Sprout/sprout/utility/string_view/string_to_float.hpp

/*=============================================================================
  Copyright (c) 2011-2016 Bolero MURAKAMI
  https://github.com/bolero-MURAKAMI/Sprout

  Distributed under 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 SPROUT_UTILITY_STRING_VIEW_STRING_TO_FLOAT_HPP
#define SPROUT_UTILITY_STRING_VIEW_STRING_TO_FLOAT_HPP

#include <string>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/utility/string_view/string_view.hpp>
#include <sprout/cstdlib/str_to_float.hpp>
#include <sprout/type_traits/enabler_if.hpp>

namespace sprout {
	namespace detail {
		template<
			typename FloatType, typename Elem, typename Traits
		>
		inline FloatType string_to_float_dynamic(sprout::basic_string_view<Elem, Traits> const& str, std::size_t* idx) {
			Elem* endptr = nullptr;
			FloatType result = sprout::detail::str_to_float<FloatType>(str.c_str(), &endptr);
			*idx = endptr - str.c_str();
			return result;
		}
	}

	//
	// string_to_float
	//
	template<
		typename FloatType, typename Elem, typename Traits,
		typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
	>
	inline SPROUT_CONSTEXPR FloatType
	string_to_float(sprout::basic_string_view<Elem, Traits> const& str, std::size_t* idx) {
		return !idx ? sprout::detail::str_to_float<FloatType>(str.begin())
			: sprout::detail::string_to_float_dynamic<FloatType>(str, idx)
			;
	}
	template<
		typename FloatType, typename Elem, typename Traits,
		typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
	>
	inline SPROUT_CONSTEXPR FloatType
	string_to_float(sprout::basic_string_view<Elem, Traits> const& str) {
		return sprout::detail::str_to_float<FloatType>(str.begin());
	}

	//
	// stof
	//
	template<typename Elem, typename Traits>
	inline SPROUT_CONSTEXPR float
	stof(sprout::basic_string_view<Elem, Traits> const& str, std::size_t* idx) {
		return sprout::string_to_float<float>(str, idx);
	}
	template<typename Elem, typename Traits>
	inline SPROUT_CONSTEXPR float
	stof(sprout::basic_string_view<Elem, Traits> const& str) {
		return sprout::string_to_float<float>(str);
	}

	//
	// stod
	//
	template<typename Elem, typename Traits>
	inline SPROUT_CONSTEXPR double
	stod(sprout::basic_string_view<Elem, Traits> const& str, std::size_t* idx) {
		return sprout::string_to_float<double>(str, idx);
	}
	template<typename Elem, typename Traits>
	inline SPROUT_CONSTEXPR double
	stod(sprout::basic_string_view<Elem, Traits> const& str) {
		return sprout::string_to_float<double>(str);
	}

	//
	// stold
	//
	template<typename Elem, typename Traits>
	inline SPROUT_CONSTEXPR long double
	stold(sprout::basic_string_view<Elem, Traits> const& str, std::size_t* idx) {
		return sprout::string_to_float<long double>(str, idx);
	}
	template<typename Elem, typename Traits>
	inline SPROUT_CONSTEXPR long double
	stold(sprout::basic_string_view<Elem, Traits> const& str) {
		return sprout::string_to_float<long double>(str);
	}

	//
	// from_string
	//
	template<
		typename FloatType, typename Elem, typename Traits,
		typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
	>
	inline SPROUT_CONSTEXPR FloatType
	from_string(sprout::basic_string_view<Elem, Traits> const& str, std::size_t* idx) {
		return sprout::string_to_float<FloatType>(str, idx);
	}
	template<
		typename FloatType, typename Elem, typename Traits,
		typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
	>
	inline SPROUT_CONSTEXPR FloatType
	from_string(sprout::basic_string_view<Elem, Traits> const& str) {
		return sprout::string_to_float<FloatType>(str);
	}
}	// namespace sprout

#endif	// #ifndef SPROUT_UTILITY_STRING_VIEW_STRING_TO_FLOAT_HPP