round.hpp

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// SPDX-License-Identifier: BSD-2-Clause
 
#ifndef pRC_CORE_VALUE_FUNCTIONS_ROUND_H
#define pRC_CORE_VALUE_FUNCTIONS_ROUND_H
 
#include <cmath>
 
#include <prc/core/basic/functions/ipow.hpp>
#include <prc/core/value/functions/div.hpp>
#include <prc/core/value/functions/mul.hpp>
#include <prc/core/value/value.hpp>
 
namespace pRC
{
    template<Size D = 0, Position P = Position::Right, IsFloat T>
        requires(P == Position::Right) || (P == Position::Left)
    static inline constexpr auto round(T const &a)
    {
        constexpr T scale = iPow(Size(10), D);
        if constexpr(P == Position::Right)
        {
            return Float(std::round((a * scale)())) / scale;
        }
        if constexpr(P == Position::Left)
        {
            return Float(std::round((a / scale)())) * scale;
        }
    }
 
    template<Size D = 0, Position P = Position::Right, IsInteger T>
        requires(P == Position::Right) || (P == Position::Left)
    static inline constexpr auto round(T const &a)
    {
        if constexpr(P == Position::Right)
        {
            return a;
        }
        if constexpr(P == Position::Left)
        {
            return cast<T>(round<D, P>(cast<Float<>>(a)));
        }
    }
}
#endif // pRC_CORE_VALUE_FUNCTIONS_ROUND_H