latin1prober.js
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/*
* 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):
* António Afonso (antonio.afonso gmail.com) - port to JavaScript
* Mark Pilgrim - port to Python
* Shy Shalom - original C code
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
!function(jschardet) {
(function() {
var UDF = 0; // undefined
var OTH = 1; // other
jschardet.OTH = 1;
var ASC = 2; // ascii capital letter
var ASS = 3; // ascii small letter
var ACV = 4; // accent capital vowel
var ACO = 5; // accent capital other
var ASV = 6; // accent small vowel
var ASO = 7; // accent small other
jschardet.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
jschardet.Latin1ClassModel = [
// UDF OTH ASC ASS ACV ACO ASV ASO
0, 0, 0, 0, 0, 0, 0, 0, // UDF
0, 3, 3, 3, 3, 3, 3, 3, // OTH
0, 3, 3, 3, 3, 3, 3, 3, // ASC
0, 3, 3, 3, 1, 1, 3, 3, // ASS
0, 3, 3, 3, 1, 2, 1, 2, // ACV
0, 3, 3, 3, 3, 3, 3, 3, // ACO
0, 3, 1, 3, 1, 1, 1, 3, // ASV
0, 3, 1, 3, 1, 1, 3, 3 // ASO
];
})();
jschardet.Latin1Prober = function() {
jschardet.CharSetProber.apply(this);
var FREQ_CAT_NUM = 4;
var CLASS_NUM = 8; // total classes
var self = this;
function init() {
self.reset();
}
this.reset = function() {
this._mLastCharClass = jschardet.OTH;
this._mFreqCounter = [];
for( var i = 0; i < FREQ_CAT_NUM; this._mFreqCounter[i++] = 0 );
jschardet.Latin1Prober.prototype.reset.apply(this);
}
this.getCharsetName = function() {
return "windows-1252";
}
this.feed = function(aBuf) {
aBuf = this.filterWithEnglishLetters(aBuf);
for( var i = 0; i < aBuf.length; i++ ) {
var c = aBuf.charCodeAt(i);
var charClass = jschardet.Latin1_CharToClass[c];
var freq = jschardet.Latin1ClassModel[(this._mLastCharClass * CLASS_NUM) + charClass];
if( freq == 0 ) {
this._mState = jschardet.Constants.notMe;
break;
}
this._mFreqCounter[freq]++;
this._mLastCharClass = charClass;
}
return this.getState();
}
this.getConfidence = function() {
var confidence;
var constants;
if( this.getState() == jschardet.Constants.notMe ) {
return 0.01;
}
var total = 0;
for( var i = 0; i < this._mFreqCounter.length; i++ ) {
total += this._mFreqCounter[i];
}
if( total < 0.01 ) {
constants = 0.0;
} else {
confidence = (this._mFreqCounter[3] / total) - (this._mFreqCounter[1] * 20 / total);
}
if( confidence < 0 ) {
confidence = 0.0;
}
// lower the confidence of latin1 so that other more accurate detector
// can take priority.
//
// antonio.afonso: need to change this otherwise languages like pt, es, fr using latin1 will never be detected.
confidence = confidence * 0.95;
return confidence;
}
init();
}
jschardet.Latin1Prober.prototype = new jschardet.CharSetProber();
}(require('./init'));