4c19854222
In preparation for running clang-format on the whole code base, we are also removing mentions of the legacy _LIBCPP_INLINE_VISIBILITY macro in favor of the newer _LIBCPP_HIDE_FROM_ABI. We're still leaving the definition of _LIBCPP_INLINE_VISIBILITY to avoid creating needless breakage in case some older patches are checked-in with mentions of the old macro. After we branch for LLVM 18, we can do another pass to clean up remaining uses of the macro that might have gotten introduced by mistake (if any) and remove the macro itself at the same time. This is just a minor convenience to smooth out the transition as much as possible. See https://discourse.llvm.org/t/rfc-clang-formatting-all-of-libc-once-and-for-all for the clang-format proposal.
113 lines
4.3 KiB
C++
113 lines
4.3 KiB
C++
//===----------------------------------------------------------------------===//
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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_SAMPLE_H
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#define _LIBCPP___ALGORITHM_SAMPLE_H
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#include <__algorithm/iterator_operations.h>
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#include <__algorithm/min.h>
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#include <__assert>
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#include <__config>
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#include <__iterator/distance.h>
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#include <__iterator/iterator_traits.h>
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#include <__random/uniform_int_distribution.h>
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#include <__type_traits/common_type.h>
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#include <__utility/move.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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template <class _AlgPolicy,
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class _PopulationIterator, class _PopulationSentinel, class _SampleIterator, class _Distance,
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class _UniformRandomNumberGenerator>
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_LIBCPP_HIDE_FROM_ABI
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_SampleIterator __sample(_PopulationIterator __first,
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_PopulationSentinel __last, _SampleIterator __output_iter,
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_Distance __n,
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_UniformRandomNumberGenerator& __g,
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input_iterator_tag) {
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_Distance __k = 0;
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for (; __first != __last && __k < __n; ++__first, (void) ++__k)
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__output_iter[__k] = *__first;
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_Distance __sz = __k;
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for (; __first != __last; ++__first, (void) ++__k) {
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_Distance __r = uniform_int_distribution<_Distance>(0, __k)(__g);
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if (__r < __sz)
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__output_iter[__r] = *__first;
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}
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return __output_iter + _VSTD::min(__n, __k);
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}
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template <class _AlgPolicy,
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class _PopulationIterator, class _PopulationSentinel, class _SampleIterator, class _Distance,
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class _UniformRandomNumberGenerator>
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_LIBCPP_HIDE_FROM_ABI
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_SampleIterator __sample(_PopulationIterator __first,
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_PopulationSentinel __last, _SampleIterator __output_iter,
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_Distance __n,
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_UniformRandomNumberGenerator& __g,
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forward_iterator_tag) {
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_Distance __unsampled_sz = _IterOps<_AlgPolicy>::distance(__first, __last);
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for (__n = _VSTD::min(__n, __unsampled_sz); __n != 0; ++__first) {
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_Distance __r = uniform_int_distribution<_Distance>(0, --__unsampled_sz)(__g);
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if (__r < __n) {
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*__output_iter++ = *__first;
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--__n;
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}
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}
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return __output_iter;
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}
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template <class _AlgPolicy,
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class _PopulationIterator, class _PopulationSentinel, class _SampleIterator, class _Distance,
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class _UniformRandomNumberGenerator>
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_LIBCPP_HIDE_FROM_ABI
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_SampleIterator __sample(_PopulationIterator __first,
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_PopulationSentinel __last, _SampleIterator __output_iter,
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_Distance __n, _UniformRandomNumberGenerator& __g) {
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_LIBCPP_ASSERT_UNCATEGORIZED(__n >= 0, "N must be a positive number.");
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using _PopIterCategory = typename _IterOps<_AlgPolicy>::template __iterator_category<_PopulationIterator>;
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using _Difference = typename _IterOps<_AlgPolicy>::template __difference_type<_PopulationIterator>;
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using _CommonType = typename common_type<_Distance, _Difference>::type;
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return std::__sample<_AlgPolicy>(
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std::move(__first), std::move(__last), std::move(__output_iter), _CommonType(__n),
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__g, _PopIterCategory());
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}
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#if _LIBCPP_STD_VER >= 17
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template <class _PopulationIterator, class _SampleIterator, class _Distance,
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class _UniformRandomNumberGenerator>
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inline _LIBCPP_HIDE_FROM_ABI
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_SampleIterator sample(_PopulationIterator __first,
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_PopulationIterator __last, _SampleIterator __output_iter,
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_Distance __n, _UniformRandomNumberGenerator&& __g) {
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static_assert(__has_forward_iterator_category<_PopulationIterator>::value ||
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__has_random_access_iterator_category<_SampleIterator>::value,
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"SampleIterator must meet the requirements of RandomAccessIterator");
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return std::__sample<_ClassicAlgPolicy>(
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std::move(__first), std::move(__last), std::move(__output_iter), __n, __g);
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}
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#endif // _LIBCPP_STD_VER >= 17
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___ALGORITHM_SAMPLE_H
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