1 | |
2 | // Copyright (c) 2011 John Maddock |
3 | // Use, modification and distribution are subject to the |
4 | // Boost Software License, Version 1.0. (See accompanying file |
5 | // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
6 | |
7 | #ifndef BOOST_MATH_TOOLS_BIG_CONSTANT_HPP |
8 | #define BOOST_MATH_TOOLS_BIG_CONSTANT_HPP |
9 | |
10 | #include <boost/math/tools/config.hpp> |
11 | #ifndef BOOST_MATH_NO_LEXICAL_CAST |
12 | #include <boost/lexical_cast.hpp> |
13 | #endif |
14 | #include <boost/type_traits/is_constructible.hpp> |
15 | #include <boost/type_traits/is_convertible.hpp> |
16 | #include <boost/type_traits/is_floating_point.hpp> |
17 | |
18 | namespace boost{ namespace math{ |
19 | |
20 | namespace tools{ |
21 | |
22 | template <class T> |
23 | struct numeric_traits : public std::numeric_limits< T > {}; |
24 | |
25 | #ifdef BOOST_MATH_USE_FLOAT128 |
26 | typedef __float128 largest_float; |
27 | #define BOOST_MATH_LARGEST_FLOAT_C(x) x##Q |
28 | template <> |
29 | struct numeric_traits<__float128> |
30 | { |
31 | static const int digits = 113; |
32 | static const int digits10 = 33; |
33 | static const int max_exponent = 16384; |
34 | static const bool is_specialized = true; |
35 | }; |
36 | #else |
37 | typedef long double largest_float; |
38 | #define BOOST_MATH_LARGEST_FLOAT_C(x) x##L |
39 | #endif |
40 | |
41 | template <class T> |
42 | inline BOOST_CONSTEXPR_OR_CONST T make_big_value(largest_float v, const char*, boost::true_type const&, boost::false_type const&) BOOST_MATH_NOEXCEPT(T) |
43 | { |
44 | return static_cast<T>(v); |
45 | } |
46 | template <class T> |
47 | inline BOOST_CONSTEXPR_OR_CONST T make_big_value(largest_float v, const char*, boost::true_type const&, boost::true_type const&) BOOST_MATH_NOEXCEPT(T) |
48 | { |
49 | return static_cast<T>(v); |
50 | } |
51 | #ifndef BOOST_MATH_NO_LEXICAL_CAST |
52 | template <class T> |
53 | inline T make_big_value(largest_float, const char* s, boost::false_type const&, boost::false_type const&) |
54 | { |
55 | return boost::lexical_cast<T>(s); |
56 | } |
57 | #endif |
58 | template <class T> |
59 | inline BOOST_MATH_CONSTEXPR T make_big_value(largest_float, const char* s, boost::false_type const&, boost::true_type const&) BOOST_MATH_NOEXCEPT(T) |
60 | { |
61 | return T(s); |
62 | } |
63 | |
64 | // |
65 | // For constants which might fit in a long double (if it's big enough): |
66 | // |
67 | #define BOOST_MATH_BIG_CONSTANT(T, D, x)\ |
68 | boost::math::tools::make_big_value<T>(\ |
69 | BOOST_MATH_LARGEST_FLOAT_C(x), \ |
70 | BOOST_STRINGIZE(x), \ |
71 | boost::integral_constant<bool, (boost::is_convertible<boost::math::tools::largest_float, T>::value) && \ |
72 | ((D <= boost::math::tools::numeric_traits<boost::math::tools::largest_float>::digits) \ |
73 | || boost::is_floating_point<T>::value \ |
74 | || (boost::math::tools::numeric_traits<T>::is_specialized && \ |
75 | (boost::math::tools::numeric_traits<T>::digits10 <= boost::math::tools::numeric_traits<boost::math::tools::largest_float>::digits10))) >(), \ |
76 | boost::is_constructible<T, const char*>()) |
77 | // |
78 | // For constants too huge for any conceivable long double (and which generate compiler errors if we try and declare them as such): |
79 | // |
80 | #define BOOST_MATH_HUGE_CONSTANT(T, D, x)\ |
81 | boost::math::tools::make_big_value<T>(0.0L, BOOST_STRINGIZE(x), \ |
82 | boost::integral_constant<bool, boost::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)>(), \ |
83 | boost::is_constructible<T, const char*>()) |
84 | |
85 | }}} // namespaces |
86 | |
87 | #endif |
88 | |
89 | |