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/*
* $Id: CompressedInputStream.java,v 1.4 2004/06/08 19:05:27 dog Exp $
* Copyright (C) 2003 The Free Software Foundation
*
* This file is part of GNU inetlib, a library.
*
* GNU inetlib is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* GNU inetlib 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 for more details.
*
* You should have received a copy of the GNU 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
*
* As a special exception, if you link this library with other files to
* produce an executable, this library does not by itself cause the
* resulting executable to be covered by the GNU General Public License.
* This exception does not however invalidate any other reasons why the
* executable file might be covered by the GNU General Public License.
*/
package gnu.inet.ftp;
import java.io.InputStream;
import java.io.IOException;
import java.net.ProtocolException;
/**
* A DTP input stream that implements the FTP compressed transfer mode.
*
* @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
* @version $Revision: 1.4 $ $Date: 2004/06/08 19:05:27 $
*/
class CompressedInputStream extends DTPInputStream
{
static final int EOF = 64;
static final int RAW = 0x00;
static final int COMPRESSED = 0x80;
static final int FILLER = 0xc0;
int descriptor;
int max = -1;
int count = -1;
int state = RAW; // RAW | STATE | FILLER
int rep; // the compressed byte
int n = 0; // the number of compressed or raw bytes
CompressedInputStream (DTP dtp, InputStream in)
{
super (dtp, in);
}
public int read () throws IOException
{
if (transferComplete)
{
return -1;
}
if (count == -1)
{
readHeader ();
}
if (max < 1)
{
close ();
return -1;
}
if (n > 0 && (state == COMPRESSED || state == FILLER))
{
n--;
return rep;
}
int c = in.read ();
if (c == -1)
{
close ();
}
count++;
if (count >= max)
{
count = -1;
if (descriptor == EOF)
{
close ();
}
}
if (c == -1)
{
return c;
}
while (n == 0) // read code header
{
state = (c & 0xc0);
n = (c & 0x3f);
c = in.read ();
if (c == -1)
{
return -1;
}
}
switch (state)
{
case RAW:
break;
case COMPRESSED:
case FILLER:
rep = c;
break;
default:
throw new ProtocolException ("Illegal state: " + state);
}
n--;
return c;
}
public int read (byte[] buf) throws IOException
{
return read (buf, 0, buf.length);
}
public int read (byte[] buf, int off, int len) throws IOException
{
if (transferComplete)
{
return -1;
}
if (count == -1)
{
readHeader ();
}
if (max < 1)
{
close ();
return -1;
}
// TODO improve performance
for (int i = off; i < len; i++)
{
int c = read ();
if (c == -1)
{
close ();
return i;
}
buf[i] = (byte) c;
}
return len;
/*
int l = in.read (buf, off, len);
if (l==-1)
{
close ();
}
count += l;
if (count>=max)
{
count = -1;
if (descriptor==EOF)
{
close ();
}
}
return l;
*/
}
/**
* Reads the block header.
*/
void readHeader () throws IOException
{
descriptor = in.read ();
int max_hi = in.read ();
int max_lo = in.read ();
max = (max_hi << 8) | max_lo;
count = 0;
}
/**
* Reads the code header.
*/
void readCodeHeader () throws IOException
{
int code = in.read ();
state = (code & 0xc0);
n = (code & 0x3f);
}
}
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