Class Base64 can be used for base64-encoding a byte array and/or for base64-decoding a base64-string. : Base64 « Date Type « Android

1. Android
2. Date Type
3. Base64

Class Base64 can be used for base64-encoding a byte array and/or for base64-decoding a base64-string.

  
/*
 * Copyright (C) 2005 Luca Veltri - University of Parma - Italy
 * 
 * This file is part of MjSip (http://www.mjsip.org)
 * 
 * MjSip 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 2 of the License, or
 * (at your option) any later version.
 * 
 * MjSip 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 MjSip; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * 
 * Author(s):
 * Luca Veltri (luca.veltri@unipr.it)
 */

//package org.zoolu.tools;

/**
 * Class Base64 can be used for base64-encoding a byte array and/or for
 * base64-decoding a base64-string.
 * 
 * @author Camilla Ferramola, Univeristy of Parma, Italy - 2004
 */
class Base64 {
  private static final String base64codes = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  private static int[] aux = new int[4];

  /** Base64 encoder */
  public static String encode(byte[] input) {

    String stringacod = "";
    byte[] bin = new byte[3];

    int iter = (input.length) / 3;
    int nzero = (input.length) % 3;
    int i = 0;

    for (i = 0; i < iter; i++) {
      bin[0] = input[i * 3];
      bin[1] = input[i * 3 + 1];
      bin[2] = input[i * 3 + 2];

      aux[0] = ((bin[0] >>> 2) & 63);
      aux[1] = ((bin[0] & 3) << 4) + ((bin[1] >>> 4) & 15);
      aux[2] = ((bin[1] & 15) << 2) + ((bin[2] >>> 6) & 3);
      aux[3] = (bin[2] & 63);

      // uso gli interi memorizzati in aux[] come indice della stringa
      // base64codes
      // System.out.println("aux[0]="+aux[0]+" aux[1]="+aux[1]);
      stringacod = stringacod + base64codes.charAt(aux[0])
          + base64codes.charAt(aux[1]) + base64codes.charAt(aux[2])
          + base64codes.charAt(aux[3]);
    }

    if (i == iter) {
      if (nzero == 0) {
      } else if (nzero == 1) { // l'ultimo pacchetto da analizzare ha 8
        // bit
        // quindi ottengo due caratteri in base64 e due caratteri
        // padding "="
        aux[0] = ((input[iter * 3] >>> 2) & 63);
        aux[1] = (input[iter * 3] & 3) << 4;

        stringacod = stringacod + base64codes.charAt(aux[0])
            + base64codes.charAt(aux[1]) + "==";
      } else if (nzero == 2) { // l'ultimo pacchetto da analizzare ha
        // 16 bit quindi ottengo
        // tre caratteri in base 64 e uno di padding "="
        aux[0] = ((input[iter * 3] >>> 2) & 63);
        aux[1] = ((input[iter * 3] & 3) << 4)
            + ((input[iter * 3 + 1] >>> 4) & 15);
        aux[2] = (input[iter * 3 + 1] & 15) << 2;

        stringacod = stringacod + base64codes.charAt(aux[0])
            + base64codes.charAt(aux[1])
            + base64codes.charAt(aux[2]) + "=";
      }
    }

    return stringacod;

  }

  /** Base64 decoder */
  public static byte[] decode(String stringacod) {
    // tolgo gli eventuali "=" alla fine della stringa
    int uguale = stringacod.indexOf("=");
    if (uguale != -1)
      stringacod = stringacod.substring(0, uguale);

    int[] bin = new int[3];
    int iter = (stringacod.length()) / 4;
    int resto = (stringacod.length()) % 4;

    int nzero = 0;
    if (resto != 0)
      nzero = 1;
    byte[] output = new byte[iter * 3 + nzero * (resto - 1)];

    int i = 0;
    for (i = 0; i < iter; i++) {
      aux[0] = base64codes.indexOf(stringacod.charAt(i * 4));
      aux[1] = base64codes.indexOf(stringacod.charAt(i * 4 + 1));
      aux[2] = base64codes.indexOf(stringacod.charAt(i * 4 + 2));
      aux[3] = base64codes.indexOf(stringacod.charAt(i * 4 + 3));

      bin[0] = (aux[0] << 2) + (aux[1] >>> 4);
      bin[1] = (aux[1] % 16 << 4) + (aux[2] >>> 2);
      bin[2] = (aux[2] % 4 << 6) + aux[3];

      output[i * 3] = (byte) bin[0];
      output[i * 3 + 1] = (byte) bin[1];
      output[i * 3 + 2] = (byte) bin[2];
    }

    if (i == iter) {
      // per come e costruita la codifica a base64
      // togliendo gli eventuali caratteri "=" di padding
      // il resto puo essere 0, 2 o 3
      if (resto == 0) {
      }
      if (resto == 2) {
        aux[0] = base64codes.indexOf(stringacod.charAt(i * 4));
        aux[1] = base64codes.indexOf(stringacod.charAt(i * 4 + 1));

        bin[0] = (aux[0] << 2) + (aux[1] >>> 4);

        output[i * 3] = (byte) bin[0];
      }

      if (resto == 3) {
        aux[0] = base64codes.indexOf(stringacod.charAt(i * 4));
        aux[1] = base64codes.indexOf(stringacod.charAt(i * 4 + 1));
        aux[2] = base64codes.indexOf(stringacod.charAt(i * 4 + 2));

        bin[0] = (aux[0] << 2) + (aux[1] >>> 4);
        bin[1] = (aux[1] % 16 << 4) + (aux[2] >>> 2);

        output[i * 3] = (byte) bin[0];
        output[i * 3 + 1] = (byte) bin[1];
      }
    }
    return output;
  }

  // ******************************* MAIN *******************************

  public static void main(String[] args) {
    String messaggio = args[0];
    byte[] bmess = messaggio.getBytes();
    String mess64 = encode(bmess);
    System.out.println("messaggio codificato: " + mess64);
    byte[] decodificato = decode(mess64);
    String strdecodificato = "";
    try {
      strdecodificato = new String(decodificato, "ISO-8859-1");
    } catch (Exception e) {
      e.printStackTrace();
    }
    System.out.println("messaggio decodificato e: " + strdecodificato);
  }
}

   
    
  

Related examples in the same category