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/* pngstruct.h - header file for PNG reference library
* Last changed in libpng 1.6.18 [July 23, 2015]
* Copyright (c) 1998-2015 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.)
* 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.
/* 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
#include "zlib.h"
#ifdef const
/* zlib.h sometimes #defines const to nothing, undo this. */
# undef const
/* 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)
# define PNGZ_MSG_CAST(s) (s)
# define PNGZ_INPUT_CAST(b) (b)
/* 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)
/* 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;
(offsetof(png_compression_buffer, output) + (pp)->zbuffer_size)
/* 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.
/* 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 */
/* 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
png_fixed_point gamma; /* File gamma */
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 */
/* 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_MATCHES_sRGB 0x0080 /* exact match on profile */
#define PNG_COLORSPACE_CANCEL(flags) (0xffff ^ (flags))
#endif /* COLORSPACE || GAMMA */
/* png_line_index_struct records an index point, where we impose an index point
* to be located at the beginning of a line for simplifying the implementation.
typedef struct png_line_index_struct
// state of the lz decoder
z_streamp z_state;
// the IDAT header position of the chunk, which the index point is in
png_uint_32 stream_idat_position;
// we intend to record the offset of the index point in the chunk,
// but we record the number of remaining bytes in the chunk after the
// index point. That's because PNG processes a chunk this way.
png_uint_32 bytes_left_in_idat;
// decompressed data of the previous row
png_bytep prev_row;
} png_line_index;
typedef png_line_index FAR * png_line_indexp;
typedef struct png_index_struct
// A temporary variable used when we build the index. The variable records
// the IDAT header position of the last chunk read in so far.
png_uint_32 stream_idat_position;
// line index information about each passes
// the number of index points in each pass
png_uint_32 size[7];
// the line span of two index points of each pass
png_uint_32 step[7];
// the index points of each pass
png_line_indexp *pass_line_index[7];
} png_index;
typedef png_index FAR * png_indexp;
struct png_struct_def
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 */
png_error_ptr error_fn; /* function for printing errors and aborting */
png_error_ptr warning_fn; /* function for printing warnings */
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_seek_ptr seek_data_fn; /* function for seeking input data */
png_voidp io_ptr; /* ptr to application struct for I/O functions */
png_user_transform_ptr read_user_transform_fn; /* user read transform */
png_user_transform_ptr write_user_transform_fn; /* user write transform */
/* These were added in libpng-1.0.2 */
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 */
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 */
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 */
/* Added at libpng 1.5.4 */
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 */
/* End of material added at libpng 1.5.4 */
/* Added at libpng 1.6.0 */
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;
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.
* While reading this is a pointer into
* big_prev_row; while writing it is separately
* allocated if needed.
png_bytep row_buf; /* buffer to save current (unfiltered) row.
* While reading, this is a pointer into
* big_row_buf; while writing it is separately
* allocated.
png_bytep try_row; /* buffer to save trial row when filtering */
png_bytep tst_row; /* buffer to save best trial row when filtering */
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 */
int num_palette_max; /* maximum palette index found in IDAT */
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 */
png_byte usr_channels; /* channels at start of write: write only */
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 PNG_ZLIB_VERNUM >= 0x1240
png_byte zstream_start; /* at start of an input zlib stream */
#endif /* Zlib >= 1.2.4 */
png_uint_16 filler; /* filler bytes for pixel expansion */
png_byte background_gamma_type;
png_fixed_point background_gamma;
png_color_16 background; /* background color in screen gamma space */
png_color_16 background_1; /* background normalized to gamma 1.0 */
#endif /* bKGD */
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 */
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 */
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 */
png_color_8 sig_bit; /* significant bits in each available channel */
png_color_8 shift; /* shift for significant bit tranformation */
png_bytep trans_alpha; /* alpha values for paletted files */
png_color_16 trans_color; /* transparent color for non-paletted files */
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 */
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 */
#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;
png_bytep palette_lookup; /* lookup table for quantizing */
png_bytep quantize_index; /* index translation for palette files */
/* Options */
png_byte options; /* On/off state (up to 4 options) */
#if PNG_LIBPNG_VER < 10700
/* To do: remove this from libpng-1.7 */
char time_buffer[29]; /* String to hold RFC 1123 time text */
/* New members added in libpng-1.0.6 */
png_uint_32 free_me; /* flags items libpng is responsible for freeing */
png_voidp user_chunk_ptr;
png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
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 */
/* New members added in libpng-1.0.3 */
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; */
/* New member added in libpng-1.0.4 (renamed in 1.0.9) */
/* Changed from png_byte to png_uint_32 at version 1.2.0 */
png_uint_32 mng_features_permitted;
/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
png_byte filter_type;
/* 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 */
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 */
/* New member added in libpng-1.0.13 and 1.2.0 */
png_bytep big_row_buf; /* buffer to save current (unfiltered) row */
/* 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 */
/* New members added in libpng-1.0.16 and 1.2.6 */
png_byte compression_type;
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;
/* New member added in libpng-1.0.25 and 1.2.17 */
/* Temporary storage for unknown chunk that the library doesn't recognize,
* used while reading the chunk.
png_unknown_chunk unknown_chunk;
/* New member added in libpng-1.2.26 */
png_size_t old_big_row_buf_size;
/* 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 */
uInt IDAT_read_size; /* limit on read buffer size for IDAT */
/* New member added in libpng-1.4.0 */
png_uint_32 io_state;
/* 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);
png_colorspace colorspace;
png_indexp index;
png_uint_32 total_data_read;
#endif /* PNGSTRUCT_H */