BitUtils: Constexpr BitCastToArray, Remove BitCastFromArray

`std::bit_cast` participates in overload resolution only if `sizeof(To) == sizeof(From)` and both `To` and `From` are *TriviallyCopyable* types, so the static assertions here can be removed. `[[nodiscard]]` was added as well.
This commit is contained in:
mitaclaw
2024-06-24 00:05:46 -07:00
parent c536754ffe
commit 6ffd71ffae
3 changed files with 7 additions and 46 deletions

View File

@ -4,6 +4,7 @@
#pragma once
#include <array>
#include <bit>
#include <climits>
#include <cstddef>
#include <cstdint>
@ -166,50 +167,10 @@ inline auto BitCastPtr(PtrType* ptr) noexcept -> BitCastPtrType<T, PtrType>
}
// Similar to BitCastPtr, but specifically for aliasing structs to arrays.
template <typename ArrayType, typename T,
typename Container = std::array<ArrayType, sizeof(T) / sizeof(ArrayType)>>
inline auto BitCastToArray(const T& obj) noexcept -> Container
template <typename ValueType, typename From>
[[nodiscard]] constexpr auto BitCastToArray(const From& obj) noexcept
{
static_assert(sizeof(T) % sizeof(ArrayType) == 0,
"Size of array type must be a factor of size of source type.");
static_assert(std::is_trivially_copyable<T>(),
"BitCastToArray source type must be trivially copyable.");
static_assert(std::is_trivially_copyable<Container>(),
"BitCastToArray array type must be trivially copyable.");
Container result;
std::memcpy(result.data(), &obj, sizeof(T));
return result;
}
template <typename ArrayType, typename T,
typename Container = std::array<ArrayType, sizeof(T) / sizeof(ArrayType)>>
inline void BitCastFromArray(const Container& array, T& obj) noexcept
{
static_assert(sizeof(T) % sizeof(ArrayType) == 0,
"Size of array type must be a factor of size of destination type.");
static_assert(std::is_trivially_copyable<Container>(),
"BitCastFromArray array type must be trivially copyable.");
static_assert(std::is_trivially_copyable<T>(),
"BitCastFromArray destination type must be trivially copyable.");
std::memcpy(&obj, array.data(), sizeof(T));
}
template <typename ArrayType, typename T,
typename Container = std::array<ArrayType, sizeof(T) / sizeof(ArrayType)>>
inline auto BitCastFromArray(const Container& array) noexcept -> T
{
static_assert(sizeof(T) % sizeof(ArrayType) == 0,
"Size of array type must be a factor of size of destination type.");
static_assert(std::is_trivially_copyable<Container>(),
"BitCastFromArray array type must be trivially copyable.");
static_assert(std::is_trivially_copyable<T>(),
"BitCastFromArray destination type must be trivially copyable.");
T obj;
std::memcpy(&obj, array.data(), sizeof(T));
return obj;
return std::bit_cast<std::array<ValueType, sizeof(From) / sizeof(ValueType)>>(obj);
}
template <typename T>