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94 lines
2.3 KiB
C++
94 lines
2.3 KiB
C++
#pragma once
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#include <cstring>
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#include <type_traits>
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#include <bit>
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template <typename T>
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inline T unalignedLoad(const void * address)
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{
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T res {};
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memcpy(&res, address, sizeof(res));
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return res;
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}
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/// We've had troubles before with wrong store size due to integral promotions
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/// (e.g., unalignedStore(dest, uint16_t + uint16_t) stores an uint32_t).
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/// To prevent this, make the caller specify the stored type explicitly.
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/// To disable deduction of T, wrap the argument type with std::enable_if.
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template <typename T>
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inline void unalignedStore(void * address,
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const typename std::enable_if<true, T>::type & src)
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{
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static_assert(std::is_trivially_copyable_v<T>);
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memcpy(address, &src, sizeof(src));
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}
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inline void reverseMemcpy(void * dst, const void * src, size_t size)
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{
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uint8_t * uint_dst = reinterpret_cast<uint8_t *>(dst);
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const uint8_t * uint_src = reinterpret_cast<const uint8_t *>(src);
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uint_dst += size;
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while (size)
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{
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--uint_dst;
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*uint_dst = *uint_src;
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++uint_src;
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--size;
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}
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}
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template <std::endian endian, typename T>
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inline T unalignedLoadEndian(const void * address)
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{
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T res {};
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if constexpr (std::endian::native == endian)
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memcpy(&res, address, sizeof(res));
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else
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reverseMemcpy(&res, address, sizeof(res));
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return res;
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}
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template <std::endian endian, typename T>
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inline void unalignedStoreEndian(void * address, T & src)
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{
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static_assert(std::is_trivially_copyable_v<T>);
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if constexpr (std::endian::native == endian)
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memcpy(address, &src, sizeof(src));
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else
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reverseMemcpy(address, &src, sizeof(src));
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}
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template <typename T>
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inline T unalignedLoadLittleEndian(const void * address)
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{
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return unalignedLoadEndian<std::endian::little, T>(address);
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}
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template <typename T>
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inline void unalignedStoreLittleEndian(void * address,
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const typename std::enable_if<true, T>::type & src)
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{
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unalignedStoreEndian<std::endian::little>(address, src);
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}
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template <typename T>
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inline T unalignedLoadBigEndian(const void * address)
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{
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return unalignedLoadEndian<std::endian::big, T>(address);
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}
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template <typename T>
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inline void unalignedStoreBigEndian(void * address,
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const typename std::enable_if<true, T>::type & src)
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{
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unalignedStoreEndian<std::endian::big>(address, src);
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}
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