content: /*****************************************************************
   *   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
   *
   *    https://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.apache.cayenne.crypto.transformer.bytes;
  
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.util.zip.GZIPOutputStream;
  
  import org.apache.cayenne.crypto.CayenneCryptoException;
  
  /**
   * @since 4.0
   */
  class GzipEncryptor implements BytesEncryptor {
  
  	static final int GZIP_THRESHOLD = 150;
  
  	private BytesEncryptor delegate;
  
  	public GzipEncryptor(BytesEncryptor delegate) {
  		this.delegate = delegate;
  	}
  
  	@Override
  	public byte[] encrypt(byte[] input, int outputOffset, byte[] flags) {
  
  		boolean compressed = input.length >= GZIP_THRESHOLD;
  
  		if (compressed) {
  			try {
  				input = gzip(input);
  			} catch (IOException e) {
  				// really not expecting an error here...
  				throw new CayenneCryptoException("Error compressing input", e);
  			}
  		}
  
  		flags[0] = Header.setCompressed(flags[0], compressed);
  		return delegate.encrypt(input, outputOffset, flags);
  	}
  
  	static byte[] gzip(byte[] input) throws IOException {
  		ByteArrayOutputStream zipBytes = new ByteArrayOutputStream(input.length);
  		try (GZIPOutputStream out = new GZIPOutputStream(zipBytes);) {
  			out.write(input, 0, input.length);
  		}
  
  		return zipBytes.toByteArray();
  	}
  
  }
  