inspircd/include/flat_map.h

/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2019-2021, 2024 Sadie Powell <sadie@witchery.services>
 *   Copyright (C) 2014 Attila Molnar <attilamolnar@hush.com>
 *
 * This file is part of InspIRCd.  InspIRCd is free software: you can
 * redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation, version 2.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#pragma once

namespace insp
{

namespace detail
{

template <typename T, typename Comp>
class map_pair_compare final
	: public Comp
{
	typedef T value_type;
	typedef typename value_type::first_type key_type;

public:
	bool operator()(const value_type& x, const value_type& y) const
	{
		return Comp::operator()(x.first, y.first);
	}

	bool operator()(const value_type& x, const key_type& y) const
	{
		return Comp::operator()(x.first, y);
	}

	bool operator()(const key_type& x, const value_type& y) const
	{
		return Comp::operator()(x, y.first);
	}
};

template <typename Val, typename Comp>
class map_value_compare
{
public:
	bool operator()(const Val& x, const Val& y) const
	{
		Comp c;
		return c(x.first, y.first);
	}
};

template <typename T, typename Comp, typename Key = T, typename ElementComp = Comp>
class flat_map_base
{
protected:
	typedef std::vector<T> storage_type;
	storage_type vect;

public:
	typedef typename storage_type::iterator iterator;
	typedef typename storage_type::const_iterator const_iterator;
	typedef typename storage_type::reverse_iterator reverse_iterator;
	typedef typename storage_type::const_reverse_iterator const_reverse_iterator;

	typedef typename storage_type::size_type size_type;
	typedef typename storage_type::difference_type difference_type;
	typedef Key key_type;
	typedef T value_type;

	typedef Comp key_compare;
	typedef ElementComp value_compare;

	flat_map_base() = default;

	flat_map_base(const flat_map_base& other)
		: vect(other.vect)
	{
	}

	flat_map_base& operator=(const flat_map_base& other) = default;

	size_type size() const { return vect.size(); }
	bool empty() const { return vect.empty(); }
	size_type capacity() const { return vect.capacity(); }
	size_type max_size() const { return vect.max_size(); }

	void clear() { vect.clear(); }
	void reserve(size_type n) { vect.reserve(n); }
	void shrink_to_fit() { vect.shrink_to_fit(); }

	iterator begin() { return vect.begin(); }
	iterator end() { return vect.end(); }
	reverse_iterator rbegin() { return vect.rbegin(); }
	reverse_iterator rend() { return vect.rend(); }

	const_iterator begin() const { return vect.begin(); }
	const_iterator end() const { return vect.end(); }
	const_reverse_iterator rbegin() const { return vect.rbegin(); }
	const_reverse_iterator rend() const { return vect.rend(); }

	key_compare key_comp() const { return Comp(); }

	iterator erase(iterator it) { return vect.erase(it); }
	iterator erase(iterator first, iterator last) { return vect.erase(first, last); }
	size_type erase(const key_type& x)
	{
		size_type n = vect.size();
		std::pair<iterator, iterator> itpair = equal_range(x);
		vect.erase(itpair.first, itpair.second);
		return n - vect.size();
	}

	iterator find(const key_type& x)
	{
		value_compare c;
		iterator it = std::lower_bound(vect.begin(), vect.end(), x, c);
		if ((it != vect.end()) && (!c(x, *it)))
			return it;
		return vect.end();
	}

	const_iterator find(const key_type& x) const
	{
		// Same as above but this time we return a const_iterator
		value_compare c;
		const_iterator it = std::lower_bound(vect.begin(), vect.end(), x, c);
		if ((it != vect.end()) && (!c(x, *it)))
			return it;
		return vect.end();
	}

	std::pair<iterator, iterator> equal_range(const key_type& x)
	{
		return std::equal_range(vect.begin(), vect.end(), x, value_compare());
	}

	std::pair<const_iterator, const_iterator> equal_range(const key_type& x) const
	{
		return std::equal_range(vect.begin(), vect.end(), x, value_compare());
	}

	iterator lower_bound(const key_type& x)
	{
		return std::lower_bound(vect.begin(), vect.end(), x, value_compare());
	}

	const_iterator lower_bound(const key_type& x) const
	{
		return std::lower_bound(vect.begin(), vect.end(), x, value_compare());
	}

	iterator upper_bound(const key_type& x)
	{
		return std::upper_bound(vect.begin(), vect.end(), x, value_compare());
	}

	const_iterator upper_bound(const key_type& x) const
	{
		return std::upper_bound(vect.begin(), vect.end(), x, value_compare());
	}

	size_type count(const key_type& x) const
	{
		std::pair<const_iterator, const_iterator> itpair = equal_range(x);
		return std::distance(itpair.first, itpair.second);
	}

protected:
	std::pair<iterator, bool> insert_single(const value_type& x)
	{
		bool inserted = false;

		value_compare c;
		iterator it = std::lower_bound(vect.begin(), vect.end(), x, c);
		if ((it == vect.end()) || (c(x, *it)))
		{
			inserted = true;
			it = vect.insert(it, x);
		}
		return std::make_pair(it, inserted);
	}

	iterator insert_multi(const value_type& x)
	{
		iterator it = std::lower_bound(vect.begin(), vect.end(), x, value_compare());
		return vect.insert(it, x);
	}
};

} // namespace detail

template <typename T, typename Comp = std::less<T>, typename ElementComp = Comp>
class flat_set
	: public detail::flat_map_base<T, Comp, T, ElementComp>
{
	typedef detail::flat_map_base<T, Comp, T, ElementComp> base_type;

public:
	typedef typename base_type::iterator iterator;
	typedef typename base_type::value_type value_type;

	flat_set() = default;

	template <typename InputIterator>
	flat_set(InputIterator first, InputIterator last)
	{
		this->insert(first, last);
	}

	flat_set(std::initializer_list<value_type> init)
	{
		for (const auto& elem : init)
			insert(elem);
	}

	flat_set(const flat_set& other)
		: base_type(other)
	{
	}

	flat_set& operator=(const flat_set& other) = default;

	template <typename... Args>
	std::pair<iterator, bool> emplace(Args&&... args)
	{
		return insert(value_type(std::forward<Args>(args)...));
	}

	std::pair<iterator, bool> insert(const value_type& x)
	{
		return this->insert_single(x);
	}

	template <typename InputIterator>
	void insert(InputIterator first, InputIterator last)
	{
		for (; first != last; ++first)
			this->insert_single(*first);
	}

	void swap(flat_set& other)
	{
		base_type::vect.swap(other.vect);
	}
};

template <typename T, typename Comp = std::less<T>, typename ElementComp = Comp>
class flat_multiset
	: public detail::flat_map_base<T, Comp, T, ElementComp>
{
	typedef detail::flat_map_base<T, Comp, T, ElementComp> base_type;

public:
	typedef typename base_type::iterator iterator;
	typedef typename base_type::value_type value_type;

	flat_multiset() = default;

	template <typename InputIterator>
	flat_multiset(InputIterator first, InputIterator last)
	{
		this->insert(first, last);
	}

	flat_multiset(std::initializer_list<value_type> init)
	{
		for (const auto& elem : init)
			insert(elem);
	}

	flat_multiset(const flat_multiset& other)
		: base_type(other)
	{
	}

	flat_multiset& operator=(const flat_multiset& other) = default;

	template <typename... Args>
	iterator emplace(Args&&... args)
	{
		return insert(value_type(std::forward<Args>(args)...));
	}

	iterator insert(const value_type& x)
	{
		return this->insert_multi(x);
	}

	template <typename InputIterator>
	void insert(InputIterator first, InputIterator last)
	{
		for (; first != last; ++first)
			insert_multi(*first);
	}

	void swap(flat_multiset& other)
	{
		base_type::vect.swap(other.vect);
	}
};

template <typename T, typename U, typename Comp = std::less<T>, typename ElementComp = Comp >
class flat_map
	: public detail::flat_map_base<std::pair<T, U>, Comp, T, detail::map_pair_compare<std::pair<T, U>, ElementComp>>
{
	typedef detail::flat_map_base<std::pair<T, U>, Comp, T, detail::map_pair_compare<std::pair<T, U>, ElementComp>> base_type;

public:
	typedef typename base_type::iterator iterator;
	typedef typename base_type::key_type key_type;
	typedef typename base_type::value_type value_type;
	typedef U mapped_type;
	typedef typename base_type::value_compare value_compare;

	flat_map() = default;

	template <typename InputIterator>
	flat_map(InputIterator first, InputIterator last)
	{
		insert(first, last);
	}

	flat_map(std::initializer_list<value_type> init)
	{
		for (const auto& elem : init)
			insert(elem);
	}

	flat_map(const flat_map& other)
		: base_type(other)
	{
	}

	flat_map& operator=(const flat_map& other) = default;

	template <typename... Args>
	std::pair<iterator, bool> emplace(Args&&... args)
	{
		return insert(value_type(std::forward<Args>(args)...));
	}

	std::pair<iterator, bool> insert(const value_type& x)
	{
		return this->insert_single(x);
	}

	template <typename InputIterator>
	void insert(InputIterator first, InputIterator last)
	{
		for (; first != last; ++first)
			this->insert_single(*first);
	}

	void swap(flat_map& other)
	{
		base_type::vect.swap(other.vect);
	}

	mapped_type& operator[](const key_type& x)
	{
		return insert(value_type(x, mapped_type())).first->second;
	}

	value_compare value_comp() const
	{
		return value_compare();
	}
};

template <typename T, typename U, typename Comp = std::less<T>, typename ElementComp = Comp >
class flat_multimap
	: public detail::flat_map_base<std::pair<T, U>, Comp, T, detail::map_pair_compare<std::pair<T, U>, ElementComp>>
{
	typedef detail::flat_map_base<std::pair<T, U>, Comp, T, detail::map_pair_compare<std::pair<T, U>, ElementComp>> base_type;

public:
	typedef typename base_type::iterator iterator;
	typedef typename base_type::value_type value_type;
	typedef U mapped_type;
	typedef typename base_type::value_compare value_compare;

	flat_multimap() = default;

	template <typename InputIterator>
	flat_multimap(InputIterator first, InputIterator last)
	{
		this->insert(first, last);
	}

	flat_multimap(std::initializer_list<value_type> init)
	{
		for (const auto& elem : init)
			insert(elem);
	}

	flat_multimap(const flat_multimap& other)
		: base_type(other)
	{
	}

	flat_multimap& operator=(const flat_multimap& other) = default;

	template <typename... Args>
	iterator emplace(Args&&... args)
	{
		return insert(value_type(std::forward<Args>(args)...));
	}

	iterator insert(const value_type& x)
	{
		return this->insert_multi(x);
	}

	template <typename InputIterator>
	void insert(InputIterator first, InputIterator last)
	{
		for (; first != last; ++first)
			this->insert_multi(*first);
	}

	void swap(flat_multimap& other)
	{
		base_type::vect.swap(other.vect);
	}

	value_compare value_comp() const
	{
		return value_compare();
	}
};

} // namespace insp