forked from OSchip/llvm-project
144 lines
4.5 KiB
C++
144 lines
4.5 KiB
C++
//===- endian.h - Endianness support ----------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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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 ORC_RT_ENDIAN_H
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#define ORC_RT_ENDIAN_H
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#include <cstddef>
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#include <cstdint>
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#include <type_traits>
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#if defined(_MSC_VER) && !defined(_DEBUG)
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#include <stdlib.h>
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#endif
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#if defined(__linux__) || defined(__GNU__) || defined(__HAIKU__) || \
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defined(__Fuchsia__) || defined(__EMSCRIPTEN__)
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#include <endian.h>
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#elif defined(_AIX)
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#include <sys/machine.h>
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#elif defined(__sun)
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/* Solaris provides _BIG_ENDIAN/_LITTLE_ENDIAN selector in sys/types.h */
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#include <sys/types.h>
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#define BIG_ENDIAN 4321
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#define LITTLE_ENDIAN 1234
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#if defined(_BIG_ENDIAN)
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#define BYTE_ORDER BIG_ENDIAN
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#else
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#define BYTE_ORDER LITTLE_ENDIAN
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#endif
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#elif defined(__MVS__)
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#define BIG_ENDIAN 4321
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#define LITTLE_ENDIAN 1234
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#define BYTE_ORDER BIG_ENDIAN
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#else
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#if !defined(BYTE_ORDER) && !defined(_WIN32)
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#include <machine/endian.h>
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#endif
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#endif
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namespace __orc_rt {
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/// ByteSwap_16 - This function returns a byte-swapped representation of
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/// the 16-bit argument.
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inline uint16_t ByteSwap_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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/// This function returns a byte-swapped representation of the 32-bit argument.
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inline uint32_t ByteSwap_32(uint32_t value) {
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#if defined(__llvm__) || (defined(__GNUC__) && !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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/// This function returns a byte-swapped representation of the 64-bit argument.
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inline uint64_t ByteSwap_64(uint64_t value) {
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#if defined(__llvm__) || (defined(__GNUC__) && !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 = ByteSwap_32(uint32_t(value));
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uint32_t Lo = ByteSwap_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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#if defined(BYTE_ORDER) && defined(BIG_ENDIAN) && BYTE_ORDER == BIG_ENDIAN
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constexpr bool IsBigEndianHost = true;
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#else
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constexpr bool IsBigEndianHost = false;
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#endif
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static const bool IsLittleEndianHost = !IsBigEndianHost;
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inline unsigned char getSwappedBytes(unsigned char C) { return C; }
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inline signed char getSwappedBytes(signed char C) { return C; }
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inline char getSwappedBytes(char C) { return C; }
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inline unsigned short getSwappedBytes(unsigned short C) {
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return ByteSwap_16(C);
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}
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inline signed short getSwappedBytes(signed short C) { return ByteSwap_16(C); }
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inline unsigned int getSwappedBytes(unsigned int C) { return ByteSwap_32(C); }
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inline signed int getSwappedBytes(signed int C) { return ByteSwap_32(C); }
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inline unsigned long getSwappedBytes(unsigned long C) {
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// Handle LLP64 and LP64 platforms.
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return sizeof(long) == sizeof(int) ? ByteSwap_32((uint32_t)C)
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: ByteSwap_64((uint64_t)C);
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}
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inline signed long getSwappedBytes(signed long C) {
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// Handle LLP64 and LP64 platforms.
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return sizeof(long) == sizeof(int) ? ByteSwap_32((uint32_t)C)
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: ByteSwap_64((uint64_t)C);
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}
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inline unsigned long long getSwappedBytes(unsigned long long C) {
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return ByteSwap_64(C);
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}
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inline signed long long getSwappedBytes(signed long long C) {
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return ByteSwap_64(C);
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}
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template <typename T>
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inline std::enable_if_t<std::is_enum<T>::value, T> getSwappedBytes(T C) {
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return static_cast<T>(
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getSwappedBytes(static_cast<std::underlying_type_t<T>>(C)));
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}
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template <typename T> inline void swapByteOrder(T &Value) {
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Value = getSwappedBytes(Value);
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}
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} // end namespace __orc_rt
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#endif // ORC_RT_ENDIAN_H
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