Home | History | Annotate | Download | only in ico 
      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 ICOImageDecoder_h
     32 #define ICOImageDecoder_h
     33 
     34 #include "platform/image-decoders/bmp/BMPImageReader.h"
     35 
     36 namespace WebCore {
     37 
     38 class PNGImageDecoder;
     39 
     40 // This class decodes the ICO and CUR image formats.
     41 class PLATFORM_EXPORT ICOImageDecoder : public ImageDecoder {
     42 public:
     43     ICOImageDecoder(ImageSource::AlphaOption, ImageSource::GammaAndColorProfileOption, size_t maxDecodedBytes);
     44     virtual ~ICOImageDecoder();
     45 
     46     // ImageDecoder
     47     virtual String filenameExtension() const OVERRIDE { return "ico"; }
     48     virtual void setData(SharedBuffer*, bool allDataReceived) OVERRIDE;
     49     virtual bool isSizeAvailable() OVERRIDE;
     50     virtual IntSize size() const OVERRIDE;
     51     virtual IntSize frameSizeAtIndex(size_t) const OVERRIDE;
     52     virtual bool setSize(unsigned width, unsigned height) OVERRIDE;
     53     virtual size_t frameCount() OVERRIDE;
     54     virtual ImageFrame* frameBufferAtIndex(size_t) OVERRIDE;
     55     // CAUTION: setFailed() deletes all readers and decoders.  Be careful to
     56     // avoid accessing deleted memory, especially when calling this from
     57     // inside BMPImageReader!
     58     virtual bool setFailed() OVERRIDE;
     59     virtual bool hotSpot(IntPoint&) const OVERRIDE;
     60 
     61 private:
     62     enum ImageType {
     63         Unknown,
     64         BMP,
     65         PNG,
     66     };
     67 
     68     enum FileType {
     69         ICON = 1,
     70         CURSOR = 2,
     71     };
     72 
     73     struct IconDirectoryEntry {
     74         IntSize m_size;
     75         uint16_t m_bitCount;
     76         IntPoint m_hotSpot;
     77         uint32_t m_imageOffset;
     78     };
     79 
     80     // Returns true if |a| is a preferable icon entry to |b|.
     81     // Larger sizes, or greater bitdepths at the same size, are preferable.
     82     static bool compareEntries(const IconDirectoryEntry& a, const IconDirectoryEntry& b);
     83 
     84     inline uint16_t readUint16(int offset) const
     85     {
     86         return BMPImageReader::readUint16(m_data.get(), m_decodedOffset + offset);
     87     }
     88 
     89     inline uint32_t readUint32(int offset) const
     90     {
     91         return BMPImageReader::readUint32(m_data.get(), m_decodedOffset + offset);
     92     }
     93 
     94     // If the desired PNGImageDecoder exists, gives it the appropriate data.
     95     void setDataForPNGDecoderAtIndex(size_t);
     96 
     97     // Decodes the entry at |index|.  If |onlySize| is true, stops decoding
     98     // after calculating the image size.  If decoding fails but there is no
     99     // more data coming, sets the "decode failure" flag.
    100     void decode(size_t index, bool onlySize);
    101 
    102     // Decodes the directory and directory entries at the beginning of the
    103     // data, and initializes members.  Returns true if all decoding
    104     // succeeded.  Once this returns true, all entries' sizes are known.
    105     bool decodeDirectory();
    106 
    107     // Decodes the specified entry.
    108     bool decodeAtIndex(size_t);
    109 
    110     // Processes the ICONDIR at the beginning of the data.  Returns true if
    111     // the directory could be decoded.
    112     bool processDirectory();
    113 
    114     // Processes the ICONDIRENTRY records after the directory.  Keeps the
    115     // "best" entry as the one we'll decode.  Returns true if the entries
    116     // could be decoded.
    117     bool processDirectoryEntries();
    118 
    119     // Stores the hot-spot for |index| in |hotSpot| and returns true,
    120     // or returns false if there is none.
    121     bool hotSpotAtIndex(size_t index, IntPoint& hotSpot) const;
    122 
    123     // Reads and returns a directory entry from the current offset into
    124     // |data|.
    125     IconDirectoryEntry readDirectoryEntry();
    126 
    127     // Determines whether the desired entry is a BMP or PNG.  Returns true
    128     // if the type could be determined.
    129     ImageType imageTypeAtIndex(size_t);
    130 
    131     // An index into |m_data| representing how much we've already decoded.
    132     // Note that this only tracks data _this_ class decodes; once the
    133     // BMPImageReader takes over this will not be updated further.
    134     size_t m_decodedOffset;
    135 
    136     // Which type of file (ICO/CUR) this is.
    137     FileType m_fileType;
    138 
    139     // The headers for the ICO.
    140     typedef Vector<IconDirectoryEntry> IconDirectoryEntries;
    141     IconDirectoryEntries m_dirEntries;
    142 
    143     // The image decoders for the various frames.
    144     typedef Vector<OwnPtr<BMPImageReader> > BMPReaders;
    145     BMPReaders m_bmpReaders;
    146     typedef Vector<OwnPtr<PNGImageDecoder> > PNGDecoders;
    147     PNGDecoders m_pngDecoders;
    148 
    149     // Valid only while a BMPImageReader is decoding, this holds the size
    150     // for the particular entry being decoded.
    151     IntSize m_frameSize;
    152 };
    153 
    154 } // namespace WebCore
    155 
    156 #endif
    157