HexEncode.java

/*
Copyright (C) 2011 The University of Michigan

This program 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.

This program 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.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

Please send inquiries to powertutor@umich.edu
*/

package edu.umich.PowerTutor.util;

public class HexEncode {
  public static String encode(byte[] bytes) {
    StringBuilder bld = new StringBuilder();
    for(int i = 0; i < bytes.length; i++) {
      bld.append((char)('a' + (bytes[i] >> 4 & 0xF)));
      bld.append((char)('a' + (bytes[i] & 0xF)));
    }
    return bld.toString();
  }

  public static byte[] decode(String dat) {
    int N = dat.length() / 2;
    byte[] ret = new byte[N];
    for(int i = 0; i < N; i++) {
      ret[i] = (byte)(dat.charAt(2 * i) - 'a' << 4 |
                      dat.charAt(2 * i + 1) - 'a');
    }
    return ret;
  }
}