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

   1 //  Copyright John Maddock 2016.
   2 //  Use, modification and distribution are subject to the
   3 //  Boost Software License, Version 1.0. (See accompanying file
   4 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #ifndef BOOST_MATH_TOOLS_CONVERT_FROM_STRING_INCLUDED
   7 #define BOOST_MATH_TOOLS_CONVERT_FROM_STRING_INCLUDED
   8
   9 #ifdef _MSC_VER
  10 #pragma once
  11 #endif
  12
  13 #include <boost/type_traits/is_constructible.hpp>
  14 #include <boost/type_traits/conditional.hpp>
  15 #include <boost/lexical_cast.hpp>
  16
  17 namespace boost{ namespace math{ namespace tools{
  18
  19    template <class T>
  20    struct convert_from_string_result
  21    {
  22       typedef typename boost::conditional<boost::is_constructible<T, const char*>::value, const char*, T>::type type;
  23    };
  24
  25    template <class Real>
  26    Real convert_from_string(const char* p, const mpl::false_&)
  27    {
  28 #ifdef BOOST_MATH_NO_LEXICAL_CAST
  29       // This function should not compile, we don't have the necesary functionality to support it:
  30       BOOST_STATIC_ASSERT(sizeof(Real) == 0);
  31 #else
  32       return boost::lexical_cast<Real>(p);
  33 #endif
  34    }
  35    template <class Real>
  36    BOOST_CONSTEXPR const char* convert_from_string(const char* p, const mpl::true_&) BOOST_NOEXCEPT
  37    {
  38       return p;
  39    }
  40    template <class Real>
  41    BOOST_CONSTEXPR typename convert_from_string_result<Real>::type convert_from_string(const char* p) BOOST_NOEXCEPT_IF((boost::is_constructible<Real, const char*>::value))
  42    {
  43       return convert_from_string<Real>(p, boost::is_constructible<Real, const char*>());
  44    }
  45
  46 } // namespace tools
  47 } // namespace math
  48 } // namespace boost
  49
  50 #endif // BOOST_MATH_TOOLS_CONVERT_FROM_STRING_INCLUDED
  51