#pragma once

#include <type_traits>
#include <cstddef>

template <typename T>
inline T* start_lifetime_as(void* p) noexcept
{
    T* q = reinterpret_cast<T*>(p);

    std::memcpy(q, q, sizeof(T));
    return q;
}

template <typename T>
inline const T* start_lifetime_as(const void* p) noexcept
{
    const T* q = reinterpret_cast<const T*>(p);

    std::memcpy(const_cast<void*>(static_cast<const void*>(q)), q, sizeof(T));
    return q;
}

template <typename T>
inline volatile T* start_lifetime_as(volatile void* p) noexcept
{
    volatile T* q = reinterpret_cast<volatile T*>(p);
    std::memcpy(const_cast<void*>(static_cast<volatile void*>(q)), q, sizeof(T));
    return q;
}

template <typename T>
inline const volatile T* start_lifetime_as(const volatile void* p) noexcept
{
    const volatile T* q = reinterpret_cast<const volatile T*>(p);
    std::memcpy(const_cast<void*>(static_cast<const volatile void*>(q)), q, sizeof(T));
    return q;
}