Sprout/sprout/detail/char_conversion.hpp

#ifndef SPROUT_DETAIL_CHAR_CONVERSION_HPP
#define SPROUT_DETAIL_CHAR_CONVERSION_HPP

#include <cstddef>
#include <stdexcept>
#include <sprout/config.hpp>
#include <sprout/ctype/ascii.hpp>

namespace sprout {
	namespace detail {
		template<typename Elem, typename IntType>
		inline SPROUT_CONSTEXPR Elem int_to_char(IntType val, std::size_t base){
			return val >= 0 && val < 10 ? static_cast<Elem>('0') + val
				: val >= 10 && val < base ? static_cast<Elem>('a') + (val - 10)
				: throw std::invalid_argument("value out of bounds")
				;
		}
		template<typename Elem, typename IntType>
		inline SPROUT_CONSTEXPR Elem int_to_char(IntType val){
			return val >= 0 && val < 10 ? static_cast<Elem>('0') + val
				: throw std::invalid_argument("value out of bounds")
				;
		}

		template<typename IntType, typename Elem>
		inline SPROUT_CONSTEXPR IntType char_to_int(Elem c, std::size_t base){
			return sprout::ascii::isdigit(c) && static_cast<std::size_t>(c - static_cast<Elem>('0')) < base ? c - static_cast<Elem>('0')
				: sprout::ascii::islower(c) && static_cast<std::size_t>(c - static_cast<Elem>('a') + 10) < base ? c - static_cast<Elem>('a') + 10
				: sprout::ascii::isupper(c) && static_cast<std::size_t>(c - static_cast<Elem>('A') + 10) < base ? c - static_cast<Elem>('A') + 10
				: static_cast<IntType>(-1)
				;
		}
		template<typename IntType, typename Elem>
		inline SPROUT_CONSTEXPR IntType char_to_int(Elem c){
			return sprout::ascii::isdigit(c) ? c - static_cast<Elem>('0')
				: static_cast<IntType>(-1)
				;
		}
	}	// namespace detail
}	// namespace sprout

#endif	// #ifndef SPROUT_DETAIL_CHAR_CONVERSION_HPP