Mega Code Archive
Class Base64 can be used for base64-encoding a byte array andor for base64-decoding a base64-string
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/*
* 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);
}
}
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