| // (C) Copyright John Maddock 2006. |
| // Use, modification and distribution are subject to the |
| // Boost Software License, Version 1.0. (See accompanying file |
| // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| |
| #ifndef BOOST_MATH_TOOLS_SIGN_HPP |
| #define BOOST_MATH_TOOLS_SIGN_HPP |
| |
| #ifdef _MSC_VER |
| #pragma once |
| #endif |
| |
| #include <boost/math/tools/config.hpp> |
| #include <boost/math/special_functions/math_fwd.hpp> |
| #include <boost/math/special_functions/detail/fp_traits.hpp> |
| |
| namespace boost{ namespace math{ |
| |
| namespace detail { |
| |
| #ifdef BOOST_MATH_USE_STD_FPCLASSIFY |
| template<class T> |
| inline int signbit_impl(T x, native_tag const&) |
| { |
| return (std::signbit)(x); |
| } |
| #endif |
| |
| template<class T> |
| inline int signbit_impl(T x, generic_tag<true> const&) |
| { |
| return x < 0; |
| } |
| |
| template<class T> |
| inline int signbit_impl(T x, generic_tag<false> const&) |
| { |
| return x < 0; |
| } |
| |
| template<class T> |
| inline int signbit_impl(T x, ieee_copy_all_bits_tag const&) |
| { |
| typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::type traits; |
| |
| BOOST_DEDUCED_TYPENAME traits::bits a; |
| traits::get_bits(x,a); |
| return a & traits::sign ? 1 : 0; |
| } |
| |
| template<class T> |
| inline int signbit_impl(T x, ieee_copy_leading_bits_tag const&) |
| { |
| typedef BOOST_DEDUCED_TYPENAME fp_traits<T>::type traits; |
| |
| BOOST_DEDUCED_TYPENAME traits::bits a; |
| traits::get_bits(x,a); |
| |
| return a & traits::sign ? 1 : 0; |
| } |
| } // namespace detail |
| |
| template<class T> int (signbit)(T x) |
| { //!< \brief return true if floating-point type t is NaN (Not A Number). |
| typedef typename detail::fp_traits<T>::type traits; |
| typedef typename traits::method method; |
| typedef typename boost::is_floating_point<T>::type fp_tag; |
| return detail::signbit_impl(x, method()); |
| } |
| |
| template <class T> |
| inline int sign BOOST_NO_MACRO_EXPAND(const T& z) |
| { |
| return (z == 0) ? 0 : (boost::math::signbit)(z) ? -1 : 1; |
| } |
| |
| template <class T> |
| inline T copysign BOOST_NO_MACRO_EXPAND(const T& x, const T& y) |
| { |
| BOOST_MATH_STD_USING |
| return fabs(x) * ((boost::math::signbit)(y) ? -1 : 1); |
| } |
| |
| } // namespace math |
| } // namespace boost |
| |
| |
| #endif // BOOST_MATH_TOOLS_SIGN_HPP |
| |
| |