// Copyright (c) 2011 John Maddock // 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_BIG_CONSTANT_HPP #define BOOST_MATH_TOOLS_BIG_CONSTANT_HPP #include <boost/math/tools/config.hpp> #ifndef BOOST_MATH_STANDALONE #include <boost/lexical_cast.hpp> #endif #include <cstdlib> #include <type_traits> #include <limits> namespace boost{ namespace math{ namespace tools{ template <class T> struct numeric_traits : public std::numeric_limits< T > {}; #ifdef BOOST_MATH_USE_FLOAT128 typedef __float128 largest_float; #define BOOST_MATH_LARGEST_FLOAT_C(x) x##Q template <> struct numeric_traits<__float128> { static const int digits = 113; static const int digits10 = 33; static const int max_exponent = 16384; static const bool is_specialized = true; }; #elif LDBL_DIG > DBL_DIG typedef long double largest_float; #define BOOST_MATH_LARGEST_FLOAT_C(x) x##L #else typedef double largest_float; #define BOOST_MATH_LARGEST_FLOAT_C(x) x #endif template <class T> inline constexpr T make_big_value(largest_float v, const char*, std::true_type const&, std::false_type const&) BOOST_MATH_NOEXCEPT(T) { return static_cast<T>(v); } template <class T> inline constexpr T make_big_value(largest_float v, const char*, std::true_type const&, std::true_type const&) BOOST_MATH_NOEXCEPT(T) { return static_cast<T>(v); } #ifndef BOOST_MATH_NO_LEXICAL_CAST template <class T> inline T make_big_value(largest_float, const char* s, std::false_type const&, std::false_type const&) { return boost::lexical_cast<T>(s); } #else template <typename T> inline T make_big_value(largest_float, const char* s, std::false_type const&, std::false_type const&) { static_assert(sizeof(T) == 0, "Type is unsupported in standalone mode. Please disable and try again."); } #endif template <class T> inline constexpr T make_big_value(largest_float, const char* s, std::false_type const&, std::true_type const&) BOOST_MATH_NOEXCEPT(T) { return T(s); } // // For constants which might fit in a long double (if it's big enough): // #define BOOST_MATH_BIG_CONSTANT(T, D, x)\ boost::math::tools::make_big_value<T>(\ BOOST_MATH_LARGEST_FLOAT_C(x), \ BOOST_STRINGIZE(x), \ std::integral_constant<bool, (std::is_convertible<boost::math::tools::largest_float, T>::value) && \ ((D <= boost::math::tools::numeric_traits<boost::math::tools::largest_float>::digits) \ || std::is_floating_point<T>::value \ || (boost::math::tools::numeric_traits<T>::is_specialized && \ (boost::math::tools::numeric_traits<T>::digits10 <= boost::math::tools::numeric_traits<boost::math::tools::largest_float>::digits10))) >(), \ std::is_constructible<T, const char*>()) // // For constants too huge for any conceivable long double (and which generate compiler errors if we try and declare them as such): // #define BOOST_MATH_HUGE_CONSTANT(T, D, x)\ boost::math::tools::make_big_value<T>(0.0L, BOOST_STRINGIZE(x), \ std::integral_constant<bool, std::is_floating_point<T>::value || (boost::math::tools::numeric_traits<T>::is_specialized && boost::math::tools::numeric_traits<T>::max_exponent <= boost::math::tools::numeric_traits<boost::math::tools::largest_float>::max_exponent && boost::math::tools::numeric_traits<T>::digits <= boost::math::tools::numeric_traits<boost::math::tools::largest_float>::digits)>(), \ std::is_constructible<T, const char*>()) }}} // namespaces #endif