org.mozilla.universalchardet.UniversalDetector Maven / Gradle / Ivy
/*
(C) Copyright 2016-2017 Alberto Fernández
(C) Copyright 2006-2007 Kohei TAKETA (Java port)
(C) Copyright 2001 Netscape Communications Corporation.
* 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
* Kohei TAKETA (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.
*
*
*/
package org.mozilla.universalchardet;
import static org.mozilla.universalchardet.Constants.CHARSET_US_ASCCI;
import static org.mozilla.universalchardet.Constants.CHARSET_UTF_16BE;
import static org.mozilla.universalchardet.Constants.CHARSET_UTF_16LE;
import static org.mozilla.universalchardet.Constants.CHARSET_UTF_32BE;
import static org.mozilla.universalchardet.Constants.CHARSET_UTF_32LE;
import static org.mozilla.universalchardet.Constants.CHARSET_UTF_8;
import static org.mozilla.universalchardet.Constants.CHARSET_X_ISO_10646_UCS_4_2143;
import static org.mozilla.universalchardet.Constants.CHARSET_X_ISO_10646_UCS_4_3412;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import org.mozilla.universalchardet.prober.CharsetProber;
import org.mozilla.universalchardet.prober.EscCharsetProber;
import org.mozilla.universalchardet.prober.Latin1Prober;
import org.mozilla.universalchardet.prober.MBCSGroupProber;
import org.mozilla.universalchardet.prober.SBCSGroupProber;
public class UniversalDetector {
////////////////////////////////////////////////////////////////
// constants
////////////////////////////////////////////////////////////////
public static final float SHORTCUT_THRESHOLD = 0.95f;
public static final float MINIMUM_THRESHOLD = 0.20f;
////////////////////////////////////////////////////////////////
// inner types
////////////////////////////////////////////////////////////////
public enum InputState {
PURE_ASCII, ESC_ASCII, HIGHBYTE
}
////////////////////////////////////////////////////////////////
// fields
////////////////////////////////////////////////////////////////
private InputState inputState;
private boolean done;
private boolean start;
private boolean gotData;
private boolean onlyPrintableASCII = true;
private byte lastChar;
private String detectedCharset;
private CharsetProber[] probers;
private CharsetProber escCharsetProber;
private CharsetListener listener;
////////////////////////////////////////////////////////////////
// methods
////////////////////////////////////////////////////////////////
public UniversalDetector() {
this(null);
}
/**
* @param listener a listener object that is notified of
* the detected encocoding. Can be null.
*/
public UniversalDetector(CharsetListener listener) {
this.listener = listener;
this.escCharsetProber = null;
this.probers = new CharsetProber[3];
reset();
}
public boolean isDone() {
return this.done;
}
/**
* @return The detected encoding is returned. If the detector couldn't
* determine what encoding was used, null is returned.
*/
public String getDetectedCharset() {
return this.detectedCharset;
}
public void setListener(CharsetListener listener) {
this.listener = listener;
}
public CharsetListener getListener() {
return this.listener;
}
/**
* Feed the detector with more data
* @param buf The buffer containing the data
*/
public void handleData(final byte[] buf) {
handleData(buf, 0, buf.length);
}
/**
* Feed the detector with more data
* @param buf Buffer with the data
* @param offset initial position of data in buf
* @param length length of data
*/
public void handleData(final byte[] buf, int offset, int length) {
if (this.done) {
return;
}
if (length > 0) {
this.gotData = true;
}
if (this.start) {
this.start = false;
if (length > 3) {
String detectedBOM = detectCharsetFromBOM(buf, offset);
if (detectedBOM != null) {
this.detectedCharset = detectedBOM;
this.done = true;
return;
}
}
} // if (start) end
int maxPos = offset + length;
for (int i=offset; i= 0x20 && c <= 0x7e) // Printable characters
|| c == 0x0A // New Line
|| c == 0x0D // Carriage return
|| c== 0x09; // TAB
}
this.lastChar = buf[i];
}
} // for end
CharsetProber.ProbingState st;
if (this.inputState == InputState.ESC_ASCII) {
if (this.escCharsetProber == null) {
this.escCharsetProber = new EscCharsetProber();
}
st = this.escCharsetProber.handleData(buf, offset, length);
if (st == CharsetProber.ProbingState.FOUND_IT) {
this.done = true;
this.detectedCharset = this.escCharsetProber.getCharSetName();
}
} else if (this.inputState == InputState.HIGHBYTE) {
for (int i=0; i (offset + 3)) {
int b1 = buf[offset] & 0xFF;
int b2 = buf[offset+1] & 0xFF;
int b3 = buf[offset+2] & 0xFF;
int b4 = buf[offset+3] & 0xFF;
switch (b1) {
case 0xEF:
if (b2 == 0xBB && b3 == 0xBF) {
return CHARSET_UTF_8;
}
break;
case 0xFE:
if (b2 == 0xFF && b3 == 0x00 && b4 == 0x00) {
return CHARSET_X_ISO_10646_UCS_4_3412;
} else if (b2 == 0xFF) {
return CHARSET_UTF_16BE;
}
break;
case 0x00:
if (b2 == 0x00 && b3 == 0xFE && b4 == 0xFF) {
return CHARSET_UTF_32BE;
} else if (b2 == 0x00 && b3 == 0xFF && b4 == 0xFE) {
return CHARSET_X_ISO_10646_UCS_4_2143;
}
break;
case 0xFF:
if (b2 == 0xFE && b3 == 0x00 && b4 == 0x00) {
return CHARSET_UTF_32LE;
} else if (b2 == 0xFE) {
return CHARSET_UTF_16LE;
}
break;
default:
break;
} // swich end
}
return null;
}
/**
* Marks end of data reading. Finish calculations.
*/
public void dataEnd() {
if (!this.gotData) {
return;
}
if (this.detectedCharset != null) {
this.done = true;
if (this.listener != null) {
this.listener.report(this.detectedCharset);
}
return;
}
if (this.inputState == InputState.HIGHBYTE) {
float proberConfidence;
float maxProberConfidence = 0.0f;
int maxProber = 0;
for (int i=0; i maxProberConfidence) {
maxProberConfidence = proberConfidence;
maxProber = i;
}
}
if (maxProberConfidence > MINIMUM_THRESHOLD) {
this.detectedCharset = this.probers[maxProber].getCharSetName();
if (this.listener != null) {
this.listener.report(this.detectedCharset);
}
}
} else if (this.inputState == InputState.ESC_ASCII) {
// do nothing
} else if (this.inputState == InputState.PURE_ASCII && this.onlyPrintableASCII) {
this.detectedCharset = CHARSET_US_ASCCI;
}
else {
// do nothing
}
}
/**
* Resets detector to be used again.
*/
public final void reset() {
this.done = false;
this.start = true;
this.detectedCharset = null;
this.gotData = false;
this.inputState = InputState.PURE_ASCII;
this.lastChar = 0;
if (this.escCharsetProber != null) {
this.escCharsetProber.reset();
}
for (int i=0; i 0 && !detector.isDone()) {
detector.handleData(buf, 0, nread);
}
detector.dataEnd();
String encoding = detector.getDetectedCharset();
detector.reset();
return encoding;
}
}
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