2 /* pngstruct.h - header file for PNG reference library
4 * Copyright (c) 2018-2019 Cosmin Truta
5 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
6 * Copyright (c) 1996-1997 Andreas Dilger
7 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
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
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.
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
27 /* We must ensure that zlib uses 'const' in declarations. */
32 /* zlib.h sometimes #defines const to nothing, undo this. */
36 /* zlib.h has mediocre z_const use before 1.2.6, this stuff is for compatibility
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)
43 # define PNGZ_MSG_CAST(s) (s)
44 # define PNGZ_INPUT_CAST(b) (b)
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 * maximum for size_t. The value can be overridden 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.)
56 # define ZLIB_IO_MAX ((uInt)-1)
59 #ifdef PNG_WRITE_SUPPORTED
60 /* The type of a compression buffer list used by the write code. */
61 typedef struct png_compression_buffer
63 struct png_compression_buffer
*next
;
64 png_byte output
[1]; /* actually zbuf_size */
65 } png_compression_buffer
, *png_compression_bufferp
;
67 #define PNG_COMPRESSION_BUFFER_SIZE(pp)\
68 (offsetof(png_compression_buffer, output) + (pp)->zbuffer_size)
71 /* Colorspace support; structures used in png_struct, png_info and in internal
72 * functions to hold and communicate information about the color space.
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.
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)).
85 png_fixed_point redx
, redy
;
86 png_fixed_point greenx
, greeny
;
87 png_fixed_point bluex
, bluey
;
88 png_fixed_point whitex
, whitey
;
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
94 typedef struct png_XYZ
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
;
100 #endif /* COLORSPACE */
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.
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
112 typedef struct png_colorspace
114 #ifdef PNG_GAMMA_SUPPORTED
115 png_fixed_point gamma
; /* File gamma */
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 */
124 /* Flags are always defined to simplify the code. */
125 png_uint_16 flags
; /* As defined below */
126 } png_colorspace
, * PNG_RESTRICT png_colorspacerp
;
128 typedef const png_colorspace
* PNG_RESTRICT png_const_colorspacerp
;
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 */
143 struct png_struct_def
145 #ifdef PNG_SETJMP_SUPPORTED
146 jmp_buf jmp_buf_local
; /* New name in 1.6.0 for jmp_buf in png_struct */
147 png_longjmp_ptr longjmp_fn
;/* setjmp non-local goto function. */
148 jmp_buf *jmp_buf_ptr
; /* passed to longjmp_fn */
149 size_t jmp_buf_size
; /* size of the above, if allocated */
151 png_error_ptr error_fn
; /* function for printing errors and aborting */
152 #ifdef PNG_WARNINGS_SUPPORTED
153 png_error_ptr warning_fn
; /* function for printing warnings */
155 png_voidp error_ptr
; /* user supplied struct for error functions */
156 png_rw_ptr write_data_fn
; /* function for writing output data */
157 png_rw_ptr read_data_fn
; /* function for reading input data */
158 png_voidp io_ptr
; /* ptr to application struct for I/O functions */
160 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
161 png_user_transform_ptr read_user_transform_fn
; /* user read transform */
164 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
165 png_user_transform_ptr write_user_transform_fn
; /* user write transform */
168 /* These were added in libpng-1.0.2 */
169 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
170 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
171 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
172 png_voidp user_transform_ptr
; /* user supplied struct for user transform */
173 png_byte user_transform_depth
; /* bit depth of user transformed pixels */
174 png_byte user_transform_channels
; /* channels in user transformed pixels */
178 png_uint_32 mode
; /* tells us where we are in the PNG file */
179 png_uint_32 flags
; /* flags indicating various things to libpng */
180 png_uint_32 transformations
; /* which transformations to perform */
182 png_uint_32 zowner
; /* ID (chunk type) of zstream owner, 0 if none */
183 z_stream zstream
; /* decompression structure */
185 #ifdef PNG_WRITE_SUPPORTED
186 png_compression_bufferp zbuffer_list
; /* Created on demand during write */
187 uInt zbuffer_size
; /* size of the actual buffer */
189 int zlib_level
; /* holds zlib compression level */
190 int zlib_method
; /* holds zlib compression method */
191 int zlib_window_bits
; /* holds zlib compression window bits */
192 int zlib_mem_level
; /* holds zlib compression memory level */
193 int zlib_strategy
; /* holds zlib compression strategy */
195 /* Added at libpng 1.5.4 */
196 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
197 int zlib_text_level
; /* holds zlib compression level */
198 int zlib_text_method
; /* holds zlib compression method */
199 int zlib_text_window_bits
; /* holds zlib compression window bits */
200 int zlib_text_mem_level
; /* holds zlib compression memory level */
201 int zlib_text_strategy
; /* holds zlib compression strategy */
203 /* End of material added at libpng 1.5.4 */
204 /* Added at libpng 1.6.0 */
205 #ifdef PNG_WRITE_SUPPORTED
206 int zlib_set_level
; /* Actual values set into the zstream on write */
208 int zlib_set_window_bits
;
209 int zlib_set_mem_level
;
210 int zlib_set_strategy
;
213 png_uint_32 width
; /* width of image in pixels */
214 png_uint_32 height
; /* height of image in pixels */
215 png_uint_32 num_rows
; /* number of rows in current pass */
216 png_uint_32 usr_width
; /* width of row at start of write */
217 size_t rowbytes
; /* size of row in bytes */
218 png_uint_32 iwidth
; /* width of current interlaced row in pixels */
219 png_uint_32 row_number
; /* current row in interlace pass */
220 png_uint_32 chunk_name
; /* PNG_CHUNK() id of current chunk */
221 png_bytep prev_row
; /* buffer to save previous (unfiltered) row.
222 * While reading this is a pointer into
223 * big_prev_row; while writing it is separately
224 * allocated if needed.
226 png_bytep row_buf
; /* buffer to save current (unfiltered) row.
227 * While reading, this is a pointer into
228 * big_row_buf; while writing it is separately
231 #ifdef PNG_WRITE_FILTER_SUPPORTED
232 png_bytep try_row
; /* buffer to save trial row when filtering */
233 png_bytep tst_row
; /* buffer to save best trial row when filtering */
235 size_t info_rowbytes
; /* Added in 1.5.4: cache of updated row bytes */
237 png_uint_32 idat_size
; /* current IDAT size for read */
238 png_uint_32 crc
; /* current chunk CRC value */
239 png_colorp palette
; /* palette from the input file */
240 png_uint_16 num_palette
; /* number of color entries in palette */
242 /* Added at libpng-1.5.10 */
243 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
244 int num_palette_max
; /* maximum palette index found in IDAT */
247 png_uint_16 num_trans
; /* number of transparency values */
248 png_byte compression
; /* file compression type (always 0) */
249 png_byte filter
; /* file filter type (always 0) */
250 png_byte interlaced
; /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
251 png_byte pass
; /* current interlace pass (0 - 6) */
252 png_byte do_filter
; /* row filter flags (see PNG_FILTER_ in png.h ) */
253 png_byte color_type
; /* color type of file */
254 png_byte bit_depth
; /* bit depth of file */
255 png_byte usr_bit_depth
; /* bit depth of users row: write only */
256 png_byte pixel_depth
; /* number of bits per pixel */
257 png_byte channels
; /* number of channels in file */
258 #ifdef PNG_WRITE_SUPPORTED
259 png_byte usr_channels
; /* channels at start of write: write only */
261 png_byte sig_bytes
; /* magic bytes read/written from start of file */
262 png_byte maximum_pixel_depth
;
263 /* pixel depth used for the row buffers */
264 png_byte transformed_pixel_depth
;
265 /* pixel depth after read/write transforms */
266 #if ZLIB_VERNUM >= 0x1240
267 png_byte zstream_start
; /* at start of an input zlib stream */
268 #endif /* Zlib >= 1.2.4 */
269 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
270 png_uint_16 filler
; /* filler bytes for pixel expansion */
273 #if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
274 defined(PNG_READ_ALPHA_MODE_SUPPORTED)
275 png_byte background_gamma_type
;
276 png_fixed_point background_gamma
;
277 png_color_16 background
; /* background color in screen gamma space */
278 #ifdef PNG_READ_GAMMA_SUPPORTED
279 png_color_16 background_1
; /* background normalized to gamma 1.0 */
283 #ifdef PNG_WRITE_FLUSH_SUPPORTED
284 png_flush_ptr output_flush_fn
; /* Function for flushing output */
285 png_uint_32 flush_dist
; /* how many rows apart to flush, 0 - no flush */
286 png_uint_32 flush_rows
; /* number of rows written since last flush */
289 #ifdef PNG_READ_GAMMA_SUPPORTED
290 int gamma_shift
; /* number of "insignificant" bits in 16-bit gamma */
291 png_fixed_point screen_gamma
; /* screen gamma value (display_exponent) */
293 png_bytep gamma_table
; /* gamma table for 8-bit depth files */
294 png_uint_16pp gamma_16_table
; /* gamma table for 16-bit depth files */
295 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
296 defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
297 defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
298 png_bytep gamma_from_1
; /* converts from 1.0 to screen */
299 png_bytep gamma_to_1
; /* converts from file to 1.0 */
300 png_uint_16pp gamma_16_from_1
; /* converts from 1.0 to screen */
301 png_uint_16pp gamma_16_to_1
; /* converts from file to 1.0 */
302 #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
305 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
306 png_color_8 sig_bit
; /* significant bits in each available channel */
309 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
310 png_color_8 shift
; /* shift for significant bit transformation */
313 #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
314 || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
315 png_bytep trans_alpha
; /* alpha values for paletted files */
316 png_color_16 trans_color
; /* transparent color for non-paletted files */
319 png_read_status_ptr read_row_fn
; /* called after each row is decoded */
320 png_write_status_ptr write_row_fn
; /* called after each row is encoded */
321 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
322 png_progressive_info_ptr info_fn
; /* called after header data fully read */
323 png_progressive_row_ptr row_fn
; /* called after a prog. row is decoded */
324 png_progressive_end_ptr end_fn
; /* called after image is complete */
325 png_bytep save_buffer_ptr
; /* current location in save_buffer */
326 png_bytep save_buffer
; /* buffer for previously read data */
327 png_bytep current_buffer_ptr
; /* current location in current_buffer */
328 png_bytep current_buffer
; /* buffer for recently used data */
329 png_uint_32 push_length
; /* size of current input chunk */
330 png_uint_32 skip_length
; /* bytes to skip in input data */
331 size_t save_buffer_size
; /* amount of data now in save_buffer */
332 size_t save_buffer_max
; /* total size of save_buffer */
333 size_t buffer_size
; /* total amount of available input data */
334 size_t current_buffer_size
; /* amount of data now in current_buffer */
335 int process_mode
; /* what push library is currently doing */
336 int cur_palette
; /* current push library palette index */
338 #endif /* PROGRESSIVE_READ */
340 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
341 /* For the Borland special 64K segment handler */
342 png_bytepp offset_table_ptr
;
343 png_bytep offset_table
;
344 png_uint_16 offset_table_number
;
345 png_uint_16 offset_table_count
;
346 png_uint_16 offset_table_count_free
;
349 #ifdef PNG_READ_QUANTIZE_SUPPORTED
350 png_bytep palette_lookup
; /* lookup table for quantizing */
351 png_bytep quantize_index
; /* index translation for palette files */
355 #ifdef PNG_SET_OPTION_SUPPORTED
356 png_uint_32 options
; /* On/off state (up to 16 options) */
359 #if PNG_LIBPNG_VER < 10700
360 /* To do: remove this from libpng-1.7 */
361 #ifdef PNG_TIME_RFC1123_SUPPORTED
362 char time_buffer
[29]; /* String to hold RFC 1123 time text */
366 /* New members added in libpng-1.0.6 */
368 png_uint_32 free_me
; /* flags items libpng is responsible for freeing */
370 #ifdef PNG_USER_CHUNKS_SUPPORTED
371 png_voidp user_chunk_ptr
;
372 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
373 png_user_chunk_ptr read_user_chunk_fn
; /* user read chunk handler */
377 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
378 int unknown_default
; /* As PNG_HANDLE_* */
379 unsigned int num_chunk_list
; /* Number of entries in the list */
380 png_bytep chunk_list
; /* List of png_byte[5]; the textual chunk name
381 * followed by a PNG_HANDLE_* byte */
384 /* New members added in libpng-1.0.3 */
385 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
386 png_byte rgb_to_gray_status
;
387 /* Added in libpng 1.5.5 to record setting of coefficients: */
388 png_byte rgb_to_gray_coefficients_set
;
389 /* These were changed from png_byte in libpng-1.0.6 */
390 png_uint_16 rgb_to_gray_red_coeff
;
391 png_uint_16 rgb_to_gray_green_coeff
;
392 /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */
395 /* New member added in libpng-1.6.36 */
396 #if defined(PNG_READ_EXPAND_SUPPORTED) && \
397 defined(PNG_ARM_NEON_IMPLEMENTATION)
398 png_bytep riffled_palette
; /* buffer for accelerated palette expansion */
401 /* New member added in libpng-1.0.4 (renamed in 1.0.9) */
402 #if defined(PNG_MNG_FEATURES_SUPPORTED)
403 /* Changed from png_byte to png_uint_32 at version 1.2.0 */
404 png_uint_32 mng_features_permitted
;
407 /* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
408 #ifdef PNG_MNG_FEATURES_SUPPORTED
409 png_byte filter_type
;
412 /* New members added in libpng-1.2.0 */
414 /* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
415 #ifdef PNG_USER_MEM_SUPPORTED
416 png_voidp mem_ptr
; /* user supplied struct for mem functions */
417 png_malloc_ptr malloc_fn
; /* function for allocating memory */
418 png_free_ptr free_fn
; /* function for freeing memory */
421 /* New member added in libpng-1.0.13 and 1.2.0 */
422 png_bytep big_row_buf
; /* buffer to save current (unfiltered) row */
424 #ifdef PNG_READ_QUANTIZE_SUPPORTED
425 /* The following three members were added at version 1.0.14 and 1.2.4 */
426 png_bytep quantize_sort
; /* working sort array */
427 png_bytep index_to_palette
; /* where the original index currently is
429 png_bytep palette_to_index
; /* which original index points to this
433 /* New members added in libpng-1.0.16 and 1.2.6 */
434 png_byte compression_type
;
436 #ifdef PNG_USER_LIMITS_SUPPORTED
437 png_uint_32 user_width_max
;
438 png_uint_32 user_height_max
;
440 /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
441 * chunks that can be stored (0 means unlimited).
443 png_uint_32 user_chunk_cache_max
;
445 /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
446 * can occupy when decompressed. 0 means unlimited.
448 png_alloc_size_t user_chunk_malloc_max
;
451 /* New member added in libpng-1.0.25 and 1.2.17 */
452 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
453 /* Temporary storage for unknown chunk that the library doesn't recognize,
454 * used while reading the chunk.
456 png_unknown_chunk unknown_chunk
;
459 /* New member added in libpng-1.2.26 */
460 size_t old_big_row_buf_size
;
462 #ifdef PNG_READ_SUPPORTED
463 /* New member added in libpng-1.2.30 */
464 png_bytep read_buffer
; /* buffer for reading chunk data */
465 png_alloc_size_t read_buffer_size
; /* current size of the buffer */
467 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
468 uInt IDAT_read_size
; /* limit on read buffer size for IDAT */
471 #ifdef PNG_IO_STATE_SUPPORTED
472 /* New member added in libpng-1.4.0 */
473 png_uint_32 io_state
;
476 /* New member added in libpng-1.5.6 */
477 png_bytep big_prev_row
;
479 /* New member added in libpng-1.5.7 */
480 void (*read_filter
[PNG_FILTER_VALUE_LAST
-1])(png_row_infop row_info
,
481 png_bytep row
, png_const_bytep prev_row
);
483 #ifdef PNG_READ_SUPPORTED
484 #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
485 png_colorspace colorspace
;
489 #endif /* PNGSTRUCT_H */