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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
// std::views::common
#include <ranges>
#include <array>
#include <cassert>
#include <concepts>
#include <utility>
#include "test_iterators.h"
#include "types.h"
template <class View, class T>
concept CanBePiped = requires (View&& view, T&& t) {
{ std::forward<View>(view) | std::forward<T>(t) };
};
constexpr bool test() {
int buf[] = {1, 2, 3};
// views::common(r) is equivalent to views::all(r) if r is a common_range
{
{
CommonView view(buf, buf + 3);
std::same_as<CommonView> auto result = std::views::common(view);
assert(result.begin_ == buf);
assert(result.end_ == buf + 3);
}
{
using NotAView = std::array<int, 3>;
NotAView arr = {1, 2, 3};
std::same_as<std::ranges::ref_view<NotAView>> auto result = std::views::common(arr);
assert(result.begin() == arr.begin());
assert(result.end() == arr.end());
}
}
// Otherwise, views::common(r) is equivalent to ranges::common_view{r}
{
NonCommonView view(buf, buf + 3);
std::same_as<std::ranges::common_view<NonCommonView>> auto result = std::views::common(view);
assert(result.base().begin_ == buf);
assert(result.base().end_ == buf + 3);
}
// Test that std::views::common is a range adaptor
{
using SomeView = NonCommonView;
// Test `v | views::common`
{
SomeView view(buf, buf + 3);
std::same_as<std::ranges::common_view<SomeView>> auto result = view | std::views::common;
assert(result.base().begin_ == buf);
assert(result.base().end_ == buf + 3);
}
// Test `adaptor | views::common`
{
SomeView view(buf, buf + 3);
auto f = [](int i) { return i; };
auto const partial = std::views::transform(f) | std::views::common;
using Result = std::ranges::common_view<std::ranges::transform_view<SomeView, decltype(f)>>;
std::same_as<Result> auto result = partial(view);
assert(result.base().base().begin_ == buf);
assert(result.base().base().end_ == buf + 3);
}
// Test `views::common | adaptor`
{
SomeView view(buf, buf + 3);
auto f = [](int i) { return i; };
auto const partial = std::views::common | std::views::transform(f);
using Result = std::ranges::transform_view<std::ranges::common_view<SomeView>, decltype(f)>;
std::same_as<Result> auto result = partial(view);
assert(result.base().base().begin_ == buf);
assert(result.base().base().end_ == buf + 3);
}
// Check SFINAE friendliness
{
struct NotAView { };
static_assert(!std::is_invocable_v<decltype(std::views::common)>);
static_assert(!std::is_invocable_v<decltype(std::views::common), NotAView>);
static_assert( CanBePiped<SomeView&, decltype(std::views::common)>);
static_assert( CanBePiped<int(&)[10], decltype(std::views::common)>);
static_assert(!CanBePiped<int(&&)[10], decltype(std::views::common)>);
static_assert(!CanBePiped<NotAView, decltype(std::views::common)>);
}
}
{
static_assert(std::same_as<decltype(std::views::common), decltype(std::ranges::views::common)>);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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