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/* 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
//
public class ZlibInStream extends InStream {
static final int defaultBufSize = 16384;
public ZlibInStream(int bufSize_) {
bufSize = bufSize_;
b = new byte[bufSize];
ptr = end = ptrOffset = 0;
inflater = new java.util.zip.Inflater();
}
public ZlibInStream() { this(defaultBufSize); }
public void setUnderlying(InStream is, int bytesIn_) {
underlying = is;
bytesIn = bytesIn_;
ptr = end = 0;
}
public void reset() throws Exception {
ptr = end = 0;
if (underlying == null) return;
while (bytesIn > 0) {
decompress();
end = 0; // throw away any data
}
underlying = null;
}
public int pos() { return ptrOffset + ptr; }
protected int overrun(int itemSize, int nItems) throws Exception {
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, 0, end - ptr);
ptrOffset += ptr;
end -= ptr;
ptr = 0;
while (end < itemSize) {
decompress();
}
if (itemSize * nItems > end)
nItems = end / 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 void decompress() throws Exception {
try {
underlying.check(1);
int avail_in = underlying.getend() - underlying.getptr();
if (avail_in > bytesIn)
avail_in = bytesIn;
if (inflater.needsInput()) {
inflater.setInput(underlying.getbuf(), underlying.getptr(), avail_in);
}
int n = inflater.inflate(b, end, bufSize - end);
end += n;
if (inflater.needsInput()) {
bytesIn -= avail_in;
underlying.setptr(underlying.getptr() + avail_in);
}
} catch (java.util.zip.DataFormatException e) {
throw new Exception("ZlibInStream: inflate failed");
}
}
private InStream underlying;
private int bufSize;
private int ptrOffset;
private java.util.zip.Inflater inflater;
private int bytesIn;
}
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