/* Copyright (C) 2002-2005 RealVNC Ltd. All Rights Reserved.
*
* This 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.
*
* This software 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 software; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
* USA.
*/
//
// A ZlibInStream reads from a zlib.io.InputStream
//
package com.iiordanov.tigervnc.rdr;
import com.iiordanov.jcraft.jzlib.*;
public class ZlibInStream extends InStream {
static final int defaultBufSize = 16384;
public ZlibInStream(int bufSize_)
{
bufSize = bufSize_;
b = new byte[bufSize];
bytesIn = offset = 0;
zs = new ZStream();
zs.next_in = null;
zs.next_in_index = 0;
zs.avail_in = 0;
if (zs.inflateInit() != JZlib.Z_OK) {
zs = null;
throw new Exception("ZlinInStream: inflateInit failed");
}
ptr = end = start = 0;
}
public ZlibInStream() { this(defaultBufSize); }
protected void finalize() throws Throwable {
try {
b = null;
zs.inflateEnd();
} finally {
super.finalize();
}
}
public void setUnderlying(InStream is, int bytesIn_)
{
underlying = is;
bytesIn = bytesIn_;
ptr = end = start;
}
public int pos()
{
return offset + ptr - start;
}
public void reset()
{
ptr = end = start;
if (underlying == null) return;
while (bytesIn > 0) {
decompress(true);
end = start; // throw away any data
}
underlying = null;
}
protected int overrun(int itemSize, int nItems, boolean wait)
{
if (itemSize > bufSize)
throw new Exception("ZlibInStream overrun: max itemSize exceeded");
if (underlying == null)
throw new Exception("ZlibInStream overrun: no underlying stream");
if (end - ptr != 0)
System.arraycopy(b, ptr, b, start, end - ptr);
offset += ptr - start;
end -= ptr - start;
ptr = start;
while (end - ptr < itemSize) {
if (!decompress(wait))
return 0;
}
if (itemSize * nItems > end - ptr)
nItems = (end - ptr) / itemSize;
return nItems;
}
// decompress() calls the decompressor once. Note that this won't
// necessarily generate any output data - it may just consume some input
// data. Returns false if wait is false and we would block on the underlying
// stream.
private boolean decompress(boolean wait)
{
zs.next_out = b;
zs.next_out_index = end;
zs.avail_out = start + bufSize - end;
int n = underlying.check(1, 1, wait);
if (n == 0) return false;
zs.next_in = underlying.getbuf();
zs.next_in_index = underlying.getptr();
zs.avail_in = underlying.getend() - underlying.getptr();
if (zs.avail_in > bytesIn)
zs.avail_in = bytesIn;
int rc = zs.inflate(JZlib.Z_SYNC_FLUSH);
if (rc != JZlib.Z_OK) {
throw new Exception("ZlibInStream: inflate failed");
}
bytesIn -= zs.next_in_index - underlying.getptr();
end = zs.next_out_index;
underlying.setptr(zs.next_in_index);
return true;
}
private InStream underlying;
private int bufSize;
private int offset;
private ZStream zs;
private int bytesIn;
private int start;
}