libcxx/include/__algorithm/equal.h

   1 // -*- C++ -*-
   2 //===----------------------------------------------------------------------===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #ifndef _LIBCPP___ALGORITHM_EQUAL_H
  11 #define _LIBCPP___ALGORITHM_EQUAL_H
  12
  13 #include <__algorithm/comp.h>
  14 #include <__algorithm/unwrap_iter.h>
  15 #include <__config>
  16 #include <__functional/identity.h>
  17 #include <__iterator/distance.h>
  18 #include <__iterator/iterator_traits.h>
  19 #include <__string/constexpr_c_functions.h>
  20 #include <__type_traits/desugars_to.h>
  21 #include <__type_traits/enable_if.h>
  22 #include <__type_traits/invoke.h>
  23 #include <__type_traits/is_equality_comparable.h>
  24 #include <__type_traits/is_volatile.h>
  25 #include <__utility/move.h>
  26
  27 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  28 #  pragma GCC system_header
  29 #endif
  30
  31 _LIBCPP_PUSH_MACROS
  32 #include <__undef_macros>
  33
  34 _LIBCPP_BEGIN_NAMESPACE_STD
  35
  36 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
  37 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __equal_iter_impl(
  38     _InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate& __pred) {
  39   for (; __first1 != __last1; ++__first1, (void)++__first2)
  40     if (!__pred(*__first1, *__first2))
  41       return false;
  42   return true;
  43 }
  44
  45 template <class _Tp,
  46           class _Up,
  47           class _BinaryPredicate,
  48           __enable_if_t<__desugars_to_v<__equal_tag, _BinaryPredicate, _Tp, _Up> && !is_volatile<_Tp>::value &&
  49                             !is_volatile<_Up>::value && __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value,
  50                         int> = 0>
  51 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
  52 __equal_iter_impl(_Tp* __first1, _Tp* __last1, _Up* __first2, _BinaryPredicate&) {
  53   return std::__constexpr_memcmp_equal(__first1, __first2, __element_count(__last1 - __first1));
  54 }
  55
  56 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
  57 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
  58 equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred) {
  59   return std::__equal_iter_impl(
  60       std::__unwrap_iter(__first1), std::__unwrap_iter(__last1), std::__unwrap_iter(__first2), __pred);
  61 }
  62
  63 template <class _InputIterator1, class _InputIterator2>
  64 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
  65 equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2) {
  66   return std::equal(__first1, __last1, __first2, __equal_to());
  67 }
  68
  69 #if _LIBCPP_STD_VER >= 14
  70
  71 template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Pred, class _Proj1, class _Proj2>
  72 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __equal_impl(
  73     _Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2, _Pred& __comp, _Proj1& __proj1, _Proj2& __proj2) {
  74   while (__first1 != __last1 && __first2 != __last2) {
  75     if (!std::__invoke(__comp, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
  76       return false;
  77     ++__first1;
  78     ++__first2;
  79   }
  80   return __first1 == __last1 && __first2 == __last2;
  81 }
  82
  83 template <class _Tp,
  84           class _Up,
  85           class _Pred,
  86           class _Proj1,
  87           class _Proj2,
  88           __enable_if_t<__desugars_to_v<__equal_tag, _Pred, _Tp, _Up> && __is_identity<_Proj1>::value &&
  89                             __is_identity<_Proj2>::value && !is_volatile<_Tp>::value && !is_volatile<_Up>::value &&
  90                             __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value,
  91                         int> = 0>
  92 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
  93 __equal_impl(_Tp* __first1, _Tp* __last1, _Up* __first2, _Up*, _Pred&, _Proj1&, _Proj2&) {
  94   return std::__constexpr_memcmp_equal(__first1, __first2, __element_count(__last1 - __first1));
  95 }
  96
  97 template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
  98 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
  99 equal(_InputIterator1 __first1,
 100       _InputIterator1 __last1,
 101       _InputIterator2 __first2,
 102       _InputIterator2 __last2,
 103       _BinaryPredicate __pred) {
 104   if constexpr (__has_random_access_iterator_category<_InputIterator1>::value &&
 105                 __has_random_access_iterator_category<_InputIterator2>::value) {
 106     if (std::distance(__first1, __last1) != std::distance(__first2, __last2))
 107       return false;
 108   }
 109   __identity __proj;
 110   return std::__equal_impl(
 111       std::__unwrap_iter(__first1),
 112       std::__unwrap_iter(__last1),
 113       std::__unwrap_iter(__first2),
 114       std::__unwrap_iter(__last2),
 115       __pred,
 116       __proj,
 117       __proj);
 118 }
 119
 120 template <class _InputIterator1, class _InputIterator2>
 121 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 122 equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) {
 123   return std::equal(__first1, __last1, __first2, __last2, __equal_to());
 124 }
 125
 126 #endif // _LIBCPP_STD_VER >= 14
 127
 128 _LIBCPP_END_NAMESPACE_STD
 129
 130 _LIBCPP_POP_MACROS
 131
 132 #endif // _LIBCPP___ALGORITHM_EQUAL_H