2 /* pngconf.h - machine-configurable file for libpng
4 * libpng version 1.6.43
6 * Copyright (c) 2018-2024 Cosmin Truta
7 * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson
8 * Copyright (c) 1996-1997 Andreas Dilger
9 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
11 * This code is released under the libpng license.
12 * For conditions of distribution and use, see the disclaimer
13 * and license in png.h
15 * Any machine specific code is near the front of this file, so if you
16 * are configuring libpng for a machine, you may want to read the section
17 * starting here down to where it starts to typedef png_color, png_text,
24 #ifndef PNG_BUILDING_SYMBOL_TABLE /* else includes may cause problems */
26 /* From libpng 1.6.0 libpng requires an ANSI X3.159-1989 ("ISOC90") compliant C
27 * compiler for correct compilation. The following header files are required by
28 * the standard. If your compiler doesn't provide these header files, or they
29 * do not match the standard, you will need to provide/improve them.
34 /* Library header files. These header files are all defined by ISOC90; libpng
35 * expects conformant implementations, however, an ISOC90 conformant system need
36 * not provide these header files if the functionality cannot be implemented.
37 * In this case it will be necessary to disable the relevant parts of libpng in
38 * the build of pnglibconf.h.
40 * Prior to 1.6.0 string.h was included here; the API changes in 1.6.0 to not
41 * include this unnecessary header file.
44 #ifdef PNG_STDIO_SUPPORTED
45 /* Required for the definition of FILE: */
49 #ifdef PNG_SETJMP_SUPPORTED
50 /* Required for the definition of jmp_buf and the declaration of longjmp: */
54 #ifdef PNG_CONVERT_tIME_SUPPORTED
55 /* Required for struct tm: */
59 #endif /* PNG_BUILDING_SYMBOL_TABLE */
61 /* Prior to 1.6.0, it was possible to turn off 'const' in declarations,
62 * using PNG_NO_CONST. This is no longer supported.
64 #define PNG_CONST const /* backward compatibility only */
66 /* This controls optimization of the reading of 16-bit and 32-bit
67 * values from PNG files. It can be set on a per-app-file basis: it
68 * just changes whether a macro is used when the function is called.
69 * The library builder sets the default; if read functions are not
70 * built into the library the macro implementation is forced on.
72 #ifndef PNG_READ_INT_FUNCTIONS_SUPPORTED
73 # define PNG_USE_READ_MACROS
75 #if !defined(PNG_NO_USE_READ_MACROS) && !defined(PNG_USE_READ_MACROS)
76 # if PNG_DEFAULT_READ_MACROS
77 # define PNG_USE_READ_MACROS
81 /* COMPILER SPECIFIC OPTIONS.
83 * These options are provided so that a variety of difficult compilers
84 * can be used. Some are fixed at build time (e.g. PNG_API_RULE
85 * below) but still have compiler specific implementations, others
86 * may be changed on a per-file basis when compiling against libpng.
89 /* The PNGARG macro was used in versions of libpng prior to 1.6.0 to protect
90 * against legacy (pre ISOC90) compilers that did not understand function
91 * prototypes. It is not required for modern C compilers.
94 # define PNGARG(arglist) arglist
97 /* Function calling conventions.
98 * =============================
99 * Normally it is not necessary to specify to the compiler how to call
100 * a function - it just does it - however on x86 systems derived from
101 * Microsoft and Borland C compilers ('IBM PC', 'DOS', 'Windows' systems
102 * and some others) there are multiple ways to call a function and the
103 * default can be changed on the compiler command line. For this reason
104 * libpng specifies the calling convention of every exported function and
105 * every function called via a user supplied function pointer. This is
106 * done in this file by defining the following macros:
108 * PNGAPI Calling convention for exported functions.
109 * PNGCBAPI Calling convention for user provided (callback) functions.
110 * PNGCAPI Calling convention used by the ANSI-C library (required
111 * for longjmp callbacks and sometimes used internally to
112 * specify the calling convention for zlib).
114 * These macros should never be overridden. If it is necessary to
115 * change calling convention in a private build this can be done
116 * by setting PNG_API_RULE (which defaults to 0) to one of the values
117 * below to select the correct 'API' variants.
119 * PNG_API_RULE=0 Use PNGCAPI - the 'C' calling convention - throughout.
120 * This is correct in every known environment.
121 * PNG_API_RULE=1 Use the operating system convention for PNGAPI and
122 * the 'C' calling convention (from PNGCAPI) for
123 * callbacks (PNGCBAPI). This is no longer required
124 * in any known environment - if it has to be used
125 * please post an explanation of the problem to the
126 * libpng mailing list.
128 * These cases only differ if the operating system does not use the C
129 * calling convention, at present this just means the above cases
130 * (x86 DOS/Windows systems) and, even then, this does not apply to
131 * Cygwin running on those systems.
133 * Note that the value must be defined in pnglibconf.h so that what
134 * the application uses to call the library matches the conventions
135 * set when building the library.
140 * When building a shared library it is almost always necessary to tell
141 * the compiler which symbols to export. The png.h macro 'PNG_EXPORT'
142 * is used to mark the symbols. On some systems these symbols can be
143 * extracted at link time and need no special processing by the compiler,
144 * on other systems the symbols are flagged by the compiler and just
145 * the declaration requires a special tag applied (unfortunately) in a
146 * compiler dependent way. Some systems can do either.
148 * A small number of older systems also require a symbol from a DLL to
149 * be flagged to the program that calls it. This is a problem because
150 * we do not know in the header file included by application code that
151 * the symbol will come from a shared library, as opposed to a statically
152 * linked one. For this reason the application must tell us by setting
153 * the magic flag PNG_USE_DLL to turn on the special processing before
156 * Four additional macros are used to make this happen:
158 * PNG_IMPEXP The magic (if any) to cause a symbol to be exported from
159 * the build or imported if PNG_USE_DLL is set - compiler
160 * and system specific.
162 * PNG_EXPORT_TYPE(type) A macro that pre or appends PNG_IMPEXP to
163 * 'type', compiler specific.
165 * PNG_DLL_EXPORT Set to the magic to use during a libpng build to
166 * make a symbol exported from the DLL. Not used in the
167 * public header files; see pngpriv.h for how it is used
168 * in the libpng build.
170 * PNG_DLL_IMPORT Set to the magic to force the libpng symbols to come
171 * from a DLL - used to define PNG_IMPEXP when
172 * PNG_USE_DLL is set.
175 /* System specific discovery.
176 * ==========================
177 * This code is used at build time to find PNG_IMPEXP, the API settings
178 * and PNG_EXPORT_TYPE(), it may also set a macro to indicate the DLL
179 * import processing is possible. On Windows systems it also sets
180 * compiler-specific macros to the values required to change the calling
181 * conventions of the various functions.
183 #if defined(_WIN32) || defined(__WIN32__) || defined(__NT__) || \
185 /* Windows system (DOS doesn't support DLLs). Includes builds under Cygwin or
186 * MinGW on any architecture currently supported by Windows. Also includes
187 * Watcom builds but these need special treatment because they are not
188 * compatible with GCC or Visual C because of different calling conventions.
190 # if PNG_API_RULE == 2
191 /* If this line results in an error, either because __watcall is not
192 * understood or because of a redefine just below you cannot use *this*
193 * build of the library with the compiler you are using. *This* build was
194 * build using Watcom and applications must also be built using Watcom!
196 # define PNGCAPI __watcall
199 # if defined(__GNUC__) || (defined(_MSC_VER) && (_MSC_VER >= 800))
200 # define PNGCAPI __cdecl
201 # if PNG_API_RULE == 1
202 /* If this line results in an error __stdcall is not understood and
203 * PNG_API_RULE should not have been set to '1'.
205 # define PNGAPI __stdcall
208 /* An older compiler, or one not detected (erroneously) above,
209 * if necessary override on the command line to get the correct
210 * variants for the compiler.
213 # define PNGCAPI _cdecl
215 # if PNG_API_RULE == 1 && !defined(PNGAPI)
216 # define PNGAPI _stdcall
218 # endif /* compiler/api */
220 /* NOTE: PNGCBAPI always defaults to PNGCAPI. */
222 # if defined(PNGAPI) && !defined(PNG_USER_PRIVATEBUILD)
223 # error "PNG_USER_PRIVATEBUILD must be defined if PNGAPI is changed"
226 # if (defined(_MSC_VER) && _MSC_VER < 800) ||\
227 (defined(__BORLANDC__) && __BORLANDC__ < 0x500)
228 /* older Borland and MSC
229 * compilers used '__export' and required this to be after
232 # ifndef PNG_EXPORT_TYPE
233 # define PNG_EXPORT_TYPE(type) type PNG_IMPEXP
235 # define PNG_DLL_EXPORT __export
236 # else /* newer compiler */
237 # define PNG_DLL_EXPORT __declspec(dllexport)
238 # ifndef PNG_DLL_IMPORT
239 # define PNG_DLL_IMPORT __declspec(dllimport)
241 # endif /* compiler */
244 # if (defined(__IBMC__) || defined(__IBMCPP__)) && defined(__OS2__)
245 # define PNGAPI _System
246 # else /* !Windows/x86 && !OS/2 */
247 /* Use the defaults, or define PNG*API on the command line (but
248 * this will have to be done for every compile!)
250 # endif /* other system, !OS/2 */
251 #endif /* !Windows/x86 */
253 /* Now do all the defaulting . */
258 # define PNGCBAPI PNGCAPI
261 # define PNGAPI PNGCAPI
264 /* PNG_IMPEXP may be set on the compilation system command line or (if not set)
265 * then in an internal header file when building the library, otherwise (when
266 * using the library) it is set here.
269 # if defined(PNG_USE_DLL) && defined(PNG_DLL_IMPORT)
270 /* This forces use of a DLL, disallowing static linking */
271 # define PNG_IMPEXP PNG_DLL_IMPORT
279 /* In 1.5.2 the definition of PNG_FUNCTION has been changed to always treat
280 * 'attributes' as a storage class - the attributes go at the start of the
281 * function definition, and attributes are always appended regardless of the
282 * compiler. This considerably simplifies these macros but may cause problems
283 * if any compilers both need function attributes and fail to handle them as
284 * a storage class (this is unlikely.)
287 # define PNG_FUNCTION(type, name, args, attributes) attributes type name args
290 #ifndef PNG_EXPORT_TYPE
291 # define PNG_EXPORT_TYPE(type) PNG_IMPEXP type
294 /* The ordinal value is only relevant when preprocessing png.h for symbol
295 * table entries, so we discard it here. See the .dfn files in the
300 # define PNG_EXPORTA(ordinal, type, name, args, attributes) \
301 PNG_FUNCTION(PNG_EXPORT_TYPE(type), (PNGAPI name), PNGARG(args), \
302 PNG_LINKAGE_API attributes)
305 /* ANSI-C (C90) does not permit a macro to be invoked with an empty argument,
306 * so make something non-empty to satisfy the requirement:
308 #define PNG_EMPTY /*empty list*/
310 #define PNG_EXPORT(ordinal, type, name, args) \
311 PNG_EXPORTA(ordinal, type, name, args, PNG_EMPTY)
313 /* Use PNG_REMOVED to comment out a removed interface. */
315 # define PNG_REMOVED(ordinal, type, name, args, attributes)
319 # define PNG_CALLBACK(type, name, args) type (PNGCBAPI name) PNGARG(args)
322 /* Support for compiler specific function attributes. These are used
323 * so that where compiler support is available incorrect use of API
324 * functions in png.h will generate compiler warnings.
326 * Added at libpng-1.2.41.
329 #ifndef PNG_NO_PEDANTIC_WARNINGS
330 # ifndef PNG_PEDANTIC_WARNINGS_SUPPORTED
331 # define PNG_PEDANTIC_WARNINGS_SUPPORTED
335 #ifdef PNG_PEDANTIC_WARNINGS_SUPPORTED
336 /* Support for compiler specific function attributes. These are used
337 * so that where compiler support is available, incorrect use of API
338 * functions in png.h will generate compiler warnings. Added at libpng
339 * version 1.2.41. Disabling these removes the warnings but may also produce
340 * less efficient code.
342 # if defined(__clang__) && defined(__has_attribute)
343 /* Clang defines both __clang__ and __GNUC__. Check __clang__ first. */
344 # if !defined(PNG_USE_RESULT) && __has_attribute(__warn_unused_result__)
345 # define PNG_USE_RESULT __attribute__((__warn_unused_result__))
347 # if !defined(PNG_NORETURN) && __has_attribute(__noreturn__)
348 # define PNG_NORETURN __attribute__((__noreturn__))
350 # if !defined(PNG_ALLOCATED) && __has_attribute(__malloc__)
351 # define PNG_ALLOCATED __attribute__((__malloc__))
353 # if !defined(PNG_DEPRECATED) && __has_attribute(__deprecated__)
354 # define PNG_DEPRECATED __attribute__((__deprecated__))
356 # if !defined(PNG_PRIVATE)
357 # ifdef __has_extension
358 # if __has_extension(attribute_unavailable_with_message)
359 # define PNG_PRIVATE __attribute__((__unavailable__(\
360 "This function is not exported by libpng.")))
364 # ifndef PNG_RESTRICT
365 # define PNG_RESTRICT __restrict
368 # elif defined(__GNUC__)
369 # ifndef PNG_USE_RESULT
370 # define PNG_USE_RESULT __attribute__((__warn_unused_result__))
372 # ifndef PNG_NORETURN
373 # define PNG_NORETURN __attribute__((__noreturn__))
376 # ifndef PNG_ALLOCATED
377 # define PNG_ALLOCATED __attribute__((__malloc__))
379 # ifndef PNG_DEPRECATED
380 # define PNG_DEPRECATED __attribute__((__deprecated__))
383 # if 0 /* Doesn't work so we use deprecated instead*/
384 # define PNG_PRIVATE \
385 __attribute__((warning("This function is not exported by libpng.")))
387 # define PNG_PRIVATE \
388 __attribute__((__deprecated__))
391 # if ((__GNUC__ > 3) || !defined(__GNUC_MINOR__) || (__GNUC_MINOR__ >= 1))
392 # ifndef PNG_RESTRICT
393 # define PNG_RESTRICT __restrict
395 # endif /* __GNUC__.__GNUC_MINOR__ > 3.0 */
396 # endif /* __GNUC__ >= 3 */
398 # elif defined(_MSC_VER) && (_MSC_VER >= 1300)
399 # ifndef PNG_USE_RESULT
400 # define PNG_USE_RESULT /* not supported */
402 # ifndef PNG_NORETURN
403 # define PNG_NORETURN __declspec(noreturn)
405 # ifndef PNG_ALLOCATED
406 # if (_MSC_VER >= 1400)
407 # define PNG_ALLOCATED __declspec(restrict)
410 # ifndef PNG_DEPRECATED
411 # define PNG_DEPRECATED __declspec(deprecated)
414 # define PNG_PRIVATE __declspec(deprecated)
416 # ifndef PNG_RESTRICT
417 # if (_MSC_VER >= 1400)
418 # define PNG_RESTRICT __restrict
422 # elif defined(__WATCOMC__)
423 # ifndef PNG_RESTRICT
424 # define PNG_RESTRICT __restrict
427 #endif /* PNG_PEDANTIC_WARNINGS */
429 #ifndef PNG_DEPRECATED
430 # define PNG_DEPRECATED /* Use of this function is deprecated */
432 #ifndef PNG_USE_RESULT
433 # define PNG_USE_RESULT /* The result of this function must be checked */
436 # define PNG_NORETURN /* This function does not return */
438 #ifndef PNG_ALLOCATED
439 # define PNG_ALLOCATED /* The result of the function is new memory */
442 # define PNG_PRIVATE /* This is a private libpng function */
445 # define PNG_RESTRICT /* The C99 "restrict" feature */
448 #ifndef PNG_FP_EXPORT /* A floating point API. */
449 # ifdef PNG_FLOATING_POINT_SUPPORTED
450 # define PNG_FP_EXPORT(ordinal, type, name, args)\
451 PNG_EXPORT(ordinal, type, name, args);
452 # else /* No floating point APIs */
453 # define PNG_FP_EXPORT(ordinal, type, name, args)
456 #ifndef PNG_FIXED_EXPORT /* A fixed point API. */
457 # ifdef PNG_FIXED_POINT_SUPPORTED
458 # define PNG_FIXED_EXPORT(ordinal, type, name, args)\
459 PNG_EXPORT(ordinal, type, name, args);
460 # else /* No fixed point APIs */
461 # define PNG_FIXED_EXPORT(ordinal, type, name, args)
465 #ifndef PNG_BUILDING_SYMBOL_TABLE
466 /* Some typedefs to get us started. These should be safe on most of the common
469 * png_uint_32 and png_int_32 may, currently, be larger than required to hold a
470 * 32-bit value however this is not normally advisable.
472 * png_uint_16 and png_int_16 should always be two bytes in size - this is
473 * verified at library build time.
475 * png_byte must always be one byte in size.
477 * The checks below use constants from limits.h, as defined by the ISOC90
480 #if CHAR_BIT == 8 && UCHAR_MAX == 255
481 typedef unsigned char png_byte
;
483 # error "libpng requires 8-bit bytes"
486 #if INT_MIN == -32768 && INT_MAX == 32767
487 typedef int png_int_16
;
488 #elif SHRT_MIN == -32768 && SHRT_MAX == 32767
489 typedef short png_int_16
;
491 # error "libpng requires a signed 16-bit type"
494 #if UINT_MAX == 65535
495 typedef unsigned int png_uint_16
;
496 #elif USHRT_MAX == 65535
497 typedef unsigned short png_uint_16
;
499 # error "libpng requires an unsigned 16-bit type"
502 #if INT_MIN < -2147483646 && INT_MAX > 2147483646
503 typedef int png_int_32
;
504 #elif LONG_MIN < -2147483646 && LONG_MAX > 2147483646
505 typedef long int png_int_32
;
507 # error "libpng requires a signed 32-bit (or more) type"
510 #if UINT_MAX > 4294967294U
511 typedef unsigned int png_uint_32
;
512 #elif ULONG_MAX > 4294967294U
513 typedef unsigned long int png_uint_32
;
515 # error "libpng requires an unsigned 32-bit (or more) type"
518 /* Prior to 1.6.0, it was possible to disable the use of size_t and ptrdiff_t.
519 * From 1.6.0 onwards, an ISO C90 compiler, as well as a standard-compliant
520 * behavior of sizeof and ptrdiff_t are required.
521 * The legacy typedefs are provided here for backwards compatibility.
523 typedef size_t png_size_t
;
524 typedef ptrdiff_t png_ptrdiff_t
;
526 /* libpng needs to know the maximum value of 'size_t' and this controls the
527 * definition of png_alloc_size_t, below. This maximum value of size_t limits
528 * but does not control the maximum allocations the library makes - there is
529 * direct application control of this through png_set_user_limits().
531 #ifndef PNG_SMALL_SIZE_T
532 /* Compiler specific tests for systems where size_t is known to be less than
533 * 32 bits (some of these systems may no longer work because of the lack of
534 * 'far' support; see above.)
536 # if (defined(__TURBOC__) && !defined(__FLAT__)) ||\
537 (defined(_MSC_VER) && defined(MAXSEG_64K))
538 # define PNG_SMALL_SIZE_T
542 /* png_alloc_size_t is guaranteed to be no smaller than size_t, and no smaller
543 * than png_uint_32. Casts from size_t or png_uint_32 to png_alloc_size_t are
544 * not necessary; in fact, it is recommended not to use them at all, so that
545 * the compiler can complain when something turns out to be problematic.
547 * Casts in the other direction (from png_alloc_size_t to size_t or
548 * png_uint_32) should be explicitly applied; however, we do not expect to
549 * encounter practical situations that require such conversions.
551 * PNG_SMALL_SIZE_T must be defined if the maximum value of size_t is less than
552 * 4294967295 - i.e. less than the maximum value of png_uint_32.
554 #ifdef PNG_SMALL_SIZE_T
555 typedef png_uint_32 png_alloc_size_t
;
557 typedef size_t png_alloc_size_t
;
560 /* Prior to 1.6.0 libpng offered limited support for Microsoft C compiler
561 * implementations of Intel CPU specific support of user-mode segmented address
562 * spaces, where 16-bit pointers address more than 65536 bytes of memory using
563 * separate 'segment' registers. The implementation requires two different
564 * types of pointer (only one of which includes the segment value.)
566 * If required this support is available in version 1.2 of libpng and may be
567 * available in versions through 1.5, although the correctness of the code has
568 * not been verified recently.
571 /* Typedef for floating-point numbers that are converted to fixed-point with a
572 * multiple of 100,000, e.g., gamma
574 typedef png_int_32 png_fixed_point
;
576 /* Add typedefs for pointers */
577 typedef void * png_voidp
;
578 typedef const void * png_const_voidp
;
579 typedef png_byte
* png_bytep
;
580 typedef const png_byte
* png_const_bytep
;
581 typedef png_uint_32
* png_uint_32p
;
582 typedef const png_uint_32
* png_const_uint_32p
;
583 typedef png_int_32
* png_int_32p
;
584 typedef const png_int_32
* png_const_int_32p
;
585 typedef png_uint_16
* png_uint_16p
;
586 typedef const png_uint_16
* png_const_uint_16p
;
587 typedef png_int_16
* png_int_16p
;
588 typedef const png_int_16
* png_const_int_16p
;
589 typedef char * png_charp
;
590 typedef const char * png_const_charp
;
591 typedef png_fixed_point
* png_fixed_point_p
;
592 typedef const png_fixed_point
* png_const_fixed_point_p
;
593 typedef size_t * png_size_tp
;
594 typedef const size_t * png_const_size_tp
;
596 #ifdef PNG_STDIO_SUPPORTED
597 typedef FILE * png_FILE_p
;
600 #ifdef PNG_FLOATING_POINT_SUPPORTED
601 typedef double * png_doublep
;
602 typedef const double * png_const_doublep
;
605 /* Pointers to pointers; i.e. arrays */
606 typedef png_byte
* * png_bytepp
;
607 typedef png_uint_32
* * png_uint_32pp
;
608 typedef png_int_32
* * png_int_32pp
;
609 typedef png_uint_16
* * png_uint_16pp
;
610 typedef png_int_16
* * png_int_16pp
;
611 typedef const char * * png_const_charpp
;
612 typedef char * * png_charpp
;
613 typedef png_fixed_point
* * png_fixed_point_pp
;
614 #ifdef PNG_FLOATING_POINT_SUPPORTED
615 typedef double * * png_doublepp
;
618 /* Pointers to pointers to pointers; i.e., pointer to array */
619 typedef char * * * png_charppp
;
621 #endif /* PNG_BUILDING_SYMBOL_TABLE */
623 #endif /* PNGCONF_H */