mirror of
https://github.com/SerenityOS/serenity
synced 2024-07-09 09:40:45 +00:00
94f5389934
Previously we were using the preprocessor everywhere we needed this constant, so let's move away from that and use a constexpr constant.
149 lines
4.2 KiB
C++
149 lines
4.2 KiB
C++
/*
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* Copyright (c) 2020, the SerenityOS developers.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Format.h>
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#include <AK/Forward.h>
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#include <AK/Platform.h>
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#if defined(AK_OS_MACOS)
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# include <libkern/OSByteOrder.h>
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# include <machine/endian.h>
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# define htobe16(x) OSSwapHostToBigInt16(x)
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# define htole16(x) OSSwapHostToLittleInt16(x)
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# define be16toh(x) OSSwapBigToHostInt16(x)
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# define le16toh(x) OSSwapLittleToHostInt16(x)
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# define htobe32(x) OSSwapHostToBigInt32(x)
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# define htole32(x) OSSwapHostToLittleInt32(x)
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# define be32toh(x) OSSwapBigToHostInt32(x)
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# define le32toh(x) OSSwapLittleToHostInt32(x)
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# define htobe64(x) OSSwapHostToBigInt64(x)
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# define htole64(x) OSSwapHostToLittleInt64(x)
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# define be64toh(x) OSSwapBigToHostInt64(x)
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# define le64toh(x) OSSwapLittleToHostInt64(x)
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# define __BIG_ENDIAN BIG_ENDIAN
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# define __LITTLE_ENDIAN LITTLE_ENDIAN
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# define __BYTE_ORDER BYTE_ORDER
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#endif
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namespace AK {
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#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
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inline constexpr static bool HostIsLittleEndian = true;
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#else
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inline constexpr static bool HostIsLittleEndian = false;
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#endif
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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 constexpr (HostIsLittleEndian || sizeof(T) == 1)
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return value;
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else if constexpr (sizeof(T) == 8)
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return static_cast<T>(__builtin_bswap64(static_cast<u64>(value)));
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else if constexpr (sizeof(T) == 4)
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return static_cast<T>(__builtin_bswap32(static_cast<u32>(value)));
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else if constexpr (sizeof(T) == 2)
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return static_cast<T>(__builtin_bswap16(static_cast<u16>(value)));
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else
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static_assert(DependentFalse<T>, "Cannot byte-swap values larger than 64-bits");
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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 constexpr (sizeof(T) == 1 || !HostIsLittleEndian)
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return value;
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else if constexpr (sizeof(T) == 8)
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return static_cast<T>(__builtin_bswap64(static_cast<u64>(value)));
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else if constexpr (sizeof(T) == 4)
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return static_cast<T>(__builtin_bswap32(static_cast<u32>(value)));
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else if constexpr (sizeof(T) == 2)
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return static_cast<T>(__builtin_bswap16(static_cast<u16>(value)));
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else
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static_assert(DependentFalse<T>, "Cannot byte-swap values larger than 64-bits");
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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 [[gnu::packed]] LittleEndian {
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public:
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constexpr LittleEndian() = default;
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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 [[gnu::packed]] BigEndian {
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public:
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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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template<typename T>
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requires(HasFormatter<T>) struct Formatter<LittleEndian<T>> : Formatter<T> {
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};
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template<typename T>
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requires(HasFormatter<T>) struct Formatter<BigEndian<T>> : Formatter<T> {
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};
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template<typename T>
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struct Traits<LittleEndian<T>> : public GenericTraits<LittleEndian<T>> {
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static constexpr bool is_trivially_serializable() { return Traits<T>::is_trivially_serializable(); }
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};
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template<typename T>
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struct Traits<BigEndian<T>> : public GenericTraits<BigEndian<T>> {
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static constexpr bool is_trivially_serializable() { return Traits<T>::is_trivially_serializable(); }
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};
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constexpr u16 bitswap(u16 v)
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{
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v = ((v >> 1) & 0x5555) | ((v & 0x5555) << 1); // even & odd bits
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v = ((v >> 2) & 0x3333) | ((v & 0x3333) << 2); // pairs
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v = ((v >> 4) & 0x0F0F) | ((v & 0x0F0F) << 4); // nibbles
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return ((v >> 8) & 0x00FF) | ((v & 0x00FF) << 8); // bytes
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}
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}
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#if USING_AK_GLOBALLY
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using AK::BigEndian;
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using AK::bitswap;
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using AK::LittleEndian;
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using AK::NetworkOrdered;
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#endif
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