textcodecdetector.h

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#pragma once


class QByteArray;

namespace edbee {

class TextCodec;

class TextCodecDetector
{

public:

    static TextCodec* globalPreferedCodec();
    static void setGlobalPreferedCodec( TextCodec* codec );


    explicit TextCodecDetector( const QByteArray* buffer=0,  TextCodec* preferedCodec=0 );
    explicit TextCodecDetector( const char* buffer, int length=0, TextCodec* preferedCodec=0 );
    virtual ~TextCodecDetector();


    virtual TextCodec* detectCodec();

    virtual void setBuffer( const char* buf, int length )
    {
        bufferRef_ = buf;
        bufferLength_ = length;
    }

    virtual const char*buffer() const { return bufferRef_; }

    virtual int bufferLength() { return bufferLength_; }

    virtual void setPreferedCodec( TextCodec* codec=0 );
    virtual TextCodec* preferedCodec() { return preferedCodecRef_; }


    virtual void setFallbackCodec( TextCodec* codec=0 );
    virtual TextCodec* fallbackCodec() const { return fallbackCodecRef_; }



protected:

    virtual bool isContinuationChar( char b) { return /*-128 <= b && */ b <= -65; }

    virtual bool  isTwoBytesSequence(char b) { return -64 <= b && b <= -33; }

    virtual bool isThreeBytesSequence(char b) { return -32 <= b && b <= -17; }

    virtual bool  isFourBytesSequence(char b) { return -16 <= b && b <= -9; }

    virtual bool  isFiveBytesSequence(char b) { return -8 <= b && b <= -5; }

    // If the byte has the form 1110xxx, then it's the first byte of a six-bytes sequence character.
    virtual bool isSixBytesSequence(char b){  return -4 <= b && b <= -3; }

public:
    static bool hasUTF8Bom( const char* buffer, int length );
    static bool hasUTF16LEBom( const char* buffer, int length );
    static bool hasUTF16BEBom( const char* buffer, int length );
    static bool hasUTF32LEBom( const char* buffer, int length );
    static bool hasUTF32BEBom( const char* buffer, int length );


private:

    //const QByteArray *bufferRef_;   ///< A reference to the current buffer of data
    const char* bufferRef_;         
    int bufferLength_;              

    TextCodec* preferedCodecRef_;  
    TextCodec* fallbackCodecRef_;   


};

} // edbee