5 private static final byte[] encodingTable = {
6 (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
7 (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
8 (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U',
9 (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
10 (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
11 (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
12 (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u',
13 (byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z', (byte)'0', (byte)'1',
14 (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7', (byte)'8',
15 (byte)'9', (byte)'+', (byte)'/'
19 * encode the input data producong a base 64 encoded byte array.
21 * @return a byte array containing the base 64 encoded data.
23 public static byte[] encode(byte[] data) {
26 int modulus = data.length % 3;
28 bytes = new byte[4 * data.length / 3];
30 bytes = new byte[4 * ((data.length / 3) + 1)];
33 int dataLength = (data.length - modulus);
35 for (int i = 0, j = 0; i < dataLength; i += 3, j += 4) {
37 a2 = data[i + 1] & 0xff;
38 a3 = data[i + 2] & 0xff;
40 bytes[j] = encodingTable[(a1 >>> 2) & 0x3f];
41 bytes[j + 1] = encodingTable[((a1 << 4) | (a2 >>> 4)) & 0x3f];
42 bytes[j + 2] = encodingTable[((a2 << 2) | (a3 >>> 6)) & 0x3f];
43 bytes[j + 3] = encodingTable[a3 & 0x3f];
50 case 0: /* nothing left to do */
53 d1 = data[data.length - 1] & 0xff;
54 b1 = (d1 >>> 2) & 0x3f;
55 b2 = (d1 << 4) & 0x3f;
57 bytes[bytes.length - 4] = encodingTable[b1];
58 bytes[bytes.length - 3] = encodingTable[b2];
59 bytes[bytes.length - 2] = (byte)'=';
60 bytes[bytes.length - 1] = (byte)'=';
63 d1 = data[data.length - 2] & 0xff;
64 d2 = data[data.length - 1] & 0xff;
66 b1 = (d1 >>> 2) & 0x3f;
67 b2 = ((d1 << 4) | (d2 >>> 4)) & 0x3f;
68 b3 = (d2 << 2) & 0x3f;
70 bytes[bytes.length - 4] = encodingTable[b1];
71 bytes[bytes.length - 3] = encodingTable[b2];
72 bytes[bytes.length - 2] = encodingTable[b3];
73 bytes[bytes.length - 1] = (byte)'=';
80 private static final byte[] decodingTable;
83 decodingTable = new byte[128];
84 for (int i = 'A'; i <= 'Z'; i++) decodingTable[i] = (byte)(i - 'A');
85 for (int i = 'a'; i <= 'z'; i++) decodingTable[i] = (byte)(i - 'a' + 26);
86 for (int i = '0'; i <= '9'; i++) decodingTable[i] = (byte)(i - '0' + 52);
87 decodingTable['+'] = 62;
88 decodingTable['/'] = 63;
92 * decode the base 64 encoded input data.
94 * @return a byte array representing the decoded data.
96 public static byte[] decode(byte[] data) {
100 if (data[data.length - 2] == '=') bytes = new byte[(((data.length / 4) - 1) * 3) + 1];
101 else if (data[data.length - 1] == '=') bytes = new byte[(((data.length / 4) - 1) * 3) + 2];
102 else bytes = new byte[((data.length / 4) * 3)];
104 for (int i = 0, j = 0; i < data.length - 4; i += 4, j += 3) {
105 b1 = decodingTable[data[i]];
106 b2 = decodingTable[data[i + 1]];
107 b3 = decodingTable[data[i + 2]];
108 b4 = decodingTable[data[i + 3]];
110 bytes[j] = (byte)((b1 << 2) | (b2 >> 4));
111 bytes[j + 1] = (byte)((b2 << 4) | (b3 >> 2));
112 bytes[j + 2] = (byte)((b3 << 6) | b4);
115 if (data[data.length - 2] == '=') {
116 b1 = decodingTable[data[data.length - 4]];
117 b2 = decodingTable[data[data.length - 3]];
118 bytes[bytes.length - 1] = (byte)((b1 << 2) | (b2 >> 4));
119 } else if (data[data.length - 1] == '=') {
120 b1 = decodingTable[data[data.length - 4]];
121 b2 = decodingTable[data[data.length - 3]];
122 b3 = decodingTable[data[data.length - 2]];
123 bytes[bytes.length - 2] = (byte)((b1 << 2) | (b2 >> 4));
124 bytes[bytes.length - 1] = (byte)((b2 << 4) | (b3 >> 2));
126 b1 = decodingTable[data[data.length - 4]];
127 b2 = decodingTable[data[data.length - 3]];
128 b3 = decodingTable[data[data.length - 2]];
129 b4 = decodingTable[data[data.length - 1]];
130 bytes[bytes.length - 3] = (byte)((b1 << 2) | (b2 >> 4));
131 bytes[bytes.length - 2] = (byte)((b2 << 4) | (b3 >> 2));
132 bytes[bytes.length - 1] = (byte)((b3 << 6) | b4);
138 * decode the base 64 encoded String data.
140 * @return a byte array representing the decoded data.
142 public static byte[] decode(String data) {
146 if (data.charAt(data.length() - 2) == '=')
147 bytes = new byte[(((data.length() / 4) - 1) * 3) + 1];
148 else if (data.charAt(data.length() - 1) == '=')
149 bytes = new byte[(((data.length() / 4) - 1) * 3) + 2];
151 bytes = new byte[((data.length() / 4) * 3)];
153 for (int i = 0, j = 0; i < data.length() - 4; i += 4, j += 3) {
154 b1 = decodingTable[data.charAt(i)];
155 b2 = decodingTable[data.charAt(i + 1)];
156 b3 = decodingTable[data.charAt(i + 2)];
157 b4 = decodingTable[data.charAt(i + 3)];
159 bytes[j] = (byte)((b1 << 2) | (b2 >> 4));
160 bytes[j + 1] = (byte)((b2 << 4) | (b3 >> 2));
161 bytes[j + 2] = (byte)((b3 << 6) | b4);
164 if (data.charAt(data.length() - 2) == '=') {
165 b1 = decodingTable[data.charAt(data.length() - 4)];
166 b2 = decodingTable[data.charAt(data.length() - 3)];
167 bytes[bytes.length - 1] = (byte)((b1 << 2) | (b2 >> 4));
168 } else if (data.charAt(data.length() - 1) == '=') {
169 b1 = decodingTable[data.charAt(data.length() - 4)];
170 b2 = decodingTable[data.charAt(data.length() - 3)];
171 b3 = decodingTable[data.charAt(data.length() - 2)];
172 bytes[bytes.length - 2] = (byte)((b1 << 2) | (b2 >> 4));
173 bytes[bytes.length - 1] = (byte)((b2 << 4) | (b3 >> 2));
175 b1 = decodingTable[data.charAt(data.length() - 4)];
176 b2 = decodingTable[data.charAt(data.length() - 3)];
177 b3 = decodingTable[data.charAt(data.length() - 2)];
178 b4 = decodingTable[data.charAt(data.length() - 1)];
179 bytes[bytes.length - 3] = (byte)((b1 << 2) | (b2 >> 4));
180 bytes[bytes.length - 2] = (byte)((b2 << 4) | (b3 >> 2));
181 bytes[bytes.length - 1] = (byte)((b3 << 6) | b4);