libcxx/include/__algorithm/unique.h

   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_UNIQUE_H
  10 #define _LIBCPP___ALGORITHM_UNIQUE_H
  11
  12 #include <__algorithm/adjacent_find.h>
  13 #include <__algorithm/comp.h>
  14 #include <__algorithm/iterator_operations.h>
  15 #include <__config>
  16 #include <__functional/identity.h>
  17 #include <__iterator/iterator_traits.h>
  18 #include <__utility/move.h>
  19 #include <__utility/pair.h>
  20
  21 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  22 #  pragma GCC system_header
  23 #endif
  24
  25 _LIBCPP_PUSH_MACROS
  26 #include <__undef_macros>
  27
  28 _LIBCPP_BEGIN_NAMESPACE_STD
  29
  30 // unique
  31
  32 template <class _AlgPolicy, class _Iter, class _Sent, class _BinaryPredicate>
  33 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 std::pair<_Iter, _Iter>
  34 __unique(_Iter __first, _Sent __last, _BinaryPredicate&& __pred) {
  35   __identity __proj;
  36   __first = std::__adjacent_find(__first, __last, __pred, __proj);
  37   if (__first != __last) {
  38     // ...  a  a  ?  ...
  39     //      f     i
  40     _Iter __i = __first;
  41     for (++__i; ++__i != __last;)
  42       if (!__pred(*__first, *__i))
  43         *++__first = _IterOps<_AlgPolicy>::__iter_move(__i);
  44     ++__first;
  45     return std::pair<_Iter, _Iter>(std::move(__first), std::move(__i));
  46   }
  47   return std::pair<_Iter, _Iter>(__first, __first);
  48 }
  49
  50 template <class _ForwardIterator, class _BinaryPredicate>
  51 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
  52 unique(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred) {
  53   return std::__unique<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __pred).first;
  54 }
  55
  56 template <class _ForwardIterator>
  57 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
  58 unique(_ForwardIterator __first, _ForwardIterator __last) {
  59   return std::unique(__first, __last, __equal_to());
  60 }
  61
  62 _LIBCPP_END_NAMESPACE_STD
  63
  64 _LIBCPP_POP_MACROS
  65
  66 #endif // _LIBCPP___ALGORITHM_UNIQUE_H