Sprout/sprout/cstring/strchr.hpp
2015-01-10 19:13:57 +09:00

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/*=============================================================================
Copyright (c) 2011-2015 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_CSTRING_STRCHR_HPP
#define SPROUT_CSTRING_STRCHR_HPP
#include <iterator>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/iterator/operation.hpp>
#include <sprout/utility/pair/pair.hpp>
#include <sprout/type_traits/is_char_type.hpp>
#include <sprout/detail/str.hpp>
namespace sprout {
namespace detail {
template<typename InputIterator, typename T>
inline SPROUT_CONSTEXPR sprout::pair<InputIterator, bool>
strchr_impl_1(
sprout::pair<InputIterator, bool> const& current,
T const& value, typename std::iterator_traits<InputIterator>::difference_type n
)
{
typedef sprout::pair<InputIterator, bool> type;
return current.second || !*current.first ? current
: n == 1 ? *current.first == value ? type(current.first, true) : type(sprout::next(current.first), false)
: sprout::detail::strchr_impl_1(
sprout::detail::strchr_impl_1(
current,
value, n / 2
),
value, n - n / 2
)
;
}
template<typename InputIterator, typename T>
inline SPROUT_CONSTEXPR sprout::pair<InputIterator, bool>
strchr_impl(
sprout::pair<InputIterator, bool> const& current,
T const& value, typename std::iterator_traits<InputIterator>::difference_type n
)
{
return current.second || !*current.first ? current
: sprout::detail::strchr_impl(
sprout::detail::strchr_impl_1(
current,
value, n
),
value, n * 2
)
;
}
template<typename InputIterator, typename T>
inline SPROUT_CONSTEXPR InputIterator
strchr(InputIterator first, T const& value) {
typedef sprout::pair<InputIterator, bool> type;
return sprout::detail::strchr_impl(type(first, false), value, 1).first;
}
} // namespace detail
// 7.21.5.2 strchr <20>֐<EFBFBD>
//
// recursion depth:
// O(log N)
//
inline SPROUT_CONSTEXPR char const*
strchr(char const* s, int c) {
return sprout::detail::str_find_check(
sprout::detail::strchr(s, static_cast<char>(c)),
static_cast<char>(c)
);
}
inline SPROUT_CONSTEXPR char*
strchr(char* s, int c) {
return sprout::detail::str_find_check(
sprout::detail::strchr(s, static_cast<char>(c)),
static_cast<char>(c)
);
}
template<typename Elem>
inline SPROUT_CONSTEXPR typename std::enable_if<
sprout::is_char_type<Elem>::value,
Elem*
>::type
strchr(Elem* s, typename std::decay<Elem>::type c) {
return sprout::detail::str_find_check(
sprout::detail::strchr(s, c),
c
);
}
} // namespace sprout
#endif // #ifndef SPROUT_CSTRING_STRCHR_HPP