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_EQUAL_RANGE_H 10 #define _LIBCPP___ALGORITHM_EQUAL_RANGE_H 11 12 #include <__algorithm/comp.h> 13 #include <__algorithm/comp_ref_type.h> 14 #include <__algorithm/half_positive.h> 15 #include <__algorithm/lower_bound.h> 16 #include <__algorithm/upper_bound.h> 17 #include <__config> 18 #include <iterator> 19 20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 21 #pragma GCC system_header 22 #endif 23 24 _LIBCPP_BEGIN_NAMESPACE_STD 25 26 template <class _Compare, class _ForwardIterator, class _Tp> 27 _LIBCPP_CONSTEXPR_AFTER_CXX17 pair<_ForwardIterator, _ForwardIterator> 28 __equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp) 29 { 30 typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type; 31 difference_type __len = _VSTD::distance(__first, __last); 32 while (__len != 0) 33 { 34 difference_type __l2 = _VSTD::__half_positive(__len); 35 _ForwardIterator __m = __first; 36 _VSTD::advance(__m, __l2); 37 if (__comp(*__m, __value_)) 38 { 39 __first = ++__m; 40 __len -= __l2 + 1; 41 } 42 else if (__comp(__value_, *__m)) 43 { 44 __last = __m; 45 __len = __l2; 46 } 47 else 48 { 49 _ForwardIterator __mp1 = __m; 50 return pair<_ForwardIterator, _ForwardIterator> 51 ( 52 _VSTD::__lower_bound<_Compare>(__first, __m, __value_, __comp), 53 _VSTD::__upper_bound<_Compare>(++__mp1, __last, __value_, __comp) 54 ); 55 } 56 } 57 return pair<_ForwardIterator, _ForwardIterator>(__first, __first); 58 } 59 60 template <class _ForwardIterator, class _Tp, class _Compare> 61 _LIBCPP_NODISCARD_EXT inline 62 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 63 pair<_ForwardIterator, _ForwardIterator> 64 equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp) 65 { 66 typedef typename __comp_ref_type<_Compare>::type _Comp_ref; 67 return _VSTD::__equal_range<_Comp_ref>(__first, __last, __value_, __comp); 68 } 69 70 template <class _ForwardIterator, class _Tp> 71 _LIBCPP_NODISCARD_EXT inline 72 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 73 pair<_ForwardIterator, _ForwardIterator> 74 equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_) 75 { 76 return _VSTD::equal_range(__first, __last, __value_, 77 __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>()); 78 } 79 80 _LIBCPP_END_NAMESPACE_STD 81 82 #endif // _LIBCPP___ALGORITHM_EQUAL_RANGE_H 83