Revert of Reland: Use native (optimized) functions for byte order conversion.

webrtc/base/byteorder.h

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE 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.
  */
 
 #ifndef WEBRTC_BASE_BYTEORDER_H_
 #define WEBRTC_BASE_BYTEORDER_H_
 
 #if defined(WEBRTC_POSIX) && !defined(__native_client__)
 #include <arpa/inet.h>
 #endif
 
+#if defined(WEBRTC_WIN)
+#include <stdlib.h>
+#endif
+
 #include "webrtc/base/basictypes.h"
 
-#if defined(WEBRTC_MAC)
-#include <libkern/OSByteOrder.h>
-
-#define htobe16(v) OSSwapHostToBigInt16(v)
-#define htobe32(v) OSSwapHostToBigInt32(v)
-#define htobe64(v) OSSwapHostToBigInt64(v)
-#define be16toh(v) OSSwapBigToHostInt16(v)
-#define be32toh(v) OSSwapBigToHostInt32(v)
-#define be64toh(v) OSSwapBigToHostInt64(v)
-
-#define htole16(v) OSSwapHostToLittleInt16(v)
-#define htole32(v) OSSwapHostToLittleInt32(v)
-#define htole64(v) OSSwapHostToLittleInt64(v)
-#define le16toh(v) OSSwapLittleToHostInt16(v)
-#define le32toh(v) OSSwapLittleToHostInt32(v)
-#define le64toh(v) OSSwapLittleToHostInt64(v)
-#elif defined(WEBRTC_WIN) || defined(__native_client__)
-
-#if defined(WEBRTC_WIN)
-#include <stdlib.h>
-#include <winsock2.h>
-#else
-#include <netinet/in.h>
-#endif
-
-#define htobe16(v) htons(v)
-#define htobe32(v) htonl(v)
-#define be16toh(v) ntohs(v)
-#define be32toh(v) ntohl(v)
-#if defined(WEBRTC_WIN)
-#define htobe64(v) htonll(v)
-#define be64toh(v) ntohll(v)
-#endif
-
-#if defined(RTC_ARCH_CPU_LITTLE_ENDIAN)
-#define htole16(v) (v)
-#define htole32(v) (v)
-#define htole64(v) (v)
-#define le16toh(v) (v)
-#define le32toh(v) (v)
-#define le64toh(v) (v)
-#if defined(__native_client__)
-#define htobe64(v) __builtin_bswap64(v)
-#define be64toh(v) __builtin_bswap64(v)
-#endif
-#elif defined(RTC_ARCH_CPU_BIG_ENDIAN)
-#define htole16(v) __builtin_bswap16(v)
-#define htole32(v) __builtin_bswap32(v)
-#define htole64(v) __builtin_bswap64(v)
-#define le16toh(v) __builtin_bswap16(v)
-#define le32toh(v) __builtin_bswap32(v)
-#define le64toh(v) __builtin_bswap64(v)
-#if defined(__native_client__)
-#define htobe64(v) (v)
-#define be64toh(v) (v)
-#endif
-#else
-#error RTC_ARCH_CPU_BIG_ENDIAN or RTC_ARCH_CPU_LITTLE_ENDIAN must be defined.
-#endif  // defined(RTC_ARCH_CPU_LITTLE_ENDIAN)
-#elif defined(WEBRTC_POSIX)
-#include <endian.h>
-#endif
-
 namespace rtc {
 
 // Reading and writing of little and big-endian numbers from memory
+// TODO: Optimized versions, with direct read/writes of
+// integers in host-endian format, when the platform supports it.
 
 inline void Set8(void* memory, size_t offset, uint8_t v) {
   static_cast<uint8_t*>(memory)[offset] = v;
 }
 
 inline uint8_t Get8(const void* memory, size_t offset) {
   return static_cast<const uint8_t*>(memory)[offset];
 }
 
 inline void SetBE16(void* memory, uint16_t v) {
-  *static_cast<uint16_t*>(memory) = htobe16(v);
+  Set8(memory, 0, static_cast<uint8_t>(v >> 8));
+  Set8(memory, 1, static_cast<uint8_t>(v >> 0));
 }
 
 inline void SetBE32(void* memory, uint32_t v) {
-  *static_cast<uint32_t*>(memory) = htobe32(v);
+  Set8(memory, 0, static_cast<uint8_t>(v >> 24));
+  Set8(memory, 1, static_cast<uint8_t>(v >> 16));
+  Set8(memory, 2, static_cast<uint8_t>(v >> 8));
+  Set8(memory, 3, static_cast<uint8_t>(v >> 0));
 }
 
 inline void SetBE64(void* memory, uint64_t v) {
-  *static_cast<uint64_t*>(memory) = htobe64(v);
+  Set8(memory, 0, static_cast<uint8_t>(v >> 56));
+  Set8(memory, 1, static_cast<uint8_t>(v >> 48));
+  Set8(memory, 2, static_cast<uint8_t>(v >> 40));
+  Set8(memory, 3, static_cast<uint8_t>(v >> 32));
+  Set8(memory, 4, static_cast<uint8_t>(v >> 24));
+  Set8(memory, 5, static_cast<uint8_t>(v >> 16));
+  Set8(memory, 6, static_cast<uint8_t>(v >> 8));
+  Set8(memory, 7, static_cast<uint8_t>(v >> 0));
 }
 
 inline uint16_t GetBE16(const void* memory) {
-  return be16toh(*static_cast<const uint16_t*>(memory));
+  return static_cast<uint16_t>((Get8(memory, 0) << 8) | (Get8(memory, 1) << 0));
 }
 
 inline uint32_t GetBE32(const void* memory) {
-  return be32toh(*static_cast<const uint32_t*>(memory));
+  return (static_cast<uint32_t>(Get8(memory, 0)) << 24) |
+         (static_cast<uint32_t>(Get8(memory, 1)) << 16) |
+         (static_cast<uint32_t>(Get8(memory, 2)) << 8) |
+         (static_cast<uint32_t>(Get8(memory, 3)) << 0);
 }
 
 inline uint64_t GetBE64(const void* memory) {
-  return be64toh(*static_cast<const uint64_t*>(memory));
+  return (static_cast<uint64_t>(Get8(memory, 0)) << 56) |
+         (static_cast<uint64_t>(Get8(memory, 1)) << 48) |
+         (static_cast<uint64_t>(Get8(memory, 2)) << 40) |
+         (static_cast<uint64_t>(Get8(memory, 3)) << 32) |
+         (static_cast<uint64_t>(Get8(memory, 4)) << 24) |
+         (static_cast<uint64_t>(Get8(memory, 5)) << 16) |
+         (static_cast<uint64_t>(Get8(memory, 6)) << 8) |
+         (static_cast<uint64_t>(Get8(memory, 7)) << 0);
 }
 
 inline void SetLE16(void* memory, uint16_t v) {
-  *static_cast<uint16_t*>(memory) = htole16(v);
+  Set8(memory, 0, static_cast<uint8_t>(v >> 0));
+  Set8(memory, 1, static_cast<uint8_t>(v >> 8));
 }
 
 inline void SetLE32(void* memory, uint32_t v) {
-  *static_cast<uint32_t*>(memory) = htole32(v);
+  Set8(memory, 0, static_cast<uint8_t>(v >> 0));
+  Set8(memory, 1, static_cast<uint8_t>(v >> 8));
+  Set8(memory, 2, static_cast<uint8_t>(v >> 16));
+  Set8(memory, 3, static_cast<uint8_t>(v >> 24));
 }
 
 inline void SetLE64(void* memory, uint64_t v) {
-  *static_cast<uint64_t*>(memory) = htole64(v);
+  Set8(memory, 0, static_cast<uint8_t>(v >> 0));
+  Set8(memory, 1, static_cast<uint8_t>(v >> 8));
+  Set8(memory, 2, static_cast<uint8_t>(v >> 16));
+  Set8(memory, 3, static_cast<uint8_t>(v >> 24));
+  Set8(memory, 4, static_cast<uint8_t>(v >> 32));
+  Set8(memory, 5, static_cast<uint8_t>(v >> 40));
+  Set8(memory, 6, static_cast<uint8_t>(v >> 48));
+  Set8(memory, 7, static_cast<uint8_t>(v >> 56));
 }
 
 inline uint16_t GetLE16(const void* memory) {
-  return le16toh(*static_cast<const uint16_t*>(memory));
+  return static_cast<uint16_t>((Get8(memory, 0) << 0) | (Get8(memory, 1) << 8));
 }
 
 inline uint32_t GetLE32(const void* memory) {
-  return le32toh(*static_cast<const uint32_t*>(memory));
+  return (static_cast<uint32_t>(Get8(memory, 0)) << 0) |
+         (static_cast<uint32_t>(Get8(memory, 1)) << 8) |
+         (static_cast<uint32_t>(Get8(memory, 2)) << 16) |
+         (static_cast<uint32_t>(Get8(memory, 3)) << 24);
 }
 
 inline uint64_t GetLE64(const void* memory) {
-  return le64toh(*static_cast<const uint64_t*>(memory));
+  return (static_cast<uint64_t>(Get8(memory, 0)) << 0) |
+         (static_cast<uint64_t>(Get8(memory, 1)) << 8) |
+         (static_cast<uint64_t>(Get8(memory, 2)) << 16) |
+         (static_cast<uint64_t>(Get8(memory, 3)) << 24) |
+         (static_cast<uint64_t>(Get8(memory, 4)) << 32) |
+         (static_cast<uint64_t>(Get8(memory, 5)) << 40) |
+         (static_cast<uint64_t>(Get8(memory, 6)) << 48) |
+         (static_cast<uint64_t>(Get8(memory, 7)) << 56);
 }
 
 // Check if the current host is big endian.
 inline bool IsHostBigEndian() {
-#if defined(RTC_ARCH_CPU_BIG_ENDIAN)
-  return true;
-#else
-  return false;
-#endif
+  static const int number = 1;
+  return 0 == *reinterpret_cast<const char*>(&number);
 }
 
 inline uint16_t HostToNetwork16(uint16_t n) {
-  return htobe16(n);
+  uint16_t result;
+  SetBE16(&result, n);
+  return result;
 }
 
 inline uint32_t HostToNetwork32(uint32_t n) {
-  return htobe32(n);
+  uint32_t result;
+  SetBE32(&result, n);
+  return result;
 }
 
 inline uint64_t HostToNetwork64(uint64_t n) {
-  return htobe64(n);
+  uint64_t result;
+  SetBE64(&result, n);
+  return result;
 }
 
 inline uint16_t NetworkToHost16(uint16_t n) {
-  return be16toh(n);
+  return GetBE16(&n);
 }
 
 inline uint32_t NetworkToHost32(uint32_t n) {
-  return be32toh(n);
+  return GetBE32(&n);
 }
 
 inline uint64_t NetworkToHost64(uint64_t n) {
-  return be64toh(n);
+  return GetBE64(&n);
 }
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_BYTEORDER_H_