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.formats.webp.chunks;
18
19 import java.io.IOException;
20 import java.io.PrintWriter;
21 import java.nio.ByteOrder;
22 import java.nio.charset.StandardCharsets;
23
24 import org.apache.commons.imaging.ImagingException;
25 import org.apache.commons.imaging.common.BinaryFileParser;
26 import org.apache.commons.imaging.internal.SafeOperations;
27
28 /**
29 * A WebP image is composed of several chunks. This is the base class for the chunks, used by the parser.
30 *
31 * @see <a href="https://developers.google.com/speed/webp/docs/riff_container">WebP Container Specification</a>
32 * @since 1.0-alpha4
33 */
34 public abstract class WebPChunk extends BinaryFileParser {
35 private final int type;
36 private final int size;
37 protected final byte[] bytes;
38 private final int chunkSize;
39
40 /**
41 * Create a new WebP chunk.
42 *
43 * @param type chunk type.
44 * @param size chunk size.
45 * @param bytes chunk data.
46 * @throws ImagingException if the chunk data and the size provided do not match.
47 */
48 WebPChunk(final int type, final int size, final byte[] bytes) throws ImagingException {
49 super(ByteOrder.LITTLE_ENDIAN);
50
51 if (size != bytes.length) {
52 throw new ImagingException("Chunk size must match bytes length");
53 }
54
55 this.type = type;
56 this.size = size;
57 this.bytes = bytes;
58
59 // if chunk size is odd, a single padding byte is added
60 final int padding = size % 2 != 0 ? 1 : 0;
61
62 // Chunk FourCC (4 bytes) + Chunk Size (4 bytes) + Chunk Payload (n bytes) + Padding
63 this.chunkSize = SafeOperations.add(4, 4, size, padding);
64 }
65
66 /**
67 * Print the chunk to the given stream.
68 *
69 * @param pw a stream to write to.
70 * @param offset chunk offset.
71 * @throws ImagingException if the image is invalid.
72 * @throws IOException if it fails to write to the given stream.
73 */
74 public void dump(final PrintWriter pw, final int offset) throws ImagingException, IOException {
75 pw.printf("Chunk %s at offset %s, length %d%n, payload size %d%n", getTypeDescription(), offset >= 0 ? String.valueOf(offset) : "unknown",
76 getChunkSize(), getPayloadSize());
77 }
78
79 /**
80 * @return a copy of the chunk data as bytes.
81 */
82 public byte[] getBytes() {
83 return bytes.clone();
84 }
85
86 /**
87 * @return the chunk size.
88 */
89 public int getChunkSize() {
90 return chunkSize;
91 }
92
93 /**
94 * @return the payload size.
95 */
96 public int getPayloadSize() {
97 return size;
98 }
99
100 /**
101 * @return the chunk type.
102 */
103 public int getType() {
104 return type;
105 }
106
107 /**
108 * @return the description of the chunk type.
109 */
110 public String getTypeDescription() {
111 return new String(new byte[] { (byte) (type & 0xff), (byte) (type >> 8 & 0xff), (byte) (type >> 16 & 0xff), (byte) (type >> 24 & 0xff) },
112 StandardCharsets.UTF_8);
113 }
114 }