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Sprout/sprout/algorithm/adjacent_find.hpp
2012-12-12 17:46:36 +09:00

101 lines
3.5 KiB
C++

#ifndef SPROUT_ALGORITHM_ADJACENT_FIND_HPP
#define SPROUT_ALGORITHM_ADJACENT_FIND_HPP
#include <iterator>
#include <sprout/config.hpp>
#include <sprout/iterator/operation.hpp>
#include HDR_FUNCTIONAL_SSCRISK_CEL_OR_SPROUT
namespace sprout {
namespace detail {
template<typename RandomAccessIterator>
inline SPROUT_CONSTEXPR RandomAccessIterator
adjacent_find_impl_ra_1(RandomAccessIterator found, RandomAccessIterator last) {
return NS_SSCRISK_CEL_OR_SPROUT::distance(found, last) == 1 ? last
: found
;
}
template<typename RandomAccessIterator, typename BinaryPredicate>
inline SPROUT_CONSTEXPR RandomAccessIterator
adjacent_find_impl_ra(
RandomAccessIterator first, RandomAccessIterator last, BinaryPredicate pred,
typename std::iterator_traits<RandomAccessIterator>::difference_type pivot, RandomAccessIterator found
)
{
return found != first ? found
: pivot == 0 ? (pred(*first, *last) ? first : last)
: sprout::detail::adjacent_find_impl_ra(
sprout::next(first, pivot), last, pred,
(NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) - pivot) / 2,
sprout::detail::adjacent_find_impl_ra(
first, sprout::next(first, pivot), pred,
pivot / 2,
first
)
)
;
}
template<typename RandomAccessIterator, typename BinaryPredicate>
inline SPROUT_CONSTEXPR RandomAccessIterator
adjacent_find(
RandomAccessIterator first, RandomAccessIterator last, BinaryPredicate pred,
std::random_access_iterator_tag*
)
{
return first == last || NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) == 1 ? last
: adjacent_find_impl_ra_1(
sprout::detail::adjacent_find_impl_ra(
first, sprout::next(first, NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) - 1), pred,
(NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) - 1) / 2, first
),
last
)
;
}
// Copyright (C) 2011 RiSK (sscrisk)
template<typename ForwardIterator, typename BinaryPredicate>
inline SPROUT_CONSTEXPR ForwardIterator
adjacent_find_impl(ForwardIterator first, ForwardIterator next, ForwardIterator last, BinaryPredicate pred) {
return next == last ? last
: pred(*first, *next) ? first
: sprout::detail::adjacent_find_impl(next, sprout::next(next), last, pred)
;
}
template<typename ForwardIterator, typename BinaryPredicate>
inline SPROUT_CONSTEXPR ForwardIterator
adjacent_find(
ForwardIterator first, ForwardIterator last, BinaryPredicate pred,
void*
)
{
return first == last ? last
: sprout::detail::adjacent_find_impl(first, sprout::next(first), last, pred)
;
}
} //namespace detail
// 25.2.8 Adjacent find
//
// recursion depth:
// [first, last) is RandomAccessIterator -> O(log N)
// otherwise -> O(N)
//
template<typename ForwardIterator, typename BinaryPredicate>
inline SPROUT_CONSTEXPR ForwardIterator
adjacent_find(ForwardIterator first, ForwardIterator last, BinaryPredicate pred) {
typedef typename std::iterator_traits<ForwardIterator>::iterator_category* category;
return sprout::detail::adjacent_find(first, last, pred, category());
}
template<typename ForwardIterator>
inline SPROUT_CONSTEXPR ForwardIterator
adjacent_find(ForwardIterator first, ForwardIterator last) {
return sprout::adjacent_find(
first, last,
NS_SSCRISK_CEL_OR_SPROUT::equal_to<typename std::iterator_traits<ForwardIterator>::value_type>()
);
}
} // namespace sprout
#endif // #ifndef SPROUT_ALGORITHM_ADJACENT_FIND_HPP