mirror of
https://codeberg.org/ziglang/zig.git
synced 2026-05-02 07:49:22 +03:00
Alex Rønne Petersen
95 lines
3.4 KiB
C++
Vendored
95 lines
3.4 KiB
C++
Vendored
//===----------------------------------------------------------------------===//
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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_COPY_N_H
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#define _LIBCPP___ALGORITHM_COPY_N_H
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#include <__algorithm/copy.h>
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#include <__algorithm/iterator_operations.h>
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#include <__config>
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#include <__iterator/iterator_traits.h>
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#include <__type_traits/enable_if.h>
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#include <__utility/convert_to_integral.h>
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#include <__utility/move.h>
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#include <__utility/pair.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 _InIter,
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class _OutIter,
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__enable_if_t<__has_random_access_iterator_category<_InIter>::value, int> = 0>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InIter, _OutIter>
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__copy_n(_InIter __first, typename _IterOps<_AlgPolicy>::template __difference_type<_InIter> __n, _OutIter __result) {
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return std::__copy(__first, __first + __n, std::move(__result));
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}
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template <class _AlgPolicy,
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class _InIter,
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class _OutIter,
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__enable_if_t<!__has_random_access_iterator_category<_InIter>::value, int> = 0>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InIter, _OutIter>
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__copy_n(_InIter __first, typename _IterOps<_AlgPolicy>::template __difference_type<_InIter> __n, _OutIter __result) {
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while (__n != 0) {
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*__result = *__first;
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++__first;
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++__result;
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--__n;
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}
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return std::make_pair(std::move(__first), std::move(__result));
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}
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// The InputIterator case is handled specially here because it's been written in a way to avoid incrementing __first
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// if not absolutely required. This was done to allow its use with istream_iterator and we want to avoid breaking
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// people, at least currently.
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// See https://github.com/llvm/llvm-project/commit/99847d2bf132854fffa019bab19818768102ccad
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template <class _InputIterator,
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class _Size,
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class _OutputIterator,
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__enable_if_t<__has_exactly_input_iterator_category<_InputIterator>::value, int> = 0>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
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copy_n(_InputIterator __first, _Size __n, _OutputIterator __result) {
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using _IntegralSize = decltype(std::__convert_to_integral(__n));
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_IntegralSize __converted = __n;
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if (__converted > 0) {
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*__result = *__first;
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++__result;
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for (--__converted; __converted > 0; --__converted) {
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++__first;
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*__result = *__first;
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++__result;
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}
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}
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return __result;
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}
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template <class _InputIterator,
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class _Size,
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class _OutputIterator,
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__enable_if_t<!__has_exactly_input_iterator_category<_InputIterator>::value, int> = 0>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
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copy_n(_InputIterator __first, _Size __n, _OutputIterator __result) {
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using _IntegralSize = decltype(std::__convert_to_integral(__n));
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_IntegralSize __converted = __n;
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return std::__copy_n<_ClassicAlgPolicy>(__first, __iterator_difference_type<_InputIterator>(__converted), __result)
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.second;
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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_COPY_N_H
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