/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

// vim:cindent:ts=8:et:sw=4:

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* a set of ranges on a number-line */

#ifndef nsIntervalSet_h___

#define nsIntervalSet_h___

#include "nsCoord.h"

class nsIPresShell;

/*

 * A list-based class (hopefully tree-based when I get around to it)

 * for representing a set of ranges on a number-line.

 */

class nsIntervalSet {

public:

    typedef nscoord coord_type;

    explicit nsIntervalSet(nsIPresShell* aPresShell);

    ~nsIntervalSet();

    /*

     * Include the interval [aBegin, aEnd] in the set.

     *

     * Removal of intervals added is not supported because that would

     * require keeping track of the individual intervals that were

     * added (nsIntervalMap should do that).  It would be simple to

     * implement ExcludeInterval if anyone wants it, though.

     */

    void IncludeInterval(coord_type aBegin, coord_type aEnd);

    /*

     * Are _some_ points in [aBegin, aEnd] contained within the set

     * of intervals?

     */

    bool Intersects(coord_type aBegin, coord_type aEnd) const;

    /*

     * Are _all_ points in [aBegin, aEnd] contained within the set

     * of intervals?

     */

    bool Contains(coord_type aBegin, coord_type aEnd) const;

    bool IsEmpty() const

    {

        return !mList;

    }

private:

    class Interval {

    public:

        Interval(coord_type aBegin, coord_type aEnd)

            : mBegin(aBegin),

              mEnd(aEnd),

              mPrev(nullptr),

              mNext(nullptr)

        {

        }

        coord_type mBegin;

        coord_type mEnd;

        Interval *mPrev;

        Interval *mNext;

    };

    void* AllocateInterval();

    void FreeInterval(Interval *aInterval);

    Interval           *mList;

    nsIPresShell       *mPresShell;

};

#endif // !defined(nsIntervalSet_h___)