net.sf.webdav.fromcatalina.MD5Encoder Maven / Gradle / Ivy
/*
* Copyright 1999,2004 The Apache Software Foundation.
*
* Licensed 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 net.sf.webdav.fromcatalina;
/**
* Encode an MD5 digest into a String.
*
* The 128 bit MD5 hash is converted into a 32 character long String. Each
* character of the String is the hexadecimal representation of 4 bits of the
* digest.
*
* @author Remy Maucherat
* @version $Revision: 1.2 $ $Date: 2008-08-05 07:38:45 $
*/
public final class MD5Encoder {
// ----------------------------------------------------- Instance Variables
private static final char[] HEXADECIMAL = { '0', '1', '2', '3', '4', '5',
'6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
// --------------------------------------------------------- Public Methods
/**
* Encodes the 128 bit (16 bytes) MD5 into a 32 character String.
*
* @param binaryData
* Array containing the digest
* @return Encoded MD5, or null if encoding failed
*/
public String encode(byte[] binaryData) {
if (binaryData.length != 16)
return null;
char[] buffer = new char[32];
for (int i = 0; i < 16; i++) {
int low = (int) (binaryData[i] & 0x0f);
int high = (int) ((binaryData[i] & 0xf0) >> 4);
buffer[i * 2] = HEXADECIMAL[high];
buffer[i * 2 + 1] = HEXADECIMAL[low];
}
return new String(buffer);
}
}