/*****************************************************************
* 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.
****************************************************************/
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();
}
}