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// 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_NO_LEXICAL_CAST
#include <boost/lexical_cast.hpp>
#endif
#include <boost/type_traits/is_convertible.hpp>
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;
};
#else
typedef long double largest_float;
#define BOOST_MATH_LARGEST_FLOAT_C(x) x##L
#endif
template <class T>
inline BOOST_CONSTEXPR_OR_CONST T make_big_value(largest_float v, const char*, mpl::true_ const&, mpl::false_ const&) BOOST_MATH_NOEXCEPT(T)
{
return static_cast<T>(v);
}
template <class T>
inline BOOST_CONSTEXPR_OR_CONST T make_big_value(largest_float v, const char*, mpl::true_ const&, mpl::true_ 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, mpl::false_ const&, mpl::false_ const&)
{
return boost::lexical_cast<T>(s);
}
#endif
template <class T>
inline BOOST_MATH_CONSTEXPR const char* make_big_value(largest_float, const char* s, mpl::false_ const&, mpl::true_ const&) BOOST_MATH_NOEXCEPT(T)
{
return 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), \
mpl::bool_< (is_convertible<boost::math::tools::largest_float, T>::value) && \
((D <= boost::math::tools::numeric_traits<boost::math::tools::largest_float>::digits) \
|| 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))) >(), \
boost::is_convertible<const char*, T>())
//
// 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), \
mpl::bool_<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)>(), \
boost::is_convertible<const char*, T>())
}}} // namespaces
#endif
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