KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > gnu > kawa > xml > Base64Binary


1 package gnu.kawa.xml;
2
3 /** A BinaryObject whose lexical format is base64. */
4
5 public class Base64Binary extends BinaryObject
6 {
7   public Base64Binary (byte[] data)
8   {
9     this.data = data;
10   }
11
12   public static final String JavaDoc ENCODING
13   = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
14
15   public static Base64Binary valueOf (String JavaDoc str)
16   {
17     return new Base64Binary(str);
18   }
19
20   public Base64Binary (String JavaDoc str)
21   {
22     int len = str.length();
23     int blen = 0;
24     for (int i = 0; i < len; i++)
25       {
26         char ch = str.charAt(i);
27         if (! Character.isWhitespace(ch) && ch != '=')
28           blen++;
29       }
30     blen = (3 * blen) / 4;
31     byte[] bytes = new byte[blen];
32
33     int value = 0;
34     int buffered = 0;
35     int padding = 0;
36     blen = 0;
37     for (int i = 0; i < len; i++)
38       {
39         char ch = str.charAt(i);
40         int v;
41         if (ch >= 'A' && ch <= 'Z')
42           v = ch - 'A';
43         else if (ch >= 'a' && ch <= 'z')
44           v = ch - 'a' + 26;
45         else if (ch >= '0' && ch <= '9')
46           v = ch - '0' + 52;
47         else if (ch == '+')
48           v = 62;
49         else if (ch == '/')
50           v = 63;
51         else if (Character.isWhitespace(ch))
52           continue;
53         else if (ch == '=')
54           {
55             padding++;
56             continue;
57           }
58         else
59           v = -1;
60         if (v < 0 || padding > 0)
61           throw new IllegalArgumentException JavaDoc("illegal character in base64Binary string at position "+i);
62         value = (value << 6) + v;
63         buffered++;
64         if (buffered == 4)
65           {
66             bytes[blen++] = (byte) (value >> 16);
67             bytes[blen++] = (byte) (value >> 8);
68             bytes[blen++] = (byte) (value);
69             buffered = 0;
70           }
71         /*
72         if (buffered == 4 || ++i == len)
73           {
74             System.err.println("end bl:"+blen+" b:"+buffered+" val:"+Integer.toHexString(value)+" i:"+i);
75             while (--buffered >= 0)
76               {
77                 System.err.println("bl:"+blen+" buf:"+buffered);
78                 bytes[blen++] = (byte) (value >> (8 * buffered));
79               }
80             bytes[blen++] = (byte) (value >> 16);
81             bytes[blen++] = (byte) (value >> 8);
82             bytes[blen++] = (byte) (value);
83             buffered = 0;
84           }
85         */
86       }
87     if (buffered+padding > 0
88         ? (buffered + padding != 4
89            || (value & ((1 << padding) - 1)) != 0
90            || blen + 3 - padding != bytes.length)
91         : blen != bytes.length)
92       throw new IllegalArgumentException JavaDoc();
93     switch (padding)
94       {
95       case 1:
96         bytes[blen++] = (byte) (value << 10);
97         bytes[blen++] = (byte) (value >> 2);
98         break;
99       case 2:
100         bytes[blen++] = (byte) (value >> 4);
101         break;
102       }
103     //System.err.println("end bl:"+blen+" b:"+buffered+" val:"+Integer.toHexString(value)+" pad:"+padding);
104 this.data = bytes;
105   }
106
107   public StringBuffer JavaDoc toString (StringBuffer JavaDoc sbuf)
108   {
109     byte[] bb = data;
110     int len = bb.length;
111     int value = 0;
112     for (int i = 0; i < len; )
113       {
114         byte b = bb[i];
115         value = (value << 8) | (b & 0xFF);
116         i++;
117         if ((i % 3) == 0)
118           {
119             sbuf.append(ENCODING.charAt((value >> 18) & 63));
120             sbuf.append(ENCODING.charAt((value >> 12) & 63));
121             sbuf.append(ENCODING.charAt((value >> 6) & 63));
122             sbuf.append(ENCODING.charAt(value & 63));
123           }
124       }
125     switch (len % 3)
126       {
127       case 1:
128         sbuf.append(ENCODING.charAt((value >> 2) & 63));
129         sbuf.append(ENCODING.charAt((value << 4) & 63));
130         sbuf.append("==");
131         break;
132       case 2:
133         sbuf.append(ENCODING.charAt((value >> 10) & 63));
134         sbuf.append(ENCODING.charAt((value >> 4) & 63));
135         sbuf.append(ENCODING.charAt((value << 2) & 63));
136         sbuf.append('=');
137         break;
138       }
139     return sbuf;
140   }
141
142   public String JavaDoc toString ()
143   {
144     return toString(new StringBuffer JavaDoc()).toString();
145   }
146 }
147
Popular Tags