mirror of
https://github.com/bolero-MURAKAMI/Sprout
synced 2024-11-12 21:09:01 +00:00
76 lines
2.5 KiB
C++
76 lines
2.5 KiB
C++
/*=============================================================================
|
|
Copyright (c) 2011 RiSK (sscrisk)
|
|
https://github.com/sscrisk/CEL---ConstExpr-Library
|
|
|
|
Copyright (c) 2011-2017 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_ALGORITHM_PARTITION_POINT_HPP
|
|
#define SPROUT_ALGORITHM_PARTITION_POINT_HPP
|
|
|
|
#include <iterator>
|
|
#include <sprout/config.hpp>
|
|
#include <sprout/detail/predef.hpp>
|
|
#include <sprout/iterator/operation.hpp>
|
|
|
|
namespace sprout {
|
|
#if defined(SPROUT_CONFIG_DISABLE_CXX14_CONSTEXPR) || SPROUT_GCC_IN_RANGE((5, 1, 0), (6, 0, 0))
|
|
namespace detail {
|
|
template<typename ForwardIterator, typename Predicate>
|
|
inline SPROUT_CONSTEXPR ForwardIterator
|
|
partition_point_impl(ForwardIterator const& first, ForwardIterator const& last, Predicate pred, ForwardIterator const& mid) {
|
|
return mid == last ? mid
|
|
: pred(*mid) ? sprout::detail::partition_point_impl(
|
|
sprout::next(mid), last, pred,
|
|
sprout::next(mid, 1 + (sprout::distance(mid, last) - 1) / 2)
|
|
)
|
|
: sprout::detail::partition_point_impl(
|
|
first, mid, pred,
|
|
sprout::next(first, sprout::distance(first, mid) / 2)
|
|
)
|
|
;
|
|
}
|
|
} // namespace detail
|
|
|
|
// 25.3.13 Partitions
|
|
//
|
|
// recursion depth:
|
|
// O(log N)
|
|
//
|
|
template<typename ForwardIterator, typename Predicate>
|
|
inline SPROUT_CONSTEXPR ForwardIterator
|
|
partition_point(ForwardIterator first, ForwardIterator last, Predicate pred) {
|
|
return sprout::detail::partition_point_impl(
|
|
first, last, pred,
|
|
sprout::next(first, sprout::distance(first, last) / 2)
|
|
);
|
|
}
|
|
#else
|
|
// 25.3.13 Partitions
|
|
//
|
|
// recursion depth:
|
|
// 0
|
|
//
|
|
template<typename ForwardIterator, typename Predicate>
|
|
inline SPROUT_CXX14_CONSTEXPR ForwardIterator
|
|
partition_point(ForwardIterator first, ForwardIterator last, Predicate pred) {
|
|
typedef typename std::iterator_traits<ForwardIterator>::difference_type difference_type;
|
|
for (difference_type len = sprout::distance(first, last); len != 0; ) {
|
|
difference_type const half = len / 2;
|
|
ForwardIterator const mid = sprout::next(first, half);
|
|
if (pred(*mid)) {
|
|
first = sprout::next(mid);
|
|
len -= half + 1;
|
|
} else {
|
|
len = half;
|
|
}
|
|
}
|
|
return first;
|
|
}
|
|
#endif
|
|
} // namespace sprout
|
|
|
|
#endif // #ifndef SPROUT_ALGORITHM_PARTITION_POINT_HPP
|