1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___ALGORITHM_REVERSE_H 10 #define _LIBCPP___ALGORITHM_REVERSE_H 11 12 #include <__algorithm/iter_swap.h> 13 #include <__config> 14 #include <__iterator/iterator_traits.h> 15 16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 17 #pragma GCC system_header 18 #endif 19 20 _LIBCPP_BEGIN_NAMESPACE_STD 21 22 template <class _BidirectionalIterator> 23 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 24 void 25 __reverse(_BidirectionalIterator __first, _BidirectionalIterator __last, bidirectional_iterator_tag) 26 { 27 while (__first != __last) 28 { 29 if (__first == --__last) 30 break; 31 _VSTD::iter_swap(__first, __last); 32 ++__first; 33 } 34 } 35 36 template <class _RandomAccessIterator> 37 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 38 void 39 __reverse(_RandomAccessIterator __first, _RandomAccessIterator __last, random_access_iterator_tag) 40 { 41 if (__first != __last) 42 for (; __first < --__last; ++__first) 43 _VSTD::iter_swap(__first, __last); 44 } 45 46 template <class _BidirectionalIterator> 47 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 48 void 49 reverse(_BidirectionalIterator __first, _BidirectionalIterator __last) 50 { 51 _VSTD::__reverse(__first, __last, typename iterator_traits<_BidirectionalIterator>::iterator_category()); 52 } 53 54 _LIBCPP_END_NAMESPACE_STD 55 56 #endif // _LIBCPP___ALGORITHM_REVERSE_H 57