001/*
002 * Syncany, www.syncany.org
003 * Copyright (C) 2011-2016 Philipp C. Heckel <philipp.heckel@gmail.com> 
004 *
005 * This program is free software: you can redistribute it and/or modify
006 * it under the terms of the GNU General Public License as published by
007 * the Free Software Foundation, either version 3 of the License, or
008 * (at your option) any later version.
009 *
010 * This program is distributed in the hope that it will be useful,
011 * but WITHOUT ANY WARRANTY; without even the implied warranty of
012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
013 * GNU General Public License for more details.
014 *
015 * You should have received a copy of the GNU General Public License
016 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
017 */
018package org.syncany.chunk;
019
020import java.io.IOException;
021import java.io.InputStream;
022import java.io.OutputStream;
023import java.util.Map;
024import java.util.zip.Deflater;
025import java.util.zip.GZIPInputStream;
026import java.util.zip.GZIPOutputStream;
027
028/**
029 * Implements a {@link Transformer} that transforms the input/output stream
030 * using the Gzip compression algorithm.
031 * 
032 * @author Philipp C. Heckel <philipp.heckel@gmail.com>
033 */
034public class GzipTransformer extends Transformer {
035    public static final String TYPE = "gzip";
036        private int level;
037    
038    public GzipTransformer() {
039        this(Deflater.DEFAULT_COMPRESSION, null);
040    }
041    
042    public GzipTransformer(Transformer nextTransformer) {
043        this(Deflater.DEFAULT_COMPRESSION, nextTransformer);
044    }
045    
046    public GzipTransformer(int level, Transformer nextTransformer) {
047        super(nextTransformer);
048        this.level = level;
049    }
050    
051    @Override
052    public void init(Map<String, String> settings) throws Exception {
053        // Nothing here         
054    }
055    
056    @Override
057    public OutputStream createOutputStream(OutputStream out) throws IOException {
058        if (nextTransformer == null) {
059            return new GZIPOutputStreamEx(out, level);
060        }
061        else {
062            return new GZIPOutputStreamEx(nextTransformer.createOutputStream(out), level);
063        }
064    }
065
066    @Override
067    public InputStream createInputStream(InputStream in) throws IOException {
068        if (nextTransformer == null) {
069            return new GZIPInputStream(in);
070        }
071        else {
072            return new GZIPInputStream(nextTransformer.createInputStream(in));
073        }
074    }
075    
076    public static class GZIPOutputStreamEx extends GZIPOutputStream {
077        /**
078         * Level is 1-9 -- 1 being best speed, and 9 being best compression
079         */
080        public GZIPOutputStreamEx(OutputStream out, int level) throws IOException {
081            super(out);
082            def.setLevel(level);
083        }
084    }    
085    
086    @Override
087    public String toString() {
088        return (nextTransformer == null) ? "Gzip" : "Gzip-"+nextTransformer;
089    }    
090}