #else
512 ERREXIT(cinfo, JERR_NOT_COMPILED);
513 #endif
514 }
515
516 /* We use the 2-pass code to map to external colormaps. */
517 if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) {
518 #ifdef QUANT_2PASS_SUPPORTED
519 jinit_2pass_quantizer(cinfo);
520 master->quantizer_2pass = cinfo->cquantize;
521 #else
522 ERREXIT(cinfo, JERR_NOT_COMPILED);
523 #endif
524 }
525 /* If both quantizers are initialized, the 2-pass one is left active;
526 * this is necessary for starting with quantization to an external map.
527 */
528 }
529
530 /* Post-processing: in particular, color conversion first */
531 if (! cinfo->raw_data_out) {
532 if (master->using_merged_upsample) {
533 #ifdef UPSAMPLE_MERGING_SUPPORTED
534 jinit_merged_upsampler(cinfo); /* does color conversion too */
535 #else
536 ERREXIT(cinfo, JERR_NOT_COMPILED);
537 #endif
538 } else {
539 jinit_color_deconverter(cinfo);
540 jinit_upsampler(cinfo);
541 }
542 jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant);
543 }
544 /* Inverse DCT */
545 jinit_inverse_dct(cinfo);
546 /* Entropy decoding: either Huffman or arithmetic coding. */
547 if (cinfo->arith_code) {
548 #ifdef D_ARITH_CODING_SUPPORTED
549 jinit_arith_decoder(cinfo);
550 #else
551 ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
552 #endif
553 } else {
554 if (cinfo->progressive_mode) {
555 #ifdef D_PROGRESSIVE_SUPPORTED
556 jinit_phuff_decoder(cinfo);
557 #else
558 ERREXIT(cinfo, JERR_NOT_COMPILED);
559 #endif
560 } else
561 jinit_huff_decoder(cinfo);
562 }
563
564 /* Initialize principal buffer controllers. */
565 use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image;
566 jinit_d_coef_controller(cinfo, use_c_buffer);
567
568 if (! cinfo->raw_data_out)
569 jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */);
570
571 /* We can now tell the memory manager to allocate virtual arrays. */
572 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
573
574 /* Initialize input side of decompressor to consume first scan. */
575 (*cinfo->inputctl->start_input_pass) (cinfo);
576
577 /* Set the first and last iMCU columns to decompress from single-scan images.
578 * By default, decompress all of the iMCU columns.
579 */
580 cinfo->master->first_iMCU_col = 0;
581 cinfo->master->last_iMCU_col = cinfo->MCUs_per_row - 1;
582
583 #ifdef D_MULTISCAN_FILES_SUPPORTED
584 /* If jpeg_start_decompress will read the whole file, initialize
585 * progress monitoring appropriately. The input step is counted
586 * as one pass.
587 */
588 if (cinfo->progress != NULL && ! cinfo->buffered_image &&
589 cinfo->inputctl->has_multiple_scans) {
590 int nscans;
591 /* Estimate number of scans to set pass_limit. */
592 if (cinfo->progressive_mode) {
593 /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */
594 nscans = 2 + 3 * cinfo->num_components;
595 } else {
596 /* For a nonprogressive multiscan file, estimate 1 scan per component. */
597 nscans = cinfo->num_components;
598 }
599 cinfo->progress->pass_counter = 0L;
600 cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans;
601 cinfo->progress->completed_passes = 0;
602 cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2);
603 /* Count the input pass as done */
604 master->pass_number++;
605 }
606 #endif /* D_MULTISCAN_FILES_SUPPORTED */
607 }
608
609
610 /*
611 * Per-pass setup.
612 * This is called at the beginning of each output pass. We determine which
613 * modules will be active during this pass and give them appropriate
614 * start_pass calls. We also set is_dummy_pass to indicate whether this
615 * is a "real" output pass or a dummy pass for color quantization.
616 * (In the latter case, jdapistd.c will crank the pass to completion.)
617 */
618
619 METHODDEF(void)
prepare_for_output_pass(j_decompress_ptr cinfo)620 prepare_for_output_pass (j_decompress_ptr cinfo)
621 {
622 my_master_ptr master = (my_master_ptr) cinfo->master;
623
624 if (master->pub.is_dummy_pass) {
625 #ifdef QUANT_2PASS_SUPPORTED
626 /* Final pass of 2-pass quantization */
627 master->pub.is_dummy_pass = FALSE;
628 (*cinfo->cquantize->start_pass) (cinfo, FALSE);
629 (*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST);
630 (*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST);
631 #else
632 ERREXIT(cinfo, JERR_NOT_COMPILED);
633 #endif /* QUANT_2PASS_SUPPORTED */
634 } else {
635 if (cinfo->quantize_colors && cinfo->colormap == NULL) {
636 /* Select new quantization method */
637 if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) {
638 cinfo->cquantize = master->quantizer_2pass;
639 master->pub.is_dummy_pass = TRUE;
640 } else if (cinfo->enable_1pass_quant) {
641 cinfo->cquantize = master->quantizer_1pass;
642 } else {
643 ERREXIT(cinfo, JERR_MODE_CHANGE);
644 }
645 }
646 (*cinfo->idct->start_pass) (cinfo);
647 (*cinfo->coef->start_output_pass) (cinfo);
648 if (! cinfo->raw_data_out) {
649 if (! master->using_merged_upsample)
650 (*cinfo->cconvert->start_pass) (cinfo);
651 (*cinfo->upsample->start_pass) (cinfo);
652 if (cinfo->quantize_colors)
653 (*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass);
654 (*cinfo->post->start_pass) (cinfo,
655 (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
656 (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
657 }
658 }
659
660 /* Set up progress monitor's pass info if present */
661 if (cinfo->progress != NULL) {
662 cinfo->progress->completed_passes = master->pass_number;
663 cinfo->progress->total_passes = master->pass_number +
664 (master->pub.is_dummy_pass ? 2 : 1);
665 /* In buffered-image mode, we assume one more output pass if EOI not
666 * yet reached, but no more passes if EOI has been reached.
667 */
668 if (cinfo->buffered_image && ! cinfo->inputctl->eoi_reached) {
669 cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1);
670 }
671 }
672 }
673
674
675 /*
676 * Finish up at end of an output pass.
677 */
678
679 METHODDEF(void)
finish_output_pass(j_decompress_ptr cinfo)680 finish_output_pass (j_decompress_ptr cinfo)
681 {
682 my_master_ptr master = (my_master_ptr) cinfo->master;
683
684 if (cinfo->quantize_colors)
685 (*cinfo->cquantize->finish_pass) (cinfo);
686 master->pass_number++;
687 }
688
689
690 #ifdef D_MULTISCAN_FILES_SUPPORTED
691
692 /*
693 * Switch to a new external colormap between output passes.
694 */
695
696 GLOBAL(void)
jpeg_new_colormap(j_decompress_ptr cinfo)697 jpeg_new_colormap (j_decompress_ptr cinfo)
698 {
699 my_master_ptr master = (my_master_ptr) cinfo->master;
700
701 /* Prevent application from calling me at wrong times */
702 if (cinfo->global_state != DSTATE_BUFIMAGE)
703 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
704
705 if (cinfo->quantize_colors && cinfo->enable_external_quant &&
706 cinfo->colormap != NULL) {
707 /* Select 2-pass quantizer for external colormap use */
708 cinfo->cquantize = master->quantizer_2pass;
709 /* Notify quantizer of colormap change */
710 (*cinfo->cquantize->new_color_map) (cinfo);
711 master->pub.is_dummy_pass = FALSE; /* just in case */
712 } else
713 ERREXIT(cinfo, JERR_MODE_CHANGE);
714 }
715
716 #endif /* D_MULTISCAN_FILES_SUPPORTED */
717
718
719 /*
720 * Initialize master decompression control and select active modules.
721 * This is performed at the start of jpeg_start_decompress.
722 */
723
724 GLOBAL(void)
jinit_master_decompress(j_decompress_ptr cinfo)725 jinit_master_decompress (j_decompress_ptr cinfo)
726 {
727 my_master_ptr master = (my_master_ptr) cinfo->master;
728
729 master->pub.prepare_for_output_pass = prepare_for_output_pass;
730 master->pub.finish_output_pass = finish_output_pass;
731
732 master->pub.is_dummy_pass = FALSE;
733 master->pub.jinit_upsampler_no_alloc = FALSE;
734
735 master_selection(cinfo);
736 }
737