/*

 * Copyright 2001 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

#ifndef _BUFFER_

#define _BUFFER_

// A Buffer is the backing store for the IOBuf abstraction and

// supports producer-consumer filling and draining.

class Buffer {

public:

  Buffer(int bufSize);

  ~Buffer();

  char* fillPos();   // Position of the place where buffer should be filled

  int   remaining(); // Number of bytes that can be placed starting at fillPos

  int   size();      // Size of the buffer

  // Move up fill position by amount (decreases remaining()); returns

  // false if not enough space

  bool  incrFillPos(int amt);

  // Read single byte (0..255); returns -1 if no data available.

  int   readByte();

  // Read multiple bytes, non-blocking (this buffer does not define a

  // fill mechanism), into provided buffer. Returns number of bytes read.

  int   readBytes(char* buf, int len);

  // Access to drain position. Be very careful using this.

  char* drainPos();

  int   drainRemaining();

  bool  incrDrainPos(int amt);

  // Compact buffer, removing already-consumed input. This must be

  // called periodically to yield the illusion of an infinite buffer.

  void  compact();

private:

  Buffer(const Buffer&);

  Buffer& operator=(const Buffer&);

  char* buf;

  int   sz;

  int   fill;

  int   drain;

};

#endif // #defined _BUFFER_