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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(ImageSource::AlphaOption, ImageSource::GammaAndColorProfileOption);
     43 
     44         // ImageDecoder
     45         virtual String filenameExtension() const { return "bmp"; }
     46         virtual void setData(SharedBuffer*, bool allDataReceived);
     47         virtual bool isSizeAvailable();
     48         virtual ImageFrame* frameBufferAtIndex(size_t index);
     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();
     53 
     54     private:
     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 WebCore
     84 
     85 #endif
     86