ceph/src/boost/boost/math/tools/big_constant.hpp

   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*, mpl::true_ const&, mpl::false_ 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*, mpl::true_ const&, mpl::true_ 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, mpl::false_ const&, mpl::false_ 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, mpl::false_ const&, mpl::true_ 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::mpl::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::mpl::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