/*************************************************************************
 *                                                                       *
 *  CERT-CVC: EAC 1.11 Card Verifiable Certificate Library               * 
 *                                                                       *
 *  This software is free software; you can redistribute it and/or       *
 *  modify it under the terms of the GNU Lesser General Public           *
 *  License as published by the Free Software Foundation; either         *
 *  version 2.1 of the License, or any later version.                    *
 *                                                                       *
 *  See terms of license at gnu.org.                                     *
 *                                                                       *
 *************************************************************************/
package org.ejbca.cvc.util;

/**
 * Utility for mapping between byte values and hex codes
 * 
 * @author Keijo Kurkinen, Swedish National Police Board
 * @version $Id: StringConverter.java 9074 2010-05-20 08:06:39Z anatom $
 */
public final class StringConverter {

    private static final char HEXCHAR[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E',
	    'F' };

    private static final String HEXINDEX = "0123456789abcdef          ABCDEF";

    private StringConverter() {
    }

    public static byte[] hexToByte(final String s) {
	final int l = s.length() / 2;
	byte data[] = new byte[l];
	int j = 0;

	for (int i = 0; i < l; i++) {
	    char c = s.charAt(j++);
	    int n, b;

	    n = HEXINDEX.indexOf(c);
	    b = (n & 0xf) << 4;
	    c = s.charAt(j++);
	    n = HEXINDEX.indexOf(c);
	    b += (n & 0xf);
	    data[i] = (byte) b;
	}
	return data;
    }

    public static String byteToHex(final byte b[]) {
	return byteToHex(b, null);
    }

    public static String byteToHex(final byte b[], final String sep) {
	final int len = b.length;
	final StringBuffer sb = new StringBuffer();

	for (int i = 0; i < len; i++) {
	    sb.append(byteToHex(b[i]));
	    if (sep != null && (i + 1) < len) {
		sb.append(sep);
	    }
	}
	return sb.toString();
    }

    public static String byteToHex(final byte b) {
	final int c = ((int) b) & 0xff;
	final char c1 = HEXCHAR[c >> 4 & 0xF];
	final char c2 = HEXCHAR[c & 0xF];

	return Character.toString(c1) + c2;
    }

}