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// Copyright (C) 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 <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()
{
int x[] = {1,2,3,4,5,6};
auto is_odd = [] (int i) { return i%2==1; };
auto v = x | views::filter(is_odd);
using R = decltype(v);
static_assert(std::same_as<int&, decltype(*v.begin())>);
static_assert(ranges::view<R>);
static_assert(ranges::input_range<R>);
static_assert(ranges::common_range<R>);
static_assert(!ranges::sized_range<R>);
static_assert(ranges::bidirectional_range<R>);
static_assert(!ranges::random_access_range<R>);
static_assert(ranges::range<views::all_t<R>>);
VERIFY( ranges::equal(v, (int[]){1,3,5}) );
VERIFY( ranges::equal(v | views::reverse, (int[]){5,3,1}) );
VERIFY( v.pred()(3) == true );
VERIFY( v.pred()(4) == false );
}
void
test02()
{
int x[] = {1,2,3,4,5,6};
auto f = [flag=false] (int) mutable { return flag = !flag; };
auto v = views::filter(f)(x);
using R = decltype(v);
static_assert(std::same_as<int&, decltype(*v.begin())>);
static_assert(ranges::range<R>);
static_assert(std::copyable<R>);
static_assert(!ranges::view<const R>);
VERIFY( ranges::equal(v, (int[]){1,3,5}) );
}
struct X
{
int i, j;
};
void
test03()
{
X x[] = {{1,3}, {2,5}, {3,7}, {4,9}};
test_range<X, bidirectional_iterator_wrapper> rx(x);
auto v = rx | views::filter([] (auto&& p) { return p.i%2==0; });
int sum = 0;
for (auto i = v.begin(); i != v.end(); ++i)
sum += i->j;
VERIFY( sum == 14 );
}
void
test04()
{
auto yes = [] (int) { return true; };
VERIFY( ranges::equal(views::iota(0) | views::filter(yes) | views::take(1),
(int[]){0}) );
}
// The following tests that filter_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
test05()
{
auto v = test_view<wrapper>{} | views::filter([] (int i) { return i%2 == 0; });
VERIFY( ranges::equal(v, (int[]){2,4}) );
VERIFY( ranges::equal(v, (int[]){2,4}) );
}
int
main()
{
test01();
test02();
test03();
test04();
test05<forward_iterator_wrapper>();
test05<random_access_iterator_wrapper>();
}
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