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.axis.encoding ;
17  
18  import org.apache.axis.utils.Messages;
19  
20  import java.io.IOException  ;
21  import java.io.OutputStream  ;
22  import java.io.Writer  ;
23  
24  /**
25   *
26   * @author TAMURA Kent &lt;kent@trl.ibm.co.jp&gt;
27   */
28  public class Base64 {
29      private static final char[] S_BASE64CHAR = {
30          'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 
31          'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 
32          'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 
33          'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 
34          'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 
35          'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', 
36          '8', '9', '+', '/'
37      };
38      private static final char S_BASE64PAD = '=';
39      private static final byte[] S_DECODETABLE = new byte[128];
40      static {
41          for (int i = 0;  i < S_DECODETABLE.length;  i ++)
42              S_DECODETABLE[i] = Byte.MAX_VALUE;  // 127
43          for (int i = 0;  i < S_BASE64CHAR.length;  i ++) // 0 to 63
44              S_DECODETABLE[S_BASE64CHAR[i]] = (byte)i;
45      }
46  
47      private static int decode0(char[] ibuf, byte[] obuf, int wp) {
48          int outlen = 3;
49          if (ibuf[3] == S_BASE64PAD)  outlen = 2;
50          if (ibuf[2] == S_BASE64PAD)  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  (Messages.getMessage("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
84                  || ch < S_DECODETABLE.length && 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
110                 || ch < S_DECODETABLE.length && 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, OutputStream   ostream) throws IOException   {
129         char[] ibuf = new char[4];
130         int ibufcount = 0;
131         byte[] obuf = new byte[3];
132         for (int i = off;  i < off+len;  i ++) {
133             char ch = data[i];
134             if (ch == S_BASE64PAD
135                 || ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE) {
136                 ibuf[ibufcount++] = ch;
137                 if (ibufcount == ibuf.length) {
138                     ibufcount = 0;
139                     int obufcount = decode0(ibuf, obuf, 0);
140                     ostream.write(obuf, 0, obufcount);
141                 }
142             }
143         }
144     }
145 
146     /**
147      *
148      */
149     public static void decode(String   data, OutputStream   ostream) throws IOException   {
150         char[] ibuf = new char[4];
151         int ibufcount = 0;
152         byte[] obuf = new byte[3];
153         for (int i = 0;  i < data.length();  i ++) {
154             char ch = data.charAt(i);
155             if (ch == S_BASE64PAD
156                 || ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE) {
157                 ibuf[ibufcount++] = ch;
158                 if (ibufcount == ibuf.length) {
159                     ibufcount = 0;
160                     int obufcount = decode0(ibuf, obuf, 0);
161                     ostream.write(obuf, 0, obufcount);
162                 }
163             }
164         }
165     }
166 
167     /**
168      * Returns base64 representation of specified byte array.
169      */
170     public static String   encode(byte[] data) {
171         return encode(data, 0, data.length);
172     }
173 
174     /**
175      * Returns base64 representation of specified byte array.
176      */
177     public static String   encode(byte[] data, int off, int len) {
178         if (len <= 0)  return "";
179         char[] out = new char[len/3*4+4];
180         int rindex = off;
181         int windex = 0;
182         int rest = len-off;
183         while (rest >= 3) {
184             int i = ((data[rindex]&0xff)<<16)
185                     +((data[rindex+1]&0xff)<<8)
186                     +(data[rindex+2]&0xff);
187             out[windex++] = S_BASE64CHAR[i>>18];
188             out[windex++] = S_BASE64CHAR[(i>>12)&0x3f];
189             out[windex++] = S_BASE64CHAR[(i>>6)&0x3f];
190             out[windex++] = S_BASE64CHAR[i&0x3f];
191             rindex += 3;
192             rest -= 3;
193         }
194         if (rest == 1) {
195             int i = data[rindex]&0xff;
196             out[windex++] = S_BASE64CHAR[i>>2];
197             out[windex++] = S_BASE64CHAR[(i<<4)&0x3f];
198             out[windex++] = S_BASE64PAD;
199             out[windex++] = S_BASE64PAD;
200         } else if (rest == 2) {
201             int i = ((data[rindex]&0xff)<<8)+(data[rindex+1]&0xff);
202             out[windex++] = S_BASE64CHAR[i>>10];
203             out[windex++] = S_BASE64CHAR[(i>>4)&0x3f];
204             out[windex++] = S_BASE64CHAR[(i<<2)&0x3f];
205             out[windex++] = S_BASE64PAD;
206         }
207         return new String  (out, 0, windex);
208     }
209 
210     /**
211      * Outputs base64 representation of the specified byte array to a byte stream.
212      */
213     public static void encode(byte[] data, int off, int len, OutputStream   ostream) throws IOException   {
214         if (len <= 0)  return;
215         byte[] out = new byte[4];
216         int rindex = off;
217         int rest = len-off;
218         while (rest >= 3) {
219             int i = ((data[rindex]&0xff)<<16)
220                     +((data[rindex+1]&0xff)<<8)
221                     +(data[rindex+2]&0xff);
222             out[0] = (byte)S_BASE64CHAR[i>>18];
223             out[1] = (byte)S_BASE64CHAR[(i>>12)&0x3f];
224             out[2] = (byte)S_BASE64CHAR[(i>>6)&0x3f];
225             out[3] = (byte)S_BASE64CHAR[i&0x3f];
226             ostream.write(out, 0, 4);
227             rindex += 3;
228             rest -= 3;
229         }
230         if (rest == 1) {
231             int i = data[rindex]&0xff;
232             out[0] = (byte)S_BASE64CHAR[i>>2];
233             out[1] = (byte)S_BASE64CHAR[(i<<4)&0x3f];
234             out[2] = (byte)S_BASE64PAD;
235             out[3] = (byte)S_BASE64PAD;
236             ostream.write(out, 0, 4);
237         } else if (rest == 2) {
238             int i = ((data[rindex]&0xff)<<8)+(data[rindex+1]&0xff);
239             out[0] = (byte)S_BASE64CHAR[i>>10];
240             out[1] = (byte)S_BASE64CHAR[(i>>4)&0x3f];
241             out[2] = (byte)S_BASE64CHAR[(i<<2)&0x3f];
242             out[3] = (byte)S_BASE64PAD;
243             ostream.write(out, 0, 4);
244         }
245     }
246 
247     /**
248      * Outputs base64 representation of the specified byte array to a character stream.
249      */
250     public static void encode(byte[] data, int off, int len, Writer   writer) throws IOException   {
251         if (len <= 0)  return;
252         char[] out = new char[4];
253         int rindex = off;
254         int rest = len-off;
255         int output = 0;
256         while (rest >= 3) {
257             int i = ((data[rindex]&0xff)<<16)
258                     +((data[rindex+1]&0xff)<<8)
259                     +(data[rindex+2]&0xff);
260             out[0] = S_BASE64CHAR[i>>18];
261             out[1] = S_BASE64CHAR[(i>>12)&0x3f];
262             out[2] = S_BASE64CHAR[(i>>6)&0x3f];
263             out[3] = S_BASE64CHAR[i&0x3f];
264             writer.write(out, 0, 4);
265             rindex += 3;
266             rest -= 3;
267             output += 4;
268             if (output % 76 == 0)
269                 writer.write("\n");
270         }
271         if (rest == 1) {
272             int i = data[rindex]&0xff;
273             out[0] = S_BASE64CHAR[i>>2];
274             out[1] = S_BASE64CHAR[(i<<4)&0x3f];
275             out[2] = S_BASE64PAD;
276             out[3] = S_BASE64PAD;
277             writer.write(out, 0, 4);
278         } else if (rest == 2) {
279             int i = ((data[rindex]&0xff)<<8)+(data[rindex+1]&0xff);
280             out[0] = S_BASE64CHAR[i>>10];
281             out[1] = S_BASE64CHAR[(i>>4)&0x3f];
282             out[2] = S_BASE64CHAR[(i<<2)&0x3f];
283             out[3] = S_BASE64PAD;
284             writer.write(out, 0, 4);
285         }
286     }
287 }
288
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