/*
* Copyright 2015 Red Hat, Inc. and/or its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
*
* 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.eclipse.webdav.internal.utils;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.StringTokenizer;
import org.eclipse.webdav.Policy;
import org.eclipse.webdav.internal.kernel.utils.Assert;
/**
* Decodes a <code>URL</code> from an <code>ASCII</code> readable
* <code>URL</code> that is safe for transport.
*
* @see URLEncoder
*/
public final class URLDecoder {
private static final byte[] hexChars = {(byte) '0', //
(byte) '1', //
(byte) '2', //
(byte) '3', //
(byte) '4', //
(byte) '5', //
(byte) '6', //
(byte) '7', //
(byte) '8', //
(byte) '9', //
(byte) 'a', //
(byte) 'b', //
(byte) 'c', //
(byte) 'd', //
(byte) 'e', //
(byte) 'f', //
(byte) 'A', //
(byte) 'B', //
(byte) 'C', //
(byte) 'D', //
(byte) 'E', //
(byte) 'F'};
private static final byte[] hexCharValues = {(byte) ('0' - '0'), //
(byte) ('1' - '0'), //
(byte) ('2' - '0'), //
(byte) ('3' - '0'), //
(byte) ('4' - '0'), //
(byte) ('5' - '0'), //
(byte) ('6' - '0'), //
(byte) ('7' - '0'), //
(byte) ('8' - '0'), //
(byte) ('9' - '0'), //
(byte) ('a' - 'a' + 10), //
(byte) ('b' - 'a' + 10), //
(byte) ('c' - 'a' + 10), //
(byte) ('d' - 'a' + 10), //
(byte) ('e' - 'a' + 10), //
(byte) ('f' - 'a' + 10), //
(byte) ('A' - 'A' + 10), //
(byte) ('B' - 'A' + 10), //
(byte) ('C' - 'A' + 10), //
(byte) ('D' - 'A' + 10), //
(byte) ('E' - 'A' + 10), //
(byte) ('F' - 'A' + 10)};
/**
* Prevents instances from being created.
*/
private URLDecoder() {
super();
}
/**
* Decodes the given <code>URL</code> from an <code>ASCII</code>
* readable <code>URL</code> that is safe for transport. Returns the
* result.
*
* @return the result of decoding the given <code>URL</code> from an
* <code>ASCII</code> readable <code>URL</code> that is safe for
* transport
*/
public static String decode(String url) {
try {
return decode(new URL(url)).toString();
} catch (MalformedURLException e) {
// ignore or log?
}
String file;
String ref = null;
int lastSlashIndex = url.lastIndexOf('/');
int lastHashIndex = url.lastIndexOf('#');
if ((lastHashIndex - lastSlashIndex > 1) && lastHashIndex < url.length() - 1) {
file = url.substring(0, lastHashIndex);
ref = url.substring(lastHashIndex + 1, url.length());
} else {
file = url;
}
return decode(file, ref);
}
/**
* Decodes the file and reference parts of a <code>URL</code> from an
* <code>ASCII</code> readable <code>URL</code> that is safe for
* transport. Returns the result.
*
* @return the result of decoding the file and reference parts of a
* <code>URL</code> from an <code>ASCII</code> readable
* <code>URL</code> that is safe for transport
*/
public static String decode(String file, String ref) {
StringBuffer buf = new StringBuffer();
StringTokenizer tokenizer = new StringTokenizer(file, "/", true); //$NON-NLS-1$
while (tokenizer.hasMoreTokens()) {
String token = tokenizer.nextToken();
if (token.equals("/")) { //$NON-NLS-1$
buf.append(token);
} else {
buf.append(decodeSegment(token));
}
}
if (ref != null) {
buf.append('#');
buf.append(decodeSegment(ref));
}
return buf.toString();
}
/**
* Decodes the given <code>URL</code> from an <code>ASCII</code>
* readable <code>URL</code> that is safe for transport. Returns the
* result.
*
* @return the result of decoding the given <code>URL</code> from an
* <code>ASCII</code> readable <code>URL</code> that is safe for
* transport
*/
public static URL decode(URL url) {
String file = url.getFile();
String ref = url.getRef();
try {
return new URL(url.getProtocol(), url.getHost(), url.getPort(), decode(file, ref));
} catch (MalformedURLException e) {
Assert.isTrue(false, Policy.bind("assert.internalError")); //$NON-NLS-1$
}
return null;
}
public static String decodeSegment(String segment) {
byte[] encodedBytes = segment.getBytes();
byte[] decodedBytes = new byte[encodedBytes.length];
int decodedLength = 0;
for (int i = 0; i < encodedBytes.length; i++) {
byte b = encodedBytes[i];
try {
if (b == '%') {
byte enc1 = encodedBytes[++i];
byte enc2 = encodedBytes[++i];
b = (byte) ((hexToByte(enc1) << 4) + hexToByte(enc2));
}
decodedBytes[decodedLength++] = b;
} catch (ArrayIndexOutOfBoundsException e) {
Assert.isTrue(false, Policy.bind("assert.decodeSegment")); //$NON-NLS-1$
} catch (IllegalArgumentException e) {
Assert.isTrue(false, Policy.bind("assert.decodeSegment")); //$NON-NLS-1$
}
}
try {
return new String(decodedBytes, 0, decodedLength, "UTF8"); //$NON-NLS-1$
} catch (UnsupportedEncodingException exception) {
Assert.isTrue(false, Policy.bind("assert.internalError")); //$NON-NLS-1$
// avoid compiler error
return null;
}
}
private final static byte hexToByte(byte ch) {
for (int i = 0; i < hexChars.length; i++)
if (hexChars[i] == ch)
return hexCharValues[i];
throw new IllegalArgumentException();
}
}