/* ***** 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.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Kohei TAKETA <k-tak@void.in> (Java port)
*
* 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 ***** */
package org.mozilla.universalchardet.prober;
import org.mozilla.universalchardet.prober.statemachine.CodingStateMachine;
import org.mozilla.universalchardet.prober.statemachine.SMModel;
import org.mozilla.universalchardet.prober.statemachine.UTF8SMModel;
import org.mozilla.universalchardet.Constants;
public class UTF8Prober extends CharsetProber
{
////////////////////////////////////////////////////////////////
// constants
////////////////////////////////////////////////////////////////
public static final float ONE_CHAR_PROB = 0.50f;
////////////////////////////////////////////////////////////////
// fields
////////////////////////////////////////////////////////////////
private CodingStateMachine codingSM;
private ProbingState state;
private int numOfMBChar;
private static final SMModel smModel = new UTF8SMModel();
////////////////////////////////////////////////////////////////
// methods
////////////////////////////////////////////////////////////////
public UTF8Prober()
{
super();
this.numOfMBChar = 0;
this.codingSM = new CodingStateMachine(smModel);
reset();
}
public String getCharSetName()
{
return Constants.CHARSET_UTF_8;
}
public ProbingState handleData(final byte[] buf, int offset, int length)
{
int codingState;
int maxPos = offset + length;
for (int i=offset; i<maxPos; ++i) {
codingState = this.codingSM.nextState(buf[i]);
if (codingState == SMModel.ERROR) {
this.state = ProbingState.NOT_ME;
break;
}
if (codingState == SMModel.ITSME) {
this.state = ProbingState.FOUND_IT;
break;
}
if (codingState == SMModel.START) {
if (this.codingSM.getCurrentCharLen() >= 2) {
++this.numOfMBChar;
}
}
}
if (this.state == ProbingState.DETECTING) {
if (getConfidence() > SHORTCUT_THRESHOLD) {
this.state = ProbingState.FOUND_IT;
}
}
return this.state;
}
public ProbingState getState()
{
return this.state;
}
public void reset()
{
this.codingSM.reset();
this.numOfMBChar = 0;
this.state = ProbingState.DETECTING;
}
public float getConfidence()
{
float unlike = 0.99f;
if (this.numOfMBChar < 6) {
for (int i=0; i<this.numOfMBChar; ++i) {
unlike *= ONE_CHAR_PROB;
}
return (1.0f - unlike);
} else {
return 0.99f;
}
}
public void setOption()
{}
}