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An easy to use Application Programming Interface (API) for working with MARC and MARCXML in Java.
/**
* Copyright (C) 2002 Bas Peters ([email protected])
*
* This file is part of MARC4J
*
* MARC4J 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.
*
* MARC4J 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 MARC4J; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.marc4j.converter.impl;
import java.io.InputStream;
import java.lang.reflect.Constructor;
import java.text.Normalizer;
import org.marc4j.converter.CharConverter;
/**
*
* A utility to convert UCS/Unicode data to MARC-8.
*
*
* The MARC-8 to Unicode mapping used is the version with the March 2005 revisions.
*
*
* @author Bas Peters
* @author Corey Keith
* @author Robert Haschart
*/
public class UnicodeToAnsel extends CharConverter {
protected ReverseCodeTable rct;
static final char ESC = 0x1b;
static final char G0 = 0x28;
static final char G0multibyte = 0x24;
static final char G1 = 0x29;
static final int ASCII = 0x42;
boolean dontChangeCharset = false;
/**
* Creates a new instance and loads the MARC4J supplied Ansel/Unicode conversion tables based on the official LC
* tables. Loads in the generated class ReverseCodeTableGenerated which contains switch statements to lookup the
* MARC-8 encodings for given Unicode characters.
*/
public UnicodeToAnsel() {
rct = loadGeneratedTable();
// this(UnicodeToAnsel.class
// .getResourceAsStream("resources/codetables.xml"));
}
/**
* Creates a new instance and loads the MARC4J supplied Ansel/Unicode conversion tables based on the official LC
* tables. Loads in the generated class ReverseCodeTableGenerated which contains switch statements to lookup the
* MARC-8 encodings for given Unicode characters.
*
* @param defaultCharsetOnlyPlusNCR - true to enable special mode where no alternate character sets are used
* anything outside the standard base MARC8 lookup table will be written out using a Numeric Code Point
*/
public UnicodeToAnsel(final boolean defaultCharsetOnlyPlusNCR) {
dontChangeCharset = true;
rct = loadGeneratedTable();
// this(UnicodeToAnsel.class
// .getResourceAsStream("resources/codetables.xml"));
}
/**
* Constructs an instance with the specified pathname.
*
* Use this constructor to create an instance with a customized code table
* mapping. The mapping file should follow the structure of LC's XML MARC-8
* to Unicode mapping (see:
* http://www.loc.gov/marc/specifications/codetables.xml).
*
* @param pathname - the name of a file to read to built the ReverseCodeTable instead of the standard LC table
*/
public UnicodeToAnsel(final String pathname) {
rct = new ReverseCodeTableHash(pathname);
}
/**
* Constructs an instance with the specified input stream.
*
* Use this constructor to create an instance with a customized code table
* mapping. The mapping file should follow the structure of LC's XML MARC-8
* to Unicode mapping (see:
* http://www.loc.gov/marc/specifications/codetables.xml).
*
* @param in - an InputStream to read to built the ReverseCodeTable instead of the standard LC table
*/
public UnicodeToAnsel(final InputStream in) {
rct = new ReverseCodeTableHash(in);
}
private ReverseCodeTable loadGeneratedTable() {
try {
final Class generated = Class.forName("org.marc4j.converter.impl.ReverseCodeTableGenerated");
final Constructor cons = generated.getConstructor();
final Object rct = cons.newInstance();
return (ReverseCodeTable) rct;
} catch (final Exception e) {
ReverseCodeTable rct;
rct = new ReverseCodeTableHash(AnselToUnicode.class.getResourceAsStream("resources/codetables.xml"));
return rct;
}
}
/**
* Converts UCS/Unicode data to MARC-8.
*
* If there is no match for a Unicode character, it will be encoded as &#xXXXX; so that if the data is translated
* back into Unicode, the original data can be recreated.
*
*
* @param data - the UCS/Unicode data in an array of char
* @return String - the MARC-8 data
*/
@Override
public String convert(final char data[]) {
final StringBuffer sb = new StringBuffer();
rct.init();
convertPortion(data, sb);
if (rct.getPreviousG0() != ASCII) {
sb.append(ESC);
sb.append(G0);
sb.append((char) ASCII);
}
return sb.toString();
}
/**
* Does the actual work of converting UCS/Unicode data to MARC-8.
*
* If the Unicode data has been normalized into composed form, and the composed character does not have a
* corresponding MARC8 character, this routine will normalize that character into its decomposed form, and try to
* translate that equivalent string into MARC8.
*
*
* @param data - the UCS/Unicode data in an array of char
* @return String - the MARC-8 data
*/
private void convertPortion(final char data[], final StringBuffer sb) {
int prev_len = 1;
for (int i = 0; i < data.length; i++) {
final Character c = new Character(data[i]);
final StringBuffer marc = new StringBuffer();
final int charValue = c.charValue();
if (charValue == 0x20 && rct.getPreviousG0() != '1') {
if (rct.getPreviousG0() == '1') {
sb.append(ESC);
sb.append(G0);
sb.append((char) ASCII);
rct.setPreviousG0(ASCII);
}
marc.append(" ");
} else if (!rct.charHasMatch(c)) {
// Unicode character c has no match in the Marc8 tables. Try unicode-decompose on it
// to see whether the decomposed form can be represented. If when decomposed, all of
// the characters can be translated to marc8, then use that. If not and the decomposed form
// if three (or more) characters long (which indicates multiple diacritic marks), then
// re-compose the the main character with the first diacritic, and check whether that
// and the remaining diacritics can be translated. If so go with that, otherwise, give up
// and merely use the &#xXXXX; Numeric Character Reference form to represent the original
// unicode character
final String tmpnorm = c.toString();
final String tmpNormed = Normalizer.normalize(tmpnorm, Normalizer.Form.NFD);
if (!tmpNormed.equals(tmpnorm)) {
if (allCharsHaveMatch(rct, tmpNormed)) {
convertPortion(tmpNormed.toCharArray(), sb);
continue;
} else if (tmpNormed.length() > 2) {
final String firstTwo = tmpNormed.substring(0, 2);
final String partialNormed = Normalizer.normalize(firstTwo, Normalizer.Form.NFC);
if (!partialNormed.equals(firstTwo) && allCharsHaveMatch(rct, partialNormed) &&
allCharsHaveMatch(rct, tmpNormed.substring(2))) {
convertPortion((partialNormed + tmpNormed.substring(2)).toCharArray(), sb);
continue;
}
}
}
if (rct.getPreviousG0() != ASCII) {
sb.append(ESC);
sb.append(G0);
sb.append((char) ASCII);
rct.setPreviousG0(ASCII);
}
if (charValue < 0x1000) {
marc.append("&#x" + Integer.toHexString(charValue + 0x10000).toUpperCase().substring(1) + ";");
} else {
marc.append("&#x" + Integer.toHexString(charValue).toUpperCase() + ";");
// continue;
}
} else if (rct.inPreviousG0CharEntry(c)) {
marc.append(rct.getCurrentG0CharEntry(c));
} else if (rct.inPreviousG1CharEntry(c)) {
marc.append(rct.getCurrentG1CharEntry(c));
} else if (dontChangeCharset) {
if (charValue < 0x1000) {
marc.append("&#x" + Integer.toHexString(charValue + 0x10000).toUpperCase().substring(1) + ";");
} else {
marc.append("&#x" + Integer.toHexString(charValue).toUpperCase() + ";");
// continue;
}
} else {
// need to change character set
// if several MARC-8 character sets contain the given Unicode character, select the
// best char set to use for encoding the character. Preference is given to character
// sets that have been used previously in the field being encoded. Since the default
// character sets for Basic and extended latin are pre-loaded, usually if a character
// can be encoded by one of those character sets, that is what will be chosen.
final int charset = rct.getBestCharSet(c);
final char[] marc8 = rct.getCharEntry(c, charset);
if (marc8.length == 3) {
marc.append(ESC);
marc.append(G0multibyte);
rct.setPreviousG0(charset);
} else if (marc8[0] < 0x80) {
marc.append(ESC);
if (charset == 0x62 || charset == 0x70) {
// technique1 = true;
} else {
marc.append(G0);
}
rct.setPreviousG0(charset);
} else {
marc.append(ESC);
marc.append(G1);
rct.setPreviousG1(charset);
}
marc.append((char) charset);
marc.append(marc8);
}
if (rct.isCombining(c) && sb.length() > 0) {
sb.insert(sb.length() - prev_len, marc);
// Special case handling to handle the COMBINING DOUBLE INVERTED BREVE
// and the COMBINING DOUBLE TILDE where a single double wide accent character
// in unicode is represented by two half characters in Marc8
if ((int) c == 0x360) {
sb.append((char) 0xfb);
}
if ((int) c == 0x361) {
sb.append((char) 0xec);
}
} else {
sb.append(marc);
}
prev_len = marc.length();
}
}
private static boolean allCharsHaveMatch(final ReverseCodeTable rct, final String str) {
for (final char c : str.toCharArray()) {
if (!rct.charHasMatch(c)) {
return false;
}
}
return true;
}
}