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

76 lines
2.5 KiB
C++

#ifndef SPROUT_ALGORITHM_FIND_IF_HPP
#define SPROUT_ALGORITHM_FIND_IF_HPP
#include <iterator>
#include <sprout/config.hpp>
#include <sprout/iterator/operation.hpp>
#include HDR_ITERATOR_SSCRISK_CEL_OR_SPROUT
namespace sprout {
namespace detail {
template<typename RandomAccessIterator, typename Predicate>
inline SPROUT_CONSTEXPR RandomAccessIterator
find_if_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_impl_ra(
sprout::next(first, pivot), last, pred,
(NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) - pivot) / 2,
sprout::detail::find_if_impl_ra(
first, sprout::next(first, pivot), pred,
pivot / 2,
first
)
)
;
}
template<typename RandomAccessIterator, typename Predicate>
inline SPROUT_CONSTEXPR RandomAccessIterator
find_if(
RandomAccessIterator first, RandomAccessIterator last, Predicate pred,
std::random_access_iterator_tag*
)
{
return first == last ? last
: sprout::detail::find_if_impl_ra(first, last, pred, NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) / 2, first)
;
}
// Copyright (C) 2011 RiSK (sscrisk)
template<typename InputIterator, typename Predicate>
inline SPROUT_CONSTEXPR InputIterator
find_if_impl(InputIterator first, InputIterator last, Predicate pred) {
return first == last || pred(*first) ? first
: sprout::detail::find_if_impl(sprout::next(first), last, pred)
;
}
template<typename InputIterator, typename Predicate>
inline SPROUT_CONSTEXPR InputIterator
find_if(
InputIterator first, InputIterator last, Predicate pred,
void*
)
{
return sprout::detail::find_if_impl(first, last, pred);
}
} //namespace detail
// 25.2.5 Find
//
// recursion depth:
// [first, last) is RandomAccessIterator -> O(log N)
// otherwise -> O(N)
//
template<typename InputIterator, typename Predicate>
inline SPROUT_CONSTEXPR InputIterator
find_if(InputIterator first, InputIterator last, Predicate pred) {
typedef typename std::iterator_traits<InputIterator>::iterator_category* category;
return sprout::detail::find_if(first, last, pred, category());
}
} // namespace sprout
#endif // #ifndef SPROUT_ALGORITHM_FIND_IF_HPP