Sprout/sprout/cstdlib/ascii_to_int.hpp
2016-02-25 18:48:28 +09:00

87 lines
3.5 KiB
C++

/*=============================================================================
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_CSTDLIB_DECIMAL_TO_INT_HPP
#define SPROUT_CSTDLIB_DECIMAL_TO_INT_HPP
#include <iterator>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/limits.hpp>
#include <sprout/type_traits/is_signed.hpp>
#include <sprout/type_traits/is_unsigned.hpp>
#include <sprout/iterator/operation.hpp>
#include <sprout/ctype/ascii.hpp>
#include <sprout/detail/char_literal.hpp>
#include <sprout/detail/char_type_of_consecutive.hpp>
namespace sprout {
namespace detail {
// Copyright (c) 2011 osyo-manga : http://d.hatena.ne.jp/osyo-manga/
template<typename IntType, typename NullTerminatedIterator>
inline SPROUT_CONSTEXPR IntType
ascii_to_int_impl(NullTerminatedIterator str, IntType val, bool negative) {
typedef typename std::iterator_traits<NullTerminatedIterator>::value_type value_type;
SPROUT_STATIC_ASSERT(sprout::detail::is_char_type_of_consecutive_digits<value_type>::value);
return !sprout::ascii::isdigit(*str)
? negative ? -val : val
: val > (sprout::numeric_limits<IntType>::max() - (*str - SPROUT_CHAR_LITERAL('0', value_type)) - (negative ? 1 : 0)) / 10
? (negative ? sprout::numeric_limits<IntType>::min() : sprout::numeric_limits<IntType>::max())
: sprout::detail::ascii_to_int_impl<IntType>(
sprout::next(str),
val * 10 + (*str - SPROUT_CHAR_LITERAL('0', value_type)),
negative
)
;
}
template<typename IntType, typename NullTerminatedIterator>
inline SPROUT_CONSTEXPR typename std::enable_if<
sprout::is_unsigned<IntType>::value,
IntType
>::type
ascii_to_int(NullTerminatedIterator str) {
typedef typename std::iterator_traits<NullTerminatedIterator>::value_type value_type;
return sprout::ascii::isspace(*str)
? sprout::detail::ascii_to_int<IntType>(sprout::next(str))
: *str == SPROUT_CHAR_LITERAL('+', value_type)
? sprout::detail::ascii_to_int_impl<IntType>(sprout::next(str), IntType(), false)
: sprout::detail::ascii_to_int_impl<IntType>(str, IntType(), false)
;
}
template<typename IntType, typename NullTerminatedIterator>
inline SPROUT_CONSTEXPR typename std::enable_if<
sprout::is_signed<IntType>::value,
IntType
>::type
ascii_to_int(NullTerminatedIterator str) {
typedef typename std::iterator_traits<NullTerminatedIterator>::value_type value_type;
return sprout::ascii::isspace(*str)
? sprout::detail::ascii_to_int<IntType>(sprout::next(str))
: *str == SPROUT_CHAR_LITERAL('-', value_type)
? sprout::detail::ascii_to_int_impl<IntType>(sprout::next(str), IntType(), true)
: *str == SPROUT_CHAR_LITERAL('+', value_type)
? sprout::detail::ascii_to_int_impl<IntType>(sprout::next(str), IntType(), false)
: sprout::detail::ascii_to_int_impl<IntType>(str, IntType(), false)
;
}
} // namespace detail
//
// ascii_to_int
//
template<typename IntType, typename Char>
inline SPROUT_CONSTEXPR typename std::enable_if<
std::is_integral<IntType>::value,
IntType
>::type
ascii_to_int(Char const* str) {
return sprout::detail::ascii_to_int<IntType>(str);
}
} // namespace sprout
#endif // #ifndef SPROUT_CSTDLIB_DECIMAL_TO_INT_HPP