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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 #include "config.h"
     32 #include "BMPImageDecoder.h"
     33 
     34 #include "BMPImageReader.h"
     35 
     36 namespace WebCore {
     37 
     38 // Number of bits in .BMP used to store the file header (doesn't match
     39 // "sizeof(BMPImageDecoder::BitmapFileHeader)" since we omit some fields and
     40 // don't pack).
     41 static const size_t sizeOfFileHeader = 14;
     42 
     43 BMPImageDecoder::BMPImageDecoder(ImageSource::AlphaOption alphaOption,
     44                                  ImageSource::GammaAndColorProfileOption gammaAndColorProfileOption)
     45     : ImageDecoder(alphaOption, gammaAndColorProfileOption)
     46     , m_decodedOffset(0)
     47 {
     48 }
     49 
     50 void BMPImageDecoder::setData(SharedBuffer* data, bool allDataReceived)
     51 {
     52     if (failed())
     53         return;
     54 
     55     ImageDecoder::setData(data, allDataReceived);
     56     if (m_reader)
     57         m_reader->setData(data);
     58 }
     59 
     60 bool BMPImageDecoder::isSizeAvailable()
     61 {
     62     if (!ImageDecoder::isSizeAvailable())
     63         decode(true);
     64 
     65     return ImageDecoder::isSizeAvailable();
     66 }
     67 
     68 ImageFrame* BMPImageDecoder::frameBufferAtIndex(size_t index)
     69 {
     70     if (index)
     71         return 0;
     72 
     73     if (m_frameBufferCache.isEmpty()) {
     74         m_frameBufferCache.resize(1);
     75         m_frameBufferCache.first().setPremultiplyAlpha(m_premultiplyAlpha);
     76     }
     77 
     78     ImageFrame* buffer = &m_frameBufferCache.first();
     79     if (buffer->status() != ImageFrame::FrameComplete)
     80         decode(false);
     81     return buffer;
     82 }
     83 
     84 bool BMPImageDecoder::setFailed()
     85 {
     86     m_reader.clear();
     87     return ImageDecoder::setFailed();
     88 }
     89 
     90 void BMPImageDecoder::decode(bool onlySize)
     91 {
     92     if (failed())
     93         return;
     94 
     95     // If we couldn't decode the image but we've received all the data, decoding
     96     // has failed.
     97     if (!decodeHelper(onlySize) && isAllDataReceived())
     98         setFailed();
     99     // If we're done decoding the image, we don't need the BMPImageReader
    100     // anymore.  (If we failed, |m_reader| has already been cleared.)
    101     else if (!m_frameBufferCache.isEmpty() && (m_frameBufferCache.first().status() == ImageFrame::FrameComplete))
    102         m_reader.clear();
    103 }
    104 
    105 bool BMPImageDecoder::decodeHelper(bool onlySize)
    106 {
    107     size_t imgDataOffset = 0;
    108     if ((m_decodedOffset < sizeOfFileHeader) && !processFileHeader(&imgDataOffset))
    109         return false;
    110 
    111     if (!m_reader) {
    112         m_reader.set(new BMPImageReader(this, m_decodedOffset, imgDataOffset, false));
    113         m_reader->setData(m_data.get());
    114     }
    115 
    116     if (!m_frameBufferCache.isEmpty())
    117         m_reader->setBuffer(&m_frameBufferCache.first());
    118 
    119     return m_reader->decodeBMP(onlySize);
    120 }
    121 
    122 bool BMPImageDecoder::processFileHeader(size_t* imgDataOffset)
    123 {
    124     ASSERT(imgDataOffset);
    125 
    126     // Read file header.
    127     ASSERT(!m_decodedOffset);
    128     if (m_data->size() < sizeOfFileHeader)
    129         return false;
    130     const uint16_t fileType = (m_data->data()[0] << 8) | static_cast<uint8_t>(m_data->data()[1]);
    131     *imgDataOffset = readUint32(10);
    132     m_decodedOffset = sizeOfFileHeader;
    133 
    134     // See if this is a bitmap filetype we understand.
    135     enum {
    136         BMAP = 0x424D,  // "BM"
    137         // The following additional OS/2 2.x header values (see
    138         // http://www.fileformat.info/format/os2bmp/egff.htm ) aren't widely
    139         // decoded, and are unlikely to be in much use.
    140         /*
    141         ICON = 0x4943,  // "IC"
    142         POINTER = 0x5054,  // "PT"
    143         COLORICON = 0x4349,  // "CI"
    144         COLORPOINTER = 0x4350,  // "CP"
    145         BITMAPARRAY = 0x4241,  // "BA"
    146         */
    147     };
    148     return (fileType == BMAP) || setFailed();
    149 }
    150 
    151 } // namespace WebCore
    152