Line data    Source code

       1             : /* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2             : /* This Source Code Form is subject to the terms of the Mozilla Public
       3             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       4             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       5             : 
       6             : #include "nsUTF8Prober.h"
       7             : 
       8           0 : void  nsUTF8Prober::Reset(void)
       9             : {
      10           0 :   mCodingSM->Reset();
      11           0 :   mNumOfMBChar = 0;
      12           0 :   mState = eDetecting;
      13           0 : }
      14             : 
      15           0 : nsProbingState nsUTF8Prober::HandleData(const char* aBuf, uint32_t aLen)
      16             : {
      17             :   nsSMState codingState;
      18             : 
      19           0 :   for (uint32_t i = 0; i < aLen; i++)
      20             :   {
      21           0 :     codingState = mCodingSM->NextState(aBuf[i]);
      22           0 :     if (codingState == eItsMe)
      23             :     {
      24           0 :       mState = eFoundIt;
      25           0 :       break;
      26             :     }
      27           0 :     if (codingState == eStart)
      28             :     {
      29           0 :       if (mCodingSM->GetCurrentCharLen() >= 2)
      30           0 :         mNumOfMBChar++;
      31             :     }
      32             :   }
      33             : 
      34           0 :   if (mState == eDetecting)
      35           0 :     if (GetConfidence() > SHORTCUT_THRESHOLD)
      36           0 :       mState = eFoundIt;
      37           0 :   return mState;
      38             : }
      39             : 
      40             : #define ONE_CHAR_PROB   (float)0.50
      41             : 
      42           0 : float nsUTF8Prober::GetConfidence(void)
      43             : {
      44           0 :   float unlike = (float)0.99;
      45             : 
      46           0 :   if (mNumOfMBChar < 6)
      47             :   {
      48           0 :     for (uint32_t i = 0; i < mNumOfMBChar; i++)
      49           0 :       unlike *= ONE_CHAR_PROB;
      50           0 :     return (float)1.0 - unlike;
      51             :   }
      52             :   else
      53           0 :     return (float)0.99;
      54             : }
      55             :