set.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 AGS_STD_SET_H
#define AGS_STD_SET_H

#include "common/array.h"

namespace AGS3 {
namespace std {

template<class T, class Comparitor = Common::Less<T> >
class set : public Common::SortedArray<T, const T &> {
private:
    static int ComparatorFn(const T &a, const T &b) {
        return Comparitor().operator()(a, b) ? -1 : 0;
    }

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

public:
    struct Entry {
        const T &_value;
        Entry(const T &item) : _value(item) {
        }
    };
public:
    using iterator = typename Common::SortedArray<T, const T &>::iterator;
    using const_iterator = typename Common::SortedArray<T, const T &>::const_iterator;

    set() : Common::SortedArray<T, const T & >(ComparatorFn) {}

    iterator find(const T &item) {
        iterator begin = this->begin();
        iterator end = this->end();
        while (begin < end) {
            iterator mid = begin + (Common::distance(begin, end) / 2);
            if (ComparatorFn(item, *mid))
                end = mid;
            else if (ComparatorFn(*mid, item))
                begin = mid + 1;
            else
                return mid;
        }
        return this->end();
    }

    Entry insert(const T &item) {
        Common::SortedArray<T, const T &>::insert(item);
        return Entry(item);
    }

    void erase(iterator item) {
        Common::SortedArray<T, const T &>::erase(item);
    }

    void erase(iterator first, iterator last) {
        Common::SortedArray<T, const T &>::erase(first, last);
    }

    size_t erase(const T &item) {
        iterator first = find(item);
        if (first == this->end())
            return 0;
        iterator end = first + 1;
        while (end != this->end() && CompareEq(*first, *end)) {
            ++end;
        }
        size_t erased = Common::distance(first, end);
        this->erase(first, end);
        return erased;
    }

    size_t count(const T item) const {
        size_t total = 0;
        for (const_iterator it = this->begin(); it != this->end(); ++it) {
            if (CompareEq(*it, item))
                ++total;
            else if (!ComparatorFn(item, *it))
                // Passed beyond possibility of matches
                break;
        }

        return total;
    }
};

} // namespace std
} // namespace AGS3

#endif