240 lines
9.3 KiB
C++
240 lines
9.3 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___ALGORITHM_IS_PERMUTATION_H
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#define _LIBCPP___ALGORITHM_IS_PERMUTATION_H
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#include <__algorithm/comp.h>
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#include <__algorithm/iterator_operations.h>
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#include <__config>
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#include <__functional/identity.h>
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#include <__functional/invoke.h>
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#include <__iterator/concepts.h>
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#include <__iterator/distance.h>
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#include <__iterator/iterator_traits.h>
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#include <__iterator/next.h>
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#include <__utility/move.h>
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#include <type_traits>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class = void>
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struct _ConstTimeDistance : false_type {};
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#if _LIBCPP_STD_VER > 17
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template <class _Iter1, class _Sent1, class _Iter2, class _Sent2>
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struct _ConstTimeDistance<_Iter1, _Sent1, _Iter2, _Sent2, __enable_if_t<
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sized_sentinel_for<_Sent1, _Iter1> &&
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sized_sentinel_for<_Sent2, _Iter2>
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>> : true_type {};
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#else
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template <class _Iter1, class _Iter2>
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struct _ConstTimeDistance<_Iter1, _Iter1, _Iter2, _Iter2, __enable_if_t<
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is_same<typename iterator_traits<_Iter1>::iterator_category, random_access_iterator_tag>::value &&
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is_same<typename iterator_traits<_Iter2>::iterator_category, random_access_iterator_tag>::value
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> > : true_type {};
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#endif // _LIBCPP_STD_VER > 17
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// Internal functions
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// For each element in [f1, l1) see if there are the same number of equal elements in [f2, l2)
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template <class _AlgPolicy,
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class _Iter1, class _Sent1, class _Iter2, class _Sent2,
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class _Proj1, class _Proj2, class _Pred>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
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__is_permutation_impl(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
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_Pred&& __pred, _Proj1&& __proj1, _Proj2&& __proj2) {
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using _D1 = __iter_diff_t<_Iter1>;
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for (auto __i = __first1; __i != __last1; ++__i) {
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// Have we already counted the number of *__i in [f1, l1)?
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auto __match = __first1;
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for (; __match != __i; ++__match) {
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if (std::__invoke(__pred, std::__invoke(__proj1, *__match), std::__invoke(__proj1, *__i)))
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break;
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}
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if (__match == __i) {
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// Count number of *__i in [f2, l2)
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_D1 __c2 = 0;
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for (auto __j = __first2; __j != __last2; ++__j) {
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if (std::__invoke(__pred, std::__invoke(__proj1, *__i), std::__invoke(__proj2, *__j)))
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++__c2;
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}
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if (__c2 == 0)
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return false;
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// Count number of *__i in [__i, l1) (we can start with 1)
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_D1 __c1 = 1;
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for (auto __j = _IterOps<_AlgPolicy>::next(__i); __j != __last1; ++__j) {
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if (std::__invoke(__pred, std::__invoke(__proj1, *__i), std::__invoke(__proj1, *__j)))
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++__c1;
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}
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if (__c1 != __c2)
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return false;
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}
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}
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return true;
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}
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// 2+1 iterators, predicate. Not used by range algorithms.
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template <class _AlgPolicy, class _ForwardIterator1, class _Sentinel1, class _ForwardIterator2, class _BinaryPredicate>
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_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
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__is_permutation(_ForwardIterator1 __first1, _Sentinel1 __last1, _ForwardIterator2 __first2,
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_BinaryPredicate&& __pred) {
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// Shorten sequences as much as possible by lopping of any equal prefix.
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for (; __first1 != __last1; ++__first1, (void)++__first2) {
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if (!__pred(*__first1, *__first2))
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break;
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}
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if (__first1 == __last1)
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return true;
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// __first1 != __last1 && *__first1 != *__first2
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using _D1 = __iter_diff_t<_ForwardIterator1>;
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_D1 __l1 = _IterOps<_AlgPolicy>::distance(__first1, __last1);
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if (__l1 == _D1(1))
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return false;
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auto __last2 = _IterOps<_AlgPolicy>::next(__first2, __l1);
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return std::__is_permutation_impl<_AlgPolicy>(
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std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2),
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__pred, __identity(), __identity());
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}
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// 2+2 iterators, predicate, non-constant time `distance`.
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template <class _AlgPolicy,
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class _Iter1, class _Sent1, class _Iter2, class _Sent2,
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class _Proj1, class _Proj2, class _Pred>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
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__is_permutation(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
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_Pred&& __pred, _Proj1&& __proj1, _Proj2&& __proj2,
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/*_ConstTimeDistance=*/false_type) {
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// Shorten sequences as much as possible by lopping of any equal prefix.
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while (__first1 != __last1 && __first2 != __last2) {
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if (!std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
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break;
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++__first1;
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++__first2;
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}
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if (__first1 == __last1)
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return __first2 == __last2;
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if (__first2 == __last2) // Second range is shorter
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return false;
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using _D1 = __iter_diff_t<_Iter1>;
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_D1 __l1 = _IterOps<_AlgPolicy>::distance(__first1, __last1);
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using _D2 = __iter_diff_t<_Iter2>;
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_D2 __l2 = _IterOps<_AlgPolicy>::distance(__first2, __last2);
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if (__l1 != __l2)
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return false;
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return std::__is_permutation_impl<_AlgPolicy>(
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std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2),
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__pred, __proj1, __proj2);
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}
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// 2+2 iterators, predicate, specialization for constant-time `distance` call.
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template <class _AlgPolicy,
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class _Iter1, class _Sent1, class _Iter2, class _Sent2,
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class _Proj1, class _Proj2, class _Pred>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
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__is_permutation(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
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_Pred&& __pred, _Proj1&& __proj1, _Proj2&& __proj2,
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/*_ConstTimeDistance=*/true_type) {
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if (std::distance(__first1, __last1) != std::distance(__first2, __last2))
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return false;
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return std::__is_permutation<_AlgPolicy>(
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std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2),
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__pred, __proj1, __proj2,
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/*_ConstTimeDistance=*/false_type());
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}
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// 2+2 iterators, predicate
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template <class _AlgPolicy,
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class _Iter1, class _Sent1, class _Iter2, class _Sent2,
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class _Proj1, class _Proj2, class _Pred>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
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__is_permutation(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
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_Pred&& __pred, _Proj1&& __proj1, _Proj2&& __proj2) {
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return std::__is_permutation<_AlgPolicy>(
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std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2),
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__pred, __proj1, __proj2,
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_ConstTimeDistance<_Iter1, _Sent1, _Iter2, _Sent2>());
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}
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// Public interface
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// 2+1 iterators, predicate
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template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
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_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
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is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
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_BinaryPredicate __pred) {
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static_assert(__is_callable<_BinaryPredicate, decltype(*__first1), decltype(*__first2)>::value,
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"The predicate has to be callable");
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return std::__is_permutation<_ClassicAlgPolicy>(
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std::move(__first1), std::move(__last1), std::move(__first2), __pred);
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}
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// 2+1 iterators
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template <class _ForwardIterator1, class _ForwardIterator2>
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_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
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is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2) {
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using __v1 = __iter_value_type<_ForwardIterator1>;
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using __v2 = __iter_value_type<_ForwardIterator2>;
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return std::is_permutation(__first1, __last1, __first2, __equal_to<__v1, __v2>());
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}
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#if _LIBCPP_STD_VER > 11
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// 2+2 iterators
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template <class _ForwardIterator1, class _ForwardIterator2>
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_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
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is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
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_ForwardIterator2 __last2) {
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using __v1 = __iter_value_type<_ForwardIterator1>;
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using __v2 = __iter_value_type<_ForwardIterator2>;
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return std::__is_permutation<_ClassicAlgPolicy>(
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std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2),
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__equal_to<__v1, __v2>(), __identity(), __identity());
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}
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// 2+2 iterators, predicate
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template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
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_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
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is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
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_ForwardIterator2 __last2, _BinaryPredicate __pred) {
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static_assert(__is_callable<_BinaryPredicate, decltype(*__first1), decltype(*__first2)>::value,
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"The predicate has to be callable");
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return std::__is_permutation<_ClassicAlgPolicy>(
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std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2),
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__pred, __identity(), __identity());
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}
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#endif // _LIBCPP_STD_VER > 11
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___ALGORITHM_IS_PERMUTATION_H
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