package brickhouse.udf.sketch;
/**
 * Copyright 2012 Klout, Inc
 *
 * 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.
 *
 **/

import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.io.Text;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * Calculate md5 of the string
 */
public final class Md5 extends UDF {

    public Text evaluate(final Text s) {
        if (s == null) {
            return null;
        }
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            md.update(s.toString().getBytes());
            byte[] md5hash = md.digest();
            StringBuilder builder = new StringBuilder();
            for (byte b : md5hash) {
                builder.append(Integer.toString((b & 0xff) + 0x100, 16).substring(1));
            }
            return new Text(builder.toString());
        } catch (NoSuchAlgorithmException nsae) {
            System.out.println("Cannot find digest algorithm");
            System.exit(1);
        }
        return null;
    }
}
