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92 lines
3.7 KiB
C++
92 lines
3.7 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_COUNT_H
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#define _LIBCPP___ALGORITHM_COUNT_H
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#include <__algorithm/iterator_operations.h>
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#include <__algorithm/min.h>
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#include <__bit/invert_if.h>
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#include <__bit/popcount.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 <__fwd/bit_reference.h>
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#include <__iterator/iterator_traits.h>
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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_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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// generic implementation
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template <class _AlgPolicy, class _Iter, class _Sent, class _Tp, class _Proj>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 typename _IterOps<_AlgPolicy>::template __difference_type<_Iter>
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__count(_Iter __first, _Sent __last, const _Tp& __value, _Proj& __proj) {
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typename _IterOps<_AlgPolicy>::template __difference_type<_Iter> __r(0);
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for (; __first != __last; ++__first)
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if (std::__invoke(__proj, *__first) == __value)
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++__r;
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return __r;
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}
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// __bit_iterator implementation
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template <bool _ToCount, class _Cp, bool _IsConst>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 typename __bit_iterator<_Cp, _IsConst>::difference_type
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__count_bool(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n) {
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using _It = __bit_iterator<_Cp, _IsConst>;
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using __storage_type = typename _It::__storage_type;
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using difference_type = typename _It::difference_type;
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const int __bits_per_word = _It::__bits_per_word;
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difference_type __r = 0;
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// do first partial word
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if (__first.__ctz_ != 0) {
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__storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
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__storage_type __dn = std::min(__clz_f, __n);
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__storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
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__r = std::__libcpp_popcount(std::__invert_if<!_ToCount>(*__first.__seg_) & __m);
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__n -= __dn;
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++__first.__seg_;
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}
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// do middle whole words
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for (; __n >= __bits_per_word; ++__first.__seg_, __n -= __bits_per_word)
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__r += std::__libcpp_popcount(std::__invert_if<!_ToCount>(*__first.__seg_));
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// do last partial word
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if (__n > 0) {
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__storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
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__r += std::__libcpp_popcount(std::__invert_if<!_ToCount>(*__first.__seg_) & __m);
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}
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return __r;
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}
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template <class, class _Cp, bool _IsConst, class _Tp, class _Proj, __enable_if_t<__is_identity<_Proj>::value, int> = 0>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __iter_diff_t<__bit_iterator<_Cp, _IsConst> >
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__count(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, const _Tp& __value, _Proj&) {
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if (__value)
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return std::__count_bool<true>(__first, static_cast<typename _Cp::size_type>(__last - __first));
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return std::__count_bool<false>(__first, static_cast<typename _Cp::size_type>(__last - __first));
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}
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template <class _InputIterator, class _Tp>
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_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __iter_diff_t<_InputIterator>
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count(_InputIterator __first, _InputIterator __last, const _Tp& __value) {
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__identity __proj;
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return std::__count<_ClassicAlgPolicy>(__first, __last, __value, __proj);
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}
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___ALGORITHM_COUNT_H
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