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: #include <stdio.h>
michael@0: #include "nsSBCharSetProber.h"
michael@0: 
michael@0: nsProbingState nsSingleByteCharSetProber::HandleData(const char* aBuf, uint32_t aLen)
michael@0: {
michael@0:   unsigned char order;
michael@0: 
michael@0:   for (uint32_t i = 0; i < aLen; i++)
michael@0:   {
michael@0:     order = mModel->charToOrderMap[(unsigned char)aBuf[i]];
michael@0: 
michael@0:     if (order < SYMBOL_CAT_ORDER)
michael@0:       mTotalChar++;
michael@0:     if (order < SAMPLE_SIZE)
michael@0:     {
michael@0:         mFreqChar++;
michael@0: 
michael@0:       if (mLastOrder < SAMPLE_SIZE)
michael@0:       {
michael@0:         mTotalSeqs++;
michael@0:         if (!mReversed)
michael@0:           ++(mSeqCounters[mModel->precedenceMatrix[mLastOrder*SAMPLE_SIZE+order]]);
michael@0:         else // reverse the order of the letters in the lookup
michael@0:           ++(mSeqCounters[mModel->precedenceMatrix[order*SAMPLE_SIZE+mLastOrder]]);
michael@0:       }
michael@0:     }
michael@0:     mLastOrder = order;
michael@0:   }
michael@0: 
michael@0:   if (mState == eDetecting)
michael@0:     if (mTotalSeqs > SB_ENOUGH_REL_THRESHOLD)
michael@0:     {
michael@0:       float cf = GetConfidence();
michael@0:       if (cf > POSITIVE_SHORTCUT_THRESHOLD)
michael@0:         mState = eFoundIt;
michael@0:       else if (cf < NEGATIVE_SHORTCUT_THRESHOLD)
michael@0:         mState = eNotMe;
michael@0:     }
michael@0: 
michael@0:   return mState;
michael@0: }
michael@0: 
michael@0: void  nsSingleByteCharSetProber::Reset(void)
michael@0: {
michael@0:   mState = eDetecting;
michael@0:   mLastOrder = 255;
michael@0:   for (uint32_t i = 0; i < NUMBER_OF_SEQ_CAT; i++)
michael@0:     mSeqCounters[i] = 0;
michael@0:   mTotalSeqs = 0;
michael@0:   mTotalChar = 0;
michael@0:   mFreqChar = 0;
michael@0: }
michael@0: 
michael@0: //#define NEGATIVE_APPROACH 1
michael@0: 
michael@0: float nsSingleByteCharSetProber::GetConfidence(void)
michael@0: {
michael@0: #ifdef NEGATIVE_APPROACH
michael@0:   if (mTotalSeqs > 0)
michael@0:     if (mTotalSeqs > mSeqCounters[NEGATIVE_CAT]*10 )
michael@0:       return ((float)(mTotalSeqs - mSeqCounters[NEGATIVE_CAT]*10))/mTotalSeqs * mFreqChar / mTotalChar;
michael@0:   return (float)0.01;
michael@0: #else  //POSITIVE_APPROACH
michael@0:   float r;
michael@0: 
michael@0:   if (mTotalSeqs > 0) {
michael@0:     r = ((float)1.0) * mSeqCounters[POSITIVE_CAT] / mTotalSeqs / mModel->mTypicalPositiveRatio;
michael@0:     r = r*mFreqChar/mTotalChar;
michael@0:     if (r >= (float)1.00)
michael@0:       r = (float)0.99;
michael@0:     return r;
michael@0:   }
michael@0:   return (float)0.01;
michael@0: #endif
michael@0: }
michael@0: 
michael@0: const char* nsSingleByteCharSetProber::GetCharSetName() 
michael@0: {
michael@0:   if (!mNameProber)
michael@0:     return mModel->charsetName;
michael@0:   return mNameProber->GetCharSetName();
michael@0: }
michael@0: 
michael@0: #ifdef DEBUG_chardet
michael@0: void nsSingleByteCharSetProber::DumpStatus()
michael@0: {
michael@0:   printf("  SBCS: %1.3f [%s]\r\n", GetConfidence(), GetCharSetName());
michael@0: }
michael@0: #endif