v1/__algorithm/mismatch.h

0001 // -*- C++ -*-
0002 //===----------------------------------------------------------------------===//
0003 //
0004 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0005 // See https://llvm.org/LICENSE.txt for license information.
0006 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0007 //
0008 //===----------------------------------------------------------------------===//
0009
0010 #ifndef _LIBCPP___ALGORITHM_MISMATCH_H
0011 #define _LIBCPP___ALGORITHM_MISMATCH_H
0012
0013 #include <__algorithm/comp.h>
0014 #include <__algorithm/min.h>
0015 #include <__algorithm/simd_utils.h>
0016 #include <__algorithm/unwrap_iter.h>
0017 #include <__config>
0018 #include <__cstddef/size_t.h>
0019 #include <__functional/identity.h>
0020 #include <__iterator/aliasing_iterator.h>
0021 #include <__iterator/iterator_traits.h>
0022 #include <__type_traits/desugars_to.h>
0023 #include <__type_traits/enable_if.h>
0024 #include <__type_traits/invoke.h>
0025 #include <__type_traits/is_constant_evaluated.h>
0026 #include <__type_traits/is_equality_comparable.h>
0027 #include <__type_traits/is_integral.h>
0028 #include <__utility/move.h>
0029 #include <__utility/pair.h>
0030
0031 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0032 #  pragma GCC system_header
0033 #endif
0034
0035 _LIBCPP_PUSH_MACROS
0036 #include <__undef_macros>
0037
0038 _LIBCPP_BEGIN_NAMESPACE_STD
0039
0040 template <class _Iter1, class _Sent1, class _Iter2, class _Pred, class _Proj1, class _Proj2>
0041 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_Iter1, _Iter2>
0042 __mismatch_loop(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Pred& __pred, _Proj1& __proj1, _Proj2& __proj2) {
0043   while (__first1 != __last1) {
0044     if (!std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
0045       break;
0046     ++__first1;
0047     ++__first2;
0048   }
0049   return std::make_pair(std::move(__first1), std::move(__first2));
0050 }
0051
0052 template <class _Iter1, class _Sent1, class _Iter2, class _Pred, class _Proj1, class _Proj2>
0053 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_Iter1, _Iter2>
0054 __mismatch(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Pred& __pred, _Proj1& __proj1, _Proj2& __proj2) {
0055   return std::__mismatch_loop(__first1, __last1, __first2, __pred, __proj1, __proj2);
0056 }
0057
0058 #if _LIBCPP_VECTORIZE_ALGORITHMS
0059
0060 template <class _Iter>
0061 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_Iter, _Iter>
0062 __mismatch_vectorized(_Iter __first1, _Iter __last1, _Iter __first2) {
0063   using __value_type              = __iter_value_type<_Iter>;
0064   constexpr size_t __unroll_count = 4;
0065   constexpr size_t __vec_size     = __native_vector_size<__value_type>;
0066   using __vec                     = __simd_vector<__value_type, __vec_size>;
0067
0068   if (!__libcpp_is_constant_evaluated()) {
0069     auto __orig_first1 = __first1;
0070     auto __last2       = __first2 + (__last1 - __first1);
0071     while (static_cast<size_t>(__last1 - __first1) >= __unroll_count * __vec_size) [[__unlikely__]] {
0072       __vec __lhs[__unroll_count];
0073       __vec __rhs[__unroll_count];
0074
0075       for (size_t __i = 0; __i != __unroll_count; ++__i) {
0076         __lhs[__i] = std::__load_vector<__vec>(__first1 + __i * __vec_size);
0077         __rhs[__i] = std::__load_vector<__vec>(__first2 + __i * __vec_size);
0078       }
0079
0080       for (size_t __i = 0; __i != __unroll_count; ++__i) {
0081         if (auto __cmp_res = __lhs[__i] == __rhs[__i]; !std::__all_of(__cmp_res)) {
0082           auto __offset = __i * __vec_size + std::__find_first_not_set(__cmp_res);
0083           return {__first1 + __offset, __first2 + __offset};
0084         }
0085       }
0086
0087       __first1 += __unroll_count * __vec_size;
0088       __first2 += __unroll_count * __vec_size;
0089     }
0090
0091     // check the remaining 0-3 vectors
0092     while (static_cast<size_t>(__last1 - __first1) >= __vec_size) {
0093       if (auto __cmp_res = std::__load_vector<__vec>(__first1) == std::__load_vector<__vec>(__first2);
0094           !std::__all_of(__cmp_res)) {
0095         auto __offset = std::__find_first_not_set(__cmp_res);
0096         return {__first1 + __offset, __first2 + __offset};
0097       }
0098       __first1 += __vec_size;
0099       __first2 += __vec_size;
0100     }
0101
0102     if (__last1 - __first1 == 0)
0103       return {__first1, __first2};
0104
0105     // Check if we can load elements in front of the current pointer. If that's the case load a vector at
0106     // (last - vector_size) to check the remaining elements
0107     if (static_cast<size_t>(__first1 - __orig_first1) >= __vec_size) {
0108       __first1 = __last1 - __vec_size;
0109       __first2 = __last2 - __vec_size;
0110       auto __offset =
0111           std::__find_first_not_set(std::__load_vector<__vec>(__first1) == std::__load_vector<__vec>(__first2));
0112       return {__first1 + __offset, __first2 + __offset};
0113     } // else loop over the elements individually
0114   }
0115
0116   __equal_to __pred;
0117   __identity __proj;
0118   return std::__mismatch_loop(__first1, __last1, __first2, __pred, __proj, __proj);
0119 }
0120
0121 template <class _Tp,
0122           class _Pred,
0123           class _Proj1,
0124           class _Proj2,
0125           __enable_if_t<is_integral<_Tp>::value && __desugars_to_v<__equal_tag, _Pred, _Tp, _Tp> &&
0126                             __is_identity<_Proj1>::value && __is_identity<_Proj2>::value,
0127                         int> = 0>
0128 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_Tp*, _Tp*>
0129 __mismatch(_Tp* __first1, _Tp* __last1, _Tp* __first2, _Pred&, _Proj1&, _Proj2&) {
0130   return std::__mismatch_vectorized(__first1, __last1, __first2);
0131 }
0132
0133 template <class _Tp,
0134           class _Pred,
0135           class _Proj1,
0136           class _Proj2,
0137           __enable_if_t<!is_integral<_Tp>::value && __desugars_to_v<__equal_tag, _Pred, _Tp, _Tp> &&
0138                             __is_identity<_Proj1>::value && __is_identity<_Proj2>::value &&
0139                             __can_map_to_integer_v<_Tp> && __libcpp_is_trivially_equality_comparable<_Tp, _Tp>::value,
0140                         int> = 0>
0141 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_Tp*, _Tp*>
0142 __mismatch(_Tp* __first1, _Tp* __last1, _Tp* __first2, _Pred& __pred, _Proj1& __proj1, _Proj2& __proj2) {
0143   if (__libcpp_is_constant_evaluated()) {
0144     return std::__mismatch_loop(__first1, __last1, __first2, __pred, __proj1, __proj2);
0145   } else {
0146     using _Iter = __aliasing_iterator<_Tp*, __get_as_integer_type_t<_Tp>>;
0147     auto __ret  = std::__mismatch_vectorized(_Iter(__first1), _Iter(__last1), _Iter(__first2));
0148     return {__ret.first.__base(), __ret.second.__base()};
0149   }
0150 }
0151 #endif // _LIBCPP_VECTORIZE_ALGORITHMS
0152
0153 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
0154 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InputIterator1, _InputIterator2>
0155 mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred) {
0156   __identity __proj;
0157   auto __res = std::__mismatch(
0158       std::__unwrap_iter(__first1), std::__unwrap_iter(__last1), std::__unwrap_iter(__first2), __pred, __proj, __proj);
0159   return std::make_pair(std::__rewrap_iter(__first1, __res.first), std::__rewrap_iter(__first2, __res.second));
0160 }
0161
0162 template <class _InputIterator1, class _InputIterator2>
0163 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InputIterator1, _InputIterator2>
0164 mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2) {
0165   return std::mismatch(__first1, __last1, __first2, __equal_to());
0166 }
0167
0168 #if _LIBCPP_STD_VER >= 14
0169 template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Pred, class _Proj1, class _Proj2>
0170 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_Iter1, _Iter2> __mismatch(
0171     _Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2, _Pred& __pred, _Proj1& __proj1, _Proj2& __proj2) {
0172   while (__first1 != __last1 && __first2 != __last2) {
0173     if (!std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
0174       break;
0175     ++__first1;
0176     ++__first2;
0177   }
0178   return {std::move(__first1), std::move(__first2)};
0179 }
0180
0181 template <class _Tp, class _Pred, class _Proj1, class _Proj2>
0182 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_Tp*, _Tp*>
0183 __mismatch(_Tp* __first1, _Tp* __last1, _Tp* __first2, _Tp* __last2, _Pred& __pred, _Proj1& __proj1, _Proj2& __proj2) {
0184   auto __len = std::min(__last1 - __first1, __last2 - __first2);
0185   return std::__mismatch(__first1, __first1 + __len, __first2, __pred, __proj1, __proj2);
0186 }
0187
0188 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
0189 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InputIterator1, _InputIterator2>
0190 mismatch(_InputIterator1 __first1,
0191          _InputIterator1 __last1,
0192          _InputIterator2 __first2,
0193          _InputIterator2 __last2,
0194          _BinaryPredicate __pred) {
0195   __identity __proj;
0196   auto __res = std::__mismatch(
0197       std::__unwrap_iter(__first1),
0198       std::__unwrap_iter(__last1),
0199       std::__unwrap_iter(__first2),
0200       std::__unwrap_iter(__last2),
0201       __pred,
0202       __proj,
0203       __proj);
0204   return {std::__rewrap_iter(__first1, __res.first), std::__rewrap_iter(__first2, __res.second)};
0205 }
0206
0207 template <class _InputIterator1, class _InputIterator2>
0208 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InputIterator1, _InputIterator2>
0209 mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) {
0210   return std::mismatch(__first1, __last1, __first2, __last2, __equal_to());
0211 }
0212 #endif
0213
0214 _LIBCPP_END_NAMESPACE_STD
0215
0216 _LIBCPP_POP_MACROS
0217
0218 #endif // _LIBCPP___ALGORITHM_MISMATCH_H