1 /*

     2  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 /*

    27  * @(#)BASE64EncoderStream.java       1.6 02/03/27

    28  */

    29 

    30 

    31 

    32 package com.sun.xml.internal.messaging.saaj.packaging.mime.util;

    33 

    34 import java.io.*;

    35 

    36 /**

    37  * This class implements a BASE64 Encoder. It is implemented as

    38  * a FilterOutputStream, so one can just wrap this class around

    39  * any output stream and write bytes into this filter. The Encoding

    40  * is done as the bytes are written out.

    41  *

    42  * @author John Mani

    43  * @author Bill Shannon

    44  */

    45 

    46 public class BASE64EncoderStream extends FilterOutputStream {

    47     private byte[] buffer;      // cache of bytes that are yet to be encoded

    48     private int bufsize = 0;    // size of the cache

    49     private int count = 0;      // number of bytes that have been output

    50     private int bytesPerLine;   // number of bytes per line

    51 

    52     /**

    53      * Create a BASE64 encoder that encodes the specified input stream

    54      * @param out        the output stream

    55      * @param bytesPerLine  number of bytes per line. The encoder inserts

    56      *                   a CRLF sequence after the specified number of bytes

    57      */

    58     public BASE64EncoderStream(OutputStream out, int bytesPerLine) {

    59         super(out);

    60         buffer = new byte[3];

    61         this.bytesPerLine = bytesPerLine;

    62     }

    63 

    64     /**

    65      * Create a BASE64 encoder that encodes the specified input stream.

    66      * Inserts the CRLF sequence after outputting 76 bytes.

    67      * @param out        the output stream

    68      */

    69     public BASE64EncoderStream(OutputStream out) {

    70         this(out, 76);

    71     }

    72 

    73     /**

    74      * Encodes <code>len</code> bytes from the specified

    75      * <code>byte</code> array starting at offset <code>off</code> to

    76      * this output stream.

    77      *

    78      * @param      b     the data.

    79      * @param      off   the start offset in the data.

    80      * @param      len   the number of bytes to write.

    81      * @exception  IOException  if an I/O error occurs.

    82      */

    83     public void write(byte[] b, int off, int len) throws IOException {

    84         for (int i = 0; i < len; i++)

    85             write(b[off + i]);

    86     }

    87 

    88     /**

    89      * Encodes <code>b.length</code> bytes to this output stream.

    90      * @param      b   the data to be written.

    91      * @exception  IOException  if an I/O error occurs.

    92      */

    93     public void write(byte[] b) throws IOException {

    94         write(b, 0, b.length);

    95     }

    96 

    97     /**

    98      * Encodes the specified <code>byte</code> to this output stream.

    99      * @param      c   the <code>byte</code>.

   100      * @exception  IOException  if an I/O error occurs.

   101      */

   102     public void write(int c) throws IOException {

   103         buffer[bufsize++] = (byte)c;

   104         if (bufsize == 3) { // Encoding unit = 3 bytes

   105             encode();

   106             bufsize = 0;

   107         }

   108     }

   109 

   110     /**

   111      * Flushes this output stream and forces any buffered output bytes

   112      * to be encoded out to the stream.

   113      * @exception  IOException  if an I/O error occurs.

   114      */

   115     public void flush() throws IOException {

   116         if (bufsize > 0) { // If there's unencoded characters in the buffer ..

   117             encode();      // .. encode them

   118             bufsize = 0;

   119         }

   120         out.flush();

   121     }

   122 

   123     /**

   124      * Forces any buffered output bytes to be encoded out to the stream

   125      * and closes this output stream

   126      */

   127     public void close() throws IOException {

   128         flush();

   129         out.close();

   130     }

   131 

   132     /** This array maps the characters to their 6 bit values */

   133     private final static char pem_array[] = {

   134         'A','B','C','D','E','F','G','H', // 0

   135         'I','J','K','L','M','N','O','P', // 1

   136         'Q','R','S','T','U','V','W','X', // 2

   137         'Y','Z','a','b','c','d','e','f', // 3

   138         'g','h','i','j','k','l','m','n', // 4

   139         'o','p','q','r','s','t','u','v', // 5

   140         'w','x','y','z','0','1','2','3', // 6

   141         '4','5','6','7','8','9','+','/'  // 7

   142     };

   143 

   144     private void encode() throws IOException {

   145         // If writing out this encoded unit will cause overflow,

   146         // start a new line.

   147         if (count + 4 > bytesPerLine) {

   148             out.write('\r');

   149             out.write('\n');

   150             count = 0;

   151         }

   152 

   153         byte a, b, c;

   154         if (bufsize == 1) {

   155             a = buffer[0];

   156             b = 0;

   157             c = 0;

   158             out.write(pem_array[(a >>> 2) & 0x3F]);

   159             out.write(pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)]);

   160             out.write('='); // pad character

   161             out.write('='); // pad character

   162         } else if (bufsize == 2) {

   163             a = buffer[0];

   164             b = buffer[1];

   165             c = 0;

   166             out.write(pem_array[(a >>> 2) & 0x3F]);

   167             out.write(pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)]);

   168             out.write(pem_array[((b << 2) & 0x3c) + ((c >>> 6) & 0x3)]);

   169             out.write('='); // pad character

   170         } else {

   171             a = buffer[0];

   172             b = buffer[1];

   173             c = buffer[2];

   174             out.write(pem_array[(a >>> 2) & 0x3F]);

   175             out.write(pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)]);

   176             out.write(pem_array[((b << 2) & 0x3c) + ((c >>> 6) & 0x3)]);

   177             out.write(pem_array[c & 0x3F]);

   178         }

   179 

   180         // increment count

   181         count += 4;

   182     }

   183 

   184     /**

   185      * Base64 encode a byte array.  No line breaks are inserted.

   186      * This method is suitable for short strings, such as those

   187      * in the IMAP AUTHENTICATE protocol, but not to encode the

   188      * entire content of a MIME part.

   189      */

   190     public static byte[] encode(byte[] inbuf) {

   191         if (inbuf.length == 0)

   192             return inbuf;

   193         byte[] outbuf = new byte[((inbuf.length + 2) / 3) * 4];

   194         int inpos = 0, outpos = 0;

   195         int size = inbuf.length;

   196         while (size > 0) {

   197             byte a, b, c;

   198             if (size == 1) {

   199                 a = inbuf[inpos++];

   200                 b = 0;

   201                 c = 0;

   202                 outbuf[outpos++] = (byte)pem_array[(a >>> 2) & 0x3F];

   203                 outbuf[outpos++] =

   204                         (byte)pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)];

   205                 outbuf[outpos++] = (byte)'=';  // pad character

   206                 outbuf[outpos++] = (byte)'=';  // pad character

   207             } else if (size == 2) {

   208                 a = inbuf[inpos++];

   209                 b = inbuf[inpos++];

   210                 c = 0;

   211                 outbuf[outpos++] = (byte)pem_array[(a >>> 2) & 0x3F];

   212                 outbuf[outpos++] =

   213                         (byte)pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)];

   214                 outbuf[outpos++] =

   215                         (byte)pem_array[((b << 2) & 0x3c) + ((c >>> 6) & 0x3)];

   216                 outbuf[outpos++] = (byte)'=';  // pad character

   217             } else {

   218                 a = inbuf[inpos++];

   219                 b = inbuf[inpos++];

   220                 c = inbuf[inpos++];

   221                 outbuf[outpos++] = (byte)pem_array[(a >>> 2) & 0x3F];

   222                 outbuf[outpos++] =

   223                         (byte)pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)];

   224                 outbuf[outpos++] =

   225                         (byte)pem_array[((b << 2) & 0x3c) + ((c >>> 6) & 0x3)];

   226                 outbuf[outpos++] = (byte)pem_array[c & 0x3F];

   227             }

   228             size -= 3;

   229         }

   230         return outbuf;

   231     }

   232 

   233     /*** begin TEST program

   234     public static void main(String argv[]) throws Exception {

   235         FileInputStream infile = new FileInputStream(argv[0]);

   236         BASE64EncoderStream encoder = new BASE64EncoderStream(System.out);

   237         int c;

   238 

   239         while ((c = infile.read()) != -1)

   240             encoder.write(c);

   241         encoder.close();

   242     }

   243     *** end TEST program **/

   244 }