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: #include "nsUTF8Prober.h"
michael@0: 
michael@0: void  nsUTF8Prober::Reset(void)
michael@0: {
michael@0:   mCodingSM->Reset(); 
michael@0:   mNumOfMBChar = 0;
michael@0:   mState = eDetecting;
michael@0: }
michael@0: 
michael@0: nsProbingState nsUTF8Prober::HandleData(const char* aBuf, uint32_t aLen)
michael@0: {
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:       if (mCodingSM->GetCurrentCharLen() >= 2)
michael@0:         mNumOfMBChar++;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   if (mState == eDetecting)
michael@0:     if (GetConfidence() > SHORTCUT_THRESHOLD)
michael@0:       mState = eFoundIt;
michael@0:   return mState;
michael@0: }
michael@0: 
michael@0: #define ONE_CHAR_PROB   (float)0.50
michael@0: 
michael@0: float nsUTF8Prober::GetConfidence(void)
michael@0: {
michael@0:   float unlike = (float)0.99;
michael@0: 
michael@0:   if (mNumOfMBChar < 6)
michael@0:   {
michael@0:     for (uint32_t i = 0; i < mNumOfMBChar; i++)
michael@0:       unlike *= ONE_CHAR_PROB;
michael@0:     return (float)1.0 - unlike;
michael@0:   }
michael@0:   else
michael@0:     return (float)0.99;
michael@0: }
michael@0: