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d10dc5a06f
We originally put implementation-detail function objects into individual namespaces for `std::ranges` without a good reason for doing so. This practice was continued, presumably because there was prior art. Since there's no reason to keep these namespaces, this commit removes them, which will slightly impact binary size. This commit does not apply to CPOs, some of which need additional work.
96 lines
3.0 KiB
C++
96 lines
3.0 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___ITERATOR_DISTANCE_H
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#define _LIBCPP___ITERATOR_DISTANCE_H
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#include <__config>
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#include <__iterator/concepts.h>
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#include <__iterator/incrementable_traits.h>
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#include <__iterator/iterator_traits.h>
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#include <__ranges/access.h>
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#include <__ranges/concepts.h>
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#include <__ranges/size.h>
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#include <__type_traits/decay.h>
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#include <__type_traits/remove_cvref.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_BEGIN_NAMESPACE_STD
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template <class _InputIter>
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inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 typename iterator_traits<_InputIter>::difference_type
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__distance(_InputIter __first, _InputIter __last, input_iterator_tag) {
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typename iterator_traits<_InputIter>::difference_type __r(0);
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for (; __first != __last; ++__first)
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++__r;
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return __r;
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}
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template <class _RandIter>
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inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 typename iterator_traits<_RandIter>::difference_type
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__distance(_RandIter __first, _RandIter __last, random_access_iterator_tag) {
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return __last - __first;
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}
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template <class _InputIter>
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inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 typename iterator_traits<_InputIter>::difference_type
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distance(_InputIter __first, _InputIter __last) {
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return std::__distance(__first, __last, typename iterator_traits<_InputIter>::iterator_category());
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}
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#if _LIBCPP_STD_VER >= 20
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// [range.iter.op.distance]
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namespace ranges {
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struct __distance {
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template <class _Ip, sentinel_for<_Ip> _Sp>
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requires(!sized_sentinel_for<_Sp, _Ip>)
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_LIBCPP_HIDE_FROM_ABI constexpr iter_difference_t<_Ip> operator()(_Ip __first, _Sp __last) const {
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iter_difference_t<_Ip> __n = 0;
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while (__first != __last) {
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++__first;
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++__n;
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}
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return __n;
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}
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template <class _Ip, sized_sentinel_for<decay_t<_Ip>> _Sp>
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_LIBCPP_HIDE_FROM_ABI constexpr iter_difference_t<_Ip> operator()(_Ip&& __first, _Sp __last) const {
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if constexpr (sized_sentinel_for<_Sp, __remove_cvref_t<_Ip>>) {
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return __last - __first;
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} else {
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return __last - decay_t<_Ip>(__first);
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}
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}
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template <range _Rp>
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_LIBCPP_HIDE_FROM_ABI constexpr range_difference_t<_Rp> operator()(_Rp&& __r) const {
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if constexpr (sized_range<_Rp>) {
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return static_cast<range_difference_t<_Rp>>(ranges::size(__r));
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} else {
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return operator()(ranges::begin(__r), ranges::end(__r));
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}
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}
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};
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inline namespace __cpo {
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inline constexpr auto distance = __distance{};
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} // namespace __cpo
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} // namespace ranges
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#endif // _LIBCPP_STD_VER >= 20
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___ITERATOR_DISTANCE_H
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