/*************************************************************************
 * Copyright 2009-2012 Eucalyptus Systems, Inc.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 3 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see http://www.gnu.org/licenses/.
 *
 * Please contact Eucalyptus Systems, Inc., 6755 Hollister Ave., Goleta
 * CA 93117, USA or visit http://www.eucalyptus.com/licenses/ if you need
 * additional information or have any questions.
 *
 * This file may incorporate work covered under the following copyright
 * and permission notice:
 *
 *   Software License Agreement (BSD License)
 *
 *   Copyright (c) 2008, Regents of the University of California
 *   All rights reserved.
 *
 *   Redistribution and use of this software in source and binary forms,
 *   with or without modification, are permitted provided that the
 *   following conditions are met:
 *
 *     Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *     Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer
 *     in the documentation and/or other materials provided with the
 *     distribution.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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 *   BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *   LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 *   CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 *   POSSIBILITY OF SUCH DAMAGE. USERS OF THIS SOFTWARE ACKNOWLEDGE
 *   THE POSSIBLE PRESENCE OF OTHER OPEN SOURCE LICENSED MATERIAL,
 *   COPYRIGHTED MATERIAL OR PATENTED MATERIAL IN THIS SOFTWARE,
 *   AND IF ANY SUCH MATERIAL IS DISCOVERED THE PARTY DISCOVERING
 *   IT MAY INFORM DR. RICH WOLSKI AT THE UNIVERSITY OF CALIFORNIA,
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 *   WHICH IN THE REGENTS' DISCRETION MAY INCLUDE, WITHOUT LIMITATION,
 *   REPLACEMENT OF THE CODE SO IDENTIFIED, LICENSING OF THE CODE SO
 *   IDENTIFIED, OR WITHDRAWAL OF THE CODE CAPABILITY TO THE EXTENT
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 ************************************************************************/

package com.eucalyptus.crypto;

import java.nio.ByteBuffer;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import javax.crypto.Mac;
import org.apache.log4j.Logger;

public enum Hmac {
  HmacSHA1,
  HmacSHA256;

  private static Logger LOG = Logger.getLogger( Hmac.class );

  private final ThreadLocal<Mac> threadLocalMac = new ThreadLocal<Mac>() {
    @Override
    protected Mac initialValue( ) {
      final Mac mac = getInstance( );
      mac.reset( );
      return mac;
    }
  };

  public byte[] digestBinary( final Key key, final byte[] data ) throws InvalidKeyException {
    final Mac mac = threadLocalMac.get( );
    mac.init( key );
    return mac.doFinal( data );
  }

  public byte[] digestBinary( final Key key, final ByteBuffer data ) throws InvalidKeyException {
    final Mac mac = threadLocalMac.get( );
    mac.init( key );
    mac.update( data );
    return mac.doFinal( );
  }

  public Mac getInstance() {
    try {
      return Mac.getInstance( this.toString( ) );
    } catch ( NoSuchAlgorithmException e ) {
      LOG.fatal( e, e );
      throw new RuntimeException( e );
    }
  }
}