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 /* pngstruct.h - header file for PNG reference library

  *

  * Copyright (c) 1998-2013 Glenn Randers-Pehrson

  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)

  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)

  *

  * Last changed in libpng 1.6.1 [March 28, 2013]

  *

  * This code is released under the libpng license.

  * For conditions of distribution and use, see the disclaimer

  * and license in png.h

  */

 /* The structure that holds the information to read and write PNG files.

  * The only people who need to care about what is inside of this are the

  * people who will be modifying the library for their own special needs.

  * It should NOT be accessed directly by an application.

  */

 #ifndef PNGSTRUCT_H

 #define PNGSTRUCT_H

 /* zlib.h defines the structure z_stream, an instance of which is included

  * in this structure and is required for decompressing the LZ compressed

  * data in PNG files.

  */

 #ifndef ZLIB_CONST

    /* We must ensure that zlib uses 'const' in declarations. */

 #  define ZLIB_CONST

 #endif

 #include "zlib.h"

 #ifdef const

    /* zlib.h sometimes #defines const to nothing, undo this. */

 #  undef const

 #endif

 /* zlib.h has mediocre z_const use before 1.2.6, this stuff is for compatibility

  * with older builds.

  */

 #if ZLIB_VERNUM < 0x1260

 #  define PNGZ_MSG_CAST(s) png_constcast(char*,s)

 #  define PNGZ_INPUT_CAST(b) png_constcast(png_bytep,b)

 #else

 #  define PNGZ_MSG_CAST(s) (s)

 #  define PNGZ_INPUT_CAST(b) (b)

 #endif

 /* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib

  * can handle at once.  This type need be no larger than 16 bits (so maximum of

  * 65535), this define allows us to discover how big it is, but limited by the

  * maximuum for png_size_t.  The value can be overriden in a library build

  * (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably

  * lower value (e.g. 255 works).  A lower value may help memory usage (slightly)

  * and may even improve performance on some systems (and degrade it on others.)

  */

 #ifndef ZLIB_IO_MAX

 #  define ZLIB_IO_MAX ((uInt)-1)

 #endif

 #ifdef PNG_WRITE_SUPPORTED

 /* The type of a compression buffer list used by the write code. */

 typedef struct png_compression_buffer

 {

    struct png_compression_buffer *next;

    png_byte                       output[1]; /* actually zbuf_size */

 } png_compression_buffer, *png_compression_bufferp;

 #define PNG_COMPRESSION_BUFFER_SIZE(pp)\

    (offsetof(png_compression_buffer, output) + (pp)->zbuffer_size)

 #endif

 /* Colorspace support; structures used in png_struct, png_info and in internal

  * functions to hold and communicate information about the color space.

  *

  * PNG_COLORSPACE_SUPPORTED is only required if the application will perform

  * colorspace corrections, otherwise all the colorspace information can be

  * skipped and the size of libpng can be reduced (significantly) by compiling

  * out the colorspace support.

  */

 #ifdef PNG_COLORSPACE_SUPPORTED

 /* The chromaticities of the red, green and blue colorants and the chromaticity

  * of the corresponding white point (i.e. of rgb(1.0,1.0,1.0)).

  */

 typedef struct png_xy

 {

    png_fixed_point redx, redy;

    png_fixed_point greenx, greeny;

    png_fixed_point bluex, bluey;

    png_fixed_point whitex, whitey;

 } png_xy;

 /* The same data as above but encoded as CIE XYZ values.  When this data comes

  * from chromaticities the sum of the Y values is assumed to be 1.0

  */

 typedef struct png_XYZ

 {

    png_fixed_point red_X, red_Y, red_Z;

    png_fixed_point green_X, green_Y, green_Z;

    png_fixed_point blue_X, blue_Y, blue_Z;

 } png_XYZ;

 #endif /* COLORSPACE */

 #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)

 /* A colorspace is all the above plus, potentially, profile information,

  * however at present libpng does not use the profile internally so it is only

  * stored in the png_info struct (if iCCP is supported.)  The rendering intent

  * is retained here and is checked.

  *

  * The file gamma encoding information is also stored here and gamma correction

  * is done by libpng, whereas color correction must currently be done by the

  * application.

  */

 typedef struct png_colorspace

 {

 #ifdef PNG_GAMMA_SUPPORTED

    png_fixed_point gamma;        /* File gamma */

 #endif

 #ifdef PNG_COLORSPACE_SUPPORTED

    png_xy      end_points_xy;    /* End points as chromaticities */

    png_XYZ     end_points_XYZ;   /* End points as CIE XYZ colorant values */

    png_uint_16 rendering_intent; /* Rendering intent of a profile */

 #endif

    /* Flags are always defined to simplify the code. */

    png_uint_16 flags;            /* As defined below */

 } png_colorspace, * PNG_RESTRICT png_colorspacerp;

 typedef const png_colorspace * PNG_RESTRICT png_const_colorspacerp;

 /* General flags for the 'flags' field */

 #define PNG_COLORSPACE_HAVE_GAMMA           0x0001

 #define PNG_COLORSPACE_HAVE_ENDPOINTS       0x0002

 #define PNG_COLORSPACE_HAVE_INTENT          0x0004

 #define PNG_COLORSPACE_FROM_gAMA            0x0008

 #define PNG_COLORSPACE_FROM_cHRM            0x0010

 #define PNG_COLORSPACE_FROM_sRGB            0x0020

 #define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0040

 #define PNG_COLORSPACE_MATCHES_sRGB         0x0080 /* exact match on profile */

 #define PNG_COLORSPACE_INVALID              0x8000

 #define PNG_COLORSPACE_CANCEL(flags)        (0xffff ^ (flags))

 #endif /* COLORSPACE || GAMMA */

 struct png_struct_def

 {

 #ifdef PNG_SETJMP_SUPPORTED

    jmp_buf jmp_buf_local;     /* New name in 1.6.0 for jmp_buf in png_struct */

    png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */

    jmp_buf *jmp_buf_ptr;      /* passed to longjmp_fn */

    size_t jmp_buf_size;       /* size of the above, if allocated */

 #endif

    png_error_ptr error_fn;    /* function for printing errors and aborting */

 #ifdef PNG_WARNINGS_SUPPORTED

    png_error_ptr warning_fn;  /* function for printing warnings */

 #endif

    png_voidp error_ptr;       /* user supplied struct for error functions */

    png_rw_ptr write_data_fn;  /* function for writing output data */

    png_rw_ptr read_data_fn;   /* function for reading input data */

    png_voidp io_ptr;          /* ptr to application struct for I/O functions */

 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED

    png_user_transform_ptr read_user_transform_fn; /* user read transform */

 #endif

 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED

    png_user_transform_ptr write_user_transform_fn; /* user write transform */

 #endif

 /* These were added in libpng-1.0.2 */

 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED

 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \

     defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)

    png_voidp user_transform_ptr; /* user supplied struct for user transform */

    png_byte user_transform_depth;    /* bit depth of user transformed pixels */

    png_byte user_transform_channels; /* channels in user transformed pixels */

 #endif

 #endif

    png_uint_32 mode;          /* tells us where we are in the PNG file */

    png_uint_32 flags;         /* flags indicating various things to libpng */

    png_uint_32 transformations; /* which transformations to perform */

    png_uint_32 zowner;        /* ID (chunk type) of zstream owner, 0 if none */

    z_stream    zstream;       /* decompression structure */

 #ifdef PNG_WRITE_SUPPORTED

    png_compression_bufferp zbuffer_list; /* Created on demand during write */

    uInt                    zbuffer_size; /* size of the actual buffer */

    int zlib_level;            /* holds zlib compression level */

    int zlib_method;           /* holds zlib compression method */

    int zlib_window_bits;      /* holds zlib compression window bits */

    int zlib_mem_level;        /* holds zlib compression memory level */

    int zlib_strategy;         /* holds zlib compression strategy */

 #endif

 /* Added at libpng 1.5.4 */

 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED

    int zlib_text_level;            /* holds zlib compression level */

    int zlib_text_method;           /* holds zlib compression method */

    int zlib_text_window_bits;      /* holds zlib compression window bits */

    int zlib_text_mem_level;        /* holds zlib compression memory level */

    int zlib_text_strategy;         /* holds zlib compression strategy */

 #endif

 /* End of material added at libpng 1.5.4 */

 /* Added at libpng 1.6.0 */

 #ifdef PNG_WRITE_SUPPORTED

    int zlib_set_level;        /* Actual values set into the zstream on write */

    int zlib_set_method;

    int zlib_set_window_bits;

    int zlib_set_mem_level;

    int zlib_set_strategy;

 #endif

    png_uint_32 width;         /* width of image in pixels */

    png_uint_32 height;        /* height of image in pixels */

    png_uint_32 num_rows;      /* number of rows in current pass */

    png_uint_32 usr_width;     /* width of row at start of write */

    png_size_t rowbytes;       /* size of row in bytes */

    png_uint_32 iwidth;        /* width of current interlaced row in pixels */

    png_uint_32 row_number;    /* current row in interlace pass */

    png_uint_32 chunk_name;    /* PNG_CHUNK() id of current chunk */

    png_bytep prev_row;        /* buffer to save previous (unfiltered) row.

                                * This is a pointer into big_prev_row

                                */

    png_bytep row_buf;         /* buffer to save current (unfiltered) row.

                                * This is a pointer into big_row_buf

                                */

 #ifdef PNG_WRITE_SUPPORTED

    png_bytep sub_row;         /* buffer to save "sub" row when filtering */

    png_bytep up_row;          /* buffer to save "up" row when filtering */

    png_bytep avg_row;         /* buffer to save "avg" row when filtering */

    png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */

 #endif

    png_size_t info_rowbytes;  /* Added in 1.5.4: cache of updated row bytes */

    png_uint_32 idat_size;     /* current IDAT size for read */

    png_uint_32 crc;           /* current chunk CRC value */

    png_colorp palette;        /* palette from the input file */

    png_uint_16 num_palette;   /* number of color entries in palette */

 /* Added at libpng-1.5.10 */

 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED

    int num_palette_max;       /* maximum palette index found in IDAT */

 #endif

    png_uint_16 num_trans;     /* number of transparency values */

    png_byte compression;      /* file compression type (always 0) */

    png_byte filter;           /* file filter type (always 0) */

    png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */

    png_byte pass;             /* current interlace pass (0 - 6) */

    png_byte do_filter;        /* row filter flags (see PNG_FILTER_ below ) */

    png_byte color_type;       /* color type of file */

    png_byte bit_depth;        /* bit depth of file */

    png_byte usr_bit_depth;    /* bit depth of users row: write only */

    png_byte pixel_depth;      /* number of bits per pixel */

    png_byte channels;         /* number of channels in file */

 #ifdef PNG_WRITE_SUPPORTED

    png_byte usr_channels;     /* channels at start of write: write only */

 #endif

    png_byte sig_bytes;        /* magic bytes read/written from start of file */

    png_byte maximum_pixel_depth;

                               /* pixel depth used for the row buffers */

    png_byte transformed_pixel_depth;

                               /* pixel depth after read/write transforms */

 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)

    png_uint_16 filler;           /* filler bytes for pixel expansion */

 #endif

 #if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\

    defined(PNG_READ_ALPHA_MODE_SUPPORTED)

    png_byte background_gamma_type;

    png_fixed_point background_gamma;

    png_color_16 background;   /* background color in screen gamma space */

 #ifdef PNG_READ_GAMMA_SUPPORTED

    png_color_16 background_1; /* background normalized to gamma 1.0 */

 #endif

 #endif /* PNG_bKGD_SUPPORTED */

 #ifdef PNG_WRITE_FLUSH_SUPPORTED

    png_flush_ptr output_flush_fn; /* Function for flushing output */

    png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */

    png_uint_32 flush_rows;    /* number of rows written since last flush */

 #endif

 #ifdef PNG_READ_GAMMA_SUPPORTED

    int gamma_shift;      /* number of "insignificant" bits in 16-bit gamma */

    png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */

    png_bytep gamma_table;     /* gamma table for 8-bit depth files */

    png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */

 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \

    defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \

    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)

    png_bytep gamma_from_1;    /* converts from 1.0 to screen */

    png_bytep gamma_to_1;      /* converts from file to 1.0 */

    png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */

    png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */

 #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */

 #endif

 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)

    png_color_8 sig_bit;       /* significant bits in each available channel */

 #endif

 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)

    png_color_8 shift;         /* shift for significant bit tranformation */

 #endif

 #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \

  || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)

    png_bytep trans_alpha;           /* alpha values for paletted files */

    png_color_16 trans_color;  /* transparent color for non-paletted files */

 #endif

    png_read_status_ptr read_row_fn;   /* called after each row is decoded */

    png_write_status_ptr write_row_fn; /* called after each row is encoded */

 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED

    png_progressive_info_ptr info_fn; /* called after header data fully read */

    png_progressive_row_ptr row_fn;   /* called after a prog. row is decoded */

    png_progressive_end_ptr end_fn;   /* called after image is complete */

    png_bytep save_buffer_ptr;        /* current location in save_buffer */

    png_bytep save_buffer;            /* buffer for previously read data */

    png_bytep current_buffer_ptr;     /* current location in current_buffer */

    png_bytep current_buffer;         /* buffer for recently used data */

    png_uint_32 push_length;          /* size of current input chunk */

    png_uint_32 skip_length;          /* bytes to skip in input data */

    png_size_t save_buffer_size;      /* amount of data now in save_buffer */

    png_size_t save_buffer_max;       /* total size of save_buffer */

    png_size_t buffer_size;           /* total amount of available input data */

    png_size_t current_buffer_size;   /* amount of data now in current_buffer */

    int process_mode;                 /* what push library is currently doing */

    int cur_palette;                  /* current push library palette index */

 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */

 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)

 /* For the Borland special 64K segment handler */

    png_bytepp offset_table_ptr;

    png_bytep offset_table;

    png_uint_16 offset_table_number;

    png_uint_16 offset_table_count;

    png_uint_16 offset_table_count_free;

 #endif

 #ifdef PNG_READ_QUANTIZE_SUPPORTED

    png_bytep palette_lookup; /* lookup table for quantizing */

    png_bytep quantize_index; /* index translation for palette files */

 #endif

 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED

    png_byte heuristic_method;        /* heuristic for row filter selection */

    png_byte num_prev_filters;        /* number of weights for previous rows */

    png_bytep prev_filters;           /* filter type(s) of previous row(s) */

    png_uint_16p filter_weights;      /* weight(s) for previous line(s) */

    png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */

    png_uint_16p filter_costs;        /* relative filter calculation cost */

    png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */

 #endif

    /* Options */

 #ifdef PNG_SET_OPTION_SUPPORTED

    png_byte options;           /* On/off state (up to 4 options) */

 #endif

 #if PNG_LIBPNG_VER < 10700

 /* To do: remove this from libpng-1.7 */

 #ifdef PNG_TIME_RFC1123_SUPPORTED

    char time_buffer[29]; /* String to hold RFC 1123 time text */

 #endif

 #endif

 /* New members added in libpng-1.0.6 */

    png_uint_32 free_me;    /* flags items libpng is responsible for freeing */

 #ifdef PNG_USER_CHUNKS_SUPPORTED

    png_voidp user_chunk_ptr;

 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED

    png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */

 #endif

 #endif

 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED

    int          unknown_default; /* As PNG_HANDLE_* */

    unsigned int num_chunk_list;  /* Number of entries in the list */

    png_bytep    chunk_list;      /* List of png_byte[5]; the textual chunk name

                                   * followed by a PNG_HANDLE_* byte */

 #endif

 /* New members added in libpng-1.0.3 */

 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED

    png_byte rgb_to_gray_status;

    /* Added in libpng 1.5.5 to record setting of coefficients: */

    png_byte rgb_to_gray_coefficients_set;

    /* These were changed from png_byte in libpng-1.0.6 */

    png_uint_16 rgb_to_gray_red_coeff;

    png_uint_16 rgb_to_gray_green_coeff;

    /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */

 #endif

 /* New member added in libpng-1.0.4 (renamed in 1.0.9) */

 #if defined(PNG_MNG_FEATURES_SUPPORTED)

 /* Changed from png_byte to png_uint_32 at version 1.2.0 */

    png_uint_32 mng_features_permitted;

 #endif

 /* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */

 #ifdef PNG_MNG_FEATURES_SUPPORTED

    png_byte filter_type;

 #endif

 #ifdef PNG_APNG_SUPPORTED

    png_uint_32 apng_flags;

    png_uint_32 next_seq_num;         /* next fcTL/fdAT chunk sequence number */

    png_uint_32 first_frame_width;

    png_uint_32 first_frame_height;

 #ifdef PNG_READ_APNG_SUPPORTED

    png_uint_32 num_frames_read;      /* incremented after all image data of */

                                      /* a frame is read */

 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED

    png_progressive_frame_ptr frame_info_fn; /* frame info read callback */

    png_progressive_frame_ptr frame_end_fn;  /* frame data read callback */

 #endif

 #endif

 #ifdef PNG_WRITE_APNG_SUPPORTED

    png_uint_32 num_frames_to_write;

    png_uint_32 num_frames_written;

 #endif

 #endif /* PNG_APNG_SUPPORTED */

 /* New members added in libpng-1.2.0 */

 /* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */

 #ifdef PNG_USER_MEM_SUPPORTED

    png_voidp mem_ptr;             /* user supplied struct for mem functions */

    png_malloc_ptr malloc_fn;      /* function for allocating memory */

    png_free_ptr free_fn;          /* function for freeing memory */

 #endif

 /* New member added in libpng-1.0.13 and 1.2.0 */

    png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */

 #ifdef PNG_READ_QUANTIZE_SUPPORTED

 /* The following three members were added at version 1.0.14 and 1.2.4 */

    png_bytep quantize_sort;          /* working sort array */

    png_bytep index_to_palette;       /* where the original index currently is

                                         in the palette */

    png_bytep palette_to_index;       /* which original index points to this

                                          palette color */

 #endif

 /* New members added in libpng-1.0.16 and 1.2.6 */

    png_byte compression_type;

 #ifdef PNG_USER_LIMITS_SUPPORTED

    png_uint_32 user_width_max;

    png_uint_32 user_height_max;

    /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown

     * chunks that can be stored (0 means unlimited).

     */

    png_uint_32 user_chunk_cache_max;

    /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk

     * can occupy when decompressed.  0 means unlimited.

     */

    png_alloc_size_t user_chunk_malloc_max;

 #endif

 /* New member added in libpng-1.0.25 and 1.2.17 */

 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED

    /* Temporary storage for unknown chunk that the library doesn't recognize,

     * used while reading the chunk.

     */

    png_unknown_chunk unknown_chunk;

 #endif

 /* New member added in libpng-1.2.26 */

   png_size_t old_big_row_buf_size;

 #ifdef PNG_READ_SUPPORTED

 /* New member added in libpng-1.2.30 */

   png_bytep        read_buffer;      /* buffer for reading chunk data */

   png_alloc_size_t read_buffer_size; /* current size of the buffer */

 #endif

 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED

   uInt             IDAT_read_size;   /* limit on read buffer size for IDAT */

 #endif

 #ifdef PNG_IO_STATE_SUPPORTED

 /* New member added in libpng-1.4.0 */

    png_uint_32 io_state;

 #endif

 /* New member added in libpng-1.5.6 */

    png_bytep big_prev_row;

 /* New member added in libpng-1.5.7 */

    void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,

       png_bytep row, png_const_bytep prev_row);

 #ifdef PNG_READ_SUPPORTED

 #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)

    png_colorspace   colorspace;

 #endif

 #endif

 };

 #endif /* PNGSTRUCT_H */