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101 lines
3.5 KiB
101 lines
3.5 KiB
//===- SwapByteOrder.h - Generic and optimized byte swaps -------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file declares generic and optimized functions to swap the byte order of
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// an integral type.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_SUPPORT_SWAPBYTEORDER_H
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#define LLVM_SUPPORT_SWAPBYTEORDER_H
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#include "llvm/Support/DataTypes.h"
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#include <cstddef>
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#include <limits>
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namespace llvm {
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namespace sys {
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/// SwapByteOrder_16 - This function returns a byte-swapped representation of
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/// the 16-bit argument.
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inline uint16_t SwapByteOrder_16(uint16_t value) {
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#if defined(_MSC_VER) && !defined(_DEBUG)
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// The DLL version of the runtime lacks these functions (bug!?), but in a
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// release build they're replaced with BSWAP instructions anyway.
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return _byteswap_ushort(value);
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#else
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uint16_t Hi = value << 8;
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uint16_t Lo = value >> 8;
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return Hi | Lo;
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#endif
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}
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/// SwapByteOrder_32 - This function returns a byte-swapped representation of
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/// the 32-bit argument.
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inline uint32_t SwapByteOrder_32(uint32_t value) {
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#if defined(__llvm__) || \
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(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)) && !defined(__ICC)
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return __builtin_bswap32(value);
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#elif defined(_MSC_VER) && !defined(_DEBUG)
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return _byteswap_ulong(value);
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#else
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uint32_t Byte0 = value & 0x000000FF;
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uint32_t Byte1 = value & 0x0000FF00;
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uint32_t Byte2 = value & 0x00FF0000;
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uint32_t Byte3 = value & 0xFF000000;
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return (Byte0 << 24) | (Byte1 << 8) | (Byte2 >> 8) | (Byte3 >> 24);
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#endif
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}
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/// SwapByteOrder_64 - This function returns a byte-swapped representation of
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/// the 64-bit argument.
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inline uint64_t SwapByteOrder_64(uint64_t value) {
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#if defined(__llvm__) || \
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(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)) && !defined(__ICC)
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return __builtin_bswap64(value);
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#elif defined(_MSC_VER) && !defined(_DEBUG)
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return _byteswap_uint64(value);
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#else
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uint64_t Hi = SwapByteOrder_32(uint32_t(value));
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uint32_t Lo = SwapByteOrder_32(uint32_t(value >> 32));
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return (Hi << 32) | Lo;
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#endif
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}
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inline unsigned char SwapByteOrder(unsigned char C) { return C; }
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inline signed char SwapByteOrder(signed char C) { return C; }
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inline char SwapByteOrder(char C) { return C; }
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inline unsigned short SwapByteOrder(unsigned short C) { return SwapByteOrder_16(C); }
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inline signed short SwapByteOrder( signed short C) { return SwapByteOrder_16(C); }
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inline unsigned int SwapByteOrder(unsigned int C) { return SwapByteOrder_32(C); }
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inline signed int SwapByteOrder( signed int C) { return SwapByteOrder_32(C); }
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#if __LONG_MAX__ == __INT_MAX__
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inline unsigned long SwapByteOrder(unsigned long C) { return SwapByteOrder_32(C); }
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inline signed long SwapByteOrder( signed long C) { return SwapByteOrder_32(C); }
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#elif __LONG_MAX__ == __LONG_LONG_MAX__
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inline unsigned long SwapByteOrder(unsigned long C) { return SwapByteOrder_64(C); }
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inline signed long SwapByteOrder( signed long C) { return SwapByteOrder_64(C); }
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#else
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#error "Unknown long size!"
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#endif
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inline unsigned long long SwapByteOrder(unsigned long long C) {
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return SwapByteOrder_64(C);
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}
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inline signed long long SwapByteOrder(signed long long C) {
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return SwapByteOrder_64(C);
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}
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} // end namespace sys
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} // end namespace llvm
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#endif
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