f1417eb9b1
Most of our private headers need to be treated as submodules so that Clang modules can export things correctly. Previous commits that split monolithic headers into smaller chunks were unaware of this requirement, and so this is being addressed in one fell swoop. Moving forward, most new headers will need to have their own submodule (anything that's conditionally included is exempt from this rule, which means `__support` headers aren't made into submodules). This hasn't been marked NFC, since I'm not 100% sure that's the case. Differential Revision: https://reviews.llvm.org/D103551
75 lines
2.1 KiB
C++
75 lines
2.1 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_PREV_H
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#define _LIBCPP___ITERATOR_PREV_H
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#include <__config>
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#include <__function_like.h>
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#include <__iterator/advance.h>
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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 <type_traits>
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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 _InputIter>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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typename enable_if<__is_cpp17_input_iterator<_InputIter>::value, _InputIter>::type
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prev(_InputIter __x, typename iterator_traits<_InputIter>::difference_type __n = 1) {
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_LIBCPP_ASSERT(__n <= 0 || __is_cpp17_bidirectional_iterator<_InputIter>::value,
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"Attempt to prev(it, n) with a positive n on a non-bidirectional iterator");
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_VSTD::advance(__x, -__n);
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return __x;
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}
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#if !defined(_LIBCPP_HAS_NO_RANGES)
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namespace ranges {
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struct __prev_fn final : private __function_like {
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constexpr explicit __prev_fn(__tag __x) noexcept : __function_like(__x) {}
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template <bidirectional_iterator _Ip>
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constexpr _Ip operator()(_Ip __x) const {
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--__x;
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return __x;
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}
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template <bidirectional_iterator _Ip>
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constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n) const {
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ranges::advance(__x, -__n);
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return __x;
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}
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template <bidirectional_iterator _Ip>
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constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n, _Ip __bound) const {
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ranges::advance(__x, -__n, __bound);
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return __x;
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}
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};
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inline constexpr auto prev = __prev_fn(__function_like::__tag());
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} // namespace ranges
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#endif // !defined(_LIBCPP_HAS_NO_RANGES)
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___ITERATOR_PREV_H
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