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      1 
      2 /* pngstruct.h - header file for PNG reference library
      3  *
      4  * Copyright (c) 1998-2013 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 1.6.1 [March 28, 2013]
      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 #ifndef ZLIB_CONST
     28    /* We must ensure that zlib uses 'const' in declarations. */
     29 #  define ZLIB_CONST
     30 #endif
     31 #include "zlib.h"
     32 #ifdef const
     33    /* zlib.h sometimes #defines const to nothing, undo this. */
     34 #  undef const
     35 #endif
     36 
     37 /* zlib.h has mediocre z_const use before 1.2.6, this stuff is for compatibility
     38  * with older builds.
     39  */
     40 #if ZLIB_VERNUM < 0x1260
     41 #  define PNGZ_MSG_CAST(s) png_constcast(char*,s)
     42 #  define PNGZ_INPUT_CAST(b) png_constcast(png_bytep,b)
     43 #else
     44 #  define PNGZ_MSG_CAST(s) (s)
     45 #  define PNGZ_INPUT_CAST(b) (b)
     46 #endif
     47 
     48 /* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib
     49  * can handle at once.  This type need be no larger than 16 bits (so maximum of
     50  * 65535), this define allows us to discover how big it is, but limited by the
     51  * maximuum for png_size_t.  The value can be overriden in a library build
     52  * (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably
     53  * lower value (e.g. 255 works).  A lower value may help memory usage (slightly)
     54  * and may even improve performance on some systems (and degrade it on others.)
     55  */
     56 #ifndef ZLIB_IO_MAX
     57 #  define ZLIB_IO_MAX ((uInt)-1)
     58 #endif
     59 
     60 #ifdef PNG_WRITE_SUPPORTED
     61 /* The type of a compression buffer list used by the write code. */
     62 typedef struct png_compression_buffer
     63 {
     64    struct png_compression_buffer *next;
     65    png_byte                       output[1]; /* actually zbuf_size */
     66 } png_compression_buffer, *png_compression_bufferp;
     67 
     68 #define PNG_COMPRESSION_BUFFER_SIZE(pp)\
     69    (offsetof(png_compression_buffer, output) + (pp)->zbuffer_size)
     70 #endif
     71 
     72 /* Colorspace support; structures used in png_struct, png_info and in internal
     73  * functions to hold and communicate information about the color space.
     74  *
     75  * PNG_COLORSPACE_SUPPORTED is only required if the application will perform
     76  * colorspace corrections, otherwise all the colorspace information can be
     77  * skipped and the size of libpng can be reduced (significantly) by compiling
     78  * out the colorspace support.
     79  */
     80 #ifdef PNG_COLORSPACE_SUPPORTED
     81 /* The chromaticities of the red, green and blue colorants and the chromaticity
     82  * of the corresponding white point (i.e. of rgb(1.0,1.0,1.0)).
     83  */
     84 typedef struct png_xy
     85 {
     86    png_fixed_point redx, redy;
     87    png_fixed_point greenx, greeny;
     88    png_fixed_point bluex, bluey;
     89    png_fixed_point whitex, whitey;
     90 } png_xy;
     91 
     92 /* The same data as above but encoded as CIE XYZ values.  When this data comes
     93  * from chromaticities the sum of the Y values is assumed to be 1.0
     94  */
     95 typedef struct png_XYZ
     96 {
     97    png_fixed_point red_X, red_Y, red_Z;
     98    png_fixed_point green_X, green_Y, green_Z;
     99    png_fixed_point blue_X, blue_Y, blue_Z;
    100 } png_XYZ;
    101 #endif /* COLORSPACE */
    102 
    103 #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
    104 /* A colorspace is all the above plus, potentially, profile information,
    105  * however at present libpng does not use the profile internally so it is only
    106  * stored in the png_info struct (if iCCP is supported.)  The rendering intent
    107  * is retained here and is checked.
    108  *
    109  * The file gamma encoding information is also stored here and gamma correction
    110  * is done by libpng, whereas color correction must currently be done by the
    111  * application.
    112  */
    113 typedef struct png_colorspace
    114 {
    115 #ifdef PNG_GAMMA_SUPPORTED
    116    png_fixed_point gamma;        /* File gamma */
    117 #endif
    118 
    119 #ifdef PNG_COLORSPACE_SUPPORTED
    120    png_xy      end_points_xy;    /* End points as chromaticities */
    121    png_XYZ     end_points_XYZ;   /* End points as CIE XYZ colorant values */
    122    png_uint_16 rendering_intent; /* Rendering intent of a profile */
    123 #endif
    124 
    125    /* Flags are always defined to simplify the code. */
    126    png_uint_16 flags;            /* As defined below */
    127 } png_colorspace, * PNG_RESTRICT png_colorspacerp;
    128 
    129 typedef const png_colorspace * PNG_RESTRICT png_const_colorspacerp;
    130 
    131 /* General flags for the 'flags' field */
    132 #define PNG_COLORSPACE_HAVE_GAMMA           0x0001
    133 #define PNG_COLORSPACE_HAVE_ENDPOINTS       0x0002
    134 #define PNG_COLORSPACE_HAVE_INTENT          0x0004
    135 #define PNG_COLORSPACE_FROM_gAMA            0x0008
    136 #define PNG_COLORSPACE_FROM_cHRM            0x0010
    137 #define PNG_COLORSPACE_FROM_sRGB            0x0020
    138 #define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0040
    139 #define PNG_COLORSPACE_MATCHES_sRGB         0x0080 /* exact match on profile */
    140 #define PNG_COLORSPACE_INVALID              0x8000
    141 #define PNG_COLORSPACE_CANCEL(flags)        (0xffff ^ (flags))
    142 #endif /* COLORSPACE || GAMMA */
    143 
    144 #ifdef PNG_INDEX_SUPPORTED
    145 /* png_line_index_struct records an index point, where we impose an index point
    146  * to be located at the beginning of a line for simplifying the implementation.
    147  */
    148 typedef struct png_line_index_struct
    149 {
    150    // state of the lz decoder
    151    z_streamp   z_state;
    152 
    153    // the IDAT header position of the chunk, which the index point is in
    154    png_uint_32  stream_idat_position;
    155 
    156    // we intend to record the offset of the index point in the chunk,
    157    // but we record the number of remaining bytes in the chunk after the
    158    // index point. That's because PNG processes a chunk this way.
    159    png_uint_32  bytes_left_in_idat;
    160 
    161    // decompressed data of the previous row
    162    png_bytep   prev_row;
    163 } png_line_index;
    164 typedef png_line_index FAR * png_line_indexp;
    165 
    166 typedef struct png_index_struct
    167 {
    168    // A temporary variable used when we build the index. The variable records
    169    // the IDAT header position of the last chunk read in so far.
    170    png_uint_32  stream_idat_position;
    171 
    172    // line index information about each passes
    173 
    174    // the number of index points in each pass
    175    png_uint_32  size[7];
    176 
    177    // the line span of two index points of each pass
    178    png_uint_32  step[7];
    179 
    180    // the index points of each pass
    181    png_line_indexp  *pass_line_index[7];
    182 } png_index;
    183 typedef png_index FAR * png_indexp;
    184 
    185 #define INDEX_SAMPLE_SIZE 254
    186 #endif
    187 
    188 struct png_struct_def
    189 {
    190 #ifdef PNG_SETJMP_SUPPORTED
    191    jmp_buf jmp_buf_local;     /* New name in 1.6.0 for jmp_buf in png_struct */
    192    png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */
    193    jmp_buf *jmp_buf_ptr;      /* passed to longjmp_fn */
    194    size_t jmp_buf_size;       /* size of the above, if allocated */
    195 #endif
    196    png_error_ptr error_fn;    /* function for printing errors and aborting */
    197 #ifdef PNG_WARNINGS_SUPPORTED
    198    png_error_ptr warning_fn;  /* function for printing warnings */
    199 #endif
    200    png_voidp error_ptr;       /* user supplied struct for error functions */
    201    png_rw_ptr write_data_fn;  /* function for writing output data */
    202    png_rw_ptr read_data_fn;   /* function for reading input data */
    203 #ifdef PNG_INDEX_SUPPORTED
    204    png_seek_ptr seek_data_fn; /* function for seeking input data */
    205 #endif
    206    png_voidp io_ptr;          /* ptr to application struct for I/O functions */
    207 
    208 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
    209    png_user_transform_ptr read_user_transform_fn; /* user read transform */
    210 #endif
    211 
    212 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
    213    png_user_transform_ptr write_user_transform_fn; /* user write transform */
    214 #endif
    215 
    216 /* These were added in libpng-1.0.2 */
    217 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
    218 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
    219     defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
    220    png_voidp user_transform_ptr; /* user supplied struct for user transform */
    221    png_byte user_transform_depth;    /* bit depth of user transformed pixels */
    222    png_byte user_transform_channels; /* channels in user transformed pixels */
    223 #endif
    224 #endif
    225 
    226    png_uint_32 mode;          /* tells us where we are in the PNG file */
    227    png_uint_32 flags;         /* flags indicating various things to libpng */
    228    png_uint_32 transformations; /* which transformations to perform */
    229 
    230    png_uint_32 zowner;        /* ID (chunk type) of zstream owner, 0 if none */
    231    z_stream    zstream;       /* decompression structure */
    232 
    233 #ifdef PNG_WRITE_SUPPORTED
    234    png_compression_bufferp zbuffer_list; /* Created on demand during write */
    235    uInt                    zbuffer_size; /* size of the actual buffer */
    236 
    237    int zlib_level;            /* holds zlib compression level */
    238    int zlib_method;           /* holds zlib compression method */
    239    int zlib_window_bits;      /* holds zlib compression window bits */
    240    int zlib_mem_level;        /* holds zlib compression memory level */
    241    int zlib_strategy;         /* holds zlib compression strategy */
    242 #endif
    243 /* Added at libpng 1.5.4 */
    244 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
    245    int zlib_text_level;            /* holds zlib compression level */
    246    int zlib_text_method;           /* holds zlib compression method */
    247    int zlib_text_window_bits;      /* holds zlib compression window bits */
    248    int zlib_text_mem_level;        /* holds zlib compression memory level */
    249    int zlib_text_strategy;         /* holds zlib compression strategy */
    250 #endif
    251 /* End of material added at libpng 1.5.4 */
    252 /* Added at libpng 1.6.0 */
    253 #ifdef PNG_WRITE_SUPPORTED
    254    int zlib_set_level;        /* Actual values set into the zstream on write */
    255    int zlib_set_method;
    256    int zlib_set_window_bits;
    257    int zlib_set_mem_level;
    258    int zlib_set_strategy;
    259 #endif
    260 
    261    png_uint_32 width;         /* width of image in pixels */
    262    png_uint_32 height;        /* height of image in pixels */
    263    png_uint_32 num_rows;      /* number of rows in current pass */
    264    png_uint_32 usr_width;     /* width of row at start of write */
    265    png_size_t rowbytes;       /* size of row in bytes */
    266    png_uint_32 iwidth;        /* width of current interlaced row in pixels */
    267    png_uint_32 row_number;    /* current row in interlace pass */
    268    png_uint_32 chunk_name;    /* PNG_CHUNK() id of current chunk */
    269    png_bytep prev_row;        /* buffer to save previous (unfiltered) row.
    270                                * This is a pointer into big_prev_row
    271                                */
    272    png_bytep row_buf;         /* buffer to save current (unfiltered) row.
    273                                * This is a pointer into big_row_buf
    274                                */
    275 #ifdef PNG_WRITE_SUPPORTED
    276    png_bytep sub_row;         /* buffer to save "sub" row when filtering */
    277    png_bytep up_row;          /* buffer to save "up" row when filtering */
    278    png_bytep avg_row;         /* buffer to save "avg" row when filtering */
    279    png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */
    280 #endif
    281    png_size_t info_rowbytes;  /* Added in 1.5.4: cache of updated row bytes */
    282 
    283    png_uint_32 idat_size;     /* current IDAT size for read */
    284    png_uint_32 crc;           /* current chunk CRC value */
    285    png_colorp palette;        /* palette from the input file */
    286    png_uint_16 num_palette;   /* number of color entries in palette */
    287 
    288 /* Added at libpng-1.5.10 */
    289 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
    290    int num_palette_max;       /* maximum palette index found in IDAT */
    291 #endif
    292 
    293    png_uint_16 num_trans;     /* number of transparency values */
    294    png_byte compression;      /* file compression type (always 0) */
    295    png_byte filter;           /* file filter type (always 0) */
    296    png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
    297    png_byte pass;             /* current interlace pass (0 - 6) */
    298    png_byte do_filter;        /* row filter flags (see PNG_FILTER_ below ) */
    299    png_byte color_type;       /* color type of file */
    300    png_byte bit_depth;        /* bit depth of file */
    301    png_byte usr_bit_depth;    /* bit depth of users row: write only */
    302    png_byte pixel_depth;      /* number of bits per pixel */
    303    png_byte channels;         /* number of channels in file */
    304 #ifdef PNG_WRITE_SUPPORTED
    305    png_byte usr_channels;     /* channels at start of write: write only */
    306 #endif
    307    png_byte sig_bytes;        /* magic bytes read/written from start of file */
    308    png_byte maximum_pixel_depth;
    309                               /* pixel depth used for the row buffers */
    310    png_byte transformed_pixel_depth;
    311                               /* pixel depth after read/write transforms */
    312 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
    313    png_uint_16 filler;           /* filler bytes for pixel expansion */
    314 #endif
    315 
    316 #if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
    317    defined(PNG_READ_ALPHA_MODE_SUPPORTED)
    318    png_byte background_gamma_type;
    319    png_fixed_point background_gamma;
    320    png_color_16 background;   /* background color in screen gamma space */
    321 #ifdef PNG_READ_GAMMA_SUPPORTED
    322    png_color_16 background_1; /* background normalized to gamma 1.0 */
    323 #endif
    324 #endif /* PNG_bKGD_SUPPORTED */
    325 
    326 #ifdef PNG_WRITE_FLUSH_SUPPORTED
    327    png_flush_ptr output_flush_fn; /* Function for flushing output */
    328    png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */
    329    png_uint_32 flush_rows;    /* number of rows written since last flush */
    330 #endif
    331 
    332 #ifdef PNG_READ_GAMMA_SUPPORTED
    333    int gamma_shift;      /* number of "insignificant" bits in 16-bit gamma */
    334    png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
    335 
    336    png_bytep gamma_table;     /* gamma table for 8-bit depth files */
    337    png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
    338 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
    339    defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
    340    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
    341    png_bytep gamma_from_1;    /* converts from 1.0 to screen */
    342    png_bytep gamma_to_1;      /* converts from file to 1.0 */
    343    png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
    344    png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
    345 #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
    346 #endif
    347 
    348 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
    349    png_color_8 sig_bit;       /* significant bits in each available channel */
    350 #endif
    351 
    352 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
    353    png_color_8 shift;         /* shift for significant bit tranformation */
    354 #endif
    355 
    356 #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
    357  || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
    358    png_bytep trans_alpha;           /* alpha values for paletted files */
    359    png_color_16 trans_color;  /* transparent color for non-paletted files */
    360 #endif
    361 
    362    png_read_status_ptr read_row_fn;   /* called after each row is decoded */
    363    png_write_status_ptr write_row_fn; /* called after each row is encoded */
    364 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
    365    png_progressive_info_ptr info_fn; /* called after header data fully read */
    366    png_progressive_row_ptr row_fn;   /* called after a prog. row is decoded */
    367    png_progressive_end_ptr end_fn;   /* called after image is complete */
    368    png_bytep save_buffer_ptr;        /* current location in save_buffer */
    369    png_bytep save_buffer;            /* buffer for previously read data */
    370    png_bytep current_buffer_ptr;     /* current location in current_buffer */
    371    png_bytep current_buffer;         /* buffer for recently used data */
    372    png_uint_32 push_length;          /* size of current input chunk */
    373    png_uint_32 skip_length;          /* bytes to skip in input data */
    374    png_size_t save_buffer_size;      /* amount of data now in save_buffer */
    375    png_size_t save_buffer_max;       /* total size of save_buffer */
    376    png_size_t buffer_size;           /* total amount of available input data */
    377    png_size_t current_buffer_size;   /* amount of data now in current_buffer */
    378    int process_mode;                 /* what push library is currently doing */
    379    int cur_palette;                  /* current push library palette index */
    380 
    381 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
    382 
    383 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
    384 /* For the Borland special 64K segment handler */
    385    png_bytepp offset_table_ptr;
    386    png_bytep offset_table;
    387    png_uint_16 offset_table_number;
    388    png_uint_16 offset_table_count;
    389    png_uint_16 offset_table_count_free;
    390 #endif
    391 
    392 #ifdef PNG_READ_QUANTIZE_SUPPORTED
    393    png_bytep palette_lookup; /* lookup table for quantizing */
    394    png_bytep quantize_index; /* index translation for palette files */
    395 #endif
    396 
    397 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
    398    png_byte heuristic_method;        /* heuristic for row filter selection */
    399    png_byte num_prev_filters;        /* number of weights for previous rows */
    400    png_bytep prev_filters;           /* filter type(s) of previous row(s) */
    401    png_uint_16p filter_weights;      /* weight(s) for previous line(s) */
    402    png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */
    403    png_uint_16p filter_costs;        /* relative filter calculation cost */
    404    png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */
    405 #endif
    406 
    407    /* Options */
    408 #ifdef PNG_SET_OPTION_SUPPORTED
    409    png_byte options;           /* On/off state (up to 4 options) */
    410 #endif
    411 
    412 #if PNG_LIBPNG_VER < 10700
    413 /* To do: remove this from libpng-1.7 */
    414 #ifdef PNG_TIME_RFC1123_SUPPORTED
    415    char time_buffer[29]; /* String to hold RFC 1123 time text */
    416 #endif
    417 #endif
    418 
    419 /* New members added in libpng-1.0.6 */
    420 
    421    png_uint_32 free_me;    /* flags items libpng is responsible for freeing */
    422 
    423 #ifdef PNG_USER_CHUNKS_SUPPORTED
    424    png_voidp user_chunk_ptr;
    425 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
    426    png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
    427 #endif
    428 #endif
    429 
    430 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
    431    int          unknown_default; /* As PNG_HANDLE_* */
    432    unsigned int num_chunk_list;  /* Number of entries in the list */
    433    png_bytep    chunk_list;      /* List of png_byte[5]; the textual chunk name
    434                                   * followed by a PNG_HANDLE_* byte */
    435 #endif
    436 
    437 /* New members added in libpng-1.0.3 */
    438 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
    439    png_byte rgb_to_gray_status;
    440    /* Added in libpng 1.5.5 to record setting of coefficients: */
    441    png_byte rgb_to_gray_coefficients_set;
    442    /* These were changed from png_byte in libpng-1.0.6 */
    443    png_uint_16 rgb_to_gray_red_coeff;
    444    png_uint_16 rgb_to_gray_green_coeff;
    445    /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */
    446 #endif
    447 
    448 /* New member added in libpng-1.0.4 (renamed in 1.0.9) */
    449 #if defined(PNG_MNG_FEATURES_SUPPORTED)
    450 /* Changed from png_byte to png_uint_32 at version 1.2.0 */
    451    png_uint_32 mng_features_permitted;
    452 #endif
    453 
    454 /* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
    455 #ifdef PNG_MNG_FEATURES_SUPPORTED
    456    png_byte filter_type;
    457 #endif
    458 
    459 /* New members added in libpng-1.2.0 */
    460 
    461 /* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
    462 #ifdef PNG_USER_MEM_SUPPORTED
    463    png_voidp mem_ptr;             /* user supplied struct for mem functions */
    464    png_malloc_ptr malloc_fn;      /* function for allocating memory */
    465    png_free_ptr free_fn;          /* function for freeing memory */
    466 #endif
    467 
    468 /* New member added in libpng-1.0.13 and 1.2.0 */
    469    png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */
    470 
    471 #ifdef PNG_READ_QUANTIZE_SUPPORTED
    472 /* The following three members were added at version 1.0.14 and 1.2.4 */
    473    png_bytep quantize_sort;          /* working sort array */
    474    png_bytep index_to_palette;       /* where the original index currently is
    475                                         in the palette */
    476    png_bytep palette_to_index;       /* which original index points to this
    477                                          palette color */
    478 #endif
    479 
    480 /* New members added in libpng-1.0.16 and 1.2.6 */
    481    png_byte compression_type;
    482 
    483 #ifdef PNG_USER_LIMITS_SUPPORTED
    484    png_uint_32 user_width_max;
    485    png_uint_32 user_height_max;
    486 
    487    /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
    488     * chunks that can be stored (0 means unlimited).
    489     */
    490    png_uint_32 user_chunk_cache_max;
    491 
    492    /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
    493     * can occupy when decompressed.  0 means unlimited.
    494     */
    495    png_alloc_size_t user_chunk_malloc_max;
    496 #endif
    497 
    498 /* New member added in libpng-1.0.25 and 1.2.17 */
    499 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
    500    /* Temporary storage for unknown chunk that the library doesn't recognize,
    501     * used while reading the chunk.
    502     */
    503    png_unknown_chunk unknown_chunk;
    504 #endif
    505 
    506 /* New member added in libpng-1.2.26 */
    507   png_size_t old_big_row_buf_size;
    508 
    509 #ifdef PNG_READ_SUPPORTED
    510 /* New member added in libpng-1.2.30 */
    511   png_bytep        read_buffer;      /* buffer for reading chunk data */
    512   png_alloc_size_t read_buffer_size; /* current size of the buffer */
    513 #endif
    514 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
    515   uInt             IDAT_read_size;   /* limit on read buffer size for IDAT */
    516 #endif
    517 
    518 #ifdef PNG_IO_STATE_SUPPORTED
    519 /* New member added in libpng-1.4.0 */
    520    png_uint_32 io_state;
    521 #endif
    522 
    523 /* New member added in libpng-1.5.6 */
    524    png_bytep big_prev_row;
    525 
    526 /* New member added in libpng-1.5.7 */
    527    void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
    528       png_bytep row, png_const_bytep prev_row);
    529 
    530 #ifdef PNG_READ_SUPPORTED
    531 #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
    532    png_colorspace   colorspace;
    533 #endif
    534 #endif
    535 
    536 #ifdef PNG_INDEX_SUPPORTED
    537    png_indexp index;
    538    png_uint_32 total_data_read;
    539 #endif
    540 
    541 };
    542 #endif /* PNGSTRUCT_H */
    543