File indexing completed on 2024-06-16 05:01:51

 /****************************************************************************
 **
 ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
 ** All rights reserved.
 ** Contact: Nokia Corporation (qt-info@nokia.com)
 **
 ** This file is part of the Qt Messaging Framework.
 **
 ** $QT_BEGIN_LICENSE:LGPL$
 ** GNU Lesser General Public License Usage
 ** This file may be used under the terms of the GNU Lesser General Public
 ** License version 2.1 as published by the Free Software Foundation and
 ** appearing in the file LICENSE.LGPL included in the packaging of this
 ** file. Please review the following information to ensure the GNU Lesser
 ** General Public License version 2.1 requirements will be met:
 ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
 **
 ** In addition, as a special exception, Nokia gives you certain additional
 ** rights. These rights are described in the Nokia Qt LGPL Exception
 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
 **
 ** GNU General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU General
 ** Public License version 3.0 as published by the Free Software Foundation
 ** and appearing in the file LICENSE.GPL included in the packaging of this
 ** file. Please review the following information to ensure the GNU General
 ** Public License version 3.0 requirements will be met:
 ** http://www.gnu.org/copyleft/gpl.html.
 **
 ** Other Usage
 ** Alternatively, this file may be used in accordance with the terms and
 ** conditions contained in a signed written agreement between you and Nokia.
 **
 **
 **
 **
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/
 
 #ifndef STREAMS_RFC1951_H
 #define STREAMS_RFC1951_H
 
 #include <QIODevice>
 
 #include <zlib.h>
 
 namespace Streams {
 
 /* From RFC4978 The IMAP COMPRESS:   
    "When using the zlib library (see [RFC1951]), the functions
    deflateInit2(), deflate(), inflateInit2(), and inflate() suffice to
    implement this extension.  The windowBits value must be in the range
    -8 to -15, or else deflateInit2() uses the wrong format.
    deflateParams() can be used to improve compression rate and resource
    use.  The Z_FULL_FLUSH argument to deflate() can be used to clear the
    dictionary (the receiving peer does not need to do anything)."
    
    Total zlib mem use is 176KB plus a 'few kilobytes' per connection that uses COMPRESS:
    96KB for deflate, 24KB for 3x8KB buffers, 32KB plus a 'few' kilobytes for inflate.
 */
 
 class Rfc1951Compressor
 {
 public:
     explicit Rfc1951Compressor(int chunkSize = 8192);
     ~Rfc1951Compressor();
 
     bool write(QIODevice *out, QByteArray *in);
 
 private:
     int _chunkSize;
     z_stream _zStream;
     char *_buffer;
 };
 
 class Rfc1951Decompressor
 {
 public:
     explicit Rfc1951Decompressor(int chunkSize = 8192);
     ~Rfc1951Decompressor();
 
     bool consume(QIODevice *in);
     bool canReadLine() const;
     QByteArray readLine();
     QByteArray read(qint64 maxSize);
 
 private:
     int _chunkSize;
     z_stream _zStream;
     QByteArray _inBuffer;
     char *_stagingBuffer;
     QByteArray _output;
 };
 
 }
 
 #endif