1 files changed, 126 insertions, 0 deletions
diff --git a/src/org/jivesoftware/smack/compression/Java7ZlibInputOutputStream.java b/src/org/jivesoftware/smack/compression/Java7ZlibInputOutputStream.java
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+++ b/src/org/jivesoftware/smack/compression/Java7ZlibInputOutputStream.java
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+/**
+ * Copyright 2013 Florian Schmaus
+ *
+ * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jivesoftware.smack.compression;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.zip.Deflater;
+import java.util.zip.DeflaterOutputStream;
+import java.util.zip.Inflater;
+import java.util.zip.InflaterInputStream;
+
+/**
+ * This class provides XMPP "zlib" compression with the help of the Deflater class of the Java API. Note that the method
+ * needed is available since Java7, so it will only work with Java7 or higher (hence it's name).
+ * 
+ * @author Florian Schmaus
+ * @see <a
+ * href="http://docs.oracle.com/javase/7/docs/api/java/util/zip/Deflater.html#deflate(byte[], int, int, int)">The
+ * required deflate() method</a>
+ * 
+ */
+public class Java7ZlibInputOutputStream extends XMPPInputOutputStream {
+    private final static Method method;
+    private final static boolean supported;
+    private final static int compressionLevel = Deflater.DEFAULT_STRATEGY;
+
+    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);
+    }
+
+    public Java7ZlibInputOutputStream() {
+        compressionMethod = "zlib";
+    }
+
+    @Override
+    public boolean isSupported() {
+        return supported;
+    }
+
+    @Override
+    public InputStream getInputStream(InputStream inputStream) {
+        return new InflaterInputStream(inputStream, new Inflater(), 512) {
+            /**
+             * Provide a more InputStream compatible version. A return value of 1 means that it is likely 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 {
+                /*
+                 * aSmack related remark (where KXmlParser is used):
+                 * 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();
+            }
+        };
+    }
+
+    @Override
+    public OutputStream getOutputStream(OutputStream outputStream) {
+        return new DeflaterOutputStream(outputStream, new Deflater(compressionLevel)) {
+            public void flush() throws IOException {
+                if (!supported) {
+                    super.flush();
+                    return;
+                }
+                int count = 0;
+                if (!def.needsInput()) {
+                    do {
+                        count = def.deflate(buf, 0, buf.length);
+                        out.write(buf, 0, count);
+                    } while (count > 0);
+                    out.flush();
+                }
+                try {
+                    do {
+                        count = (Integer) method.invoke(def, buf, 0, buf.length, 2);
+                        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();
+            }
+        };
+    }
+
+}