gov.nist.javax.sip.address.RFC2396UrlDecoder Maven / Gradle / Ivy
/*
* Conditions Of Use
*
* This software was developed by employees of the National Institute of
* Standards and Technology (NIST), an agency of the Federal Government.
* Pursuant to title 15 Untied States Code Section 105, works of NIST
* employees are not subject to copyright protection in the United States
* and are considered to be in the public domain. As a result, a formal
* license is not needed to use the software.
*
* This software is provided by NIST as a service and is expressly
* provided "AS IS." NIST MAKES NO WARRANTY OF ANY KIND, EXPRESS, IMPLIED
* OR STATUTORY, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTY OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT
* AND DATA ACCURACY. NIST does not warrant or make any representations
* regarding the use of the software or the results thereof, including but
* not limited to the correctness, accuracy, reliability or usefulness of
* the software.
*
* Permission to use this software is contingent upon your acceptance
* of the terms of this agreement
*
* .
*
*/
package gov.nist.javax.sip.address;
import java.io.UnsupportedEncodingException;
/**
* Copied from Apache Excalibur project.
* Source code available at http://www.google.com/codesearch?hl=en&q=+excalibur+decodePath+show:sK_gDY0W5Rw:OTjCHAiSuF0:th3BdHtpX20&sa=N&cd=1&ct=rc&cs_p=http://apache.edgescape.com/excalibur/excalibur-sourceresolve/source/excalibur-sourceresolve-1.1-src.zip&cs_f=excalibur-sourceresolve-1.1/src/java/org/apache/excalibur/source/SourceUtil.java
* @author Jean Deruelle
*
*/
public class RFC2396UrlDecoder {
/**
* Decode a path.
*
* Interprets %XX (where XX is hexadecimal number) as UTF-8 encoded bytes.
*
The validity of the input path is not checked (i.e. characters that
* were not encoded will not be reported as errors).
*
This method differs from URLDecoder.decode in that it always uses UTF-8
* (while URLDecoder uses the platform default encoding, often ISO-8859-1),
* and doesn't translate + characters to spaces.
*
* @param uri the path to decode
* @return the decoded path
*/
public static String decode(String uri) {
StringBuffer translatedUri = new StringBuffer(uri.length());
byte[] encodedchars = new byte[uri.length() / 3];
int i = 0;
int length = uri.length();
int encodedcharsLength = 0;
while (i < length) {
if (uri.charAt(i) == '%') {
//we must process all consecutive %-encoded characters in one go, because they represent
//an UTF-8 encoded string, and in UTF-8 one character can be encoded as multiple bytes
while (i < length && uri.charAt(i) == '%') {
if (i + 2 < length) {
try {
byte x = (byte)Integer.parseInt(uri.substring(i + 1, i + 3), 16);
encodedchars[encodedcharsLength] = x;
} catch (NumberFormatException e) {
throw new IllegalArgumentException("Illegal hex characters in pattern %" + uri.substring(i + 1, i + 3));
}
encodedcharsLength++;
i += 3;
} else {
throw new IllegalArgumentException("% character should be followed by 2 hexadecimal characters.");
}
}
try {
String translatedPart = new String(encodedchars, 0, encodedcharsLength, "UTF-8");
translatedUri.append(translatedPart);
} catch (UnsupportedEncodingException e) {
//the situation that UTF-8 is not supported is quite theoretical, so throw a runtime exception
throw new RuntimeException("Problem in decodePath: UTF-8 encoding not supported.");
}
encodedcharsLength = 0;
} else {
//a normal character
translatedUri.append(uri.charAt(i));
i++;
}
}
return translatedUri.toString();
}
}