stablemap.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program 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, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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/>.
 *
 */

#ifndef COMMON_STABLEMAP_H
#define COMMON_STABLEMAP_H

#include "common/rb_tree.h"

namespace Common {

template<class Key, class Val, class CompFunc = Common::Less<Key> >
class StableMap {
    using TreeT = RBTree<Pair<Key, Val>, Key, PairFirst<Key, Val>, CompFunc>;

public:
    using value_type = Pair<Key, Val>;                    
    using iterator = typename TreeT::BasicIterator;       
    using const_iterator = typename TreeT::ConstIterator; 
    void clear() {
        _items.clear();
    }

    iterator begin() {
        return _items.begin();
    }

    iterator end() {
        return _items.end();
    }

    const_iterator begin() const {
        return _items.begin();
    }

    const_iterator end() const {
        return _items.end();
    }

    const_iterator lower_bound(const Key &key) const {
        return _items.lowerBound(key);
    }

    iterator lower_bound(const Key &key) {
        return _items.lowerBound(key);
    }

    iterator upper_bound(const Key &key) {
        return _items.upperBound(key);
    }

    iterator find(const Key &theKey) {
        iterator it = _items.lowerBound(theKey);
        if (it != this->end() && compareEqual(it->first, theKey))
            return it;
        return this->end();
    }

    const_iterator find(const Key &theKey) const {
        const_iterator it = _items.lowerBound(theKey);
        if (it != this->end() && compareEqual(it->first, theKey))
            return it;
        return this->end();
    }

    Val &operator[](const Key &theKey) {
        iterator it = _items.lowerBound(theKey);
        if (it == this->end() || !compareEqual(it->first, theKey)) {
            iterator i = _items.insert(value_type(theKey, Val()));
            return i->second;
        }
        return it->second;
    }

    iterator erase(iterator it) {
        return _items.erase(it);
    }

    iterator erase(iterator first, iterator last) {
        return _items.erase(first, last);
    }

    size_t erase(const Key &theKey) {
        iterator it = find(theKey);
        if (it != this->end()) {
            erase(it);
            return 1;
        }
        return 0;
    }

    Pair<iterator, bool> insert(const value_type &val) {
        iterator it = _items.lowerBound(val.first);
        if (it == this->end() || !compareEqual(it->first, val.first))
            return {_items.insert(val), true};
        return {it, false};
    }

    size_t size() const {
        return _items.size();
    }

    bool empty() const {
        return _items.isEmpty();
    }

    size_t count(const Key &key) {
        int count_ = 0;
        for (iterator it = this->begin(); it != this->end(); ++it) {
            if (compareEqual(it->first, key))
                ++count_;
        }
        return count_;
    }

private:
    bool compareEqual(const Key &a, const Key &b) const {
        return !_comp(a, b) && !_comp(b, a);
    }

    TreeT _items;
    CompFunc _comp;
};

} // End of namespace Common

#endif