ceph/src/boost/libs/math/include/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_convertible.hpp>
  15
  16 namespace boost{ namespace math{
  17
  18 namespace tools{
  19
  20 template <class T>
  21 struct numeric_traits : public std::numeric_limits< T > {};
  22
  23 #ifdef BOOST_MATH_USE_FLOAT128
  24 typedef __float128 largest_float;
  25 #define BOOST_MATH_LARGEST_FLOAT_C(x) x##Q
  26 template <>
  27 struct numeric_traits<__float128>
  28 {
  29    static const int digits = 113;
  30    static const int digits10 = 33;
  31    static const int max_exponent = 16384;
  32    static const bool is_specialized = true;
  33 };
  34 #else
  35 typedef long double largest_float;
  36 #define BOOST_MATH_LARGEST_FLOAT_C(x) x##L
  37 #endif
  38
  39 template <class T>
  40 inline BOOST_CONSTEXPR_OR_CONST T make_big_value(largest_float v, const char*, mpl::true_ const&, mpl::false_ const&) BOOST_MATH_NOEXCEPT(T)
  41 {
  42    return static_cast<T>(v);
  43 }
  44 template <class T>
  45 inline BOOST_CONSTEXPR_OR_CONST T make_big_value(largest_float v, const char*, mpl::true_ const&, mpl::true_ const&) BOOST_MATH_NOEXCEPT(T)
  46 {
  47    return static_cast<T>(v);
  48 }
  49 #ifndef BOOST_MATH_NO_LEXICAL_CAST
  50 template <class T>
  51 inline T make_big_value(largest_float, const char* s, mpl::false_ const&, mpl::false_ const&)
  52 {
  53    return boost::lexical_cast<T>(s);
  54 }
  55 #endif
  56 template <class T>
  57 inline BOOST_MATH_CONSTEXPR const char* make_big_value(largest_float, const char* s, mpl::false_ const&, mpl::true_ const&) BOOST_MATH_NOEXCEPT(T)
  58 {
  59    return s;
  60 }
  61
  62 //
  63 // For constants which might fit in a long double (if it's big enough):
  64 //
  65 #define BOOST_MATH_BIG_CONSTANT(T, D, x)\
  66    boost::math::tools::make_big_value<T>(\
  67       BOOST_MATH_LARGEST_FLOAT_C(x), \
  68       BOOST_STRINGIZE(x), \
  69       mpl::bool_< (is_convertible<boost::math::tools::largest_float, T>::value) && \
  70       ((D <= boost::math::tools::numeric_traits<boost::math::tools::largest_float>::digits) \
  71           || is_floating_point<T>::value \
  72           || (boost::math::tools::numeric_traits<T>::is_specialized && \
  73           (boost::math::tools::numeric_traits<T>::digits10 <= boost::math::tools::numeric_traits<boost::math::tools::largest_float>::digits10))) >(), \
  74       boost::is_convertible<const char*, T>())
  75 //
  76 // For constants too huge for any conceivable long double (and which generate compiler errors if we try and declare them as such):
  77 //
  78 #define BOOST_MATH_HUGE_CONSTANT(T, D, x)\
  79    boost::math::tools::make_big_value<T>(0.0L, BOOST_STRINGIZE(x), \
  80    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)>(), \
  81    boost::is_convertible<const char*, T>())
  82
  83 }}} // namespaces
  84
  85 #endif
  86