abs.hpp

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// SPDX-License-Identifier: BSL-1.0
// SPDX-FileCopyrightText: Copyright (C) 2019 Tobias Hienzsch
 
#ifndef TETL_MATH_ABS_HPP
#define TETL_MATH_ABS_HPP
 
namespace etl {
namespace detail {
 
template <typename T>
[[nodiscard]] constexpr auto abs_impl(T n) noexcept -> T
{
    // constexpr auto isInt      = is_same_v<T, int>;
    // constexpr auto isLong     = is_same_v<T, long>;
    // constexpr auto isLongLong = is_same_v<T, long long>;
    // static_assert(isInt || isLong || isLongLong);
 
    if (n >= T(0)) {
        return n;
    }
    return n * T(-1);
}
 
} // namespace detail
 
/// \brief Computes the absolute value of an integer number. The behavior is
/// undefined if the result cannot be represented by the return type. If abs
/// is called with an unsigned integral argument that cannot be converted to int
/// by integral promotion, the program is ill-formed.
[[nodiscard]] constexpr auto abs(int n) noexcept -> int
{
    return detail::abs_impl<int>(n);
}
 
[[nodiscard]] constexpr auto abs(long n) noexcept -> long
{
    return detail::abs_impl<long>(n);
}
 
[[nodiscard]] constexpr auto abs(long long n) noexcept -> long long
{
    return detail::abs_impl<long long>(n);
}
 
[[nodiscard]] constexpr auto abs(float n) noexcept -> float
{
    return detail::abs_impl<float>(n);
}
 
[[nodiscard]] constexpr auto abs(double n) noexcept -> double
{
    return detail::abs_impl<double>(n);
}
 
[[nodiscard]] constexpr auto abs(long double n) noexcept -> long double
{
    return detail::abs_impl<long double>(n);
}
 
[[nodiscard]] constexpr auto fabs(float n) noexcept -> float
{
    return detail::abs_impl<float>(n);
}
 
[[nodiscard]] constexpr auto fabsf(float n) noexcept -> float
{
    return detail::abs_impl<float>(n);
}
 
[[nodiscard]] constexpr auto fabs(double n) noexcept -> double
{
    return detail::abs_impl<double>(n);
}
 
[[nodiscard]] constexpr auto fabs(long double n) noexcept -> long double
{
    return detail::abs_impl<long double>(n);
}
 
[[nodiscard]] constexpr auto fabsl(long double n) noexcept -> long double
{
    return detail::abs_impl<long double>(n);
}
 
} // namespace etl
 
#endif // TETL_MATH_ABS_HPP