Added thirdparty: boost library

thirdparty/include/boost/math/tools/convert_from_string.hpp

@@ -0,0 +1,74 @@
+//  Copyright John Maddock 2016.
+//  Copyright Matt Borland 2023.
+//  Use, modification and distribution are subject to the
+//  Boost Software License, Version 1.0. (See accompanying file
+//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_MATH_TOOLS_CONVERT_FROM_STRING_INCLUDED
+#define BOOST_MATH_TOOLS_CONVERT_FROM_STRING_INCLUDED
+
+#ifdef _MSC_VER
+#pragma once
+#endif
+
+#include <boost/math/tools/config.hpp>
+#include <type_traits>
+#ifndef BOOST_MATH_STANDALONE
+#include <boost/lexical_cast.hpp>
+#endif
+
+namespace boost{ namespace math{ namespace tools{
+
+   template <class T>
+   struct convert_from_string_result
+   {
+      typedef typename std::conditional<std::is_constructible<T, const char*>::value, const char*, T>::type type;
+   };
+
+   template <class Real>
+   Real convert_from_string(const char* p, const std::false_type&)
+   {
+      #ifdef BOOST_MATH_NO_LEXICAL_CAST
+
+      // This function should not compile, we don't have the necessary functionality to support it:
+      static_assert(sizeof(Real) == 0, "boost.lexical_cast is not supported in standalone mode.");
+      (void)p; // Suppresses -Wunused-parameter
+      return Real(0);
+
+      #elif defined(BOOST_MATH_USE_CHARCONV_FOR_CONVERSION)
+
+      if constexpr (std::is_arithmetic_v<Real>)
+      {
+         Real v {};
+         std::from_chars(p, p + std::strlen(p), v);
+
+         return v;
+      }
+      else
+      {
+         return boost::lexical_cast<Real>(p);
+      }
+
+      #else
+
+      return boost::lexical_cast<Real>(p);
+
+      #endif
+   }
+   template <class Real>
+   constexpr const char* convert_from_string(const char* p, const std::true_type&) noexcept
+   {
+      return p;
+   }
+   template <class Real>
+   constexpr typename convert_from_string_result<Real>::type convert_from_string(const char* p) noexcept((std::is_constructible<Real, const char*>::value))
+   {
+      return convert_from_string<Real>(p, std::is_constructible<Real, const char*>());
+   }
+
+} // namespace tools
+} // namespace math
+} // namespace boost
+
+#endif // BOOST_MATH_TOOLS_CONVERT_FROM_STRING_INCLUDED
+