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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()
     44     : ImageDecoder()
     45     , m_allDataReceived(false)
     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     m_allDataReceived = allDataReceived;
     57     if (m_reader)
     58         m_reader->setData(data);
     59 }
     60 
     61 bool BMPImageDecoder::isSizeAvailable()
     62 {
     63     if (!ImageDecoder::isSizeAvailable() && !failed())
     64         decodeWithCheckForDataEnded(true);
     65 
     66     return ImageDecoder::isSizeAvailable();
     67 }
     68 
     69 RGBA32Buffer* BMPImageDecoder::frameBufferAtIndex(size_t index)
     70 {
     71     if (index)
     72         return 0;
     73 
     74     if (m_frameBufferCache.isEmpty())
     75         m_frameBufferCache.resize(1);
     76 
     77     RGBA32Buffer* buffer = &m_frameBufferCache.first();
     78     if (buffer->status() != RGBA32Buffer::FrameComplete && !failed())
     79         decodeWithCheckForDataEnded(false);
     80     return buffer;
     81 }
     82 
     83 void BMPImageDecoder::decodeWithCheckForDataEnded(bool onlySize)
     84 {
     85     if (failed())
     86         return;
     87 
     88     // If we couldn't decode the image but we've received all the data, decoding
     89     // has failed.
     90     if (!decode(onlySize) && m_allDataReceived)
     91         setFailed();
     92 }
     93 
     94 bool BMPImageDecoder::decode(bool onlySize)
     95 {
     96     size_t imgDataOffset = 0;
     97     if ((m_decodedOffset < sizeOfFileHeader)
     98         && !processFileHeader(&imgDataOffset))
     99         return false;
    100 
    101     if (!m_reader) {
    102         m_reader.set(new BMPImageReader(this, m_decodedOffset, imgDataOffset,
    103                                         false));
    104         m_reader->setData(m_data.get());
    105     }
    106 
    107     if (!m_frameBufferCache.isEmpty())
    108         m_reader->setBuffer(&m_frameBufferCache.first());
    109 
    110     return m_reader->decodeBMP(onlySize);
    111 }
    112 
    113 bool BMPImageDecoder::processFileHeader(size_t* imgDataOffset)
    114 {
    115     ASSERT(imgDataOffset);
    116 
    117     // Read file header.
    118     ASSERT(!m_decodedOffset);
    119     if (m_data->size() < sizeOfFileHeader)
    120         return false;
    121     const uint16_t fileType =
    122         (m_data->data()[0] << 8) | static_cast<uint8_t>(m_data->data()[1]);
    123     *imgDataOffset = readUint32(10);
    124     m_decodedOffset = sizeOfFileHeader;
    125 
    126     // See if this is a bitmap filetype we understand.
    127     enum {
    128         BMAP = 0x424D,  // "BM"
    129         // The following additional OS/2 2.x header values (see
    130         // http://www.fileformat.info/format/os2bmp/egff.htm ) aren't widely
    131         // decoded, and are unlikely to be in much use.
    132         /*
    133         ICON = 0x4943,  // "IC"
    134         POINTER = 0x5054,  // "PT"
    135         COLORICON = 0x4349,  // "CI"
    136         COLORPOINTER = 0x4350,  // "CP"
    137         BITMAPARRAY = 0x4241,  // "BA"
    138         */
    139     };
    140     if (fileType != BMAP) {
    141         setFailed();
    142         return false;
    143     }
    144 
    145     return true;
    146 }
    147 
    148 } // namespace WebCore
    149