/**
 * JWAP - A Java Implementation of the WAP Protocols
 * Copyright (C) 2001-2004 Niko Bender
 *
 * This library 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 (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package net.sourceforge.jwap.util;



/**
 * This class contains various static utility methods.
 *
 * @author Michel Marti
 *
 */
public class Utils {
    /**
     * Construct a String containing a hex-dump of a byte array
     * @param bytes the data to dump
     * @return a string containing the hexdump
     */
    public static String hexDump(byte[] bytes) {
        return hexDump(null, bytes);
    }

    /**
     * Construct a String containing a hex-dump of a byte array
     * @param label the label of the hexdump or null
     * @param bytes the data to dump
     * @return a string containing the hexdump
     */
    public static String hexDump(String label, byte[] bytes) {
        final int modulo = 16;
        final int brk = modulo / 2;
        int indent = (label == null) ? 0 : label.length();

        StringBuffer sb = new StringBuffer(indent + 1);

        while (indent > 0) {
            sb.append(" ");
            indent--;
        }

        String ind = sb.toString();

        if (bytes == null) {
            return null;
        }

        sb = new StringBuffer(bytes.length * 4);

        StringBuffer cb = new StringBuffer(16);
        boolean nl = true;
        int i = 0;

        for (i = 1; i <= bytes.length; i++) {
            // start of line?
            if (nl) {
                nl = false;

                if (i > 1) {
                    sb.append(ind);
                } else if (label != null) {
                    sb.append(label);
                }

                String ha = Integer.toHexString(i - 1);

                for (int j = ha.length(); j <= 8; j++) {
                    sb.append("0");
                }

                sb.append(ha).append(" ");
            }

            sb.append(" ");

            int c = (bytes[i - 1] & 0xFF);
            String hx = Integer.toHexString(c).toUpperCase();

            if (hx.length() == 1) {
                sb.append("0");
            }

            sb.append(hx);
            cb.append((c < 0x21 || c > 0x7e )? '.' : (char) (c));

            if ((i % brk) == 0) {
                sb.append(" ");
            }

            if ((i % modulo) == 0) {
                sb.append("|").append(cb).append("|\n");
                nl = true;
                cb = new StringBuffer(16);
            }
        }

        int mod = i % modulo;
        if (mod != 1) {
            if(mod==0) {
              mod=modulo;
            }
            while (mod <= modulo) {
                sb.append("   ");

                if ((mod % brk) == 0) {
                    sb.append(" ");
                }

                mod++;
            }

            sb.append("|").append(cb).append("|\n");
        }

        return sb.toString();
    }
}