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// Copyright (C) 2019-2020 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// { dg-options "-std=gnu++2a" }
// { dg-do run { target c++2a } }
#include <ranges>
#include <testsuite_hooks.h>
#include <testsuite_iterators.h>
struct R1
{
int i = 0;
int j = 0;
constexpr const int* rbegin() const { return &i; }
friend constexpr const int* rbegin(const R1&& r) { return &r.j; }
};
// N.B. this is a lie, rbegin on an R1 rvalue will return a dangling pointer.
template<> constexpr bool std::ranges::enable_borrowed_range<R1> = true;
void
test01()
{
constexpr R1 r;
// decay-copy(t.rbegin()) if it is a valid expression
// and its type I models input_or_output_iterator.
static_assert( std::ranges::rbegin(r) == &r.i );
static_assert( std::ranges::rbegin(std::move(r)) == &r.i );
}
struct R2
{
int a[2] = { };
constexpr const int* begin() const { return a; }
constexpr const int* end() const { return a + 2; }
friend constexpr const long* begin(const R2&&); // not defined
friend constexpr const long* end(const R2&&); // not defined
};
// N.B. this is a lie, begin/end on an R2 rvalue will return a dangling pointer.
template<> constexpr bool std::ranges::enable_borrowed_range<R2> = true;
void
test02()
{
constexpr R2 r;
// Otherwise, decay-copy(rbegin(t)) if it is a valid expression
// and its type I models input_or_output_iterator [...]
static_assert( std::ranges::rbegin(r)
== std::make_reverse_iterator(std::ranges::end(r)) );
static_assert( std::ranges::rbegin(std::move(r))
== std::make_reverse_iterator(std::ranges::end(std::move(r))) );
}
void
test03()
{
struct R3
: __gnu_test::test_range<int, __gnu_test::bidirectional_iterator_wrapper>
{
R3(int (&a)[2]) : test_range(a) { }
using test_range::begin;
// Replace test_range::end() to return same type as begin()
// so ranges::rbegin will wrap it in a reverse_iterator .
auto end() &
{
using __gnu_test::bidirectional_iterator_wrapper;
return bidirectional_iterator_wrapper<int>(bounds.last, &bounds);
}
};
int a[2] = { };
R3 r(a);
// Otherwise, make_reverse_iterator(ranges::end(t)) if both ranges::begin(t)
// and ranges::end(t) are valid expressions of the same type I which models
// bidirectional_iterator.
VERIFY( std::ranges::rbegin(r) == std::make_reverse_iterator(std::ranges::end(r)) );
}
int
main()
{
test01();
test02();
test03();
}
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