Java Checksum Calculate calculateChecksums(Optional zos, InputStream inputStream, Set checksumAlgorithms)

Description

calculate Checksums

License

LGPL

Declaration

public static Map<String, String> calculateChecksums(Optional<ZipOutputStream> zos, InputStream inputStream,
            Set<String> checksumAlgorithms) throws NoSuchAlgorithmException, IOException 

Method Source Code

//package com.java2s;
//License from project: LGPL 

import java.io.IOException;
import java.io.InputStream;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Optional;
import java.util.Set;

import java.util.zip.ZipOutputStream;
import javax.xml.bind.DatatypeConverter;

public class Main {
    public static Map<String, String> calculateChecksums(Optional<ZipOutputStream> zos, InputStream inputStream,
            Set<String> checksumAlgorithms) throws NoSuchAlgorithmException, IOException {
        byte[] buffer = new byte[4096];
        Map<String, String> values = new HashMap<>();

        // instantiate different checksum algorithms
        Map<String, MessageDigest> algorithms = new HashMap<>();
        for (String alg : checksumAlgorithms) {
            algorithms.put(alg, MessageDigest.getInstance(alg));
        }//from w  w w  .  j av  a2  s.  com

        // calculate value for each one of the algorithms
        int numRead;
        do {
            numRead = inputStream.read(buffer);
            if (numRead > 0) {
                for (Entry<String, MessageDigest> alg : algorithms.entrySet()) {
                    alg.getValue().update(buffer, 0, numRead);
                }

                if (zos.isPresent()) {
                    zos.get().write(buffer, 0, numRead);
                }
            }
        } while (numRead != -1);

        // generate hex versions of the digests
        algorithms.forEach((alg, dig) -> values.put(alg, DatatypeConverter.printHexBinary(dig.digest())));

        return values;
    }
}

Related

1. calcChecksum(byte[] buffer, int start, int end)
2. calcCheckSum(byte[] bytes, int num)
3. calcCheckSum(byte[] data, int offset, int maxIdx)
4. calcChecksum(String value, int length)
5. calculateChecksum(InputStream is, String algorithm)
6. checkSum(boolean[] a)
7. checkSum(byte abyte0[])
8. checksum(byte current, final byte[] data, final int offset, final int length)
9. checkSum(byte value)