1/*
2 * Copyright (c) 2008, 2009, Google Inc. All rights reserved.
3 *
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5 * modification, are permitted provided that the following conditions are
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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
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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
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21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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29 */
30
31#ifndef ICOImageDecoder_h
32#define ICOImageDecoder_h
33
34#include "platform/image-decoders/bmp/BMPImageReader.h"
35
36namespace blink {
37
38class PNGImageDecoder;
39
40// This class decodes the ICO and CUR image formats.
41class PLATFORM_EXPORT ICOImageDecoder : public ImageDecoder {
42public:
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
61private:
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 blink
155
156#endif
157