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 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
  * The contents of this file are subject to the Mozilla Public License Version
  * 1.1 (the "License"); you may not use this file except in compliance with
  * the License. You may obtain a copy of the License at
  * http://www.mozilla.org/MPL/
  *
  * Software distributed under the License is distributed on an "AS IS" basis,
  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  * for the specific language governing rights and limitations under the
  * License.
  *
  * The Original Code is Mozilla Communicator client code.
  *
  * The Initial Developer of the Original Code is
  * Netscape Communications Corporation.
  * Portions created by the Initial Developer are Copyright (C) 1998
  * the Initial Developer. All Rights Reserved.
  *
  * Contributor(s):
  *
  * Alternatively, the contents of this file may be used under the terms of
  * either the GNU General Public License Version 2 or later (the "GPL"), or
  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  * in which case the provisions of the GPL or the LGPL are applicable instead
  * of those above. If you wish to allow use of your version of this file only
  * under the terms of either the GPL or the LGPL, and not to allow others to
  * use your version of this file under the terms of the MPL, indicate your
  * decision by deleting the provisions above and replace them with the notice
  * and other provisions required by the GPL or the LGPL. If you do not delete
  * the provisions above, a recipient may use your version of this file under
  * the terms of any one of the MPL, the GPL or the LGPL.
  *
  * ***** END LICENSE BLOCK ***** */
 
 #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 char jp2CharContext[83][83];
 
 class JapaneseContextAnalysis
 {
 public:
   JapaneseContextAnalysis() {Reset();}
   virtual ~JapaneseContextAnalysis() {}
 
   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[int(jp2CharContext[mLastCharOrder][order])]++;
     }
     mLastCharOrder = order;
   };
 
   float GetConfidence();
   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 sequence 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__ */