| //===----------------------------------------------------------------------===// |
| // |
| // 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_PREV_PERMUTATION_H |
| #define _LIBCPP___ALGORITHM_PREV_PERMUTATION_H |
| |
| #include <__algorithm/comp.h> |
| #include <__algorithm/comp_ref_type.h> |
| #include <__algorithm/iterator_operations.h> |
| #include <__algorithm/reverse.h> |
| #include <__config> |
| #include <__iterator/iterator_traits.h> |
| #include <__utility/move.h> |
| #include <__utility/pair.h> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_PUSH_MACROS |
| #include <__undef_macros> |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| template <class _AlgPolicy, class _Compare, class _BidirectionalIterator, class _Sentinel> |
| _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_BidirectionalIterator, bool> |
| __prev_permutation(_BidirectionalIterator __first, _Sentinel __last, _Compare&& __comp) { |
| using _Result = pair<_BidirectionalIterator, bool>; |
| |
| _BidirectionalIterator __last_iter = _IterOps<_AlgPolicy>::next(__first, __last); |
| _BidirectionalIterator __i = __last_iter; |
| if (__first == __last || __first == --__i) |
| return _Result(std::move(__last_iter), false); |
| |
| while (true) { |
| _BidirectionalIterator __ip1 = __i; |
| if (__comp(*__ip1, *--__i)) { |
| _BidirectionalIterator __j = __last_iter; |
| while (!__comp(*--__j, *__i)) |
| ; |
| _IterOps<_AlgPolicy>::iter_swap(__i, __j); |
| std::__reverse<_AlgPolicy>(__ip1, __last_iter); |
| return _Result(std::move(__last_iter), true); |
| } |
| if (__i == __first) { |
| std::__reverse<_AlgPolicy>(__first, __last_iter); |
| return _Result(std::move(__last_iter), false); |
| } |
| } |
| } |
| |
| template <class _BidirectionalIterator, class _Compare> |
| inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool |
| prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp) { |
| return std::__prev_permutation<_ClassicAlgPolicy>( |
| std::move(__first), std::move(__last), static_cast<__comp_ref_type<_Compare> >(__comp)) |
| .second; |
| } |
| |
| template <class _BidirectionalIterator> |
| inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool |
| prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last) { |
| return std::prev_permutation(__first, __last, __less<>()); |
| } |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| _LIBCPP_POP_MACROS |
| |
| #endif // _LIBCPP___ALGORITHM_PREV_PERMUTATION_H |