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1
6 package org.w3c.tools.codec;
7
8 import java.io.ByteArrayInputStream  ;
9 import java.io.ByteArrayOutputStream ;
10 import java.io.FileInputStream ;
11 import java.io.IOException ;
12 import java.io.InputStream ;
13 import java.io.OutputStream ;
14 import java.io.UnsupportedEncodingException ;
15
16
22 public class Base64Decoder
23 {
24 private static final int BUFFER_SIZE = 1024;
25
26 InputStream in = null;
27 OutputStream out = null;
28 boolean stringp = false;
29
30 private void printHex(int x)
31 {
32 int h = (x & 0xf0) >> 4;
33 int l = (x & 0x0f);
34 System.out.print(
35 (new Character ((char) ((h > 9) ? 'A' + h - 10 : '0' + h)))
36 .toString()
37 + (new Character ((char) ((l > 9) ? 'A' + l - 10 : '0' + l)))
38 .toString());
39 }
40
41 private void printHex(byte buf[], int off, int len)
42 {
43 while (off < len)
44 {
45 printHex(buf[off++]);
46 System.out.print(" ");
47 }
48 System.out.println("");
49 }
50
51 private void printHex(String s)
52 {
53 byte bytes[];
54 try
55 {
56 bytes = s.getBytes("ISO-8859-1");
57 }
58 catch (UnsupportedEncodingException ex)
59 {
60 throw new RuntimeException (
61 this.getClass().getName()
62 + "[printHex] Unable to convert"
63 + "properly char to bytes");
64 }
65 printHex(bytes, 0, bytes.length);
66 }
67
68 private final int get1(byte buf[], int off)
69 {
70 return ((buf[off] & 0x3f) << 2) | ((buf[off + 1] & 0x30) >>> 4);
71 }
72
73 private final int get2(byte buf[], int off)
74 {
75 return ((buf[off + 1] & 0x0f) << 4) | ((buf[off + 2] & 0x3c) >>> 2);
76 }
77
78 private final int get3(byte buf[], int off)
79 {
80 return ((buf[off + 2] & 0x03) << 6) | (buf[off + 3] & 0x3f);
81 }
82
83 private final int check(int ch)
84 {
85 if ((ch >= 'A') && (ch <= 'Z'))
86 {
87 return ch - 'A';
88 }
89 else if ((ch >= 'a') && (ch <= 'z'))
90 {
91 return ch - 'a' + 26;
92 }
93 else if ((ch >= '0') && (ch <= '9'))
94 {
95 return ch - '0' + 52;
96 }
97 else
98 {
99 switch (ch)
100 {
101 case '=' :
102 return 65;
103 case '+' :
104 return 62;
105 case '/' :
106 return 63;
107 default :
108 return -1;
109 }
110 }
111 }
112
113
121 public void process() throws IOException , Base64FormatException
122 {
123 byte buffer[] = new byte[BUFFER_SIZE];
124 byte chunk[] = new byte[4];
125 int got = -1;
126 int ready = 0;
127
128 fill : while ((got = in.read(buffer)) > 0)
129 {
130 int skiped = 0;
131 while (skiped < got)
132 {
133 while (ready < 4)
135 {
136 if (skiped >= got)
137 continue fill;
138 int ch = check(buffer[skiped++]);
139 if (ch >= 0)
140 chunk[ready++] = (byte) ch;
141 }
142 if (chunk[2] == 65)
143 {
144 out.write(get1(chunk, 0));
145 return;
146 }
147 else if (chunk[3] == 65)
148 {
149 out.write(get1(chunk, 0));
150 out.write(get2(chunk, 0));
151 return;
152 }
153 else
154 {
155 out.write(get1(chunk, 0));
156 out.write(get2(chunk, 0));
157 out.write(get3(chunk, 0));
158 }
159 ready = 0;
160 }
161 }
162 if (ready != 0)
163 throw new Base64FormatException("Invalid length.");
164 out.flush();
165 }
166
167
177 public String processString() throws Base64FormatException
178 {
179 if (!stringp)
180 throw new RuntimeException (
181 this.getClass().getName()
182 + "[processString]"
183 + "invalid call (not a String)");
184 try
185 {
186 process();
187 }
188 catch (IOException e)
189 {
190 }
191 String s;
192 try
193 {
194 s = ((ByteArrayOutputStream ) out).toString("ISO-8859-1");
195 }
196 catch (UnsupportedEncodingException ex)
197 {
198 throw new RuntimeException (
199 this.getClass().getName()
200 + "[processString] Unable to convert"
201 + "properly char to bytes");
202 }
203 return s;
204 }
205
206
210 public Base64Decoder(String input)
211 {
212 byte bytes[];
213 try
214 {
215 bytes = input.getBytes("ISO-8859-1");
216 }
217 catch (UnsupportedEncodingException ex)
218 {
219 throw new RuntimeException (
220 this.getClass().getName()
221 + "[Constructor] Unable to convert"
222 + "properly char to bytes");
223 }
224 this.stringp = true;
225 this.in = new ByteArrayInputStream (bytes);
226 this.out = new ByteArrayOutputStream ();
227 }
228
229
234 public Base64Decoder(InputStream in, OutputStream out)
235 {
236 this.in = in;
237 this.out = out;
238 this.stringp = false;
239 }
240
241
246 public static void main(String args[])
247 {
248 if (args.length == 1)
249 {
250 try
251 {
252 Base64Decoder b = new Base64Decoder(args[0]);
253 System.out.println("[" + b.processString() + "]");
254 }
255 catch (Base64FormatException e)
256 {
257 System.out.println("Invalid Base64 format !");
258 System.exit(1);
259 }
260 }
261 else if ((args.length == 2) && (args[0].equals("-f")))
262 {
263 try
264 {
265 FileInputStream in = new FileInputStream (args[1]);
266 Base64Decoder b = new Base64Decoder(in, System.out);
267 b.process();
268 }
269 catch (Exception ex)
270 {
271 System.out.println("error: " + ex.getMessage());
272 System.exit(1);
273 }
274 }
275 else
276 {
277 System.out.println("Base64Decoder [strong] [-f file]");
278 }
279 System.exit(0);
280 }
281 }
282 |
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