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construct/include/ircd/util/instance_multimap.h
2018-09-01 21:04:34 -07:00

119 lines
2.8 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_UTIL_INSTANCE_MULTIMAP_H
namespace ircd::util
{
template<class K, class T> struct instance_multimap;
}
/// See instance_multimap for purpose and overview.
template<class K,
class T>
struct ircd::util::instance_multimap
{
static std::multimap<K, T *> map;
protected:
typename decltype(map)::iterator it;
instance_multimap(const typename decltype(map)::const_iterator &hint, K&& key);
instance_multimap(K&& key);
instance_multimap(instance_multimap &&) noexcept;
instance_multimap(const instance_multimap &);
instance_multimap &operator=(instance_multimap &&) noexcept;
instance_multimap &operator=(const instance_multimap &);
~instance_multimap() noexcept;
};
template<class K,
class T>
ircd::util::instance_multimap<K, T>::instance_multimap(K&& key)
:it
{
map.emplace(std::forward<K>(key), static_cast<T *>(this))
}
{}
template<class K,
class T>
ircd::util::instance_multimap<K, T>::instance_multimap(const typename decltype(map)::const_iterator &hint,
K&& key)
:it
{
map.emplace_hint(hint, std::forward<K>(key), static_cast<T *>(this))
}
{}
template<class K,
class T>
ircd::util::instance_multimap<K, T>::instance_multimap(instance_multimap &&other)
noexcept
:it
{
std::move(other.it)
}
{
if(it != end(map))
{
it->second = static_cast<T *>(this);
other.it = end(map);
}
}
template<class K,
class T>
ircd::util::instance_multimap<K, T>::instance_multimap(const instance_multimap &other)
:it
{
other.it != end(map)?
map.emplace_hint(other.it, other.it->first, static_cast<T *>(this)):
end(map)
}
{}
template<class K,
class T>
ircd::util::instance_multimap<K, T> &
ircd::util::instance_multimap<K, T>::operator=(instance_multimap &&other)
noexcept
{
this->~instance_multimap();
it = std::move(other.it);
if(it != end(map))
it->second = static_cast<T *>(this);
other.it = end(map);
return *this;
}
template<class K,
class T>
ircd::util::instance_multimap<K, T> &
ircd::util::instance_multimap<K, T>::operator=(const instance_multimap &other)
{
this->~instance_multimap();
it = other.it != end(map)?
map.emplace_hint(other.it, other.it->first, static_cast<T *>(this)):
end(map);
return *this;
}
template<class K,
class T>
ircd::util::instance_multimap<K, T>::~instance_multimap()
noexcept
{
if(it != end(map))
map.erase(it);
}