RetroZilla/extensions/universalchardet/src/nsSBCharSetProber.cpp
2015-10-20 23:03:22 -04:00

127 lines
3.9 KiB
C++

/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Universal charset detector code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 2001
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Shy Shalom <shooshX@gmail.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include <stdio.h>
#include "nsSBCharSetProber.h"
nsProbingState nsSingleByteCharSetProber::HandleData(const char* aBuf, PRUint32 aLen)
{
unsigned char order;
for (PRUint32 i = 0; i < aLen; i++)
{
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[mModel->precedenceMatrix[mLastOrder*SAMPLE_SIZE+order]]);
else // reverse the order of the letters in the lookup
++(mSeqCounters[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 (PRUint32 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_chardet
void nsSingleByteCharSetProber::DumpStatus()
{
printf(" SBCS: %1.3f [%s]\r\n", GetConfidence(), GetCharSetName());
}
#endif