mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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249 lines
8.1 KiB
C++
249 lines
8.1 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2013 Bolero MURAKAMI
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https://github.com/bolero-MURAKAMI/Sprout
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef SPROUT_ITERATOR_MERGE_ITERATOR_HPP
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#define SPROUT_ITERATOR_MERGE_ITERATOR_HPP
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#include <iterator>
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#include <utility>
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#include <type_traits>
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#include <sprout/config.hpp>
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#include <sprout/iterator/next.hpp>
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#include <sprout/iterator/type_traits/common.hpp>
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#include <sprout/functional/less.hpp>
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#include <sprout/utility/swap.hpp>
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namespace sprout {
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//
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// merge_iterator
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//
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template<
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typename LIterator, typename RIterator,
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typename Compare = sprout::less<>
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>
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class merge_iterator
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: public std::iterator<
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typename sprout::min_iterator_category<
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typename sprout::common_iterator_category<LIterator, RIterator>::type,
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std::forward_iterator_tag
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>::type,
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typename sprout::common_iterator_value_type<LIterator, RIterator>::type,
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typename sprout::common_iterator_difference_type<LIterator, RIterator>::type,
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typename sprout::common_iterator_pointer<LIterator, RIterator>::type,
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typename sprout::common_iterator_reference<LIterator, RIterator>::type
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>
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{
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public:
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typedef LIterator iterator_type;
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typedef RIterator iterator2_type;
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typedef Compare compare_type;
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typedef typename sprout::min_iterator_category<
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typename sprout::common_iterator_category<LIterator, RIterator>::type,
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std::forward_iterator_tag
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>::type iterator_category;
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typedef typename sprout::common_iterator_value_type<LIterator, RIterator>::type value_type;
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typedef typename sprout::common_iterator_difference_type<LIterator, RIterator>::type difference_type;
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typedef typename sprout::common_iterator_pointer<LIterator, RIterator>::type pointer;
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typedef typename sprout::common_iterator_reference<LIterator, RIterator>::type reference;
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private:
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static SPROUT_CONSTEXPR bool check_in_left(
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iterator_type it1, iterator_type lst1,
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iterator2_type it2, iterator2_type lst2,
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Compare comp
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)
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{
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return it1 != lst1 ? (it2 != lst2 ? !comp(*it2, *it1) : true)
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: !(it2 != lst2)
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;
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}
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protected:
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iterator_type current1;
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iterator_type lst1;
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iterator2_type current2;
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iterator2_type lst2;
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Compare comp;
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bool in_left;
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public:
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SPROUT_CONSTEXPR merge_iterator()
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: current1(), lst1(), current2(), lst2(), comp(), in_left(true)
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{}
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merge_iterator(merge_iterator const&) = default;
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SPROUT_CONSTEXPR merge_iterator(
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iterator_type it1, iterator_type lst1,
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iterator2_type it2, iterator2_type lst2,
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Compare comp = Compare()
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)
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: current1(it1), lst1(lst1)
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, current2(it2), lst2(lst2)
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, comp(comp)
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, in_left(check_in_left(it1, lst1, it2, lst2, comp))
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{}
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template<typename U, typename V, typename W>
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SPROUT_CONSTEXPR merge_iterator(merge_iterator<U, V, W> const& it)
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: current1(it.base()), lst1(it.last1())
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, current2(it.base2()), lst2(it.last2())
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, comp(it.compare())
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, in_left(it.is_in_left())
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{}
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template<typename U, typename V, typename W>
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SPROUT_CXX14_CONSTEXPR merge_iterator& operator=(merge_iterator<U, V, W> const& it) {
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merge_iterator temp(it);
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temp.swap(*this);
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return *this;
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}
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SPROUT_CONSTEXPR iterator_type base() const {
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return current1;
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}
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SPROUT_CONSTEXPR iterator_type last1() const {
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return lst1;
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}
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SPROUT_CONSTEXPR iterator2_type base2() const {
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return current2;
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}
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SPROUT_CONSTEXPR iterator2_type last2() const {
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return lst2;
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}
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SPROUT_CONSTEXPR Compare compare() const {
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return comp;
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}
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SPROUT_CONSTEXPR bool is_in_left() const {
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return in_left;
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}
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SPROUT_CONSTEXPR reference operator*() const {
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return is_in_left() ? *current1 : *current2;
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}
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SPROUT_CONSTEXPR pointer operator->() const {
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return &*(*this);
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}
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SPROUT_CXX14_CONSTEXPR merge_iterator& operator++() {
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if (current1 != lst1) {
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if (current2 != lst2) {
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if (comp(*current2, *current1)) {
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++current2;
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} else {
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++current1;
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}
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} else {
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++current1;
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}
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} else if (current2 != lst2) {
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++current2;
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}
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in_left = check_in_left(current1, lst1, current2, lst2, comp);
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return *this;
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}
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SPROUT_CXX14_CONSTEXPR merge_iterator operator++(int) {
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merge_iterator result(*this);
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if (current1 != lst1) {
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if (current2 != lst2) {
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if (comp(*current2, *current1)) {
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++current2;
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} else {
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++current1;
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}
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} else {
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++current1;
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}
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} else if (current2 != lst2) {
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++current2;
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}
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in_left = check_in_left(current1, lst1, current2, lst2, comp);
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return result;
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}
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SPROUT_CONSTEXPR merge_iterator next() const {
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return current1 != lst1
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? current2 != lst2
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? comp(*current2, *current1)
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? merge_iterator(current1, lst1, sprout::next(current2), lst2, comp)
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: merge_iterator(sprout::next(current1), lst1, current2, lst2, comp)
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: merge_iterator(sprout::next(current1), lst1, current2, lst2, comp)
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: current2 != lst2
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? merge_iterator(current1, lst1, sprout::next(current2), lst2, comp)
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: *this
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;
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}
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SPROUT_CXX14_CONSTEXPR void swap(merge_iterator& other)
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SPROUT_NOEXCEPT_EXPR(
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SPROUT_NOEXCEPT_EXPR(sprout::swap(current1, other.current1))
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&& SPROUT_NOEXCEPT_EXPR(sprout::swap(lst1, other.lst1))
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&& SPROUT_NOEXCEPT_EXPR(sprout::swap(current2, other.current2))
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&& SPROUT_NOEXCEPT_EXPR(sprout::swap(lst2, other.lst2))
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&& SPROUT_NOEXCEPT_EXPR(sprout::swap(comp, other.comp))
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&& SPROUT_NOEXCEPT_EXPR(sprout::swap(in_left, other.in_left))
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)
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{
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sprout::swap(current1, other.current1);
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sprout::swap(lst1, other.lst1);
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sprout::swap(current2, other.current2);
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sprout::swap(lst2, other.lst2);
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sprout::swap(comp, other.comp);
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sprout::swap(in_left, other.in_left);
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}
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};
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template<
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typename LIterator1, typename RIterator1, typename Compare1,
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typename LIterator2, typename RIterator2, typename Compare2
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>
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inline SPROUT_CONSTEXPR bool operator==(
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sprout::merge_iterator<LIterator1, RIterator1, Compare1> const& lhs,
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sprout::merge_iterator<LIterator2, RIterator2, Compare2> const& rhs
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)
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{
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return lhs.base() == rhs.base() && lhs.base2() == rhs.base2();
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}
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template<
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typename LIterator1, typename RIterator1, typename Compare1,
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typename LIterator2, typename RIterator2, typename Compare2
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>
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inline SPROUT_CONSTEXPR bool operator!=(
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sprout::merge_iterator<LIterator1, RIterator1, Compare1> const& lhs,
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sprout::merge_iterator<LIterator2, RIterator2, Compare2> const& rhs
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)
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{
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return !(lhs == rhs);
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}
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//
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// make_merge_iterator
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//
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template<typename LIterator, typename RIterator, typename Compare>
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inline SPROUT_CONSTEXPR sprout::merge_iterator<LIterator, RIterator, Compare>
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make_merge_iterator(LIterator it1, LIterator lst1, RIterator it2, RIterator lst2, Compare comp) {
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return sprout::merge_iterator<LIterator, RIterator, Compare>(it1, lst1, it2, lst2, comp);
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}
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template<typename LIterator, typename RIterator>
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inline SPROUT_CONSTEXPR sprout::merge_iterator<LIterator, RIterator>
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make_merge_iterator(LIterator it1, LIterator lst1, RIterator it2, RIterator lst2) {
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return sprout::merge_iterator<LIterator, RIterator>(it1, lst1, it2, lst2);
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}
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//
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// swap
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//
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template<typename LIterator, typename RIterator, typename Compare>
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inline SPROUT_CXX14_CONSTEXPR void
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swap(
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sprout::merge_iterator<LIterator, RIterator, Compare>& lhs,
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sprout::merge_iterator<LIterator, RIterator, Compare>& rhs
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)
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SPROUT_NOEXCEPT_EXPR(SPROUT_NOEXCEPT_EXPR(lhs.swap(rhs)))
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{
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lhs.swap(rhs);
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}
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//
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// iterator_next
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//
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template<typename LIterator, typename RIterator, typename Compare>
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inline SPROUT_CONSTEXPR sprout::merge_iterator<LIterator, RIterator, Compare>
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iterator_next(sprout::merge_iterator<LIterator, RIterator, Compare> const& it) {
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return it.next();
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}
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} // namespace sprout
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#endif // #ifndef SPROUT_ITERATOR_MERGE_ITERATOR_HPP
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