michael@0: /* -*- Mode: C; tab-width: 4; 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: // for S-JIS encoding, obeserve characteristic:
michael@0: // 1, kana character (or hankaku?) often have hight frequency of appereance
michael@0: // 2, kana character often exist in group
michael@0: // 3, certain combination of kana is never used in japanese language
michael@0: 
michael@0: #include "nsSJISProber.h"
michael@0: #include "nsDebug.h"
michael@0: 
michael@0: void  nsSJISProber::Reset(void)
michael@0: {
michael@0:   mCodingSM->Reset(); 
michael@0:   mState = eDetecting;
michael@0:   mContextAnalyser.Reset(mIsPreferredLanguage);
michael@0:   mDistributionAnalyser.Reset(mIsPreferredLanguage);
michael@0: }
michael@0: 
michael@0: nsProbingState nsSJISProber::HandleData(const char* aBuf, uint32_t aLen)
michael@0: {
michael@0:   NS_ASSERTION(aLen, "HandleData called with empty buffer");
michael@0:   nsSMState codingState;
michael@0: 
michael@0:   for (uint32_t i = 0; i < aLen; i++)
michael@0:   {
michael@0:     codingState = mCodingSM->NextState(aBuf[i]);
michael@0:     if (codingState == eItsMe)
michael@0:     {
michael@0:       mState = eFoundIt;
michael@0:       break;
michael@0:     }
michael@0:     if (codingState == eStart)
michael@0:     {
michael@0:       uint32_t charLen = mCodingSM->GetCurrentCharLen();
michael@0:       if (i == 0)
michael@0:       {
michael@0:         mLastChar[1] = aBuf[0];
michael@0:         mContextAnalyser.HandleOneChar(mLastChar+2-charLen, charLen);
michael@0:         mDistributionAnalyser.HandleOneChar(mLastChar, charLen);
michael@0:       }
michael@0:       else
michael@0:       {
michael@0:         mContextAnalyser.HandleOneChar(aBuf+i+1-charLen, charLen);
michael@0:         mDistributionAnalyser.HandleOneChar(aBuf+i-1, charLen);
michael@0:       }
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   mLastChar[0] = aBuf[aLen-1];
michael@0: 
michael@0:   if (mState == eDetecting)
michael@0:     if (mContextAnalyser.GotEnoughData() && GetConfidence() > SHORTCUT_THRESHOLD)
michael@0:       mState = eFoundIt;
michael@0: 
michael@0:   return mState;
michael@0: }
michael@0: 
michael@0: float nsSJISProber::GetConfidence(void)
michael@0: {
michael@0:   float contxtCf = mContextAnalyser.GetConfidence();
michael@0:   float distribCf = mDistributionAnalyser.GetConfidence();
michael@0: 
michael@0:   return (contxtCf > distribCf ? contxtCf : distribCf);
michael@0: }
michael@0: