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
17namespace 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 boost::false_type&)
27 {
28#ifdef BOOST_MATH_NO_LEXICAL_CAST
29 // This function should not compile, we don't have the necessary 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 boost::true_type&) 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
52

source code of include/boost/math/tools/convert_from_string.hpp