[hornetq-commits] JBoss hornetq SVN: r9937 - branches/Branch_Large_Message_Compression/src/main/org/hornetq/utils.

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Author: gaohoward
Date: 2010-11-29 09:15:10 -0500 (Mon, 29 Nov 2010)
New Revision: 9937

Added:
   branches/Branch_Large_Message_Compression/src/main/org/hornetq/utils/DeflaterReader.java
Log:
added a zip class impl that directly use Deflater


Added: branches/Branch_Large_Message_Compression/src/main/org/hornetq/utils/DeflaterReader.java
===================================================================
--- branches/Branch_Large_Message_Compression/src/main/org/hornetq/utils/DeflaterReader.java	                        (rev 0)
+++ branches/Branch_Large_Message_Compression/src/main/org/hornetq/utils/DeflaterReader.java	2010-11-29 14:15:10 UTC (rev 9937)
@@ -0,0 +1,158 @@
+/*
+ * Copyright 2010 Red Hat, Inc.
+ * Red Hat licenses this file to you 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.hornetq.utils;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.zip.Deflater;
+
+/**
+ * A DeflaterReader
+ * The reader takes an inputstream and compress it.
+ *
+ *
+ */
+public class DeflaterReader
+{
+   private Deflater deflater = new Deflater();
+   private boolean isFinished = false;
+   private boolean compressDone = false;
+
+   private InputStream input;
+   
+   public DeflaterReader(InputStream inData)
+   {
+      input = inData;
+   }
+   
+   public int read(byte[] buffer) throws IOException
+   {
+      return read(buffer, 0, buffer.length);
+   }
+   
+   /**
+    * Try to fill the buffer with compressed bytes. Except the last effective read,
+    * this method always returns with a full buffer of compressed data.
+    * 
+    * @param buffer the buffer to fill compressed bytes
+    * @return the number of bytes really filled, -1 indicates end.
+    * @throws IOException 
+    */
+   public int read(byte[] buffer, int offset, int len) throws IOException
+   {
+      if (compressDone)
+      {
+         return -1;
+      }
+      
+      //buffer for reading input stream
+      byte[] readBuffer = new byte[2 * len];
+
+      int n = 0;
+      int read = 0;
+
+      while (len > 0)
+      {
+         n = deflater.deflate(buffer, offset, len);
+         if (n == 0)
+         {
+            if (isFinished)
+            {
+               deflater.end();
+               compressDone = true;
+               break;
+            }
+            else if (deflater.needsInput())
+            {
+               System.err.println("need input so read input");
+               // read some data from inputstream
+               int m = input.read(readBuffer);
+               System.err.println("original data read: " + m);
+               if (m == -1)
+               {
+                  System.err.println("no more original data, finish deflater, now offset " + offset + " len " + len);
+                  
+                  deflater.finish();
+                  isFinished = true;
+               }
+               else
+               {
+                  deflater.setInput(readBuffer, 0, m);
+               }
+            }
+            else
+            {
+               deflater.finish();
+               isFinished = true;
+            }
+         }
+         else
+         {
+            read += n;
+            offset += n;
+            len -= n;
+         }
+         
+      }
+      return read;
+   }
+   
+   public static void main(String[] args) throws IOException
+   {
+      String inputString = "blahblahblah??blahblahblahblahblah??blablahblah??blablahblah??bla";
+      byte[] input = inputString.getBytes("UTF-8");
+
+      ByteArrayInputStream inputStream = new ByteArrayInputStream(input);
+      
+      DeflaterReader reader = new DeflaterReader(inputStream);
+      
+      byte[] buffer = new byte[7];
+      
+      int n = reader.read(buffer);
+      
+      System.err.println("first read: " + n);
+      
+      while (n != -1)
+      {
+         System.err.println("==>read n " + n + " values: " + getBytesString(buffer));
+         n = reader.read(buffer);
+      }
+      
+      System.err.println("compressed.");
+      
+      System.err.println("now verify");
+      
+      byte[] output = new byte[30];
+      Deflater compresser = new Deflater();
+      compresser.setInput(input);
+      compresser.finish();
+      int compressedDataLength = compresser.deflate(output);
+      System.err.println("compress len: " + compressedDataLength);
+      System.err.println("commpress data: " + getBytesString(output));
+
+   }
+   
+   static String getBytesString(byte[] array)
+   {
+      StringBuffer bf = new StringBuffer();
+      for (byte b : array)
+      {
+         int val = b & 0xFF;
+         bf.append(val + " ");
+      }
+      return bf.toString();
+   }
+   
+}