// Copyright (C) 2020-2023 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
// .
// { dg-options "-std=gnu++2a" }
// { dg-do run { target c++2a } }
#include
#include
#include
#include
using __gnu_test::test_range;
using __gnu_test::bidirectional_iterator_wrapper;
namespace ranges = std::ranges;
namespace views = ranges::views;
void
test01()
{
int x[] = {1,2,3,4,5};
auto v = x | views::reverse;
VERIFY( ranges::equal(v, (int[]){5,4,3,2,1}) );
VERIFY( ranges::equal(v | views::reverse, x) );
static_assert(ranges::view);
static_assert(ranges::sized_range);
static_assert(ranges::common_range);
static_assert(ranges::random_access_range);
}
void
test02()
{
int x[] = {1,2,3,4,5};
test_range rx(x);
auto v = views::reverse(rx);
VERIFY( ranges::equal(v, (int[]){5,4,3,2,1}) );
VERIFY( ranges::equal(v | views::reverse, rx) );
static_assert(ranges::view);
static_assert(!ranges::sized_range);
static_assert(ranges::common_range);
static_assert(!ranges::random_access_range);
static_assert(ranges::bidirectional_range);
}
void
test03()
{
int x[] = {1,7,3,6,5,2,4,8};
auto is_even = [] (int i) { return i%2==0; };
int sum = 0;
for (auto i : x | views::reverse | views::filter(is_even))
sum += i;
VERIFY( sum == 20 );
}
void
test04()
{
int x[] = {1,2,3,4,5};
VERIFY( ranges::equal(x | views::reverse | (views::reverse | views::reverse),
(int[]){5,4,3,2,1}) );
}
// The following tests that reverse_view::begin caches its result.
template
struct test_wrapper : bidirectional_iterator_wrapper
{
static inline int increment_count = 0;
using bidirectional_iterator_wrapper::bidirectional_iterator_wrapper;
test_wrapper() : bidirectional_iterator_wrapper()
{ }
test_wrapper
operator++(int)
{
auto tmp = *this;
++*this;
return tmp;
}
test_wrapper&
operator++()
{
++increment_count;
bidirectional_iterator_wrapper::operator++();
return *this;
}
test_wrapper
operator--(int)
{
auto tmp = *this;
--*this;
return tmp;
}
test_wrapper&
operator--()
{
bidirectional_iterator_wrapper::operator--();
return *this;
}
};
void
test05()
{
int x[] = {1,2,3,4,5};
test_range rx(x);
auto v = rx | views::reverse;
VERIFY( ranges::equal(v, (int[]){5,4,3,2,1}) );
VERIFY( ranges::equal(v, (int[]){5,4,3,2,1}) );
VERIFY( test_wrapper::increment_count == 5 );
}
namespace test_ns
{
struct A {};
template
void make_reverse_iterator(T&&) {}
} // namespace test_ns
void
test06()
{
// Check that views::reverse works and does not use ADL which could lead
// to accidentally finding test_ns::make_reverse_iterator(A*).
test_ns::A as[] = {{}, {}};
auto v = as | std::views::reverse;
using V = decltype(v);
static_assert( std::ranges::view );
static_assert( std::ranges::range );
}
template
void
test07()
{
// Verify SFINAE behavior.
static_assert(!requires { reverse(); });
static_assert(!requires { reverse(0, 0); });
static_assert(!requires { reverse(0); });
static_assert(!requires { 0 | reverse; });
}
void
test08()
{
// PR libstdc++/100639
auto v = views::iota(1701ll, 3000ll) | views::reverse | views::take(5);
for (auto x : v)
;
}
int
main()
{
test01();
test02();
test03();
test04();
test05();
test06();
test07();
test08();
}