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pngpriv.h
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pngpriv.h
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/* pngpriv.h - private declarations for use inside libpng
*
* For conditions of distribution and use, see copyright notice in png.h
* Copyright (c) 1998-2012 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 1.5.10 [March 29, 2012]
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
*/
/* The symbols declared in this file (including the functions declared
* as PNG_EXTERN) are PRIVATE. They are not part of the libpng public
* interface, and are not recommended for use by regular applications.
* Some of them may become public in the future; others may stay private,
* change in an incompatible way, or even disappear.
* Although the libpng users are not forbidden to include this header,
* they should be well aware of the issues that may arise from doing so.
*/
#ifndef PNGPRIV_H
#define PNGPRIV_H
/* Feature Test Macros. The following are defined here to ensure that correctly
* implemented libraries reveal the APIs libpng needs to build and hide those
* that are not needed and potentially damaging to the compilation.
*
* Feature Test Macros must be defined before any system header is included (see
* POSIX 1003.1 2.8.2 "POSIX Symbols."
*
* These macros only have an effect if the operating system supports either
* POSIX 1003.1 or C99, or both. On other operating systems (particularly
* Windows/Visual Studio) there is no effect; the OS specific tests below are
* still required (as of 2011-05-02.)
*/
#define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
/* This is required for the definition of abort(), used as a last ditch
* error handler when all else fails.
*/
#include <stdlib.h>
/* This is used to find 'offsetof', used below for alignment tests. */
#include <stddef.h>
#define PNGLIB_BUILD /*libpng is being built, not used*/
#ifdef PNG_USER_CONFIG
# include "pngusr.h"
/* These should have been defined in pngusr.h */
# ifndef PNG_USER_PRIVATEBUILD
# define PNG_USER_PRIVATEBUILD "Custom libpng build"
# endif
# ifndef PNG_USER_DLLFNAME_POSTFIX
# define PNG_USER_DLLFNAME_POSTFIX "Cb"
# endif
#endif
/* Is this a build of a DLL where compilation of the object modules requires
* different preprocessor settings to those required for a simple library? If
* so PNG_BUILD_DLL must be set.
*
* If libpng is used inside a DLL but that DLL does not export the libpng APIs
* PNG_BUILD_DLL must not be set. To avoid the code below kicking in build a
* static library of libpng then link the DLL against that.
*/
#ifndef PNG_BUILD_DLL
# ifdef DLL_EXPORT
/* This is set by libtool when files are compiled for a DLL; libtool
* always compiles twice, even on systems where it isn't necessary. Set
* PNG_BUILD_DLL in case it is necessary:
*/
# define PNG_BUILD_DLL
# else
# ifdef _WINDLL
/* This is set by the Microsoft Visual Studio IDE in projects that
* build a DLL. It can't easily be removed from those projects (it
* isn't visible in the Visual Studio UI) so it is a fairly reliable
* indication that PNG_IMPEXP needs to be set to the DLL export
* attributes.
*/
# define PNG_BUILD_DLL
# else
# ifdef __DLL__
/* This is set by the Borland C system when compiling for a DLL
* (as above.)
*/
# define PNG_BUILD_DLL
# else
/* Add additional compiler cases here. */
# endif
# endif
# endif
#endif /* Setting PNG_BUILD_DLL if required */
/* See pngconf.h for more details: the builder of the library may set this on
* the command line to the right thing for the specific compilation system or it
* may be automagically set above (at present we know of no system where it does
* need to be set on the command line.)
*
* PNG_IMPEXP must be set here when building the library to prevent pngconf.h
* setting it to the "import" setting for a DLL build.
*/
#ifndef PNG_IMPEXP
# ifdef PNG_BUILD_DLL
# define PNG_IMPEXP PNG_DLL_EXPORT
# else
/* Not building a DLL, or the DLL doesn't require specific export
* definitions.
*/
# define PNG_IMPEXP
# endif
#endif
/* No warnings for private or deprecated functions in the build: */
#ifndef PNG_DEPRECATED
# define PNG_DEPRECATED
#endif
#ifndef PNG_PRIVATE
# define PNG_PRIVATE
#endif
#include "png.h"
#include "pnginfo.h"
#include "pngstruct.h"
/* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
#ifndef PNG_DLL_EXPORT
# define PNG_DLL_EXPORT
#endif
/* SECURITY and SAFETY:
*
* By default libpng is built without any internal limits on image size,
* individual heap (png_malloc) allocations or the total amount of memory used.
* If PNG_SAFE_LIMITS_SUPPORTED is defined, however, the limits below are used
* (unless individually overridden). These limits are believed to be fairly
* safe, but builders of secure systems should verify the values against the
* real system capabilities.
*/
#ifdef PNG_SAFE_LIMITS_SUPPORTED
/* 'safe' limits */
# ifndef PNG_USER_WIDTH_MAX
# define PNG_USER_WIDTH_MAX 1000000
# endif
# ifndef PNG_USER_HEIGHT_MAX
# define PNG_USER_HEIGHT_MAX 1000000
# endif
# ifndef PNG_USER_CHUNK_CACHE_MAX
# define PNG_USER_CHUNK_CACHE_MAX 128
# endif
# ifndef PNG_USER_CHUNK_MALLOC_MAX
# define PNG_USER_CHUNK_MALLOC_MAX 8000000
# endif
#else
/* values for no limits */
# ifndef PNG_USER_WIDTH_MAX
# define PNG_USER_WIDTH_MAX 0x7fffffff
# endif
# ifndef PNG_USER_HEIGHT_MAX
# define PNG_USER_HEIGHT_MAX 0x7fffffff
# endif
# ifndef PNG_USER_CHUNK_CACHE_MAX
# define PNG_USER_CHUNK_CACHE_MAX 0
# endif
# ifndef PNG_USER_CHUNK_MALLOC_MAX
# define PNG_USER_CHUNK_MALLOC_MAX 0
# endif
#endif
/* This is used for 16 bit gamma tables - only the top level pointers are const,
* this could be changed:
*/
typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
/* Added at libpng-1.2.9 */
/* Moved to pngpriv.h at libpng-1.5.0 */
/* config.h is created by and PNG_CONFIGURE_LIBPNG is set by the "configure"
* script. We may need it here to get the correct configuration on things
* like limits.
*/
#ifdef PNG_CONFIGURE_LIBPNG
# ifdef HAVE_CONFIG_H
# include "config.h"
# endif
#endif
/* Moved to pngpriv.h at libpng-1.5.0 */
/* NOTE: some of these may have been used in external applications as
* these definitions were exposed in pngconf.h prior to 1.5.
*/
/* If you are running on a machine where you cannot allocate more
* than 64K of memory at once, uncomment this. While libpng will not
* normally need that much memory in a chunk (unless you load up a very
* large file), zlib needs to know how big of a chunk it can use, and
* libpng thus makes sure to check any memory allocation to verify it
* will fit into memory.
*
* zlib provides 'MAXSEG_64K' which, if defined, indicates the
* same limit and pngconf.h (already included) sets the limit
* if certain operating systems are detected.
*/
#if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
# define PNG_MAX_MALLOC_64K
#endif
#ifndef PNG_UNUSED
/* Unused formal parameter warnings are silenced using the following macro
* which is expected to have no bad effects on performance (optimizing
* compilers will probably remove it entirely). Note that if you replace
* it with something other than whitespace, you must include the terminating
* semicolon.
*/
# define PNG_UNUSED(param) (void)param;
#endif
/* Just a little check that someone hasn't tried to define something
* contradictory.
*/
#if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
# undef PNG_ZBUF_SIZE
# define PNG_ZBUF_SIZE 65536L
#endif
/* PNG_STATIC is used to mark internal file scope functions if they need to be
* accessed for implementation tests (see the code in tests/?*).
*/
#ifndef PNG_STATIC
# define PNG_STATIC static
#endif
/* C99 restrict is used where possible, to do this 'restrict' is defined as
* empty if we can't be sure it is supported. configure builds have already
* done this work.
*/
#ifdef PNG_CONFIGURE_LIBPNG
# define PNG_RESTRICT restrict
#else
/* Modern compilers support restrict, but assume not for anything not
* recognized here:
*/
# if defined __GNUC__ || defined _MSC_VER || defined __WATCOMC__
# define PNG_RESTRICT restrict
# else
# define PNG_RESTRICT
# endif
#endif
/* If warnings or errors are turned off the code is disabled or redirected here.
* From 1.5.4 functions have been added to allow very limited formatting of
* error and warning messages - this code will also be disabled here.
*/
#ifdef PNG_WARNINGS_SUPPORTED
# define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
#else
# define png_warning(s1,s2) ((void)(s1))
# define png_chunk_warning(s1,s2) ((void)(s1))
# define png_warning_parameter(p,number,string) ((void)0)
# define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
# define png_warning_parameter_signed(p,number,format,value) ((void)0)
# define png_formatted_warning(pp,p,message) ((void)(pp))
# define PNG_WARNING_PARAMETERS(p)
#endif
#ifndef PNG_ERROR_TEXT_SUPPORTED
# define png_error(s1,s2) png_err(s1)
# define png_chunk_error(s1,s2) png_err(s1)
# define png_fixed_error(s1,s2) png_err(s1)
#endif
/* C allows up-casts from (void*) to any pointer and (const void*) to any
* pointer to a const object. C++ regards this as a type error and requires an
* explicit, static, cast and provides the static_cast<> rune to ensure that
* const is not cast away.
*/
#ifdef __cplusplus
# define png_voidcast(type, value) static_cast<type>(value)
#else
# define png_voidcast(type, value) (value)
#endif /* __cplusplus */
#ifndef PNG_EXTERN
/* The functions exported by PNG_EXTERN are internal functions, which
* aren't usually used outside the library (as far as I know), so it is
* debatable if they should be exported at all. In the future, when it
* is possible to have run-time registry of chunk-handling functions,
* some of these might be made available again.
*
* 1.5.7: turned the use of 'extern' back on, since it is localized to pngpriv.h
* it should be safe now (it is unclear why it was turned off.)
*/
# define PNG_EXTERN extern
#endif
/* Some fixed point APIs are still required even if not exported because
* they get used by the corresponding floating point APIs. This magic
* deals with this:
*/
#ifdef PNG_FIXED_POINT_SUPPORTED
# define PNGFAPI PNGAPI
#else
# define PNGFAPI /* PRIVATE */
#endif
/* Other defines specific to compilers can go here. Try to keep
* them inside an appropriate ifdef/endif pair for portability.
*/
#if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
/* png.c requires the following ANSI-C constants if the conversion of
* floating point to ASCII is implemented therein:
*
* DBL_DIG Maximum number of decimal digits (can be set to any constant)
* DBL_MIN Smallest normalized fp number (can be set to an arbitrary value)
* DBL_MAX Maximum floating point number (can be set to an arbitrary value)
*/
# include <float.h>
# if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
/* We need to check that <math.h> hasn't already been included earlier
* as it seems it doesn't agree with <fp.h>, yet we should really use
* <fp.h> if possible.
*/
# if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
# include <fp.h>
# endif
# else
# include <math.h>
# endif
# if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
/* Amiga SAS/C: We must include builtin FPU functions when compiling using
* MATH=68881
*/
# include <m68881.h>
# endif
#endif
/* This provides the non-ANSI (far) memory allocation routines. */
#if defined(__TURBOC__) && defined(__MSDOS__)
# include <mem.h>
# include <alloc.h>
#endif
#if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
defined(_WIN32) || defined(__WIN32__)
# include <windows.h> /* defines _WINDOWS_ macro */
#endif
/* Moved here around 1.5.0beta36 from pngconf.h */
/* Users may want to use these so they are not private. Any library
* functions that are passed far data must be model-independent.
*/
/* Memory model/platform independent fns */
#ifndef PNG_ABORT
# ifdef _WINDOWS_
# define PNG_ABORT() ExitProcess(0)
# else
# define PNG_ABORT() abort()
# endif
#endif
#ifdef USE_FAR_KEYWORD
/* Use this to make far-to-near assignments */
# define CHECK 1
# define NOCHECK 0
# define CVT_PTR(ptr) (png_far_to_near(png_ptr,ptr,CHECK))
# define CVT_PTR_NOCHECK(ptr) (png_far_to_near(png_ptr,ptr,NOCHECK))
# define png_strlen _fstrlen
# define png_memcmp _fmemcmp /* SJT: added */
# define png_memcpy _fmemcpy
# define png_memset _fmemset
#else
# ifdef _WINDOWS_ /* Favor Windows over C runtime fns */
# define CVT_PTR(ptr) (ptr)
# define CVT_PTR_NOCHECK(ptr) (ptr)
# define png_strlen lstrlenA
# define png_memcmp memcmp
# define png_memcpy CopyMemory
# define png_memset memset
# else
# define CVT_PTR(ptr) (ptr)
# define CVT_PTR_NOCHECK(ptr) (ptr)
# define png_strlen strlen
# define png_memcmp memcmp /* SJT: added */
# define png_memcpy memcpy
# define png_memset memset
# endif
#endif
/* These macros may need to be architecture dependent. */
#define PNG_ALIGN_NONE 0 /* do not use data alignment */
#define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */
#ifdef offsetof
# define PNG_ALIGN_OFFSET 2 /* use offsetof to determine alignment */
#else
# define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
#endif
#define PNG_ALIGN_SIZE 3 /* use sizeof to determine alignment */
#ifndef PNG_ALIGN_TYPE
/* Default to using aligned access optimizations and requiring alignment to a
* multiple of the data type size. Override in a compiler specific fashion
* if necessary by inserting tests here:
*/
# define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
#endif
#if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
/* This is used because in some compiler implementations non-aligned
* structure members are supported, so the offsetof approach below fails.
* Set PNG_ALIGN_TO_SIZE=0 for compiler combinations where unaligned access
* is good for performance. Do not do this unless you have tested the result
* and understand it.
*/
# define png_alignof(type) (sizeof (type))
#else
# if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
# define png_alignof(type) offsetof(struct{char c; type t;}, t)
# else
# if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
# define png_alignof(type) (1)
# endif
/* Else leave png_alignof undefined to prevent use thereof */
# endif
#endif
/* This implicitly assumes alignment is always to a power of 2. */
#ifdef png_alignof
# define png_isaligned(ptr, type)\
((((const char*)ptr-(const char*)0) & (png_alignof(type)-1)) == 0)
#else
# define png_isaligned(ptr, type) 0
#endif
/* End of memory model/platform independent support */
/* End of 1.5.0beta36 move from pngconf.h */
/* CONSTANTS and UTILITY MACROS
* These are used internally by libpng and not exposed in the API
*/
/* Various modes of operation. Note that after an init, mode is set to
* zero automatically when the structure is created. Three of these
* are defined in png.h because they need to be visible to applications
* that call png_set_unknown_chunk().
*/
/* #define PNG_HAVE_IHDR 0x01 (defined in png.h) */
/* #define PNG_HAVE_PLTE 0x02 (defined in png.h) */
#define PNG_HAVE_IDAT 0x04
/* #define PNG_AFTER_IDAT 0x08 (defined in png.h) */
#define PNG_HAVE_IEND 0x10
#define PNG_HAVE_gAMA 0x20
#define PNG_HAVE_cHRM 0x40
#define PNG_HAVE_sRGB 0x80
#define PNG_HAVE_CHUNK_HEADER 0x100
#define PNG_WROTE_tIME 0x200
#define PNG_WROTE_INFO_BEFORE_PLTE 0x400
#define PNG_BACKGROUND_IS_GRAY 0x800
#define PNG_HAVE_PNG_SIGNATURE 0x1000
#define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
#define PNG_HAVE_iCCP 0x4000
#ifdef PNG_APNG_SUPPORTED
#define PNG_HAVE_acTL 0x8000
#define PNG_HAVE_fcTL 0x10000
#endif
/* Flags for the transformations the PNG library does on the image data */
#define PNG_BGR 0x0001
#define PNG_INTERLACE 0x0002
#define PNG_PACK 0x0004
#define PNG_SHIFT 0x0008
#define PNG_SWAP_BYTES 0x0010
#define PNG_INVERT_MONO 0x0020
#define PNG_QUANTIZE 0x0040
#define PNG_COMPOSE 0x0080 /* Was PNG_BACKGROUND */
#define PNG_BACKGROUND_EXPAND 0x0100
#define PNG_EXPAND_16 0x0200 /* Added to libpng 1.5.2 */
#define PNG_16_TO_8 0x0400 /* Becomes 'chop' in 1.5.4 */
#define PNG_RGBA 0x0800
#define PNG_EXPAND 0x1000
#define PNG_GAMMA 0x2000
#define PNG_GRAY_TO_RGB 0x4000
#define PNG_FILLER 0x8000
#define PNG_PACKSWAP 0x10000
#define PNG_SWAP_ALPHA 0x20000
#define PNG_STRIP_ALPHA 0x40000
#define PNG_INVERT_ALPHA 0x80000
#define PNG_USER_TRANSFORM 0x100000
#define PNG_RGB_TO_GRAY_ERR 0x200000
#define PNG_RGB_TO_GRAY_WARN 0x400000
#define PNG_RGB_TO_GRAY 0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */
#define PNG_ENCODE_ALPHA 0x800000 /* Added to libpng-1.5.4 */
#define PNG_ADD_ALPHA 0x1000000 /* Added to libpng-1.2.7 */
#define PNG_EXPAND_tRNS 0x2000000 /* Added to libpng-1.2.9 */
#define PNG_SCALE_16_TO_8 0x4000000 /* Added to libpng-1.5.4 */
/* 0x8000000 unused */
/* 0x10000000 unused */
/* 0x20000000 unused */
/* 0x40000000 unused */
/* Flags for png_create_struct */
#define PNG_STRUCT_PNG 0x0001
#define PNG_STRUCT_INFO 0x0002
/* Scaling factor for filter heuristic weighting calculations */
#define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))
#define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))
/* Flags for the png_ptr->flags rather than declaring a byte for each one */
#define PNG_FLAG_ZLIB_CUSTOM_STRATEGY 0x0001
#define PNG_FLAG_ZLIB_CUSTOM_LEVEL 0x0002
#define PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL 0x0004
#define PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS 0x0008
#define PNG_FLAG_ZLIB_CUSTOM_METHOD 0x0010
#define PNG_FLAG_ZLIB_FINISHED 0x0020
#define PNG_FLAG_ROW_INIT 0x0040
#define PNG_FLAG_FILLER_AFTER 0x0080
#define PNG_FLAG_CRC_ANCILLARY_USE 0x0100
#define PNG_FLAG_CRC_ANCILLARY_NOWARN 0x0200
#define PNG_FLAG_CRC_CRITICAL_USE 0x0400
#define PNG_FLAG_CRC_CRITICAL_IGNORE 0x0800
#define PNG_FLAG_ASSUME_sRGB 0x1000 /* Added to libpng-1.5.4 */
#define PNG_FLAG_OPTIMIZE_ALPHA 0x2000 /* Added to libpng-1.5.4 */
#define PNG_FLAG_DETECT_UNINITIALIZED 0x4000 /* Added to libpng-1.5.4 */
#define PNG_FLAG_KEEP_UNKNOWN_CHUNKS 0x8000
#define PNG_FLAG_KEEP_UNSAFE_CHUNKS 0x10000
#define PNG_FLAG_LIBRARY_MISMATCH 0x20000
#define PNG_FLAG_STRIP_ERROR_NUMBERS 0x40000
#define PNG_FLAG_STRIP_ERROR_TEXT 0x80000
#define PNG_FLAG_MALLOC_NULL_MEM_OK 0x100000
/* 0x200000 unused */
/* 0x400000 unused */
#define PNG_FLAG_BENIGN_ERRORS_WARN 0x800000 /* Added to libpng-1.4.0 */
#define PNG_FLAG_ZTXT_CUSTOM_STRATEGY 0x1000000 /* 5 lines added */
#define PNG_FLAG_ZTXT_CUSTOM_LEVEL 0x2000000 /* to libpng-1.5.4 */
#define PNG_FLAG_ZTXT_CUSTOM_MEM_LEVEL 0x4000000
#define PNG_FLAG_ZTXT_CUSTOM_WINDOW_BITS 0x8000000
#define PNG_FLAG_ZTXT_CUSTOM_METHOD 0x10000000
/* 0x20000000 unused */
/* 0x40000000 unused */
#define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
PNG_FLAG_CRC_ANCILLARY_NOWARN)
#define PNG_FLAG_CRC_CRITICAL_MASK (PNG_FLAG_CRC_CRITICAL_USE | \
PNG_FLAG_CRC_CRITICAL_IGNORE)
#define PNG_FLAG_CRC_MASK (PNG_FLAG_CRC_ANCILLARY_MASK | \
PNG_FLAG_CRC_CRITICAL_MASK)
/* 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
/* Save typing and make code easier to understand */
#define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
abs((int)((c1).green) - (int)((c2).green)) + \
abs((int)((c1).blue) - (int)((c2).blue)))
/* Added to libpng-1.2.6 JB */
#define PNG_ROWBYTES(pixel_bits, width) \
((pixel_bits) >= 8 ? \
((png_size_t)(width) * (((png_size_t)(pixel_bits)) >> 3)) : \
(( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) )
/* PNG_OUT_OF_RANGE returns true if value is outside the range
* ideal-delta..ideal+delta. Each argument is evaluated twice.
* "ideal" and "delta" should be constants, normally simple
* integers, "value" a variable. Added to libpng-1.2.6 JB
*/
#define PNG_OUT_OF_RANGE(value, ideal, delta) \
( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
/* Conversions between fixed and floating point, only defined if
* required (to make sure the code doesn't accidentally use float
* when it is supposedly disabled.)
*/
#ifdef PNG_FLOATING_POINT_SUPPORTED
/* The floating point conversion can't overflow, though it can and
* does lose accuracy relative to the original fixed point value.
* In practice this doesn't matter because png_fixed_point only
* stores numbers with very low precision. The png_ptr and s
* arguments are unused by default but are there in case error
* checking becomes a requirement.
*/
#define png_float(png_ptr, fixed, s) (.00001 * (fixed))
/* The fixed point conversion performs range checking and evaluates
* its argument multiple times, so must be used with care. The
* range checking uses the PNG specification values for a signed
* 32 bit fixed point value except that the values are deliberately
* rounded-to-zero to an integral value - 21474 (21474.83 is roughly
* (2^31-1) * 100000). 's' is a string that describes the value being
* converted.
*
* NOTE: this macro will raise a png_error if the range check fails,
* therefore it is normally only appropriate to use this on values
* that come from API calls or other sources where an out of range
* error indicates a programming error, not a data error!
*
* NOTE: by default this is off - the macro is not used - because the
* function call saves a lot of code.
*/
#ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
#define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
#else
PNG_EXTERN png_fixed_point png_fixed PNGARG((png_structp png_ptr, double fp,
png_const_charp text));
#endif
#endif
/* Constants for known chunk types. If you need to add a chunk, define the name
* here. For historical reasons these constants have the form png_<name>; i.e.
* the prefix is lower case. Please use decimal values as the parameters to
* match the ISO PNG specification and to avoid relying on the C locale
* interpretation of character values.
*
* Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
* are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
* to be generated if required.
*
* PNG_32b correctly produces a value shifted by up to 24 bits, even on
* architectures where (int) is only 16 bits.
*/
#define PNG_32b(b,s) ((png_uint_32)(b) << (s))
#define PNG_CHUNK(b1,b2,b3,b4) \
(PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
#define png_IHDR PNG_CHUNK( 73, 72, 68, 82)
#define png_IDAT PNG_CHUNK( 73, 68, 65, 84)
#define png_IEND PNG_CHUNK( 73, 69, 78, 68)
#define png_PLTE PNG_CHUNK( 80, 76, 84, 69)
#define png_bKGD PNG_CHUNK( 98, 75, 71, 68)
#define png_cHRM PNG_CHUNK( 99, 72, 82, 77)
#define png_gAMA PNG_CHUNK(103, 65, 77, 65)
#define png_hIST PNG_CHUNK(104, 73, 83, 84)
#define png_iCCP PNG_CHUNK(105, 67, 67, 80)
#define png_iTXt PNG_CHUNK(105, 84, 88, 116)
#define png_oFFs PNG_CHUNK(111, 70, 70, 115)
#define png_pCAL PNG_CHUNK(112, 67, 65, 76)
#define png_sCAL PNG_CHUNK(115, 67, 65, 76)
#define png_pHYs PNG_CHUNK(112, 72, 89, 115)
#define png_sBIT PNG_CHUNK(115, 66, 73, 84)
#define png_sPLT PNG_CHUNK(115, 80, 76, 84)
#define png_sRGB PNG_CHUNK(115, 82, 71, 66)
#define png_sTER PNG_CHUNK(115, 84, 69, 82)
#define png_tEXt PNG_CHUNK(116, 69, 88, 116)
#define png_tIME PNG_CHUNK(116, 73, 77, 69)
#define png_tRNS PNG_CHUNK(116, 82, 78, 83)
#define png_zTXt PNG_CHUNK(122, 84, 88, 116)
#ifdef PNG_APNG_SUPPORTED
#define png_acTL PNG_CHUNK( 97, 99, 84, 76)
#define png_fcTL PNG_CHUNK(102, 99, 84, 76)
#define png_fdAT PNG_CHUNK(102, 100, 65, 84)
/* For png_struct.apng_flags: */
#define PNG_FIRST_FRAME_HIDDEN 0x0001
#define PNG_APNG_APP 0x0002
#endif
/* The following will work on (signed char*) strings, whereas the get_uint_32
* macro will fail on top-bit-set values because of the sign extension.
*/
#define PNG_CHUNK_FROM_STRING(s)\
PNG_CHUNK(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
/* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
* signed and the argument is a (char[]) This macro will fail miserably on
* systems where (char) is more than 8 bits.
*/
#define PNG_STRING_FROM_CHUNK(s,c)\
(void)(((char*)(s))[0]=(char)((c)>>24), ((char*)(s))[1]=(char)((c)>>16),\
((char*)(s))[2]=(char)((c)>>8), ((char*)(s))[3]=(char)((c)))
/* Do the same but terminate with a null character. */
#define PNG_CSTRING_FROM_CHUNK(s,c)\
(void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
/* Test on flag values as defined in the spec (section 5.4): */
#define PNG_CHUNK_ANCILLIARY(c) (1 & ((c) >> 29))
#define PNG_CHUNK_CRITICAL(c) (!PNG_CHUNK_ANCILLIARY(c))
#define PNG_CHUNK_PRIVATE(c) (1 & ((c) >> 21))
#define PNG_CHUNK_RESERVED(c) (1 & ((c) >> 13))
#define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >> 5))
/* Gamma values (new at libpng-1.5.4): */
#define PNG_GAMMA_MAC_OLD 151724 /* Assume '1.8' is really 2.2/1.45! */
#define PNG_GAMMA_MAC_INVERSE 65909
#define PNG_GAMMA_sRGB_INVERSE 45455
/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
/* These functions are used internally in the code. They generally
* shouldn't be used unless you are writing code to add or replace some
* functionality in libpng. More information about most functions can
* be found in the files where the functions are located.
*/
/* Check the user version string for compatibility, returns false if the version
* numbers aren't compatible.
*/
PNG_EXTERN int png_user_version_check(png_structp png_ptr,
png_const_charp user_png_ver);
/* Allocate memory for an internal libpng struct */
PNG_EXTERN PNG_FUNCTION(png_voidp,png_create_struct,PNGARG((int type)),
PNG_ALLOCATED);
/* Free memory from internal libpng struct */
PNG_EXTERN void png_destroy_struct PNGARG((png_voidp struct_ptr));
PNG_EXTERN PNG_FUNCTION(png_voidp,png_create_struct_2,
PNGARG((int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)),
PNG_ALLOCATED);
PNG_EXTERN void png_destroy_struct_2 PNGARG((png_voidp struct_ptr,
png_free_ptr free_fn, png_voidp mem_ptr));
/* Free any memory that info_ptr points to and reset struct. */
PNG_EXTERN void png_info_destroy PNGARG((png_structp png_ptr,
png_infop info_ptr));
/* Function to allocate memory for zlib. PNGAPI is disallowed. */
PNG_EXTERN PNG_FUNCTION(voidpf,png_zalloc,PNGARG((voidpf png_ptr, uInt items,
uInt size)),PNG_ALLOCATED);
/* Function to free memory for zlib. PNGAPI is disallowed. */
PNG_EXTERN void png_zfree PNGARG((voidpf png_ptr, voidpf ptr));
/* Next four functions are used internally as callbacks. PNGCBAPI is required
* but not PNG_EXPORT. PNGAPI added at libpng version 1.2.3, changed to
* PNGCBAPI at 1.5.0
*/
PNG_EXTERN void PNGCBAPI png_default_read_data PNGARG((png_structp png_ptr,
png_bytep data, png_size_t length));
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
PNG_EXTERN void PNGCBAPI png_push_fill_buffer PNGARG((png_structp png_ptr,
png_bytep buffer, png_size_t length));
#endif
PNG_EXTERN void PNGCBAPI png_default_write_data PNGARG((png_structp png_ptr,
png_bytep data, png_size_t length));
#ifdef PNG_WRITE_FLUSH_SUPPORTED
# ifdef PNG_STDIO_SUPPORTED
PNG_EXTERN void PNGCBAPI png_default_flush PNGARG((png_structp png_ptr));
# endif
#endif
/* Reset the CRC variable */
PNG_EXTERN void png_reset_crc PNGARG((png_structp png_ptr));
/* Write the "data" buffer to whatever output you are using */
PNG_EXTERN void png_write_data PNGARG((png_structp png_ptr,
png_const_bytep data, png_size_t length));
/* Read and check the PNG file signature */
PNG_EXTERN void png_read_sig PNGARG((png_structp png_ptr, png_infop info_ptr));
/* Read the chunk header (length + type name) */
PNG_EXTERN png_uint_32 png_read_chunk_header PNGARG((png_structp png_ptr));
/* Read data from whatever input you are using into the "data" buffer */
PNG_EXTERN void png_read_data PNGARG((png_structp png_ptr, png_bytep data,
png_size_t length));
/* Read bytes into buf, and update png_ptr->crc */
PNG_EXTERN void png_crc_read PNGARG((png_structp png_ptr, png_bytep buf,
png_size_t length));
/* Decompress data in a chunk that uses compression */
#if defined(PNG_READ_COMPRESSED_TEXT_SUPPORTED)
PNG_EXTERN void png_decompress_chunk PNGARG((png_structp png_ptr,
int comp_type, png_size_t chunklength, png_size_t prefix_length,
png_size_t *data_length));
#endif
/* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
PNG_EXTERN int png_crc_finish PNGARG((png_structp png_ptr, png_uint_32 skip));
/* Read the CRC from the file and compare it to the libpng calculated CRC */
PNG_EXTERN int png_crc_error PNGARG((png_structp png_ptr));
/* Calculate the CRC over a section of data. Note that we are only
* passing a maximum of 64K on systems that have this as a memory limit,
* since this is the maximum buffer size we can specify.
*/
PNG_EXTERN void png_calculate_crc PNGARG((png_structp png_ptr,
png_const_bytep ptr, png_size_t length));
#ifdef PNG_WRITE_FLUSH_SUPPORTED
PNG_EXTERN void png_flush PNGARG((png_structp png_ptr));
#endif
/* Write various chunks */
/* Write the IHDR chunk, and update the png_struct with the necessary
* information.
*/
PNG_EXTERN void png_write_IHDR PNGARG((png_structp png_ptr, png_uint_32 width,
png_uint_32 height,
int bit_depth, int color_type, int compression_method, int filter_method,
int interlace_method));
PNG_EXTERN void png_write_PLTE PNGARG((png_structp png_ptr,
png_const_colorp palette, png_uint_32 num_pal));
PNG_EXTERN void png_write_IDAT PNGARG((png_structp png_ptr, png_bytep data,
png_size_t length));
PNG_EXTERN void png_write_IEND PNGARG((png_structp png_ptr));
#ifdef PNG_WRITE_gAMA_SUPPORTED
# ifdef PNG_FLOATING_POINT_SUPPORTED
PNG_EXTERN void png_write_gAMA PNGARG((png_structp png_ptr, double file_gamma));
# endif
# ifdef PNG_FIXED_POINT_SUPPORTED
PNG_EXTERN void png_write_gAMA_fixed PNGARG((png_structp png_ptr,
png_fixed_point file_gamma));
# endif
#endif
#ifdef PNG_WRITE_sBIT_SUPPORTED
PNG_EXTERN void png_write_sBIT PNGARG((png_structp png_ptr,
png_const_color_8p sbit, int color_type));
#endif
#ifdef PNG_WRITE_cHRM_SUPPORTED
# ifdef PNG_FLOATING_POINT_SUPPORTED
PNG_EXTERN void png_write_cHRM PNGARG((png_structp png_ptr,
double white_x, double white_y,
double red_x, double red_y, double green_x, double green_y,
double blue_x, double blue_y));
# endif
PNG_EXTERN void png_write_cHRM_fixed PNGARG((png_structp png_ptr,
png_fixed_point int_white_x, png_fixed_point int_white_y,
png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
png_fixed_point int_blue_y));
#endif
#ifdef PNG_WRITE_sRGB_SUPPORTED
PNG_EXTERN void png_write_sRGB PNGARG((png_structp png_ptr,
int intent));
#endif
#ifdef PNG_WRITE_iCCP_SUPPORTED
PNG_EXTERN void png_write_iCCP PNGARG((png_structp png_ptr,
png_const_charp name, int compression_type,
png_const_charp profile, int proflen));
/* Note to maintainer: profile should be png_bytep */
#endif
#ifdef PNG_WRITE_sPLT_SUPPORTED
PNG_EXTERN void png_write_sPLT PNGARG((png_structp png_ptr,
png_const_sPLT_tp palette));
#endif
#ifdef PNG_WRITE_tRNS_SUPPORTED
PNG_EXTERN void png_write_tRNS PNGARG((png_structp png_ptr,
png_const_bytep trans, png_const_color_16p values, int number,
int color_type));
#endif
#ifdef PNG_WRITE_bKGD_SUPPORTED
PNG_EXTERN void png_write_bKGD PNGARG((png_structp png_ptr,
png_const_color_16p values, int color_type));
#endif
#ifdef PNG_WRITE_hIST_SUPPORTED
PNG_EXTERN void png_write_hIST PNGARG((png_structp png_ptr,
png_const_uint_16p hist, int num_hist));
#endif
/* Chunks that have keywords */
#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
PNG_EXTERN png_size_t png_check_keyword PNGARG((png_structp png_ptr,
png_const_charp key, png_charpp new_key));
#endif
#ifdef PNG_WRITE_tEXt_SUPPORTED
PNG_EXTERN void png_write_tEXt PNGARG((png_structp png_ptr, png_const_charp key,
png_const_charp text, png_size_t text_len));
#endif
#ifdef PNG_WRITE_zTXt_SUPPORTED
PNG_EXTERN void png_write_zTXt PNGARG((png_structp png_ptr, png_const_charp key,
png_const_charp text, png_size_t text_len, int compression));
#endif
#ifdef PNG_WRITE_iTXt_SUPPORTED
PNG_EXTERN void png_write_iTXt PNGARG((png_structp png_ptr,
int compression, png_const_charp key, png_const_charp lang,
png_const_charp lang_key, png_const_charp text));
#endif
#ifdef PNG_TEXT_SUPPORTED /* Added at version 1.0.14 and 1.2.4 */
PNG_EXTERN int png_set_text_2 PNGARG((png_structp png_ptr,
png_infop info_ptr, png_const_textp text_ptr, int num_text));
#endif
#ifdef PNG_WRITE_oFFs_SUPPORTED
PNG_EXTERN void png_write_oFFs PNGARG((png_structp png_ptr,
png_int_32 x_offset, png_int_32 y_offset, int unit_type));
#endif
#ifdef PNG_WRITE_pCAL_SUPPORTED
PNG_EXTERN void png_write_pCAL PNGARG((png_structp png_ptr, png_charp purpose,
png_int_32 X0, png_int_32 X1, int type, int nparams,
png_const_charp units, png_charpp params));
#endif
#ifdef PNG_WRITE_pHYs_SUPPORTED
PNG_EXTERN void png_write_pHYs PNGARG((png_structp png_ptr,
png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
int unit_type));
#endif
#ifdef PNG_WRITE_tIME_SUPPORTED
PNG_EXTERN void png_write_tIME PNGARG((png_structp png_ptr,
png_const_timep mod_time));
#endif
#ifdef PNG_WRITE_sCAL_SUPPORTED
PNG_EXTERN void png_write_sCAL_s PNGARG((png_structp png_ptr,
int unit, png_const_charp width, png_const_charp height));
#endif
/* Called when finished processing a row of data */
PNG_EXTERN void png_write_finish_row PNGARG((png_structp png_ptr));
/* Internal use only. Called before first row of data */
PNG_EXTERN void png_write_start_row PNGARG((png_structp png_ptr));
/* Combine a row of data, dealing with alpha, etc. if requested. 'row' is an
* array of png_ptr->width pixels. If the image is not interlaced or this
* is the final pass this just does a png_memcpy, otherwise the "display" flag
* is used to determine whether to copy pixels that are not in the current pass.
*
* Because 'png_do_read_interlace' (below) replicates pixels this allows this
* function to achieve the documented 'blocky' appearance during interlaced read
* if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
* are not changed if they are not in the current pass, when display is 0.
*
* 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
*
* The API always reads from the png_struct row buffer and always assumes that
* it is full width (png_do_read_interlace has already been called.)
*
* This function is only ever used to write to row buffers provided by the
* caller of the relevant libpng API and the row must have already been
* transformed by the read transformations.
*
* The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
* bitmasks for use within the code, otherwise runtime generated masks are used.
* The default is compile time masks.
*/
#ifndef PNG_USE_COMPILE_TIME_MASKS
# define PNG_USE_COMPILE_TIME_MASKS 1
#endif
PNG_EXTERN void png_combine_row PNGARG((png_structp png_ptr, png_bytep row,
int display));
#ifdef PNG_READ_INTERLACING_SUPPORTED
/* Expand an interlaced row: the 'row_info' describes the pass data that has
* been read in and must correspond to the pixels in 'row', the pixels are
* expanded (moved apart) in 'row' to match the final layout, when doing this
* the pixels are *replicated* to the intervening space. This is essential for
* the correct operation of png_combine_row, above.
*/
PNG_EXTERN void png_do_read_interlace PNGARG((png_row_infop row_info,
png_bytep row, int pass, png_uint_32 transformations));
#endif
/* GRR TO DO (2.0 or whenever): simplify other internal calling interfaces */