1fe6060f1SDimitry Andric // -*- C++ -*- 2fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 3fe6060f1SDimitry Andric // 4fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 6fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7fe6060f1SDimitry Andric // 8fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 9fe6060f1SDimitry Andric 10fe6060f1SDimitry Andric #ifndef _LIBCPP___ALGORITHM_COUNT_H 11fe6060f1SDimitry Andric #define _LIBCPP___ALGORITHM_COUNT_H 12fe6060f1SDimitry Andric 13*5f757f3fSDimitry Andric #include <__algorithm/iterator_operations.h> 14*5f757f3fSDimitry Andric #include <__algorithm/min.h> 15*5f757f3fSDimitry Andric #include <__bit/invert_if.h> 16*5f757f3fSDimitry Andric #include <__bit/popcount.h> 17fe6060f1SDimitry Andric #include <__config> 18*5f757f3fSDimitry Andric #include <__functional/identity.h> 19*5f757f3fSDimitry Andric #include <__functional/invoke.h> 20*5f757f3fSDimitry Andric #include <__fwd/bit_reference.h> 21fe6060f1SDimitry Andric #include <__iterator/iterator_traits.h> 22fe6060f1SDimitry Andric 23fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 24fe6060f1SDimitry Andric # pragma GCC system_header 25fe6060f1SDimitry Andric #endif 26fe6060f1SDimitry Andric 27*5f757f3fSDimitry Andric _LIBCPP_PUSH_MACROS 28*5f757f3fSDimitry Andric #include <__undef_macros> 29*5f757f3fSDimitry Andric 30fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 31fe6060f1SDimitry Andric 32*5f757f3fSDimitry Andric // generic implementation 33*5f757f3fSDimitry Andric template <class _AlgPolicy, class _Iter, class _Sent, class _Tp, class _Proj> 34*5f757f3fSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 typename _IterOps<_AlgPolicy>::template __difference_type<_Iter> 35*5f757f3fSDimitry Andric __count(_Iter __first, _Sent __last, const _Tp& __value, _Proj& __proj) { 36*5f757f3fSDimitry Andric typename _IterOps<_AlgPolicy>::template __difference_type<_Iter> __r(0); 37fe6060f1SDimitry Andric for (; __first != __last; ++__first) 38*5f757f3fSDimitry Andric if (std::__invoke(__proj, *__first) == __value) 39fe6060f1SDimitry Andric ++__r; 40fe6060f1SDimitry Andric return __r; 41fe6060f1SDimitry Andric } 42fe6060f1SDimitry Andric 43*5f757f3fSDimitry Andric // __bit_iterator implementation 44*5f757f3fSDimitry Andric template <bool _ToCount, class _Cp, bool _IsConst> 45*5f757f3fSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 typename __bit_iterator<_Cp, _IsConst>::difference_type 46*5f757f3fSDimitry Andric __count_bool(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n) { 47*5f757f3fSDimitry Andric using _It = __bit_iterator<_Cp, _IsConst>; 48*5f757f3fSDimitry Andric using __storage_type = typename _It::__storage_type; 49*5f757f3fSDimitry Andric using difference_type = typename _It::difference_type; 50*5f757f3fSDimitry Andric 51*5f757f3fSDimitry Andric const int __bits_per_word = _It::__bits_per_word; 52*5f757f3fSDimitry Andric difference_type __r = 0; 53*5f757f3fSDimitry Andric // do first partial word 54*5f757f3fSDimitry Andric if (__first.__ctz_ != 0) { 55*5f757f3fSDimitry Andric __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_); 56*5f757f3fSDimitry Andric __storage_type __dn = std::min(__clz_f, __n); 57*5f757f3fSDimitry Andric __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn)); 58*5f757f3fSDimitry Andric __r = std::__libcpp_popcount(std::__invert_if<!_ToCount>(*__first.__seg_) & __m); 59*5f757f3fSDimitry Andric __n -= __dn; 60*5f757f3fSDimitry Andric ++__first.__seg_; 61*5f757f3fSDimitry Andric } 62*5f757f3fSDimitry Andric // do middle whole words 63*5f757f3fSDimitry Andric for (; __n >= __bits_per_word; ++__first.__seg_, __n -= __bits_per_word) 64*5f757f3fSDimitry Andric __r += std::__libcpp_popcount(std::__invert_if<!_ToCount>(*__first.__seg_)); 65*5f757f3fSDimitry Andric // do last partial word 66*5f757f3fSDimitry Andric if (__n > 0) { 67*5f757f3fSDimitry Andric __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n); 68*5f757f3fSDimitry Andric __r += std::__libcpp_popcount(std::__invert_if<!_ToCount>(*__first.__seg_) & __m); 69*5f757f3fSDimitry Andric } 70*5f757f3fSDimitry Andric return __r; 71*5f757f3fSDimitry Andric } 72*5f757f3fSDimitry Andric 73*5f757f3fSDimitry Andric template <class, class _Cp, bool _IsConst, class _Tp, class _Proj, __enable_if_t<__is_identity<_Proj>::value, int> = 0> 74*5f757f3fSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __iter_diff_t<__bit_iterator<_Cp, _IsConst> > 75*5f757f3fSDimitry Andric __count(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, const _Tp& __value, _Proj&) { 76*5f757f3fSDimitry Andric if (__value) 77*5f757f3fSDimitry Andric return std::__count_bool<true>(__first, static_cast<typename _Cp::size_type>(__last - __first)); 78*5f757f3fSDimitry Andric return std::__count_bool<false>(__first, static_cast<typename _Cp::size_type>(__last - __first)); 79*5f757f3fSDimitry Andric } 80*5f757f3fSDimitry Andric 81*5f757f3fSDimitry Andric template <class _InputIterator, class _Tp> 82*5f757f3fSDimitry Andric _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __iter_diff_t<_InputIterator> 83*5f757f3fSDimitry Andric count(_InputIterator __first, _InputIterator __last, const _Tp& __value) { 84*5f757f3fSDimitry Andric __identity __proj; 85*5f757f3fSDimitry Andric return std::__count<_ClassicAlgPolicy>(__first, __last, __value, __proj); 86*5f757f3fSDimitry Andric } 87*5f757f3fSDimitry Andric 88fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD 89fe6060f1SDimitry Andric 90*5f757f3fSDimitry Andric _LIBCPP_POP_MACROS 91*5f757f3fSDimitry Andric 92fe6060f1SDimitry Andric #endif // _LIBCPP___ALGORITHM_COUNT_H 93