1 files changed, 95 insertions, 0 deletions
diff --git a/conversations/src/main/java/eu/siacs/conversations/utils/zlib/ZLibOutputStream.java b/conversations/src/main/java/eu/siacs/conversations/utils/zlib/ZLibOutputStream.java
new file mode 100644
index 00000000..8b3f5e68
--- /dev/null
+++ b/conversations/src/main/java/eu/siacs/conversations/utils/zlib/ZLibOutputStream.java
@@ -0,0 +1,95 @@
+package eu.siacs.conversations.utils.zlib;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.security.NoSuchAlgorithmException;
+import java.util.zip.Deflater;
+import java.util.zip.DeflaterOutputStream;
+
+/**
+ * <p>
+ * Android 2.2 includes Java7 FLUSH_SYNC option, which will be used by this
+ * Implementation, preferable via reflection. The @hide was remove in API level
+ * 19. This class might thus go away in the future.
+ * </p>
+ * <p>
+ * Please use {@link ZLibOutputStream#SUPPORTED} to check for flush
+ * compatibility.
+ * </p>
+ */
+public class ZLibOutputStream extends DeflaterOutputStream {
+
+	/**
+	 * The reflection based flush method.
+	 */
+
+	private final static Method method;
+	/**
+	 * SUPPORTED is true if a flush compatible method exists.
+	 */
+	public final static boolean SUPPORTED;
+
+	/**
+	 * Static block to initialize {@link #SUPPORTED} and {@link #method}.
+	 */
+	static {
+		Method m = null;
+		try {
+			m = Deflater.class.getMethod("deflate", byte[].class, int.class,
+					int.class, int.class);
+		} catch (SecurityException e) {
+		} catch (NoSuchMethodException e) {
+		}
+		method = m;
+		SUPPORTED = (method != null);
+	}
+
+	/**
+	 * Create a new ZLib compatible output stream wrapping the given low level
+	 * stream. ZLib compatiblity means we will send a zlib header.
+	 * 
+	 * @param os
+	 *            OutputStream The underlying stream.
+	 * @throws IOException
+	 *             In case of a lowlevel transfer problem.
+	 * @throws NoSuchAlgorithmException
+	 *             In case of a {@link Deflater} error.
+	 */
+	public ZLibOutputStream(OutputStream os) throws IOException,
+			NoSuchAlgorithmException {
+		super(os, new Deflater(Deflater.BEST_COMPRESSION));
+	}
+
+	/**
+	 * Flush the given stream, preferring Java7 FLUSH_SYNC if available.
+	 * 
+	 * @throws IOException
+	 *             In case of a lowlevel exception.
+	 */
+	@Override
+	public void flush() throws IOException {
+		if (!SUPPORTED) {
+			super.flush();
+			return;
+		}
+		try {
+			int count = 0;
+			do {
+				count = (Integer) method.invoke(def, buf, 0, buf.length, 3);
+				if (count > 0) {
+					out.write(buf, 0, count);
+				}
+			} while (count > 0);
+		} catch (IllegalArgumentException e) {
+			throw new IOException("Can't flush");
+		} catch (IllegalAccessException e) {
+			throw new IOException("Can't flush");
+		} catch (InvocationTargetException e) {
+			throw new IOException("Can't flush");
+		}
+		super.flush();
+	}
+
+}