FullHasher.java

/*
 * This file is part of Fim - File Integrity Manager
 *
 * Copyright (C) 2017  Etienne Vrignaud
 *
 * Fim 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 3 of the License, or
 * (at your option) any later version.
 *
 * Fim 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 Fim.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.fim.internal.hash;

import org.fim.model.Context;
import org.fim.model.HashMode;
import org.fim.model.Range;
import org.fim.util.HashModeUtil;

import java.nio.ByteBuffer;
import java.security.NoSuchAlgorithmException;

import static java.lang.Math.min;
import static org.fim.model.Constants._1_MB;
import static org.fim.model.HashMode.hashAll;

public class FullHasher extends AbstractHasher {
    public static final int BLOCK_SIZE = 30 * _1_MB;

    private long fileSize;

    public FullHasher(Context context) throws NoSuchAlgorithmException {
        super(context);
    }

    @Override
    protected boolean isCompatible(HashMode hashMode) {
        return HashModeUtil.isCompatible(hashMode, hashAll);
    }

    @Override
    public void reset(long fileSize) {
        super.reset(fileSize);

        if (isActive()) {
            this.fileSize = fileSize;
        }
    }

    @Override
    public Range getNextRange(long filePosition) {
        long from = filePosition;
        long to = min(fileSize, filePosition + BLOCK_SIZE);
        return new Range(from, to);
    }

    @Override
    protected ByteBuffer getNextBlockToHash(long filePosition, long currentPosition, ByteBuffer buffer) {
        return buffer;
    }

    @Override
    public boolean hashComplete() {
        if (isActive()) {
            return getBytesHashed() == fileSize;
        } else {
            return true;
        }
    }
}