| //===----------------------------------------------------------------------===// |
| // |
| // 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_INPLACE_MERGE_H |
| #define _LIBCPP___ALGORITHM_INPLACE_MERGE_H |
| |
| #include <__config> |
| #include <__algorithm/comp_ref_type.h> |
| #include <__algorithm/comp.h> |
| #include <__algorithm/lower_bound.h> |
| #include <__algorithm/min.h> |
| #include <__algorithm/move.h> |
| #include <__algorithm/rotate.h> |
| #include <__algorithm/upper_bound.h> |
| #include <__iterator/iterator_traits.h> |
| #include <__utility/swap.h> |
| #include <memory> |
| |
| #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 _Predicate> |
| class __invert // invert the sense of a comparison |
| { |
| private: |
| _Predicate __p_; |
| public: |
| _LIBCPP_INLINE_VISIBILITY __invert() {} |
| |
| _LIBCPP_INLINE_VISIBILITY |
| explicit __invert(_Predicate __p) : __p_(__p) {} |
| |
| template <class _T1> |
| _LIBCPP_INLINE_VISIBILITY |
| bool operator()(const _T1& __x) {return !__p_(__x);} |
| |
| template <class _T1, class _T2> |
| _LIBCPP_INLINE_VISIBILITY |
| bool operator()(const _T1& __x, const _T2& __y) {return __p_(__y, __x);} |
| }; |
| |
| template <class _Compare, class _InputIterator1, class _InputIterator2, |
| class _OutputIterator> |
| void __half_inplace_merge(_InputIterator1 __first1, _InputIterator1 __last1, |
| _InputIterator2 __first2, _InputIterator2 __last2, |
| _OutputIterator __result, _Compare __comp) |
| { |
| for (; __first1 != __last1; ++__result) |
| { |
| if (__first2 == __last2) |
| { |
| _VSTD::move(__first1, __last1, __result); |
| return; |
| } |
| |
| if (__comp(*__first2, *__first1)) |
| { |
| *__result = _VSTD::move(*__first2); |
| ++__first2; |
| } |
| else |
| { |
| *__result = _VSTD::move(*__first1); |
| ++__first1; |
| } |
| } |
| // __first2 through __last2 are already in the right spot. |
| } |
| |
| template <class _Compare, class _BidirectionalIterator> |
| void |
| __buffered_inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last, |
| _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1, |
| typename iterator_traits<_BidirectionalIterator>::difference_type __len2, |
| typename iterator_traits<_BidirectionalIterator>::value_type* __buff) |
| { |
| typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type; |
| __destruct_n __d(0); |
| unique_ptr<value_type, __destruct_n&> __h2(__buff, __d); |
| if (__len1 <= __len2) |
| { |
| value_type* __p = __buff; |
| for (_BidirectionalIterator __i = __first; __i != __middle; __d.template __incr<value_type>(), (void) ++__i, (void) ++__p) |
| ::new ((void*)__p) value_type(_VSTD::move(*__i)); |
| _VSTD::__half_inplace_merge<_Compare>(__buff, __p, __middle, __last, __first, __comp); |
| } |
| else |
| { |
| value_type* __p = __buff; |
| for (_BidirectionalIterator __i = __middle; __i != __last; __d.template __incr<value_type>(), (void) ++__i, (void) ++__p) |
| ::new ((void*)__p) value_type(_VSTD::move(*__i)); |
| typedef reverse_iterator<_BidirectionalIterator> _RBi; |
| typedef reverse_iterator<value_type*> _Rv; |
| typedef __invert<_Compare> _Inverted; |
| _VSTD::__half_inplace_merge<_Inverted>(_Rv(__p), _Rv(__buff), |
| _RBi(__middle), _RBi(__first), |
| _RBi(__last), _Inverted(__comp)); |
| } |
| } |
| |
| template <class _Compare, class _BidirectionalIterator> |
| void |
| __inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last, |
| _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1, |
| typename iterator_traits<_BidirectionalIterator>::difference_type __len2, |
| typename iterator_traits<_BidirectionalIterator>::value_type* __buff, ptrdiff_t __buff_size) |
| { |
| typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type; |
| while (true) |
| { |
| // if __middle == __last, we're done |
| if (__len2 == 0) |
| return; |
| if (__len1 <= __buff_size || __len2 <= __buff_size) |
| return _VSTD::__buffered_inplace_merge<_Compare> |
| (__first, __middle, __last, __comp, __len1, __len2, __buff); |
| // shrink [__first, __middle) as much as possible (with no moves), returning if it shrinks to 0 |
| for (; true; ++__first, (void) --__len1) |
| { |
| if (__len1 == 0) |
| return; |
| if (__comp(*__middle, *__first)) |
| break; |
| } |
| // __first < __middle < __last |
| // *__first > *__middle |
| // partition [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last) such that |
| // all elements in: |
| // [__first, __m1) <= [__middle, __m2) |
| // [__middle, __m2) < [__m1, __middle) |
| // [__m1, __middle) <= [__m2, __last) |
| // and __m1 or __m2 is in the middle of its range |
| _BidirectionalIterator __m1; // "median" of [__first, __middle) |
| _BidirectionalIterator __m2; // "median" of [__middle, __last) |
| difference_type __len11; // distance(__first, __m1) |
| difference_type __len21; // distance(__middle, __m2) |
| // binary search smaller range |
| if (__len1 < __len2) |
| { // __len >= 1, __len2 >= 2 |
| __len21 = __len2 / 2; |
| __m2 = __middle; |
| _VSTD::advance(__m2, __len21); |
| __m1 = _VSTD::__upper_bound<_Compare>(__first, __middle, *__m2, __comp); |
| __len11 = _VSTD::distance(__first, __m1); |
| } |
| else |
| { |
| if (__len1 == 1) |
| { // __len1 >= __len2 && __len2 > 0, therefore __len2 == 1 |
| // It is known *__first > *__middle |
| swap(*__first, *__middle); |
| return; |
| } |
| // __len1 >= 2, __len2 >= 1 |
| __len11 = __len1 / 2; |
| __m1 = __first; |
| _VSTD::advance(__m1, __len11); |
| __m2 = _VSTD::__lower_bound<_Compare>(__middle, __last, *__m1, __comp); |
| __len21 = _VSTD::distance(__middle, __m2); |
| } |
| difference_type __len12 = __len1 - __len11; // distance(__m1, __middle) |
| difference_type __len22 = __len2 - __len21; // distance(__m2, __last) |
| // [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last) |
| // swap middle two partitions |
| __middle = _VSTD::rotate(__m1, __middle, __m2); |
| // __len12 and __len21 now have swapped meanings |
| // merge smaller range with recursive call and larger with tail recursion elimination |
| if (__len11 + __len21 < __len12 + __len22) |
| { |
| _VSTD::__inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size); |
| // _VSTD::__inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size); |
| __first = __middle; |
| __middle = __m2; |
| __len1 = __len12; |
| __len2 = __len22; |
| } |
| else |
| { |
| _VSTD::__inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size); |
| // _VSTD::__inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size); |
| __last = __middle; |
| __middle = __m1; |
| __len1 = __len11; |
| __len2 = __len21; |
| } |
| } |
| } |
| |
| template <class _BidirectionalIterator, class _Compare> |
| inline _LIBCPP_INLINE_VISIBILITY |
| void |
| inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last, |
| _Compare __comp) |
| { |
| typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type; |
| typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type; |
| difference_type __len1 = _VSTD::distance(__first, __middle); |
| difference_type __len2 = _VSTD::distance(__middle, __last); |
| difference_type __buf_size = _VSTD::min(__len1, __len2); |
| pair<value_type*, ptrdiff_t> __buf = _VSTD::get_temporary_buffer<value_type>(__buf_size); |
| unique_ptr<value_type, __return_temporary_buffer> __h(__buf.first); |
| typedef typename __comp_ref_type<_Compare>::type _Comp_ref; |
| return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __comp, __len1, __len2, |
| __buf.first, __buf.second); |
| } |
| |
| template <class _BidirectionalIterator> |
| inline _LIBCPP_INLINE_VISIBILITY |
| void |
| inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last) |
| { |
| _VSTD::inplace_merge(__first, __middle, __last, |
| __less<typename iterator_traits<_BidirectionalIterator>::value_type>()); |
| } |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| _LIBCPP_POP_MACROS |
| |
| #endif // _LIBCPP___ALGORITHM_INPLACE_MERGE_H |
