| /* |
| * Copyright (c) 1995, 1997, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code 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 |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package sun.misc; |
| |
| import java.io.OutputStream; |
| import java.io.InputStream; |
| import java.io.PrintStream; |
| import java.io.IOException; |
| |
| /** |
| * This class implements a BASE64 Character encoder as specified in RFC1521. |
| * This RFC is part of the MIME specification as published by the Internet |
| * Engineering Task Force (IETF). Unlike some other encoding schemes there |
| * is nothing in this encoding that indicates |
| * where a buffer starts or ends. |
| * |
| * This means that the encoded text will simply start with the first line |
| * of encoded text and end with the last line of encoded text. |
| * |
| * @author Chuck McManis |
| * @see CharacterEncoder |
| * @see BASE64Decoder |
| */ |
| |
| public class BASE64Encoder extends CharacterEncoder { |
| |
| /** this class encodes three bytes per atom. */ |
| protected int bytesPerAtom() { |
| return (3); |
| } |
| |
| /** |
| * this class encodes 57 bytes per line. This results in a maximum |
| * of 57/3 * 4 or 76 characters per output line. Not counting the |
| * line termination. |
| */ |
| protected int bytesPerLine() { |
| return (57); |
| } |
| |
| /** This array maps the characters to their 6 bit values */ |
| private final static char pem_array[] = { |
| // 0 1 2 3 4 5 6 7 |
| 'A','B','C','D','E','F','G','H', // 0 |
| 'I','J','K','L','M','N','O','P', // 1 |
| 'Q','R','S','T','U','V','W','X', // 2 |
| 'Y','Z','a','b','c','d','e','f', // 3 |
| 'g','h','i','j','k','l','m','n', // 4 |
| 'o','p','q','r','s','t','u','v', // 5 |
| 'w','x','y','z','0','1','2','3', // 6 |
| '4','5','6','7','8','9','+','/' // 7 |
| }; |
| |
| /** |
| * encodeAtom - Take three bytes of input and encode it as 4 |
| * printable characters. Note that if the length in len is less |
| * than three is encodes either one or two '=' signs to indicate |
| * padding characters. |
| */ |
| protected void encodeAtom(OutputStream outStream, byte data[], int offset, int len) |
| throws IOException { |
| byte a, b, c; |
| |
| if (len == 1) { |
| a = data[offset]; |
| b = 0; |
| c = 0; |
| outStream.write(pem_array[(a >>> 2) & 0x3F]); |
| outStream.write(pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)]); |
| outStream.write('='); |
| outStream.write('='); |
| } else if (len == 2) { |
| a = data[offset]; |
| b = data[offset+1]; |
| c = 0; |
| outStream.write(pem_array[(a >>> 2) & 0x3F]); |
| outStream.write(pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)]); |
| outStream.write(pem_array[((b << 2) & 0x3c) + ((c >>> 6) & 0x3)]); |
| outStream.write('='); |
| } else { |
| a = data[offset]; |
| b = data[offset+1]; |
| c = data[offset+2]; |
| outStream.write(pem_array[(a >>> 2) & 0x3F]); |
| outStream.write(pem_array[((a << 4) & 0x30) + ((b >>> 4) & 0xf)]); |
| outStream.write(pem_array[((b << 2) & 0x3c) + ((c >>> 6) & 0x3)]); |
| outStream.write(pem_array[c & 0x3F]); |
| } |
| } |
| } |