* Calculate a CRC, the RNC way. It re-computes its CRC table every * time it's run, but who cares? ;-) */
| 346 | * time it's run, but who cares? ;-) |
| 347 | */ |
| 348 | long rnc_crc (void *data, long len) { |
| 349 | unsigned short crctab[256]; |
| 350 | unsigned short val; |
| 351 | int i, j; |
| 352 | unsigned char *p = (unsigned char*) data; |
| 353 | |
| 354 | for (i=0; i<256; i++) { |
| 355 | val = i; |
| 356 | |
| 357 | for (j=0; j<8; j++) { |
| 358 | if (val & 1) |
| 359 | val = (val >> 1) ^ 0xA001; |
| 360 | else |
| 361 | val = (val >> 1); |
| 362 | } |
| 363 | crctab[i] = val; |
| 364 | } |
| 365 | |
| 366 | val = 0; |
| 367 | while (len--) { |
| 368 | val ^= *p++; |
| 369 | val = (val >> 8) ^ crctab[val & 0xFF]; |
| 370 | } |
| 371 | |
| 372 | return val; |
| 373 | } |