org.sinekartads.util.HexUtils.java Source code

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Here is the source code for org.sinekartads.util.HexUtils.java

Source

package org.sinekartads.util;

import java.io.ByteArrayInputStream;
import java.io.InputStream;

import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.lang3.Conversion;
import org.apache.commons.lang3.StringUtils;

/*
 * Copyright (C) 2010 - 2012 Jenia Software.
 *
 * This file is part of Sinekarta
 *
 * Sinekarta 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.
 *
 * Sinekarta 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.
 *
 */

public class HexUtils {

    // -----
    // --- Hex encode:          byte[] | boolean[] | long -> String
    // -

    /**
     * converting a byte[] to it's hexadecimal format String
     * 
     * @param buf the bytes to convert
     * @return the hex String corresponding to buf
     */
    public static String encodeHex(byte[] buf) {
        if (buf == null)
            return null;
        return Hex.encodeHexString(buf);
    }

    /**
     * converting a boolean[] to it's hexadecimal format String
     * 
     * @param buf the bytes to convert
     * @return the hex String corresponding to buf
     */
    public static String encodeHex(boolean... buf) {
        if (buf == null)
            return null;
        final int bytesNumber = buf.length / 8;
        final int offset = buf.length % 8;
        byte[] bytes = new byte[bytesNumber];
        byte tmpByte;
        for (int block = bytesNumber - 1; block >= 0; block--) {
            tmpByte = 0;
            for (int bit = 8 - 1; bit >= 0; bit--) {
                tmpByte += buf[block * 8 + bit - offset] ? 1 : 0;
                tmpByte = Integer.valueOf(tmpByte << 8).byteValue();
            }
            bytes[block] = tmpByte;
        }
        // TODO verify that works, i.e. encodeHex(true,false,false,true) -> "09"
        return Hex.encodeHexString(bytes);
    }

    public static String encodeHex(long value) {
        long tmpL = value;
        int bytes = 0;
        while (bytes < Long.SIZE && tmpL > 0) {
            tmpL = tmpL >> 8;
            bytes++;
        }
        return encodeHex(value, bytes);
    }

    public static String encodeHex(long value, int bytes) {
        return encodeHex(Conversion.longToByteArray(value, 0, new byte[bytes], 0, bytes));
    }

    // -----
    // --- Hex decode:          String -> byte[]
    // -

    /**
     * converting a hexadecimal format String to corresponding byte[]
     * @param hex the hexadecimal format String
     * @return corresponding byte[]
     */
    public static byte[] decodeHex(String hex) {
        if (StringUtils.isBlank(hex))
            return null;
        byte[] ret;
        try {
            ret = Hex.decodeHex(hex.toCharArray());
        } catch (DecoderException e) {
            // never thrown if target hex has been generated by any HexUtility
            throw new RuntimeException(e);
        }
        return ret;
    }

    public static InputStream decodeHexToInputStream(String hex) {
        if (StringUtils.isBlank(hex))
            return null;
        byte[] content = HexUtils.decodeHex(hex);
        return new ByteArrayInputStream(content);
    }

    // -----
    // --- Random hex generation
    // -

    public static String randomHex(int length) {
        StringBuilder buf = new StringBuilder();
        for (int i = 0; i < length; i++) {
            buf.append(Long.toHexString((long) (Math.random() * 16)));
        }
        return buf.toString();
    }

}