math/ccmath/fmod.hpp

0001 //  (C) Copyright Matt Borland 2021 - 2022.
0002 //  Use, modification and distribution are subject to the
0003 //  Boost Software License, Version 1.0. (See accompanying file
0004 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0005
0006 #ifndef BOOST_MATH_CCMATH_FMOD_HPP
0007 #define BOOST_MATH_CCMATH_FMOD_HPP
0008
0009 #include <boost/math/ccmath/detail/config.hpp>
0010
0011 #ifdef BOOST_MATH_NO_CCMATH
0012 #error "The header <boost/math/fmod.hpp> can only be used in C++17 and later."
0013 #endif
0014
0015 #include <cstdint>
0016 #include <boost/math/tools/promotion.hpp>
0017 #include <boost/math/ccmath/abs.hpp>
0018 #include <boost/math/ccmath/isinf.hpp>
0019 #include <boost/math/ccmath/isnan.hpp>
0020 #include <boost/math/ccmath/isfinite.hpp>
0021
0022 namespace boost::math::ccmath {
0023
0024 namespace detail {
0025
0026 template <typename T>
0027 constexpr T fmod_impl(T x, T y)
0028 {
0029     if (x == y)
0030     {
0031         return static_cast<T>(0);
0032     }
0033     else
0034     {
0035         while (x >= y)
0036         {
0037             x -= y;
0038         }
0039
0040         return static_cast<T>(x);
0041     }
0042 }
0043
0044 } // Namespace detail
0045
0046 template <typename Real, std::enable_if_t<!std::is_integral_v<Real>, bool> = true>
0047 constexpr Real fmod(Real x, Real y)
0048 {
0049     if(BOOST_MATH_IS_CONSTANT_EVALUATED(x))
0050     {
0051         if (boost::math::ccmath::abs(x) == static_cast<Real>(0) && y != static_cast<Real>(0))
0052         {
0053             return x;
0054         }
0055         else if (boost::math::ccmath::isinf(x) && !boost::math::ccmath::isnan(y))
0056         {
0057             return std::numeric_limits<Real>::quiet_NaN();
0058         }
0059         else if (boost::math::ccmath::abs(y) == static_cast<Real>(0) && !boost::math::ccmath::isnan(x))
0060         {
0061             return std::numeric_limits<Real>::quiet_NaN();
0062         }
0063         else if (boost::math::ccmath::isinf(y) && boost::math::ccmath::isfinite(x))
0064         {
0065             return x;
0066         }
0067         else if (boost::math::ccmath::isnan(x))
0068         {
0069             return x;
0070         }
0071         else if (boost::math::ccmath::isnan(y))
0072         {
0073             return y;
0074         }
0075
0076         return boost::math::ccmath::detail::fmod_impl<Real>(x, y);
0077     }
0078     else
0079     {
0080         using std::fmod;
0081         return fmod(x, y);
0082     }
0083 }
0084
0085 template <typename T1, typename T2>
0086 constexpr auto fmod(T1 x, T2 y)
0087 {
0088     if(BOOST_MATH_IS_CONSTANT_EVALUATED(x))
0089     {
0090         using promoted_type = boost::math::tools::promote_args_t<T1, T2>;
0091         return boost::math::ccmath::fmod(promoted_type(x), promoted_type(y));
0092     }
0093     else
0094     {
0095         using std::fmod;
0096         return fmod(x, y);
0097     }
0098 }
0099
0100 constexpr float fmodf(float x, float y)
0101 {
0102     return boost::math::ccmath::fmod(x, y);
0103 }
0104
0105 #ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
0106 constexpr long double fmodl(long double x, long double y)
0107 {
0108     return boost::math::ccmath::fmod(x, y);
0109 }
0110 #endif
0111
0112 } // Namespaces
0113
0114 #endif // BOOST_MATH_CCMATH_FMOD_HPP