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// 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
// <http://www.gnu.org/licenses/>.
// { dg-options "-std=gnu++2a" }
// { dg-do run { target c++2a } }
#include <algorithm>
#include <ranges>
#include <testsuite_hooks.h>
#include <testsuite_iterators.h>
using __gnu_test::test_range;
using __gnu_test::bidirectional_iterator_wrapper;
using __gnu_test::forward_iterator_wrapper;
using __gnu_test::random_access_iterator_wrapper;
namespace ranges = std::ranges;
namespace views = std::ranges::views;
void
test01()
{
auto p = [] (int i) { return i != 16; };
auto v = views::iota(10) | views::drop_while(p);
VERIFY( ranges::equal(v | views::take(5), (int[]){16,17,18,19,20}) );
using R = decltype(v);
static_assert(ranges::view<R>);
static_assert(!ranges::common_range<R>);
static_assert(ranges::random_access_range<R>);
}
void
test02()
{
int x[] = {1,2,3,4,5};
test_range<int, bidirectional_iterator_wrapper> rx(x);
auto v = rx | views::drop_while([] (int i) { return i<4; });
VERIFY( ranges::equal(v, (int[]){4,5}) );
using R = decltype(v);
static_assert(ranges::view<R>);
static_assert(!ranges::common_range<R>);
static_assert(ranges::bidirectional_range<R>);
}
// The following tests that drop_while_view::begin caches its result.
template<template<typename> typename wrapper>
struct test_view : ranges::view_base
{
bool begin_already_called = false;
static inline int x[] = {1,2,3,4,5};
test_range<int, wrapper> rx{x};
auto
begin()
{
if (begin_already_called)
x[0] = 10;
begin_already_called = true;
return rx.begin();
}
auto
end()
{ return rx.end(); }
};
template<template<typename> typename wrapper>
void
test03()
{
auto v
= test_view<wrapper>{} | views::drop_while([] (int i) { return i<3; });
VERIFY( ranges::equal(v, (int[]){3,4,5}) );
VERIFY( ranges::equal(v, (int[]){3,4,5}) );
}
template<auto drop_while = views::drop_while>
void
test04()
{
// Verify SFINAE behavior.
extern int x[5];
auto p = [] (int*) { return true; };
static_assert(!requires { drop_while(); });
static_assert(!requires { drop_while(x, p, p); });
static_assert(!requires { drop_while(x, p); });
static_assert(!requires { drop_while(p)(x); });
static_assert(!requires { x | (drop_while(p) | views::all); });
static_assert(!requires { (drop_while(p) | views::all)(x); });
static_assert(!requires { drop_while | views::all; });
static_assert(!requires { views::all | drop_while; });
}
int
main()
{
test01();
test02();
test03<forward_iterator_wrapper>();
test03<random_access_iterator_wrapper>();
test04();
}
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