1 files changed, 54 insertions, 0 deletions
diff --git a/conversations/src/main/java/eu/siacs/conversations/utils/zlib/ZLibInputStream.java b/conversations/src/main/java/eu/siacs/conversations/utils/zlib/ZLibInputStream.java
new file mode 100644
index 00000000..b777c10c
--- /dev/null
+++ b/conversations/src/main/java/eu/siacs/conversations/utils/zlib/ZLibInputStream.java
@@ -0,0 +1,54 @@
+package eu.siacs.conversations.utils.zlib;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.zip.Inflater;
+import java.util.zip.InflaterInputStream;
+
+/**
+ * ZLibInputStream is a zlib and input stream compatible version of an
+ * InflaterInputStream. This class solves the incompatibility between
+ * {@link InputStream#available()} and {@link InflaterInputStream#available()}.
+ */
+public class ZLibInputStream extends InflaterInputStream {
+
+	/**
+	 * Construct a ZLibInputStream, reading data from the underlying stream.
+	 * 
+	 * @param is
+	 *            The {@code InputStream} to read data from.
+	 * @throws IOException
+	 *             If an {@code IOException} occurs.
+	 */
+	public ZLibInputStream(InputStream is) throws IOException {
+		super(is, new Inflater(), 512);
+	}
+
+	/**
+	 * Provide a more InputStream compatible version of available. A return
+	 * value of 1 means that it is likly to read one byte without blocking, 0
+	 * means that the system is known to block for more input.
+	 * 
+	 * @return 0 if no data is available, 1 otherwise
+	 * @throws IOException
+	 */
+	@Override
+	public int available() throws IOException {
+		/*
+		 * This is one of the funny code blocks. InflaterInputStream.available
+		 * violates the contract of InputStream.available, which breaks kXML2.
+		 * 
+		 * I'm not sure who's to blame, oracle/sun for a broken api or the
+		 * google guys for mixing a sun bug with a xml reader that can't handle
+		 * it....
+		 * 
+		 * Anyway, this simple if breaks suns distorted reality, but helps to
+		 * use the api as intended.
+		 */
+		if (inf.needsInput()) {
+			return 0;
+		}
+		return super.available();
+	}
+
+}