utf8prober.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) {
jschardet.UTF8Prober = function() {
jschardet.CharSetProber.apply(this);
var ONE_CHAR_PROB = 0.5;
var self = this;
function init() {
self._mCodingSM = new jschardet.CodingStateMachine(jschardet.UTF8SMModel);
self.reset();
}
this.reset = function() {
jschardet.UTF8Prober.prototype.reset.apply(this);
this._mCodingSM.reset();
this._mNumOfMBChar = 0;
}
this.getCharsetName = function() {
return "UTF-8";
}
this.feed = function(aBuf) {
for( var i = 0, c; i < aBuf.length; i++ ) {
c = aBuf[i];
var codingState = this._mCodingSM.nextState(c);
if( codingState == jschardet.Constants.error ) {
this._mState = jschardet.Constants.notMe;
break;
} else if( codingState == jschardet.Constants.itsMe ) {
this._mState = jschardet.Constants.foundIt;
break;
} else if( codingState == jschardet.Constants.start ) {
if( this._mCodingSM.getCurrentCharLen() >= 2 ) {
this._mNumOfMBChar++;
}
}
}
if( this.getState() == jschardet.Constants.detecting ) {
if( this.getConfidence() > jschardet.Constants.SHORTCUT_THRESHOLD ) {
this._mState = jschardet.Constants.foundIt;
}
}
return this.getState();
}
this.getConfidence = function() {
var unlike = 0.99;
if( this._mNumOfMBChar < 6 ) {
for( var i = 0; i < this._mNumOfMBChar; i++ ) {
unlike *= ONE_CHAR_PROB;
}
return 1 - unlike;
} else {
return unlike;
}
}
init();
}
jschardet.UTF8Prober.prototype = new jschardet.CharSetProber();
}(require('./init'));