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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
// UNSUPPORTED: libcpp-has-no-incomplete-ranges
// constexpr iterator& operator--();
// requires ref-is-glvalue && bidirectional_range<Base> &&
// bidirectional_range<range_reference_t<Base>> &&
// common_range<range_reference_t<Base>>;
// constexpr iterator operator--(int);
// requires ref-is-glvalue && bidirectional_range<Base> &&
// bidirectional_range<range_reference_t<Base>> &&
// common_range<range_reference_t<Base>>;
#include <cassert>
#include <ranges>
#include <type_traits>
#include "../types.h"
template <class T>
concept CanPreDecrement = requires(T& t) { --t; };
template <class T>
concept CanPostDecrement = requires(T& t) { t--; };
constexpr void noDecrementTest(auto&& jv) {
auto iter = jv.begin();
static_assert(!CanPreDecrement<decltype(iter)>);
static_assert(!CanPostDecrement<decltype(iter)>);
}
constexpr bool test() {
int buffer[4][4] = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}};
{
// outer == ranges::end
std::ranges::join_view jv(buffer);
auto iter = std::next(jv.begin(), 16);
for (int i = 16; i != 0; --i) {
assert(*--iter == i);
}
}
{
// outer == ranges::end
std::ranges::join_view jv(buffer);
auto iter = std::next(jv.begin(), 13);
for (int i = 13; i != 0; --i) {
assert(*--iter == i);
}
}
{
// outer != ranges::end
std::ranges::join_view jv(buffer);
auto iter = std::next(jv.begin(), 12);
for (int i = 12; i != 0; --i) {
assert(*--iter == i);
}
}
{
// outer != ranges::end
std::ranges::join_view jv(buffer);
auto iter = std::next(jv.begin());
for (int i = 1; i != 0; --i) {
assert(*--iter == i);
}
}
{
int small[2][1] = {{1}, {2}};
std::ranges::join_view jv(small);
auto iter = std::next(jv.begin(), 2);
for (int i = 2; i != 0; --i) {
assert(*--iter == i);
}
}
{
#if defined(__GNUG__) && !defined(__clang__)
// This seems to be a gcc bug where evaluating the following code
// at compile time results in wrong array index
if (!std::is_constant_evaluated()) {
#endif
// skip empty inner
BidiCommonInner inners[4] = {buffer[0], {nullptr, 0}, {nullptr, 0}, buffer[1]};
std::ranges::join_view jv(inners);
auto iter = jv.end();
for (int i = 8; i != 0; --i) {
assert(*--iter == i);
}
#if defined(__GNUG__) && !defined(__clang__)
}
#endif
}
{
// basic type checking
std::ranges::join_view jv(buffer);
auto iter1 = std::ranges::next(jv.begin(), 4);
using iterator = decltype(iter1);
decltype(auto) iter2 = --iter1;
static_assert(std::same_as<decltype(iter2), iterator&>);
assert(&iter1 == &iter2);
std::same_as<iterator> decltype(auto) iter3 = iter1--;
assert(iter3 == std::next(iter1));
}
{
// !ref-is-glvalue
BidiCommonInner inners[2] = {buffer[0], buffer[1]};
InnerRValue<BidiCommonOuter<BidiCommonInner>> outer{inners};
std::ranges::join_view jv(outer);
noDecrementTest(jv);
}
{
// !bidirectional_range<Base>
BidiCommonInner inners[2] = {buffer[0], buffer[1]};
SimpleForwardCommonOuter<BidiCommonInner> outer{inners};
std::ranges::join_view jv(outer);
noDecrementTest(jv);
}
{
// !bidirectional_range<range_reference_t<Base>>
ForwardCommonInner inners[2] = {buffer[0], buffer[1]};
std::ranges::join_view jv(inners);
noDecrementTest(jv);
}
{
// LWG3313 `join_view::iterator::operator--` is incorrectly constrained
// `join_view::iterator` should not have `operator--` if
// !common_range<range_reference_t<Base>>
BidiNonCommonInner inners[2] = {buffer[0], buffer[1]};
std::ranges::join_view jv(inners);
auto iter = jv.begin();
static_assert(!CanPreDecrement<decltype(iter)>);
static_assert(!CanPostDecrement<decltype(iter)>);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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