abs.hpp

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/*=============================================================================
  Copyright (C) 2015-2017 DxLibEx project
  https://github.com/Nagarei/DxLibEx/

  Distributed under the Boost Software License, Version 1.0.
  (See http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/
#ifndef DXLE_INC_CSTDLIB_ABS_HPP_
#define DXLE_INC_CSTDLIB_ABS_HPP_
#include "dxlibex/config/defines.h"
#include <cstdlib>
#include "dxlibex/type_traits/enable_if.hpp"
#include <type_traits>
#ifdef DXLE_NO_CXX11_CONSTEXPR
namespace dxle{
    using std::abs;
}
#else //DXLE_NO_CXX11_CONSTEXPR
namespace dxle {

    // 7.20.6.1 abs，labs，及び llabs 関数
    inline DXLE_CONSTEXPR int abs(int j) DXLE_NOEXCEPT_OR_NOTHROW
    {
        return j < 0 ? -j : j;
    }

    inline DXLE_CONSTEXPR long labs(long j) DXLE_NOEXCEPT_OR_NOTHROW
    {
        return j < 0 ? -j : j;
    }

    inline DXLE_CONSTEXPR long long llabs(long long j) DXLE_NOEXCEPT_OR_NOTHROW
    {
        return j < 0 ? -j : j;
    }

    inline DXLE_CONSTEXPR long abs(long j) DXLE_NOEXCEPT_OR_NOTHROW { return dxle::labs(j); }

    inline DXLE_CONSTEXPR long long abs(long long j) DXLE_NOEXCEPT_OR_NOTHROW { return dxle::llabs(j); }

    template<typename IntType, enable_if_t<std::is_integral<IntType>::value && std::is_signed<IntType>::value, std::nullptr_t> = nullptr>
    inline DXLE_CONSTEXPR IntType abs(IntType j) DXLE_NOEXCEPT_OR_NOTHROW
    {
        return j < 0 ? -j : j;
    }

}   // namespace dxle
#endif //DXLE_NO_CXX11_CONSTEXPR
namespace dxle{
    template<typename IntType, enable_if_t<std::is_integral<IntType>::value && std::is_unsigned<IntType>::value, std::nullptr_t> = nullptr>
    inline DXLE_CONSTEXPR IntType abs(IntType j) DXLE_NOEXCEPT_OR_NOTHROW
    {
        return j;
    }
}
#endif //DXLE_INC_CSTDLIB_ABS_HPP_