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https://github.com/jart/cosmopolitan.git
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181 lines
7 KiB
C++
181 lines
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_FIND_H
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#define _LIBCPP___ALGORITHM_FIND_H
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#include <__algorithm/find_segment_if.h>
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#include <__algorithm/min.h>
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#include <__algorithm/unwrap_iter.h>
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#include <__bit/countr.h>
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#include <__bit/invert_if.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/segmented_iterator.h>
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#include <__string/constexpr_c_functions.h>
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#include <__type_traits/is_integral.h>
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#include <__type_traits/is_same.h>
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#include <__type_traits/is_signed.h>
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#include <__utility/move.h>
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#include <limits>
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#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
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# include <cwchar>
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#endif
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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 _Iter, class _Sent, class _Tp, class _Proj>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iter
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__find(_Iter __first, _Sent __last, const _Tp& __value, _Proj& __proj) {
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for (; __first != __last; ++__first)
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if (std::__invoke(__proj, *__first) == __value)
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break;
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return __first;
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}
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// trivially equality comparable implementations
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template <class _Tp,
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class _Up,
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class _Proj,
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__enable_if_t<__is_identity<_Proj>::value && __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value &&
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sizeof(_Tp) == 1,
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int> = 0>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp* __find(_Tp* __first, _Tp* __last, const _Up& __value, _Proj&) {
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if (auto __ret = std::__constexpr_memchr(__first, __value, __last - __first))
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return __ret;
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return __last;
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}
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#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
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template <class _Tp,
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class _Up,
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class _Proj,
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__enable_if_t<__is_identity<_Proj>::value && __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value &&
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sizeof(_Tp) == sizeof(wchar_t) && _LIBCPP_ALIGNOF(_Tp) >= _LIBCPP_ALIGNOF(wchar_t),
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int> = 0>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp* __find(_Tp* __first, _Tp* __last, const _Up& __value, _Proj&) {
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if (auto __ret = std::__constexpr_wmemchr(__first, __value, __last - __first))
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return __ret;
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return __last;
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}
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#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
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// TODO: This should also be possible to get right with different signedness
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// cast integral types to allow vectorization
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template <class _Tp,
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class _Up,
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class _Proj,
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__enable_if_t<__is_identity<_Proj>::value && !__libcpp_is_trivially_equality_comparable<_Tp, _Up>::value &&
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is_integral<_Tp>::value && is_integral<_Up>::value &&
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is_signed<_Tp>::value == is_signed<_Up>::value,
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int> = 0>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp*
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__find(_Tp* __first, _Tp* __last, const _Up& __value, _Proj& __proj) {
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if (__value < numeric_limits<_Tp>::min() || __value > numeric_limits<_Tp>::max())
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return __last;
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return std::__find(__first, __last, _Tp(__value), __proj);
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}
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// __bit_iterator implementation
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template <bool _ToFind, class _Cp, bool _IsConst>
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_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI __bit_iterator<_Cp, _IsConst>
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__find_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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const int __bits_per_word = _It::__bits_per_word;
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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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__storage_type __b = std::__invert_if<!_ToFind>(*__first.__seg_) & __m;
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if (__b)
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return _It(__first.__seg_, static_cast<unsigned>(std::__libcpp_ctz(__b)));
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if (__n == __dn)
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return __first + __n;
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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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__storage_type __b = std::__invert_if<!_ToFind>(*__first.__seg_);
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if (__b)
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return _It(__first.__seg_, static_cast<unsigned>(std::__libcpp_ctz(__b)));
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}
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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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__storage_type __b = std::__invert_if<!_ToFind>(*__first.__seg_) & __m;
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if (__b)
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return _It(__first.__seg_, static_cast<unsigned>(std::__libcpp_ctz(__b)));
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}
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return _It(__first.__seg_, static_cast<unsigned>(__n));
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}
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template <class _Cp, bool _IsConst, class _Tp, class _Proj, __enable_if_t<__is_identity<_Proj>::value, int> = 0>
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inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __bit_iterator<_Cp, _IsConst>
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__find(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, const _Tp& __value, _Proj&) {
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if (static_cast<bool>(__value))
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return std::__find_bool<true>(__first, static_cast<typename _Cp::size_type>(__last - __first));
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return std::__find_bool<false>(__first, static_cast<typename _Cp::size_type>(__last - __first));
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}
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// segmented iterator implementation
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template <class>
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struct __find_segment;
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template <class _SegmentedIterator,
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class _Tp,
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class _Proj,
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__enable_if_t<__is_segmented_iterator<_SegmentedIterator>::value, int> = 0>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _SegmentedIterator
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__find(_SegmentedIterator __first, _SegmentedIterator __last, const _Tp& __value, _Proj& __proj) {
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return std::__find_segment_if(std::move(__first), std::move(__last), __find_segment<_Tp>(__value), __proj);
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}
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template <class _Tp>
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struct __find_segment {
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const _Tp& __value_;
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR __find_segment(const _Tp& __value) : __value_(__value) {}
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template <class _InputIterator, class _Proj>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _InputIterator
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operator()(_InputIterator __first, _InputIterator __last, _Proj& __proj) const {
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return std::__find(__first, __last, __value_, __proj);
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}
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};
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// public API
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template <class _InputIterator, class _Tp>
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_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
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find(_InputIterator __first, _InputIterator __last, const _Tp& __value) {
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__identity __proj;
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return std::__rewrap_iter(
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__first, std::__find(std::__unwrap_iter(__first), std::__unwrap_iter(__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_FIND_H
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