TypeFromSize.hpp

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#ifndef ESTD_TYPEFROMSIZE_HPP_
#define ESTD_TYPEFROMSIZE_HPP_

#include <type_traits>

#include <cstddef>
#include <cstdint>

#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)

namespace estd
{

namespace internal
{

template<size_t size>
struct TypeFromSize
{
    static_assert(size <= sizeof(uint64_t), "Max supported type is uint64_t!");

    using Type = typename std::conditional<size <= sizeof(uint8_t), uint8_t,
            typename std::conditional<size <= sizeof(uint16_t), uint16_t,
            typename std::conditional<size <= sizeof(uint32_t), uint32_t, uint64_t>::type>::type>::type;
};

}

template<size_t size>
using TypeFromSize = typename internal::TypeFromSize<size>::Type;

STATIC_ASSERT(std::is_same<TypeFromSize<0>, uint8_t>::value == true);
STATIC_ASSERT(std::is_same<TypeFromSize<1>, uint8_t>::value == true);
STATIC_ASSERT(std::is_same<TypeFromSize<2>, uint16_t>::value == true);
STATIC_ASSERT(std::is_same<TypeFromSize<3>, uint32_t>::value == true);
STATIC_ASSERT(std::is_same<TypeFromSize<4>, uint32_t>::value == true);
STATIC_ASSERT(std::is_same<TypeFromSize<5>, uint64_t>::value == true);
STATIC_ASSERT(std::is_same<TypeFromSize<6>, uint64_t>::value == true);
STATIC_ASSERT(std::is_same<TypeFromSize<7>, uint64_t>::value == true);
STATIC_ASSERT(std::is_same<TypeFromSize<8>, uint64_t>::value == true);

}   // namespace estd

#endif  // ESTD_TYPEFROMSIZE_HPP_