eu.europa.esig.dss.spi.DSSMessageDigestCalculator Maven / Gradle / Ivy
/**
* DSS - Digital Signature Services
* Copyright (C) 2015 European Commission, provided under the CEF programme
*
* This file is part of the "DSS - Digital Signature Services" project.
*
* This library 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 2.1 of the License, or (at your option) any later version.
*
* This library 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 Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
package eu.europa.esig.dss.spi;
import eu.europa.esig.dss.enumerations.DigestAlgorithm;
import eu.europa.esig.dss.model.DSSException;
import eu.europa.esig.dss.model.DSSMessageDigest;
import java.io.IOException;
import java.io.InputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/**
* This class is used to compute {@code DSSMessageDigest} based on the provided input
*
*/
public class DSSMessageDigestCalculator {
/** The DigestAlgorithm used to compute message-digest */
private final DigestAlgorithm digestAlgorithm;
/** The java message-digest implementation used in calculations */
private final MessageDigest messageDigest;
/**
* Default constructor
*
* @param digestAlgorithm {@link DigestAlgorithm} to be used for message-digest computation
*/
public DSSMessageDigestCalculator(DigestAlgorithm digestAlgorithm) {
this.digestAlgorithm = digestAlgorithm;
this.messageDigest = toMessageDigest(digestAlgorithm);
}
private MessageDigest toMessageDigest(DigestAlgorithm digestAlgorithm) {
try {
return digestAlgorithm.getMessageDigest();
} catch (NoSuchAlgorithmException e) {
throw new DSSException(String.format("Unable to build MessageDigest for the algorithm '%s' : %s",
digestAlgorithm.getName(), e.getMessage()), e);
}
}
/**
* Updates the digest using the provided byte
*
* @param byteToAdd byte to be added for digest computation
*/
public void update(byte byteToAdd) {
messageDigest.update(byteToAdd);
}
/**
* Updates the digest using the provided array of bytes
*
* @param bytes array of bytes
*/
public void update(byte[] bytes) {
if (bytes != null) {
messageDigest.update(bytes);
}
}
/**
* Updates the digest by reading the provided {@code InputStream}.
* NOTE: the method consumes the {@code InputStream}, and closes it after.
*
* @param inputStream {@link InputStream}
* @throws IOException if an error is thrown on InputStream reading
*/
public void update(InputStream inputStream) throws IOException {
if (inputStream == null) {
return;
}
try (InputStream is = inputStream) {
int count;
byte[] buffer = new byte[4096];
while ((count = is.read(buffer)) >= 0) {
messageDigest.update(buffer, 0, count);
}
}
}
/**
* Returns the {@code DSSMessageDigest} accordingly to the current state.
* This method resets the state of message-digest.
*
* @return {@link DSSMessageDigest}
*/
public DSSMessageDigest getMessageDigest() {
return new DSSMessageDigest(digestAlgorithm, messageDigest.digest());
}
}