/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* $Id$ */
package org.apache.fop.complexscripts.util;
import org.apache.fop.util.CharUtilities;
/**
* <p>UTF32 related utilities.</p>
*
* <p>This work was originally authored by Glenn Adams (gadams@apache.org).</p>
*/
public final class UTF32 {
private UTF32() {
}
/**
* Convert Java string (UTF-16) to a Unicode scalar array (UTF-32).
* Note that if there are any non-BMP encoded characters present in the
* input, then the number of entries in the output array will be less
* than the number of elements in the input string. Any
* @param s input string
* @param substitution value to substitute for ill-formed surrogate
* @param errorOnSubstitution throw runtime exception (IllegalArgumentException) in
* case this argument is true and a substitution would be attempted
* @return output scalar array
* @throws IllegalArgumentException if substitution required and errorOnSubstitution
* is not false
*/
public static Integer[] toUTF32(String s, int substitution, boolean errorOnSubstitution)
throws IllegalArgumentException {
int n;
if ((n = s.length()) == 0) {
return new Integer[0];
} else {
Integer[] sa = new Integer [ n ];
int k = 0;
for (int i = 0; i < n; i++) {
int c = (int) s.charAt(i);
if ((c >= 0xD800) && (c < 0xE000)) {
int s1 = c;
int s2 = ((i + 1) < n) ? (int) s.charAt(i + 1) : 0;
if (s1 < 0xDC00) {
if ((s2 >= 0xDC00) && (s2 < 0xE000)) {
c = ((s1 - 0xD800) << 10) + (s2 - 0xDC00) + 65536;
i++;
} else {
if (errorOnSubstitution) {
throw new IllegalArgumentException(
"isolated high (leading) surrogate");
} else {
c = substitution;
}
}
} else {
if (errorOnSubstitution) {
throw new IllegalArgumentException(
"isolated low (trailing) surrogate");
} else {
c = substitution;
}
}
}
sa[k++] = c;
}
if (k == n) {
return sa;
} else {
Integer[] na = new Integer [ k ];
System.arraycopy(sa, 0, na, 0, k);
return na;
}
}
}
/**
* Convert a Unicode scalar array (UTF-32) a Java string (UTF-16).
* @param sa input scalar array
* @return output (UTF-16) string
* @throws IllegalArgumentException if an input scalar value is illegal,
* e.g., a surrogate or out of range
*/
public static String fromUTF32(Integer[] sa) throws IllegalArgumentException {
StringBuffer sb = new StringBuffer();
for (int s : sa) {
if (s < 65535) {
if ((s < 0xD800) || (s > 0xDFFF)) {
sb.append((char) s);
} else {
String ncr = CharUtilities.charToNCRef(s);
throw new IllegalArgumentException(
"illegal scalar value 0x" + ncr.substring(2, ncr.length() - 1)
+ "; cannot be UTF-16 surrogate");
}
} else if (s < 1114112) {
int s1 = (((s - 65536) >> 10) & 0x3FF) + 0xD800;
int s2 = (((s - 65536) >> 0) & 0x3FF) + 0xDC00;
sb.append((char) s1);
sb.append((char) s2);
} else {
String ncr = CharUtilities.charToNCRef(s);
throw new IllegalArgumentException(
"illegal scalar value 0x" + ncr.substring(2, ncr.length() - 1)
+ "; out of range for UTF-16");
}
}
return sb.toString();
}
}