1/*
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29 */
30
31#ifndef ICOImageDecoder_h
32#define ICOImageDecoder_h
33
34#include "BMPImageReader.h"
35
36namespace WebCore {
37
38    class PNGImageDecoder;
39
40    // This class decodes the ICO and CUR image formats.
41    class ICOImageDecoder : public ImageDecoder {
42    public:
43        ICOImageDecoder(ImageSource::AlphaOption, ImageSource::GammaAndColorProfileOption);
44        virtual ~ICOImageDecoder();
45
46        // ImageDecoder
47        virtual String filenameExtension() const { return "ico"; }
48        virtual void setData(SharedBuffer*, bool allDataReceived);
49        virtual bool isSizeAvailable();
50        virtual IntSize size() const;
51        virtual IntSize frameSizeAtIndex(size_t) const;
52        virtual bool setSize(unsigned width, unsigned height);
53        virtual size_t frameCount();
54        virtual ImageFrame* frameBufferAtIndex(size_t);
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();
59        virtual bool hotSpot(IntPoint&) const;
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