multiset.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 HPL1_STD_MULTISET_H
#define HPL1_STD_MULTISET_H

#include "common/rb_tree.h"

namespace Hpl1 {
namespace Std {

template<class T, class CompFn = Common::Less<T> >
class multiset {
    using TreeT = Common::RBTree<T, T, Common::Identity<T>, CompFn>;

public:
    using iterator = typename TreeT::BasicIterator;
    using const_iterator = typename TreeT::ConstIterator;

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

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

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

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

    void clear() {
        _items.clear();
    }

    bool empty() {
        return _items.size() == 0;
    }

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

    iterator find(const T &item) {
        const auto it = _items.lowerBound(item);
        if (it != _items.end() && CompareEq(*it, item)) {
            return it;
        }
        return _items.end();
    }

    iterator insert(const T &item) {
        return _items.insert(item);
    }

    void erase(iterator item) {
        _items.erase(item);
    }

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

    size_t erase(const T &item) {
        size_t total = 0;
        for (auto it = _items.lowerBound(item); it != end() && CompareEq(*it, item);) {
            _items.erase(it++);
            ++total;
        }
        return total;
    }

    size_t count(const T &item) const {
        size_t total = 0;
        for (auto it = _items.lowerBound(item); it != end() && CompareEq(*it, item); ++it)
            ++total;
        return total;
    }

private:
    static bool CompareEq(const T &a, const T &b) {
        return !CompFn()(a, b) && !CompFn()(b, a);
    }

    TreeT _items;
};

} // namespace Std

} // namespace Hpl1

#endif