package org.jboss.resteasy.jose.jwe.crypto;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.Deflater;
import java.util.zip.DeflaterOutputStream;
import java.util.zip.Inflater;
import java.util.zip.InflaterInputStream;
/**
* Deflate (RFC 1951) utilities.
*
* @author Vladimir Dzhuvinov
* @version $version$ (2013-04-16)
*/
public class DeflateUtils
{
/**
* Omit headers and CRC fields from output, as specified by RFC 1950.
* Note that the Deflater JavaDocs are incorrect, see
* http://stackoverflow.com/questions/11076060/decompressing-gzipped-data-with-inflater-in-java
*/
private static final boolean NOWRAP = true;
/**
* Compresses the specified byte array according to the DEFLATE
* specification (RFC 1951).
*
* @param bytes The byte array to compress. Must not be {@code null}.
*
* @return The compressed bytes.
*
* @throws java.io.IOException If compression failed.
*/
public static byte[] compress(final byte[] bytes)
throws IOException {
ByteArrayOutputStream out = new ByteArrayOutputStream();
DeflaterOutputStream def = new DeflaterOutputStream(out, new Deflater(Deflater.DEFLATED, NOWRAP));
def.write(bytes);
def.close();
return out.toByteArray();
}
/**
* Decompresses the specified byte array according to the DEFLATE
* specification (RFC 1951).
*
* @param bytes The byte array to decompress. Must not be {@code null}.
*
* @return The decompressed bytes.
*
* @throws java.io.IOException If decompression failed.
*/
public static byte[] decompress(final byte[] bytes)
throws IOException {
InflaterInputStream inf = new InflaterInputStream(new ByteArrayInputStream(bytes), new Inflater(NOWRAP));
ByteArrayOutputStream out = new ByteArrayOutputStream();
// Transfer bytes from the compressed array to the output
byte[] buf = new byte[1024];
int len;
while ((len = inf.read(buf)) > 0) {
out.write(buf, 0, len);
}
inf.close();
out.close();
return out.toByteArray();
}
/**
* Prevents public instantiation.
*/
private DeflateUtils() {
}
}