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 1.5.0 [January 6, 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 png_jmpbuf;            /* 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    png_error_ptr warning_fn;  /* function for printing warnings */
  37    png_voidp error_ptr;       /* user supplied struct for error functions */
  38    png_rw_ptr write_data_fn;  /* function for writing output data */
  39    png_rw_ptr read_data_fn;   /* function for reading input data */
  40    png_voidp io_ptr;          /* ptr to application struct for I/O functions */
  41
  42 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
  43    png_user_transform_ptr read_user_transform_fn; /* user read transform */
  44 #endif
  45
  46 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
  47    png_user_transform_ptr write_user_transform_fn; /* user write transform */
  48 #endif
  49
  50 /* These were added in libpng-1.0.2 */
  51 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
  52 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
  53     defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
  54    png_voidp user_transform_ptr; /* user supplied struct for user transform */
  55    png_byte user_transform_depth;    /* bit depth of user transformed pixels */
  56    png_byte user_transform_channels; /* channels in user transformed pixels */
  57 #endif
  58 #endif
  59
  60    png_uint_32 mode;          /* tells us where we are in the PNG file */
  61    png_uint_32 flags;         /* flags indicating various things to libpng */
  62    png_uint_32 transformations; /* which transformations to perform */
  63
  64    z_stream zstream;          /* pointer to decompression structure (below) */
  65    png_bytep zbuf;            /* buffer for zlib */
  66    uInt zbuf_size;            /* size of zbuf (typically 65536) */
  67    int zlib_level;            /* holds zlib compression level */
  68    int zlib_method;           /* holds zlib compression method */
  69    int zlib_window_bits;      /* holds zlib compression window bits */
  70    int zlib_mem_level;        /* holds zlib compression memory level */
  71    int zlib_strategy;         /* holds zlib compression strategy */
  72
  73    png_uint_32 width;         /* width of image in pixels */
  74    png_uint_32 height;        /* height of image in pixels */
  75    png_uint_32 num_rows;      /* number of rows in current pass */
  76    png_uint_32 usr_width;     /* width of row at start of write */
  77    png_size_t rowbytes;       /* size of row in bytes */
  78    png_uint_32 iwidth;        /* width of current interlaced row in pixels */
  79    png_uint_32 row_number;    /* current row in interlace pass */
  80    png_bytep prev_row;        /* buffer to save previous (unfiltered) row */
  81    png_bytep row_buf;         /* buffer to save current (unfiltered) row */
  82    png_bytep sub_row;         /* buffer to save "sub" row when filtering */
  83    png_bytep up_row;          /* buffer to save "up" row when filtering */
  84    png_bytep avg_row;         /* buffer to save "avg" row when filtering */
  85    png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */
  86    png_row_info row_info;     /* used for transformation routines */
  87
  88    png_uint_32 idat_size;     /* current IDAT size for read */
  89    png_uint_32 crc;           /* current chunk CRC value */
  90    png_colorp palette;        /* palette from the input file */
  91    png_uint_16 num_palette;   /* number of color entries in palette */
  92    png_uint_16 num_trans;     /* number of transparency values */
  93    png_byte chunk_name[5];    /* null-terminated name of current chunk */
  94    png_byte compression;      /* file compression type (always 0) */
  95    png_byte filter;           /* file filter type (always 0) */
  96    png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
  97    png_byte pass;             /* current interlace pass (0 - 6) */
  98    png_byte do_filter;        /* row filter flags (see PNG_FILTER_ below ) */
  99    png_byte color_type;       /* color type of file */
 100    png_byte bit_depth;        /* bit depth of file */
 101    png_byte usr_bit_depth;    /* bit depth of users row */
 102    png_byte pixel_depth;      /* number of bits per pixel */
 103    png_byte channels;         /* number of channels in file */
 104    png_byte usr_channels;     /* channels at start of write */
 105    png_byte sig_bytes;        /* magic bytes read/written from start of file */
 106
 107 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
 108    png_uint_16 filler;           /* filler bytes for pixel expansion */
 109 #endif
 110
 111 #ifdef PNG_bKGD_SUPPORTED
 112    png_byte background_gamma_type;
 113    png_fixed_point background_gamma;
 114    png_color_16 background;   /* background color in screen gamma space */
 115 #ifdef PNG_READ_GAMMA_SUPPORTED
 116    png_color_16 background_1; /* background normalized to gamma 1.0 */
 117 #endif
 118 #endif /* PNG_bKGD_SUPPORTED */
 119
 120 #ifdef PNG_WRITE_FLUSH_SUPPORTED
 121    png_flush_ptr output_flush_fn; /* Function for flushing output */
 122    png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */
 123    png_uint_32 flush_rows;    /* number of rows written since last flush */
 124 #endif
 125
 126 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
 127    int gamma_shift;      /* number of "insignificant" bits in 16-bit gamma */
 128    png_fixed_point gamma;        /* file gamma value */
 129    png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
 130 #endif
 131
 132 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
 133    png_bytep gamma_table;     /* gamma table for 8-bit depth files */
 134    png_bytep gamma_from_1;    /* converts from 1.0 to screen */
 135    png_bytep gamma_to_1;      /* converts from file to 1.0 */
 136    png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
 137    png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
 138    png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
 139 #endif
 140
 141 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
 142    png_color_8 sig_bit;       /* significant bits in each available channel */
 143 #endif
 144
 145 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
 146    png_color_8 shift;         /* shift for significant bit tranformation */
 147 #endif
 148
 149 #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
 150  || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
 151    png_bytep trans_alpha;           /* alpha values for paletted files */
 152    png_color_16 trans_color;  /* transparent color for non-paletted files */
 153 #endif
 154
 155    png_read_status_ptr read_row_fn;   /* called after each row is decoded */
 156    png_write_status_ptr write_row_fn; /* called after each row is encoded */
 157 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
 158    png_progressive_info_ptr info_fn; /* called after header data fully read */
 159    png_progressive_row_ptr row_fn;   /* called after a prog. row is decoded */
 160    png_progressive_end_ptr end_fn;   /* called after image is complete */
 161    png_bytep save_buffer_ptr;        /* current location in save_buffer */
 162    png_bytep save_buffer;            /* buffer for previously read data */
 163    png_bytep current_buffer_ptr;     /* current location in current_buffer */
 164    png_bytep current_buffer;         /* buffer for recently used data */
 165    png_uint_32 push_length;          /* size of current input chunk */
 166    png_uint_32 skip_length;          /* bytes to skip in input data */
 167    png_size_t save_buffer_size;      /* amount of data now in save_buffer */
 168    png_size_t save_buffer_max;       /* total size of save_buffer */
 169    png_size_t buffer_size;           /* total amount of available input data */
 170    png_size_t current_buffer_size;   /* amount of data now in current_buffer */
 171    int process_mode;                 /* what push library is currently doing */
 172    int cur_palette;                  /* current push library palette index */
 173
 174 #  ifdef PNG_TEXT_SUPPORTED
 175      png_size_t current_text_size;   /* current size of text input data */
 176      png_size_t current_text_left;   /* how much text left to read in input */
 177      png_charp current_text;         /* current text chunk buffer */
 178      png_charp current_text_ptr;     /* current location in current_text */
 179 #  endif /* PNG_PROGRESSIVE_READ_SUPPORTED && PNG_TEXT_SUPPORTED */
 180
 181 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
 182
 183 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
 184 /* For the Borland special 64K segment handler */
 185    png_bytepp offset_table_ptr;
 186    png_bytep offset_table;
 187    png_uint_16 offset_table_number;
 188    png_uint_16 offset_table_count;
 189    png_uint_16 offset_table_count_free;
 190 #endif
 191
 192 #ifdef PNG_READ_QUANTIZE_SUPPORTED
 193    png_bytep palette_lookup; /* lookup table for quantizing */
 194    png_bytep quantize_index; /* index translation for palette files */
 195 #endif
 196
 197 #if defined(PNG_READ_QUANTIZE_SUPPORTED) || defined(PNG_hIST_SUPPORTED)
 198    png_uint_16p hist;                /* histogram */
 199 #endif
 200
 201 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
 202    png_byte heuristic_method;        /* heuristic for row filter selection */
 203    png_byte num_prev_filters;        /* number of weights for previous rows */
 204    png_bytep prev_filters;           /* filter type(s) of previous row(s) */
 205    png_uint_16p filter_weights;      /* weight(s) for previous line(s) */
 206    png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */
 207    png_uint_16p filter_costs;        /* relative filter calculation cost */
 208    png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */
 209 #endif
 210
 211 #ifdef PNG_TIME_RFC1123_SUPPORTED
 212    png_charp time_buffer; /* String to hold RFC 1123 time text */
 213 #endif
 214
 215 /* New members added in libpng-1.0.6 */
 216
 217    png_uint_32 free_me;    /* flags items libpng is responsible for freeing */
 218
 219 #ifdef PNG_USER_CHUNKS_SUPPORTED
 220    png_voidp user_chunk_ptr;
 221    png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
 222 #endif
 223
 224 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
 225    int num_chunk_list;
 226    png_bytep chunk_list;
 227 #endif
 228
 229 /* New members added in libpng-1.0.3 */
 230 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
 231    png_byte rgb_to_gray_status;
 232    /* These were changed from png_byte in libpng-1.0.6 */
 233    png_uint_16 rgb_to_gray_red_coeff;
 234    png_uint_16 rgb_to_gray_green_coeff;
 235    png_uint_16 rgb_to_gray_blue_coeff;
 236 #endif
 237
 238 /* New member added in libpng-1.0.4 (renamed in 1.0.9) */
 239 #if defined(PNG_MNG_FEATURES_SUPPORTED) || \
 240     defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
 241     defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
 242 /* Changed from png_byte to png_uint_32 at version 1.2.0 */
 243    png_uint_32 mng_features_permitted;
 244 #endif
 245
 246 /* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
 247 #ifdef PNG_MNG_FEATURES_SUPPORTED
 248    png_byte filter_type;
 249 #endif
 250
 251 /* New members added in libpng-1.2.0 */
 252
 253 /* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
 254 #ifdef PNG_USER_MEM_SUPPORTED
 255    png_voidp mem_ptr;             /* user supplied struct for mem functions */
 256    png_malloc_ptr malloc_fn;      /* function for allocating memory */
 257    png_free_ptr free_fn;          /* function for freeing memory */
 258 #endif
 259
 260 /* New member added in libpng-1.0.13 and 1.2.0 */
 261    png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */
 262
 263 #ifdef PNG_READ_QUANTIZE_SUPPORTED
 264 /* The following three members were added at version 1.0.14 and 1.2.4 */
 265    png_bytep quantize_sort;          /* working sort array */
 266    png_bytep index_to_palette;       /* where the original index currently is
 267                                         in the palette */
 268    png_bytep palette_to_index;       /* which original index points to this
 269                                          palette color */
 270 #endif
 271
 272 /* New members added in libpng-1.0.16 and 1.2.6 */
 273    png_byte compression_type;
 274
 275 #ifdef PNG_USER_LIMITS_SUPPORTED
 276    png_uint_32 user_width_max;
 277    png_uint_32 user_height_max;
 278
 279    /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
 280     * chunks that can be stored (0 means unlimited).
 281     */
 282    png_uint_32 user_chunk_cache_max;
 283
 284    /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
 285     * can occupy when decompressed.  0 means unlimited.
 286     */
 287    png_alloc_size_t user_chunk_malloc_max;
 288 #endif
 289
 290 /* New member added in libpng-1.0.25 and 1.2.17 */
 291 #ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
 292    /* Storage for unknown chunk that the library doesn't recognize. */
 293    png_unknown_chunk unknown_chunk;
 294 #endif
 295
 296 /* New members added in libpng-1.2.26 */
 297   png_size_t old_big_row_buf_size;
 298   png_size_t old_prev_row_size;
 299
 300 /* New member added in libpng-1.2.30 */
 301   png_charp chunkdata;  /* buffer for reading chunk data */
 302
 303 #ifdef PNG_IO_STATE_SUPPORTED
 304 /* New member added in libpng-1.4.0 */
 305    png_uint_32 io_state;
 306 #endif
 307 };
 308 #endif /* PNGSTRUCT_H */