/*******************************************************************************
* Copyright (c) 2001, 2012 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
* Jens Lukowski/Innoopract - initial renaming/restructuring
*
*******************************************************************************/
package org.eclipse.wst.html.core.internal.contenttype;
/**
*
* This is ported from PageDesigner's hpbcom/Kanji.cpp's
* Kanji::guess_kanji_code(),
*
*/
public class EncodingGuesser {
private static final int ASCII = 0; // ASCII
// ISO-2022-JP
private static final int ASCII_IN = 8; // This is after ISO2022's change
// Shift-JIS
private static final int EUC_HALFKANA = 6; // This is Half Kana in EUC-JP
private static final int EUC_JP = 3; // This is EUC-JP
private static final int ISO2022_JP = 4; // This is ISO-2022-JP
private static final int JIS_HALFKANA = 7; // THis is Half Kana in
private static final byte KT_EUC1 = 0x40;
private static final byte KT_EUC2 = (byte) 0x80;
// ASCII
private static final byte KT_JIN = 0x01;
private static final byte KT_JOUT = 0x02;
// private static final byte KT_ESC = 0x04;
// private static final byte KT_JIS = 0x08;
private static final byte KT_SFT1 = 0x10;
private static final byte KT_SFT2 = 0x20;
private static final byte ktype[] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 00 */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 10 */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08, 0x08, 0x08, 0x09, 0x08, 0x08, 0x08, /* !"#$%&' *//* " */
0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, /* ()*+,-./ */
0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, /* 01234567 */
0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, /* 89:; <=>? */
0x29, 0x28, 0x2b, 0x28, 0x28, 0x28, 0x28, 0x28, /* @ABCDEFG */
0x2a, 0x28, 0x2a, 0x28, 0x28, 0x28, 0x28, 0x28, /* HIJKLMNO */
0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, /* PQRSTUVW */
0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, /* XYZ[\]^_ */
0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, /* abcdefg */
0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, /* hijklmno */
0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, /* pqrstuvw */
0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x28, 0x00, /* xyz{|}~ */
0x20, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, /* 80 */
0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, /* 90 */
0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x20, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, /* A0 */
(byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, /* B0 */
(byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, /* C0 */
(byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, /* D0 */
(byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xe0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, /* E0 */
(byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, /* F0 */
(byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xf0, (byte) 0xc0, (byte) 0xc0, 0x00,};
// private static final int ISO8859_1 = 1; // ISO-1
private static final int SHIFT_JIS = 2; // This is Shift-JIS
private static final int SJIS_HALFKANA = 5; // This is Half Kana in
/**
* Currently, only Japanese encodings are supported.
*/
private static final int UNKNOWN = -1; // Unknown
private static final boolean IS_GUESSING_ENABLED = isGuessingEnabled();
/**
* @return java.lang.String
* @param code
* int
*
* Convert private int to IANA Encoding name.
*/
private static String convertToIANAEncodingName(int code) {
String encoding = null;
switch (code) {
case SHIFT_JIS :
case SJIS_HALFKANA :
encoding = "Shift_JIS";//$NON-NLS-1$
break;
case EUC_JP :
case EUC_HALFKANA :
encoding = "EUC-JP";//$NON-NLS-1$
break;
case ISO2022_JP :
case JIS_HALFKANA :
encoding = "ISO-2022-JP";//$NON-NLS-1$
default :
break;
}
return encoding;
}
public static boolean canGuess() {
if (!IS_GUESSING_ENABLED) {
return false;
}
// Currently, only Japanese is supported.
String system_ctype = java.util.Locale.getDefault().getLanguage();
String jp_ctype = java.util.Locale.JAPANESE.getLanguage();
return system_ctype.compareTo(jp_ctype) == 0;
}
private static boolean isGuessingEnabled() {
String value = System.getProperty("org.eclipse.wst.html.encoding.guess");
return value == null || Boolean.valueOf(value).booleanValue();
}
/**
* Return guessed Java Encoding name target: bytes to be inspected length:
* length of target
*/
public static String guessEncoding(byte[] target, int length) {
int code = UNKNOWN;
if (canGuess()) {
// Ok, I'm under ja_JP.
code = ASCII;
int pos = 0;
while ((code == ASCII) && (length > 0)) {
int ch1 = target[pos];
ch1 = ch1 & 0x000000FF;
int ch2 = (length >= 2) ? target[pos + 1] : 0;
ch2 = ch2 & 0x000000FF;
int ch3 = (length >= 3) ? target[pos + 2] : 0;
ch3 = ch3 & 0x000000FF;
code = guessJapaneseKanjiCode(ch1, ch2, ch3, 0);
pos++;
length--;
}
switch (code) {
case ISO2022_JP :
case JIS_HALFKANA :
code = ISO2022_JP;
break;
case EUC_JP :
code = EUC_JP;
break;
case SHIFT_JIS :
case SJIS_HALFKANA :
code = SHIFT_JIS;
break;
default :
return null;
}
}
return (convertToIANAEncodingName(code));
}
/**
* Guess the encoding. halfkana_flag = 0x01 ( detect SJIS half kana )
* halfkana_flag = 0x02 ( detect EUC half kana )
*/
private static int guessJapaneseKanjiCode(int ch1, int ch2, int ch3, int halfkana_flag) {
boolean sjis_hankaku_flag = ((halfkana_flag & 0x01) != 0) ? true : false;
boolean euc_hankaku_flag = ((halfkana_flag & 0x02) != 0) ? true : false;
if (ch1 == 0)
return UNKNOWN;
if (sjis_hankaku_flag && ch1 >= 0xa1 && ch1 <= 0xdf)
return SJIS_HALFKANA;
else if (euc_hankaku_flag && ch1 == 0x8e && ch2 >= 0xa1 && ch2 <= 0xdf)
return EUC_HALFKANA;
else if (((ktype[ch1] & KT_SFT1) != 0) && ((ktype[ch2] & KT_SFT2) != 0))
return SHIFT_JIS;
else if (((ktype[ch1] & KT_EUC1) != 0) && ((ktype[ch2] & KT_EUC2) != 0))
return EUC_JP;
else if (ch1 == 0x1b && ((ktype[ch2] & KT_JIN) != 0))
return ISO2022_JP;
else if (ch1 >= 0xa1 && ch1 <= 0xdf)
return SJIS_HALFKANA;
else if (ch1 == 0x1b && ch2 == 0x28/* '(' */&& ch3 == 0x49/* 'I' */)
return JIS_HALFKANA;
else if (ch1 == 0x1b && ch2 == 0x28/* '(' */&& ((ktype[ch3] & KT_JOUT) != 0))
return ASCII_IN;
return ASCII;
}
public EncodingGuesser() {
super();
}
}