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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: !c++experimental
// constexpr auto begin();
// constexpr auto begin() const
// requires input_range<const V> &&
// is_reference_v<range_reference_t<const V>>;
#include <cassert>
#include <ranges>
#include "types.h"
struct NonSimpleParentView : std::ranges::view_base {
ChildView* begin() { return nullptr; }
const ChildView* begin() const;
const ChildView* end() const;
};
struct SimpleParentView : std::ranges::view_base {
const ChildView* begin() const;
const ChildView* end() const;
};
struct ConstNotRange : std::ranges::view_base {
const ChildView* begin();
const ChildView* end();
};
static_assert(std::ranges::range<ConstNotRange>);
static_assert(!std::ranges::range<const ConstNotRange>);
template <class T>
concept HasConstBegin = requires(const T& t) { t.begin(); };
constexpr bool test() {
int buffer[4][4] = {{1111, 2222, 3333, 4444}, {555, 666, 777, 888}, {99, 1010, 1111, 1212}, {13, 14, 15, 16}};
{
ChildView children[4] = {ChildView(buffer[0]), ChildView(buffer[1]), ChildView(buffer[2]), ChildView(buffer[3])};
auto jv = std::ranges::join_view(ParentView{children});
assert(*jv.begin() == 1111);
}
{
CopyableChild children[4] = {CopyableChild(buffer[0], 4), CopyableChild(buffer[1], 0), CopyableChild(buffer[2], 1),
CopyableChild(buffer[3], 0)};
auto jv = std::ranges::join_view(ParentView{children});
assert(*jv.begin() == 1111);
}
// Parent is empty.
{
CopyableChild children[4] = {CopyableChild(buffer[0]), CopyableChild(buffer[1]), CopyableChild(buffer[2]),
CopyableChild(buffer[3])};
std::ranges::join_view jv(ParentView(children, 0));
assert(jv.begin() == jv.end());
}
// Parent size is one.
{
CopyableChild children[1] = {CopyableChild(buffer[0])};
std::ranges::join_view jv(ParentView(children, 1));
assert(*jv.begin() == 1111);
}
// Parent and child size is one.
{
CopyableChild children[1] = {CopyableChild(buffer[0], 1)};
std::ranges::join_view jv(ParentView(children, 1));
assert(*jv.begin() == 1111);
}
// Parent size is one child is empty
{
CopyableChild children[1] = {CopyableChild(buffer[0], 0)};
std::ranges::join_view jv(ParentView(children, 1));
assert(jv.begin() == jv.end());
}
// Has all empty children.
{
CopyableChild children[4] = {CopyableChild(buffer[0], 0), CopyableChild(buffer[1], 0), CopyableChild(buffer[2], 0),
CopyableChild(buffer[3], 0)};
auto jv = std::ranges::join_view(ParentView{children});
assert(jv.begin() == jv.end());
}
// First child is empty, others are not.
{
CopyableChild children[4] = {CopyableChild(buffer[0], 4), CopyableChild(buffer[1], 0), CopyableChild(buffer[2], 0),
CopyableChild(buffer[3], 0)};
auto jv = std::ranges::join_view(ParentView{children});
assert(*jv.begin() == 1111);
}
// Last child is empty, others are not.
{
CopyableChild children[4] = {CopyableChild(buffer[0], 4), CopyableChild(buffer[1], 4), CopyableChild(buffer[2], 4),
CopyableChild(buffer[3], 0)};
auto jv = std::ranges::join_view(ParentView{children});
assert(*jv.begin() == 1111);
}
{
std::ranges::join_view jv(buffer);
assert(*jv.begin() == 1111);
}
{
const std::ranges::join_view jv(buffer);
assert(*jv.begin() == 1111);
static_assert(HasConstBegin<decltype(jv)>);
}
// !input_range<const V>
{
std::ranges::join_view jv{ConstNotRange{}};
static_assert(!HasConstBegin<decltype(jv)>);
}
// !is_reference_v<range_reference_t<const V>>
{
auto innerRValueRange = std::views::iota(0, 5) | std::views::transform([](int) { return ChildView{}; });
static_assert(!std::is_reference_v<std::ranges::range_reference_t<const decltype(innerRValueRange)>>);
std::ranges::join_view jv{innerRValueRange};
static_assert(!HasConstBegin<decltype(jv)>);
}
// !simple-view<V>
{
std::ranges::join_view<NonSimpleParentView> jv;
static_assert(!std::same_as<decltype(jv.begin()), decltype(std::as_const(jv).begin())>);
}
// simple-view<V> && is_reference_v<range_reference_t<V>>;
{
std::ranges::join_view<SimpleParentView> jv;
static_assert(std::same_as<decltype(jv.begin()), decltype(std::as_const(jv).begin())>);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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