parameter.h

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#pragma once
 
#include "assert.h"
 
#include <utility>
#include <type_traits>
 
#ifdef __cpp_constexpr_dynamic_alloc
#define BS_CONSTEXPR constexpr
#else // __cpp_constexpr_dynamic_alloc
#define BS_CONSTEXPR
#endif // __cpp_constexpr_dynamic_alloc
 
namespace bitstream
{
#ifdef BS_DEBUG_BREAK
    template<typename T>
    class out
    {
    public:
        BS_CONSTEXPR out(T& value) noexcept :
            m_Value(value),
            m_Constructed(false) {}
 
        out(const out&) = delete;
 
        out(out&&) = delete;
 
        BS_CONSTEXPR ~out()
        {
            if (!m_Constructed)
                BS_BREAKPOINT();
        }
 
        template<typename U, typename = std::enable_if_t<std::is_assignable_v<T&, U>>>
        BS_CONSTEXPR out& operator=(U&& arg) noexcept(std::is_nothrow_assignable_v<T&, U>)
        {
            m_Value = std::forward<U>(arg);
 
            m_Constructed = true;
 
            return *this;
        }
 
        BS_CONSTEXPR T* operator->() noexcept
        {
            m_Constructed = true;
            return &m_Value;
        }
 
        BS_CONSTEXPR T& operator*() noexcept
        {
            m_Constructed = true;
            return m_Value;
        }
 
    private:
        T& m_Value;
        bool m_Constructed;
    };
#else
    template<typename T>
    class out
    {
    public:
        BS_CONSTEXPR out(T& value) noexcept :
            m_Value(value) {}
 
        out(const out&) = delete;
 
        out(out&&) = delete;
 
        template<typename U, typename = std::enable_if_t<std::is_assignable_v<T&, U>>>
        BS_CONSTEXPR out& operator=(U&& arg) noexcept(std::is_nothrow_assignable_v<T&, U>)
        {
            m_Value = std::forward<U>(arg);
 
            return *this;
        }
 
        BS_CONSTEXPR T* operator->() noexcept { return &m_Value; }
 
        BS_CONSTEXPR T& operator*() noexcept { return m_Value; }
 
    private:
        T& m_Value;
    };
#endif
 
    template<typename T>
    using in = std::conditional_t<(sizeof(T) <= 16 && std::is_trivially_copy_constructible_v<T>), std::add_const_t<T>, std::add_lvalue_reference_t<std::add_const_t<T>>>;
 
    template<typename Stream, typename T>
    using inout = std::conditional_t<Stream::writing, in<T>, std::add_lvalue_reference_t<T>>;
 
 
    template<typename Lambda>
    class finally
    {
    public:
        constexpr finally(Lambda func) noexcept :
            m_Lambda(func) {}
 
        ~finally()
        {
            m_Lambda();
        }
 
    private:
        Lambda m_Lambda;
    };
 
    template<typename Lambda>
    finally(Lambda func) -> finally<Lambda>;
}