mirror of
https://github.com/matrix-construct/construct
synced 2024-11-26 16:52:44 +01:00
77 lines
1.9 KiB
C++
77 lines
1.9 KiB
C++
// Matrix Construct
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//
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// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#pragma once
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#define HAVE_IRCD_UTIL_UNIQUE_ITERATOR_H
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namespace ircd::util
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{
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template<class container,
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class iterator = typename container::iterator>
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struct unique_iterator;
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template<class container>
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struct unique_const_iterator;
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}
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//
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// For objects using the pattern of adding their own instance to a container
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// in their constructor, storing an iterator as a member, and then removing
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// themselves using the iterator in their destructor. It is unsafe to do that.
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// Use this instead; or better, use ircd::instance_list<>
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//
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template<class container,
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class iterator>
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struct ircd::util::unique_iterator
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{
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container *c;
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iterator it;
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unique_iterator(container &c, iterator it)
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:c{&c}
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,it{std::move(it)}
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{}
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unique_iterator()
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:c{nullptr}
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{}
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unique_iterator(const unique_iterator &) = delete;
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unique_iterator(unique_iterator &&o) noexcept
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:c{std::move(o.c)}
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,it{std::move(o.it)}
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{
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o.c = nullptr;
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}
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unique_iterator &operator=(const unique_iterator &) = delete;
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unique_iterator &operator=(unique_iterator &&o) noexcept
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{
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this->~unique_iterator();
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c = std::move(o.c);
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it = std::move(o.it);
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o.c = nullptr;
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return *this;
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}
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~unique_iterator() noexcept
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{
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if(c)
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c->erase(it);
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}
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};
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template<class container>
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struct ircd::util::unique_const_iterator
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:unique_iterator<container, typename container::const_iterator>
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{
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using iterator_type = typename container::const_iterator;
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using unique_iterator<container, iterator_type>::unique_iterator;
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};
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