Repo created

TMessagesProj/jni/voip/webrtc/base/sys_byteorder.h

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+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This header defines cross-platform ByteSwap() implementations for 16, 32 and
+// 64-bit values, and NetToHostXX() / HostToNextXX() functions equivalent to
+// the traditional ntohX() and htonX() functions.
+// Use the functions defined here rather than using the platform-specific
+// functions directly.
+
+#ifndef BASE_SYS_BYTEORDER_H_
+#define BASE_SYS_BYTEORDER_H_
+
+#include <stdint.h>
+
+#include "build/build_config.h"
+
+#if defined(COMPILER_MSVC)
+#include <stdlib.h>
+#endif
+
+namespace base {
+
+// Returns a value with all bytes in |x| swapped, i.e. reverses the endianness.
+inline uint16_t ByteSwap(uint16_t x) {
+#if defined(COMPILER_MSVC)
+  return _byteswap_ushort(x);
+#else
+  return __builtin_bswap16(x);
+#endif
+}
+
+inline uint32_t ByteSwap(uint32_t x) {
+#if defined(COMPILER_MSVC)
+  return _byteswap_ulong(x);
+#else
+  return __builtin_bswap32(x);
+#endif
+}
+
+inline uint64_t ByteSwap(uint64_t x) {
+#if defined(COMPILER_MSVC)
+  return _byteswap_uint64(x);
+#else
+  return __builtin_bswap64(x);
+#endif
+}
+
+inline uintptr_t ByteSwapUintPtrT(uintptr_t x) {
+  // We do it this way because some build configurations are ILP32 even when
+  // defined(ARCH_CPU_64_BITS). Unfortunately, we can't use sizeof in #ifs. But,
+  // because these conditionals are constexprs, the irrelevant branches will
+  // likely be optimized away, so this construction should not result in code
+  // bloat.
+  static_assert(sizeof(uintptr_t) == 4 || sizeof(uintptr_t) == 8,
+                "Unsupported uintptr_t size");
+  if (sizeof(uintptr_t) == 4)
+    return ByteSwap(static_cast<uint32_t>(x));
+  return ByteSwap(static_cast<uint64_t>(x));
+}
+
+// Converts the bytes in |x| from host order (endianness) to little endian, and
+// returns the result.
+inline uint16_t ByteSwapToLE16(uint16_t x) {
+#if defined(ARCH_CPU_LITTLE_ENDIAN)
+  return x;
+#else
+  return ByteSwap(x);
+#endif
+}
+inline uint32_t ByteSwapToLE32(uint32_t x) {
+#if defined(ARCH_CPU_LITTLE_ENDIAN)
+  return x;
+#else
+  return ByteSwap(x);
+#endif
+}
+inline uint64_t ByteSwapToLE64(uint64_t x) {
+#if defined(ARCH_CPU_LITTLE_ENDIAN)
+  return x;
+#else
+  return ByteSwap(x);
+#endif
+}
+
+// Converts the bytes in |x| from network to host order (endianness), and
+// returns the result.
+inline uint16_t NetToHost16(uint16_t x) {
+#if defined(ARCH_CPU_LITTLE_ENDIAN)
+  return ByteSwap(x);
+#else
+  return x;
+#endif
+}
+inline uint32_t NetToHost32(uint32_t x) {
+#if defined(ARCH_CPU_LITTLE_ENDIAN)
+  return ByteSwap(x);
+#else
+  return x;
+#endif
+}
+inline uint64_t NetToHost64(uint64_t x) {
+#if defined(ARCH_CPU_LITTLE_ENDIAN)
+  return ByteSwap(x);
+#else
+  return x;
+#endif
+}
+
+// Converts the bytes in |x| from host to network order (endianness), and
+// returns the result.
+inline uint16_t HostToNet16(uint16_t x) {
+#if defined(ARCH_CPU_LITTLE_ENDIAN)
+  return ByteSwap(x);
+#else
+  return x;
+#endif
+}
+inline uint32_t HostToNet32(uint32_t x) {
+#if defined(ARCH_CPU_LITTLE_ENDIAN)
+  return ByteSwap(x);
+#else
+  return x;
+#endif
+}
+inline uint64_t HostToNet64(uint64_t x) {
+#if defined(ARCH_CPU_LITTLE_ENDIAN)
+  return ByteSwap(x);
+#else
+  return x;
+#endif
+}
+
+}  // namespace base
+
+#endif  // BASE_SYS_BYTEORDER_H_