src/zlib-ng/zbuild.h

#ifndef _ZBUILD_H
#define _ZBUILD_H

#define _POSIX_SOURCE 1  /* fileno */
#ifndef _POSIX_C_SOURCE
#  define _POSIX_C_SOURCE 200112L /* snprintf, posix_memalign */
#endif

#include <stddef.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>

/* Determine compiler version of C Standard */
#ifdef __STDC_VERSION__
#  if __STDC_VERSION__ >= 199901L
#    ifndef STDC99
#      define STDC99
#    endif
#  endif
#  if __STDC_VERSION__ >= 201112L
#    ifndef STDC11
#      define STDC11
#    endif
#  endif
#endif

/* Determine compiler support for TLS */
#ifndef Z_TLS
#  if defined(STDC11) && !defined(__STDC_NO_THREADS__)
#    define Z_TLS _Thread_local
#  elif defined(__GNUC__) || defined(__SUNPRO_C)
#    define Z_TLS __thread
#  elif defined(_WIN32) && (defined(_MSC_VER) || defined(__ICL))
#    define Z_TLS __declspec(thread)
#  else
#    warning Unable to detect Thread Local Storage support.
#    define Z_TLS
#  endif
#endif

/* This has to be first include that defines any types */
#if defined(_MSC_VER)
#  if defined(_WIN64)
    typedef __int64 ssize_t;
#  else
    typedef long ssize_t;
#  endif
#endif

/* MS Visual Studio does not allow inline in C, only C++.
   But it provides __inline instead, so use that. */
#if defined(_MSC_VER) && !defined(inline) && !defined(__cplusplus)
#  define inline __inline
#endif

#if defined(ZLIB_COMPAT)
#  define PREFIX(x) x
#  define PREFIX2(x) ZLIB_ ## x
#  define PREFIX3(x) z_ ## x
#  define PREFIX4(x) x ## 64
#  define zVersion zlibVersion
#  define z_size_t unsigned long
#else
#  define PREFIX(x) zng_ ## x
#  define PREFIX2(x) ZLIBNG_ ## x
#  define PREFIX3(x) zng_ ## x
#  define PREFIX4(x) zng_ ## x
#  define zVersion zlibng_version
#  define z_size_t size_t
#endif

/* Minimum of a and b. */
#define MIN(a, b) ((a) > (b) ? (b) : (a))
/* Maximum of a and b. */
#define MAX(a, b) ((a) < (b) ? (b) : (a))
/* Ignore unused variable warning */
#define Z_UNUSED(var) (void)(var)

#if defined(HAVE_VISIBILITY_INTERNAL)
#  define Z_INTERNAL __attribute__((visibility ("internal")))
#elif defined(HAVE_VISIBILITY_HIDDEN)
#  define Z_INTERNAL __attribute__((visibility ("hidden")))
#else
#  define Z_INTERNAL
#endif

#ifndef __cplusplus
#  define Z_REGISTER register
#else
#  define Z_REGISTER
#endif

/* Reverse the bytes in a value. Use compiler intrinsics when
   possible to take advantage of hardware implementations. */
#if defined(_MSC_VER) && (_MSC_VER >= 1300)
#  include <stdlib.h>
#  pragma intrinsic(_byteswap_ulong)
#  define ZSWAP16(q) _byteswap_ushort(q)
#  define ZSWAP32(q) _byteswap_ulong(q)
#  define ZSWAP64(q) _byteswap_uint64(q)

#elif defined(__clang__) || (defined(__GNUC__) && \
        (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))
#  define ZSWAP16(q) __builtin_bswap16(q)
#  define ZSWAP32(q) __builtin_bswap32(q)
#  define ZSWAP64(q) __builtin_bswap64(q)

#elif defined(__GNUC__) && (__GNUC__ >= 2) && defined(__linux__)
#  include <byteswap.h>
#  define ZSWAP16(q) bswap_16(q)
#  define ZSWAP32(q) bswap_32(q)
#  define ZSWAP64(q) bswap_64(q)

#elif defined(__FreeBSD__) || defined(__NetBSD__) || defined(__DragonFly__)
#  include <sys/endian.h>
#  define ZSWAP16(q) bswap16(q)
#  define ZSWAP32(q) bswap32(q)
#  define ZSWAP64(q) bswap64(q)
#elif defined(__OpenBSD__)
#  include <sys/endian.h>
#  define ZSWAP16(q) swap16(q)
#  define ZSWAP32(q) swap32(q)
#  define ZSWAP64(q) swap64(q)
#elif defined(__INTEL_COMPILER)
/* ICC does not provide a two byte swap. */
#  define ZSWAP16(q) ((((q) & 0xff) << 8) | (((q) & 0xff00) >> 8))
#  define ZSWAP32(q) _bswap(q)
#  define ZSWAP64(q) _bswap64(q)

#else
#  define ZSWAP16(q) ((((q) & 0xff) << 8) | (((q) & 0xff00) >> 8))
#  define ZSWAP32(q) ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) + \
                     (((q) & 0xff00) << 8) + (((q) & 0xff) << 24))
#  define ZSWAP64(q)                           \
         (((q & 0xFF00000000000000u) >> 56u) | \
          ((q & 0x00FF000000000000u) >> 40u) | \
          ((q & 0x0000FF0000000000u) >> 24u) | \
          ((q & 0x000000FF00000000u) >> 8u)  | \
          ((q & 0x00000000FF000000u) << 8u)  | \
          ((q & 0x0000000000FF0000u) << 24u) | \
          ((q & 0x000000000000FF00u) << 40u) | \
          ((q & 0x00000000000000FFu) << 56u))
#endif

/* Only enable likely/unlikely if the compiler is known to support it */
#if (defined(__GNUC__) && (__GNUC__ >= 3)) || defined(__INTEL_COMPILER) || defined(__clang__)
#  define LIKELY_NULL(x)        __builtin_expect((x) != 0, 0)
#  define LIKELY(x)             __builtin_expect(!!(x), 1)
#  define UNLIKELY(x)           __builtin_expect(!!(x), 0)
#  define PREFETCH_L1(addr)     __builtin_prefetch(addr, 0, 3)
#  define PREFETCH_L2(addr)     __builtin_prefetch(addr, 0, 2)
#  define PREFETCH_RW(addr)     __builtin_prefetch(addr, 1, 2)
#elif defined(__WIN__)
#  include <xmmintrin.h>
#  define LIKELY_NULL(x)        x
#  define LIKELY(x)             x
#  define UNLIKELY(x)           x
#  define PREFETCH_L1(addr)     _mm_prefetch((char *) addr, _MM_HINT_T0)
#  define PREFETCH_L2(addr)     _mm_prefetch((char *) addr, _MM_HINT_T1)
#  define PREFETCH_RW(addr)     _mm_prefetch((char *) addr, _MM_HINT_T1)
#else
#  define LIKELY_NULL(x)        x
#  define LIKELY(x)             x
#  define UNLIKELY(x)           x
#  define PREFETCH_L1(addr)     addr
#  define PREFETCH_L2(addr)     addr
#  define PREFETCH_RW(addr)     addr
#endif /* (un)likely */

#if defined(__clang__) || defined(__GNUC__)
#  define ALIGNED_(x) __attribute__ ((aligned(x)))
#elif defined(_MSC_VER)
#  define ALIGNED_(x) __declspec(align(x))
#endif

/* Diagnostic functions */
#ifdef ZLIB_DEBUG
#  include <stdio.h>
   extern int Z_INTERNAL z_verbose;
   extern void Z_INTERNAL z_error(char *m);
#  define Assert(cond, msg) {if (!(cond)) z_error(msg);}
#  define Trace(x) {if (z_verbose >= 0) fprintf x;}
#  define Tracev(x) {if (z_verbose > 0) fprintf x;}
#  define Tracevv(x) {if (z_verbose > 1) fprintf x;}
#  define Tracec(c, x) {if (z_verbose > 0 && (c)) fprintf x;}
#  define Tracecv(c, x) {if (z_verbose > 1 && (c)) fprintf x;}
#else
#  define Assert(cond, msg)
#  define Trace(x)
#  define Tracev(x)
#  define Tracevv(x)
#  define Tracec(c, x)
#  define Tracecv(c, x)
#endif

#ifndef NO_UNALIGNED
#  if defined(__x86_64__) || defined(_M_X64) || defined(__amd64__) || defined(_M_AMD64)
#    define UNALIGNED_OK
#    define UNALIGNED64_OK
#  elif defined(__i386__) || defined(__i486__) || defined(__i586__) || \
        defined(__i686__) || defined(_X86_) || defined(_M_IX86)
#    define UNALIGNED_OK
#  elif defined(__aarch64__) || defined(_M_ARM64)
#    if (defined(__GNUC__) && defined(__ARM_FEATURE_UNALIGNED)) || !defined(__GNUC__)
#      define UNALIGNED_OK
#      define UNALIGNED64_OK
#    endif
#  elif defined(__arm__) || (_M_ARM >= 7)
#    if (defined(__GNUC__) && defined(__ARM_FEATURE_UNALIGNED)) || !defined(__GNUC__)
#      define UNALIGNED_OK
#    endif
#  elif defined(__powerpc64__) || defined(__ppc64__)
#    if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
#      define UNALIGNED_OK
#      define UNALIGNED64_OK
#    endif
#  endif
#endif

/* Force compiler to emit unaligned memory accesses if unaligned access is supported
   on the architecture, otherwise don't assume unaligned access is supported. Older
   compilers don't optimize memcpy and memcmp calls to unaligned access instructions
   when it is supported on the architecture resulting in significant performance impact.
   Newer compilers might optimize memcpy but not all optimize memcmp for all integer types. */
#ifdef UNALIGNED_OK
#  define zmemcpy_2(dest, src)    (*((uint16_t *)(dest)) = *((uint16_t *)(src)))
#  define zmemcmp_2(str1, str2)   (*((uint16_t *)(str1)) != *((uint16_t *)(str2)))
#  define zmemcpy_4(dest, src)    (*((uint32_t *)(dest)) = *((uint32_t *)(src)))
#  define zmemcmp_4(str1, str2)   (*((uint32_t *)(str1)) != *((uint32_t *)(str2)))
#  if defined(UNALIGNED64_OK) && (UINTPTR_MAX == UINT64_MAX)
#    define zmemcpy_8(dest, src)  (*((uint64_t *)(dest)) = *((uint64_t *)(src)))
#    define zmemcmp_8(str1, str2) (*((uint64_t *)(str1)) != *((uint64_t *)(str2)))
#  else
#    define zmemcpy_8(dest, src)  (((uint32_t *)(dest))[0] = ((uint32_t *)(src))[0], \
                                   ((uint32_t *)(dest))[1] = ((uint32_t *)(src))[1])
#    define zmemcmp_8(str1, str2) (((uint32_t *)(str1))[0] != ((uint32_t *)(str2))[0] || \
                                   ((uint32_t *)(str1))[1] != ((uint32_t *)(str2))[1])
#  endif
#else
#  define zmemcpy_2(dest, src)  memcpy(dest, src, 2)
#  define zmemcmp_2(str1, str2) memcmp(str1, str2, 2)
#  define zmemcpy_4(dest, src)  memcpy(dest, src, 4)
#  define zmemcmp_4(str1, str2) memcmp(str1, str2, 4)
#  define zmemcpy_8(dest, src)  memcpy(dest, src, 8)
#  define zmemcmp_8(str1, str2) memcmp(str1, str2, 8)
#endif

#if defined(__has_feature)
#  if __has_feature(memory_sanitizer)
#    define Z_MEMORY_SANITIZER 1
#    include <sanitizer/msan_interface.h>
#  endif
#endif

#endif