libwebp-0.6.0-rc1

third_party/libwebp/utils/endian_inl.h

-// Copyright 2014 Google Inc. All Rights Reserved.
-//
-// Use of this source code is governed by a BSD-style license
-// that can be found in the COPYING file in the root of the source
-// tree. An additional intellectual property rights grant can be found
-// in the file PATENTS. All contributing project authors may
-// be found in the AUTHORS file in the root of the source tree.
-// -----------------------------------------------------------------------------
-//
-// Endian related functions.
-
-#ifndef WEBP_UTILS_ENDIAN_INL_H_
-#define WEBP_UTILS_ENDIAN_INL_H_
-
-#ifdef HAVE_CONFIG_H
-#include "../webp/config.h"
-#endif
-
-#include "../dsp/dsp.h"
-#include "../webp/types.h"
-
-// some endian fix (e.g.: mips-gcc doesn't define __BIG_ENDIAN__)
-#if !defined(WORDS_BIGENDIAN) && \
-    (defined(__BIG_ENDIAN__) || defined(_M_PPC) || \
-     (defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)))
-#define WORDS_BIGENDIAN
-#endif
-
-#if defined(WORDS_BIGENDIAN)
-#define HToLE32 BSwap32
-#define HToLE16 BSwap16
-#else
-#define HToLE32(x) (x)
-#define HToLE16(x) (x)
-#endif
-
-#if !defined(HAVE_CONFIG_H)
-#if LOCAL_GCC_PREREQ(4,8) || __has_builtin(__builtin_bswap16)
-#define HAVE_BUILTIN_BSWAP16
-#endif
-#if LOCAL_GCC_PREREQ(4,3) || __has_builtin(__builtin_bswap32)
-#define HAVE_BUILTIN_BSWAP32
-#endif
-#if LOCAL_GCC_PREREQ(4,3) || __has_builtin(__builtin_bswap64)
-#define HAVE_BUILTIN_BSWAP64
-#endif
-#endif  // !HAVE_CONFIG_H
-
-static WEBP_INLINE uint16_t BSwap16(uint16_t x) {
-#if defined(HAVE_BUILTIN_BSWAP16)
-  return __builtin_bswap16(x);
-#elif defined(_MSC_VER)
-  return _byteswap_ushort(x);
-#else
-  // gcc will recognize a 'rorw $8, ...' here:
-  return (x >> 8) | ((x & 0xff) << 8);
-#endif  // HAVE_BUILTIN_BSWAP16
-}
-
-static WEBP_INLINE uint32_t BSwap32(uint32_t x) {
-#if defined(WEBP_USE_MIPS32_R2)
-  uint32_t ret;
-  __asm__ volatile (
-    "wsbh   %[ret], %[x]          \n\t"
-    "rotr   %[ret], %[ret],  16   \n\t"
-    : [ret]"=r"(ret)
-    : [x]"r"(x)
-  );
-  return ret;
-#elif defined(HAVE_BUILTIN_BSWAP32)
-  return __builtin_bswap32(x);
-#elif defined(__i386__) || defined(__x86_64__)
-  uint32_t swapped_bytes;
-  __asm__ volatile("bswap %0" : "=r"(swapped_bytes) : "0"(x));
-  return swapped_bytes;
-#elif defined(_MSC_VER)
-  return (uint32_t)_byteswap_ulong(x);
-#else
-  return (x >> 24) | ((x >> 8) & 0xff00) | ((x << 8) & 0xff0000) | (x << 24);
-#endif  // HAVE_BUILTIN_BSWAP32
-}
-
-static WEBP_INLINE uint64_t BSwap64(uint64_t x) {
-#if defined(HAVE_BUILTIN_BSWAP64)
-  return __builtin_bswap64(x);
-#elif defined(__x86_64__)
-  uint64_t swapped_bytes;
-  __asm__ volatile("bswapq %0" : "=r"(swapped_bytes) : "0"(x));
-  return swapped_bytes;
-#elif defined(_MSC_VER)
-  return (uint64_t)_byteswap_uint64(x);
-#else  // generic code for swapping 64-bit values (suggested by bdb@)
-  x = ((x & 0xffffffff00000000ull) >> 32) | ((x & 0x00000000ffffffffull) << 32);
-  x = ((x & 0xffff0000ffff0000ull) >> 16) | ((x & 0x0000ffff0000ffffull) << 16);
-  x = ((x & 0xff00ff00ff00ff00ull) >>  8) | ((x & 0x00ff00ff00ff00ffull) <<  8);
-  return x;
-#endif  // HAVE_BUILTIN_BSWAP64
-}
-
-#endif  // WEBP_UTILS_ENDIAN_INL_H_