package org.apache.commons.openpgp;

 /*

  * Licensed to the Apache Software Foundation (ASF) under one or more

  * contributor license agreements.  See the NOTICE file distributed with

  * this work for additional information regarding copyright ownership.

  * The ASF licenses this file to You 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 java.io.IOException;

 /**

  * An interface for updating an OpenPGP signature on the fly with streaming data.

  *

  * @author <a href="mailto:brett@apache.org">Brett Porter</a>

  */

 public interface OpenPgpStreamingSigner

 {

     String ROLE = OpenPgpStreamingSigner.class.getName();

     /**

      * Update the signature with the next block from the data buffer.

      *

      * @param buf the buffer

      * @throws OpenPgpException if the buffer is not valid for updating the signature

      */

     void update( byte[] buf )

         throws OpenPgpException;

     /**

      * Update the signature with the next block from the data buffer.

      *

      * @param buf    the buffer

      * @param offset offset within the buffer to start from

      * @param length number of bytes in the buffer to read from

      * @throws OpenPgpException if the buffer is not valid for updating the signature

      */

     void update( byte[] buf, int offset, int length )

         throws OpenPgpException;

     /**

      * Finish creating the signature.

      *

      * @return the completed signature

      * @throws OpenPgpException if the signature is not in a consistent or complete state

      */

     byte[] finish()

         throws OpenPgpException, IOException;

 }