com.playonlinux.core.utils.ChecksumCalculator.java Source code

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Here is the source code for com.playonlinux.core.utils.ChecksumCalculator.java

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/*
 * Copyright (C) 2015 PRIS Quentin
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

package com.playonlinux.core.utils;

import static com.playonlinux.core.lang.Localisation.translate;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.function.Consumer;

import org.apache.commons.codec.binary.Hex;
import org.apache.commons.io.FileUtils;

import com.playonlinux.core.entities.ProgressEntity;

public class ChecksumCalculator {
    private static final int BLOCK_SIZE = 2048;
    private static final String WAIT_MESSAGE = translate("Please wait while we are verifying the file...");

    private Consumer<ProgressEntity> onChange;

    public String calculate(File fileToCheck, String algorithm) throws IOException {
        final long fileSize = FileUtils.sizeOf(fileToCheck);
        try (final FileInputStream inputStream = new FileInputStream(fileToCheck)) {
            MessageDigest messageDigest;
            try {
                messageDigest = MessageDigest.getInstance(algorithm);
            } catch (NoSuchAlgorithmException e) {
                throw new IllegalArgumentException(e);
            }

            byte[] digest = getDigest(inputStream, messageDigest, fileSize);
            return Hex.encodeHexString(digest);
        }
    }

    private byte[] getDigest(InputStream inputStream, MessageDigest messageDigest, long sizeInBytes)
            throws IOException {

        messageDigest.reset();
        byte[] bytes = new byte[BLOCK_SIZE];
        int numBytes;
        int readBytes = 0;
        while ((numBytes = inputStream.read(bytes)) != -1) {
            messageDigest.update(bytes, 0, numBytes);
            readBytes += numBytes;
            if (sizeInBytes != 0L) {
                double percentage = (double) readBytes / (double) sizeInBytes * (double) 100;
                changeState(percentage);
            }
        }
        return messageDigest.digest();
    }

    private void changeState(double percentage) {
        if (onChange != null) {
            onChange.accept(
                    new ProgressEntity.Builder().withPercent(percentage).withProgressText(WAIT_MESSAGE).build());
        }
    }

    public void setOnChange(Consumer<ProgressEntity> onChange) {
        this.onChange = onChange;
    }
}