PositionableStream.h

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/*
 * PositionableStream.h
 *
 * Smalltalk like class library for C++
 * Abstract stream with positioning feature. Header.
 *
 * Copyright (c) 2003 Milan Cermak
 */
/*
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#ifndef __POSITIONABLESTREAM_H
#define __POSITIONABLESTREAM_H

#include <stlib/Stream.h>

namespace Core {

class SequenceableCollection;
class String;

class PositionableStream : public Stream
{
  protected:
    SequenceableCollection *collection;
    long _position;
    long read_limit;
    long write_limit;

  protected:
    /* Initialize/release protocol */
    virtual void initialize(SequenceableCollection *coll);

  public:
    /* Class-accessing protocol */
    virtual String *className(void) const;

    /* Accessing protocol */
    virtual SequenceableCollection *contents(void);
    virtual Object *next(void) abstract;
    virtual SequenceableCollection *next(long items)
      { return Stream::next(items); }
    virtual SequenceableCollection *next(long items, SequenceableCollection *newColl, long index);

    virtual bool peekFor(Object *obj);

    /* Positioning protocol */
    virtual long position(void);
    virtual void position(long position);
    virtual void reset(void);
    virtual void skip(long length);

    /* Testing protocol */
    virtual bool atEnd(void);
    virtual bool isEmpty(void);
    virtual bool notEmpty(void);
    virtual bool isBinary(void);

    /* Private protocol */
    virtual bool basicAtEnd(void);

  protected:
    /* Private protocol */
    virtual SequenceableCollection *contentSpeciesFor(long items);
};

};

#endif /* __POSITIONABLESTREAM_H */

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