| 285 | } |
| 286 | |
| 287 | string EncodeBase32(const unsigned char* pch, size_t len) |
| 288 | { |
| 289 | static const char* pbase32 = "abcdefghijklmnopqrstuvwxyz234567"; |
| 290 | |
| 291 | string strRet = ""; |
| 292 | strRet.reserve((len + 4) / 5 * 8); |
| 293 | |
| 294 | int mode = 0, left = 0; |
| 295 | const unsigned char* pchEnd = pch + len; |
| 296 | |
| 297 | while (pch < pchEnd) { |
| 298 | int enc = *(pch++); |
| 299 | switch (mode) { |
| 300 | case 0: // we have no bits |
| 301 | strRet += pbase32[enc >> 3]; |
| 302 | left = (enc & 7) << 2; |
| 303 | mode = 1; |
| 304 | break; |
| 305 | |
| 306 | case 1: // we have three bits |
| 307 | strRet += pbase32[left | (enc >> 6)]; |
| 308 | strRet += pbase32[(enc >> 1) & 31]; |
| 309 | left = (enc & 1) << 4; |
| 310 | mode = 2; |
| 311 | break; |
| 312 | |
| 313 | case 2: // we have one bit |
| 314 | strRet += pbase32[left | (enc >> 4)]; |
| 315 | left = (enc & 15) << 1; |
| 316 | mode = 3; |
| 317 | break; |
| 318 | |
| 319 | case 3: // we have four bits |
| 320 | strRet += pbase32[left | (enc >> 7)]; |
| 321 | strRet += pbase32[(enc >> 2) & 31]; |
| 322 | left = (enc & 3) << 3; |
| 323 | mode = 4; |
| 324 | break; |
| 325 | |
| 326 | case 4: // we have two bits |
| 327 | strRet += pbase32[left | (enc >> 5)]; |
| 328 | strRet += pbase32[enc & 31]; |
| 329 | mode = 0; |
| 330 | } |
| 331 | } |
| 332 | |
| 333 | static const int nPadding[5] = {0, 6, 4, 3, 1}; |
| 334 | if (mode) { |
| 335 | strRet += pbase32[left]; |
| 336 | for (int n = 0; n < nPadding[mode]; n++) |
| 337 | strRet += '='; |
| 338 | } |
| 339 | |
| 340 | return strRet; |
| 341 | } |
| 342 | |
| 343 | string EncodeBase32(const string& str) |
| 344 | { |