mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
synced 2024-11-14 10:39:05 +00:00
106 lines
3.1 KiB
C++
106 lines
3.1 KiB
C++
/*=============================================================================
|
||
Copyright (c) 2011-2013 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_STRLEN_HPP
|
||
#define SPROUT_CSTRING_STRLEN_HPP
|
||
|
||
#include <cstddef>
|
||
#include <iterator>
|
||
#include <type_traits>
|
||
#include <sprout/config.hpp>
|
||
#include <sprout/iterator/operation.hpp>
|
||
#include <sprout/iterator/ptr_index_iterator.hpp>
|
||
#include <sprout/utility/pair/pair.hpp>
|
||
#include <sprout/type_traits/is_char_type.hpp>
|
||
#include <sprout/algorithm/find.hpp>
|
||
|
||
namespace sprout {
|
||
namespace detail {
|
||
template<typename InputIterator>
|
||
inline SPROUT_CONSTEXPR sprout::pair<InputIterator, std::size_t>
|
||
strlen_impl_1(
|
||
sprout::pair<InputIterator, std::size_t> const& current,
|
||
typename std::iterator_traits<InputIterator>::difference_type n
|
||
)
|
||
{
|
||
typedef sprout::pair<InputIterator, std::size_t> type;
|
||
return !*current.first ? current
|
||
: n == 1 ? type(sprout::next(current.first), current.second + 1)
|
||
: sprout::detail::strlen_impl_1(
|
||
sprout::detail::strlen_impl_1(
|
||
current,
|
||
n / 2
|
||
),
|
||
n - n / 2
|
||
)
|
||
;
|
||
}
|
||
template<typename InputIterator>
|
||
inline SPROUT_CONSTEXPR sprout::pair<InputIterator, std::size_t>
|
||
strlen_impl(
|
||
sprout::pair<InputIterator, std::size_t> const& current,
|
||
typename std::iterator_traits<InputIterator>::difference_type n
|
||
)
|
||
{
|
||
return !*current.first ? current
|
||
: sprout::detail::strlen_impl(
|
||
sprout::detail::strlen_impl_1(
|
||
current,
|
||
n
|
||
),
|
||
n * 2
|
||
)
|
||
;
|
||
}
|
||
template<typename InputIterator>
|
||
inline SPROUT_CONSTEXPR std::size_t
|
||
strlen(InputIterator first) {
|
||
typedef sprout::pair<InputIterator, std::size_t> type;
|
||
return sprout::detail::strlen_impl(type(first, 0), 1).second;
|
||
}
|
||
} // namespace detail
|
||
|
||
// 7.21.6.3 strlen <20><EFBFBD>
|
||
//
|
||
// recursion depth:
|
||
// O(log N)
|
||
//
|
||
inline SPROUT_CONSTEXPR std::size_t
|
||
strlen(char const* s) {
|
||
return sprout::detail::strlen(s);
|
||
}
|
||
inline SPROUT_CONSTEXPR std::size_t
|
||
strlen(char const* s, std::size_t n) {
|
||
return sprout::distance(
|
||
sprout::ptr_index(s),
|
||
sprout::find(sprout::ptr_index(s), sprout::ptr_index(s, n), '\0')
|
||
);
|
||
}
|
||
|
||
template<typename Elem>
|
||
inline SPROUT_CONSTEXPR typename std::enable_if<
|
||
sprout::is_char_type<Elem>::value,
|
||
std::size_t
|
||
>::type
|
||
strlen(Elem* s) {
|
||
return sprout::detail::strlen(s);
|
||
}
|
||
template<typename Elem>
|
||
inline SPROUT_CONSTEXPR typename std::enable_if<
|
||
sprout::is_char_type<Elem>::value,
|
||
std::size_t
|
||
>::type
|
||
strlen(Elem* s, std::size_t n) {
|
||
typedef typename std::decay<Elem>::type type;
|
||
return sprout::distance(
|
||
sprout::ptr_index(s),
|
||
sprout::find(sprout::ptr_index(s), sprout::ptr_index(s, n), type())
|
||
);
|
||
}
|
||
} // namespace sprout
|
||
|
||
#endif // #ifndef SPROUT_CSTRING_STRLEN_HPP
|