WDL/libpng/pngstruct.h

   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/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 struct png_struct_def
 144 {
 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 */
 150 #endif
 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 */
 154 #endif
 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 */
 159
 160 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
 161    png_user_transform_ptr read_user_transform_fn; /* user read transform */
 162 #endif
 163
 164 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
 165    png_user_transform_ptr write_user_transform_fn; /* user write transform */
 166 #endif
 167
 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 */
 175 #endif
 176 #endif
 177
 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 */
 181
 182    png_uint_32 zowner;        /* ID (chunk type) of zstream owner, 0 if none */
 183    z_stream    zstream;       /* decompression structure */
 184
 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 */
 188
 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 */
 194 #endif
 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 */
 202 #endif
 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 */
 207    int zlib_set_method;
 208    int zlib_set_window_bits;
 209    int zlib_set_mem_level;
 210    int zlib_set_strategy;
 211 #endif
 212
 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    png_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.
 225                                */
 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
 229                                * allocated.
 230                                */
 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 */
 234 #endif
 235    png_size_t info_rowbytes;  /* Added in 1.5.4: cache of updated row bytes */
 236
 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 */
 241
 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 */
 245 #endif
 246
 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_ below ) */
 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 */
 260 #endif
 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 defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
 267    png_uint_16 filler;           /* filler bytes for pixel expansion */
 268 #endif
 269
 270 #if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
 271    defined(PNG_READ_ALPHA_MODE_SUPPORTED)
 272    png_byte background_gamma_type;
 273    png_fixed_point background_gamma;
 274    png_color_16 background;   /* background color in screen gamma space */
 275 #ifdef PNG_READ_GAMMA_SUPPORTED
 276    png_color_16 background_1; /* background normalized to gamma 1.0 */
 277 #endif
 278 #endif /* bKGD */
 279
 280 #ifdef PNG_WRITE_FLUSH_SUPPORTED
 281    png_flush_ptr output_flush_fn; /* Function for flushing output */
 282    png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */
 283    png_uint_32 flush_rows;    /* number of rows written since last flush */
 284 #endif
 285
 286 #ifdef PNG_READ_GAMMA_SUPPORTED
 287    int gamma_shift;      /* number of "insignificant" bits in 16-bit gamma */
 288    png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
 289
 290    png_bytep gamma_table;     /* gamma table for 8-bit depth files */
 291    png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
 292 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
 293    defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
 294    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
 295    png_bytep gamma_from_1;    /* converts from 1.0 to screen */
 296    png_bytep gamma_to_1;      /* converts from file to 1.0 */
 297    png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
 298    png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
 299 #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
 300 #endif
 301
 302 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
 303    png_color_8 sig_bit;       /* significant bits in each available channel */
 304 #endif
 305
 306 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
 307    png_color_8 shift;         /* shift for significant bit tranformation */
 308 #endif
 309
 310 #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
 311  || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
 312    png_bytep trans_alpha;           /* alpha values for paletted files */
 313    png_color_16 trans_color;  /* transparent color for non-paletted files */
 314 #endif
 315
 316    png_read_status_ptr read_row_fn;   /* called after each row is decoded */
 317    png_write_status_ptr write_row_fn; /* called after each row is encoded */
 318 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
 319    png_progressive_info_ptr info_fn; /* called after header data fully read */
 320    png_progressive_row_ptr row_fn;   /* called after a prog. row is decoded */
 321    png_progressive_end_ptr end_fn;   /* called after image is complete */
 322    png_bytep save_buffer_ptr;        /* current location in save_buffer */
 323    png_bytep save_buffer;            /* buffer for previously read data */
 324    png_bytep current_buffer_ptr;     /* current location in current_buffer */
 325    png_bytep current_buffer;         /* buffer for recently used data */
 326    png_uint_32 push_length;          /* size of current input chunk */
 327    png_uint_32 skip_length;          /* bytes to skip in input data */
 328    png_size_t save_buffer_size;      /* amount of data now in save_buffer */
 329    png_size_t save_buffer_max;       /* total size of save_buffer */
 330    png_size_t buffer_size;           /* total amount of available input data */
 331    png_size_t current_buffer_size;   /* amount of data now in current_buffer */
 332    int process_mode;                 /* what push library is currently doing */
 333    int cur_palette;                  /* current push library palette index */
 334
 335 #endif /* PROGRESSIVE_READ */
 336
 337 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
 338 /* For the Borland special 64K segment handler */
 339    png_bytepp offset_table_ptr;
 340    png_bytep offset_table;
 341    png_uint_16 offset_table_number;
 342    png_uint_16 offset_table_count;
 343    png_uint_16 offset_table_count_free;
 344 #endif
 345
 346 #ifdef PNG_READ_QUANTIZE_SUPPORTED
 347    png_bytep palette_lookup; /* lookup table for quantizing */
 348    png_bytep quantize_index; /* index translation for palette files */
 349 #endif
 350
 351 /* Options */
 352 #ifdef PNG_SET_OPTION_SUPPORTED
 353    png_byte options;           /* On/off state (up to 4 options) */
 354 #endif
 355
 356 #if PNG_LIBPNG_VER < 10700
 357 /* To do: remove this from libpng-1.7 */
 358 #ifdef PNG_TIME_RFC1123_SUPPORTED
 359    char time_buffer[29]; /* String to hold RFC 1123 time text */
 360 #endif
 361 #endif
 362
 363 /* New members added in libpng-1.0.6 */
 364
 365    png_uint_32 free_me;    /* flags items libpng is responsible for freeing */
 366
 367 #ifdef PNG_USER_CHUNKS_SUPPORTED
 368    png_voidp user_chunk_ptr;
 369 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
 370    png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
 371 #endif
 372 #endif
 373
 374 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
 375    int          unknown_default; /* As PNG_HANDLE_* */
 376    unsigned int num_chunk_list;  /* Number of entries in the list */
 377    png_bytep    chunk_list;      /* List of png_byte[5]; the textual chunk name
 378                                   * followed by a PNG_HANDLE_* byte */
 379 #endif
 380
 381 /* New members added in libpng-1.0.3 */
 382 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
 383    png_byte rgb_to_gray_status;
 384    /* Added in libpng 1.5.5 to record setting of coefficients: */
 385    png_byte rgb_to_gray_coefficients_set;
 386    /* These were changed from png_byte in libpng-1.0.6 */
 387    png_uint_16 rgb_to_gray_red_coeff;
 388    png_uint_16 rgb_to_gray_green_coeff;
 389    /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */
 390 #endif
 391
 392 /* New member added in libpng-1.0.4 (renamed in 1.0.9) */
 393 #if defined(PNG_MNG_FEATURES_SUPPORTED)
 394 /* Changed from png_byte to png_uint_32 at version 1.2.0 */
 395    png_uint_32 mng_features_permitted;
 396 #endif
 397
 398 /* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
 399 #ifdef PNG_MNG_FEATURES_SUPPORTED
 400    png_byte filter_type;
 401 #endif
 402
 403 /* New members added in libpng-1.2.0 */
 404
 405 /* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
 406 #ifdef PNG_USER_MEM_SUPPORTED
 407    png_voidp mem_ptr;             /* user supplied struct for mem functions */
 408    png_malloc_ptr malloc_fn;      /* function for allocating memory */
 409    png_free_ptr free_fn;          /* function for freeing memory */
 410 #endif
 411
 412 /* New member added in libpng-1.0.13 and 1.2.0 */
 413    png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */
 414
 415 #ifdef PNG_READ_QUANTIZE_SUPPORTED
 416 /* The following three members were added at version 1.0.14 and 1.2.4 */
 417    png_bytep quantize_sort;          /* working sort array */
 418    png_bytep index_to_palette;       /* where the original index currently is
 419                                         in the palette */
 420    png_bytep palette_to_index;       /* which original index points to this
 421                                          palette color */
 422 #endif
 423
 424 /* New members added in libpng-1.0.16 and 1.2.6 */
 425    png_byte compression_type;
 426
 427 #ifdef PNG_USER_LIMITS_SUPPORTED
 428    png_uint_32 user_width_max;
 429    png_uint_32 user_height_max;
 430
 431    /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
 432     * chunks that can be stored (0 means unlimited).
 433     */
 434    png_uint_32 user_chunk_cache_max;
 435
 436    /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
 437     * can occupy when decompressed.  0 means unlimited.
 438     */
 439    png_alloc_size_t user_chunk_malloc_max;
 440 #endif
 441
 442 /* New member added in libpng-1.0.25 and 1.2.17 */
 443 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
 444    /* Temporary storage for unknown chunk that the library doesn't recognize,
 445     * used while reading the chunk.
 446     */
 447    png_unknown_chunk unknown_chunk;
 448 #endif
 449
 450 /* New member added in libpng-1.2.26 */
 451   png_size_t old_big_row_buf_size;
 452
 453 #ifdef PNG_READ_SUPPORTED
 454 /* New member added in libpng-1.2.30 */
 455   png_bytep        read_buffer;      /* buffer for reading chunk data */
 456   png_alloc_size_t read_buffer_size; /* current size of the buffer */
 457 #endif
 458 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 459   uInt             IDAT_read_size;   /* limit on read buffer size for IDAT */
 460 #endif
 461
 462 #ifdef PNG_IO_STATE_SUPPORTED
 463 /* New member added in libpng-1.4.0 */
 464    png_uint_32 io_state;
 465 #endif
 466
 467 /* New member added in libpng-1.5.6 */
 468    png_bytep big_prev_row;
 469
 470 /* New member added in libpng-1.5.7 */
 471    void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
 472       png_bytep row, png_const_bytep prev_row);
 473
 474 #ifdef PNG_READ_SUPPORTED
 475 #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
 476    png_colorspace   colorspace;
 477 #endif
 478 #endif
 479 };
 480 #endif /* PNGSTRUCT_H */