| 363 | } |
| 364 | |
| 365 | string EncodeBase32(const unsigned char* pch, size_t len) { |
| 366 | static const char* pbase32 = "abcdefghijklmnopqrstuvwxyz234567"; |
| 367 | |
| 368 | string strRet = ""; |
| 369 | strRet.reserve((len + 4) / 5 * 8); |
| 370 | |
| 371 | int mode = 0, left = 0; |
| 372 | const unsigned char* pchEnd = pch + len; |
| 373 | |
| 374 | while (pch < pchEnd) { |
| 375 | int enc = *(pch++); |
| 376 | switch (mode) { |
| 377 | case 0: // we have no bits |
| 378 | strRet += pbase32[enc >> 3]; |
| 379 | left = (enc & 7) << 2; |
| 380 | mode = 1; |
| 381 | break; |
| 382 | |
| 383 | case 1: // we have three bits |
| 384 | strRet += pbase32[left | (enc >> 6)]; |
| 385 | strRet += pbase32[(enc >> 1) & 31]; |
| 386 | left = (enc & 1) << 4; |
| 387 | mode = 2; |
| 388 | break; |
| 389 | |
| 390 | case 2: // we have one bit |
| 391 | strRet += pbase32[left | (enc >> 4)]; |
| 392 | left = (enc & 15) << 1; |
| 393 | mode = 3; |
| 394 | break; |
| 395 | |
| 396 | case 3: // we have four bits |
| 397 | strRet += pbase32[left | (enc >> 7)]; |
| 398 | strRet += pbase32[(enc >> 2) & 31]; |
| 399 | left = (enc & 3) << 3; |
| 400 | mode = 4; |
| 401 | break; |
| 402 | |
| 403 | case 4: // we have two bits |
| 404 | strRet += pbase32[left | (enc >> 5)]; |
| 405 | strRet += pbase32[enc & 31]; |
| 406 | mode = 0; |
| 407 | } |
| 408 | } |
| 409 | |
| 410 | static const int nPadding[5] = {0, 6, 4, 3, 1}; |
| 411 | if (mode) { |
| 412 | strRet += pbase32[left]; |
| 413 | for (int n = 0; n < nPadding[mode]; n++) strRet += '='; |
| 414 | } |
| 415 | |
| 416 | return strRet; |
| 417 | } |
| 418 | |
| 419 | string EncodeBase32(const string& str) { |
| 420 | return EncodeBase32((const unsigned char*)str.c_str(), str.size()); |