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ext/zstd/contrib/seekable_format/zstdseek_decompress.c  view on Meta::CPAN

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 * All rights reserved.
 *
 * This source code is licensed under both the BSD-style license (found in the
 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
 * in the COPYING file in the root directory of this source tree).
 * You may select, at your option, one of the above-listed licenses.
 */

/* *********************************************************
*  Turn on Large Files support (>4GB) for 32-bit Linux/Unix
***********************************************************/
#if !defined(__64BIT__) || defined(__MINGW32__)       /* No point defining Large file for 64 bit but MinGW-w64 requires it */
#  if !defined(_FILE_OFFSET_BITS)
#    define _FILE_OFFSET_BITS 64                      /* turn off_t into a 64-bit type for ftello, fseeko */
#  endif
#  if !defined(_LARGEFILE_SOURCE)                     /* obsolete macro, replaced with _FILE_OFFSET_BITS */
#    define _LARGEFILE_SOURCE 1                       /* Large File Support extension (LFS) - fseeko, ftello */
#  endif
#  if defined(_AIX) || defined(__hpux)
#    define _LARGE_FILES                              /* Large file support on 32-bits AIX and HP-UX */
#  endif
#endif

/* ************************************************************
*  Detect POSIX version
*  PLATFORM_POSIX_VERSION = 0 for non-Unix e.g. Windows
*  PLATFORM_POSIX_VERSION = 1 for Unix-like but non-POSIX
*  PLATFORM_POSIX_VERSION > 1 is equal to found _POSIX_VERSION
*  Value of PLATFORM_POSIX_VERSION can be forced on command line
***************************************************************/
#ifndef PLATFORM_POSIX_VERSION

#  if (defined(__APPLE__) && defined(__MACH__)) || defined(__SVR4) || defined(_AIX) || defined(__hpux) /* POSIX.1-2001 (SUSv3) conformant */ \
     || defined(__DragonFly__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__)  /* BSD distros */
     /* exception rule : force posix version to 200112L,
      * note: it's better to use unistd.h's _POSIX_VERSION whenever possible */
#    define PLATFORM_POSIX_VERSION 200112L

/* try to determine posix version through official unistd.h's _POSIX_VERSION (https://pubs.opengroup.org/onlinepubs/7908799/xsh/unistd.h.html).
 * note : there is no simple way to know in advance if <unistd.h> is present or not on target system,
 * Posix specification mandates its presence and its content, but target system must respect this spec.
 * It's necessary to _not_ #include <unistd.h> whenever target OS is not unix-like
 * otherwise it will block preprocessing stage.
 * The following list of build macros tries to "guess" if target OS is likely unix-like, and therefore can #include <unistd.h>
 */
#  elif !defined(_WIN32) \
     && ( defined(__unix__) || defined(__unix) \
       || defined(__midipix__) || defined(__VMS) || defined(__HAIKU__) )

#    if defined(__linux__) || defined(__linux) || defined(__CYGWIN__)
#      ifndef _POSIX_C_SOURCE
#        define _POSIX_C_SOURCE 200809L  /* feature test macro : https://www.gnu.org/software/libc/manual/html_node/Feature-Test-Macros.html */
#      endif
#    endif
#    include <unistd.h>  /* declares _POSIX_VERSION */
#    if defined(_POSIX_VERSION)  /* POSIX compliant */
#      define PLATFORM_POSIX_VERSION _POSIX_VERSION
#    else
#      define PLATFORM_POSIX_VERSION 1
#    endif

#    ifdef __UCLIBC__
#     ifndef __USE_MISC
#      define __USE_MISC /* enable st_mtim on uclibc */
#     endif
#    endif

#  else  /* non-unix target platform (like Windows) */
#    define PLATFORM_POSIX_VERSION 0
#  endif

#endif   /* PLATFORM_POSIX_VERSION */


/* ************************************************************
* Avoid fseek()'s 2GiB barrier with MSVC, macOS, *BSD, MinGW
***************************************************************/
#if defined(_MSC_VER) && _MSC_VER >= 1400
#   define LONG_SEEK _fseeki64
#elif !defined(__64BIT__) && (PLATFORM_POSIX_VERSION >= 200112L) /* No point defining Large file for 64 bit */
#   define LONG_SEEK fseeko
#elif defined(__MINGW32__) && !defined(__STRICT_ANSI__) && !defined(__NO_MINGW_LFS) && defined(__MSVCRT__)
#   define LONG_SEEK fseeko64
#elif defined(_WIN32) && !defined(__DJGPP__)
#   include <windows.h>
    static int LONG_SEEK(FILE* file, __int64 offset, int origin) {
        LARGE_INTEGER off;
        DWORD method;
        off.QuadPart = offset;
        if (origin == SEEK_END)
            method = FILE_END;
        else if (origin == SEEK_CUR)
            method = FILE_CURRENT;
        else
            method = FILE_BEGIN;

        if (SetFilePointerEx((HANDLE) _get_osfhandle(_fileno(file)), off, NULL, method))
            return 0;
        else
            return -1;
    }
#else
#   define LONG_SEEK fseek
#endif

#include <stdlib.h>  /* malloc, free */
#include <stdio.h>   /* FILE* */
#include <limits.h>  /* UNIT_MAX */
#include <assert.h>

#define XXH_STATIC_LINKING_ONLY
#include "xxhash.h"