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Viewing changes to src/java/org/apache/commons/compress/compressors/bzip2/BZip2Compressor.java

  • Committer: Bazaar Package Importer
  • Author(s): Torsten Werner
  • Date: 2007-12-17 15:17:09 UTC
  • Revision ID: james.westby@ubuntu.com-20071217151709-dqfo6iq1zxyssgf6
Tags: upstream-0~svn604876
Import upstream version 0~svn604876

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src/java/org/apache/commons/compress/compressors/bzip2/BZip2Compressor.java
 
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/*
 
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 * Licensed to the Apache Software Foundation (ASF) under one
 
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 * or more contributor license agreements.  See the NOTICE file
 
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 * distributed with this work for additional information
 
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 * regarding copyright ownership.  The ASF licenses this file
 
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 * to you under the Apache License, Version 2.0 (the
 
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 * "License"); you may not use this file except in compliance
 
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 * with the License.  You may obtain a copy of the License at
 
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 *
 
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 * http://www.apache.org/licenses/LICENSE-2.0
 
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 *
 
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 * Unless required by applicable law or agreed to in writing,
 
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 * software distributed under the License is distributed on an
 
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 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 
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 * KIND, either express or implied.  See the License for the
 
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 * specific language governing permissions and limitations
 
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 * under the License.
 
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 */
 
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package org.apache.commons.compress.compressors.bzip2;
 
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import java.io.FileInputStream;
 
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import java.io.FileNotFoundException;
 
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import java.io.FileOutputStream;
 
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import java.io.IOException;
 
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import java.io.InputStream;
 
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import java.io.OutputStream;
 
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import org.apache.commons.compress.AbstractCompressor;
 
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import org.apache.commons.compress.CompressException;
 
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import org.apache.commons.compress.CompressUtils;
 
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/**
 
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 * Implementation of the Compressor Interface for BZip2. 
 
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 * 
 
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 * @author christian.grobmeier
 
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 */
 
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public class BZip2Compressor extends AbstractCompressor {
 
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        /* Header BZ as byte-Array */
 
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        private static final byte[] HEADER = new byte[]{(byte)'B', (byte)'Z'};
 
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        /* Name of this implementation */
 
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        private static final String NAME = "bz2";
 
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        /* Default file extension*/
 
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        private static String DEFAULT_FILE_EXTENSION = "bz2";
 
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        /**
 
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         * Constructor. 
 
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         */
 
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        public BZip2Compressor() {
 
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                super();
 
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        }
 
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        /* (non-Javadoc)
 
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         * @see org.apache.commons.compress.Compressor#compress(java.io.FileInputStream, java.io.FileOutputStream)
 
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         */
 
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        public void compressTo(FileInputStream inputStream, FileOutputStream outputStream) throws CompressException {
 
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                BZip2OutputStream outputBZStream = null;
 
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                try {
 
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                        outputBZStream = getPackedOutput( outputStream );
 
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                        CompressUtils.copy( inputStream, outputBZStream );
 
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                } catch (FileNotFoundException e) {
 
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                        throw new CompressException("File could not be found", e);
 
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                } catch (IOException e) {
 
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                        throw new CompressException("An IO Exception occured", e);
 
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                } finally {
 
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                        try {
 
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                                outputBZStream.close();
 
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                        } catch (IOException e1) {
 
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                                throw new CompressException("An IO Exception occured while closing the streams", e1);
 
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                        }
 
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                }
 
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        }
 
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        /* 
 
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         * This decompress method uses a special InputStream Class for BZ2
 
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         * @see org.apache.commons.compress.Compressor#decompress(java.io.FileInputStream, java.io.FileOutputStream)
 
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         */
 
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        public void decompressTo(FileInputStream input, FileOutputStream outputStream) 
 
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                throws CompressException {
 
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                BZip2InputStream inputStream = null;
 
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                try {
 
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                        inputStream = getPackedInput( input );
 
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                        CompressUtils.copy( inputStream, outputStream );
 
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                } catch (IOException e) {
 
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                        throw new CompressException("An I/O Exception has occured", e);
 
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                }
 
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        }
 
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        /**
 
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         * Skips the 'BZ' header bytes. required by the BZip2InputStream class.
 
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         * @param input input stream
 
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         * @return {@link BZip2InputStream} instance
 
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         * @throws IOException if an IO error occurs
 
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         */
 
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        private BZip2InputStream getPackedInput( final InputStream input )
 
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                throws IOException {
 
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                // skips the 'BZ' header bytes required by the BZip2InputStream class
 
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                input.read();
 
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                input.read();
 
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                return new BZip2InputStream( input );
 
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        }
 
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        /**
 
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         * Writes a 'BZ' header to the output stream, and creates a
 
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         * BZip2OutputStream object ready for use, as required by the
 
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         * BZip2OutputStream class.
 
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         * 
 
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         * @param output {@link Output} stream to add a header to
 
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         * @return {@link BZip2OutputStream} ready to write to
 
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         * @throws IOException if an IO error occurs
 
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         */
 
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        private BZip2OutputStream getPackedOutput( final OutputStream output )
 
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                throws IOException {
 
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                output.write( HEADER );
 
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                return new BZip2OutputStream( output );
 
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        }
 
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        /* (non-Javadoc)
 
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         * @see org.apache.commons.compress.Compressor#getHeader()
 
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         */
 
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        public byte[] getHeader() {
 
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                return HEADER;
 
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        }
 
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        /* (non-Javadoc)
 
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         * @see org.apache.commons.compress.Compressor#getName()
 
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         */
 
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        public String getName() {
 
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                return NAME;
 
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        }
 
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        /* (non-Javadoc)
 
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         * @see org.apache.commons.compress.AbstractCompressor#getDefaultFileExtension()
 
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         */
 
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        public String getDefaultFileExtension() {
 
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                return DEFAULT_FILE_EXTENSION;
 
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        }
 
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}