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1 
2 /* pngstruct.h - header file for PNG reference library
3  *
4  * Last changed in libpng 1.6.18 [July 23, 2015]
5  * Copyright (c) 1998-2015 Glenn Randers-Pehrson
6  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
8  *
9  * This code is released under the libpng license.
10  * For conditions of distribution and use, see the disclaimer
11  * and license in png.h
12  */
13 
14 /* The structure that holds the information to read and write PNG files.
15  * The only people who need to care about what is inside of this are the
16  * people who will be modifying the library for their own special needs.
17  * It should NOT be accessed directly by an application.
18  */
19 
20 #ifndef PNGSTRUCT_H
21 #define PNGSTRUCT_H
22 /* zlib.h defines the structure z_stream, an instance of which is included
23  * in this structure and is required for decompressing the LZ compressed
24  * data in PNG files.
25  */
26 #ifndef ZLIB_CONST
27    /* We must ensure that zlib uses 'const' in declarations. */
28 #  define ZLIB_CONST
29 #endif
30 #include "zlib.h"
31 #ifdef const
32    /* zlib.h sometimes #defines const to nothing, undo this. */
33 #  undef const
34 #endif
35 
36 /* zlib.h has mediocre z_const use before 1.2.6, this stuff is for compatibility
37  * with older builds.
38  */
39 #if ZLIB_VERNUM < 0x1260
40 #  define PNGZ_MSG_CAST(s) png_constcast(char*,s)
41 #  define PNGZ_INPUT_CAST(b) png_constcast(png_bytep,b)
42 #else
43 #  define PNGZ_MSG_CAST(s) (s)
44 #  define PNGZ_INPUT_CAST(b) (b)
45 #endif
46 
47 /* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib
48  * can handle at once.  This type need be no larger than 16 bits (so maximum of
49  * 65535), this define allows us to discover how big it is, but limited by the
50  * maximuum for png_size_t.  The value can be overriden in a library build
51  * (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably
52  * lower value (e.g. 255 works).  A lower value may help memory usage (slightly)
53  * and may even improve performance on some systems (and degrade it on others.)
54  */
55 #ifndef ZLIB_IO_MAX
56 #  define ZLIB_IO_MAX ((uInt)-1)
57 #endif
58 
59 #ifdef PNG_WRITE_SUPPORTED
60 /* The type of a compression buffer list used by the write code. */
61 typedef struct png_compression_buffer
62 {
63    struct png_compression_buffer *next;
64    png_byte                       output[1]; /* actually zbuf_size */
65 } png_compression_buffer, *png_compression_bufferp;
66 
67 #define PNG_COMPRESSION_BUFFER_SIZE(pp)\
68    (offsetof(png_compression_buffer, output) + (pp)->zbuffer_size)
69 #endif
70 
71 /* Colorspace support; structures used in png_struct, png_info and in internal
72  * functions to hold and communicate information about the color space.
73  *
74  * PNG_COLORSPACE_SUPPORTED is only required if the application will perform
75  * colorspace corrections, otherwise all the colorspace information can be
76  * skipped and the size of libpng can be reduced (significantly) by compiling
77  * out the colorspace support.
78  */
79 #ifdef PNG_COLORSPACE_SUPPORTED
80 /* The chromaticities of the red, green and blue colorants and the chromaticity
81  * of the corresponding white point (i.e. of rgb(1.0,1.0,1.0)).
82  */
83 typedef struct png_xy
84 {
85    png_fixed_point redx, redy;
86    png_fixed_point greenx, greeny;
87    png_fixed_point bluex, bluey;
88    png_fixed_point whitex, whitey;
89 } png_xy;
90 
91 /* The same data as above but encoded as CIE XYZ values.  When this data comes
92  * from chromaticities the sum of the Y values is assumed to be 1.0
93  */
94 typedef struct png_XYZ
95 {
96    png_fixed_point red_X, red_Y, red_Z;
97    png_fixed_point green_X, green_Y, green_Z;
98    png_fixed_point blue_X, blue_Y, blue_Z;
99 } png_XYZ;
100 #endif /* COLORSPACE */
101 
102 #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
103 /* A colorspace is all the above plus, potentially, profile information;
104  * however at present libpng does not use the profile internally so it is only
105  * stored in the png_info struct (if iCCP is supported.)  The rendering intent
106  * is retained here and is checked.
107  *
108  * The file gamma encoding information is also stored here and gamma correction
109  * is done by libpng, whereas color correction must currently be done by the
110  * application.
111  */
112 typedef struct png_colorspace
113 {
114 #ifdef PNG_GAMMA_SUPPORTED
115    png_fixed_point gamma;        /* File gamma */
116 #endif
117 
118 #ifdef PNG_COLORSPACE_SUPPORTED
119    png_xy      end_points_xy;    /* End points as chromaticities */
120    png_XYZ     end_points_XYZ;   /* End points as CIE XYZ colorant values */
121    png_uint_16 rendering_intent; /* Rendering intent of a profile */
122 #endif
123 
124    /* Flags are always defined to simplify the code. */
125    png_uint_16 flags;            /* As defined below */
126 } png_colorspace, * PNG_RESTRICT png_colorspacerp;
127 
128 typedef const png_colorspace * PNG_RESTRICT png_const_colorspacerp;
129 
130 /* General flags for the 'flags' field */
131 #define PNG_COLORSPACE_HAVE_GAMMA           0x0001
132 #define PNG_COLORSPACE_HAVE_ENDPOINTS       0x0002
133 #define PNG_COLORSPACE_HAVE_INTENT          0x0004
134 #define PNG_COLORSPACE_FROM_gAMA            0x0008
135 #define PNG_COLORSPACE_FROM_cHRM            0x0010
136 #define PNG_COLORSPACE_FROM_sRGB            0x0020
137 #define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0040
138 #define PNG_COLORSPACE_MATCHES_sRGB         0x0080 /* exact match on profile */
139 #define PNG_COLORSPACE_INVALID              0x8000
140 #define PNG_COLORSPACE_CANCEL(flags)        (0xffff ^ (flags))
141 #endif /* COLORSPACE || GAMMA */
142 
143 #ifdef PNG_INDEX_SUPPORTED
144 /* png_line_index_struct records an index point, where we impose an index point
145  * to be located at the beginning of a line for simplifying the implementation.
146  */
147 typedef struct png_line_index_struct
148 {
149    // state of the lz decoder
150    z_streamp   z_state;
151 
152    // the IDAT header position of the chunk, which the index point is in
153    png_uint_32  stream_idat_position;
154 
155    // we intend to record the offset of the index point in the chunk,
156    // but we record the number of remaining bytes in the chunk after the
157    // index point. That's because PNG processes a chunk this way.
158    png_uint_32  bytes_left_in_idat;
159 
160    // decompressed data of the previous row
161    png_bytep   prev_row;
162 } png_line_index;
163 typedef png_line_index FAR * png_line_indexp;
164 
165 typedef struct png_index_struct
166 {
167    // A temporary variable used when we build the index. The variable records
168    // the IDAT header position of the last chunk read in so far.
169    png_uint_32  stream_idat_position;
170 
171    // line index information about each passes
172 
173    // the number of index points in each pass
174    png_uint_32  size[7];
175 
176    // the line span of two index points of each pass
177    png_uint_32  step[7];
178 
179    // the index points of each pass
180    png_line_indexp  *pass_line_index[7];
181 } png_index;
182 typedef png_index FAR * png_indexp;
183 
184 #define INDEX_SAMPLE_SIZE 254
185 #endif
186 
187 struct png_struct_def
188 {
189 #ifdef PNG_SETJMP_SUPPORTED
190    jmp_buf jmp_buf_local;     /* New name in 1.6.0 for jmp_buf in png_struct */
191    png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */
192    jmp_buf *jmp_buf_ptr;      /* passed to longjmp_fn */
193    size_t jmp_buf_size;       /* size of the above, if allocated */
194 #endif
195    png_error_ptr error_fn;    /* function for printing errors and aborting */
196 #ifdef PNG_WARNINGS_SUPPORTED
197    png_error_ptr warning_fn;  /* function for printing warnings */
198 #endif
199    png_voidp error_ptr;       /* user supplied struct for error functions */
200    png_rw_ptr write_data_fn;  /* function for writing output data */
201    png_rw_ptr read_data_fn;   /* function for reading input data */
202 #ifdef PNG_INDEX_SUPPORTED
203    png_seek_ptr seek_data_fn; /* function for seeking input data */
204 #endif
205    png_voidp io_ptr;          /* ptr to application struct for I/O functions */
206 
207 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
208    png_user_transform_ptr read_user_transform_fn; /* user read transform */
209 #endif
210 
211 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
212    png_user_transform_ptr write_user_transform_fn; /* user write transform */
213 #endif
214 
215 /* These were added in libpng-1.0.2 */
216 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
217 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
218     defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
219    png_voidp user_transform_ptr; /* user supplied struct for user transform */
220    png_byte user_transform_depth;    /* bit depth of user transformed pixels */
221    png_byte user_transform_channels; /* channels in user transformed pixels */
222 #endif
223 #endif
224 
225    png_uint_32 mode;          /* tells us where we are in the PNG file */
226    png_uint_32 flags;         /* flags indicating various things to libpng */
227    png_uint_32 transformations; /* which transformations to perform */
228 
229    png_uint_32 zowner;        /* ID (chunk type) of zstream owner, 0 if none */
230    z_stream    zstream;       /* decompression structure */
231 
232 #ifdef PNG_WRITE_SUPPORTED
233    png_compression_bufferp zbuffer_list; /* Created on demand during write */
234    uInt                    zbuffer_size; /* size of the actual buffer */
235 
236    int zlib_level;            /* holds zlib compression level */
237    int zlib_method;           /* holds zlib compression method */
238    int zlib_window_bits;      /* holds zlib compression window bits */
239    int zlib_mem_level;        /* holds zlib compression memory level */
240    int zlib_strategy;         /* holds zlib compression strategy */
241 #endif
242 /* Added at libpng 1.5.4 */
243 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
244    int zlib_text_level;            /* holds zlib compression level */
245    int zlib_text_method;           /* holds zlib compression method */
246    int zlib_text_window_bits;      /* holds zlib compression window bits */
247    int zlib_text_mem_level;        /* holds zlib compression memory level */
248    int zlib_text_strategy;         /* holds zlib compression strategy */
249 #endif
250 /* End of material added at libpng 1.5.4 */
251 /* Added at libpng 1.6.0 */
252 #ifdef PNG_WRITE_SUPPORTED
253    int zlib_set_level;        /* Actual values set into the zstream on write */
254    int zlib_set_method;
255    int zlib_set_window_bits;
256    int zlib_set_mem_level;
257    int zlib_set_strategy;
258 #endif
259 
260    png_uint_32 width;         /* width of image in pixels */
261    png_uint_32 height;        /* height of image in pixels */
262    png_uint_32 num_rows;      /* number of rows in current pass */
263    png_uint_32 usr_width;     /* width of row at start of write */
264    png_size_t rowbytes;       /* size of row in bytes */
265    png_uint_32 iwidth;        /* width of current interlaced row in pixels */
266    png_uint_32 row_number;    /* current row in interlace pass */
267    png_uint_32 chunk_name;    /* PNG_CHUNK() id of current chunk */
268    png_bytep prev_row;        /* buffer to save previous (unfiltered) row.
269                                * While reading this is a pointer into
270                                * big_prev_row; while writing it is separately
271                                * allocated if needed.
272                                */
273    png_bytep row_buf;         /* buffer to save current (unfiltered) row.
274                                * While reading, this is a pointer into
275                                * big_row_buf; while writing it is separately
276                                * allocated.
277                                */
278 #ifdef PNG_WRITE_FILTER_SUPPORTED
279    png_bytep try_row;    /* buffer to save trial row when filtering */
280    png_bytep tst_row;    /* buffer to save best trial row when filtering */
281 #endif
282    png_size_t info_rowbytes;  /* Added in 1.5.4: cache of updated row bytes */
283 
284    png_uint_32 idat_size;     /* current IDAT size for read */
285    png_uint_32 crc;           /* current chunk CRC value */
286    png_colorp palette;        /* palette from the input file */
287    png_uint_16 num_palette;   /* number of color entries in palette */
288 
289 /* Added at libpng-1.5.10 */
290 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
291    int num_palette_max;       /* maximum palette index found in IDAT */
292 #endif
293 
294    png_uint_16 num_trans;     /* number of transparency values */
295    png_byte compression;      /* file compression type (always 0) */
296    png_byte filter;           /* file filter type (always 0) */
297    png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
298    png_byte pass;             /* current interlace pass (0 - 6) */
299    png_byte do_filter;        /* row filter flags (see PNG_FILTER_ below ) */
300    png_byte color_type;       /* color type of file */
301    png_byte bit_depth;        /* bit depth of file */
302    png_byte usr_bit_depth;    /* bit depth of users row: write only */
303    png_byte pixel_depth;      /* number of bits per pixel */
304    png_byte channels;         /* number of channels in file */
305 #ifdef PNG_WRITE_SUPPORTED
306    png_byte usr_channels;     /* channels at start of write: write only */
307 #endif
308    png_byte sig_bytes;        /* magic bytes read/written from start of file */
309    png_byte maximum_pixel_depth;
310                               /* pixel depth used for the row buffers */
311    png_byte transformed_pixel_depth;
312                               /* pixel depth after read/write transforms */
313 #if PNG_ZLIB_VERNUM >= 0x1240
314    png_byte zstream_start;    /* at start of an input zlib stream */
315 #endif /* Zlib >= 1.2.4 */
316 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
317    png_uint_16 filler;           /* filler bytes for pixel expansion */
318 #endif
319 
320 #if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
321    defined(PNG_READ_ALPHA_MODE_SUPPORTED)
322    png_byte background_gamma_type;
323    png_fixed_point background_gamma;
324    png_color_16 background;   /* background color in screen gamma space */
325 #ifdef PNG_READ_GAMMA_SUPPORTED
326    png_color_16 background_1; /* background normalized to gamma 1.0 */
327 #endif
328 #endif /* bKGD */
329 
330 #ifdef PNG_WRITE_FLUSH_SUPPORTED
331    png_flush_ptr output_flush_fn; /* Function for flushing output */
332    png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */
333    png_uint_32 flush_rows;    /* number of rows written since last flush */
334 #endif
335 
336 #ifdef PNG_READ_GAMMA_SUPPORTED
337    int gamma_shift;      /* number of "insignificant" bits in 16-bit gamma */
338    png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
339 
340    png_bytep gamma_table;     /* gamma table for 8-bit depth files */
341    png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
342 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
343    defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
344    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
345    png_bytep gamma_from_1;    /* converts from 1.0 to screen */
346    png_bytep gamma_to_1;      /* converts from file to 1.0 */
347    png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
348    png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
349 #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
350 #endif
351 
352 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
353    png_color_8 sig_bit;       /* significant bits in each available channel */
354 #endif
355 
356 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
357    png_color_8 shift;         /* shift for significant bit tranformation */
358 #endif
359 
360 #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
361  || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
362    png_bytep trans_alpha;           /* alpha values for paletted files */
363    png_color_16 trans_color;  /* transparent color for non-paletted files */
364 #endif
365 
366    png_read_status_ptr read_row_fn;   /* called after each row is decoded */
367    png_write_status_ptr write_row_fn; /* called after each row is encoded */
368 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
369    png_progressive_info_ptr info_fn; /* called after header data fully read */
370    png_progressive_row_ptr row_fn;   /* called after a prog. row is decoded */
371    png_progressive_end_ptr end_fn;   /* called after image is complete */
372    png_bytep save_buffer_ptr;        /* current location in save_buffer */
373    png_bytep save_buffer;            /* buffer for previously read data */
374    png_bytep current_buffer_ptr;     /* current location in current_buffer */
375    png_bytep current_buffer;         /* buffer for recently used data */
376    png_uint_32 push_length;          /* size of current input chunk */
377    png_uint_32 skip_length;          /* bytes to skip in input data */
378    png_size_t save_buffer_size;      /* amount of data now in save_buffer */
379    png_size_t save_buffer_max;       /* total size of save_buffer */
380    png_size_t buffer_size;           /* total amount of available input data */
381    png_size_t current_buffer_size;   /* amount of data now in current_buffer */
382    int process_mode;                 /* what push library is currently doing */
383    int cur_palette;                  /* current push library palette index */
384 
385 #endif /* PROGRESSIVE_READ */
386 
387 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
388 /* For the Borland special 64K segment handler */
389    png_bytepp offset_table_ptr;
390    png_bytep offset_table;
391    png_uint_16 offset_table_number;
392    png_uint_16 offset_table_count;
393    png_uint_16 offset_table_count_free;
394 #endif
395 
396 #ifdef PNG_READ_QUANTIZE_SUPPORTED
397    png_bytep palette_lookup; /* lookup table for quantizing */
398    png_bytep quantize_index; /* index translation for palette files */
399 #endif
400 
401 /* Options */
402 #ifdef PNG_SET_OPTION_SUPPORTED
403    png_byte options;           /* On/off state (up to 4 options) */
404 #endif
405 
406 #if PNG_LIBPNG_VER < 10700
407 /* To do: remove this from libpng-1.7 */
408 #ifdef PNG_TIME_RFC1123_SUPPORTED
409    char time_buffer[29]; /* String to hold RFC 1123 time text */
410 #endif
411 #endif
412 
413 /* New members added in libpng-1.0.6 */
414 
415    png_uint_32 free_me;    /* flags items libpng is responsible for freeing */
416 
417 #ifdef PNG_USER_CHUNKS_SUPPORTED
418    png_voidp user_chunk_ptr;
419 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
420    png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
421 #endif
422 #endif
423 
424 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
425    int          unknown_default; /* As PNG_HANDLE_* */
426    unsigned int num_chunk_list;  /* Number of entries in the list */
427    png_bytep    chunk_list;      /* List of png_byte[5]; the textual chunk name
428                                   * followed by a PNG_HANDLE_* byte */
429 #endif
430 
431 /* New members added in libpng-1.0.3 */
432 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
433    png_byte rgb_to_gray_status;
434    /* Added in libpng 1.5.5 to record setting of coefficients: */
435    png_byte rgb_to_gray_coefficients_set;
436    /* These were changed from png_byte in libpng-1.0.6 */
437    png_uint_16 rgb_to_gray_red_coeff;
438    png_uint_16 rgb_to_gray_green_coeff;
439    /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */
440 #endif
441 
442 /* New member added in libpng-1.0.4 (renamed in 1.0.9) */
443 #if defined(PNG_MNG_FEATURES_SUPPORTED)
444 /* Changed from png_byte to png_uint_32 at version 1.2.0 */
445    png_uint_32 mng_features_permitted;
446 #endif
447 
448 /* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
449 #ifdef PNG_MNG_FEATURES_SUPPORTED
450    png_byte filter_type;
451 #endif
452 
453 /* New members added in libpng-1.2.0 */
454 
455 /* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
456 #ifdef PNG_USER_MEM_SUPPORTED
457    png_voidp mem_ptr;             /* user supplied struct for mem functions */
458    png_malloc_ptr malloc_fn;      /* function for allocating memory */
459    png_free_ptr free_fn;          /* function for freeing memory */
460 #endif
461 
462 /* New member added in libpng-1.0.13 and 1.2.0 */
463    png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */
464 
465 #ifdef PNG_READ_QUANTIZE_SUPPORTED
466 /* The following three members were added at version 1.0.14 and 1.2.4 */
467    png_bytep quantize_sort;          /* working sort array */
468    png_bytep index_to_palette;       /* where the original index currently is
469                                         in the palette */
470    png_bytep palette_to_index;       /* which original index points to this
471                                          palette color */
472 #endif
473 
474 /* New members added in libpng-1.0.16 and 1.2.6 */
475    png_byte compression_type;
476 
477 #ifdef PNG_USER_LIMITS_SUPPORTED
478    png_uint_32 user_width_max;
479    png_uint_32 user_height_max;
480 
481    /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
482     * chunks that can be stored (0 means unlimited).
483     */
484    png_uint_32 user_chunk_cache_max;
485 
486    /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
487     * can occupy when decompressed.  0 means unlimited.
488     */
489    png_alloc_size_t user_chunk_malloc_max;
490 #endif
491 
492 /* New member added in libpng-1.0.25 and 1.2.17 */
493 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
494    /* Temporary storage for unknown chunk that the library doesn't recognize,
495     * used while reading the chunk.
496     */
497    png_unknown_chunk unknown_chunk;
498 #endif
499 
500 /* New member added in libpng-1.2.26 */
501   png_size_t old_big_row_buf_size;
502 
503 #ifdef PNG_READ_SUPPORTED
504 /* New member added in libpng-1.2.30 */
505   png_bytep        read_buffer;      /* buffer for reading chunk data */
506   png_alloc_size_t read_buffer_size; /* current size of the buffer */
507 #endif
508 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
509   uInt             IDAT_read_size;   /* limit on read buffer size for IDAT */
510 #endif
511 
512 #ifdef PNG_IO_STATE_SUPPORTED
513 /* New member added in libpng-1.4.0 */
514    png_uint_32 io_state;
515 #endif
516 
517 /* New member added in libpng-1.5.6 */
518    png_bytep big_prev_row;
519 
520 /* New member added in libpng-1.5.7 */
521    void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
522       png_bytep row, png_const_bytep prev_row);
523 
524 #ifdef PNG_READ_SUPPORTED
525 #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
526    png_colorspace   colorspace;
527 #endif
528 #endif
529 
530 #ifdef PNG_INDEX_SUPPORTED
531    png_indexp index;
532    png_uint_32 total_data_read;
533 #endif
534 
535 };
536 #endif /* PNGSTRUCT_H */
537