mirror of
https://github.com/SerenityOS/serenity
synced 2024-07-22 10:36:24 +00:00
151b8b5984
Problem: - Constructors and conversion operators are not `constexpr`, but they can be. - `constexpr` is needed here so that other classes can add `constexpr` evaluation. Solution: - Add the `constexpr` keyword to the constructors and conversion operators. - Add `static_assert` tests which ensure the capability works.
140 lines
4 KiB
C++
140 lines
4 KiB
C++
/*
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* Copyright (c) 2020, the SerenityOS developers.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include <AK/Forward.h>
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#include <AK/Platform.h>
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namespace AK {
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template<typename T>
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ALWAYS_INLINE constexpr T convert_between_host_and_little_endian(T value)
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{
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#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
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return value;
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#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
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if constexpr (sizeof(T) == 8)
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return __builtin_bswap64(value);
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if constexpr (sizeof(T) == 4)
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return __builtin_bswap32(value);
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if constexpr (sizeof(T) == 2)
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return __builtin_bswap16(value);
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if constexpr (sizeof(T) == 1)
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return value;
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#endif
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}
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template<typename T>
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ALWAYS_INLINE constexpr T convert_between_host_and_big_endian(T value)
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{
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#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
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if constexpr (sizeof(T) == 8)
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return __builtin_bswap64(value);
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if constexpr (sizeof(T) == 4)
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return __builtin_bswap32(value);
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if constexpr (sizeof(T) == 2)
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return __builtin_bswap16(value);
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if constexpr (sizeof(T) == 1)
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return value;
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#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
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return value;
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#endif
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}
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template<typename T>
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ALWAYS_INLINE T convert_between_host_and_network_endian(T value)
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{
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return convert_between_host_and_big_endian(value);
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}
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template<typename T>
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class LittleEndian;
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template<typename T>
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InputStream& operator>>(InputStream&, LittleEndian<T>&);
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template<typename T>
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OutputStream& operator<<(OutputStream&, LittleEndian<T>);
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template<typename T>
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class [[gnu::packed]] LittleEndian
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{
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public:
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friend InputStream& operator>><T>(InputStream&, LittleEndian<T>&);
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friend OutputStream& operator<<<T>(OutputStream&, LittleEndian<T>);
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constexpr LittleEndian() { }
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constexpr LittleEndian(T value)
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: m_value(convert_between_host_and_little_endian(value))
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{
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}
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constexpr operator T() const { return convert_between_host_and_little_endian(m_value); }
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private:
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T m_value { 0 };
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};
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template<typename T>
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class BigEndian;
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template<typename T>
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InputStream& operator>>(InputStream&, BigEndian<T>&);
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template<typename T>
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OutputStream& operator<<(OutputStream&, BigEndian<T>);
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template<typename T>
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class [[gnu::packed]] BigEndian
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{
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public:
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friend InputStream& operator>><T>(InputStream&, BigEndian<T>&);
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friend OutputStream& operator<<<T>(OutputStream&, BigEndian<T>);
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constexpr BigEndian() = default;
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constexpr BigEndian(T value)
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: m_value(convert_between_host_and_big_endian(value))
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{
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}
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constexpr operator T() const { return convert_between_host_and_big_endian(m_value); }
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private:
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T m_value { 0 };
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};
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template<typename T>
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using NetworkOrdered = BigEndian<T>;
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}
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using AK::BigEndian;
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using AK::LittleEndian;
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using AK::NetworkOrdered;
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