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 * The Original Code is Mozilla Communicator client code.

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#ifndef __JPCNTX_H__

#define __JPCNTX_H__

#define NUM_OF_CATEGORY 6

#include "nscore.h" 

#define ENOUGH_REL_THRESHOLD  100

#define MAX_REL_THRESHOLD     1000

//hiragana frequency category table

extern const PRUint8 jp2CharContext[83][83];

class JapaneseContextAnalysis

{

public:

  JapaneseContextAnalysis() {Reset();}

  void HandleData(const char* aBuf, PRUint32 aLen);

  void HandleOneChar(const char* aStr, PRUint32 aCharLen)

  {

    PRInt32 order;

    //if we received enough data, stop here   

    if (mTotalRel > MAX_REL_THRESHOLD)   mDone = PR_TRUE;

    if (mDone)       return;

    //Only 2-bytes characters are of our interest

    order = (aCharLen == 2) ? GetOrder(aStr) : -1;

    if (order != -1 && mLastCharOrder != -1)

    {

      mTotalRel++;

      //count this sequence to its category counter

      mRelSample[jp2CharContext[mLastCharOrder][order]]++;

    }

    mLastCharOrder = order;

  }

  float GetConfidence(PRBool aIsPreferredLanguage);

  void      Reset(void);

  void      SetOpion(){}

  PRBool GotEnoughData() {return mTotalRel > ENOUGH_REL_THRESHOLD;}

protected:

  virtual PRInt32 GetOrder(const char* str, PRUint32 *charLen) = 0;

  virtual PRInt32 GetOrder(const char* str) = 0;

  //category counters, each integer counts sequences in its category

  PRUint32 mRelSample[NUM_OF_CATEGORY];

  //total sequence received

  PRUint32 mTotalRel;

  //The order of previous char

  PRInt32  mLastCharOrder;

  //if last byte in current buffer is not the last byte of a character, we

  //need to know how many byte to skip in next buffer.

  PRUint32 mNeedToSkipCharNum;

  //If this flag is set to PR_TRUE, detection is done and conclusion has been made

  PRBool   mDone;

};

class SJISContextAnalysis : public JapaneseContextAnalysis

{

  //SJISContextAnalysis(){};

protected:

  PRInt32 GetOrder(const char* str, PRUint32 *charLen);

  PRInt32 GetOrder(const char* str)

  {

    //We only interested in Hiragana, so first byte is '\202'

    if (*str == '\202' && 

          (unsigned char)*(str+1) >= (unsigned char)0x9f && 

          (unsigned char)*(str+1) <= (unsigned char)0xf1)

      return (unsigned char)*(str+1) - (unsigned char)0x9f;

    return -1;

  }

};

class EUCJPContextAnalysis : public JapaneseContextAnalysis

{

protected:

  PRInt32 GetOrder(const char* str, PRUint32 *charLen);

  PRInt32 GetOrder(const char* str)

    //We only interested in Hiragana, so first byte is '\244'

  {

    if (*str == '\244' &&

          (unsigned char)*(str+1) >= (unsigned char)0xa1 &&

          (unsigned char)*(str+1) <= (unsigned char)0xf3)

      return (unsigned char)*(str+1) - (unsigned char)0xa1;

    return -1;

  }

};

#endif /* __JPCNTX_H__ */