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system/ByteOrder: use GCC built-ins if available

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This commit is contained in:
Max Kellermann 2015-02-12 11:05:02 +01:00
parent 6e66a5b77b
commit 821bc6d777
1 changed files with 38 additions and 6 deletions
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44
src/system/ByteOrder.hxx
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@ -1,5 +1,5 @@
/* /*
* Copyright (C) 2011-2013 Max Kellermann <max@duempel.org>, * Copyright (C) 2011-2015 Max Kellermann <max@duempel.org>,
* *
* Redistribution and use in source and binary forms, with or without * Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions * modification, are permitted provided that the following conditions
@ -30,6 +30,8 @@
#ifndef BYTE_ORDER_HXX #ifndef BYTE_ORDER_HXX
#define BYTE_ORDER_HXX #define BYTE_ORDER_HXX
#include "Compiler.h"
#include <stdint.h> #include <stdint.h>
#if defined(__i386__) || defined(__x86_64__) || defined(__ARMEL__) #if defined(__i386__) || defined(__x86_64__) || defined(__ARMEL__)
@ -74,24 +76,54 @@ IsBigEndian()
return IS_BIG_ENDIAN; return IS_BIG_ENDIAN;
} }
static inline constexpr uint16_t
GenericByteSwap16(uint16_t value)
{
return (value >> 8) | (value << 8);
}
static inline constexpr uint32_t
GenericByteSwap32(uint32_t value)
{
return (value >> 24) | ((value >> 8) & 0x0000ff00) |
((value << 8) & 0x00ff0000) | (value << 24);
}
static inline constexpr uint64_t
GenericByteSwap64(uint64_t value)
{
return uint64_t(GenericByteSwap32(uint32_t(value >> 32)))
| (uint64_t(GenericByteSwap32(value)) << 32);
}
static inline constexpr uint16_t static inline constexpr uint16_t
ByteSwap16(uint16_t value) ByteSwap16(uint16_t value)
{ {
return (value >> 8) | (value << 8); #if CLANG_OR_GCC_VERSION(4,8)
return __builtin_bswap16(value);
#else
return GenericByteSwap16(value);
#endif
} }
static inline constexpr uint32_t static inline constexpr uint32_t
ByteSwap32(uint32_t value) ByteSwap32(uint32_t value)
{ {
return (value >> 24) | ((value >> 8) & 0x0000ff00) | #if CLANG_OR_GCC_VERSION(4,3)
((value << 8) & 0x00ff0000) | (value << 24); return __builtin_bswap32(value);
#else
return GenericByteSwap32(value);
#endif
} }
static inline constexpr uint64_t static inline constexpr uint64_t
ByteSwap64(uint64_t value) ByteSwap64(uint64_t value)
{ {
return uint64_t(ByteSwap32(uint32_t(value >> 32))) #if CLANG_OR_GCC_VERSION(4,3)
| (uint64_t(ByteSwap32(value)) << 32); return __builtin_bswap64(value);
#else
return GenericByteSwap64(value);
#endif
} }
/** /**