// 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 VPX_VPX_UTIL_ENDIAN_INL_H_

#define VPX_VPX_UTIL_ENDIAN_INL_H_

#include <stdlib.h>

#include "./vpx_config.h"

#include "vpx/vpx_integer.h"

#if defined(__GNUC__)

#define LOCAL_GCC_VERSION ((__GNUC__ << 8) | __GNUC_MINOR__)

#define LOCAL_GCC_PREREQ(maj, min) (LOCAL_GCC_VERSION >= (((maj) << 8) | (min)))

#else

#define LOCAL_GCC_VERSION 0

#define LOCAL_GCC_PREREQ(maj, min) 0

#endif

// handle clang compatibility

#ifndef __has_builtin

#define __has_builtin(x) 0

#endif

// 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

#define HToBE64(x) (x)

#define HToBE32(x) (x)

#else

#define HToLE32(x) (x)

#define HToLE16(x) (x)

#define HToBE64(X) BSwap64(X)

#define HToBE32(X) BSwap32(X)

#endif

#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

#if HAVE_MIPS32 && defined(__mips__) && !defined(__mips64) && \

    defined(__mips_isa_rev) && (__mips_isa_rev >= 2) && (__mips_isa_rev < 6)

#define VPX_USE_MIPS32_R2

#endif

static 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 INLINE uint32_t BSwap32(uint32_t x) {

#if defined(VPX_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 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  // VPX_VPX_UTIL_ENDIAN_INL_H_