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1 /*
2  * Copyright (c) 2008, 2009, Google Inc. All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions are
6  * met:
7  *
8  *     * Redistributions of source code must retain the above copyright
9  * notice, this list of conditions and the following disclaimer.
10  *     * Redistributions in binary form must reproduce the above
11  * copyright notice, this list of conditions and the following disclaimer
12  * in the documentation and/or other materials provided with the
13  * distribution.
14  *     * Neither the name of Google Inc. nor the names of its
15  * contributors may be used to endorse or promote products derived from
16  * this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #ifndef BMPImageDecoder_h
32 #define BMPImageDecoder_h
33 
34 #include "BMPImageReader.h"
35 #include <wtf/OwnPtr.h>
36 
37 namespace WebCore {
38 
39     // This class decodes the BMP image format.
40     class BMPImageDecoder : public ImageDecoder {
41     public:
42         BMPImageDecoder();
43 
44         // ImageDecoder
filenameExtension()45         virtual String filenameExtension() const { return "bmp"; }
46         virtual void setData(SharedBuffer*, bool allDataReceived);
47         virtual bool isSizeAvailable();
48         virtual RGBA32Buffer* frameBufferAtIndex(size_t index);
49 
50     private:
readUint32(int offset)51         inline uint32_t readUint32(int offset) const
52         {
53             return BMPImageReader::readUint32(m_data.get(),
54                                               m_decodedOffset + offset);
55         }
56 
57         // Decodes the image.  If |onlySize| is true, stops decoding after
58         // calculating the image size.  If decoding fails but there is no more
59         // data coming, sets the "decode failure" flag.
60         void decodeWithCheckForDataEnded(bool onlySize);
61 
62         // Decodes the image.  If |onlySize| is true, stops decoding after
63         // calculating the image size.  Returns whether decoding succeeded.
64         // NOTE: Used internally by decodeWithCheckForDataEnded().  Other people
65         // should not call this.
66         bool decode(bool onlySize);
67 
68         // Processes the file header at the beginning of the data.  Sets
69         // |*imgDataOffset| based on the header contents.  Returns true if the
70         // file header could be decoded.
71         bool processFileHeader(size_t* imgDataOffset);
72 
73         // True if we've seen all the data.
74         bool m_allDataReceived;
75 
76         // An index into |m_data| representing how much we've already decoded.
77         // Note that this only tracks data _this_ class decodes; once the
78         // BMPImageReader takes over this will not be updated further.
79         size_t m_decodedOffset;
80 
81         // The reader used to do most of the BMP decoding.
82         OwnPtr<BMPImageReader> m_reader;
83     };
84 
85 } // namespace WebCore
86 
87 #endif
88