1 /*
2  * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4  *
5  * This code is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 only, as
7  * published by the Free Software Foundation.  Oracle designates this
8  * particular file as subject to the "Classpath" exception as provided
9  * by Oracle in the LICENSE file that accompanied this code.
10  *
11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
16  *
17  * You should have received a copy of the GNU General Public License version
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19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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22  * or visit www.oracle.com if you need additional information or have any
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24  */
25 
26 package com.sun.imageio.plugins.gif;
27 
28 import java.io.IOException;
29 import java.util.Locale;
30 import java.util.Iterator;
31 import javax.imageio.ImageReader;
32 import javax.imageio.metadata.IIOMetadataFormat;
33 import javax.imageio.metadata.IIOMetadataFormatImpl;
34 import javax.imageio.spi.ImageReaderSpi;
35 import javax.imageio.stream.ImageInputStream;
36 
37 public class GIFImageReaderSpi extends ImageReaderSpi {
38 
39     private static final String vendorName = "Oracle Corporation";
40 
41     private static final String version = "1.0";
42 
43     private static final String[] names = { "gif", "GIF" };
44 
45     private static final String[] suffixes = { "gif" };
46 
47     private static final String[] MIMETypes = { "image/gif" };
48 
49     private static final String readerClassName =
50         "com.sun.imageio.plugins.gif.GIFImageReader";
51 
52     private static final String[] writerSpiNames = {
53         "com.sun.imageio.plugins.gif.GIFImageWriterSpi"
54     };
55 
GIFImageReaderSpi()56     public GIFImageReaderSpi() {
57         super(vendorName,
58               version,
59               names,
60               suffixes,
61               MIMETypes,
62               readerClassName,
63               new Class<?>[] { ImageInputStream.class },
64               writerSpiNames,
65               true,
66               GIFStreamMetadata.nativeMetadataFormatName,
67               "com.sun.imageio.plugins.gif.GIFStreamMetadataFormat",
68               null, null,
69               true,
70               GIFImageMetadata.nativeMetadataFormatName,
71               "com.sun.imageio.plugins.gif.GIFImageMetadataFormat",
72               null, null
73               );
74     }
75 
getDescription(Locale locale)76     public String getDescription(Locale locale) {
77         return "Standard GIF image reader";
78     }
79 
canDecodeInput(Object input)80     public boolean canDecodeInput(Object input) throws IOException {
81         if (!(input instanceof ImageInputStream)) {
82             return false;
83         }
84 
85         ImageInputStream stream = (ImageInputStream)input;
86         byte[] b = new byte[6];
87         stream.mark();
88         stream.readFully(b);
89         stream.reset();
90 
91         return b[0] == 'G' && b[1] == 'I' && b[2] == 'F' && b[3] == '8' &&
92             (b[4] == '7' || b[4] == '9') && b[5] == 'a';
93     }
94 
createReaderInstance(Object extension)95     public ImageReader createReaderInstance(Object extension) {
96         return new GIFImageReader(this);
97     }
98 
99 }
100