Main.java Source code

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Here is the source code for Main.java

Source

//package com.java2s;
// and/or modify it under the terms of the GNU General Public License 

import java.io.UnsupportedEncodingException;

public class Main {
    /**
     * Value of Hex A in decimal.
     */
    static final int HEX_A_DECIMAL_VALUE = 10;
    /**
     * Half a byte.
     */
    static final int NIBBLE = 4;

    /**
     * Convert string to byte array.
     *
     * @param value Hex string.
     * @return byte array.
     */
    public static byte[] hexToBytes(final String value) {
        byte[] buffer = new byte[value.length() / 2];
        int lastValue = -1;
        int index = 0;
        try {
            for (byte ch : value.getBytes("ASCII")) {
                if (ch >= '0' && ch < 'g') {
                    if (lastValue == -1) {
                        lastValue = getValue(ch);
                    } else if (lastValue != -1) {
                        buffer[index] = (byte) (lastValue << NIBBLE | getValue(ch));
                        lastValue = -1;
                        ++index;
                    }
                } else if (lastValue != -1) {
                    buffer[index] = getValue(ch);
                    lastValue = -1;
                    ++index;
                }
            }
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e.getMessage());
        }
        byte[] tmp = new byte[index];
        System.arraycopy(buffer, 0, tmp, 0, index);
        return tmp;
    }

    /**
     * Convert char hex value to byte value.
     *
     * @param c Character to convert hex.
     * @return Byte value of hex char value.
     */
    private static byte getValue(final byte c) {
        byte value;
        // Id char.
        if (c > '9') {
            if (c > 'Z') {
                value = (byte) (c - 'a');
            } else {
                value = (byte) (c - 'A');
            }
            value += HEX_A_DECIMAL_VALUE;
        } else {
            // If number.
            value = (byte) (c - '0');
        }
        return value;
    }
}