content: /*
   * Copyright (C) 2016 The Android Open Source Project
   *
   * 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 com.android.apksig.internal.util;
  
  import com.android.apksig.util.DataSink;
  import java.nio.ByteBuffer;
  import java.security.MessageDigest;
  
  /**
   * Data sink which feeds all received data into the associated {@link MessageDigest} instances. Each
   * {@code MessageDigest} instance receives the same data.
   */
  public class MessageDigestSink implements DataSink {
  
      private final MessageDigest[] mMessageDigests;
  
      public MessageDigestSink(MessageDigest[] digests) {
          mMessageDigests = digests;
      }
  
      @Override
      public void consume(byte[] buf, int offset, int length) {
          for (MessageDigest md : mMessageDigests) {
              md.update(buf, offset, length);
          }
      }
  
      @Override
      public void consume(ByteBuffer buf) {
          int originalPosition = buf.position();
          for (MessageDigest md : mMessageDigests) {
              // Reset the position back to the original because the previous iteration's
              // MessageDigest.update set the buffer's position to the buffer's limit.
              buf.position(originalPosition);
              md.update(buf);
          }
      }
  }
  