/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-09 The eXist Project
* http://exist-db.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* $Id$
*/
package org.exist.xquery.modules.compression;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.zip.GZIPOutputStream;
import org.apache.commons.io.output.ByteArrayOutputStream;
import org.exist.dom.QName;
import org.exist.xquery.BasicFunction;
import org.exist.xquery.Cardinality;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.Base64BinaryValueType;
import org.exist.xquery.value.BinaryValue;
import org.exist.xquery.value.BinaryValueFromInputStream;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
/**
* Compression into a GZip file
*
* @author Adam Retter <adam@exist-db.org>
* @version 1.1
*/
public class GZipFunction extends BasicFunction
{
public final static FunctionSignature signatures[] = {
new FunctionSignature(
new QName("gzip", CompressionModule.NAMESPACE_URI, CompressionModule.PREFIX),
"GZip's data",
new SequenceType[] {
new FunctionParameterSequenceType("data", Type.BASE64_BINARY, Cardinality.EXACTLY_ONE, "The data to GZip")
},
new SequenceType(
Type.BASE64_BINARY, Cardinality.ZERO_OR_ONE)
)
};
public GZipFunction(XQueryContext context, FunctionSignature signature)
{
super(context, signature);
}
@Override
public Sequence eval(Sequence[] args, Sequence contextSequence) throws XPathException
{
// is there some data to GZip?
if(args[0].isEmpty())
return Sequence.EMPTY_SEQUENCE;
BinaryValue bin = (BinaryValue) args[0].itemAt(0);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
// gzip the data
try
{
GZIPOutputStream gzos = new GZIPOutputStream(baos);
bin.streamTo(gzos);
gzos.close();
return BinaryValueFromInputStream.getInstance(context, new Base64BinaryValueType(), new ByteArrayInputStream(baos.toByteArray()));
}
catch(IOException ioe)
{
throw new XPathException(this, ioe.getMessage());
}
}
}