1 package nom.tam.fits.compress;
2
3 /*
4 * #%L
5 * nom.tam FITS library
6 * %%
7 * Copyright (C) 1996 - 2024 nom-tam-fits
8 * %%
9 * This is free and unencumbered software released into the public domain.
10 *
11 * Anyone is free to copy, modify, publish, use, compile, sell, or
12 * distribute this software, either in source code form or as a compiled
13 * binary, for any purpose, commercial or non-commercial, and by any
14 * means.
15 *
16 * In jurisdictions that recognize copyright laws, the author or authors
17 * of this software dedicate any and all copyright interest in the
18 * software to the public domain. We make this dedication for the benefit
19 * of the public at large and to the detriment of our heirs and
20 * successors. We intend this dedication to be an overt act of
21 * relinquishment in perpetuity of all present and future rights to this
22 * software under copyright law.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
27 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
28 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
29 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
30 * OTHER DEALINGS IN THE SOFTWARE.
31 * #L%
32 */
33
34 import java.io.IOException;
35 import java.io.InputStream;
36
37 /**
38 * (<i>for internal use</i>) UNIX compressed (<code>.Z</code>) input stream decompression. You can use this class to
39 * decompress files that have been compressed with the UNIX <b>compress</b> tool (or via <b>gzip</b>) and have the
40 * characteristic <code>.Z</code> file name extension. Or, use {@link CompressionManager} to automatically detect the
41 * type of compression used. This class uses the Apache <b>commons-compress</b> package to perform the decompression.
42 *
43 * @see CompressionManager
44 */
45 public class ZCompressionProvider implements ICompressProvider {
46
47 private static final int Z_COMPRESS_MAGIC_BYTE1 = 0x1f;
48
49 private static final int Z_COMPRESS_MAGIC_BYTE2 = 0x9d;
50
51 private static final int PRIORITY = 5;
52
53 @SuppressWarnings("deprecation")
54 @Override
55 public InputStream decompress(InputStream in) throws IOException {
56 try {
57 return CompressionLibLoaderProtection.createZStream(in);
58 } catch (IOException e) {
59 throw e;
60 } catch (Exception e) {
61 throw new IOException(e);
62 }
63 }
64
65 @Override
66 public int priority() {
67 return PRIORITY;
68 }
69
70 @Override
71 public boolean provides(int mag1, int mag2) {
72 return mag1 == Z_COMPRESS_MAGIC_BYTE1 && mag2 == Z_COMPRESS_MAGIC_BYTE2;
73 }
74 }