/* 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. */ /* 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; /* Chunk index values as an enum, PNG_INDEX_unknown is also a count of the * number of chunks. */ #define PNG_CHUNK(cHNK, i) PNG_INDEX_ ## cHNK = (i), typedef enum { PNG_KNOWN_CHUNKS PNG_INDEX_unknown } png_index; #undef PNG_CHUNK /* Chunk flag values. These are (png_uint_32 values) with exactly one bit set * and can be combined into a flag set with bitwise 'or'. * * TODO: C23: convert these macros to C23 inlines (which are static). */ #define png_chunk_flag_from_index(i) (0x80000000U >> (31 - (i))) /* The flag coresponding to the given png_index enum value. This is defined * for png_unknown as well (until it reaches the value 32) but this should * not be relied on. */ #define png_file_has_chunk(png_ptr, i)\ (((png_ptr)->chunks & png_chunk_flag_from_index(i)) != 0) /* The chunk has been recorded in png_struct */ #define png_file_add_chunk(pnt_ptr, i)\ ((void)((png_ptr)->chunks |= png_chunk_flag_from_index(i))) /* Record the chunk in the png_struct */ 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 chunks; /* PNG_CF_ for every chunk read or (NYI) written */ # define png_has_chunk(png_ptr, cHNK)\ png_file_has_chunk(png_ptr, PNG_INDEX_ ## cHNK) /* Convenience accessor - use this to check for a known chunk by name */ 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_RGB_TO_GRAY_SUPPORTED png_xy chromaticities; /* From mDVC, cICP, [iCCP], sRGB or cHRM */ #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_fixed_point file_gamma; /* file gamma value (encoding exponent) */ png_fixed_point chunk_gamma; /* from cICP, iCCP, sRGB or gAMA */ png_fixed_point default_gamma;/* from png_set_alpha_mode */ 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 /* READ_GAMMA */ #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 /* TIME_RFC1123 */ #endif /* LIBPNG_VER < 10700 */ /* 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 /* READ_USER_CHUNKS */ #endif /* USER_CHUNKS */ #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); }; #endif /* PNGSTRUCT_H */