// (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 | |