src/png/pngstruct.h

   1
   2 /* pngstruct.h - header file for PNG reference library
   3  *
   4  * Copyright (c) 1998-2011 Glenn Randers-Pehrson
   5  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
   6  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
   7  *
   8  * Last changed in libpng 1.5.5 [September 22, 2011]
   9  *
  10  * This code is released under the libpng license.
  11  * For conditions of distribution and use, see the disclaimer
  12  * and license in png.h
  13  */
  14
  15 /* The structure that holds the information to read and write PNG files.
  16  * The only people who need to care about what is inside of this are the
  17  * people who will be modifying the library for their own special needs.
  18  * It should NOT be accessed directly by an application.
  19  */
  20
  21 #ifndef PNGSTRUCT_H
  22 #define PNGSTRUCT_H
  23 /* zlib.h defines the structure z_stream, an instance of which is included
  24  * in this structure and is required for decompressing the LZ compressed
  25  * data in PNG files.
  26  */
  27 #include "zlib.h"
  28
  29 struct png_struct_def
  30 {
  31 #ifdef PNG_SETJMP_SUPPORTED
  32    jmp_buf longjmp_buffer;    /* used in png_error */
  33    png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */
  34 #endif
  35    png_error_ptr error_fn;    /* function for printing errors and aborting */
  36 #ifdef PNG_WARNINGS_SUPPORTED
  37    png_error_ptr warning_fn;  /* function for printing warnings */
  38 #endif
  39    png_voidp error_ptr;       /* user supplied struct for error functions */
  40    png_rw_ptr write_data_fn;  /* function for writing output data */
  41    png_rw_ptr read_data_fn;   /* function for reading input data */
  42    png_voidp io_ptr;          /* ptr to application struct for I/O functions */
  43
  44 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
  45    png_user_transform_ptr read_user_transform_fn; /* user read transform */
  46 #endif
  47
  48 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
  49    png_user_transform_ptr write_user_transform_fn; /* user write transform */
  50 #endif
  51
  52 /* These were added in libpng-1.0.2 */
  53 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
  54 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
  55     defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
  56    png_voidp user_transform_ptr; /* user supplied struct for user transform */
  57    png_byte user_transform_depth;    /* bit depth of user transformed pixels */
  58    png_byte user_transform_channels; /* channels in user transformed pixels */
  59 #endif
  60 #endif
  61
  62    png_uint_32 mode;          /* tells us where we are in the PNG file */
  63    png_uint_32 flags;         /* flags indicating various things to libpng */
  64    png_uint_32 transformations; /* which transformations to perform */
  65
  66    z_stream zstream;          /* pointer to decompression structure (below) */
  67    png_bytep zbuf;            /* buffer for zlib */
  68    uInt zbuf_size;            /* size of zbuf (typically 65536) */
  69 #ifdef PNG_WRITE_SUPPORTED
  70
  71 /* Added in 1.5.4: state to keep track of whether the zstream has been
  72  * initialized and if so whether it is for IDAT or some other chunk.
  73  */
  74 #define PNG_ZLIB_UNINITIALIZED 0
  75 #define PNG_ZLIB_FOR_IDAT      1
  76 #define PNG_ZLIB_FOR_TEXT      2 /* anything other than IDAT */
  77 #define PNG_ZLIB_USE_MASK      3 /* bottom two bits */
  78 #define PNG_ZLIB_IN_USE        4 /* a flag value */
  79
  80    png_uint_32 zlib_state;       /* State of zlib initialization */
  81 /* End of material added at libpng 1.5.4 */
  82
  83    int zlib_level;            /* holds zlib compression level */
  84    int zlib_method;           /* holds zlib compression method */
  85    int zlib_window_bits;      /* holds zlib compression window bits */
  86    int zlib_mem_level;        /* holds zlib compression memory level */
  87    int zlib_strategy;         /* holds zlib compression strategy */
  88 #endif
  89 /* Added at libpng 1.5.4 */
  90 #if defined(PNG_WRITE_COMPRESSED_TEXT_SUPPORTED) || \
  91     defined(PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED)
  92    int zlib_text_level;            /* holds zlib compression level */
  93    int zlib_text_method;           /* holds zlib compression method */
  94    int zlib_text_window_bits;      /* holds zlib compression window bits */
  95    int zlib_text_mem_level;        /* holds zlib compression memory level */
  96    int zlib_text_strategy;         /* holds zlib compression strategy */
  97 #endif
  98 /* End of material added at libpng 1.5.4 */
  99
 100    png_uint_32 width;         /* width of image in pixels */
 101    png_uint_32 height;        /* height of image in pixels */
 102    png_uint_32 num_rows;      /* number of rows in current pass */
 103    png_uint_32 usr_width;     /* width of row at start of write */
 104    png_size_t rowbytes;       /* size of row in bytes */
 105    png_uint_32 iwidth;        /* width of current interlaced row in pixels */
 106    png_uint_32 row_number;    /* current row in interlace pass */
 107    png_uint_32 chunk_name;    /* PNG_CHUNK() id of current chunk */
 108    png_bytep prev_row;        /* buffer to save previous (unfiltered) row.
 109                                * This is a pointer into big_prev_row
 110                                */
 111    png_bytep row_buf;         /* buffer to save current (unfiltered) row.
 112                                * This is a pointer into big_row_buf
 113                                */
 114    png_bytep sub_row;         /* buffer to save "sub" row when filtering */
 115    png_bytep up_row;          /* buffer to save "up" row when filtering */
 116    png_bytep avg_row;         /* buffer to save "avg" row when filtering */
 117    png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */
 118    png_size_t info_rowbytes;  /* Added in 1.5.4: cache of updated row bytes */
 119
 120    png_uint_32 idat_size;     /* current IDAT size for read */
 121    png_uint_32 crc;           /* current chunk CRC value */
 122    png_colorp palette;        /* palette from the input file */
 123    png_uint_16 num_palette;   /* number of color entries in palette */
 124    png_uint_16 num_trans;     /* number of transparency values */
 125    png_byte compression;      /* file compression type (always 0) */
 126    png_byte filter;           /* file filter type (always 0) */
 127    png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
 128    png_byte pass;             /* current interlace pass (0 - 6) */
 129    png_byte do_filter;        /* row filter flags (see PNG_FILTER_ below ) */
 130    png_byte color_type;       /* color type of file */
 131    png_byte bit_depth;        /* bit depth of file */
 132    png_byte usr_bit_depth;    /* bit depth of users row: write only */
 133    png_byte pixel_depth;      /* number of bits per pixel */
 134    png_byte channels;         /* number of channels in file */
 135    png_byte usr_channels;     /* channels at start of write: write only */
 136    png_byte sig_bytes;        /* magic bytes read/written from start of file */
 137    png_byte maximum_pixel_depth;
 138                               /* pixel depth used for the row buffers */
 139    png_byte transformed_pixel_depth;
 140                               /* pixel depth after read/write transforms */
 141    png_byte io_chunk_string[5];
 142                               /* string name of chunk */
 143
 144 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
 145    png_uint_16 filler;           /* filler bytes for pixel expansion */
 146 #endif
 147
 148 #if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
 149    defined(PNG_READ_ALPHA_MODE_SUPPORTED)
 150    png_byte background_gamma_type;
 151    png_fixed_point background_gamma;
 152    png_color_16 background;   /* background color in screen gamma space */
 153 #ifdef PNG_READ_GAMMA_SUPPORTED
 154    png_color_16 background_1; /* background normalized to gamma 1.0 */
 155 #endif
 156 #endif /* PNG_bKGD_SUPPORTED */
 157
 158 #ifdef PNG_WRITE_FLUSH_SUPPORTED
 159    png_flush_ptr output_flush_fn; /* Function for flushing output */
 160    png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */
 161    png_uint_32 flush_rows;    /* number of rows written since last flush */
 162 #endif
 163
 164 #ifdef PNG_READ_GAMMA_SUPPORTED
 165    int gamma_shift;      /* number of "insignificant" bits in 16-bit gamma */
 166    png_fixed_point gamma;        /* file gamma value */
 167    png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
 168
 169    png_bytep gamma_table;     /* gamma table for 8-bit depth files */
 170    png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
 171 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
 172    defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
 173    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
 174    png_bytep gamma_from_1;    /* converts from 1.0 to screen */
 175    png_bytep gamma_to_1;      /* converts from file to 1.0 */
 176    png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
 177    png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
 178 #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
 179 #endif
 180
 181 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
 182    png_color_8 sig_bit;       /* significant bits in each available channel */
 183 #endif
 184
 185 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
 186    png_color_8 shift;         /* shift for significant bit tranformation */
 187 #endif
 188
 189 #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
 190  || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
 191    png_bytep trans_alpha;           /* alpha values for paletted files */
 192    png_color_16 trans_color;  /* transparent color for non-paletted files */
 193 #endif
 194
 195    png_read_status_ptr read_row_fn;   /* called after each row is decoded */
 196    png_write_status_ptr write_row_fn; /* called after each row is encoded */
 197 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
 198    png_progressive_info_ptr info_fn; /* called after header data fully read */
 199    png_progressive_row_ptr row_fn;   /* called after a prog. row is decoded */
 200    png_progressive_end_ptr end_fn;   /* called after image is complete */
 201    png_bytep save_buffer_ptr;        /* current location in save_buffer */
 202    png_bytep save_buffer;            /* buffer for previously read data */
 203    png_bytep current_buffer_ptr;     /* current location in current_buffer */
 204    png_bytep current_buffer;         /* buffer for recently used data */
 205    png_uint_32 push_length;          /* size of current input chunk */
 206    png_uint_32 skip_length;          /* bytes to skip in input data */
 207    png_size_t save_buffer_size;      /* amount of data now in save_buffer */
 208    png_size_t save_buffer_max;       /* total size of save_buffer */
 209    png_size_t buffer_size;           /* total amount of available input data */
 210    png_size_t current_buffer_size;   /* amount of data now in current_buffer */
 211    int process_mode;                 /* what push library is currently doing */
 212    int cur_palette;                  /* current push library palette index */
 213
 214 #  ifdef PNG_TEXT_SUPPORTED
 215      png_size_t current_text_size;   /* current size of text input data */
 216      png_size_t current_text_left;   /* how much text left to read in input */
 217      png_charp current_text;         /* current text chunk buffer */
 218      png_charp current_text_ptr;     /* current location in current_text */
 219 #  endif /* PNG_PROGRESSIVE_READ_SUPPORTED && PNG_TEXT_SUPPORTED */
 220
 221 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
 222
 223 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
 224 /* For the Borland special 64K segment handler */
 225    png_bytepp offset_table_ptr;
 226    png_bytep offset_table;
 227    png_uint_16 offset_table_number;
 228    png_uint_16 offset_table_count;
 229    png_uint_16 offset_table_count_free;
 230 #endif
 231
 232 #ifdef PNG_READ_QUANTIZE_SUPPORTED
 233    png_bytep palette_lookup; /* lookup table for quantizing */
 234    png_bytep quantize_index; /* index translation for palette files */
 235 #endif
 236
 237 #if defined(PNG_READ_QUANTIZE_SUPPORTED) || defined(PNG_hIST_SUPPORTED)
 238    png_uint_16p hist;                /* histogram */
 239 #endif
 240
 241 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
 242    png_byte heuristic_method;        /* heuristic for row filter selection */
 243    png_byte num_prev_filters;        /* number of weights for previous rows */
 244    png_bytep prev_filters;           /* filter type(s) of previous row(s) */
 245    png_uint_16p filter_weights;      /* weight(s) for previous line(s) */
 246    png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */
 247    png_uint_16p filter_costs;        /* relative filter calculation cost */
 248    png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */
 249 #endif
 250
 251 #ifdef PNG_TIME_RFC1123_SUPPORTED
 252    char time_buffer[29]; /* String to hold RFC 1123 time text */
 253 #endif
 254
 255 /* New members added in libpng-1.0.6 */
 256
 257    png_uint_32 free_me;    /* flags items libpng is responsible for freeing */
 258
 259 #ifdef PNG_USER_CHUNKS_SUPPORTED
 260    png_voidp user_chunk_ptr;
 261    png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
 262 #endif
 263
 264 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 265    int num_chunk_list;
 266    png_bytep chunk_list;
 267 #endif
 268
 269 #ifdef PNG_READ_sRGB_SUPPORTED
 270    /* Added in 1.5.5 to record an sRGB chunk in the png. */
 271    png_byte is_sRGB;
 272 #endif
 273
 274 /* New members added in libpng-1.0.3 */
 275 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
 276    png_byte rgb_to_gray_status;
 277    /* Added in libpng 1.5.5 to record setting of coefficients: */
 278    png_byte rgb_to_gray_coefficients_set;
 279    /* These were changed from png_byte in libpng-1.0.6 */
 280    png_uint_16 rgb_to_gray_red_coeff;
 281    png_uint_16 rgb_to_gray_green_coeff;
 282    /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */
 283 #endif
 284
 285 /* New member added in libpng-1.0.4 (renamed in 1.0.9) */
 286 #if defined(PNG_MNG_FEATURES_SUPPORTED) || \
 287     defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
 288     defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
 289 /* Changed from png_byte to png_uint_32 at version 1.2.0 */
 290    png_uint_32 mng_features_permitted;
 291 #endif
 292
 293 /* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
 294 #ifdef PNG_MNG_FEATURES_SUPPORTED
 295    png_byte filter_type;
 296 #endif
 297
 298 /* New members added in libpng-1.2.0 */
 299
 300 /* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
 301 #ifdef PNG_USER_MEM_SUPPORTED
 302    png_voidp mem_ptr;             /* user supplied struct for mem functions */
 303    png_malloc_ptr malloc_fn;      /* function for allocating memory */
 304    png_free_ptr free_fn;          /* function for freeing memory */
 305 #endif
 306
 307 /* New member added in libpng-1.0.13 and 1.2.0 */
 308    png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */
 309
 310 #ifdef PNG_READ_QUANTIZE_SUPPORTED
 311 /* The following three members were added at version 1.0.14 and 1.2.4 */
 312    png_bytep quantize_sort;          /* working sort array */
 313    png_bytep index_to_palette;       /* where the original index currently is
 314                                         in the palette */
 315    png_bytep palette_to_index;       /* which original index points to this
 316                                          palette color */
 317 #endif
 318
 319 /* New members added in libpng-1.0.16 and 1.2.6 */
 320    png_byte compression_type;
 321
 322 #ifdef PNG_USER_LIMITS_SUPPORTED
 323    png_uint_32 user_width_max;
 324    png_uint_32 user_height_max;
 325
 326    /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
 327     * chunks that can be stored (0 means unlimited).
 328     */
 329    png_uint_32 user_chunk_cache_max;
 330
 331    /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
 332     * can occupy when decompressed.  0 means unlimited.
 333     */
 334    png_alloc_size_t user_chunk_malloc_max;
 335 #endif
 336
 337 /* New member added in libpng-1.0.25 and 1.2.17 */
 338 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
 339    /* Storage for unknown chunk that the library doesn't recognize. */
 340    png_unknown_chunk unknown_chunk;
 341 #endif
 342
 343 /* New member added in libpng-1.2.26 */
 344   png_size_t old_big_row_buf_size;
 345
 346 /* New member added in libpng-1.2.30 */
 347   png_charp chunkdata;  /* buffer for reading chunk data */
 348
 349 #ifdef PNG_IO_STATE_SUPPORTED
 350 /* New member added in libpng-1.4.0 */
 351    png_uint_32 io_state;
 352 #endif
 353
 354 /* New member added in libpng-1.5.6 */
 355    png_bytep big_prev_row;
 356
 357    void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
 358       png_bytep row, png_const_bytep prev_row);
 359 };
 360 #endif /* PNGSTRUCT_H */