c2b3986e39
This is in anticipation of https://isocpp.org/files/papers/D2770R0.html, which is ABI-breaking for `join_view`. Differential Revision: https://reviews.llvm.org/D142520
334 lines
13 KiB
C++
334 lines
13 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// <algorithm>
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// UNSUPPORTED: c++03, c++11, c++14, c++17
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// TODO: make `join_view` non-experimental once D2770 is implemented.
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// UNSUPPORTED: !c++experimental
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// template<bidirectional_iterator I1, sentinel_for<I1> S1, bidirectional_iterator I2>
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// requires indirectly_copyable<I1, I2>
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// constexpr ranges::copy_backward_result<I1, I2>
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// ranges::copy_backward(I1 first, S1 last, I2 result);
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// template<bidirectional_range R, bidirectional_iterator I>
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// requires indirectly_copyable<iterator_t<R>, I>
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// constexpr ranges::copy_backward_result<borrowed_iterator_t<R>, I>
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// ranges::copy_backward(R&& r, I result);
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#include <algorithm>
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#include <array>
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#include <cassert>
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#include <deque>
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#include <ranges>
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#include <vector>
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#include "almost_satisfies_types.h"
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#include "test_iterators.h"
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template <class In, class Out = In, class Sent = sentinel_wrapper<In>>
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concept HasCopyBackwardIt = requires(In in, Sent sent, Out out) { std::ranges::copy_backward(in, sent, out); };
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static_assert(HasCopyBackwardIt<int*>);
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static_assert(!HasCopyBackwardIt<InputIteratorNotDerivedFrom>);
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static_assert(!HasCopyBackwardIt<InputIteratorNotIndirectlyReadable>);
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static_assert(!HasCopyBackwardIt<InputIteratorNotInputOrOutputIterator>);
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static_assert(!HasCopyBackwardIt<int*, WeaklyIncrementableNotMovable>);
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struct NotIndirectlyCopyable {};
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static_assert(!HasCopyBackwardIt<int*, NotIndirectlyCopyable*>);
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static_assert(!HasCopyBackwardIt<int*, int*, SentinelForNotSemiregular>);
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static_assert(!HasCopyBackwardIt<int*, int*, SentinelForNotWeaklyEqualityComparableWith>);
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template <class Range, class Out>
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concept HasCopyBackwardR = requires(Range range, Out out) { std::ranges::copy_backward(range, out); };
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static_assert(HasCopyBackwardR<std::array<int, 10>, int*>);
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static_assert(!HasCopyBackwardR<InputRangeNotDerivedFrom, int*>);
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static_assert(!HasCopyBackwardR<InputRangeNotIndirectlyReadable, int*>);
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static_assert(!HasCopyBackwardR<InputRangeNotInputOrOutputIterator, int*>);
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static_assert(!HasCopyBackwardR<WeaklyIncrementableNotMovable, int*>);
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static_assert(!HasCopyBackwardR<UncheckedRange<NotIndirectlyCopyable*>, int*>);
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static_assert(!HasCopyBackwardR<InputRangeNotSentinelSemiregular, int*>);
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static_assert(!HasCopyBackwardR<InputRangeNotSentinelEqualityComparableWith, int*>);
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static_assert(std::is_same_v<std::ranges::copy_result<int, long>, std::ranges::in_out_result<int, long>>);
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template <class In, class Out, class Sent>
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constexpr void test_iterators() {
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{ // simple test
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{
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std::array in {1, 2, 3, 4};
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std::array<int, 4> out;
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std::same_as<std::ranges::in_out_result<In, Out>> auto ret =
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std::ranges::copy_backward(In(in.data()), Sent(In(in.data() + in.size())), Out(out.data() + out.size()));
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assert(in == out);
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assert(base(ret.in) == in.data() + in.size());
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assert(base(ret.out) == out.data());
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}
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{
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std::array in {1, 2, 3, 4};
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std::array<int, 4> out;
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auto range = std::ranges::subrange(In(in.data()), Sent(In(in.data() + in.size())));
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std::same_as<std::ranges::in_out_result<In, Out>> auto ret =
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std::ranges::copy_backward(range, Out(out.data() + out.size()));
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assert(in == out);
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assert(base(ret.in) == in.data() + in.size());
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assert(base(ret.out) == out.data());
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}
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}
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{ // check that an empty range works
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{
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std::array<int, 0> in;
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std::array<int, 0> out;
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auto ret =
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std::ranges::copy_backward(In(in.data()), Sent(In(in.data() + in.size())), Out(out.data() + out.size()));
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assert(base(ret.in) == in.data() + in.size());
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assert(base(ret.out) == out.data());
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}
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{
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std::array<int, 0> in;
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std::array<int, 0> out;
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auto range = std::ranges::subrange(In(in.data()), Sent(In(in.data() + in.size())));
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auto ret = std::ranges::copy_backward(range, Out(out.data()));
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assert(base(ret.in) == in.data() + in.size());
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assert(base(ret.out) == out.data());
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}
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}
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}
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template <class InContainer, class OutContainer, class In, class Out, class Sent = In>
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constexpr void test_containers() {
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{
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InContainer in {1, 2, 3, 4};
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OutContainer out(4);
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std::same_as<std::ranges::in_out_result<In, Out>> auto ret =
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std::ranges::copy_backward(In(in.begin()), Sent(In(in.end())), Out(out.end()));
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assert(std::ranges::equal(in, out));
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assert(base(ret.in) == in.end());
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assert(base(ret.out) == out.begin());
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}
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{
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InContainer in {1, 2, 3, 4};
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OutContainer out(4);
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auto range = std::ranges::subrange(In(in.begin()), Sent(In(in.end())));
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std::same_as<std::ranges::in_out_result<In, Out>> auto ret = std::ranges::copy_backward(range, Out(out.end()));
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assert(std::ranges::equal(in, out));
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assert(base(ret.in) == in.end());
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assert(base(ret.out) == out.begin());
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}
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}
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template <class Iter, class Sent>
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constexpr void test_join_view() {
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auto to_subranges = std::views::transform([](auto& vec) {
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return std::ranges::subrange(Iter(vec.begin()), Sent(Iter(vec.end())));
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});
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{ // segmented -> contiguous
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std::vector<std::vector<int>> vectors = {};
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auto range = vectors | to_subranges;
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std::vector<std::ranges::subrange<Iter, Sent>> subrange_vector(range.begin(), range.end());
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std::array<int, 0> arr;
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std::ranges::copy_backward(subrange_vector | std::views::join, arr.end());
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assert(std::ranges::equal(arr, std::array<int, 0>{}));
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}
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{ // segmented -> contiguous
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std::vector<std::vector<int>> vectors = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10}, {}};
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auto range = vectors | to_subranges;
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std::vector<std::ranges::subrange<Iter, Sent>> subrange_vector(range.begin(), range.end());
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std::array<int, 10> arr;
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std::ranges::copy_backward(subrange_vector | std::views::join, arr.end());
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assert(std::ranges::equal(arr, std::array{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}));
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}
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{ // contiguous -> segmented
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std::vector<std::vector<int>> vectors = {{0, 0, 0, 0}, {0, 0}, {0, 0, 0, 0}, {}};
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auto range = vectors | to_subranges;
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std::vector<std::ranges::subrange<Iter, Sent>> subrange_vector(range.begin(), range.end());
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std::array arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
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std::ranges::copy_backward(arr, (subrange_vector | std::views::join).end());
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assert(std::ranges::equal(subrange_vector | std::views::join, std::array{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}));
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}
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{ // segmented -> segmented
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std::vector<std::vector<int>> vectors = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10}, {}};
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auto range1 = vectors | to_subranges;
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std::vector<std::ranges::subrange<Iter, Sent>> subrange_vector(range1.begin(), range1.end());
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std::vector<std::vector<int>> to_vectors = {{0, 0, 0, 0}, {0, 0, 0, 0}, {}, {0, 0}};
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auto range2 = to_vectors | to_subranges;
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std::vector<std::ranges::subrange<Iter, Sent>> to_subrange_vector(range2.begin(), range2.end());
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std::ranges::copy_backward(subrange_vector | std::views::join, (to_subrange_vector | std::views::join).end());
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assert(std::ranges::equal(to_subrange_vector | std::views::join, std::array{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}));
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}
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}
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template <class>
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constexpr bool is_proxy_iterator = false;
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template <class Iter>
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constexpr bool is_proxy_iterator<ProxyIterator<Iter>> = true;
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template <template <class> class InIter, template <class> class OutIter>
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constexpr void test_sentinels() {
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test_iterators<InIter<int*>, OutIter<int*>, InIter<int*>>();
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test_iterators<InIter<int*>, OutIter<int*>, sentinel_wrapper<InIter<int*>>>();
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test_iterators<InIter<int*>, OutIter<int*>, sized_sentinel<InIter<int*>>>();
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if constexpr (!std::is_same_v<InIter<int*>, contiguous_iterator<int*>> &&
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!std::is_same_v<OutIter<int*>, contiguous_iterator<int*>> &&
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!std::is_same_v<InIter<int*>, ContiguousProxyIterator<int*>> &&
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!std::is_same_v<OutIter<int*>, ContiguousProxyIterator<int*>>) {
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if (!std::is_constant_evaluated()) {
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test_containers<std::deque<int>,
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std::deque<int>,
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InIter<std::deque<int>::iterator>,
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OutIter<std::deque<int>::iterator>>();
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test_containers<std::deque<int>,
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std::vector<int>,
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InIter<std::deque<int>::iterator>,
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OutIter<std::vector<int>::iterator>>();
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test_containers<std::vector<int>,
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std::deque<int>,
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InIter<std::vector<int>::iterator>,
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OutIter<std::deque<int>::iterator>>();
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test_containers<std::vector<int>,
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std::vector<int>,
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InIter<std::vector<int>::iterator>,
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OutIter<std::vector<int>::iterator>>();
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}
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if constexpr (!is_proxy_iterator<InIter<int*>>)
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test_join_view<InIter<std::vector<int>::iterator>, InIter<std::vector<int>::iterator>>();
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}
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}
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template <template <class> class Out>
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constexpr void test_in_iterators() {
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test_sentinels<bidirectional_iterator, Out>();
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test_sentinels<random_access_iterator, Out>();
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test_sentinels<contiguous_iterator, Out>();
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test_sentinels<std::type_identity_t, Out>();
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}
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template <template <class> class Out>
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constexpr void test_proxy_in_iterators() {
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test_sentinels<BidirectionalProxyIterator, Out>();
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test_sentinels<RandomAccessProxyIterator, Out>();
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test_sentinels<ContiguousProxyIterator, Out>();
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test_sentinels<ProxyIterator, Out>();
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}
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constexpr bool test() {
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test_in_iterators<bidirectional_iterator>();
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test_in_iterators<random_access_iterator>();
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test_in_iterators<contiguous_iterator>();
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test_in_iterators<std::type_identity_t>();
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test_proxy_in_iterators<BidirectionalProxyIterator>();
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test_proxy_in_iterators<RandomAccessProxyIterator>();
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test_proxy_in_iterators<ContiguousProxyIterator>();
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{ // check that ranges::dangling is returned
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std::array<int, 4> out;
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std::same_as<std::ranges::in_out_result<std::ranges::dangling, int*>> auto ret =
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std::ranges::copy_backward(std::array {1, 2, 3, 4}, out.data() + out.size());
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assert(ret.out == out.data());
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assert((out == std::array{1, 2, 3, 4}));
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}
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{ // check that an iterator is returned with a borrowing range
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std::array in {1, 2, 3, 4};
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std::array<int, 4> out;
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std::same_as<std::ranges::in_out_result<int*, int*>> auto ret =
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std::ranges::copy_backward(std::views::all(in), out.data() + out.size());
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assert(ret.in == in.data() + in.size());
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assert(ret.out == out.data());
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assert(in == out);
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}
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{ // check that every element is copied exactly once
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struct CopyOnce {
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bool copied = false;
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constexpr CopyOnce() = default;
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constexpr CopyOnce(const CopyOnce& other) = delete;
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constexpr CopyOnce& operator=(const CopyOnce& other) {
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assert(!other.copied);
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copied = true;
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return *this;
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}
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};
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{
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std::array<CopyOnce, 4> in {};
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std::array<CopyOnce, 4> out {};
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auto ret = std::ranges::copy_backward(in.begin(), in.end(), out.end());
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assert(ret.in == in.end());
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assert(ret.out == out.begin());
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assert(std::all_of(out.begin(), out.end(), [](const auto& e) { return e.copied; }));
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}
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{
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std::array<CopyOnce, 4> in {};
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std::array<CopyOnce, 4> out {};
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auto ret = std::ranges::copy_backward(in, out.end());
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assert(ret.in == in.end());
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assert(ret.out == out.begin());
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assert(std::all_of(out.begin(), out.end(), [](const auto& e) { return e.copied; }));
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}
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}
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{ // check that the range is copied backwards
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struct OnlyBackwardsCopyable {
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OnlyBackwardsCopyable* next = nullptr;
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bool canCopy = false;
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OnlyBackwardsCopyable() = default;
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constexpr OnlyBackwardsCopyable& operator=(const OnlyBackwardsCopyable&) {
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assert(canCopy);
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if (next != nullptr)
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next->canCopy = true;
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return *this;
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}
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};
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{
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std::array<OnlyBackwardsCopyable, 3> in {};
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std::array<OnlyBackwardsCopyable, 3> out {};
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out[1].next = &out[0];
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out[2].next = &out[1];
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out[2].canCopy = true;
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auto ret = std::ranges::copy_backward(in, out.end());
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assert(ret.in == in.end());
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assert(ret.out == out.begin());
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assert(out[0].canCopy);
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assert(out[1].canCopy);
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assert(out[2].canCopy);
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}
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{
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std::array<OnlyBackwardsCopyable, 3> in {};
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std::array<OnlyBackwardsCopyable, 3> out {};
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out[1].next = &out[0];
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out[2].next = &out[1];
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out[2].canCopy = true;
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auto ret = std::ranges::copy_backward(in.begin(), in.end(), out.end());
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assert(ret.in == in.end());
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assert(ret.out == out.begin());
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assert(out[0].canCopy);
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assert(out[1].canCopy);
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assert(out[2].canCopy);
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}
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}
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return true;
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}
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int main(int, char**) {
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test();
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static_assert(test());
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return 0;
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}
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