001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.io;
003
004import java.io.File;
005import java.io.FileInputStream;
006import java.io.FileOutputStream;
007import java.io.IOException;
008import java.io.InputStream;
009import java.io.OutputStream;
010import java.net.URL;
011import java.nio.charset.StandardCharsets;
012import java.util.zip.GZIPOutputStream;
013import java.util.zip.ZipOutputStream;
014
015import org.apache.commons.compress.compressors.bzip2.BZip2CompressorOutputStream;
016import org.openstreetmap.josm.tools.Utils;
017
018/**
019 * An enum representing the compression type of a resource.
020 */
021public enum Compression {
022    /**
023     * no compression
024     */
025    NONE,
026    /**
027     * bzip2 compression
028     */
029    BZIP2,
030    /**
031     * gzip compression
032     */
033    GZIP,
034    /**
035     * zip compression
036     */
037    ZIP;
038
039    /**
040     * Determines the compression type depending on the suffix of {@code name}.
041     * @param name File name including extension
042     * @return the compression type
043     */
044    public static Compression byExtension(String name) {
045        return name != null && name.endsWith(".gz")
046                ? GZIP
047                : name != null && (name.endsWith(".bz2") || name.endsWith(".bz"))
048                ? BZIP2
049                : name != null && name.endsWith(".zip")
050                ? ZIP
051                : NONE;
052    }
053
054    /**
055     * Returns an un-compressing {@link InputStream} for {@code in}.
056     * @param in raw input stream
057     * @return un-compressing input stream
058     *
059     * @throws IOException if any I/O error occurs
060     */
061    public InputStream getUncompressedInputStream(InputStream in) throws IOException {
062        switch (this) {
063            case BZIP2:
064                return Utils.getBZip2InputStream(in);
065            case GZIP:
066                return Utils.getGZipInputStream(in);
067            case ZIP:
068                return Utils.getZipInputStream(in);
069            case NONE:
070            default:
071                return in;
072        }
073    }
074
075    /**
076     * Returns an un-compressing {@link InputStream} for the {@link File} {@code file}.
077     * @param file file
078     * @return un-compressing input stream
079     * @throws IOException if any I/O error occurs
080     */
081    @SuppressWarnings("resource")
082    public static InputStream getUncompressedFileInputStream(File file) throws IOException {
083        return byExtension(file.getName()).getUncompressedInputStream(new FileInputStream(file));
084    }
085
086    /**
087     * Returns an un-compressing {@link InputStream} for the {@link URL} {@code url}.
088     * @param url URL
089     * @return un-compressing input stream
090     *
091     * @throws IOException if any I/O error occurs
092     */
093    public static InputStream getUncompressedURLInputStream(URL url) throws IOException {
094        return Utils.openURLAndDecompress(url, true);
095    }
096
097    /**
098     * Returns a compressing {@link OutputStream} for {@code out}.
099     * @param out raw output stream
100     * @return compressing output stream
101     *
102     * @throws IOException if any I/O error occurs
103     */
104    public OutputStream getCompressedOutputStream(OutputStream out) throws IOException {
105        switch (this) {
106            case BZIP2:
107                return new BZip2CompressorOutputStream(out);
108            case GZIP:
109                return new GZIPOutputStream(out);
110            case ZIP:
111                return new ZipOutputStream(out, StandardCharsets.UTF_8);
112            case NONE:
113            default:
114                return out;
115        }
116    }
117
118    /**
119     * Returns a compressing {@link OutputStream} for the {@link File} {@code file}.
120     * @param file file
121     * @return compressing output stream
122     *
123     * @throws IOException if any I/O error occurs
124     */
125    @SuppressWarnings("resource")
126    public static OutputStream getCompressedFileOutputStream(File file) throws IOException {
127        return byExtension(file.getName()).getCompressedOutputStream(new FileOutputStream(file));
128    }
129}