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//===- SwapByteOrder.h - Generic and optimized byte swaps -------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares generic and optimized functions to swap the byte order of
// an integral type.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_SWAPBYTEORDER_H
#define LLVM_SUPPORT_SWAPBYTEORDER_H
#include "llvm/Support/Compiler.h"
#include "llvm/Support/DataTypes.h"
#include <cstddef>
#include <limits>
namespace llvm {
namespace sys {
/// SwapByteOrder_16 - This function returns a byte-swapped representation of
/// the 16-bit argument.
inline uint16_t SwapByteOrder_16(uint16_t value) {
#if defined(_MSC_VER) && !defined(_DEBUG)
// The DLL version of the runtime lacks these functions (bug!?), but in a
// release build they're replaced with BSWAP instructions anyway.
return _byteswap_ushort(value);
#else
uint16_t Hi = value << 8;
uint16_t Lo = value >> 8;
return Hi | Lo;
#endif
}
/// SwapByteOrder_32 - This function returns a byte-swapped representation of
/// the 32-bit argument.
inline uint32_t SwapByteOrder_32(uint32_t value) {
#if defined(__llvm__) || (LLVM_GNUC_PREREQ(4, 3, 0) && !defined(__ICC))
return __builtin_bswap32(value);
#elif defined(_MSC_VER) && !defined(_DEBUG)
return _byteswap_ulong(value);
#else
uint32_t Byte0 = value & 0x000000FF;
uint32_t Byte1 = value & 0x0000FF00;
uint32_t Byte2 = value & 0x00FF0000;
uint32_t Byte3 = value & 0xFF000000;
return (Byte0 << 24) | (Byte1 << 8) | (Byte2 >> 8) | (Byte3 >> 24);
#endif
}
/// SwapByteOrder_64 - This function returns a byte-swapped representation of
/// the 64-bit argument.
inline uint64_t SwapByteOrder_64(uint64_t value) {
#if defined(__llvm__) || (LLVM_GNUC_PREREQ(4, 3, 0) && !defined(__ICC))
return __builtin_bswap64(value);
#elif defined(_MSC_VER) && !defined(_DEBUG)
return _byteswap_uint64(value);
#else
uint64_t Hi = SwapByteOrder_32(uint32_t(value));
uint32_t Lo = SwapByteOrder_32(uint32_t(value >> 32));
return (Hi << 32) | Lo;
#endif
}
inline unsigned char getSwappedBytes(unsigned char C) { return C; }
inline signed char getSwappedBytes(signed char C) { return C; }
inline char getSwappedBytes(char C) { return C; }
inline unsigned short getSwappedBytes(unsigned short C) { return SwapByteOrder_16(C); }
inline signed short getSwappedBytes( signed short C) { return SwapByteOrder_16(C); }
inline unsigned int getSwappedBytes(unsigned int C) { return SwapByteOrder_32(C); }
inline signed int getSwappedBytes( signed int C) { return SwapByteOrder_32(C); }
#if __LONG_MAX__ == __INT_MAX__
inline unsigned long getSwappedBytes(unsigned long C) { return SwapByteOrder_32(C); }
inline signed long getSwappedBytes( signed long C) { return SwapByteOrder_32(C); }
#elif __LONG_MAX__ == __LONG_LONG_MAX__
inline unsigned long getSwappedBytes(unsigned long C) { return SwapByteOrder_64(C); }
inline signed long getSwappedBytes( signed long C) { return SwapByteOrder_64(C); }
#else
#error "Unknown long size!"
#endif
inline unsigned long long getSwappedBytes(unsigned long long C) {
return SwapByteOrder_64(C);
}
inline signed long long getSwappedBytes(signed long long C) {
return SwapByteOrder_64(C);
}
template<typename T>
inline void swapByteOrder(T &Value) {
Value = getSwappedBytes(Value);
}
} // end namespace sys
} // end namespace llvm
#endif
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