/*
 * Copyright 2011 Future Systems, 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.
 */
package org.araqne.logdb.impl;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class HashUtils {
	public static String hashPassword(String salt, String password, String algorithm) {
		if (password == null)
			return null;
		return hash(((salt == null) ? "" : salt) + password, algorithm);
	}

	public static String hash(String text, String algorithm) {
		try {
			MessageDigest md = MessageDigest.getInstance(algorithm);
			md.update(text.getBytes("utf-8"), 0, text.length());
			byte[] sha1hash = md.digest();
			return convertToHex(sha1hash);
		} catch (UnsupportedEncodingException e) {
			// ignore
		} catch (NoSuchAlgorithmException e) {
			// ignore
		}

		return null;
	}

	private static String convertToHex(byte[] data) {
		StringBuffer buf = new StringBuffer();
		for (int i = 0; i < data.length; i++) {
			int halfbyte = (data[i] >>> 4) & 0x0F;
			int two_halfs = 0;
			do {
				if ((0 <= halfbyte) && (halfbyte <= 9))
					buf.append((char) ('0' + halfbyte));
				else
					buf.append((char) ('a' + (halfbyte - 10)));
				halfbyte = data[i] & 0x0F;
			} while (two_halfs++ < 1);
		}
		return buf.toString();
	}
}