1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.imaging.common;
18
19 import java.io.ByteArrayOutputStream;
20 import java.io.IOException;
21 import java.util.zip.DataFormatException;
22 import java.util.zip.DeflaterOutputStream;
23 import java.util.zip.Inflater;
24
25 import org.apache.commons.imaging.ImagingException;
26
27 /**
28 * <p>
29 * Utility class to compress/decompress bytes using the ZLIB deflate/inflate compression.
30 * </p>
31 *
32 * <p>
33 * <a href="https://www.ietf.org/rfc/rfc1951.txt">RFC 1951 - DEFLATE Compressed Data Format Specification version 1.3</a>
34 * </p>
35 */
36 public final class ZlibDeflate {
37
38 /**
39 * Compress the byte[] using ZLIB deflate compression.
40 *
41 * @param bytes The bytes to compress
42 *
43 * @return The compressed bytes.
44 * @throws ImagingException if the bytes could not be compressed.
45 * @see DeflaterOutputStream
46 */
47 public static byte[] compress(final byte[] bytes) throws ImagingException {
48 final ByteArrayOutputStream out = new ByteArrayOutputStream(Allocator.checkByteArray(bytes.length / 2));
49 try (DeflaterOutputStream compressOut = new DeflaterOutputStream(out)) {
50 compressOut.write(bytes);
51 } catch (final IOException e) {
52 throw new ImagingException("Unable to compress image", e);
53 }
54 return out.toByteArray();
55 }
56
57 /**
58 * Compress the byte[] using ZLIB deflate decompression.
59 *
60 * @param bytes The bytes to decompress
61 * @param expectedSize The expected size of the decompressed byte[].
62 *
63 * @return The decompressed bytes.
64 * @throws ImagingException if the bytes could not be decompressed.
65 * @see Inflater
66 */
67 public static byte[] decompress(final byte[] bytes, final int expectedSize) throws ImagingException {
68 try {
69 final Inflater inflater = new Inflater();
70 inflater.setInput(bytes);
71 final byte[] result = Allocator.byteArray(expectedSize);
72 inflater.inflate(result);
73 return result;
74 } catch (final DataFormatException e) {
75 throw new ImagingException("Unable to decompress image", e);
76 }
77 }
78
79 private ZlibDeflate() {
80 // empty
81 }
82 }