Java Byte Array to Base64 bytesToBase64(byte[] bytes, int length)

Description

Converts a maximum of three bytes to 4 Base64 characters

License

Open Source License

Declaration

private static String bytesToBase64(byte[] bytes, int length) 

Method Source Code

//package com.java2s;
/**/*w ww.  java 2s.  c  om*/
* 
* Copyright (C) 2004-2008 FhG Fokus
*
* This file is part of the FhG Fokus UPnP stack - an open source UPnP implementation
* with some additional features
*
* You can redistribute the FhG Fokus UPnP stack and/or modify it
* under the terms of the GNU General Public License Version 3 as published by
* the Free Software Foundation.
*
* For a license to use the FhG Fokus UPnP stack software under conditions
* other than those described here, or to purchase support for this
* software, please contact Fraunhofer FOKUS by e-mail at the following
* addresses:
*   upnpstack@fokus.fraunhofer.de
*
* The FhG Fokus UPnP stack 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/>
* or write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/

public class Main {
    /** Converts a maximum of three bytes to 4 Base64 characters */
    private static String bytesToBase64(byte[] bytes, int length) {
        String result = "";
        if (length == 3) {
            result += bitsToBase64((byte) ((bytes[0] & 0xFC) >> 2));
            result += bitsToBase64((byte) ((bytes[0] & 0x03) << 4 | (bytes[1] & 0xF0) >> 4));
            result += bitsToBase64((byte) ((bytes[1] & 0x0F) << 2 | (bytes[2] & 0xC0) >> 6));
            result += bitsToBase64((byte) (bytes[2] & 0x3F));
        }
        if (length == 2) {
            result += bitsToBase64((byte) ((bytes[0] & 0xFC) >> 2));
            result += bitsToBase64((byte) ((bytes[0] & 0x03) << 4 | (bytes[1] & 0xF0) >> 4));
            result += bitsToBase64((byte) ((bytes[1] & 0x0F) << 2));
            result += '=';
        }
        if (length == 1) {
            result += bitsToBase64((byte) ((bytes[0] & 0xFC) >> 2));
            result += bitsToBase64((byte) ((bytes[0] & 0x03) << 4));
            result += '=';
            result += '=';
        }
        return result;
    }

    /** Converts a 6-bit value to the corresponding Base64 char */
    private static char bitsToBase64(byte data) {
        if (data >= 0 && data < 26) {
            return (char) (data + 'A');
        }
        if (data >= 26 && data < 52) {
            return (char) (data - 26 + 'a');
        }
        if (data >= 52 && data < 62) {
            return (char) (data - 52 + '0');
        }
        if (data == 62) {
            return '+';
        }
        if (data == 63) {
            return '/';
        }
        return (char) 0;
    }
}

Related

1. byteArrayToBase64(byte[] a)
2. bytesToBase64(byte[] bytes)
3. byteToBase64(byte[] data)