mirror of
https://github.com/bolero-MURAKAMI/Sprout
synced 2024-12-03 21:15:42 +00:00
73 lines
2.7 KiB
C++
73 lines
2.7 KiB
C++
#ifndef SPROUT_DETAIL_ALGORITHM_LEXICOGRAPHICAL_COMPARE_HPP
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#define SPROUT_DETAIL_ALGORITHM_LEXICOGRAPHICAL_COMPARE_HPP
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#include <sprout/config.hpp>
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#include <sprout/utility/pair/pair.hpp>
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#include <sprout/iterator/next.hpp>
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namespace sprout {
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namespace detail {
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template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename Compare>
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inline SPROUT_CONSTEXPR int
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lexicographical_compare_impl_ra(
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RandomAccessIterator1 first1, RandomAccessIterator2 first2, Compare comp,
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typename std::iterator_traits<RandomAccessIterator1>::difference_type size,
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int found
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)
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{
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return found != 2 ? found
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: size == 1 ? comp(*first1, *first2) ? -1 : comp(*first2, *first1) ? 1 : 2
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: sprout::detail::lexicographical_compare_impl_ra(
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sprout::next(first1, size / 2), sprout::next(first2, size / 2), comp, size - size / 2,
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sprout::detail::lexicographical_compare_impl_ra(
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first1, first2, comp, size / 2,
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2
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)
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)
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;
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}
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template<typename InputIterator1, typename InputIterator2, typename Compare>
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inline SPROUT_CONSTEXPR sprout::pair<InputIterator1, InputIterator2>
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lexicographical_compare_impl_1(
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sprout::pair<InputIterator1, InputIterator2> const& current,
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InputIterator1 last1, InputIterator2 last2, Compare comp,
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typename std::iterator_traits<InputIterator1>::difference_type n
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)
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{
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typedef sprout::pair<InputIterator1, InputIterator2> type;
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return current.second == last2 || current.first == last1 ? current
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: n == 1 ? comp(*current.first, *current.second) ? type(last1, current.second)
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: comp(*current.second, *current.first) ? type(current.first, last2)
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: type(sprout::next(current.first), sprout::next(current.second))
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: sprout::detail::lexicographical_compare_impl_1(
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sprout::detail::lexicographical_compare_impl_1(
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current,
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last1, last2, comp, n / 2
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),
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last1, last2, comp, n - n / 2
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)
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;
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}
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template<typename InputIterator1, typename InputIterator2, typename Compare>
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inline SPROUT_CONSTEXPR sprout::pair<InputIterator1, InputIterator2>
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lexicographical_compare_impl(
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sprout::pair<InputIterator1, InputIterator2> const& current,
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InputIterator1 last1, InputIterator2 last2, Compare comp,
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typename std::iterator_traits<InputIterator1>::difference_type n
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)
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{
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return current.second == last2 || current.first == last1 ? current
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: sprout::detail::lexicographical_compare_impl(
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sprout::detail::lexicographical_compare_impl_1(
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current,
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last1, last2, comp, n
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),
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last1, last2, comp, n * 2
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)
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;
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}
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} // namespace detail
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} // namespace sprout
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#endif /* #ifndef SPROUT_DETAIL_ALGORITHM_LEXICOGRAPHICAL_COMPARE_HPP */
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