org.springframework.data.redis.core.script.DigestUtils Maven / Gradle / Ivy
/*
* Copyright 2013-2018 the original author or authors.
*
* 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 org.springframework.data.redis.core.script;
import java.nio.charset.Charset;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/**
* Utilties for working with {@link MessageDigest}
*
* @author Jennifer Hickey
*/
abstract public class DigestUtils {
private static final char[] HEX_CHARS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e',
'f' };
private static final Charset UTF8_CHARSET = Charset.forName("UTF8");
/**
* Returns the SHA1 of the provided data
*
* @param data The data to calculate, such as the contents of a file
* @return The human-readable SHA1
*/
public static String sha1DigestAsHex(String data) {
byte[] dataBytes = getDigest("SHA").digest(data.getBytes(UTF8_CHARSET));
return new String(encodeHex(dataBytes));
}
private static char[] encodeHex(byte[] data) {
int l = data.length;
char[] out = new char[l << 1];
for (int i = 0, j = 0; i < l; i++) {
out[j++] = HEX_CHARS[(0xF0 & data[i]) >>> 4];
out[j++] = HEX_CHARS[0x0F & data[i]];
}
return out;
}
/**
* Creates a new {@link MessageDigest} with the given algorithm. Necessary because {@code MessageDigest} is not
* thread-safe.
*/
private static MessageDigest getDigest(String algorithm) {
try {
return MessageDigest.getInstance(algorithm);
} catch (NoSuchAlgorithmException ex) {
throw new IllegalStateException("Could not find MessageDigest with algorithm \"" + algorithm + "\"", ex);
}
}
}