de.upb.wdqa.wdvd.revisiontags.SHA1Converter.java Source code

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Here is the source code for de.upb.wdqa.wdvd.revisiontags.SHA1Converter.java

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/*
 * Wikidata Vandalism Detector 2016 (WDVD-2016)
 * 
 * Copyright (c) 2016 Stefan Heindorf, Martin Potthast, Benno Stein, Gregor Engels
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package de.upb.wdqa.wdvd.revisiontags;

import java.math.BigInteger;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class SHA1Converter {
    static final Logger logger = LoggerFactory.getLogger(SHA1Converter.class);

    private SHA1Converter() {

    }

    public static String base16to36(String base16) {
        byte[] sha1 = parseByte(16, base16);

        return getBase36(sha1);
    }

    public static byte[] parseByte16(String base16) {
        return parseByte(16, base16);
    }

    public static byte[] parseByte36(String base36) {
        return parseByte(36, base36);
    }

    private static byte[] parseByte(int base, String sha1) {
        byte[] result = null;
        if (sha1 != null) {
            if (!sha1.equals("")) {
                try {
                    BigInteger bi = new BigInteger(sha1, base);
                    result = bi.toByteArray();

                } catch (Exception e) {
                    logger.error("", e);
                }
            } else {
                result = new byte[0];
            }
        }
        return result;

    }

    public static String getBase16(byte[] bytes) {
        return getBase(16, bytes);
    }

    public static String getBase36(byte[] bytes) {
        return getBase(36, bytes);
    }

    private static String getBase(int base, byte[] bytes) {
        String result;

        if (bytes != null) {
            if (bytes.length != 0) {
                BigInteger bi = new BigInteger(1, bytes);
                String tmp = bi.toString(base);

                int numberOfDigits = (int) Math.ceil(160.0 / (Math.log(base) / Math.log(2.0)));

                result = StringUtils.leftPad(tmp, numberOfDigits, '0');
            } else {
                result = "";
            }
        } else {
            result = null;
        }

        return result;
    }

}