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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
// constexpr auto begin();
#include <array>
#include <cassert>
#include <ranges>
#include <type_traits>
#include <utility>
#include "test_iterators.h"
struct View : std::ranges::view_base {
int* begin() const;
int* end() const;
};
// Test that begin is not const
template <class T>
concept HasBegin = requires(T t) { t.begin(); };
static_assert(HasBegin<std::ranges::split_view<View, View>>);
static_assert(!HasBegin<const std::ranges::split_view<View, View>>);
template <template <class> class MakeIter>
constexpr void testOne() {
constexpr auto make_subrange = []<class T, std::size_t N>(T(&buffer)[N]) {
using Iter = MakeIter<T*>;
using Sent = sentinel_wrapper<Iter>;
return std::ranges::subrange<Iter, Sent>{Iter{buffer}, Sent{Iter{buffer + N}}};
};
using Iter = MakeIter<int*>;
using Sent = sentinel_wrapper<Iter>;
using Range = std::ranges::subrange<Iter, Sent>;
// empty view
{
std::array<int, 0> a;
Range range{Iter{a.data()}, Sent{Iter{a.data() + a.size()}}};
std::ranges::split_view sv{std::move(range), 1};
auto it = sv.begin();
auto firstRange = *it;
assert(firstRange.begin() == range.begin());
assert(firstRange.end() == range.end());
}
// empty pattern
{
int buffer[] = {1, 2, 3};
auto range = make_subrange(buffer);
std::ranges::split_view sv{std::move(range), std::views::empty<int>};
auto it = sv.begin();
auto firstRange = *it;
assert(firstRange.begin() == range.begin());
assert(firstRange.end() == std::next(range.begin()));
}
// empty view and empty pattern
{
std::array<int, 0> a;
Range range{Iter{a.data()}, Sent{Iter{a.data() + a.size()}}};
std::ranges::split_view sv{std::move(range), std::views::empty<int>};
auto it = sv.begin();
auto firstRange = *it;
assert(firstRange.begin() == range.begin());
assert(firstRange.end() == range.end());
}
// pattern found at the beginning
{
int buffer[] = {1, 2, 3};
auto range = make_subrange(buffer);
int pattern[] = {1, 2};
std::ranges::split_view sv{range, pattern};
auto it = sv.begin();
auto firstRange = *it;
assert(firstRange.begin() == range.begin());
assert(firstRange.end() == range.begin());
}
// pattern found in the middle
{
int buffer[] = {1, 2, 3, 4};
auto range = make_subrange(buffer);
int pattern[] = {2, 3};
std::ranges::split_view sv{range, pattern};
auto it = sv.begin();
auto firstRange = *it;
assert(firstRange.begin() == range.begin());
assert(firstRange.end() == std::next(range.begin()));
}
// pattern found at the end
{
int buffer[] = {1, 2, 3};
auto range = make_subrange(buffer);
int pattern[] = {2, 3};
std::ranges::split_view sv{range, pattern};
auto it = sv.begin();
auto firstRange = *it;
assert(firstRange.begin() == range.begin());
assert(firstRange.end() == std::next(range.begin()));
}
// pattern not found
{
int buffer[] = {1, 2, 3};
auto range = make_subrange(buffer);
int pattern[] = {1, 3};
std::ranges::split_view sv{range, pattern};
auto it = sv.begin();
auto firstRange = *it;
assert(firstRange.begin() == range.begin());
assert(firstRange.end() == range.end());
}
// Make sure that we cache the result of begin() on subsequent calls
{
struct Foo {
int& equalsCalledTimes;
constexpr bool operator==(const Foo&) const {
++equalsCalledTimes;
return true;
}
};
int equalsCalledTimes = 0;
Foo buffer[] = {Foo{equalsCalledTimes}, Foo{equalsCalledTimes}};
auto range = make_subrange(buffer);
std::ranges::split_view sv{range, Foo{equalsCalledTimes}};
assert(equalsCalledTimes == 0);
[[maybe_unused]] auto it1 = sv.begin();
auto calledTimesAfterFirstBegin = equalsCalledTimes;
assert(calledTimesAfterFirstBegin != 0);
for (int i = 0; i < 10; ++i) {
[[maybe_unused]] auto it2 = sv.begin();
assert(equalsCalledTimes == calledTimesAfterFirstBegin);
}
}
}
constexpr bool test() {
testOne<forward_iterator>();
testOne<bidirectional_iterator>();
testOne<random_access_iterator>();
testOne<contiguous_iterator>();
testOne<std::type_identity_t>();
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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