1 package org.bouncycastle.util.encoders;
5 private static byte[] encodingTable =
7 (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
8 (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
9 (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U',
10 (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
11 (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
12 (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
13 (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u',
15 (byte)'w', (byte)'x', (byte)'y', (byte)'z',
16 (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6',
17 (byte)'7', (byte)'8', (byte)'9',
22 * encode the input data producong a base 64 encoded byte array.
24 * @return a byte array containing the base 64 encoded data.
26 public static byte[] encode(
31 if ((data.length % 3) == 0)
33 bytes = new byte[4 * data.length / 3];
37 bytes = new byte[4 * ((data.length / 3) + 1)];
40 for (int i = 0, j = 0;
41 i < ((data.length / 3) * 3); i += 3, j += 4)
47 d2 = data[i + 1] & 0xff;
48 d3 = data[i + 2] & 0xff;
50 b1 = (d1 >>> 2) & 0x3f;
51 b2 = ((d1 << 4) | (d2 >>> 4)) & 0x3f;
52 b3 = ((d2 << 2) | (d3 >>> 6)) & 0x3f;
55 bytes[j] = encodingTable[b1];
56 bytes[j + 1] = encodingTable[b2];
57 bytes[j + 2] = encodingTable[b3];
58 bytes[j + 3] = encodingTable[b4];
62 * process the tail end.
67 switch (data.length % 3)
69 case 0: /* nothing left to do */
72 d1 = data[data.length - 1] & 0xff;
73 b1 = (d1 >>> 2) & 0x3f;
74 b2 = (d1 << 4) & 0x3f;
76 bytes[bytes.length - 4] = encodingTable[b1];
77 bytes[bytes.length - 3] = encodingTable[b2];
78 bytes[bytes.length - 2] = (byte)'=';
79 bytes[bytes.length - 1] = (byte)'=';
82 d1 = data[data.length - 2] & 0xff;
83 d2 = data[data.length - 1] & 0xff;
85 b1 = (d1 >>> 2) & 0x3f;
86 b2 = ((d1 << 4) | (d2 >>> 4)) & 0x3f;
87 b3 = (d2 << 2) & 0x3f;
89 bytes[bytes.length - 4] = encodingTable[b1];
90 bytes[bytes.length - 3] = encodingTable[b2];
91 bytes[bytes.length - 2] = encodingTable[b3];
92 bytes[bytes.length - 1] = (byte)'=';
100 * set up the decoding table.
102 private static byte[] decodingTable;
106 decodingTable = new byte[128];
108 for (int i = 'A'; i <= 'Z'; i++)
110 decodingTable[i] = (byte)(i - 'A');
113 for (int i = 'a'; i <= 'z'; i++)
115 decodingTable[i] = (byte)(i - 'a' + 26);
118 for (int i = '0'; i <= '9'; i++)
120 decodingTable[i] = (byte)(i - '0' + 52);
123 decodingTable['+'] = 62;
124 decodingTable['/'] = 63;
128 * decode the base 64 encoded input data.
130 * @return a byte array representing the decoded data.
132 public static byte[] decode(
138 if (data[data.length - 2] == '=')
140 bytes = new byte[(((data.length / 4) - 1) * 3) + 1];
142 else if (data[data.length - 1] == '=')
144 bytes = new byte[(((data.length / 4) - 1) * 3) + 2];
148 bytes = new byte[((data.length / 4) * 3)];
151 for (int i = 0, j = 0; i < data.length - 4; i += 4, j += 3)
153 b1 = decodingTable[data[i]];
154 b2 = decodingTable[data[i + 1]];
155 b3 = decodingTable[data[i + 2]];
156 b4 = decodingTable[data[i + 3]];
158 bytes[j] = (byte)((b1 << 2) | (b2 >> 4));
159 bytes[j + 1] = (byte)((b2 << 4) | (b3 >> 2));
160 bytes[j + 2] = (byte)((b3 << 6) | b4);
163 if (data[data.length - 2] == '=')
165 b1 = decodingTable[data[data.length - 4]];
166 b2 = decodingTable[data[data.length - 3]];
168 bytes[bytes.length - 1] = (byte)((b1 << 2) | (b2 >> 4));
170 else if (data[data.length - 1] == '=')
172 b1 = decodingTable[data[data.length - 4]];
173 b2 = decodingTable[data[data.length - 3]];
174 b3 = decodingTable[data[data.length - 2]];
176 bytes[bytes.length - 2] = (byte)((b1 << 2) | (b2 >> 4));
177 bytes[bytes.length - 1] = (byte)((b2 << 4) | (b3 >> 2));
181 b1 = decodingTable[data[data.length - 4]];
182 b2 = decodingTable[data[data.length - 3]];
183 b3 = decodingTable[data[data.length - 2]];
184 b4 = decodingTable[data[data.length - 1]];
186 bytes[bytes.length - 3] = (byte)((b1 << 2) | (b2 >> 4));
187 bytes[bytes.length - 2] = (byte)((b2 << 4) | (b3 >> 2));
188 bytes[bytes.length - 1] = (byte)((b3 << 6) | b4);
195 * decode the base 64 encoded String data.
197 * @return a byte array representing the decoded data.
199 public static byte[] decode(
205 if (data.charAt(data.length() - 2) == '=')
207 bytes = new byte[(((data.length() / 4) - 1) * 3) + 1];
209 else if (data.charAt(data.length() - 1) == '=')
211 bytes = new byte[(((data.length() / 4) - 1) * 3) + 2];
215 bytes = new byte[((data.length() / 4) * 3)];
218 for (int i = 0, j = 0; i < data.length() - 4; i += 4, j += 3)
220 b1 = decodingTable[data.charAt(i)];
221 b2 = decodingTable[data.charAt(i + 1)];
222 b3 = decodingTable[data.charAt(i + 2)];
223 b4 = decodingTable[data.charAt(i + 3)];
225 bytes[j] = (byte)((b1 << 2) | (b2 >> 4));
226 bytes[j + 1] = (byte)((b2 << 4) | (b3 >> 2));
227 bytes[j + 2] = (byte)((b3 << 6) | b4);
230 if (data.charAt(data.length() - 2) == '=')
232 b1 = decodingTable[data.charAt(data.length() - 4)];
233 b2 = decodingTable[data.charAt(data.length() - 3)];
235 bytes[bytes.length - 1] = (byte)((b1 << 2) | (b2 >> 4));
237 else if (data.charAt(data.length() - 1) == '=')
239 b1 = decodingTable[data.charAt(data.length() - 4)];
240 b2 = decodingTable[data.charAt(data.length() - 3)];
241 b3 = decodingTable[data.charAt(data.length() - 2)];
243 bytes[bytes.length - 2] = (byte)((b1 << 2) | (b2 >> 4));
244 bytes[bytes.length - 1] = (byte)((b2 << 4) | (b3 >> 2));
248 b1 = decodingTable[data.charAt(data.length() - 4)];
249 b2 = decodingTable[data.charAt(data.length() - 3)];
250 b3 = decodingTable[data.charAt(data.length() - 2)];
251 b4 = decodingTable[data.charAt(data.length() - 1)];
253 bytes[bytes.length - 3] = (byte)((b1 << 2) | (b2 >> 4));
254 bytes[bytes.length - 2] = (byte)((b2 << 4) | (b3 >> 2));
255 bytes[bytes.length - 1] = (byte)((b3 << 6) | b4);