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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
//
//===----------------------------------------------------------------------===//
// constexpr auto size()
// constexpr auto size() const
// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
#include <cassert>
#include <cstddef>
#include <ranges>
struct ConstSizedView : std::ranges::view_base {
bool* size_called;
int* begin() const;
int* end() const;
constexpr std::size_t size() const {
*size_called = true;
return 3;
}
};
struct SizedView : std::ranges::view_base {
bool* size_called;
int* begin() const;
int* end() const;
constexpr int size() {
*size_called = true;
return 5;
}
};
struct UnsizedView : std::ranges::view_base {
int* begin() const;
int* end() const;
};
template <class T>
concept HasSize = requires(T v) { v.size(); };
static_assert(HasSize<ConstSizedView>);
static_assert(HasSize<const ConstSizedView>);
static_assert(HasSize<SizedView>);
static_assert(!HasSize<const SizedView>);
static_assert(!HasSize<UnsizedView>);
static_assert(!HasSize<const UnsizedView>);
constexpr bool test() {
{
bool size_called = false;
std::ranges::as_rvalue_view view(ConstSizedView{{}, &size_called});
std::same_as<std::size_t> auto size = view.size();
assert(size == 3);
assert(size_called);
}
{
bool size_called = false;
std::ranges::as_rvalue_view view(SizedView{{}, &size_called});
std::same_as<int> auto size = view.size();
assert(size == 5);
assert(size_called);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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