package com.nimbusds.jose.crypto;
import net.jcip.annotations.ThreadSafe;
import com.nimbusds.jose.CompressionAlgorithm;
import com.nimbusds.jose.JOSEException;
import com.nimbusds.jose.ReadOnlyJWEHeader;
import com.nimbusds.jose.util.DeflateUtils;
/**
* Deflate (RFC 1951) helper methods, intended for use by JWE encrypters and
* decrypters. This class is thread-safe.
*
* @author Vladimir Dzhuvinov
* @version $version$ (2013-04-16)
*/
@ThreadSafe
class DeflateHelper {
/**
* Applies compression to the specified plain text if requested.
*
* @param readOnlyJWEHeader The JWE header. Must not be {@code null}.
* @param bytes The plain text bytes. Must not be
* {@code null}.
*
* @return The bytes to encrypt.
*
* @throws JOSEException If compression failed or the requested
* compression algorithm is not supported.
*/
public static byte[] applyCompression(final ReadOnlyJWEHeader readOnlyJWEHeader, final byte[] bytes)
throws JOSEException {
CompressionAlgorithm compressionAlg = readOnlyJWEHeader.getCompressionAlgorithm();
if (compressionAlg == null) {
return bytes;
} else if (compressionAlg.equals(CompressionAlgorithm.DEF)) {
try {
return DeflateUtils.compress(bytes);
} catch (Exception e) {
throw new JOSEException("Couldn't compress plain text: " + e.getMessage(), e);
}
} else {
throw new JOSEException("Unsupported compression algorithm: " + compressionAlg);
}
}
/**
* Applies decompression to the specified plain text if requested.
*
* @param readOnlyJWEHeader The JWE header. Must not be {@code null}.
* @param bytes The plain text bytes. Must not be
* {@code null}.
*
* @return The output bytes, decompressed if requested.
*
* @throws JOSEException If decompression failed or the requested
* compression algorithm is not supported.
*/
public static byte[] applyDecompression(final ReadOnlyJWEHeader readOnlyJWEHeader, final byte[] bytes)
throws JOSEException {
CompressionAlgorithm compressionAlg = readOnlyJWEHeader.getCompressionAlgorithm();
if (compressionAlg == null) {
return bytes;
} else if (compressionAlg.equals(CompressionAlgorithm.DEF)) {
try {
return DeflateUtils.decompress(bytes);
} catch (Exception e) {
throw new JOSEException("Couldn't decompress plain text: " + e.getMessage(), e);
}
} else {
throw new JOSEException("Unsupported compression algorithm: " + compressionAlg);
}
}
}