File indexing completed on 2024-04-28 03:53:04

 /*  -*- C++ -*-
     SPDX-FileCopyrightText: 1998 Netscape Communications Corporation <developer@mozilla.org>
 
     SPDX-License-Identifier: MIT
 */
 
 #include "nsSBCharSetProber.h"
 
 #include <stdio.h>
 
 namespace kencodingprober
 {
 nsProbingState nsSingleByteCharSetProber::HandleData(const char *aBuf, unsigned int aLen)
 {
     for (unsigned int i = 0; i < aLen; i++) {
         const unsigned char order = mModel->charToOrderMap[(unsigned char)aBuf[i]];
 
         if (order < SYMBOL_CAT_ORDER) {
             mTotalChar++;
         }
         if (order < SAMPLE_SIZE) {
             mFreqChar++;
 
             if (mLastOrder < SAMPLE_SIZE) {
                 mTotalSeqs++;
                 if (!mReversed) {
                     ++(mSeqCounters[(int)mModel->precedenceMatrix[mLastOrder * SAMPLE_SIZE + order]]);
                 } else { // reverse the order of the letters in the lookup
                     ++(mSeqCounters[(int)mModel->precedenceMatrix[order * SAMPLE_SIZE + mLastOrder]]);
                 }
             }
         }
         mLastOrder = order;
     }
 
     if (mState == eDetecting) {
         if (mTotalSeqs > SB_ENOUGH_REL_THRESHOLD) {
             float cf = GetConfidence();
             if (cf > POSITIVE_SHORTCUT_THRESHOLD) {
                 mState = eFoundIt;
             } else if (cf < NEGATIVE_SHORTCUT_THRESHOLD) {
                 mState = eNotMe;
             }
         }
     }
 
     return mState;
 }
 
 void nsSingleByteCharSetProber::Reset(void)
 {
     mState = eDetecting;
     mLastOrder = 255;
     for (unsigned int i = 0; i < NUMBER_OF_SEQ_CAT; i++) {
         mSeqCounters[i] = 0;
     }
     mTotalSeqs = 0;
     mTotalChar = 0;
     mFreqChar = 0;
 }
 
 //#define NEGATIVE_APPROACH 1
 
 float nsSingleByteCharSetProber::GetConfidence(void)
 {
 #ifdef NEGATIVE_APPROACH
     if (mTotalSeqs > 0)
         if (mTotalSeqs > mSeqCounters[NEGATIVE_CAT] * 10) {
             return ((float)(mTotalSeqs - mSeqCounters[NEGATIVE_CAT] * 10)) / mTotalSeqs * mFreqChar / mTotalChar;
         }
     return (float)0.01;
 #else // POSITIVE_APPROACH
     float r;
 
     if (mTotalSeqs > 0) {
         r = ((float)1.0) * mSeqCounters[POSITIVE_CAT] / mTotalSeqs / mModel->mTypicalPositiveRatio;
         r = r * mFreqChar / mTotalChar;
         if (r >= (float)1.00) {
             r = (float)0.99;
         }
         return r;
     }
     return (float)0.01;
 #endif
 }
 
 const char *nsSingleByteCharSetProber::GetCharSetName()
 {
     if (!mNameProber) {
         return mModel->charsetName;
     }
     return mNameProber->GetCharSetName();
 }
 
 #ifdef DEBUG_PROBE
 void nsSingleByteCharSetProber::DumpStatus()
 {
     printf("  SBCS: %1.3f [%s]\r\n", GetConfidence(), GetCharSetName());
 }
 #endif
 }