/*

 **********************************************************************

 *   Copyright (C) 1998-2004, International Business Machines

 *   Corporation and others.  All Rights Reserved.

 **********************************************************************

 */

#ifndef __LEINSERTIONLIST_H

#define __LEINSERTIONLIST_H

#include "LETypes.h"

U_NAMESPACE_BEGIN

struct InsertionRecord;

/**

 * This class encapsulates the callback used by <code>LEInsertionList</code>

 * to apply an insertion from the insertion list.

 *

 * @internal

 */

class LEInsertionCallback

{

public:

    /**

     * This method will be called by <code>LEInsertionList::applyInsertions</code> for each

     * entry on the insertion list.

     *

     * @param atPosition the position of the insertion

     * @param count the number of glyphs to insert

     * @param newGlyphs the address of the glyphs to insert

     *

     * @return <code>TRUE</code> if <code>LEInsertions::applyInsertions</code> should

     *         stop after applying this insertion.

     *

     * @internal

     */

    virtual le_bool applyInsertion(le_int32 atPosition, le_int32 count, LEGlyphID newGlyphs[]) = 0;

};

/**

 * This class is used to keep track of insertions to an array of

 * <code>LEGlyphIDs</code>. The insertions are kept on a linked

 * list of <code>InsertionRecords</code> so that the glyph array

 * doesn't have to be grown for each insertion. The insertions are

 * stored on the list from leftmost to rightmost to make it easier

 * to do the insertions.

 *

 * The insertions are applied to the array by calling the

 * <code>applyInsertions</code> method, which calls a client

 * supplied <code>LEInsertionCallback</code> object to actually

 * apply the individual insertions.

 *

 * @internal

 */

class LEInsertionList : public UObject

{

public:

    /**

     * Construct an empty insertion list.

     *

     * @param rightToLeft <code>TRUE</code> if the glyphs are stored

     *                    in the array in right to left order.

     *

     * @internal

     */

    LEInsertionList(le_bool rightToLeft);

    /**

     * The destructor.

     */

    ~LEInsertionList();

    /**

     * Add an entry to the insertion list.

     *

     * @param position the glyph at this position in the array will be

     *                 replaced by the new glyphs.

     * @param count the number of new glyphs

     * @param success set to an error code if the auxillary data cannot be retrieved.

     *

     * @return the address of an array in which to store the new glyphs. This will

     *         <em>not</em> be in the glyph array.

     *

     * @internal

     */

    LEGlyphID *insert(le_int32 position, le_int32 count,

        LEErrorCode &success);

    /**

     * Return the number of new glyphs that have been inserted.

     *

     * @return the number of new glyphs which have been inserted

     *

     * @internal

     */

    le_int32 getGrowAmount();

    /**

     * Call the <code>LEInsertionCallback</code> once for each

     * entry on the insertion list.

     *

     * @param callback the <code>LEInsertionCallback</code> to call for each insertion.

     *

     * @return <code>TRUE</code> if <code>callback</code> returned <code>TRUE</code> to

     *         terminate the insertion list processing.

     *

     * @internal

     */

    le_bool applyInsertions(LEInsertionCallback *callback);

    /**

     * Empty the insertion list and free all associated

     * storage.

     *

     * @internal

     */

    void reset();

    /**

     * ICU "poor man's RTTI", returns a UClassID for the actual class.

     *

     * @stable ICU 2.8

     */

    virtual UClassID getDynamicClassID() const;

    /**

     * ICU "poor man's RTTI", returns a UClassID for this class.

     *

     * @stable ICU 2.8

     */

    static UClassID getStaticClassID();

private:

    /**

     * The head of the insertion list.

     *

     * @internal

     */

    InsertionRecord *head;

    /**

     * The tail of the insertion list.

     *

     * @internal

     */

    InsertionRecord *tail;

    /**

     * The total number of new glyphs on the insertion list.

     *

     * @internal

     */

    le_int32 growAmount;

    /**

     * Set to <code>TRUE</code> if the glyphs are in right

     * to left order. Since we want the rightmost insertion

     * to be first on the list, we need to append the

     * insertions in this case. Otherwise they're prepended.

     *

     * @internal

     */

    le_bool  append;

};

U_NAMESPACE_END

#endif