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Sprout/sprout/algorithm/find_if_not.hpp
2013-01-11 02:55:19 +09:00

110 lines
3.6 KiB
C++

#ifndef SPROUT_ALGORITHM_FIND_IF_NOT_HPP
#define SPROUT_ALGORITHM_FIND_IF_NOT_HPP
#include <iterator>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/iterator/operation.hpp>
#include <sprout/iterator/type_traits/is_iterator.hpp>
#include <sprout/utility/pair.hpp>
namespace sprout {
namespace detail {
template<typename RandomAccessIterator, typename Predicate>
inline SPROUT_CONSTEXPR RandomAccessIterator
find_if_not_impl_ra(
RandomAccessIterator first, RandomAccessIterator last, Predicate pred,
typename std::iterator_traits<RandomAccessIterator>::difference_type pivot, RandomAccessIterator found
)
{
return found != first ? found
: pivot == 0 ? (!pred(*first) ? first : last)
: sprout::detail::find_if_not_impl_ra(
sprout::next(first, pivot), last, pred,
(sprout::distance(first, last) - pivot) / 2,
sprout::detail::find_if_not_impl_ra(
first, sprout::next(first, pivot), pred,
pivot / 2,
first
)
)
;
}
template<typename RandomAccessIterator, typename Predicate>
inline SPROUT_CONSTEXPR typename std::enable_if<
sprout::is_constant_distance_iterator<RandomAccessIterator>::value,
RandomAccessIterator
>::type
find_if_not(
RandomAccessIterator first, RandomAccessIterator last, Predicate pred,
std::random_access_iterator_tag*
)
{
return first == last ? last
: sprout::detail::find_if_not_impl_ra(first, last, pred, sprout::distance(first, last) / 2, first)
;
}
template<typename InputIterator, typename Predicate>
inline SPROUT_CONSTEXPR sprout::pair<InputIterator, bool>
find_if_not_impl_1(
sprout::pair<InputIterator, bool> const& current,
InputIterator last, Predicate pred, typename std::iterator_traits<InputIterator>::difference_type n
)
{
typedef sprout::pair<InputIterator, bool> type;
return current.second || current.first == last ? current
: n == 1 ? !pred(*current.first) ? type(current.first, true) : type(sprout::next(current.first), false)
: sprout::detail::find_if_not_impl_1(
sprout::detail::find_if_not_impl_1(
current,
last, pred, n / 2
),
last, pred, n - n / 2
)
;
}
template<typename InputIterator, typename Predicate>
inline SPROUT_CONSTEXPR sprout::pair<InputIterator, bool>
find_if_not_impl(
sprout::pair<InputIterator, bool> const& current,
InputIterator last, Predicate pred, typename std::iterator_traits<InputIterator>::difference_type n
)
{
typedef sprout::pair<InputIterator, bool> type;
return current.second || current.first == last ? current
: sprout::detail::find_if_not_impl(
sprout::detail::find_if_not_impl_1(
current,
last, pred, n
),
last, pred, n * 2
)
;
}
template<typename InputIterator, typename Predicate>
inline SPROUT_CONSTEXPR InputIterator
find_if_not(
InputIterator first, InputIterator last, Predicate pred,
void*
)
{
typedef sprout::pair<InputIterator, bool> type;
return sprout::detail::find_if_not_impl(type(first, false), last, pred, 1).first;
}
} // namespace detail
// 25.2.5 Find
//
// recursion depth:
// O(log N)
//
template<typename InputIterator, typename Predicate>
inline SPROUT_CONSTEXPR InputIterator
find_if_not(InputIterator first, InputIterator last, Predicate pred) {
typedef typename std::iterator_traits<InputIterator>::iterator_category* category;
return sprout::detail::find_if_not(first, last, pred, category());
}
} // namespace sprout
#endif // #ifndef SPROUT_ALGORITHM_FIND_IF_NOT_HPP