TinyBannavi/src/tainavi/b64.java

   1 package tainavi;\r
   2 \r
   3 import java.util.ArrayList;\r
   4 \r
   5 \r
   6 \r
   7 public class b64 {\r
   8         \r
   9         private static final String list = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";\r
  10 \r
  11         public static String enc(byte[] src) {\r
  12                 String out = "";\r
  13                 \r
  14                 if (src == null) {\r
  15                         return null;\r
  16                 }\r
  17                 \r
  18                 int n = src.length;\r
  19                 byte[] b = new byte[n+1];\r
  20                 b[n] = 0x00;\r
  21                 System.arraycopy(src, 0, b, 0, n);\r
  22                 \r
  23                 int x;\r
  24                 int y;\r
  25                 int j;\r
  26                 byte c = 0;\r
  27                 for (int i=0; i<n*8; i+=6) {\r
  28                         j = (i-i%8)/8;\r
  29                         switch (i%8) {\r
  30                         case 0:\r
  31                                 x = (int)b[j];\r
  32                                 x &= 0x000000fc;\r
  33                                 x >>= 2;\r
  34                                 c = (byte)x;\r
  35                                 break;\r
  36                         case 1:\r
  37                                 x = (int)b[j];\r
  38                                 x &= 0x0000007e;\r
  39                                 x >>= 1;\r
  40                                 c = (byte)x;\r
  41                                 break;\r
  42                         case 2:\r
  43                                 x = (int)b[j];\r
  44                                 x &= 0x0000003f;\r
  45                                 c = (byte)x;\r
  46                                 break;\r
  47                         case 3:\r
  48                                 x = (int)b[j];\r
  49                                 x &= 0x0000001f;\r
  50                                 x <<= 1;\r
  51                                 y = (int)b[j+1];\r
  52                                 y &= 0x00000080;\r
  53                                 y >>= 7;\r
  54                                 c = (byte)(x|y);\r
  55                                 break;\r
  56                         case 4:\r
  57                                 x = (int)b[j];\r
  58                                 x &= 0x0000000f;\r
  59                                 x <<= 2;\r
  60                                 y = (int)b[j+1];\r
  61                                 y &= 0x000000C0;\r
  62                                 y >>= 6;\r
  63                                 c = (byte)(x|y);\r
  64                                 break;\r
  65                         case 5:\r
  66                                 x = (int)b[j];\r
  67                                 x &= 0x00000007;\r
  68                                 x <<= 3;\r
  69                                 y = (int)b[j+1];\r
  70                                 y &= 0x000000E0;\r
  71                                 y >>= 5;\r
  72                                 c = (byte)(x|y);\r
  73                                 break;\r
  74                         case 6:\r
  75                                 x = (int)b[j];\r
  76                                 x &= 0x00000003;\r
  77                                 x <<= 4;\r
  78                                 y = (int)b[j+1];\r
  79                                 y &= 0x000000F0;\r
  80                                 y >>= 4;\r
  81                                 c = (byte)(x|y);\r
  82                                 break;\r
  83                         case 7:\r
  84                                 x = (int)b[j];\r
  85                                 x &= 0x00000001;\r
  86                                 x <<= 5;\r
  87                                 y = (int)b[j+1];\r
  88                                 y &= 0x000000F8;\r
  89                                 y >>= 3;\r
  90                                 c = (byte)(x|y);\r
  91                                 break;\r
  92                         }\r
  93                         out += list.substring((int)c,(int)c+1);\r
  94                 }\r
  95                 for (int i=out.length(); i%4 != 0; i++) {\r
  96                         out += "=";\r
  97                 }\r
  98                 return(out);\r
  99         }\r
 100                 \r
 101         public static byte[] dec(String src){\r
 102                 \r
 103                 if (src == null) {\r
 104                         return null;\r
 105                 }\r
 106                 \r
 107                 ArrayList<Byte> ba = new ArrayList<Byte>();\r
 108                 \r
 109                 int x;\r
 110                 int y;\r
 111                 int m = 0;\r
 112                 byte c = 0;\r
 113                 int n = src.length();\r
 114                 for (int i=0; i<n; i++) {\r
 115                         //\r
 116                         int b = list.indexOf(src.charAt(i));\r
 117                         if (b == -1) {\r
 118                                 break;\r
 119                         }\r
 120                         \r
 121                         //\r
 122                         //int j = i / 4;\r
 123                         switch (m = i%4) {\r
 124                         case 0:\r
 125                                 x = b;\r
 126                                 x &= 0x0000003f;\r
 127                                 x <<= 2;\r
 128                                 c = (byte)x;\r
 129                                 ba.add(c);\r
 130                                 break;\r
 131                         case 1:\r
 132                                 x = b;\r
 133                                 x &= 0x00000030;\r
 134                                 x >>= 4;\r
 135                                 c = ba.remove(ba.size()-1);\r
 136                                 c |= (byte)x;\r
 137                                 ba.add(c);\r
 138                                 //\r
 139                                 y = b;\r
 140                                 y &= 0x0000000f;\r
 141                                 y <<= 4;\r
 142                                 c = (byte)y;\r
 143                                 ba.add(c);\r
 144                                 break;\r
 145                         case 2:\r
 146                                 x = b;\r
 147                                 x &= 0x0000003C;\r
 148                                 x >>= 2;\r
 149                                 c = ba.remove(ba.size()-1);\r
 150                                 c |= (byte)x;\r
 151                                 ba.add(c);\r
 152                                 //\r
 153                                 y = b;\r
 154                                 y &= 0x00000003;\r
 155                                 y <<= 6;\r
 156                                 c = (byte)y;\r
 157                                 ba.add(c);\r
 158                                 break;\r
 159                         case 3:\r
 160                                 x = b;\r
 161                                 x &= 0x0000003f;\r
 162                                 c = ba.remove(ba.size()-1);\r
 163                                 c |= (byte)x;\r
 164                                 ba.add(c);\r
 165                                 break;\r
 166                         }\r
 167                 }\r
 168                 \r
 169                 // 端数切捨て\r
 170                 if (ba.size() > 0 && m != 3) {\r
 171                         ba.remove(ba.size()-1);\r
 172                 }\r
 173                 \r
 174                 // リスト→配列\r
 175                 byte[] bb = new byte[ba.size()];\r
 176                 int i = 0;\r
 177                 for (Byte b : ba) {\r
 178                         bb[i++] = b;\r
 179                 }\r
 180                 \r
 181                 return bb;\r
 182         }\r
 183 }\r