Base64


1    /*
2    * Copyright 2001-2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.axis2.attachments;
17  
18  import java.io.IOException  ;
19  import java.io.OutputStream  ;
20  import java.io.Writer  ;
21  
22  /**
23   * @author TAMURA Kent &lt;kent@trl.ibm.co.jp&gt;
24   */
25  public class Base64 {
26      private static final char[] S_BASE64CHAR = { 'A', 'B', 'C', 'D', 'E', 'F',
27              'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S',
28              'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
29              'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's',
30              't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5',
31              '6', '7', '8', '9', '+', '/' };
32  
33      private static final char S_BASE64PAD = '=';
34  
35      private static final byte[] S_DECODETABLE = new byte[128];
36  
37      static {
38          for (int i = 0; i < S_DECODETABLE.length; i++)
39              S_DECODETABLE[i] = Byte.MAX_VALUE; // 127
40          for (int i = 0; i < S_BASE64CHAR.length; i++)
41              // 0 to 63
42              S_DECODETABLE[S_BASE64CHAR[i]] = (byte) i;
43      }
44  
45      private static int decode0(char[] ibuf, byte[] obuf, int wp) {
46          int outlen = 3;
47          if (ibuf[3] == S_BASE64PAD)
48              outlen = 2;
49          if (ibuf[2] == S_BASE64PAD)
50              outlen = 1;
51          int b0 = S_DECODETABLE[ibuf[0]];
52          int b1 = S_DECODETABLE[ibuf[1]];
53          int b2 = S_DECODETABLE[ibuf[2]];
54          int b3 = S_DECODETABLE[ibuf[3]];
55          switch (outlen) {
56          case 1:
57              obuf[wp] = (byte) (b0 << 2 & 0xfc | b1 >> 4 & 0x3);
58              return 1;
59          case 2:
60              obuf[wp++] = (byte) (b0 << 2 & 0xfc | b1 >> 4 & 0x3);
61              obuf[wp] = (byte) (b1 << 4 & 0xf0 | b2 >> 2 & 0xf);
62              return 2;
63          case 3:
64              obuf[wp++] = (byte) (b0 << 2 & 0xfc | b1 >> 4 & 0x3);
65              obuf[wp++] = (byte) (b1 << 4 & 0xf0 | b2 >> 2 & 0xf);
66              obuf[wp] = (byte) (b2 << 6 & 0xc0 | b3 & 0x3f);
67              return 3;
68          default:
69              throw new RuntimeException  ("internalError00");
70          }
71      }
72  
73      /**
74       *  
75       */
76      public static byte[] decode(char[] data, int off, int len) {
77          char[] ibuf = new char[4];
78          int ibufcount = 0;
79          byte[] obuf = new byte[len / 4 * 3 + 3];
80          int obufcount = 0;
81          for (int i = off; i < off + len; i++) {
82              char ch = data[i];
83              if (ch == S_BASE64PAD || ch < S_DECODETABLE.length
84                      && S_DECODETABLE[ch] != Byte.MAX_VALUE) {
85                  ibuf[ibufcount++] = ch;
86                  if (ibufcount == ibuf.length) {
87                      ibufcount = 0;
88                      obufcount += decode0(ibuf, obuf, obufcount);
89                  }
90              }
91          }
92          if (obufcount == obuf.length)
93              return obuf;
94          byte[] ret = new byte[obufcount];
95          System.arraycopy(obuf, 0, ret, 0, obufcount);
96          return ret;
97      }
98  
99      /**
100      *  
101      */
102     public static byte[] decode(String   data) {
103         char[] ibuf = new char[4];
104         int ibufcount = 0;
105         byte[] obuf = new byte[data.length() / 4 * 3 + 3];
106         int obufcount = 0;
107         for (int i = 0; i < data.length(); i++) {
108             char ch = data.charAt(i);
109             if (ch == S_BASE64PAD || ch < S_DECODETABLE.length
110                     && S_DECODETABLE[ch] != Byte.MAX_VALUE) {
111                 ibuf[ibufcount++] = ch;
112                 if (ibufcount == ibuf.length) {
113                     ibufcount = 0;
114                     obufcount += decode0(ibuf, obuf, obufcount);
115                 }
116             }
117         }
118         if (obufcount == obuf.length)
119             return obuf;
120         byte[] ret = new byte[obufcount];
121         System.arraycopy(obuf, 0, ret, 0, obufcount);
122         return ret;
123     }
124 
125     /**
126      *  
127      */
128     public static void decode(char[] data, int off, int len,
129             OutputStream   ostream) throws IOException   {
130         char[] ibuf = new char[4];
131         int ibufcount = 0;
132         byte[] obuf = new byte[3];
133         for (int i = off; i < off + len; i++) {
134             char ch = data[i];
135             if (ch == S_BASE64PAD || ch < S_DECODETABLE.length
136                     && S_DECODETABLE[ch] != Byte.MAX_VALUE) {
137                 ibuf[ibufcount++] = ch;
138                 if (ibufcount == ibuf.length) {
139                     ibufcount = 0;
140                     int obufcount = decode0(ibuf, obuf, 0);
141                     ostream.write(obuf, 0, obufcount);
142                 }
143             }
144         }
145     }
146 
147     /**
148      *  
149      */
150     public static void decode(String   data, OutputStream   ostream)
151             throws IOException   {
152         char[] ibuf = new char[4];
153         int ibufcount = 0;
154         byte[] obuf = new byte[3];
155         for (int i = 0; i < data.length(); i++) {
156             char ch = data.charAt(i);
157             if (ch == S_BASE64PAD || ch < S_DECODETABLE.length
158                     && S_DECODETABLE[ch] != Byte.MAX_VALUE) {
159                 ibuf[ibufcount++] = ch;
160                 if (ibufcount == ibuf.length) {
161                     ibufcount = 0;
162                     int obufcount = decode0(ibuf, obuf, 0);
163                     ostream.write(obuf, 0, obufcount);
164                 }
165             }
166         }
167     }
168 
169     /**
170      * Returns base64 representation of specified byte array.
171      */
172     public static String   encode(byte[] data) {
173         return encode(data, 0, data.length);
174     }
175 
176     /**
177      * Returns base64 representation of specified byte array.
178      */
179     public static String   encode(byte[] data, int off, int len) {
180         if (len <= 0)
181             return "";
182         char[] out = new char[len / 3 * 4 + 4];
183         int rindex = off;
184         int windex = 0;
185         int rest = len - off;
186         while (rest >= 3) {
187             int i = ((data[rindex] & 0xff) << 16)
188                     + ((data[rindex + 1] & 0xff) << 8)
189                     + (data[rindex + 2] & 0xff);
190             out[windex++] = S_BASE64CHAR[i >> 18];
191             out[windex++] = S_BASE64CHAR[(i >> 12) & 0x3f];
192             out[windex++] = S_BASE64CHAR[(i >> 6) & 0x3f];
193             out[windex++] = S_BASE64CHAR[i & 0x3f];
194             rindex += 3;
195             rest -= 3;
196         }
197         if (rest == 1) {
198             int i = data[rindex] & 0xff;
199             out[windex++] = S_BASE64CHAR[i >> 2];
200             out[windex++] = S_BASE64CHAR[(i << 4) & 0x3f];
201             out[windex++] = S_BASE64PAD;
202             out[windex++] = S_BASE64PAD;
203         } else if (rest == 2) {
204             int i = ((data[rindex] & 0xff) << 8) + (data[rindex + 1] & 0xff);
205             out[windex++] = S_BASE64CHAR[i >> 10];
206             out[windex++] = S_BASE64CHAR[(i >> 4) & 0x3f];
207             out[windex++] = S_BASE64CHAR[(i << 2) & 0x3f];
208             out[windex++] = S_BASE64PAD;
209         }
210         return new String  (out, 0, windex);
211     }
212 
213     /**
214      * Outputs base64 representation of the specified byte array to a byte
215      * stream.
216      */
217     public static void encode(byte[] data, int off, int len,
218             OutputStream   ostream) throws IOException   {
219         if (len <= 0)
220             return;
221         byte[] out = new byte[4];
222         int rindex = off;
223         int rest = len - off;
224         while (rest >= 3) {
225             int i = ((data[rindex] & 0xff) << 16)
226                     + ((data[rindex + 1] & 0xff) << 8)
227                     + (data[rindex + 2] & 0xff);
228             out[0] = (byte) S_BASE64CHAR[i >> 18];
229             out[1] = (byte) S_BASE64CHAR[(i >> 12) & 0x3f];
230             out[2] = (byte) S_BASE64CHAR[(i >> 6) & 0x3f];
231             out[3] = (byte) S_BASE64CHAR[i & 0x3f];
232             ostream.write(out, 0, 4);
233             rindex += 3;
234             rest -= 3;
235         }
236         if (rest == 1) {
237             int i = data[rindex] & 0xff;
238             out[0] = (byte) S_BASE64CHAR[i >> 2];
239             out[1] = (byte) S_BASE64CHAR[(i << 4) & 0x3f];
240             out[2] = (byte) S_BASE64PAD;
241             out[3] = (byte) S_BASE64PAD;
242             ostream.write(out, 0, 4);
243         } else if (rest == 2) {
244             int i = ((data[rindex] & 0xff) << 8) + (data[rindex + 1] & 0xff);
245             out[0] = (byte) S_BASE64CHAR[i >> 10];
246             out[1] = (byte) S_BASE64CHAR[(i >> 4) & 0x3f];
247             out[2] = (byte) S_BASE64CHAR[(i << 2) & 0x3f];
248             out[3] = (byte) S_BASE64PAD;
249             ostream.write(out, 0, 4);
250         }
251     }
252 
253     /**
254      * Outputs base64 representation of the specified byte array to a character
255      * stream.
256      */
257     public static void encode(byte[] data, int off, int len, Writer   writer)
258             throws IOException   {
259         if (len <= 0)
260             return;
261         char[] out = new char[4];
262         int rindex = off;
263         int rest = len - off;
264         int output = 0;
265         while (rest >= 3) {
266             int i = ((data[rindex] & 0xff) << 16)
267                     + ((data[rindex + 1] & 0xff) << 8)
268                     + (data[rindex + 2] & 0xff);
269             out[0] = S_BASE64CHAR[i >> 18];
270             out[1] = S_BASE64CHAR[(i >> 12) & 0x3f];
271             out[2] = S_BASE64CHAR[(i >> 6) & 0x3f];
272             out[3] = S_BASE64CHAR[i & 0x3f];
273             writer.write(out, 0, 4);
274             rindex += 3;
275             rest -= 3;
276             output += 4;
277             if (output % 76 == 0)
278                 writer.write("\n");
279         }
280         if (rest == 1) {
281             int i = data[rindex] & 0xff;
282             out[0] = S_BASE64CHAR[i >> 2];
283             out[1] = S_BASE64CHAR[(i << 4) & 0x3f];
284             out[2] = S_BASE64PAD;
285             out[3] = S_BASE64PAD;
286             writer.write(out, 0, 4);
287         } else if (rest == 2) {
288             int i = ((data[rindex] & 0xff) << 8) + (data[rindex + 1] & 0xff);
289             out[0] = S_BASE64CHAR[i >> 10];
290             out[1] = S_BASE64CHAR[(i >> 4) & 0x3f];
291             out[2] = S_BASE64CHAR[(i << 2) & 0x3f];
292             out[3] = S_BASE64PAD;
293             writer.write(out, 0, 4);
294         }
295     }
296 }
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