michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef __JPCNTX_H__
michael@0: #define __JPCNTX_H__
michael@0: 
michael@0: #define NUM_OF_CATEGORY 6
michael@0: 
michael@0: #include "nscore.h" 
michael@0: 
michael@0: #define ENOUGH_REL_THRESHOLD  100
michael@0: #define MAX_REL_THRESHOLD     1000
michael@0: 
michael@0: //hiragana frequency category table
michael@0: extern const uint8_t jp2CharContext[83][83];
michael@0: 
michael@0: class JapaneseContextAnalysis
michael@0: {
michael@0: public:
michael@0:   JapaneseContextAnalysis() {Reset(false);}
michael@0: 
michael@0:   void HandleData(const char* aBuf, uint32_t aLen);
michael@0: 
michael@0:   void HandleOneChar(const char* aStr, uint32_t aCharLen)
michael@0:   {
michael@0:     int32_t order;
michael@0: 
michael@0:     //if we received enough data, stop here   
michael@0:     if (mTotalRel > MAX_REL_THRESHOLD)   mDone = true;
michael@0:     if (mDone)       return;
michael@0:      
michael@0:     //Only 2-bytes characters are of our interest
michael@0:     order = (aCharLen == 2) ? GetOrder(aStr) : -1;
michael@0:     if (order != -1 && mLastCharOrder != -1)
michael@0:     {
michael@0:       mTotalRel++;
michael@0:       //count this sequence to its category counter
michael@0:       mRelSample[jp2CharContext[mLastCharOrder][order]]++;
michael@0:     }
michael@0:     mLastCharOrder = order;
michael@0:   }
michael@0: 
michael@0:   float GetConfidence(void);
michael@0:   void      Reset(bool aIsPreferredLanguage);
michael@0:   bool GotEnoughData() {return mTotalRel > ENOUGH_REL_THRESHOLD;}
michael@0: 
michael@0: protected:
michael@0:   virtual int32_t GetOrder(const char* str, uint32_t *charLen) = 0;
michael@0:   virtual int32_t GetOrder(const char* str) = 0;
michael@0: 
michael@0:   //category counters, each integer counts sequences in its category
michael@0:   uint32_t mRelSample[NUM_OF_CATEGORY];
michael@0: 
michael@0:   //total sequence received
michael@0:   uint32_t mTotalRel;
michael@0: 
michael@0:   //Number of sequences needed to trigger detection
michael@0:   uint32_t mDataThreshold;
michael@0:   
michael@0:   //The order of previous char
michael@0:   int32_t  mLastCharOrder;
michael@0: 
michael@0:   //if last byte in current buffer is not the last byte of a character, we
michael@0:   //need to know how many byte to skip in next buffer.
michael@0:   uint32_t mNeedToSkipCharNum;
michael@0: 
michael@0:   //If this flag is set to true, detection is done and conclusion has been made
michael@0:   bool     mDone;
michael@0: };
michael@0: 
michael@0: 
michael@0: class SJISContextAnalysis : public JapaneseContextAnalysis
michael@0: {
michael@0:   //SJISContextAnalysis(){};
michael@0: protected:
michael@0:   int32_t GetOrder(const char* str, uint32_t *charLen);
michael@0: 
michael@0:   int32_t GetOrder(const char* str)
michael@0:   {
michael@0:     //We only interested in Hiragana, so first byte is '\202'
michael@0:     if (*str == '\202' && 
michael@0:           (unsigned char)*(str+1) >= (unsigned char)0x9f && 
michael@0:           (unsigned char)*(str+1) <= (unsigned char)0xf1)
michael@0:       return (unsigned char)*(str+1) - (unsigned char)0x9f;
michael@0:     return -1;
michael@0:   }
michael@0: };
michael@0: 
michael@0: class EUCJPContextAnalysis : public JapaneseContextAnalysis
michael@0: {
michael@0: protected:
michael@0:   int32_t GetOrder(const char* str, uint32_t *charLen);
michael@0:   int32_t GetOrder(const char* str)
michael@0:     //We only interested in Hiragana, so first byte is '\244'
michael@0:   {
michael@0:     if (*str == '\244' &&
michael@0:           (unsigned char)*(str+1) >= (unsigned char)0xa1 &&
michael@0:           (unsigned char)*(str+1) <= (unsigned char)0xf3)
michael@0:       return (unsigned char)*(str+1) - (unsigned char)0xa1;
michael@0:     return -1;
michael@0:   }
michael@0: };
michael@0: 
michael@0: #endif /* __JPCNTX_H__ */
michael@0: