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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17
// friend constexpr decltype(auto) iter_move(const inner-iterator& i)
// noexcept(noexcept(ranges::iter_move(i.i_.<current>)));
#include <iterator>
#include <cassert>
#include <type_traits>
#include <utility>
#include "../types.h"
namespace adl {
template <bool IsNoexcept = false>
struct MaybeNoexceptIterator {
using value_type = int;
using difference_type = ptrdiff_t;
value_type* ptr_ = nullptr;
int* iter_move_invocations_ = nullptr;
constexpr MaybeNoexceptIterator() = default;
constexpr explicit MaybeNoexceptIterator(int* p, int& iter_moves) : ptr_(p), iter_move_invocations_(&iter_moves) {}
constexpr value_type& operator*() const { return *ptr_; }
MaybeNoexceptIterator& operator++() { ++ptr_; return *this; }
MaybeNoexceptIterator operator++(int) {
MaybeNoexceptIterator prev = *this;
++ptr_;
return prev;
}
constexpr MaybeNoexceptIterator& operator--() { --ptr_; return *this; }
constexpr MaybeNoexceptIterator operator--(int) {
MaybeNoexceptIterator prev = *this;
--ptr_;
return prev;
}
constexpr friend value_type&& iter_move(MaybeNoexceptIterator iter) noexcept(IsNoexcept) {
if (iter.iter_move_invocations_) {
++(*iter.iter_move_invocations_);
}
return std::move(*iter);
}
friend bool operator==(const MaybeNoexceptIterator& lhs, const MaybeNoexceptIterator& rhs) { return lhs.ptr_ == rhs.ptr_; }
};
template <bool IsNoexcept = false>
struct View : std::ranges::view_base {
static constexpr int N = 3;
int a[N] = {0, 1, 2};
int* iter_moves = nullptr;
constexpr View() = default;
constexpr View(int& iter_move_invocations) : iter_moves(&iter_move_invocations) {
}
constexpr adl::MaybeNoexceptIterator<IsNoexcept> begin() {
return adl::MaybeNoexceptIterator<IsNoexcept>(a, *iter_moves);
}
constexpr adl::MaybeNoexceptIterator<IsNoexcept> end() {
return adl::MaybeNoexceptIterator<IsNoexcept>(a + N, *iter_moves);
}
};
} // namespace adl
constexpr bool test() {
// Can use `iter_move` with `inner-iterator`; `View` is a forward range.
{
SplitViewForward v("abc def", " ");
auto segment = *v.begin();
// Non-const iterator.
{
auto i = segment.begin();
static_assert(std::same_as<decltype(iter_move(i)), const char &&>);
assert(iter_move(i) == 'a');
}
// Const iterator.
{
const auto i = segment.begin();
static_assert(std::same_as<decltype(iter_move(i)), const char &&>);
assert(iter_move(i) == 'a');
}
}
// Can use `iter_move` with `inner-iterator`, `View` is an input range.
{
SplitViewInput v("abc def", ' ');
auto segment = *v.begin();
// Non-const iterator.
{
auto i = segment.begin();
static_assert(std::same_as<decltype(iter_move(i)), char &&>);
assert(iter_move(i) == 'a');
}
// Const iterator.
{
const auto i = segment.begin();
static_assert(std::same_as<decltype(iter_move(i)), char &&>);
assert(iter_move(i) == 'a');
}
}
// Ensure the `iter_move` customization point is being used.
{
int iter_move_invocations = 0;
adl::View<> input(iter_move_invocations);
std::ranges::lazy_split_view<adl::View<>, adl::View<>> v(input, adl::View<>());
auto segment = *v.begin();
auto i = segment.begin();
int x = iter_move(i);
assert(x == 0);
assert(iter_move_invocations == 1);
}
// Check the `noexcept` specification.
{
{
using ThrowingSplitView = std::ranges::lazy_split_view<adl::View<false>, adl::View<false>>;
using ThrowingValueType = std::ranges::iterator_t<ThrowingSplitView>::value_type;
using ThrowingIter = std::ranges::iterator_t<ThrowingValueType>;
ASSERT_NOT_NOEXCEPT(std::ranges::iter_move(std::declval<adl::MaybeNoexceptIterator<false>>()));
ASSERT_NOT_NOEXCEPT(iter_move(std::declval<ThrowingIter>()));
}
{
using NoexceptSplitView = std::ranges::lazy_split_view<adl::View<true>, adl::View<true>>;
using NoexceptValueType = std::ranges::iterator_t<NoexceptSplitView>::value_type;
using NoexceptIter = std::ranges::iterator_t<NoexceptValueType>;
ASSERT_NOEXCEPT(std::ranges::iter_move(std::declval<adl::MaybeNoexceptIterator<true>>()));
ASSERT_NOEXCEPT(iter_move(std::declval<NoexceptIter>()));
}
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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