xbmimagedecoder.h

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

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 */

#ifndef XBMImageDecoder_h
#define XBMImageDecoder_h

#include "config.h"
#include <string>
#include "ImageDecoder.h"

namespace WebCore {

    // This class decodes the XBM image format.
    class XBMImageDecoder : public ImageDecoder {
    public:
        XBMImageDecoder();
        virtual ~XBMImageDecoder() {}

        virtual String filenameExtension() const { return "xbm"; }

        virtual void setData(SharedBuffer* data, bool allDataReceived);
        // Whether or not the size information has been decoded yet.
        virtual bool isSizeAvailable() const;
        virtual RGBA32Buffer* frameBufferAtIndex(size_t index);

    private:
        // Restricts image size to something "reasonable".
        // This protects agains ridiculously large XBMs and prevents bad things
        // like overflow of m_bitsDecoded.
        static const int maxDimension = 65535;

        // In X10, an array of type "short" is used to declare the image bits,
        // but in X11, the type is "char".
        enum DataType {
            Unknown,
            X10,
            X11,
        };

        bool decodeHeader();
        bool decodeDatum(uint16_t* result);
        bool decodeData();
        void decodeXBM(bool sizeOnly);

        std::string m_xbmString;  // Null-terminated copy of the XBM data.
        size_t m_decodeOffset;    // The current offset in m_xbmString for decoding.
        bool m_allDataReceived;
        bool m_decodedHeader;
        enum DataType m_dataType;
        int m_bitsDecoded;
    };

} // namespace WebCore

#endif