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/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#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, uint32_t aLen)
{
char *newBuf1 = 0;
uint32_t newLen1 = 0;
if (!FilterWithEnglishLetters(aBuf, aLen, &newBuf1, newLen1)) {
newBuf1 = (char*)aBuf;
newLen1 = aLen;
}
unsigned char charClass;
unsigned char freq;
for (uint32_t 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;
uint32_t total = 0;
for (int32_t 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
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