If I'm lucky, I might have a sipb-xen-vnc-client package, too

[invirt/packages/invirt-vnc-client.git] / code / ZlibInStream.java

diff --git a/code/ZlibInStream.java b/code/ZlibInStream.java
new file mode 100644 (file)
index 0000000..b6e3659
--- /dev/null
+++ b/code/ZlibInStream.java
@@ -0,0 +1,111 @@
+/* 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;
+}