text: 
  /* pngconf.h - machine-configurable file for libpng
   *
   * libpng version 1.6.37
   *
   * Copyright (c) 2018-2019 Cosmin Truta
   * Copyright (c) 1998-2002,2004,2006-2016,2018 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
   *
   * Any machine specific code is near the front of this file, so if you
   * are configuring libpng for a machine, you may want to read the section
   * starting here down to where it starts to typedef png_color, png_text,
   * and png_info.
   */
  
  #ifndef PNGCONF_H
  #define PNGCONF_H
  
  #ifndef PNG_BUILDING_SYMBOL_TABLE /* else includes may cause problems */
  
      /* From libpng 1.6.0 libpng requires an ANSI X3.159-1989 ("ISOC90")
       * compliant C compiler for correct compilation.  The following header files
       * are required by the standard.  If your compiler doesn't provide these
       * header files, or they do not match the standard, you will need to
       * provide/improve them.
       */
      #include <limits.h>
      #include <stddef.h>
  
      /* Library header files.  These header files are all defined by ISOC90;
       * libpng expects conformant implementations, however, an ISOC90 conformant
       * system need not provide these header files if the functionality cannot be
       * implemented. In this case it will be necessary to disable the relevant
       * parts of libpng in the build of pnglibconf.h.
       *
       * Prior to 1.6.0 string.h was included here; the API changes in 1.6.0 to
       * not include this unnecessary header file.
       */
  
      #ifdef PNG_STDIO_SUPPORTED
          /* Required for the definition of FILE: */
          #include <stdio.h>
      #endif
  
      #ifdef PNG_SETJMP_SUPPORTED
          /* Required for the definition of jmp_buf and the declaration of
           * longjmp: */
          #include <setjmp.h>
      #endif
  
      #ifdef PNG_CONVERT_tIME_SUPPORTED
          /* Required for struct tm: */
          #include <time.h>
      #endif
  
  #endif /* PNG_BUILDING_SYMBOL_TABLE */
  
  /* Prior to 1.6.0, it was possible to turn off 'const' in declarations,
   * using PNG_NO_CONST.  This is no longer supported.
   */
  #define PNG_CONST const /* backward compatibility only */
  
  /* This controls optimization of the reading of 16-bit and 32-bit
   * values from PNG files.  It can be set on a per-app-file basis: it
   * just changes whether a macro is used when the function is called.
   * The library builder sets the default; if read functions are not
   * built into the library the macro implementation is forced on.
   */
  #ifndef PNG_READ_INT_FUNCTIONS_SUPPORTED
      #define PNG_USE_READ_MACROS
  #endif
  #if !defined(PNG_NO_USE_READ_MACROS) && !defined(PNG_USE_READ_MACROS)
      #if PNG_DEFAULT_READ_MACROS
          #define PNG_USE_READ_MACROS
      #endif
  #endif
  
  /* COMPILER SPECIFIC OPTIONS.
   *
   * These options are provided so that a variety of difficult compilers
   * can be used.  Some are fixed at build time (e.g. PNG_API_RULE
   * below) but still have compiler specific implementations, others
   * may be changed on a per-file basis when compiling against libpng.
   */
  
  /* The PNGARG macro was used in versions of libpng prior to 1.6.0 to protect
   * against legacy (pre ISOC90) compilers that did not understand function
   * prototypes.  It is not required for modern C compilers.
   */
  #ifndef PNGARG
      #define PNGARG(arglist) arglist
  #endif
  
  /* Function calling conventions.
   * =============================
   * Normally it is not necessary to specify to the compiler how to call
   * a function - it just does it - however on x86 systems derived from
   * Microsoft and Borland C compilers ('IBM PC', 'DOS', 'Windows' systems
   * and some others) there are multiple ways to call a function and the
   * default can be changed on the compiler command line.  For this reason
   * libpng specifies the calling convention of every exported function and
   * every function called via a user supplied function pointer.  This is
   * done in this file by defining the following macros:
   *
   * PNGAPI    Calling convention for exported functions.
   * PNGCBAPI  Calling convention for user provided (callback) functions.
   * PNGCAPI   Calling convention used by the ANSI-C library (required
   *           for longjmp callbacks and sometimes used internally to
   *           specify the calling convention for zlib).
   *
   * These macros should never be overridden.  If it is necessary to
   * change calling convention in a private build this can be done
   * by setting PNG_API_RULE (which defaults to 0) to one of the values
   * below to select the correct 'API' variants.
   *
   * PNG_API_RULE=0 Use PNGCAPI - the 'C' calling convention - throughout.
   *                This is correct in every known environment.
   * PNG_API_RULE=1 Use the operating system convention for PNGAPI and
   *                the 'C' calling convention (from PNGCAPI) for
   *                callbacks (PNGCBAPI).  This is no longer required
   *                in any known environment - if it has to be used
   *                please post an explanation of the problem to the
   *                libpng mailing list.
   *
   * These cases only differ if the operating system does not use the C
   * calling convention, at present this just means the above cases
   * (x86 DOS/Windows systems) and, even then, this does not apply to
   * Cygwin running on those systems.
   *
   * Note that the value must be defined in pnglibconf.h so that what
   * the application uses to call the library matches the conventions
   * set when building the library.
   */
  
  /* Symbol export
   * =============
   * When building a shared library it is almost always necessary to tell
   * the compiler which symbols to export.  The png.h macro 'PNG_EXPORT'
   * is used to mark the symbols.  On some systems these symbols can be
   * extracted at link time and need no special processing by the compiler,
   * on other systems the symbols are flagged by the compiler and just
   * the declaration requires a special tag applied (unfortunately) in a
   * compiler dependent way.  Some systems can do either.
   *
   * A small number of older systems also require a symbol from a DLL to
   * be flagged to the program that calls it.  This is a problem because
   * we do not know in the header file included by application code that
   * the symbol will come from a shared library, as opposed to a statically
   * linked one.  For this reason the application must tell us by setting
   * the magic flag PNG_USE_DLL to turn on the special processing before
   * it includes png.h.
   *
   * Four additional macros are used to make this happen:
   *
   * PNG_IMPEXP The magic (if any) to cause a symbol to be exported from
   *            the build or imported if PNG_USE_DLL is set - compiler
   *            and system specific.
   *
   * PNG_EXPORT_TYPE(type) A macro that pre or appends PNG_IMPEXP to
   *                       'type', compiler specific.
   *
   * PNG_DLL_EXPORT Set to the magic to use during a libpng build to
   *                make a symbol exported from the DLL.  Not used in the
   *                public header files; see pngpriv.h for how it is used
   *                in the libpng build.
   *
   * PNG_DLL_IMPORT Set to the magic to force the libpng symbols to come
   *                from a DLL - used to define PNG_IMPEXP when
   *                PNG_USE_DLL is set.
   */
  
  /* System specific discovery.
   * ==========================
   * This code is used at build time to find PNG_IMPEXP, the API settings
   * and PNG_EXPORT_TYPE(), it may also set a macro to indicate the DLL
   * import processing is possible.  On Windows systems it also sets
   * compiler-specific macros to the values required to change the calling
   * conventions of the various functions.
   */
  #if defined(_Windows) || defined(_WINDOWS) || defined(WIN32)                   \
      || defined(_WIN32) || defined(__WIN32__) || defined(__CYGWIN__)
      /* Windows system (DOS doesn't support DLLs).  Includes builds under Cygwin
       * or MinGW on any architecture currently supported by Windows.  Also
       * includes Watcom builds but these need special treatment because they are
       * not compatible with GCC or Visual C because of different calling
       * conventions.
       */
      #if PNG_API_RULE == 2
          /* If this line results in an error, either because __watcall is not
           * understood or because of a redefine just below you cannot use *this*
           * build of the library with the compiler you are using.  *This* build
           * was build using Watcom and applications must also be built using
           * Watcom!
           */
          #define PNGCAPI __watcall
      #endif
  
      #if defined(__GNUC__) || (defined(_MSC_VER) && (_MSC_VER >= 800))
          #define PNGCAPI __cdecl
          #if PNG_API_RULE == 1
              /* If this line results in an error __stdcall is not understood and
               * PNG_API_RULE should not have been set to '1'.
               */
              #define PNGAPI __stdcall
          #endif
      #else
          /* An older compiler, or one not detected (erroneously) above,
           * if necessary override on the command line to get the correct
           * variants for the compiler.
           */
          #ifndef PNGCAPI
              #define PNGCAPI _cdecl
          #endif
          #if PNG_API_RULE == 1 && !defined(PNGAPI)
              #define PNGAPI _stdcall
          #endif
      #endif /* compiler/api */
  
      /* NOTE: PNGCBAPI always defaults to PNGCAPI. */
  
      #if defined(PNGAPI) && !defined(PNG_USER_PRIVATEBUILD)
          #error "PNG_USER_PRIVATEBUILD must be defined if PNGAPI is changed"
      #endif
  
      #if (defined(_MSC_VER) && _MSC_VER < 800)                                  \
          || (defined(__BORLANDC__) && __BORLANDC__ < 0x500)
          /* older Borland and MSC
           * compilers used '__export' and required this to be after
           * the type.
           */
          #ifndef PNG_EXPORT_TYPE
              #define PNG_EXPORT_TYPE(type) type PNG_IMPEXP
          #endif
          #define PNG_DLL_EXPORT __export
      #else /* newer compiler */
          #define PNG_DLL_EXPORT __declspec(dllexport)
          #ifndef PNG_DLL_IMPORT
              #define PNG_DLL_IMPORT __declspec(dllimport)
          #endif
      #endif /* compiler */
  
  #else /* !Windows */
      #if (defined(__IBMC__) || defined(__IBMCPP__)) && defined(__OS2__)
          #define PNGAPI _System
      #else /* !Windows/x86 && !OS/2 */
          /* Use the defaults, or define PNG*API on the command line (but
           * this will have to be done for every compile!)
           */
      #endif /* other system, !OS/2 */
  #endif /* !Windows/x86 */
  
  /* Now do all the defaulting . */
  #ifndef PNGCAPI
      #define PNGCAPI
  #endif
  #ifndef PNGCBAPI
      #define PNGCBAPI PNGCAPI
  #endif
  #ifndef PNGAPI
      #define PNGAPI PNGCAPI
  #endif
  
  /* PNG_IMPEXP may be set on the compilation system command line or (if not set)
   * then in an internal header file when building the library, otherwise (when
   * using the library) it is set here.
   */
  #ifndef PNG_IMPEXP
      #if defined(PNG_USE_DLL) && defined(PNG_DLL_IMPORT)
          /* This forces use of a DLL, disallowing static linking */
          #define PNG_IMPEXP PNG_DLL_IMPORT
      #endif
  
      #ifndef PNG_IMPEXP
          #define PNG_IMPEXP
      #endif
  #endif
  
  /* In 1.5.2 the definition of PNG_FUNCTION has been changed to always treat
   * 'attributes' as a storage class - the attributes go at the start of the
   * function definition, and attributes are always appended regardless of the
   * compiler.  This considerably simplifies these macros but may cause problems
   * if any compilers both need function attributes and fail to handle them as
   * a storage class (this is unlikely.)
   */
  #ifndef PNG_FUNCTION
      #define PNG_FUNCTION(type, name, args, attributes) attributes type name args
  #endif
  
  #ifndef PNG_EXPORT_TYPE
      #define PNG_EXPORT_TYPE(type) PNG_IMPEXP type
  #endif
  
  /* The ordinal value is only relevant when preprocessing png.h for symbol
   * table entries, so we discard it here.  See the .dfn files in the
   * scripts directory.
   */
  
  #ifndef PNG_EXPORTA
      #define PNG_EXPORTA(ordinal, type, name, args, attributes)                 \
          PNG_FUNCTION(PNG_EXPORT_TYPE(type), (PNGAPI name), PNGARG(args),       \
              PNG_LINKAGE_API attributes)
  #endif
  
  /* ANSI-C (C90) does not permit a macro to be invoked with an empty argument,
   * so make something non-empty to satisfy the requirement:
   */
  #define PNG_EMPTY /*empty list*/
  
  #define PNG_EXPORT(ordinal, type, name, args)                                  \
      PNG_EXPORTA(ordinal, type, name, args, PNG_EMPTY)
  
  /* Use PNG_REMOVED to comment out a removed interface. */
  #ifndef PNG_REMOVED
      #define PNG_REMOVED(ordinal, type, name, args, attributes)
  #endif
  
  #ifndef PNG_CALLBACK
      #define PNG_CALLBACK(type, name, args) type(PNGCBAPI name) PNGARG(args)
  #endif
  
  /* Support for compiler specific function attributes.  These are used
   * so that where compiler support is available incorrect use of API
   * functions in png.h will generate compiler warnings.
   *
   * Added at libpng-1.2.41.
   */
  
  #ifndef PNG_NO_PEDANTIC_WARNINGS
      #ifndef PNG_PEDANTIC_WARNINGS_SUPPORTED
          #define PNG_PEDANTIC_WARNINGS_SUPPORTED
      #endif
  #endif
  
  #ifdef PNG_PEDANTIC_WARNINGS_SUPPORTED
      /* Support for compiler specific function attributes.  These are used
       * so that where compiler support is available, incorrect use of API
       * functions in png.h will generate compiler warnings.  Added at libpng
       * version 1.2.41.  Disabling these removes the warnings but may also
       * produce less efficient code.
       */
      #if defined(__clang__) && defined(__has_attribute)
          /* Clang defines both __clang__ and __GNUC__. Check __clang__ first. */
          #if !defined(PNG_USE_RESULT) && __has_attribute(__warn_unused_result__)
              #define PNG_USE_RESULT __attribute__((__warn_unused_result__))
          #endif
          #if !defined(PNG_NORETURN) && __has_attribute(__noreturn__)
              #define PNG_NORETURN __attribute__((__noreturn__))
          #endif
          #if !defined(PNG_ALLOCATED) && __has_attribute(__malloc__)
              #define PNG_ALLOCATED __attribute__((__malloc__))
          #endif
          #if !defined(PNG_DEPRECATED) && __has_attribute(__deprecated__)
              #define PNG_DEPRECATED __attribute__((__deprecated__))
          #endif
          #if !defined(PNG_PRIVATE)
              #ifdef __has_extension
                  #if __has_extension(attribute_unavailable_with_message)
                      #define PNG_PRIVATE                                        \
                          __attribute__((__unavailable__(                        \
                              "This function is not exported by libpng.")))
                  #endif
              #endif
          #endif
          #ifndef PNG_RESTRICT
              #define PNG_RESTRICT __restrict
          #endif
  
      #elif defined(__GNUC__)
          #ifndef PNG_USE_RESULT
              #define PNG_USE_RESULT __attribute__((__warn_unused_result__))
          #endif
          #ifndef PNG_NORETURN
              #define PNG_NORETURN __attribute__((__noreturn__))
          #endif
          #if __GNUC__ >= 3
              #ifndef PNG_ALLOCATED
                  #define PNG_ALLOCATED __attribute__((__malloc__))
              #endif
              #ifndef PNG_DEPRECATED
                  #define PNG_DEPRECATED __attribute__((__deprecated__))
              #endif
              #ifndef PNG_PRIVATE
                  #if 0 /* Doesn't work so we use deprecated instead*/
                      #define PNG_PRIVATE                                        \
                          __attribute__((warning(                                \
                              "This function is not exported by libpng.")))
                  #else
                      #define PNG_PRIVATE __attribute__((__deprecated__))
                  #endif
              #endif
              #if ((__GNUC__ > 3) || !defined(__GNUC_MINOR__)                    \
                  || (__GNUC_MINOR__ >= 1))
                  #ifndef PNG_RESTRICT
                      #define PNG_RESTRICT __restrict
                  #endif
              #endif /* __GNUC__.__GNUC_MINOR__ > 3.0 */
          #endif /* __GNUC__ >= 3 */
  
      #elif defined(_MSC_VER) && (_MSC_VER >= 1300)
          #ifndef PNG_USE_RESULT
              #define PNG_USE_RESULT /* not supported */
          #endif
          #ifndef PNG_NORETURN
              #define PNG_NORETURN __declspec(noreturn)
          #endif
          #ifndef PNG_ALLOCATED
              #if (_MSC_VER >= 1400)
                  #define PNG_ALLOCATED __declspec(restrict)
              #endif
          #endif
          #ifndef PNG_DEPRECATED
              #define PNG_DEPRECATED __declspec(deprecated)
          #endif
          #ifndef PNG_PRIVATE
              #define PNG_PRIVATE __declspec(deprecated)
          #endif
          #ifndef PNG_RESTRICT
              #if (_MSC_VER >= 1400)
                  #define PNG_RESTRICT __restrict
              #endif
          #endif
  
      #elif defined(__WATCOMC__)
          #ifndef PNG_RESTRICT
              #define PNG_RESTRICT __restrict
          #endif
      #endif
  #endif /* PNG_PEDANTIC_WARNINGS */
  
  #ifndef PNG_DEPRECATED
      #define PNG_DEPRECATED /* Use of this function is deprecated */
  #endif
  #ifndef PNG_USE_RESULT
      #define PNG_USE_RESULT /* The result of this function must be checked */
  #endif
  #ifndef PNG_NORETURN
      #define PNG_NORETURN /* This function does not return */
  #endif
  #ifndef PNG_ALLOCATED
      #define PNG_ALLOCATED /* The result of the function is new memory */
  #endif
  #ifndef PNG_PRIVATE
      #define PNG_PRIVATE /* This is a private libpng function */
  #endif
  #ifndef PNG_RESTRICT
      #define PNG_RESTRICT /* The C99 "restrict" feature */
  #endif
  
  #ifndef PNG_FP_EXPORT /* A floating point API. */
      #ifdef PNG_FLOATING_POINT_SUPPORTED
          #define PNG_FP_EXPORT(ordinal, type, name, args)                       \
              PNG_EXPORT(ordinal, type, name, args);
      #else /* No floating point APIs */
          #define PNG_FP_EXPORT(ordinal, type, name, args)
      #endif
  #endif
  #ifndef PNG_FIXED_EXPORT /* A fixed point API. */
      #ifdef PNG_FIXED_POINT_SUPPORTED
          #define PNG_FIXED_EXPORT(ordinal, type, name, args)                    \
              PNG_EXPORT(ordinal, type, name, args);
      #else /* No fixed point APIs */
          #define PNG_FIXED_EXPORT(ordinal, type, name, args)
      #endif
  #endif
  
  #ifndef PNG_BUILDING_SYMBOL_TABLE
      /* Some typedefs to get us started.  These should be safe on most of the
       * common platforms.
       *
       * png_uint_32 and png_int_32 may, currently, be larger than required to
       * hold a 32-bit value however this is not normally advisable.
       *
       * png_uint_16 and png_int_16 should always be two bytes in size - this is
       * verified at library build time.
       *
       * png_byte must always be one byte in size.
       *
       * The checks below use constants from limits.h, as defined by the ISOC90
       * standard.
       */
      #if CHAR_BIT == 8 && UCHAR_MAX == 255
  typedef unsigned char png_byte;
      #else
          #error "libpng requires 8-bit bytes"
      #endif
  
      #if INT_MIN == -32768 && INT_MAX == 32767
  typedef int png_int_16;
      #elif SHRT_MIN == -32768 && SHRT_MAX == 32767
  typedef short png_int_16;
      #else
          #error "libpng requires a signed 16-bit type"
      #endif
  
      #if UINT_MAX == 65535
  typedef unsigned int png_uint_16;
      #elif USHRT_MAX == 65535
  typedef unsigned short png_uint_16;
      #else
          #error "libpng requires an unsigned 16-bit type"
      #endif
  
      #if INT_MIN < -2147483646 && INT_MAX > 2147483646
  typedef int png_int_32;
      #elif LONG_MIN < -2147483646 && LONG_MAX > 2147483646
  typedef long int png_int_32;
      #else
          #error "libpng requires a signed 32-bit (or more) type"
      #endif
  
      #if UINT_MAX > 4294967294U
  typedef unsigned int png_uint_32;
      #elif ULONG_MAX > 4294967294U
  typedef unsigned long int png_uint_32;
      #else
          #error "libpng requires an unsigned 32-bit (or more) type"
      #endif
  
  /* Prior to 1.6.0, it was possible to disable the use of size_t and ptrdiff_t.
   * From 1.6.0 onwards, an ISO C90 compiler, as well as a standard-compliant
   * behavior of sizeof and ptrdiff_t are required.
   * The legacy typedefs are provided here for backwards compatibility.
   */
  typedef size_t png_size_t;
  typedef ptrdiff_t png_ptrdiff_t;
  
      /* libpng needs to know the maximum value of 'size_t' and this controls the
       * definition of png_alloc_size_t, below.  This maximum value of size_t
       * limits but does not control the maximum allocations the library makes -
       * there is direct application control of this through
       * png_set_user_limits().
       */
      #ifndef PNG_SMALL_SIZE_T
          /* Compiler specific tests for systems where size_t is known to be less
           * than 32 bits (some of these systems may no longer work because of the
           * lack of 'far' support; see above.)
           */
          #if (defined(__TURBOC__) && !defined(__FLAT__))                        \
              || (defined(_MSC_VER) && defined(MAXSEG_64K))
              #define PNG_SMALL_SIZE_T
          #endif
      #endif
  
      /* png_alloc_size_t is guaranteed to be no smaller than size_t, and no
       * smaller than png_uint_32.  Casts from size_t or png_uint_32 to
       * png_alloc_size_t are not necessary; in fact, it is recommended not to use
       * them at all, so that the compiler can complain when something turns out
       * to be problematic.
       *
       * Casts in the other direction (from png_alloc_size_t to size_t or
       * png_uint_32) should be explicitly applied; however, we do not expect to
       * encounter practical situations that require such conversions.
       *
       * PNG_SMALL_SIZE_T must be defined if the maximum value of size_t is less
       * than 4294967295 - i.e. less than the maximum value of png_uint_32.
       */
      #ifdef PNG_SMALL_SIZE_T
  typedef png_uint_32 png_alloc_size_t;
      #else
  typedef size_t png_alloc_size_t;
      #endif
  
  /* Prior to 1.6.0 libpng offered limited support for Microsoft C compiler
   * implementations of Intel CPU specific support of user-mode segmented address
   * spaces, where 16-bit pointers address more than 65536 bytes of memory using
   * separate 'segment' registers.  The implementation requires two different
   * types of pointer (only one of which includes the segment value.)
   *
   * If required this support is available in version 1.2 of libpng and may be
   * available in versions through 1.5, although the correctness of the code has
   * not been verified recently.
   */
  
  /* Typedef for floating-point numbers that are converted to fixed-point with a
   * multiple of 100,000, e.g., gamma
   */
  typedef png_int_32 png_fixed_point;
  
  /* Add typedefs for pointers */
  typedef void* png_voidp;
  typedef const void* png_const_voidp;
  typedef png_byte* png_bytep;
  typedef const png_byte* png_const_bytep;
  typedef png_uint_32* png_uint_32p;
  typedef const png_uint_32* png_const_uint_32p;
  typedef png_int_32* png_int_32p;
  typedef const png_int_32* png_const_int_32p;
  typedef png_uint_16* png_uint_16p;
  typedef const png_uint_16* png_const_uint_16p;
  typedef png_int_16* png_int_16p;
  typedef const png_int_16* png_const_int_16p;
  typedef char* png_charp;
  typedef const char* png_const_charp;
  typedef png_fixed_point* png_fixed_point_p;
  typedef const png_fixed_point* png_const_fixed_point_p;
  typedef size_t* png_size_tp;
  typedef const size_t* png_const_size_tp;
  
      #ifdef PNG_STDIO_SUPPORTED
  typedef FILE* png_FILE_p;
      #endif
  
      #ifdef PNG_FLOATING_POINT_SUPPORTED
  typedef double* png_doublep;
  typedef const double* png_const_doublep;
      #endif
  
  /* Pointers to pointers; i.e. arrays */
  typedef png_byte** png_bytepp;
  typedef png_uint_32** png_uint_32pp;
  typedef png_int_32** png_int_32pp;
  typedef png_uint_16** png_uint_16pp;
  typedef png_int_16** png_int_16pp;
  typedef const char** png_const_charpp;
  typedef char** png_charpp;
  typedef png_fixed_point** png_fixed_point_pp;
      #ifdef PNG_FLOATING_POINT_SUPPORTED
  typedef double** png_doublepp;
      #endif
  
  /* Pointers to pointers to pointers; i.e., pointer to array */
  typedef char*** png_charppp;
  
  #endif /* PNG_BUILDING_SYMBOL_TABLE */
  
  #endif /* PNGCONF_H */
  