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* 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
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* KIND, either express or implied. See the License for the
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package org.apache.cayenne.crypto.transformer.bytes;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.security.Key;
import java.util.Arrays;
import java.util.zip.GZIPInputStream;
import org.apache.cayenne.crypto.CayenneCryptoException;
/**
* @since 4.0
*/
class GzipDecryptor implements BytesDecryptor {
private BytesDecryptor delegate;
public GzipDecryptor(BytesDecryptor delegate) {
this.delegate = delegate;
}
@Override
public byte[] decrypt(byte[] input, int inputOffset, Key key) {
byte[] decrypted = delegate.decrypt(input, inputOffset, key);
try {
return gunzip(decrypted);
} catch (IOException e) {
// really not expecting an error here...
throw new CayenneCryptoException("Error uncompressing input", e);
}
}
static byte[] gunzip(byte[] input) throws IOException {
ByteArrayInputStream zipBytes = new ByteArrayInputStream(input);
GZIPInputStream in = new GZIPInputStream(zipBytes);
// duplicating ByteArrayOutputStream logic here... too much overhead and
// inefficiency using ByteArrayOutputStream directly
byte[] out = new byte[input.length * 2];
int totalRead = 0;
int read;
int resizeBy = input.length;
while ((read = in.read(out, totalRead, out.length - totalRead - 1)) > 0) {
totalRead += read;
if (totalRead + 1 == out.length) {
out = Arrays.copyOf(out, out.length + resizeBy);
}
}
if (totalRead < out.length) {
out = Arrays.copyOf(out, totalRead);
}
return out;
}
}