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

 *

 * Copyright (c) 2018-2022 Cosmin Truta

 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson

 * Copyright (c) 1996-1997 Andreas Dilger

 * 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.

 */

#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

 * maximum for size_t.  The value can be overridden 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 */

   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.

                               */

#ifdef PNG_WRITE_FILTER_SUPPORTED

   png_bytep try_row;    /* buffer to save trial row when filtering */

   png_bytep tst_row;    /* buffer to save best trial row when filtering */

#endif

   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_ in png.h ) */

   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 ZLIB_VERNUM >= 0x1240

   png_byte zstream_start;    /* at start of an input zlib stream */

#endif /* Zlib >= 1.2.4 */

#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 /* bKGD */

#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 transformation */

#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 */

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

   size_t save_buffer_max;           /* total size of save_buffer */

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

   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 /* PROGRESSIVE_READ */

#ifdef PNG_READ_QUANTIZE_SUPPORTED

   png_bytep palette_lookup; /* lookup table for quantizing */

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

#endif

/* Options */

#ifdef PNG_SET_OPTION_SUPPORTED

   png_uint_32 options;           /* On/off state (up to 16 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-1.6.36 */

#if defined(PNG_READ_EXPAND_SUPPORTED) && \

    defined(PNG_ARM_NEON_IMPLEMENTATION)

   png_bytep riffled_palette; /* buffer for accelerated palette expansion */

#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

/* 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 */

   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 */