mirror of
https://github.com/matrix-construct/construct
synced 2024-06-10 05:58:56 +02:00
87 lines
2.5 KiB
C++
87 lines
2.5 KiB
C++
// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2018 Jason Volk
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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.
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//
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// THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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// DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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// IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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// POSSIBILITY OF SUCH DAMAGE.
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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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