5aaefa510e
libc++ has started splicing standard library headers into much more fine-grained content for maintainability. It's very likely that outdated and naive tooling (some of which is outside of LLVM's scope) will suggest users include things such as <__ranges/access.h> instead of <ranges>, and Hyrum's law suggests that users will eventually begin to rely on this without the help of tooling. As such, this commit intends to protect users from themselves, by making it a hard error for anyone outside of the standard library to include libc++ detail headers. Differential Revision: https://reviews.llvm.org/D106124
114 lines
4.7 KiB
C++
114 lines
4.7 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_SEARCH_N_H
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#define _LIBCPP___ALGORITHM_SEARCH_N_H
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#include <__algorithm/comp.h>
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#include <__config>
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#include <__iterator/iterator_traits.h>
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#include <type_traits> // __convert_to_integral
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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# pragma clang include_instead(<algorithm>)
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <class _BinaryPredicate, class _ForwardIterator, class _Size, class _Tp>
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_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator __search_n(_ForwardIterator __first, _ForwardIterator __last,
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_Size __count, const _Tp& __value_, _BinaryPredicate __pred,
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forward_iterator_tag) {
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if (__count <= 0)
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return __first;
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while (true) {
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// Find first element in sequence that matchs __value_, with a mininum of loop checks
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while (true) {
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if (__first == __last) // return __last if no element matches __value_
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return __last;
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if (__pred(*__first, __value_))
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break;
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++__first;
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}
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// *__first matches __value_, now match elements after here
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_ForwardIterator __m = __first;
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_Size __c(0);
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while (true) {
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if (++__c == __count) // If pattern exhausted, __first is the answer (works for 1 element pattern)
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return __first;
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if (++__m == __last) // Otherwise if source exhaused, pattern not found
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return __last;
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if (!__pred(*__m, __value_)) // if there is a mismatch, restart with a new __first
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{
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__first = __m;
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++__first;
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break;
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} // else there is a match, check next elements
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}
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}
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}
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template <class _BinaryPredicate, class _RandomAccessIterator, class _Size, class _Tp>
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_LIBCPP_CONSTEXPR_AFTER_CXX17 _RandomAccessIterator __search_n(_RandomAccessIterator __first,
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_RandomAccessIterator __last, _Size __count,
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const _Tp& __value_, _BinaryPredicate __pred,
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random_access_iterator_tag) {
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typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
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if (__count <= 0)
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return __first;
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_Size __len = static_cast<_Size>(__last - __first);
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if (__len < __count)
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return __last;
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const _RandomAccessIterator __s = __last - difference_type(__count - 1); // Start of pattern match can't go beyond here
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while (true) {
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// Find first element in sequence that matchs __value_, with a mininum of loop checks
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while (true) {
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if (__first >= __s) // return __last if no element matches __value_
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return __last;
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if (__pred(*__first, __value_))
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break;
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++__first;
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}
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// *__first matches __value_, now match elements after here
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_RandomAccessIterator __m = __first;
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_Size __c(0);
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while (true) {
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if (++__c == __count) // If pattern exhausted, __first is the answer (works for 1 element pattern)
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return __first;
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++__m; // no need to check range on __m because __s guarantees we have enough source
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if (!__pred(*__m, __value_)) // if there is a mismatch, restart with a new __first
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{
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__first = __m;
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++__first;
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break;
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} // else there is a match, check next elements
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}
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}
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}
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template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
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_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator search_n(
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_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value_, _BinaryPredicate __pred) {
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return _VSTD::__search_n<_BinaryPredicate&>(
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__first, __last, _VSTD::__convert_to_integral(__count), __value_, __pred,
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typename iterator_traits<_ForwardIterator>::iterator_category());
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}
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template <class _ForwardIterator, class _Size, class _Tp>
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_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
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search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value_) {
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typedef typename iterator_traits<_ForwardIterator>::value_type __v;
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return _VSTD::search_n(__first, __last, _VSTD::__convert_to_integral(__count), __value_, __equal_to<__v, _Tp>());
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}
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___ALGORITHM_SEARCH_N_H
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