org.apache.commons.lang3.text.translate.OctalUnescaper Maven / Gradle / Ivy
/*
* 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.
*/
package org.apache.commons.lang3.text.translate;
import java.io.IOException;
import java.io.Writer;
/**
* Translate escaped octal Strings back to their octal values.
*
* For example, "\45" should go back to being the specific value (a %).
*
* Note that this currently only supports the viable range of octal for Java; namely
* 1 to 377. This is both because parsing Java is the main use case and Integer.parseInt
* throws an exception when values are larger than octal 377.
*
* @since 3.0
* @version $Id: OctalUnescaper.java 967237 2010-07-23 20:08:57Z mbenson $
*/
public class OctalUnescaper extends CharSequenceTranslator {
private static int OCTAL_MAX = 377;
/**
* {@inheritDoc}
*/
@Override
public int translate(CharSequence input, int index, Writer out) throws IOException {
if(input.charAt(index) == '\\' && index < (input.length() - 1) && Character.isDigit(input.charAt(index + 1)) ) {
int start = index + 1;
int end = index + 2;
while ( end < input.length() && Character.isDigit(input.charAt(end)) ) {
end++;
if ( Integer.parseInt(input.subSequence(start, end).toString(), 10) > OCTAL_MAX) {
end--; // rollback
break;
}
}
out.write( Integer.parseInt(input.subSequence(start, end).toString(), 8) );
return 1 + end - start;
}
return 0;
}
}