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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 "platform/image-decoders/bmp/BMPImageReader.h"
35 #include "wtf/OwnPtr.h"
36 
37 namespace blink {
38 
39 // This class decodes the BMP image format.
40 class PLATFORM_EXPORT BMPImageDecoder : public ImageDecoder {
41 public:
42     BMPImageDecoder(ImageSource::AlphaOption, ImageSource::GammaAndColorProfileOption, size_t maxDecodedBytes);
43 
44     // ImageDecoder
filenameExtension()45     virtual String filenameExtension() const OVERRIDE { return "bmp"; }
46     virtual void setData(SharedBuffer*, bool allDataReceived) OVERRIDE;
47     virtual bool isSizeAvailable() OVERRIDE;
48     virtual ImageFrame* frameBufferAtIndex(size_t) OVERRIDE;
49     // CAUTION: setFailed() deletes |m_reader|.  Be careful to avoid
50     // accessing deleted memory, especially when calling this from inside
51     // BMPImageReader!
52     virtual bool setFailed() OVERRIDE;
53 
54 private:
readUint32(int offset)55     inline uint32_t readUint32(int offset) const
56     {
57         return BMPImageReader::readUint32(m_data.get(), m_decodedOffset + offset);
58     }
59 
60     // Decodes the image.  If |onlySize| is true, stops decoding after
61     // calculating the image size. If decoding fails but there is no more
62     // data coming, sets the "decode failure" flag.
63     void decode(bool onlySize);
64 
65     // Decodes the image.  If |onlySize| is true, stops decoding after
66     // calculating the image size. Returns whether decoding succeeded.
67     bool decodeHelper(bool onlySize);
68 
69     // Processes the file header at the beginning of the data.  Sets
70     // |imgDataOffset| based on the header contents. Returns true if the
71     // file header could be decoded.
72     bool processFileHeader(size_t& imgDataOffset);
73 
74     // An index into |m_data| representing how much we've already decoded.
75     // Note that this only tracks data _this_ class decodes; once the
76     // BMPImageReader takes over this will not be updated further.
77     size_t m_decodedOffset;
78 
79     // The reader used to do most of the BMP decoding.
80     OwnPtr<BMPImageReader> m_reader;
81 };
82 
83 } // namespace blink
84 
85 #endif
86