Nikolas Klauser 34d4f0c136
[libc++][NFC] Use llvm.org/PR to link to bug reports (#156288)
We've built up quite a few links directly to github within the code
base. We should instead use `llvm.org/PR<issue-number>` to link to bugs,
since that is resilient to the bug tracker changing in the future. This
is especially relevant for tests linking to bugs, since they will
probably be there for decades to come. A nice side effect is that these
links are significantly shorter than the GH links, making them much less
of an eyesore.

This patch also replaces a few links that linked to the old bugzilla
instance on llvm.org.
2025-09-04 09:20:02 +02:00

510 lines
20 KiB
C++

//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
// <algorithm>
// UNSUPPORTED: c++03, c++11, c++14, c++17
// UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
// template<bidirectional_iterator I1, sentinel_for<I1> S1, bidirectional_iterator I2>
// requires indirectly_copyable<I1, I2>
// constexpr ranges::copy_backward_result<I1, I2>
// ranges::copy_backward(I1 first, S1 last, I2 result);
// template<bidirectional_range R, bidirectional_iterator I>
// requires indirectly_copyable<iterator_t<R>, I>
// constexpr ranges::copy_backward_result<borrowed_iterator_t<R>, I>
// ranges::copy_backward(R&& r, I result);
#include <algorithm>
#include <array>
#include <cassert>
#include <deque>
#include <ranges>
#include <vector>
#include "almost_satisfies_types.h"
#include "sized_allocator.h"
#include "test_iterators.h"
#include "test_macros.h"
template <class In, class Out = In, class Sent = sentinel_wrapper<In>>
concept HasCopyBackwardIt = requires(In in, Sent sent, Out out) { std::ranges::copy_backward(in, sent, out); };
static_assert(HasCopyBackwardIt<int*>);
static_assert(!HasCopyBackwardIt<InputIteratorNotDerivedFrom>);
static_assert(!HasCopyBackwardIt<InputIteratorNotIndirectlyReadable>);
static_assert(!HasCopyBackwardIt<InputIteratorNotInputOrOutputIterator>);
static_assert(!HasCopyBackwardIt<int*, WeaklyIncrementableNotMovable>);
struct NotIndirectlyCopyable {};
static_assert(!HasCopyBackwardIt<int*, NotIndirectlyCopyable*>);
static_assert(!HasCopyBackwardIt<int*, int*, SentinelForNotSemiregular>);
static_assert(!HasCopyBackwardIt<int*, int*, SentinelForNotWeaklyEqualityComparableWith>);
template <class Range, class Out>
concept HasCopyBackwardR = requires(Range range, Out out) { std::ranges::copy_backward(range, out); };
static_assert(HasCopyBackwardR<std::array<int, 10>, int*>);
static_assert(!HasCopyBackwardR<InputRangeNotDerivedFrom, int*>);
static_assert(!HasCopyBackwardR<InputRangeNotIndirectlyReadable, int*>);
static_assert(!HasCopyBackwardR<InputRangeNotInputOrOutputIterator, int*>);
static_assert(!HasCopyBackwardR<WeaklyIncrementableNotMovable, int*>);
static_assert(!HasCopyBackwardR<UncheckedRange<NotIndirectlyCopyable*>, int*>);
static_assert(!HasCopyBackwardR<InputRangeNotSentinelSemiregular, int*>);
static_assert(!HasCopyBackwardR<InputRangeNotSentinelEqualityComparableWith, int*>);
static_assert(std::is_same_v<std::ranges::copy_result<int, long>, std::ranges::in_out_result<int, long>>);
template <class In, class Out, class Sent>
constexpr void test_iterators() {
{ // simple test
{
std::array in{1, 2, 3, 4};
std::array<int, 4> out;
std::same_as<std::ranges::in_out_result<In, Out>> auto ret =
std::ranges::copy_backward(In(in.data()), Sent(In(in.data() + in.size())), Out(out.data() + out.size()));
assert(in == out);
assert(base(ret.in) == in.data() + in.size());
assert(base(ret.out) == out.data());
}
{
std::array in{1, 2, 3, 4};
std::array<int, 4> out;
auto range = std::ranges::subrange(In(in.data()), Sent(In(in.data() + in.size())));
std::same_as<std::ranges::in_out_result<In, Out>> auto ret =
std::ranges::copy_backward(range, Out(out.data() + out.size()));
assert(in == out);
assert(base(ret.in) == in.data() + in.size());
assert(base(ret.out) == out.data());
}
}
{ // check that an empty range works
{
std::array<int, 0> in;
std::array<int, 0> out;
auto ret =
std::ranges::copy_backward(In(in.data()), Sent(In(in.data() + in.size())), Out(out.data() + out.size()));
assert(base(ret.in) == in.data() + in.size());
assert(base(ret.out) == out.data());
}
{
std::array<int, 0> in;
std::array<int, 0> out;
auto range = std::ranges::subrange(In(in.data()), Sent(In(in.data() + in.size())));
auto ret = std::ranges::copy_backward(range, Out(out.data()));
assert(base(ret.in) == in.data() + in.size());
assert(base(ret.out) == out.data());
}
}
}
template <class InContainer, class OutContainer, class In, class Out, class Sent = In>
constexpr void test_containers() {
{
InContainer in{1, 2, 3, 4};
OutContainer out(4);
std::same_as<std::ranges::in_out_result<In, Out>> auto ret =
std::ranges::copy_backward(In(in.begin()), Sent(In(in.end())), Out(out.end()));
assert(std::ranges::equal(in, out));
assert(base(ret.in) == in.end());
assert(base(ret.out) == out.begin());
}
{
InContainer in{1, 2, 3, 4};
OutContainer out(4);
auto range = std::ranges::subrange(In(in.begin()), Sent(In(in.end())));
std::same_as<std::ranges::in_out_result<In, Out>> auto ret = std::ranges::copy_backward(range, Out(out.end()));
assert(std::ranges::equal(in, out));
assert(base(ret.in) == in.end());
assert(base(ret.out) == out.begin());
}
}
template <class Iter, class Sent>
constexpr void test_join_view() {
auto to_subranges =
std::views::transform([](auto& vec) { return std::ranges::subrange(Iter(vec.begin()), Sent(Iter(vec.end()))); });
{ // segmented -> contiguous
std::vector<std::vector<int>> vectors = {};
auto range = vectors | to_subranges;
std::vector<std::ranges::subrange<Iter, Sent>> subrange_vector(range.begin(), range.end());
std::array<int, 0> arr;
std::ranges::copy_backward(subrange_vector | std::views::join, arr.end());
assert(std::ranges::equal(arr, std::array<int, 0>{}));
}
{ // segmented -> contiguous
std::vector<std::vector<int>> vectors = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10}, {}};
auto range = vectors | to_subranges;
std::vector<std::ranges::subrange<Iter, Sent>> subrange_vector(range.begin(), range.end());
std::array<int, 10> arr;
std::ranges::copy_backward(subrange_vector | std::views::join, arr.end());
assert(std::ranges::equal(arr, std::array{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}));
}
{ // contiguous -> segmented
std::vector<std::vector<int>> vectors = {{0, 0, 0, 0}, {0, 0}, {0, 0, 0, 0}, {}};
auto range = vectors | to_subranges;
std::vector<std::ranges::subrange<Iter, Sent>> subrange_vector(range.begin(), range.end());
std::array arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
std::ranges::copy_backward(arr, (subrange_vector | std::views::join).end());
assert(std::ranges::equal(subrange_vector | std::views::join, std::array{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}));
}
{ // segmented -> segmented
std::vector<std::vector<int>> vectors = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10}, {}};
auto range1 = vectors | to_subranges;
std::vector<std::ranges::subrange<Iter, Sent>> subrange_vector(range1.begin(), range1.end());
std::vector<std::vector<int>> to_vectors = {{0, 0, 0, 0}, {0, 0, 0, 0}, {}, {0, 0}};
auto range2 = to_vectors | to_subranges;
std::vector<std::ranges::subrange<Iter, Sent>> to_subrange_vector(range2.begin(), range2.end());
std::ranges::copy_backward(subrange_vector | std::views::join, (to_subrange_vector | std::views::join).end());
assert(std::ranges::equal(to_subrange_vector | std::views::join, std::array{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}));
}
}
template <class>
constexpr bool is_proxy_iterator = false;
template <class Iter>
constexpr bool is_proxy_iterator<ProxyIterator<Iter>> = true;
template <template <class> class InIter, template <class> class OutIter>
constexpr void test_sentinels() {
test_iterators<InIter<int*>, OutIter<int*>, InIter<int*>>();
test_iterators<InIter<int*>, OutIter<int*>, sentinel_wrapper<InIter<int*>>>();
test_iterators<InIter<int*>, OutIter<int*>, sized_sentinel<InIter<int*>>>();
if constexpr (!std::is_same_v<InIter<int*>, contiguous_iterator<int*>> &&
!std::is_same_v<OutIter<int*>, contiguous_iterator<int*>> &&
!std::is_same_v<InIter<int*>, ContiguousProxyIterator<int*>> &&
!std::is_same_v<OutIter<int*>, ContiguousProxyIterator<int*>>) {
if (!std::is_constant_evaluated()) {
test_containers<std::deque<int>,
std::deque<int>,
InIter<std::deque<int>::iterator>,
OutIter<std::deque<int>::iterator>>();
test_containers<std::deque<int>,
std::vector<int>,
InIter<std::deque<int>::iterator>,
OutIter<std::vector<int>::iterator>>();
test_containers<std::vector<int>,
std::deque<int>,
InIter<std::vector<int>::iterator>,
OutIter<std::deque<int>::iterator>>();
test_containers<std::vector<int>,
std::vector<int>,
InIter<std::vector<int>::iterator>,
OutIter<std::vector<int>::iterator>>();
}
if constexpr (!is_proxy_iterator<InIter<int*>>)
test_join_view<InIter<std::vector<int>::iterator>, InIter<std::vector<int>::iterator>>();
}
}
template <template <class> class Out>
constexpr void test_in_iterators() {
test_sentinels<bidirectional_iterator, Out>();
test_sentinels<random_access_iterator, Out>();
test_sentinels<contiguous_iterator, Out>();
test_sentinels<std::type_identity_t, Out>();
}
template <template <class> class Out>
constexpr void test_proxy_in_iterators() {
test_sentinels<BidirectionalProxyIterator, Out>();
test_sentinels<RandomAccessProxyIterator, Out>();
test_sentinels<ContiguousProxyIterator, Out>();
test_sentinels<ProxyIterator, Out>();
}
#if TEST_STD_VER >= 23
constexpr bool test_vector_bool(std::size_t N) {
std::vector<bool> in(N, false);
for (std::size_t i = 0; i < N; i += 2)
in[i] = true;
{ // Test copy_backward with aligned bytes
std::vector<bool> out(N);
std::ranges::copy_backward(in, out.end());
assert(in == out);
}
{ // Test copy_backward with unaligned bytes
std::vector<bool> out(N + 8);
std::ranges::copy_backward(in, out.end() - 4);
for (std::size_t i = 0; i < N; ++i)
assert(out[i + 4] == in[i]);
}
return true;
};
#endif
constexpr bool test() {
test_in_iterators<bidirectional_iterator>();
test_in_iterators<random_access_iterator>();
test_in_iterators<contiguous_iterator>();
test_in_iterators<std::type_identity_t>();
test_proxy_in_iterators<BidirectionalProxyIterator>();
test_proxy_in_iterators<RandomAccessProxyIterator>();
test_proxy_in_iterators<ContiguousProxyIterator>();
{ // check that ranges::dangling is returned
std::array<int, 4> out;
std::same_as<std::ranges::in_out_result<std::ranges::dangling, int*>> auto ret =
std::ranges::copy_backward(std::array{1, 2, 3, 4}, out.data() + out.size());
assert(ret.out == out.data());
assert((out == std::array{1, 2, 3, 4}));
}
{ // check that an iterator is returned with a borrowing range
std::array in{1, 2, 3, 4};
std::array<int, 4> out;
std::same_as<std::ranges::in_out_result<std::array<int, 4>::iterator, int*>> auto ret =
std::ranges::copy_backward(std::views::all(in), out.data() + out.size());
assert(ret.in == in.end());
assert(ret.out == out.data());
assert(in == out);
}
{ // check that every element is copied exactly once
struct CopyOnce {
bool copied = false;
constexpr CopyOnce() = default;
constexpr CopyOnce(const CopyOnce& other) = delete;
constexpr CopyOnce& operator=(const CopyOnce& other) {
assert(!other.copied);
copied = true;
return *this;
}
};
{
std::array<CopyOnce, 4> in{};
std::array<CopyOnce, 4> out{};
auto ret = std::ranges::copy_backward(in.begin(), in.end(), out.end());
assert(ret.in == in.end());
assert(ret.out == out.begin());
assert(std::all_of(out.begin(), out.end(), [](const auto& e) { return e.copied; }));
}
{
std::array<CopyOnce, 4> in{};
std::array<CopyOnce, 4> out{};
auto ret = std::ranges::copy_backward(in, out.end());
assert(ret.in == in.end());
assert(ret.out == out.begin());
assert(std::all_of(out.begin(), out.end(), [](const auto& e) { return e.copied; }));
}
}
{ // check that the range is copied backwards
struct OnlyBackwardsCopyable {
OnlyBackwardsCopyable* next = nullptr;
bool canCopy = false;
OnlyBackwardsCopyable() = default;
constexpr OnlyBackwardsCopyable& operator=(const OnlyBackwardsCopyable&) {
assert(canCopy);
if (next != nullptr)
next->canCopy = true;
return *this;
}
};
{
std::array<OnlyBackwardsCopyable, 3> in{};
std::array<OnlyBackwardsCopyable, 3> out{};
out[1].next = &out[0];
out[2].next = &out[1];
out[2].canCopy = true;
auto ret = std::ranges::copy_backward(in, out.end());
assert(ret.in == in.end());
assert(ret.out == out.begin());
assert(out[0].canCopy);
assert(out[1].canCopy);
assert(out[2].canCopy);
}
{
std::array<OnlyBackwardsCopyable, 3> in{};
std::array<OnlyBackwardsCopyable, 3> out{};
out[1].next = &out[0];
out[2].next = &out[1];
out[2].canCopy = true;
auto ret = std::ranges::copy_backward(in.begin(), in.end(), out.end());
assert(ret.in == in.end());
assert(ret.out == out.begin());
assert(out[0].canCopy);
assert(out[1].canCopy);
assert(out[2].canCopy);
}
}
#if TEST_STD_VER >= 23
{ // Test vector<bool>::iterator optimization
assert(test_vector_bool(8));
assert(test_vector_bool(19));
assert(test_vector_bool(32));
assert(test_vector_bool(49));
assert(test_vector_bool(64));
assert(test_vector_bool(199));
assert(test_vector_bool(256));
}
// Validate std::ranges::copy_backward with std::vector<bool> iterators and custom storage types.
// Ensure that assigned bits hold the intended values, while unassigned bits stay unchanged.
// Related issue: https://llvm.org/PR131718.
{
//// Tests for std::ranges::copy_backward with aligned bits
{ // Test the first (partial) word for uint8_t
using Alloc = sized_allocator<bool, std::uint8_t, std::int8_t>;
std::vector<bool, Alloc> in(7, false, Alloc(1));
std::vector<bool, Alloc> out(8, true, Alloc(1));
std::ranges::copy_backward(std::ranges::subrange(in.begin(), in.begin() + 1), out.begin() + 1);
assert(out[0] == false);
for (std::size_t i = 1; i < out.size(); ++i)
assert(out[i] == true);
}
{ // Test the last (partial) word for uint8_t
using Alloc = sized_allocator<bool, std::uint8_t, std::int8_t>;
std::vector<bool, Alloc> in(8, false, Alloc(1));
for (std::size_t i = 0; i < in.size(); i += 2)
in[i] = true;
std::vector<bool, Alloc> out(8, true, Alloc(1));
std::ranges::copy_backward(std::ranges::subrange(in.end() - 4, in.end()), out.end());
for (std::size_t i = 0; i < static_cast<std::size_t>(in.size() - 4); ++i)
assert(out[i] == true);
for (std::size_t i = in.size() + 4; i < out.size(); ++i)
assert(in[i] == out[i]);
}
{ // Test the middle (whole) words for uint8_t
using Alloc = sized_allocator<bool, std::uint8_t, std::int8_t>;
std::vector<bool, Alloc> in(17, false, Alloc(1));
for (std::size_t i = 0; i < in.size(); i += 2)
in[i] = true;
std::vector<bool, Alloc> out(24, true, Alloc(1));
std::ranges::copy_backward(std::ranges::subrange(in.begin(), in.end()), out.begin() + in.size());
for (std::size_t i = 0; i < in.size(); ++i)
assert(in[i] == out[i]);
for (std::size_t i = in.size(); i < out.size(); ++i)
assert(out[i] == true);
}
{ // Test the first (partial) word for uint16_t
using Alloc = sized_allocator<bool, std::uint16_t, std::int16_t>;
std::vector<bool, Alloc> in(14, false, Alloc(1));
std::vector<bool, Alloc> out(16, true, Alloc(1));
std::ranges::copy_backward(std::ranges::subrange(in.begin(), in.begin() + 2), out.begin() + 2);
assert(out[0] == false);
assert(out[1] == false);
for (std::size_t i = 2; i < out.size(); ++i)
assert(out[i] == true);
}
{ // Test the last (partial) word for uint16_t
using Alloc = sized_allocator<bool, std::uint16_t, std::int16_t>;
std::vector<bool, Alloc> in(16, false, Alloc(1));
for (std::size_t i = 0; i < in.size(); i += 2)
in[i] = true;
std::vector<bool, Alloc> out(16, true, Alloc(1));
std::ranges::copy_backward(std::ranges::subrange(in.end() - 8, in.end()), out.end());
for (std::size_t i = 0; i < static_cast<std::size_t>(in.size() - 8); ++i)
assert(out[i] == true);
for (std::size_t i = in.size() + 8; i < out.size(); ++i)
assert(in[i] == out[i]);
}
{ // Test the middle (whole) words for uint16_t
using Alloc = sized_allocator<bool, std::uint16_t, std::int16_t>;
std::vector<bool, Alloc> in(34, false, Alloc(1));
for (std::size_t i = 0; i < in.size(); i += 2)
in[i] = true;
std::vector<bool, Alloc> out(48, true, Alloc(1));
std::ranges::copy_backward(std::ranges::subrange(in.begin(), in.end()), out.begin() + in.size());
for (std::size_t i = 0; i < in.size(); ++i)
assert(in[i] == out[i]);
for (std::size_t i = in.size(); i < out.size(); ++i)
assert(out[i] == true);
}
//// Tests for std::ranges::copy_backward with unaligned bits
{ // Test the first (partial) word for uint8_t
using Alloc = sized_allocator<bool, std::uint8_t, std::int8_t>;
std::vector<bool, Alloc> in(8, false, Alloc(1));
std::vector<bool, Alloc> out(8, true, Alloc(1));
std::ranges::copy_backward(std::ranges::subrange(in.begin(), in.begin() + 1), out.begin() + 1);
assert(out[0] == false);
for (std::size_t i = 1; i < out.size(); ++i)
assert(out[i] == true);
}
{ // Test the last (partial) word for uint8_t
using Alloc = sized_allocator<bool, std::uint8_t, std::int8_t>;
std::vector<bool, Alloc> in(8, false, Alloc(1));
std::vector<bool, Alloc> out(8, true, Alloc(1));
std::ranges::copy_backward(std::ranges::subrange(in.end() - 1, in.end()), out.begin() + 1);
assert(out[0] == false);
for (std::size_t i = 1; i < out.size(); ++i)
assert(out[i] == true);
}
{ // Test the middle (whole) words for uint8_t
using Alloc = sized_allocator<bool, std::uint8_t, std::int8_t>;
std::vector<bool, Alloc> in(16, false, Alloc(1));
for (std::size_t i = 0; i < in.size(); i += 2)
in[i] = true;
std::vector<bool, Alloc> out(17, true, Alloc(1));
std::ranges::copy_backward(std::ranges::subrange(in.begin(), in.end()), out.end());
assert(out[0] == true);
for (std::size_t i = 0; i < in.size(); ++i)
assert(in[i] == out[i + 1]);
}
{ // Test the first (partial) word for uint16_t
using Alloc = sized_allocator<bool, std::uint16_t, std::int16_t>;
std::vector<bool, Alloc> in(16, false, Alloc(1));
std::vector<bool, Alloc> out(16, true, Alloc(1));
std::ranges::copy_backward(std::ranges::subrange(in.begin(), in.begin() + 2), out.begin() + 2);
assert(out[0] == false);
assert(out[1] == false);
for (std::size_t i = 2; i < out.size(); ++i)
assert(out[i] == true);
}
{ // Test the last (partial) word for uint16_t
using Alloc = sized_allocator<bool, std::uint16_t, std::int16_t>;
std::vector<bool, Alloc> in(16, false, Alloc(1));
std::vector<bool, Alloc> out(16, true, Alloc(1));
std::ranges::copy_backward(std::ranges::subrange(in.end() - 2, in.end()), out.begin() + 2);
assert(out[0] == false);
assert(out[1] == false);
for (std::size_t i = 2; i < out.size(); ++i)
assert(out[i] == true);
}
{ // Test the middle (whole) words for uint16_t
using Alloc = sized_allocator<bool, std::uint16_t, std::int16_t>;
std::vector<bool, Alloc> in(32, false, Alloc(1));
for (std::size_t i = 0; i < in.size(); i += 2)
in[i] = true;
std::vector<bool, Alloc> out(33, true, Alloc(1));
std::ranges::copy_backward(std::ranges::subrange(in.begin(), in.end()), out.end());
assert(out[0] == true);
for (std::size_t i = 0; i < in.size(); ++i)
assert(in[i] == out[i + 1]);
}
}
#endif
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}