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128 lines
3.9 KiB
C++
128 lines
3.9 KiB
C++
/*
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* Copyright (C) Nemirtingas
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* This file is part of System.
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*
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* System is free software; you can redistribute it
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* and/or modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 3 of the License, or (at your option) any later version.
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*
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* System is distributed in the hope that it will be
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* useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with System; if not, see
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* <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <cstddef> // size_t
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#include <cstdint> // uint*_t
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namespace System {
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class Endian
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{
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private:
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template<typename T, size_t byte_count>
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struct ByteSwapImpl
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{
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constexpr static inline T swap(T v)
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{
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for (int i = 0; i < (byte_count/2); ++i)
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{
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uint8_t tmp = reinterpret_cast<uint8_t*>(&v)[i];
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reinterpret_cast<uint8_t*>(&v)[i] = reinterpret_cast<uint8_t*>(&v)[byte_count - i - 1];
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reinterpret_cast<uint8_t*>(&v)[byte_count - i - 1] = tmp;
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}
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return v;
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}
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};
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template<typename T>
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struct ByteSwapImpl<T, 1>
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{
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constexpr static inline T swap(T v) { return v; }
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};
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template<typename T>
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struct ByteSwapImpl<T, 2>
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{
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constexpr static inline T swap(T v)
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{
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uint16_t& tmp = *reinterpret_cast<uint16_t*>(&v);
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tmp = ((tmp & 0x00ffu) << 8)
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| ((tmp & 0xff00u) >> 8);
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return v;
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}
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};
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template<typename T>
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struct ByteSwapImpl<T, 4>
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{
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constexpr static inline T swap(T v)
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{
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uint32_t& tmp = *reinterpret_cast<uint32_t*>(&v);
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tmp = ((tmp & 0x000000fful) << 24)
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| ((tmp & 0x0000ff00ul) << 8)
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| ((tmp & 0x00ff0000ul) >> 8)
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| ((tmp & 0xff000000ul) >> 24);
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return v;
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}
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};
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template<typename T>
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struct ByteSwapImpl<T, 8>
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{
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constexpr static inline T swap(T v)
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{
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uint64_t& tmp = *reinterpret_cast<uint64_t*>(&v);
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tmp = ((tmp & 0x00000000000000ffull) << 56)
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| ((tmp & 0x000000000000ff00ull) << 40)
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| ((tmp & 0x0000000000ff0000ull) << 24)
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| ((tmp & 0x00000000ff000000ull) << 8)
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| ((tmp & 0x000000ff00000000ull) >> 8)
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| ((tmp & 0x0000ff0000000000ull) >> 24)
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| ((tmp & 0x00ff000000000000ull) >> 40)
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| ((tmp & 0xff00000000000000ull) >> 56);
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return v;
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}
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};
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public:
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static inline bool little()
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{
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const uint32_t endian_magic = 0x01020304;
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return reinterpret_cast<const uint8_t*>(&endian_magic)[0] == 0x04;
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}
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static inline bool big()
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{
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const uint32_t endian_magic = 0x01020304;
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return reinterpret_cast<const uint8_t*>(&endian_magic)[0] == 0x01;
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}
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template<typename T, size_t Size = sizeof(T)>
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constexpr static inline T net_swap(T v)
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{
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if(Endian::little())
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{
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return ByteSwapImpl<T, Size>::swap(v);
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}
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return v;
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}
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template<typename T, size_t Size = sizeof(T)>
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constexpr static inline T swap(T v)
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{
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return ByteSwapImpl<T, Size>::swap(v);
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}
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private:
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Endian() = delete;
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};
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} |