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Sprout/sprout/algorithm/any_of_equal.hpp
2013-01-03 17:01:50 +09:00

73 lines
2.2 KiB
C++

#ifndef SPROUT_ALGORITHM_ANY_OF_EQUAL_HPP
#define SPROUT_ALGORITHM_ANY_OF_EQUAL_HPP
#include <iterator>
#include <sprout/config.hpp>
#include <sprout/iterator/operation.hpp>
namespace sprout {
namespace detail {
template<typename RandomAccessIterator, typename T>
inline SPROUT_CONSTEXPR bool
any_of_equal_impl_ra(
RandomAccessIterator first, RandomAccessIterator last, T const& value,
typename std::iterator_traits<RandomAccessIterator>::difference_type pivot
)
{
return pivot == 0 ? *first == value
: sprout::detail::any_of_equal_impl_ra(
first, sprout::next(first, pivot), value,
pivot / 2
)
|| sprout::detail::any_of_equal_impl_ra(
sprout::next(first, pivot), last, value,
(sprout::distance(first, last) - pivot) / 2
)
;
}
template<typename RandomAccessIterator, typename T>
inline SPROUT_CONSTEXPR bool
any_of_equal(
RandomAccessIterator first, RandomAccessIterator last, T const& value,
std::random_access_iterator_tag*
)
{
return first == last ? false
: sprout::detail::any_of_equal_impl_ra(first, last, value, sprout::distance(first, last) / 2)
;
}
template<typename InputIterator, typename T>
inline SPROUT_CONSTEXPR bool
any_of_equal_impl(InputIterator first, InputIterator last, T const& value) {
return first == last ? false
: *first == value || sprout::detail::any_of_equal_impl(sprout::next(first), last, value)
;
}
template<typename InputIterator, typename T>
inline SPROUT_CONSTEXPR bool
any_of_equal(
InputIterator first, InputIterator last, T const& value,
void*
)
{
return sprout::detail::any_of_equal_impl(first, last, value);
}
} //namespace detail
//
// any_of_equal
//
// recursion depth:
// [first, last) is RandomAccessIterator -> O(log N)
// otherwise -> O(N)
//
template<typename InputIterator, typename T>
inline SPROUT_CONSTEXPR bool
any_of_equal(InputIterator first, InputIterator last, T const& value) {
typedef typename std::iterator_traits<InputIterator>::iterator_category* category;
return sprout::detail::any_of_equal(first, last, value, category());
}
} // namespace sprout
#endif // #ifndef SPROUT_ALGORITHM_ANY_OF_EQUAL_HPP