/*
* 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.jackrabbit.webdav.util;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;
import java.util.BitSet;
/**
* <code>EncodeUtil</code> provides helper methods for URL encoding and decoding
* (copied from jcr-commons jackrabbit.util.Text).
*
* @see <a href="https://issues.apache.org/jira/browse/JCR-2897">JCR-2897</a>.
*/
public final class EncodeUtil {
/**
* logger instance
*/
private static final Logger log = LoggerFactory.getLogger(EncodeUtil.class);
/**
* hextable used for {@link #escape(String, char, boolean)}
*/
public static final char[] hexTable = "0123456789abcdef".toCharArray();
/**
* The list of characters that are not encoded by the <code>escape()</code>
* and <code>unescape()</code> METHODS. They contains the characters as
* defined 'unreserved' in section 2.3 of the RFC 2396 'URI generic syntax':
* <p>
* <pre>
* unreserved = alphanum | mark
* mark = "-" | "_" | "." | "!" | "~" | "*" | "'" | "(" | ")"
* </pre>
*/
private static BitSet URISave;
/**
* Same as {@link #URISave} but also contains the '/'
*/
private static BitSet URISaveEx;
static {
URISave = new BitSet(256);
int i;
for (i = 'a'; i <= 'z'; i++) {
URISave.set(i);
}
for (i = 'A'; i <= 'Z'; i++) {
URISave.set(i);
}
for (i = '0'; i <= '9'; i++) {
URISave.set(i);
}
URISave.set('-');
URISave.set('_');
URISave.set('.');
URISave.set('!');
URISave.set('~');
URISave.set('*');
URISave.set('\'');
URISave.set('(');
URISave.set(')');
URISaveEx = (BitSet) URISave.clone();
URISaveEx.set('/');
}
/**
* Does a URL encoding of the <code>string</code>. The characters that
* don't need encoding are those defined 'unreserved' in section 2.3 of
* the 'URI generic syntax' RFC 2396.
*
* @param string the string to encode
* @return the escaped string
* @throws NullPointerException if <code>string</code> is <code>null</code>.
*/
public static String escape(String string) {
return escape(string, '%', false);
}
/**
* Does a URL encoding of the <code>path</code>. The characters that
* don't need encoding are those defined 'unreserved' in section 2.3 of
* the 'URI generic syntax' RFC 2396. In contrast to the
* {@link #escape(String)} method, not the entire path string is escaped,
* but every individual part (i.e. the slashes are not escaped).
*
* @param path the path to encode
* @return the escaped path
* @throws NullPointerException if <code>path</code> is <code>null</code>.
*/
public static String escapePath(String path) {
return escape(path, '%', true);
}
/**
* Does an URL encoding of the <code>string</code> using the
* <code>escape</code> character. The characters that don't need encoding
* are those defined 'unreserved' in section 2.3 of the 'URI generic syntax'
* RFC 2396, but without the escape character. If <code>isPath</code> is
* <code>true</code>, additionally the slash '/' is ignored, too.
*
* @param string the string to encode.
* @param escape the escape character.
* @param isPath if <code>true</code>, the string is treated as path
* @return the escaped string
* @throws NullPointerException if <code>string</code> is <code>null</code>.
*/
private static String escape(String string, char escape, boolean isPath) {
try {
BitSet validChars = isPath ? URISaveEx : URISave;
byte[] bytes = string.getBytes("utf-8");
StringBuffer out = new StringBuffer(bytes.length);
for (byte aByte : bytes) {
int c = aByte & 0xff;
if (validChars.get(c) && c != escape) {
out.append((char) c);
} else {
out.append(escape);
out.append(hexTable[(c >> 4) & 0x0f]);
out.append(hexTable[(c) & 0x0f]);
}
}
return out.toString();
} catch (UnsupportedEncodingException e) {
throw new InternalError(e.toString());
}
}
/**
* Does a URL decoding of the <code>string</code>. Please note that in
* opposite to the {@link java.net.URLDecoder} it does not transform the +
* into spaces.
*
* @param string the string to decode
* @return the decoded string
* @throws NullPointerException if <code>string</code> is <code>null</code>.
* @throws ArrayIndexOutOfBoundsException if not enough character follow an
* escape character
* @throws IllegalArgumentException if the 2 characters following the escape
* character do not represent a hex-number.
*/
public static String unescape(String string) {
return unescape(string, '%');
}
/**
* Does a URL decoding of the <code>string</code> using the
* <code>escape</code> character. Please note that in opposite to the
* {@link java.net.URLDecoder} it does not transform the + into spaces.
*
* @param string the string to decode
* @param escape the escape character
* @return the decoded string
* @throws NullPointerException if <code>string</code> is <code>null</code>.
* @throws IllegalArgumentException if the 2 characters following the escape
* character do not represent a hex-number
* or if not enough characters follow an
* escape character
*/
private static String unescape(String string, char escape) {
try {
byte[] utf8 = string.getBytes("utf-8");
// Check whether escape occurs at invalid position
if ((utf8.length >= 1 && utf8[utf8.length - 1] == escape) ||
(utf8.length >= 2 && utf8[utf8.length - 2] == escape)) {
throw new IllegalArgumentException("Premature end of escape sequence at end of input");
}
ByteArrayOutputStream out = new ByteArrayOutputStream(utf8.length);
for (int k = 0; k < utf8.length; k++) {
byte b = utf8[k];
if (b == escape) {
out.write((decodeDigit(utf8[++k]) << 4) + decodeDigit(utf8[++k]));
}
else {
out.write(b);
}
}
return new String(out.toByteArray(), "utf-8");
}
catch (UnsupportedEncodingException e) {
throw new InternalError(e.toString());
}
}
private static byte decodeDigit(byte b) {
if (b >= 0x30 && b <= 0x39) {
return (byte) (b - 0x30);
}
else if (b >= 0x41 && b <= 0x46) {
return (byte) (b - 0x37);
}
else if (b >= 0x61 && b <= 0x66) {
return (byte) (b - 0x57);
}
else {
throw new IllegalArgumentException("Escape sequence is not hexadecimal: " + (char)b);
}
}
/**
* Private constructor: avoid instantiation.
*/
private EncodeUtil() {
}
}