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_STANDALONE
  12 #include <boost/lexical_cast.hpp>
  13 #endif
  14
  15 #include <cstdlib>
  16 #include <type_traits>
  17 #include <limits>
  18
  19 namespace boost{ namespace math{
  20
  21 namespace tools{
  22
  23 template <class T>
  24 struct numeric_traits : public std::numeric_limits< T > {};
  25
  26 #ifdef BOOST_MATH_USE_FLOAT128
  27 typedef __float128 largest_float;
  28 #define BOOST_MATH_LARGEST_FLOAT_C(x) x##Q
  29 template <>
  30 struct numeric_traits<__float128>
  31 {
  32    static const int digits = 113;
  33    static const int digits10 = 33;
  34    static const int max_exponent = 16384;
  35    static const bool is_specialized = true;
  36 };
  37 #elif LDBL_DIG > DBL_DIG
  38 typedef long double largest_float;
  39 #define BOOST_MATH_LARGEST_FLOAT_C(x) x##L
  40 #else
  41 typedef double largest_float;
  42 #define BOOST_MATH_LARGEST_FLOAT_C(x) x
  43 #endif
  44
  45 template <class T>
  46 inline constexpr T make_big_value(largest_float v, const char*, std::true_type const&, std::false_type const&) BOOST_MATH_NOEXCEPT(T)
  47 {
  48    return static_cast<T>(v);
  49 }
  50 template <class T>
  51 inline constexpr T make_big_value(largest_float v, const char*, std::true_type const&, std::true_type const&) BOOST_MATH_NOEXCEPT(T)
  52 {
  53    return static_cast<T>(v);
  54 }
  55 #ifndef BOOST_MATH_NO_LEXICAL_CAST
  56 template <class T>
  57 inline T make_big_value(largest_float, const char* s, std::false_type const&, std::false_type const&)
  58 {
  59    return boost::lexical_cast<T>(s);
  60 }
  61 #else
  62 template <typename T>
  63 inline T make_big_value(largest_float, const char* s, std::false_type const&, std::false_type const&)
  64 {
  65    static_assert(sizeof(T) == 0, "Type is unsupported in standalone mode. Please disable and try again.");
  66 }
  67 #endif
  68 template <class T>
  69 inline constexpr T make_big_value(largest_float, const char* s, std::false_type const&, std::true_type const&) BOOST_MATH_NOEXCEPT(T)
  70 {
  71    return T(s);
  72 }
  73
  74 //
  75 // For constants which might fit in a long double (if it's big enough):
  76 //
  77 #define BOOST_MATH_BIG_CONSTANT(T, D, x)\
  78    boost::math::tools::make_big_value<T>(\
  79       BOOST_MATH_LARGEST_FLOAT_C(x), \
  80       BOOST_STRINGIZE(x), \
  81       std::integral_constant<bool, (std::is_convertible<boost::math::tools::largest_float, T>::value) && \
  82       ((D <= boost::math::tools::numeric_traits<boost::math::tools::largest_float>::digits) \
  83           || std::is_floating_point<T>::value \
  84           || (boost::math::tools::numeric_traits<T>::is_specialized && \
  85           (boost::math::tools::numeric_traits<T>::digits10 <= boost::math::tools::numeric_traits<boost::math::tools::largest_float>::digits10))) >(), \
  86       std::is_constructible<T, const char*>())
  87 //
  88 // For constants too huge for any conceivable long double (and which generate compiler errors if we try and declare them as such):
  89 //
  90 #define BOOST_MATH_HUGE_CONSTANT(T, D, x)\
  91    boost::math::tools::make_big_value<T>(0.0L, BOOST_STRINGIZE(x), \
  92    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)>(), \
  93    std::is_constructible<T, const char*>())
  94
  95 }}} // namespaces
  96
  97 #endif
  98