[libcxx-commits] [libcxx] [libc++][ranges] implement `ranges::shift_left` (PR #83231)
Xiaoyang Liu via libcxx-commits
libcxx-commits at lists.llvm.org
Sun Mar 3 17:43:03 PST 2024
https://github.com/xiaoyang-sde updated https://github.com/llvm/llvm-project/pull/83231
>From e0800f119e62a03c9e1c2e494f98a758bf6a0312 Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Tue, 27 Feb 2024 23:47:20 -0800
Subject: [PATCH 01/14] [libc++][ranges] implement ranges::shift_left
---
libcxx/include/CMakeLists.txt | 1 +
.../include/__algorithm/ranges_shift_left.h | 68 +++++++++++++++++++
libcxx/include/__algorithm/shift_left.h | 36 ++++++----
libcxx/include/algorithm | 8 +++
libcxx/include/libcxx.imp | 1 +
libcxx/include/module.modulemap.in | 1 +
libcxx/modules/std/algorithm.inc | 2 +-
...es_robust_against_proxy_iterators.pass.cpp | 3 +
.../niebloid.compile.pass.cpp | 3 +
9 files changed, 109 insertions(+), 14 deletions(-)
create mode 100644 libcxx/include/__algorithm/ranges_shift_left.h
diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index cafd8c6e00d968..22929225fff728 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -183,6 +183,7 @@ set(files
__algorithm/ranges_set_intersection.h
__algorithm/ranges_set_symmetric_difference.h
__algorithm/ranges_set_union.h
+ __algorithm/ranges_shift_left.h
__algorithm/ranges_shuffle.h
__algorithm/ranges_sort.h
__algorithm/ranges_sort_heap.h
diff --git a/libcxx/include/__algorithm/ranges_shift_left.h b/libcxx/include/__algorithm/ranges_shift_left.h
new file mode 100644
index 00000000000000..bf82ce32693824
--- /dev/null
+++ b/libcxx/include/__algorithm/ranges_shift_left.h
@@ -0,0 +1,68 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_RANGES_SHIFT_LEFT_H
+#define _LIBCPP___ALGORITHM_RANGES_SHIFT_LEFT_H
+
+#include <__algorithm/shift_left.h>
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/permutable.h>
+#include <__ranges/concepts.h>
+#include <__ranges/subrange.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+# pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#if _LIBCPP_STD_VER >= 23
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+namespace __shift_left {
+
+struct __fn {
+ template <class _Iter, class _Sent>
+ _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter> static __shift_left_impl(
+ _Iter __first, _Sent __last, iter_difference_t<_Iter> __n) {
+ auto __ret = std::__shift_left<_RangeAlgPolicy>(std::move(__first), std::move(__last), std::move(__n));
+ return {std::move(__ret.first), std::move(__ret.second)};
+ }
+
+ template <permutable _Iter, sentinel_for<_Iter> _Sent>
+ _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter>
+ operator()(_Iter __first, _Sent __last, iter_difference_t<_Iter> __n) const {
+ return __shift_left_impl(std::move(__first), std::move(__last), std::move(__n));
+ }
+
+ template < forward_range _Range>
+ _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Range>
+ operator()(_Range&& __range, range_difference_t<_Range> __n) const {
+ return __shift_left_impl(ranges::begin(__range), ranges::end(__range), std::move(__n));
+ }
+};
+
+} // namespace __shift_left
+
+inline namespace __cpo {
+inline constexpr auto shift_left = __shift_left::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER == 23
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_RANGES_SHIFT_LEFT_H
diff --git a/libcxx/include/__algorithm/shift_left.h b/libcxx/include/__algorithm/shift_left.h
index 06cd7c5f87644e..e6b8153ecebec8 100644
--- a/libcxx/include/__algorithm/shift_left.h
+++ b/libcxx/include/__algorithm/shift_left.h
@@ -24,30 +24,40 @@ _LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 20
-template <class _ForwardIterator>
-inline _LIBCPP_HIDE_FROM_ABI constexpr _ForwardIterator
-shift_left(_ForwardIterator __first,
- _ForwardIterator __last,
- typename iterator_traits<_ForwardIterator>::difference_type __n) {
+template <class _AlgPolicy, class _Iter, class _Sent>
+inline _LIBCPP_HIDE_FROM_ABI constexpr pair<_Iter, _Iter>
+__shift_left(_Iter __first, _Sent __last, typename iterator_traits<_Iter>::difference_type __n) {
+ _Iter __end = _IterOps<_AlgPolicy>::next(__first, __last);
+
if (__n == 0) {
- return __last;
+ return {std::move(__first), std::move(__end)};
}
- _ForwardIterator __m = __first;
- if constexpr (__has_random_access_iterator_category<_ForwardIterator>::value) {
- if (__n >= __last - __first) {
- return __first;
+ _Iter __m = __first;
+ if constexpr (__has_random_access_iterator_category<_Iter>::value) {
+ if (__n >= __end - __first) {
+ return {std::move(__first), std::move(__first)};
}
__m += __n;
} else {
for (; __n > 0; --__n) {
- if (__m == __last) {
- return __first;
+ if (__m == __end) {
+ return {std::move(__first), std::move(__first)};
}
++__m;
}
}
- return std::move(__m, __last, __first);
+
+ _Iter __result = std::__move<_AlgPolicy>(__m, __end, __first).second;
+ return {std::move(__first), std::move(__result)};
+}
+
+template <class _ForwardIterator>
+inline _LIBCPP_HIDE_FROM_ABI constexpr _ForwardIterator
+shift_left(_ForwardIterator __first,
+ _ForwardIterator __last,
+ typename iterator_traits<_ForwardIterator>::difference_type __n) {
+ return std::__shift_left<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __n).second;
}
#endif // _LIBCPP_STD_VER >= 20
diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm
index 70e30bc87e8128..d9b4e87a8a2ad8 100644
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -843,6 +843,13 @@ namespace ranges {
uniform_random_bit_generator<remove_reference_t<Gen>>
O sample(R&& r, O out, range_difference_t<R> n, Gen&& g); // since C++20
+ template<permutable I, sentinel_for<I> S>
+ constexpr subrange<I> ranges::shift_left(I first, S last, iter_difference_t<I> n); // since C++23
+
+ template<forward_range R>
+ requires permutable<iterator_t<R>>
+ constexpr borrowed_subrange_t<R> ranges::shift_left(R&& r, range_difference_t<R> n) // since C++23
+
template<random_access_iterator I, sentinel_for<I> S, class Gen>
requires permutable<I> &&
uniform_random_bit_generator<remove_reference_t<Gen>>
@@ -1960,6 +1967,7 @@ template <class BidirectionalIterator, class Compare>
#include <__algorithm/ranges_set_intersection.h>
#include <__algorithm/ranges_set_symmetric_difference.h>
#include <__algorithm/ranges_set_union.h>
+#include <__algorithm/ranges_shift_left.h>
#include <__algorithm/ranges_shuffle.h>
#include <__algorithm/ranges_sort.h>
#include <__algorithm/ranges_sort_heap.h>
diff --git a/libcxx/include/libcxx.imp b/libcxx/include/libcxx.imp
index 22fbea99b848bb..1af11eba2d260d 100644
--- a/libcxx/include/libcxx.imp
+++ b/libcxx/include/libcxx.imp
@@ -183,6 +183,7 @@
{ include: [ "<__algorithm/ranges_set_intersection.h>", "private", "<algorithm>", "public" ] },
{ include: [ "<__algorithm/ranges_set_symmetric_difference.h>", "private", "<algorithm>", "public" ] },
{ include: [ "<__algorithm/ranges_set_union.h>", "private", "<algorithm>", "public" ] },
+ { include: [ "<__algorithm/ranges_shift_left.h>", "private", "<algorithm>", "public" ] },
{ include: [ "<__algorithm/ranges_shuffle.h>", "private", "<algorithm>", "public" ] },
{ include: [ "<__algorithm/ranges_sort.h>", "private", "<algorithm>", "public" ] },
{ include: [ "<__algorithm/ranges_sort_heap.h>", "private", "<algorithm>", "public" ] },
diff --git a/libcxx/include/module.modulemap.in b/libcxx/include/module.modulemap.in
index 219906aa9a5668..def640397570d8 100644
--- a/libcxx/include/module.modulemap.in
+++ b/libcxx/include/module.modulemap.in
@@ -987,6 +987,7 @@ module std_private_algorithm_ranges_set_union [system
export std_private_algorithm_in_in_out_result
export std_private_functional_ranges_operations
}
+module std_private_algorithm_ranges_shift_left [system] { header "__algorithm/ranges_shift_left.h" }
module std_private_algorithm_ranges_shuffle [system] { header "__algorithm/ranges_shuffle.h" }
module std_private_algorithm_ranges_sort [system] {
header "__algorithm/ranges_sort.h"
diff --git a/libcxx/modules/std/algorithm.inc b/libcxx/modules/std/algorithm.inc
index e7796bfa26af81..0a4e1c1ba6cc96 100644
--- a/libcxx/modules/std/algorithm.inc
+++ b/libcxx/modules/std/algorithm.inc
@@ -354,7 +354,7 @@ export namespace std {
using std::shift_left;
namespace ranges {
- // using std::ranges::shift_left;
+ using std::ranges::shift_left;
}
using std::shift_right;
diff --git a/libcxx/test/std/algorithms/ranges_robust_against_proxy_iterators.pass.cpp b/libcxx/test/std/algorithms/ranges_robust_against_proxy_iterators.pass.cpp
index 139f1999bc9dca..c64945e34994d3 100644
--- a/libcxx/test/std/algorithms/ranges_robust_against_proxy_iterators.pass.cpp
+++ b/libcxx/test/std/algorithms/ranges_robust_against_proxy_iterators.pass.cpp
@@ -154,6 +154,9 @@ constexpr void run_tests() {
test(std::ranges::remove_if, in, unary_pred);
test(std::ranges::reverse, in);
test_mid(std::ranges::rotate, in, mid);
+#if TEST_STD_VER >= 23
+ test(std::ranges::shift_left, in, count);
+#endif
if (!std::is_constant_evaluated()) // `shuffle` isn't `constexpr`.
test(std::ranges::shuffle, in, rand_gen());
if (!std::is_constant_evaluated()) {
diff --git a/libcxx/test/std/library/description/conventions/customization.point.object/niebloid.compile.pass.cpp b/libcxx/test/std/library/description/conventions/customization.point.object/niebloid.compile.pass.cpp
index 9506ca1c768bd7..886d112b5276d7 100644
--- a/libcxx/test/std/library/description/conventions/customization.point.object/niebloid.compile.pass.cpp
+++ b/libcxx/test/std/library/description/conventions/customization.point.object/niebloid.compile.pass.cpp
@@ -146,6 +146,9 @@ static_assert(test(std::ranges::set_difference, a, a, a));
static_assert(test(std::ranges::set_intersection, a, a, a));
static_assert(test(std::ranges::set_symmetric_difference, a, a, a));
static_assert(test(std::ranges::set_union, a, a, a));
+#if TEST_STD_VER >= 23
+static_assert(test(std::ranges::shift_left, a, 42));
+#endif
static_assert(test(std::ranges::shuffle, a, g));
static_assert(test(std::ranges::sort, a));
static_assert(test(std::ranges::sort_heap, a));
>From 68a86357dee32a6958fa1e8e89940c7ca354277b Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Wed, 28 Feb 2024 00:30:35 -0800
Subject: [PATCH 02/14] [libc++][ranges] format code with 'clang-format'
---
.../algorithms/ranges_robust_against_proxy_iterators.pass.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libcxx/test/std/algorithms/ranges_robust_against_proxy_iterators.pass.cpp b/libcxx/test/std/algorithms/ranges_robust_against_proxy_iterators.pass.cpp
index c64945e34994d3..92b224e427ab3b 100644
--- a/libcxx/test/std/algorithms/ranges_robust_against_proxy_iterators.pass.cpp
+++ b/libcxx/test/std/algorithms/ranges_robust_against_proxy_iterators.pass.cpp
@@ -155,7 +155,7 @@ constexpr void run_tests() {
test(std::ranges::reverse, in);
test_mid(std::ranges::rotate, in, mid);
#if TEST_STD_VER >= 23
- test(std::ranges::shift_left, in, count);
+ test(std::ranges::shift_left, in, count);
#endif
if (!std::is_constant_evaluated()) // `shuffle` isn't `constexpr`.
test(std::ranges::shuffle, in, rand_gen());
>From ade17074240be5093dd83bc53b277e505152f213 Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Wed, 28 Feb 2024 11:28:07 -0800
Subject: [PATCH 03/14] [libc++][ranges] check '_LIBCPP_STD_VER' in
'algorithm.inc'
---
libcxx/modules/std/algorithm.inc | 2 ++
1 file changed, 2 insertions(+)
diff --git a/libcxx/modules/std/algorithm.inc b/libcxx/modules/std/algorithm.inc
index 0a4e1c1ba6cc96..2364899c1e0315 100644
--- a/libcxx/modules/std/algorithm.inc
+++ b/libcxx/modules/std/algorithm.inc
@@ -353,9 +353,11 @@ export namespace std {
// [alg.shift], shift
using std::shift_left;
+#if _LIBCPP_STD_VER >= 23
namespace ranges {
using std::ranges::shift_left;
}
+#endif // _LIBCPP_STD_VER >= 23
using std::shift_right;
>From c84792977c9ed053915e27097e0c7f9d03d99d2b Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Wed, 28 Feb 2024 11:54:13 -0800
Subject: [PATCH 04/14] [libc++][ranges] add missing headers to 'shift_left.h'
and 'ranges_shift_left.h'
---
libcxx/include/__algorithm/ranges_shift_left.h | 1 +
libcxx/include/__algorithm/shift_left.h | 1 +
2 files changed, 2 insertions(+)
diff --git a/libcxx/include/__algorithm/ranges_shift_left.h b/libcxx/include/__algorithm/ranges_shift_left.h
index bf82ce32693824..4595fc7d7031ec 100644
--- a/libcxx/include/__algorithm/ranges_shift_left.h
+++ b/libcxx/include/__algorithm/ranges_shift_left.h
@@ -16,6 +16,7 @@
#include <__ranges/concepts.h>
#include <__ranges/subrange.h>
#include <__utility/move.h>
+#include <__utility/pair.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
diff --git a/libcxx/include/__algorithm/shift_left.h b/libcxx/include/__algorithm/shift_left.h
index e6b8153ecebec8..01d9f1c035f36d 100644
--- a/libcxx/include/__algorithm/shift_left.h
+++ b/libcxx/include/__algorithm/shift_left.h
@@ -9,6 +9,7 @@
#ifndef _LIBCPP___ALGORITHM_SHIFT_LEFT_H
#define _LIBCPP___ALGORITHM_SHIFT_LEFT_H
+#include <__algorithm/iterator_operations.h>
#include <__algorithm/move.h>
#include <__config>
#include <__iterator/iterator_traits.h>
>From 40691ad54b3dc1d30b1edf93138c7adfaa2ab8cc Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Wed, 28 Feb 2024 12:33:50 -0800
Subject: [PATCH 05/14] [libc++][ranges] add missing headers to 'shift_left.h'
---
libcxx/include/__algorithm/shift_left.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/libcxx/include/__algorithm/shift_left.h b/libcxx/include/__algorithm/shift_left.h
index 01d9f1c035f36d..8df1bff87f0427 100644
--- a/libcxx/include/__algorithm/shift_left.h
+++ b/libcxx/include/__algorithm/shift_left.h
@@ -13,6 +13,7 @@
#include <__algorithm/move.h>
#include <__config>
#include <__iterator/iterator_traits.h>
+#include <__utility/pair.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
>From 4de17871d76a7a390f127962ed6036ea233496d7 Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Wed, 28 Feb 2024 12:34:21 -0800
Subject: [PATCH 06/14] [libc++][ranges] add missing constraints to
'ranges_shift_left.h'
---
libcxx/include/__algorithm/ranges_shift_left.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/libcxx/include/__algorithm/ranges_shift_left.h b/libcxx/include/__algorithm/ranges_shift_left.h
index 4595fc7d7031ec..bee3e865c87ed5 100644
--- a/libcxx/include/__algorithm/ranges_shift_left.h
+++ b/libcxx/include/__algorithm/ranges_shift_left.h
@@ -46,7 +46,8 @@ struct __fn {
return __shift_left_impl(std::move(__first), std::move(__last), std::move(__n));
}
- template < forward_range _Range>
+ template <forward_range _Range>
+ requires permutable<iterator_t<_Range>>
_LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Range>
operator()(_Range&& __range, range_difference_t<_Range> __n) const {
return __shift_left_impl(ranges::begin(__range), ranges::end(__range), std::move(__n));
@@ -62,7 +63,7 @@ inline constexpr auto shift_left = __shift_left::__fn{};
_LIBCPP_END_NAMESPACE_STD
-#endif // _LIBCPP_STD_VER == 23
+#endif // _LIBCPP_STD_VER >= 23
_LIBCPP_POP_MACROS
>From 02a20d966ee090a749d88c22f346210f26d666af Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Wed, 28 Feb 2024 12:38:39 -0800
Subject: [PATCH 07/14] [libc++][ranges] format code with 'clang-format'
---
libcxx/include/__algorithm/ranges_shift_left.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libcxx/include/__algorithm/ranges_shift_left.h b/libcxx/include/__algorithm/ranges_shift_left.h
index bee3e865c87ed5..9a0cd3a4223c05 100644
--- a/libcxx/include/__algorithm/ranges_shift_left.h
+++ b/libcxx/include/__algorithm/ranges_shift_left.h
@@ -47,7 +47,7 @@ struct __fn {
}
template <forward_range _Range>
- requires permutable<iterator_t<_Range>>
+ requires permutable<iterator_t<_Range>>
_LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Range>
operator()(_Range&& __range, range_difference_t<_Range> __n) const {
return __shift_left_impl(ranges::begin(__range), ranges::end(__range), std::move(__n));
>From 9bd0eacf41c05c531e69c8bd920c5f0f54cffdc0 Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Wed, 28 Feb 2024 16:03:17 -0800
Subject: [PATCH 08/14] [libc++][ranges] add missing headers to
'ranges_shift_left.h'
---
libcxx/include/__algorithm/ranges_shift_left.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/libcxx/include/__algorithm/ranges_shift_left.h b/libcxx/include/__algorithm/ranges_shift_left.h
index 9a0cd3a4223c05..d9edf661d1d8ca 100644
--- a/libcxx/include/__algorithm/ranges_shift_left.h
+++ b/libcxx/include/__algorithm/ranges_shift_left.h
@@ -9,10 +9,13 @@
#ifndef _LIBCPP___ALGORITHM_RANGES_SHIFT_LEFT_H
#define _LIBCPP___ALGORITHM_RANGES_SHIFT_LEFT_H
+#include <__algorithm/iterator_operations.h>
#include <__algorithm/shift_left.h>
#include <__config>
#include <__iterator/concepts.h>
+#include <__iterator/incrementable_traits.h>
#include <__iterator/permutable.h>
+#include <__ranges/access.h>
#include <__ranges/concepts.h>
#include <__ranges/subrange.h>
#include <__utility/move.h>
>From 7747973ecca54399cebb000beb039bf044523a6c Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Wed, 28 Feb 2024 18:44:12 -0800
Subject: [PATCH 09/14] [libc++][ranges] implement 'ranges.shift_left.pass.cpp'
to test 'ranges::shift_left.h'
---
.../alg.shift/ranges.shift_left.pass.cpp | 194 ++++++++++++++++++
1 file changed, 194 insertions(+)
create mode 100644 libcxx/test/std/algorithms/alg.modifying.operations/alg.shift/ranges.shift_left.pass.cpp
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.shift/ranges.shift_left.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.shift/ranges.shift_left.pass.cpp
new file mode 100644
index 00000000000000..38ef57d3bca005
--- /dev/null
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.shift/ranges.shift_left.pass.cpp
@@ -0,0 +1,194 @@
+//===----------------------------------------------------------------------===//
+//
+// 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, c++20
+
+// template<permutable I, sentinel_for<I> S>
+// constexpr subrange<I> ranges::shift_left(I first, S last, iter_difference_t<I> n);
+
+// template<forward_range R>
+// requires permutable<iterator_t<R>>
+// constexpr borrowed_subrange_t<R> ranges::shift_left(R&& r, range_difference_t<R> n)
+
+#include <algorithm>
+#include <array>
+#include <ranges>
+#include <iterator>
+
+#include "almost_satisfies_types.h"
+#include "test_iterators.h"
+#include "MoveOnly.h"
+
+template <class Iter, class Sent = Iter, class Count = std::size_t>
+concept HasShiftLeftIt = requires(Iter iter, Sent sent, Count n) { std::ranges::shift_left(iter, sent, n); };
+
+static_assert(HasShiftLeftIt<int*>);
+static_assert(!HasShiftLeftIt<ForwardIteratorNotDerivedFrom>);
+static_assert(!HasShiftLeftIt<PermutableNotForwardIterator>);
+static_assert(!HasShiftLeftIt<PermutableNotSwappable>);
+
+template <class Range, class Count = std::size_t>
+concept HasShiftLeftR = requires(Range range, Count n) { std::ranges::shift_left(range, n); };
+
+static_assert(HasShiftLeftR<UncheckedRange<int*>>);
+static_assert(!HasShiftLeftR<ForwardRangeNotDerivedFrom>);
+static_assert(!HasShiftLeftR<PermutableRangeNotForwardIterator>);
+static_assert(!HasShiftLeftR<PermutableRangeNotSwappable>);
+
+template <class Iter, class Sent>
+constexpr void test_iter_sent() {
+ {
+ const std::array<int, 15> original = {3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8, 9, 7, 9};
+ std::array<int, 15> scratch;
+
+ // (iterator, sentinel) overload
+ for (size_t n = 0; n <= 15; ++n) {
+ for (size_t k = 0; k <= n + 2; ++k) {
+ auto begin = Iter(scratch.data());
+ auto end = Sent(Iter(scratch.data() + n));
+ std::ranges::copy(original.begin(), original.begin() + n, begin);
+ auto result = std::ranges::shift_left(begin, end, k);
+
+ assert(result.begin() == begin);
+ if (k < n) {
+ assert(result.end() == Iter(scratch.data() + n - k));
+ assert(std::ranges::equal(original.begin() + k, original.begin() + n, result.begin(), result.end()));
+ } else {
+ assert(result.end() == begin);
+ assert(std::ranges::equal(original.begin(), original.begin() + n, begin, end));
+ }
+ }
+ }
+
+ // (range) overload
+ for (size_t n = 0; n <= 15; ++n) {
+ for (size_t k = 0; k <= n + 2; ++k) {
+ auto begin = Iter(scratch.data());
+ auto end = Sent(Iter(scratch.data() + n));
+ std::ranges::copy(original.begin(), original.begin() + n, begin);
+ auto range = std::ranges::subrange(begin, end);
+ auto result = std::ranges::shift_left(range, k);
+
+ assert(result.begin() == begin);
+ if (k < n) {
+ assert(result.end() == Iter(scratch.data() + n - k));
+ assert(std::ranges::equal(original.begin() + k, original.begin() + n, begin, result.end()));
+ } else {
+ assert(result.end() == begin);
+ assert(std::ranges::equal(original.begin(), original.begin() + n, begin, end));
+ }
+ }
+ }
+ }
+
+ // n == 0
+ {
+ std::array<int, 3> input = {0, 1, 2};
+ const std::array<int, 3> expected = {0, 1, 2};
+
+ { // (iterator, sentinel) overload
+ auto in = input;
+ auto begin = Iter(in.data());
+ auto end = Sent(Iter(in.data() + in.size()));
+ auto result = std::ranges::shift_left(begin, end, 0);
+ assert(std::ranges::equal(expected, result));
+ assert(result.begin() == begin);
+ assert(result.end() == end);
+ }
+
+ { // (range) overload
+ auto in = input;
+ auto begin = Iter(in.data());
+ auto end = Sent(Iter(in.data() + in.size()));
+ auto range = std::ranges::subrange(begin, end);
+ auto result = std::ranges::shift_left(range, 0);
+ assert(std::ranges::equal(expected, result));
+ assert(result.begin() == begin);
+ assert(result.end() == end);
+ }
+ }
+
+ // n == len
+ {
+ std::array<int, 3> input = {0, 1, 2};
+ const std::array<int, 3> expected = {0, 1, 2};
+
+ { // (iterator, sentinel) overload
+ auto in = input;
+ auto begin = Iter(in.data());
+ auto end = Sent(Iter(in.data() + in.size()));
+ auto result = std::ranges::shift_left(begin, end, input.size());
+ assert(std::ranges::equal(expected, input));
+ assert(result.begin() == begin);
+ assert(result.end() == begin);
+ }
+
+ { // (range) overload
+ auto in = input;
+ auto begin = Iter(in.data());
+ auto end = Sent(Iter(in.data() + in.size()));
+ auto range = std::ranges::subrange(begin, end);
+ auto result = std::ranges::shift_left(range, input.size());
+ assert(std::ranges::equal(expected, input));
+ assert(result.begin() == begin);
+ assert(result.end() == begin);
+ }
+ }
+
+ // n > len
+ {
+ std::array<int, 3> input = {0, 1, 2};
+ const std::array<int, 3> expected = {0, 1, 2};
+
+ { // (iterator, sentinel) overload
+ auto in = input;
+ auto begin = Iter(in.data());
+ auto end = Sent(Iter(in.data() + in.size()));
+ auto result = std::ranges::shift_left(begin, end, input.size() + 1);
+ assert(std::ranges::equal(expected, input));
+ assert(result.begin() == begin);
+ assert(result.end() == begin);
+ }
+
+ { // (range) overload
+ auto in = input;
+ auto begin = Iter(in.data());
+ auto end = Sent(Iter(in.data() + in.size()));
+ auto range = std::ranges::subrange(begin, end);
+ auto result = std::ranges::shift_left(range, input.size() + 1);
+ assert(std::ranges::equal(expected, input));
+ assert(result.begin() == begin);
+ assert(result.end() == begin);
+ }
+ }
+}
+
+template <class Iter>
+constexpr void test_iter() {
+ test_iter_sent<Iter, Iter>();
+ test_iter_sent<Iter, sentinel_wrapper<Iter>>();
+ test_iter_sent<Iter, sized_sentinel<Iter>>();
+}
+
+constexpr bool test() {
+ test_iter<forward_iterator<int*>>();
+ test_iter<bidirectional_iterator<int*>>();
+ test_iter<random_access_iterator<int*>>();
+ test_iter<contiguous_iterator<int*>>();
+ test_iter<int*>();
+ return true;
+}
+
+int main(int, char**) {
+ test();
+ static_assert(test());
+
+ return 0;
+}
>From aa1f598453e5a586e18c46993baa0cc5327effd9 Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Wed, 28 Feb 2024 18:50:42 -0800
Subject: [PATCH 10/14] [libc++][ranges] update the implementation status of
'P2440R1'
---
libcxx/docs/Status/Cxx23Papers.csv | 2 +-
libcxx/docs/Status/RangesAlgorithms.csv | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/libcxx/docs/Status/Cxx23Papers.csv b/libcxx/docs/Status/Cxx23Papers.csv
index eb415ed8c031fa..5232d24f66ab6f 100644
--- a/libcxx/docs/Status/Cxx23Papers.csv
+++ b/libcxx/docs/Status/Cxx23Papers.csv
@@ -46,7 +46,7 @@
"`P2255R2 <https://wg21.link/P2255R2>`__","LWG","A type trait to detect reference binding to temporary","February 2022","",""
"`P2273R3 <https://wg21.link/P2273R3>`__","LWG","Making ``std::unique_ptr`` constexpr","February 2022","|Complete|","16.0"
"`P2387R3 <https://wg21.link/P2387R3>`__","LWG","Pipe support for user-defined range adaptors","February 2022","","","|ranges|"
-"`P2440R1 <https://wg21.link/P2440R1>`__","LWG","``ranges::iota``, ``ranges::shift_left`` and ``ranges::shift_right``","February 2022","","","|ranges|"
+"`P2440R1 <https://wg21.link/P2440R1>`__","LWG","``ranges::iota``, ``ranges::shift_left`` and ``ranges::shift_right``","February 2022","|In progress|","","|ranges|"
"`P2441R2 <https://wg21.link/P2441R2>`__","LWG","``views::join_with``","February 2022","|In Progress|","","|ranges|"
"`P2442R1 <https://wg21.link/P2442R1>`__","LWG","Windowing range adaptors: ``views::chunk`` and ``views::slide``","February 2022","","","|ranges|"
"`P2443R1 <https://wg21.link/P2443R1>`__","LWG","``views::chunk_by``","February 2022","|Complete|","18.0","|ranges|"
diff --git a/libcxx/docs/Status/RangesAlgorithms.csv b/libcxx/docs/Status/RangesAlgorithms.csv
index f7a51f732c4b14..1d9582373ea8a0 100644
--- a/libcxx/docs/Status/RangesAlgorithms.csv
+++ b/libcxx/docs/Status/RangesAlgorithms.csv
@@ -5,7 +5,7 @@ C++23,`find_last_if <https://wg21.link/P1223R5>`_,Unassigned,No patch yet,Not st
C++23,`find_last_if_not <https://wg21.link/P1223R5>`_,Unassigned,No patch yet,Not started
C++23,`starts_with <https://wg21.link/P1659R3>`_,Zijun Zhao,`D150735 <https://llvm.org/D150735>`_,Complete
C++23,`ends_with <https://wg21.link/P1659R3>`_,Zijun Zhao, `D150831 <https://llvm.org/D150831>`_,Complete
-C++23,`shift_left <https://wg21.link/p2440r1>`_,Unassigned,No patch yet,Not started
+C++23,`shift_left <https://wg21.link/p2440r1>`_,Xiaoyang Liu,`83231 <https://github.com/llvm/llvm-project/pull/83231>`,✅
C++23,`shift_right <https://wg21.link/p2440r1>`_,Unassigned,No patch yet,Not started
C++23,`iota (algorithm) <https://wg21.link/p2440r1>`_,Unassigned,No patch yet,Not started
C++23,`fold <https://wg21.link/p2322r5>`_,Unassigned,No patch yet,Not started
>From a68eb0265cfc3851221fd77ab2e71e4cb020c145 Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Wed, 28 Feb 2024 19:37:13 -0800
Subject: [PATCH 11/14] [libc++][ranges] attempt to reduce the steps required
for 'constexpr' evaluation in 'ranges.shift_left.pass.cpp'
---
.../alg.shift/ranges.shift_left.pass.cpp | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.shift/ranges.shift_left.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.shift/ranges.shift_left.pass.cpp
index 38ef57d3bca005..2e664e47a17e2f 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.shift/ranges.shift_left.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.shift/ranges.shift_left.pass.cpp
@@ -45,11 +45,11 @@ static_assert(!HasShiftLeftR<PermutableRangeNotSwappable>);
template <class Iter, class Sent>
constexpr void test_iter_sent() {
{
- const std::array<int, 15> original = {3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8, 9, 7, 9};
- std::array<int, 15> scratch;
+ const std::array<int, 8> original = {3, 1, 4, 1, 5, 9, 2, 6};
+ std::array<int, 8> scratch;
// (iterator, sentinel) overload
- for (size_t n = 0; n <= 15; ++n) {
+ for (size_t n = 0; n <= original.size(); ++n) {
for (size_t k = 0; k <= n + 2; ++k) {
auto begin = Iter(scratch.data());
auto end = Sent(Iter(scratch.data() + n));
>From 020a097ceb2079471d25ffcba7fb17a0ded98e70 Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Wed, 28 Feb 2024 20:58:56 -0800
Subject: [PATCH 12/14] [libc++][ranges] fix an out-of-bounds access in
'ranges.shift_left.pass.cpp'
---
.../alg.shift/ranges.shift_left.pass.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libcxx/test/std/algorithms/alg.modifying.operations/alg.shift/ranges.shift_left.pass.cpp b/libcxx/test/std/algorithms/alg.modifying.operations/alg.shift/ranges.shift_left.pass.cpp
index 2e664e47a17e2f..485a729fea50f5 100644
--- a/libcxx/test/std/algorithms/alg.modifying.operations/alg.shift/ranges.shift_left.pass.cpp
+++ b/libcxx/test/std/algorithms/alg.modifying.operations/alg.shift/ranges.shift_left.pass.cpp
@@ -68,7 +68,7 @@ constexpr void test_iter_sent() {
}
// (range) overload
- for (size_t n = 0; n <= 15; ++n) {
+ for (size_t n = 0; n <= original.size(); ++n) {
for (size_t k = 0; k <= n + 2; ++k) {
auto begin = Iter(scratch.data());
auto end = Sent(Iter(scratch.data() + n));
>From e79f6430c5da5f95211ffb8df257bb436f8e63fd Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Sun, 3 Mar 2024 17:29:39 -0800
Subject: [PATCH 13/14] [libc++][ranges] refactor '__shift_left' to avoid
redundant iteration
---
libcxx/include/__algorithm/shift_left.h | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/libcxx/include/__algorithm/shift_left.h b/libcxx/include/__algorithm/shift_left.h
index 8df1bff87f0427..f609fc9cdc2537 100644
--- a/libcxx/include/__algorithm/shift_left.h
+++ b/libcxx/include/__algorithm/shift_left.h
@@ -27,30 +27,30 @@ _LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 20
template <class _AlgPolicy, class _Iter, class _Sent>
-inline _LIBCPP_HIDE_FROM_ABI constexpr pair<_Iter, _Iter>
-__shift_left(_Iter __first, _Sent __last, typename iterator_traits<_Iter>::difference_type __n) {
- _Iter __end = _IterOps<_AlgPolicy>::next(__first, __last);
-
+_LIBCPP_HIDE_FROM_ABI constexpr pair<_Iter, _Iter>
+__shift_left(_Iter __first, _Sent __last, typename _IterOps<_AlgPolicy>::template __difference_type<_Iter> __n) {
if (__n == 0) {
+ _Iter __end = _IterOps<_AlgPolicy>::next(__first, __last);
return {std::move(__first), std::move(__end)};
}
_Iter __m = __first;
- if constexpr (__has_random_access_iterator_category<_Iter>::value) {
- if (__n >= __end - __first) {
+ if constexpr (sized_sentinel_for<_Sent, _Iter>) {
+ auto __size = _IterOps<_AlgPolicy>::distance(__first, __last);
+ if (__n >= __size) {
return {std::move(__first), std::move(__first)};
}
- __m += __n;
+ _IterOps<_AlgPolicy>::advance(__m, __n);
} else {
for (; __n > 0; --__n) {
- if (__m == __end) {
+ if (__m == __last) {
return {std::move(__first), std::move(__first)};
}
++__m;
}
}
- _Iter __result = std::__move<_AlgPolicy>(__m, __end, __first).second;
+ _Iter __result = std::__move<_AlgPolicy>(__m, __last, __first).second;
return {std::move(__first), std::move(__result)};
}
>From 357f4eba5fa1157ff18c285aa108d345eef245e3 Mon Sep 17 00:00:00 2001
From: Xiaoyang Liu <siujoeng.lau at gmail.com>
Date: Sun, 3 Mar 2024 17:32:42 -0800
Subject: [PATCH 14/14] [libc++][ranges] refactor 'ranges::shift_left'
---
.../include/__algorithm/ranges_shift_left.h | 19 +++++++------------
1 file changed, 7 insertions(+), 12 deletions(-)
diff --git a/libcxx/include/__algorithm/ranges_shift_left.h b/libcxx/include/__algorithm/ranges_shift_left.h
index d9edf661d1d8ca..439d4955edfa60 100644
--- a/libcxx/include/__algorithm/ranges_shift_left.h
+++ b/libcxx/include/__algorithm/ranges_shift_left.h
@@ -36,24 +36,19 @@ namespace ranges {
namespace __shift_left {
struct __fn {
- template <class _Iter, class _Sent>
- _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter> static __shift_left_impl(
- _Iter __first, _Sent __last, iter_difference_t<_Iter> __n) {
+ template <permutable _Iter, sentinel_for<_Iter> _Sent>
+ _LIBCPP_HIDE_FROM_ABI static constexpr subrange<_Iter>
+ operator()(_Iter __first, _Sent __last, iter_difference_t<_Iter> __n) {
auto __ret = std::__shift_left<_RangeAlgPolicy>(std::move(__first), std::move(__last), std::move(__n));
return {std::move(__ret.first), std::move(__ret.second)};
}
- template <permutable _Iter, sentinel_for<_Iter> _Sent>
- _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter>
- operator()(_Iter __first, _Sent __last, iter_difference_t<_Iter> __n) const {
- return __shift_left_impl(std::move(__first), std::move(__last), std::move(__n));
- }
-
template <forward_range _Range>
requires permutable<iterator_t<_Range>>
- _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Range>
- operator()(_Range&& __range, range_difference_t<_Range> __n) const {
- return __shift_left_impl(ranges::begin(__range), ranges::end(__range), std::move(__n));
+ _LIBCPP_HIDE_FROM_ABI static constexpr borrowed_subrange_t<_Range>
+ operator()(_Range&& __range, range_difference_t<_Range> __n) {
+ auto __ret = std::__shift_left<_RangeAlgPolicy>(ranges::begin(__range), ranges::end(__range), std::move(__n));
+ return {std::move(__ret.first), std::move(__ret.second)};
}
};
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