| |
| /* pngstruct.h - header file for PNG reference library |
| * |
| * Last changed in libpng 1.7.0 [(PENDING RELEASE)] |
| * Copyright (c) 1998-2002,2004,2006-2016 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. |
| */ |
| |
| #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 /* !ZLIB_CONST */ |
| |
| #include PNG_ZLIB_HEADER |
| |
| #ifdef const |
| /* zlib.h sometimes #defines const to nothing, undo this. */ |
| # undef const |
| #endif /* 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) |
| #else /* ZLIB_VERNUM >= 0x1260 */ |
| # define PNGZ_MSG_CAST(s) (s) |
| # define PNGZ_INPUT_CAST(b) (b) |
| #endif /* ZLIB_VERNUM >= 0x1260 */ |
| |
| /* 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 |
| # ifdef __COVERITY__ |
| # define ZLIB_IO_MAX ((uInt)255U) /* else COVERITY whines */ |
| # else /* !COVERITY */ |
| # define ZLIB_IO_MAX ((uInt)-1) |
| # endif /* !COVERITY */ |
| #endif /* !ZLIB_IO_MAX */ |
| |
| #ifdef PNG_WRITE_SUPPORTED |
| /* The write compression control (allocated on demand). |
| * TODO: use this for the read state too. |
| */ |
| typedef struct png_zlib_state *png_zlib_statep; |
| #endif /* WRITE */ |
| |
| /* 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 /* GAMMA */ |
| |
| #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 /* COLORSPACE */ |
| |
| /* 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 0x0001U |
| #define PNG_COLORSPACE_HAVE_ENDPOINTS 0x0002U |
| #define PNG_COLORSPACE_HAVE_INTENT 0x0004U |
| #define PNG_COLORSPACE_FROM_gAMA 0x0008U |
| #define PNG_COLORSPACE_FROM_cHRM 0x0010U |
| #define PNG_COLORSPACE_FROM_sRGB 0x0020U |
| #define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0040U |
| #define PNG_COLORSPACE_MATCHES_sRGB 0x0080U /* exact match on profile */ |
| #define PNG_COLORSPACE_RGB_TO_GRAY_SET 0x0100U /* user specified coeffs */ |
| #define PNG_COLORSPACE_INVALID 0x8000U |
| #define PNG_COLORSPACE_CANCEL(flags) (0xffffU - (flags)) |
| #endif /* COLORSPACE || GAMMA */ |
| |
| #ifdef PNG_TRANSFORM_MECH_SUPPORTED |
| /***************************** READ and WRITE TRANSFORMS *********************** |
| * These structures are used in pngrtran.c, pngwtran.c and pngtrans.c to hold |
| * information about transforms in progress. This mechanism was introduced in |
| * libpng 1.7.0 to ensure reliable transform code and to fix multiple bugs in |
| * the pre-1.7 transform handling. |
| * |
| * Prior to 1.7.0 the internal transform routines took a png_row_infop, like the |
| * user transform function, but without the png_ptr because it was never used. |
| * In 1.7.0 a separate internal structure is used in place of this to allow both |
| * future development to change the structure. |
| * |
| * The values in this structure will normally be changed by transformation |
| * implementations. |
| ***************************** READ and WRITE TRANSFORMS **********************/ |
| typedef struct |
| { |
| png_structp png_ptr; /* png_struct for error handling and some |
| * transform parameters. May be aliased. |
| */ |
| png_const_voidp sp; /* Source; the input row. */ |
| png_voidp dp; /* Output buffer for the transformed row, |
| * this may be the same as sp. |
| */ |
| /* If the row is changed the tranform routine must write the result to |
| * dp[] and set sp to dp, otherwise it must not write to dp and must leave |
| * sp unchanged. dp[] and sp[] are both 'malloc' aligned; i.e. they have |
| * the system alignment, so the data can be read as any valid ANSI-C |
| * type. |
| */ |
| png_uint_32 width; /* width of row */ |
| # ifdef PNG_READ_GAMMA_SUPPORTED |
| png_fixed_point gamma; /* Current gamma of the row data */ |
| /* When a row is being transformed this contains the current gamma of the |
| * data if known. During initialization the value is used to accumulate |
| * information for png_struct::row_gamma in the first step, |
| * PNG_TC_INIT_FORMAT, then used to insert the correct gamma transforms |
| * during PNG_TC_INIT_FINAL. The field is only used on read; write |
| * transforms do not modify the gamma of the data. |
| */ |
| # endif /* READ_GAMMA */ |
| unsigned int format; /* As pngstruct::row_format below */ |
| unsigned int range; /* Count of range transforms */ |
| # define PNG_TC_CHANNELS(tc) PNG_FORMAT_CHANNELS((tc).format) |
| unsigned int bit_depth; /* bit depth of row */ |
| png_byte sBIT_R; |
| png_byte sBIT_G; |
| png_byte sBIT_B; |
| png_byte sBIT_A; /* Signnificant bits in the row channels. */ |
| /* The above four values are initially set to the number of bits significant |
| * in the input PNG data, R/G/B are set to the same (gray) value for |
| * grayscale input. All values are set to the bit depth if there is no sBIT |
| * chunk, if there is no alpha channel sBIT_A is set to the bit depth. |
| * |
| * When any potentially spurious bits have been cleared PNG_INFO_sBIT will be |
| * set in invalid_info. From this point on the above values record the |
| * approximate number of bits of accuracy in the channels and the lower bits |
| * should be preserved; they potentially contain useful information. |
| */ |
| # define PNG_TC_PIXEL_DEPTH(tc) (PNG_TC_CHANNELS(tc) * (tc).bit_depth) |
| # define PNG_TC_ROWBYTES(tc) PNG_ROWBYTES(PNG_TC_PIXEL_DEPTH(tc), (tc).width) |
| unsigned int invalid_info; /* PNG_INFO_* for invalidated chunks */ |
| unsigned int cost; /* Cache cost */ |
| # define PNG_CACHE_COST_LIMIT 0x100U |
| /* This is a runtime structure, so size doesn't matter much, and it helps |
| * code reliability to use real member names here. Feel free to experiment |
| * with integer values rather than bitfields. |
| */ |
| unsigned int init :2; /* 0 for processing, non zero for init: */ |
| # define PNG_TC_INIT_FORMAT 0x01U /* Initialization step 1: just set 'format', |
| * 'bit_depth' and 'gamma' to the output |
| * values iff the transform corresponds to |
| * a user requested change to those values. |
| */ |
| # define PNG_TC_INIT_FINAL 0x03U /* Initialization step 2; set the 'format' |
| * 'bit_depth' and 'gamma' to the values the |
| * transform will actually produce (which |
| * need not be the same as the above). |
| */ |
| /* During initialization 'init' must be set and sp and dp may be NULL. If |
| * neither flag is set sp and dp must be non-NULL. |
| * |
| * When the transform runs it must update 'format', 'bit_depth' and 'gamma' |
| * to the values previously reported during PNG_TC_INIT_FINAL; not doing so |
| * may result in an affirm from a later transform. |
| */ |
| unsigned int caching :1; /* The color values are being used to |
| * generate a cache of the transforms. |
| */ |
| unsigned int palette :1; /* The values come from a PNG palette and |
| * the palette will not be expanded. The |
| * CACHE flag must be set too. A |
| * transform which causes the palette to |
| * be expanded must clear this flag. |
| */ |
| #if 0 /* NYI */ |
| unsigned int interchannel:1; /* Set by a transform that combines two or |
| * more channels together; for example |
| * alpha composition or RGB to gray. |
| */ |
| #endif /* NYI */ |
| unsigned int channel_add :1; /* A channel (alpha/filler) was added */ |
| unsigned int strip_alpha :1; /* Set if the alpha channel will be |
| * stripped on read, this also prevents |
| * the tRNS chunk being expanded. Only |
| * some transforms check this, depending |
| * on the handling order and checks in |
| * pre-1.7 versions. |
| */ |
| unsigned int expand_tRNS :1; /* Set if the tRNS chunk should be |
| * expanded (ignored if read_strip_alpha |
| * is set). If this is *not* set |
| * transforms which do not use alpha/tRNS |
| * but would invalidate it (such as |
| * simple gamma correction) will simply |
| * mark the tRNS info as invalid. |
| */ |
| unsigned int transparent_alpha :1; /* Indicates that the alpha channel |
| * consists entirely of opaque (1.0 alpha) |
| * or completely transparent (0.0 alpha) |
| * pixels. Set when tRNS is expanded to |
| * alpha. |
| */ |
| unsigned int optimized_alpha :1; /* Meaningful only when bit_depth is |
| * 16 and gamma is 1 or unknown (0). |
| * Indicates that pixels which are opaque |
| * (alpha 1.0) have not been expanded to |
| * 16-bit linear; instead these pixels |
| * are encoded in the final format in |
| * png_struct::row_bit_depth and |
| * png_struct::row_gamma. This will |
| * invariably match the file format. |
| */ |
| } png_transform_control, *png_transform_controlp; |
| |
| typedef const png_transform_control *png_const_transform_controlp; |
| typedef const png_row_info *png_const_row_infop; |
| |
| typedef struct png_transform *png_transformp; /* Forward declaration */ |
| typedef void (*png_transform_free_fn)(/* Function to free a transform */ |
| png_const_structrp png_ptr, |
| png_transformp transform); /* pointer to this transform */ |
| /* This function need not exist in a transform, it must free all the data |
| * allocated within the transform but not the transform itself. It is called |
| * from png_transform_free. |
| */ |
| typedef void (*png_transform_fn)(/* Function to implement a transform */ |
| png_transformp *transform, /* pointer to this transform */ |
| png_transform_controlp control); /* row information */ |
| /* The transform function has two modes of operation: |
| * |
| * 1) Initialization. The list of transforms is processed from the start to |
| * the end and each function is called with one of hte PNG_TC_INIT_ flags |
| * set in control->flags, control->dp and control->sp may be NULL. |
| * |
| * For read the control structure contains the input row format and bit |
| * depth, the transform function changes this to represent what the |
| * transform will produce when it runs. |
| * |
| * For write the control structure contains the *required* output format |
| * and bit depth. The transform function changes this to the values that |
| * it needs to produce the required values. |
| * |
| * In both cases the transform function may update the 'fn' function to a |
| * new function to perform the desired transform; this allows considerable |
| * optimization on multi-row images. |
| * |
| * In both cases the caller considers the pixel bit depth changes and |
| * records the maximum required so that it can allocate a suitably sized |
| * buffer. |
| * |
| * 2) Execution. |
| * |
| * In the read case the transforms are processed in the stored order and |
| * must transform the row data appropriately *and* update the bit depth |
| * and format as before. |
| * |
| * In the write case the transforms are called in the reverse order and |
| * the input bit depth and format should match the required values. |
| * |
| * It is valid during initialization for the transform function to push |
| * another transform into the list in either the read or the write case if |
| * the transform cannot handle (read) or produce (write) the required format. * The transform pushes another transform into the list ahead of itself (at |
| * *transform) and runs that initialization; when control is returned to the |
| * caller the caller will re-run the transform initialization. |
| * |
| * It is also valid (during initialization) to push new transforms onto the |
| * list, just so long as the order of the transform is greater than the |
| * current transform (so that the caller will still call the new transform |
| * initialization.) |
| * |
| * In the write case the user transform callback might still end up producing |
| * an unexpected format, but at present this is unavoidable; the libpng API |
| * is extremely inconsistent in how a user transform reports the changes it |
| * made. |
| * |
| * TODO: fix this, probably with an API change in 1.7.0 |
| */ |
| typedef struct png_transform /* Linked list of transform functions */ |
| { |
| png_transformp next; /* Next transform in the list */ |
| png_transform_fn fn; /* Function to implement the transform */ |
| png_transform_free_fn free; /* Free allocated data, normally NULL */ |
| unsigned int order; /* Order of the transform in the list. */ |
| unsigned int size; /* Size of this structure (max 65535) */ |
| png_uint_32 args; /* Optional transform arguments. */ |
| } png_transform; |
| #endif /* TRANSFORM_MECH */ |
| |
| /* Action to take on CRC errors (four values) */ |
| typedef enum |
| { |
| crc_error_quit = PNG_CRC_ERROR_QUIT-1, |
| crc_warn_discard = PNG_CRC_WARN_DISCARD-1, |
| crc_warn_use = PNG_CRC_WARN_USE-1, |
| crc_quiet_use = PNG_CRC_QUIET_USE-1 |
| } png_crc_action; |
| |
| struct png_struct_def |
| { |
| /* Rearranged in libpng 1.7 to attempt to lessen padding; in general |
| * (char), (short), (int) and pointer types are kept separate; however |
| * associated members under the control of the same #define are still |
| * together. |
| */ |
| #ifdef PNG_SETJMP_SUPPORTED |
| /* jmp_buf can have very high alignment requirements on some systems, so put |
| * it first (the other setjmp members are later as they are infrequently |
| * accessed.) |
| */ |
| jmp_buf jmp_buf_local; |
| #endif /* SETJMP */ |
| |
| /* Next the frequently accessed fields. Many processors perform arithmetic |
| * in the address pipeline, but frequently the amount of addition or |
| * subtraction is limited. By putting these fields at the head of png_struct |
| * the hope is that such processors will generate code that is both smaller |
| * and faster. |
| */ |
| #ifdef PNG_READ_SUPPORTED |
| png_colorp palette; /* palette from the input file */ |
| #endif /* READ */ |
| #ifdef PNG_READ_tRNS_SUPPORTED |
| png_bytep trans_alpha; /* alpha values for paletted files */ |
| #endif /* READ_tRNS */ |
| |
| png_uint_32 width; /* width of image in pixels */ |
| png_uint_32 height; /* height of image in pixels */ |
| png_uint_32 chunk_name; /* PNG_CHUNK() id of current chunk */ |
| #ifdef PNG_READ_SUPPORTED |
| png_uint_32 chunk_length; /* Length (possibly remaining) in said chunk. */ |
| #endif /* READ */ |
| png_uint_32 crc; /* current chunk CRC value */ |
| |
| unsigned int mode :6; /* where we are in the PNG file */ |
| unsigned int read_struct :1; /* this is a read (not write) struct */ |
| unsigned int num_palette :9; /* number of color entries in palette */ |
| #ifdef PNG_READ_tRNS_SUPPORTED |
| unsigned int num_trans :9; /* number of transparency values */ |
| unsigned int transparent_palette :1; /* if they are all 0 or 255 */ |
| #endif /* READ_tRNS */ |
| #ifdef PNG_PALETTE_MAX_SUPPORTED |
| unsigned int palette_index_max :8; /* maximum palette index in IDAT */ |
| unsigned int palette_index_check :2; /* one of the following: */ |
| # define PNG_PALETTE_CHECK_DEFAULT 0U |
| # define PNG_PALETTE_CHECK_OFF 1U |
| # define PNG_PALETTE_CHECK_ON 2U |
| unsigned int palette_index_have_max :1; /* max is being set */ |
| unsigned int palette_index_check_issued :1; /* error message output */ |
| #endif /* PALETTE_MAX */ |
| #ifdef PNG_READ_tRNS_SUPPORTED |
| png_color_16 trans_color; /* transparent color for non-paletted files */ |
| #endif /* READ_tRNS */ |
| #ifdef PNG_READ_sBIT_SUPPORTED |
| png_color_8 sig_bit; /* significant bits in each channel */ |
| #endif /* READ_sBIT */ |
| |
| /* Single byte values, typically used either to save space or to hold 1-byte |
| * values from the PNG chunk specifications. |
| */ |
| png_byte filter_method; /* file filter type (only non-0 with MNG) */ |
| png_byte interlaced; /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */ |
| png_byte color_type; /* color type of file */ |
| png_byte bit_depth; /* bit depth of file */ |
| png_byte sig_bytes; /* magic bytes read/written at start of file */ |
| |
| #ifdef PNG_READ_SUPPORTED |
| #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED) |
| /* The png_struct colorspace structure is only required on read - on write it |
| * is in (just) the info_struct. |
| */ |
| png_colorspace colorspace; |
| #endif /* COLORSPACE || GAMMA */ |
| #endif /* READ */ |
| |
| /* Transform handling */ |
| #ifdef PNG_TRANSFORM_MECH_SUPPORTED |
| png_transformp transform_list; /* List of transformation to perform. */ |
| #endif /* TRANSFORM_MECH */ |
| |
| /* ROW BUFFERS and CONTROL |
| * |
| * Members used for image row compression (write) or decompression (read). |
| * filter byte (which is in next_filter.) All fields are only used during |
| * IDAT processing and start of 0. |
| */ |
| #ifdef PNG_READ_SUPPORTED |
| png_bytep row_buffer; /* primary row buffer */ |
| #if (defined(PNG_PROGRESSIVE_READ_SUPPORTED) ||\ |
| defined(PNG_READ_INTERLACING_SUPPORTED)) &&\ |
| defined(PNG_TRANSFORM_MECH_SUPPORTED) |
| png_bytep transformed_row; /* pointer to the transformed row, if |
| * required. May point to row_buffer. |
| */ |
| #endif /* (PROGRESSIVE_READ || READ_INTERLACING) && TRANSFORM_MECH */ |
| |
| png_alloc_size_t row_bytes_read; /* Total read in row */ |
| #endif /* READ */ |
| |
| png_uint_32 row_number; /* current row in pass */ |
| #ifdef PNG_READ_SUPPORTED |
| #ifdef PNG_READ_GAMMA_SUPPORTED |
| png_fixed_point row_gamma; /* Gamma of final output */ |
| #if 0 /* NYI */ |
| unsigned int gamma_accuracy; |
| /* LINEAR gamma cache table size (in bits) times 100; for non-linear |
| * tables the value used is gamma_accuracy/gamma where 'gamma' is the |
| * encoding value of the data (typically less than 1). |
| * |
| * default: PNG_DEFAULT_GAMMA_ACCURACY (665) |
| */ |
| #endif /* NYI */ |
| png_uint_16 gamma_threshold; |
| /* Gamma threshold value as a fixed-point value in the range 0..1; the |
| * threshold at or below which gamma correction is skipped. '0' forces |
| * gamma correction even when there is none because the input and output |
| * gammas are equal. |
| * |
| * default: PNG_GAMMA_THRESHOLD_FIXED (153) |
| */ |
| #endif /* READ_GAMMA */ |
| #ifdef PNG_READ_TRANSFORMS_SUPPORTED |
| unsigned int invalid_info; /* PNG_INFO_* for invalidated chunks */ |
| unsigned int palette_updated:1; /* png_struct::palette changed */ |
| #endif /* READ_TRANSFORMS */ |
| #ifdef PNG_SEQUENTIAL_READ_SUPPORTED |
| unsigned int read_started :1; /* at least one call to png_read_row */ |
| #endif /* SEQUENTIAL_READ */ |
| /* The next field is just used by the read IDAT process functions to store |
| * the state of IDAT processing; they should not be altered or used by other |
| * functions. |
| */ |
| unsigned int row_state :2; /* state of row parsing (internal) */ |
| #endif /* READ */ |
| |
| #if defined (PNG_READ_INTERLACING_SUPPORTED) ||\ |
| defined (PNG_WRITE_INTERLACING_SUPPORTED) |
| unsigned int do_interlace :1; /* libpng handles the interlace */ |
| # endif /* R/W INTERLACING */ |
| |
| unsigned int pass :3; /* current (interlace) pass (0 - 6) */ |
| |
| /* The following fields are set by png_row_init to the pixel depths of the |
| * pixels at various states. If transforms are not supported they will |
| * always be the same value: |
| * |
| * READ WRITE |
| * input: PNG From application |
| * output: To application PNG |
| * max: Largest in transform |
| */ |
| unsigned int row_input_pixel_depth :8; |
| unsigned int row_output_pixel_depth :8; |
| unsigned int row_max_pixel_depth :8; |
| |
| # define PNG_RF_BITS 9 /* Number of bits required for the row format (below) */ |
| #ifdef PNG_TRANSFORM_MECH_SUPPORTED |
| /* The following fields describe the format of the user row; the output on |
| * read or the input on write, and give the maximum pixel depth, which |
| * controls the row buffer allocation size (row_allocated_bytes) above. |
| */ |
| unsigned int row_range :3; /* range error count */ |
| unsigned int row_bit_depth :6; /* bits per channel (up to 32) */ |
| unsigned int row_format:PNG_RF_BITS;/* format of output(R)/input(W) row: */ |
| /* PNG_FORMAT_FLAG_ALPHA 0x01U format with an alpha channel |
| * PNG_FORMAT_FLAG_COLOR 0x02U color format: otherwise grayscale |
| * PNG_FORMAT_FLAG_LINEAR 0x04U NOT used (informational) |
| * PNG_FORMAT_FLAG_COLORMAP 0x08U image data is color-mapped |
| * PNG_FORMAT_FLAG_BGR 0x10U BGR colors, else order is RGB |
| * PNG_FORMAT_FLAG_AFIRST 0x20U alpha channel comes first * |
| * PNG_FORAMT_FLAG_AFILLER 0x40U The 'alpha' channel is a filler: |
| * PNG_FORMAT_FLAG_ALPHA is set however the value in the alpha channel |
| * is not an alpha value and (therefore) cannot be used for alpha |
| * computations, it is just a filler value. PNG_COLOR_TYPE_FROM_FORMAT |
| * will return a color type *without* PNG_COLOR_MASK_ALPHA, however |
| * PNG_FORMAT_CHANNELS will return the correct number, including the |
| * filler channel. |
| * PNG_FORMAT_FLAG_SWAPPED 0x80U bytes or bits swapped: |
| * When the bit depth is 16 this means that the bytes within the |
| * components have been swapped, when the bit depth is less than 8 |
| * it means the pixels within the bytes have been swapped. It should |
| * not be set for 8-bit compononents (it is meaningless). |
| * PNG_FORMAT_FLAG_RANGE 0x100U component range not 0..bit-depth: |
| * Low-bit-depth grayscale components have been unpacked into bytes |
| * without scaling, or RGB[A] pixels have been shifted back to the |
| * significant-bit range from the sBIT chunk or channels (currently |
| * alpha or gray) have been inverted. |
| * PNG_FORMAT_FLAG_INVALID NOT STORED HERE |
| */ |
| #ifdef PNG_WRITE_TRANSFORMS_SUPPORTED |
| unsigned int info_format:PNG_RF_BITS; |
| /* This field is used to validate the png_info used to write the |
| * IHDR. This is a new check in 1.7.0; previously it was possible to pass |
| * a png_info from a png_read with the read tranform information in the |
| * format having manually removed the required transforms from the rows |
| * passed to png_write_row. |
| */ |
| #endif /* WRITE_TRANSFORMS */ |
| #ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED |
| unsigned int write_invert_alpha :1; |
| /* This indicates the png_set_invert_alpha was called, it is used by the |
| * write code to implement the transform without needing to run the whole |
| * transform mechanism on the PNG palette data. |
| */ |
| #endif /* WRITE_INVERT_ALPHA */ |
| #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED |
| unsigned int rgb_to_gray_status :1; |
| /* If set an RGB pixel was encountered by the RGB to gray transform |
| * wherein !(r==g==b). |
| */ |
| #endif /* RGB_TO_GRAY */ |
| #endif /* TRANSFORM_MECH */ |
| |
| #ifdef PNG_READ_SUPPORTED |
| /* These, and IDAT_size below, control how much input and output (at most) is |
| * available to zlib during read decompression. |
| */ |
| png_alloc_size_t read_buffer_size; /* current size of the buffer */ |
| #endif /* READ */ |
| |
| #if defined(PNG_SEQUENTIAL_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) |
| png_uint_32 IDAT_size; /* limit on IDAT read and write IDAT size */ |
| #endif /* SEQUENTIAL_READ || WRITE */ |
| |
| /* ERROR HANDLING */ |
| #ifdef PNG_SETJMP_SUPPORTED |
| jmp_buf *jmp_buf_ptr; /* passed to longjmp_fn */ |
| png_longjmp_ptr longjmp_fn; /* setjmp non-local goto function. */ |
| size_t jmp_buf_size; /* size of *jmp_buf_ptr, if allocated */ |
| #endif /* SETJMP */ |
| |
| /* Error/warning callbacks */ |
| png_error_ptr error_fn; /* print an error message and abort */ |
| #ifdef PNG_WARNINGS_SUPPORTED |
| png_error_ptr warning_fn; /* print a warning and continue */ |
| #endif /* WARNINGS */ |
| png_voidp error_ptr; /* user supplied data for the above */ |
| |
| /* MEMORY ALLOCATION */ |
| #ifdef PNG_USER_MEM_SUPPORTED |
| png_malloc_ptr malloc_fn; /* allocate memory */ |
| png_free_ptr free_fn; /* free memory */ |
| png_voidp mem_ptr; /* user supplied data for the above */ |
| #endif /* USER_MEM */ |
| |
| /* IO and BASIC READ/WRITE SUPPORT */ |
| png_voidp io_ptr; /* user supplied data for IO callbacks */ |
| png_rw_ptr rw_data_fn; /* read/write some bytes (must succeed) */ |
| |
| #ifdef PNG_READ_SUPPORTED |
| png_read_status_ptr read_row_fn; /* called after each row is decoded */ |
| png_bytep read_buffer; /* buffer for reading chunk data */ |
| |
| /* During read the following array is set up to point to the appropriate |
| * un-filter function, this allows per-image and per-processor optimization. |
| */ |
| void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_alloc_size_t row_bytes, |
| unsigned int bpp, png_bytep row, png_const_bytep prev_row, |
| png_const_bytep prev_pixels); |
| #endif /* READ */ |
| |
| #ifdef PNG_WRITE_SUPPORTED |
| png_write_status_ptr write_row_fn; /* called after each row is encoded */ |
| |
| #ifdef PNG_WRITE_FLUSH_SUPPORTED |
| png_flush_ptr output_flush_fn; /* Function for flushing output */ |
| #endif /* WRITE_FLUSH */ |
| #endif /* WRITE */ |
| |
| #ifdef PNG_SET_USER_LIMITS_SUPPORTED |
| png_uint_32 user_width_max; /* Maximum width on read */ |
| png_uint_32 user_height_max; /* Maximum height on read */ |
| /* Total memory that a single zTXt, sPLT, iTXt, iCCP, or unknown chunk |
| * can occupy when decompressed. 0 means unlimited. This field is a counter |
| * - it is decremented as memory is allocated. |
| */ |
| png_alloc_size_t user_chunk_malloc_max; |
| #endif /* SET_USER_LIMITS */ |
| #ifdef PNG_USER_LIMITS_SUPPORTED |
| /* limit on total *number* of sPLT, text and unknown chunks that can be |
| * stored. 0 means unlimited. This field is a counter - it is decremented |
| * as chunks are encountered. |
| */ |
| png_uint_32 user_chunk_cache_max; |
| #endif /* USER_LIMITS */ |
| |
| /* The progressive reader gets passed data and calls application handling |
| * functions when appropriate. |
| */ |
| #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 row is decoded */ |
| png_progressive_end_ptr end_fn; /* called after image is complete */ |
| |
| /* Progressive read control data */ |
| 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 */ |
| |
| size_t save_buffer_size; /* amount of data now in save_buffer */ |
| size_t save_buffer_max; /* total size of save_buffer */ |
| size_t current_buffer_size; /* amount of data now in current_buffer */ |
| size_t buffer_size; /* total amount of available input data */ |
| |
| unsigned int process_mode :8; |
| /* This is one or two four bit codes describing the current state of the |
| * 'push' reader. Normally the low four bits are a state code, however in |
| * some cases this may be pushed to the top four bits and replaced by a |
| * different temporary state code. The value is, in effect, a two entry |
| * stack. |
| */ |
| #endif /* PROGRESSIVE_READ */ |
| |
| #ifdef PNG_IO_STATE_SUPPORTED |
| png_uint_32 io_state; /* tells the app read/write progress */ |
| #endif /* IO_STATE */ |
| |
| /* UNKNOWN CHUNK HANDLING */ |
| /* TODO: this is excessively complicated, there are multiple ways of doing |
| * the same thing. It should be cleaned up, possibly by finding out which |
| * APIs applications really use. |
| */ |
| #ifdef PNG_USER_CHUNKS_SUPPORTED |
| /* General purpose pointer for all user/unknown chunk handling; points to |
| * application supplied data for use in the read_user_chunk_fn callback |
| * (currently there is no write side support - the write side must use the |
| * set_unknown_chunks interface.) |
| */ |
| png_voidp user_chunk_ptr; |
| #endif /* USER_CHUNKS */ |
| |
| #ifdef PNG_READ_USER_CHUNKS_SUPPORTED |
| /* This is called back from the unknown chunk handling */ |
| png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */ |
| #endif /* READ_USER_CHUNKS */ |
| |
| #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED |
| png_uint_32 known_unknown; /* Bit mask of known chunks to be treated as |
| * unknown in the read code. |
| */ |
| #ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED |
| png_uint_32 save_unknown; /* Whether to save or skip these chunks: |
| * 'save' is 'known & save', 'skip' is |
| * 'known & ~save'. |
| */ |
| # define png_IDATs_skipped(pp) (((pp)->known_unknown & ~(pp)->save_unknown)&1U) |
| #else /* !SAVE_UNKNOWN_CHUNKS */ |
| # define png_IDATs_skipped(pp) ((pp)->known_unknown & 1U) |
| #endif /* !SAVE_UNKNOWN_CHUNKS */ |
| #endif /* HANDLE_AS_UNKNOWN */ |
| |
| #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED |
| png_bytep chunk_list; /* List of png_byte[5]; the textual chunk name |
| * followed by a PNG_HANDLE_* byte */ |
| unsigned int unknown_default :2; /* As PNG_HANDLE_* */ |
| unsigned int num_chunk_list; /* Number of entries in the list */ |
| #endif /* SET_UNKNOWN_CHUNKS */ |
| |
| /* COMPRESSION AND DECOMPRESSION SUPPORT. |
| * |
| * zlib expects a 'zstream' as the fundamental control structure, it allows |
| * all the parameters to be passed as one pointer. |
| */ |
| png_uint_32 zowner; /* ID (chunk type) of zlib owner, 0 if none */ |
| # ifdef PNG_WRITE_SUPPORTED |
| png_zlib_statep zlib_state; /* State of zlib compression */ |
| # endif /* WRITE */ |
| # ifdef PNG_READ_SUPPORTED |
| z_stream zstream; /* decompression structure */ |
| unsigned int zstream_ended:1; /* no more zlib output available [read] */ |
| unsigned int zstream_error:1; /* zlib error message has been output [read] */ |
| # endif /* READ */ |
| # ifdef PNG_PROGRESSIVE_READ_SUPPORTED |
| unsigned int zstream_eod :1; /* all the required uncompressed data has been |
| * received; set by the zstream using code for |
| * its own purposes. [progressive read] */ |
| # endif /* PROGRESSIVE_READ */ |
| # ifdef PNG_BENIGN_ERRORS_SUPPORTED |
| unsigned int benign_error_action :2; |
| unsigned int app_warning_action :2; |
| unsigned int app_error_action :2; |
| # ifdef PNG_READ_SUPPORTED |
| unsigned int IDAT_error_action :2; |
| # endif /* READ */ |
| # endif /* BENIGN_ERRORS */ |
| # ifdef PNG_READ_SUPPORTED |
| /* CRC checking actions, one for critical chunks, one for ancillary |
| * chunks. |
| */ |
| unsigned int critical_crc :2; |
| unsigned int ancillary_crc :2; |
| unsigned int current_crc :2; /* Cache of one or other of the above */ |
| # endif |
| # ifdef PNG_SET_OPTION_SUPPORTED |
| # ifdef PNG_READ_SUPPORTED |
| unsigned int maximum_inflate_window :1U; |
| # endif /* READ */ |
| unsigned int skip_sRGB_profile_check :1U; |
| # endif /* SET_OPTION */ |
| |
| /* MNG SUPPORT */ |
| #ifdef PNG_MNG_FEATURES_SUPPORTED |
| unsigned int mng_features_permitted :3; |
| #endif /* MNG_FEATURES */ |
| |
| /* SCRATCH buffers, used when control returns to the application or a read |
| * loop. |
| */ |
| # ifdef PNG_READ_SUPPORTED |
| png_byte scratch[PNG_ROW_BUFFER_SIZE+16U]; |
| # endif /* READ */ |
| }; |
| #endif /* PNGSTRUCT_H */ |
