/* -*- 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 "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 const 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 const 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