org.hornetq.utils.InflaterWriter Maven / Gradle / Ivy

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/*
 * Copyright 2005-2014 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.IOException;
import java.io.OutputStream;
import java.util.zip.DataFormatException;
import java.util.zip.Inflater;

/**
 * A InflaterWriter
 * 
 * This class takes an OutputStream. Compressed bytes
 * can directly be written into this class. The class will
 * decompress the bytes and write them to the output stream.
 * 
 * Not for concurrent use.
 *
 * @author Howard Gao
 */
public class InflaterWriter extends OutputStream
{
   private final Inflater inflater = new Inflater();

   private final OutputStream output;

   private final byte[] writeBuffer = new byte[1024];

   private int writePointer = 0;

   private final byte[] outputBuffer = new byte[writeBuffer.length * 2];

   public InflaterWriter(final OutputStream output)
   {
      this.output = output;
   }

   /*
    * Write a compressed byte.
    */
   @Override
   public void write(final int b) throws IOException
   {
      writeBuffer[writePointer] = (byte)(b & 0xFF);
      writePointer++;

      if (writePointer == writeBuffer.length)
      {
         writePointer = 0;
         try
         {
            doWrite();
         }
         catch (DataFormatException e)
         {
            IOException ie = new IOException("Error decompressing data");
            ie.initCause(e);
            throw ie;
         }
      }
   }

   @Override
   public void close() throws IOException
   {
      if (writePointer > 0)
      {
         inflater.setInput(writeBuffer, 0, writePointer);
         try
         {
            int n = inflater.inflate(outputBuffer);
            while (n > 0)
            {
               output.write(outputBuffer, 0, n);
               n = inflater.inflate(outputBuffer);
            }
            output.close();
         }
         catch (DataFormatException e)
         {
            IOException io = new IOException(e.getMessage());
            io.initCause(e);
            throw io;
         }
      }
   }

   private void doWrite() throws DataFormatException, IOException
   {
      inflater.setInput(writeBuffer);
      int n = inflater.inflate(outputBuffer);

      while (n > 0)
      {
         output.write(outputBuffer, 0, n);
         n = inflater.inflate(outputBuffer);
      }
   }

}