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godotengine
GitHub Repository: godotengine/godot
 Path: blob/master/thirdparty/libwebp/src/utils/endian_inl_utils.h
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// Copyright 2014 Google Inc. All Rights Reserved.

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//

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// Use of this source code is governed by a BSD-style license

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// that can be found in the COPYING file in the root of the source

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// tree. An additional intellectual property rights grant can be found

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// in the file PATENTS. All contributing project authors may

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// be found in the AUTHORS file in the root of the source tree.

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// -----------------------------------------------------------------------------

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//

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// Endian related functions.

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#ifndef WEBP_UTILS_ENDIAN_INL_UTILS_H_

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#define WEBP_UTILS_ENDIAN_INL_UTILS_H_

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#ifdef HAVE_CONFIG_H

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#include "src/webp/config.h"

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#endif

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#include "src/dsp/dsp.h"

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#include "src/webp/types.h"

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#if defined(WORDS_BIGENDIAN)

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#define HToLE32 BSwap32

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#define HToLE16 BSwap16

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#else

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#define HToLE32(x) (x)

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#define HToLE16(x) (x)

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#endif

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#if !defined(HAVE_CONFIG_H)

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#if LOCAL_GCC_PREREQ(4,8) || __has_builtin(__builtin_bswap16)

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#define HAVE_BUILTIN_BSWAP16

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#endif

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#if LOCAL_GCC_PREREQ(4,3) || __has_builtin(__builtin_bswap32)

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#define HAVE_BUILTIN_BSWAP32

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#endif

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#if LOCAL_GCC_PREREQ(4,3) || __has_builtin(__builtin_bswap64)

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#define HAVE_BUILTIN_BSWAP64

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#endif

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#endif  // !HAVE_CONFIG_H

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static WEBP_INLINE uint16_t BSwap16(uint16_t x) {

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#if defined(HAVE_BUILTIN_BSWAP16)

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  return __builtin_bswap16(x);

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#elif defined(_MSC_VER)

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  return _byteswap_ushort(x);

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#else

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  // gcc will recognize a 'rorw $8, ...' here:

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  return (x >> 8) | ((x & 0xff) << 8);

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#endif  // HAVE_BUILTIN_BSWAP16

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}

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static WEBP_INLINE uint32_t BSwap32(uint32_t x) {

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#if defined(WEBP_USE_MIPS32_R2)

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  uint32_t ret;

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  __asm__ volatile (

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    "wsbh   %[ret], %[x]          \n\t"

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    "rotr   %[ret], %[ret],  16   \n\t"

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    : [ret]"=r"(ret)

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    : [x]"r"(x)

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  );

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  return ret;

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#elif defined(HAVE_BUILTIN_BSWAP32)

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  return __builtin_bswap32(x);

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#elif defined(__i386__) || defined(__x86_64__)

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  uint32_t swapped_bytes;

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  __asm__ volatile("bswap %0" : "=r"(swapped_bytes) : "0"(x));

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  return swapped_bytes;

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#elif defined(_MSC_VER)

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  return (uint32_t)_byteswap_ulong(x);

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#else

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  return (x >> 24) | ((x >> 8) & 0xff00) | ((x << 8) & 0xff0000) | (x << 24);

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#endif  // HAVE_BUILTIN_BSWAP32

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}

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static WEBP_INLINE uint64_t BSwap64(uint64_t x) {

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#if defined(HAVE_BUILTIN_BSWAP64)

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  return __builtin_bswap64(x);

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#elif defined(__x86_64__)

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  uint64_t swapped_bytes;

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  __asm__ volatile("bswapq %0" : "=r"(swapped_bytes) : "0"(x));

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  return swapped_bytes;

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#elif defined(_MSC_VER)

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  return (uint64_t)_byteswap_uint64(x);

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#else  // generic code for swapping 64-bit values (suggested by bdb@)

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  x = ((x & 0xffffffff00000000ull) >> 32) | ((x & 0x00000000ffffffffull) << 32);

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  x = ((x & 0xffff0000ffff0000ull) >> 16) | ((x & 0x0000ffff0000ffffull) << 16);

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  x = ((x & 0xff00ff00ff00ff00ull) >>  8) | ((x & 0x00ff00ff00ff00ffull) <<  8);

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  return x;

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#endif  // HAVE_BUILTIN_BSWAP64

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}

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#endif  // WEBP_UTILS_ENDIAN_INL_UTILS_H_

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