org.spdx.utility.verificationcode.JavaSha1ChecksumGenerator Maven / Gradle / Ivy
/**
* Copyright (c) 2011 Source Auditor Inc.
*
* Licensed 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 "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.spdx.utility.verificationcode;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/**
* Java sha1 checksum generator using MessageDigest
* @author Gary O'Neall
*
*/
public class JavaSha1ChecksumGenerator implements IFileChecksumGenerator {
static final String SHA1_ALGORITHM = "SHA-1";
static final String PACKAGE_VERIFICATION_CHARSET = "UTF-8";
private final MessageDigest digest;
/**
* Create a SHA1 based checksum generator
* @throws NoSuchAlgorithmException if the SHA1 algorithm does not exist
*/
public JavaSha1ChecksumGenerator() throws NoSuchAlgorithmException {
this.digest = MessageDigest.getInstance(SHA1_ALGORITHM);
}
/**
*
* @param file File to generate the checksum for
* @return file checksum
* @throws IOException on IO errors
*/
@Override
public String getFileChecksum(File file) throws IOException {
digest.reset();
try (FileInputStream in = new FileInputStream(file)) {
byte[] buffer = new byte[2048];
int numBytes = in.read(buffer);
while (numBytes >= 0) {
digest.update(buffer, 0, numBytes);
numBytes = in.read(buffer);
}
byte[] digestBytes = digest.digest();
StringBuilder sb = new StringBuilder();
for (byte digestByte : digestBytes) {
String hex = Integer.toHexString(0xff & digestByte);
if (hex.length() < 2) {
sb.append('0');
}
sb.append(hex);
}
return sb.toString();
}
}
}