File Coverage

src/nsLatin1Prober.cpp

Criterion	Covered	Total	%
statement	30	33	90.9
branch	14	20	70.0
condition			n/a
subroutine			n/a
pod			n/a
total	44	53	83.0

/* -*- 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 <[e-mail]>
  *
  * 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 "nsLatin1Prober.h"
#include "prmem.h"
#include <stdio.h>

#define UDF    0        // undefined
#define OTH    1        //other
#define ASC    2        // ascii capital letter
#define ASS    3        // ascii small letter
#define ACV    4        // accent capital vowel
#define ACO    5        // accent capital other
#define ASV    6        // accent small vowel
#define ASO    7        // accent small other
#define CLASS_NUM   8    // total classes

static unsigned char Latin1_CharToClass[] =
{
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   // 00 - 07
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   // 08 - 0F
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   // 10 - 17
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   // 18 - 1F
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   // 20 - 27
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   // 28 - 2F
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   // 30 - 37
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   // 38 - 3F
  OTH, ASC, ASC, ASC, ASC, ASC, ASC, ASC,   // 40 - 47
  ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,   // 48 - 4F
  ASC, ASC, ASC, ASC, ASC, ASC, ASC, ASC,   // 50 - 57
  ASC, ASC, ASC, OTH, OTH, OTH, OTH, OTH,   // 58 - 5F
  OTH, ASS, ASS, ASS, ASS, ASS, ASS, ASS,   // 60 - 67
  ASS, ASS, ASS, ASS, ASS, ASS, ASS, ASS,   // 68 - 6F
  ASS, ASS, ASS, ASS, ASS, ASS, ASS, ASS,   // 70 - 77
  ASS, ASS, ASS, OTH, OTH, OTH, OTH, OTH,   // 78 - 7F
  OTH, UDF, OTH, ASO, OTH, OTH, OTH, OTH,   // 80 - 87
  OTH, OTH, ACO, OTH, ACO, UDF, ACO, UDF,   // 88 - 8F
  UDF, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   // 90 - 97
  OTH, OTH, ASO, OTH, ASO, UDF, ASO, ACO,   // 98 - 9F
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   // A0 - A7
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   // A8 - AF
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   // B0 - B7
  OTH, OTH, OTH, OTH, OTH, OTH, OTH, OTH,   // B8 - BF
  ACV, ACV, ACV, ACV, ACV, ACV, ACO, ACO,   // C0 - C7
  ACV, ACV, ACV, ACV, ACV, ACV, ACV, ACV,   // C8 - CF
  ACO, ACO, ACV, ACV, ACV, ACV, ACV, OTH,   // D0 - D7
  ACV, ACV, ACV, ACV, ACV, ACO, ACO, ACO,   // D8 - DF
  ASV, ASV, ASV, ASV, ASV, ASV, ASO, ASO,   // E0 - E7
  ASV, ASV, ASV, ASV, ASV, ASV, ASV, ASV,   // E8 - EF
  ASO, ASO, ASV, ASV, ASV, ASV, ASV, OTH,   // F0 - F7
  ASV, ASV, ASV, ASV, ASV, ASO, ASO, ASO,   // F8 - FF
};


/* 0 : illegal
      1 : very unlikely
      2 : normal
      3 : very likely
*/
static unsigned char Latin1ClassModel[] =
{
/*      UDF OTH ASC ASS ACV ACO ASV ASO  */
/*UDF*/  0,  0,  0,  0,  0,  0,  0,  0,
/*OTH*/  0,  3,  3,  3,  3,  3,  3,  3,
/*ASC*/  0,  3,  3,  3,  3,  3,  3,  3,
/*ASS*/  0,  3,  3,  3,  1,  1,  3,  3,
/*ACV*/  0,  3,  3,  3,  1,  2,  1,  2,
/*ACO*/  0,  3,  3,  3,  3,  3,  3,  3,
/*ASV*/  0,  3,  1,  3,  1,  1,  1,  3,
/*ASO*/  0,  3,  1,  3,  1,  1,  3,  3,
};

void  nsLatin1Prober::Reset(void)
{
    mState = eDetecting;
    mLastCharClass = OTH;
    for (int i = 0; i < FREQ_CAT_NUM; i++)
        mFreqCounter[i] = 0;
}


nsProbingState nsLatin1Prober::HandleData(const char* aBuf, PRUint32 aLen)
{
    char *newBuf1 = 0;
    PRUint32 newLen1 = 0;

    if (!FilterWithEnglishLetters(aBuf, aLen, &newBuf1, newLen1)) {
        newBuf1 = (char*)aBuf;
        newLen1 = aLen;
    }

    unsigned char charClass;
    unsigned char freq;
    for (PRUint32 i = 0; i < newLen1; i++)
    {
        charClass = Latin1_CharToClass[(unsigned char)newBuf1[i]];
        freq = Latin1ClassModel[mLastCharClass*CLASS_NUM + charClass];
        if (freq == 0) {
            mState = eNotMe;
            break;
        }
        mFreqCounter[freq]++;
        mLastCharClass = charClass;
    }

    if (newBuf1 != aBuf)
        PR_FREEIF(newBuf1);

    return mState;
}

float nsLatin1Prober::GetConfidence(void)
{
    if (mState == eNotMe)
        return 0.01f;

    float confidence;
    PRUint32 total = 0;
    for (PRInt32 i = 0; i < FREQ_CAT_NUM; i++)
        total += mFreqCounter[i];

    if(!total)
        confidence = 0.0f;
    else
    {
        confidence = mFreqCounter[3]*1.0f / total;
    confidence -= mFreqCounter[1]*20.0f/total;
  }

  if (confidence < 0.0f)
    confidence = 0.0f;

  // lower the confidence of latin1 so that other more accurate detector
  // can take priority.
  confidence *= 0.50f;

  return confidence;
}

#ifdef DEBUG_chardet
void  nsLatin1Prober::DumpStatus()
{
  printf(" Latin1Prober: %1.3f [%s]\r\n", GetConfidence(), GetCharSetName());
}
#endif