| | 1 | /* ------------------------------------------------------------------------ */ |
| | 2 | /* */ |
| | 3 | /* CRC-calculation routines. */ |
| | 4 | /* */ |
| | 5 | /* ------------------------------------------------------------------------ */ |
| | 6 | |
| | 7 | #include "uac_crc.h" |
| | 8 | |
| | 9 | |
| | 10 | ULONG crctable[256]; |
| | 11 | ULONG rd_crc=0; |
| | 12 | |
| | 13 | |
| | 14 | void make_crctable(void) // initializes CRC table |
| | 15 | { |
| | 16 | ULONG r, |
| | 17 | i, |
| | 18 | j; |
| | 19 | |
| | 20 | for (i = 0; i <= 255; i++) |
| | 21 | { |
| | 22 | for (r = i, j = 8; j; j--) |
| | 23 | r = (r & 1) ? (r >> 1) ^ CRCPOLY : (r >> 1); |
| | 24 | crctable[i] = r; |
| | 25 | } |
| | 26 | } |
| | 27 | |
| | 28 | // Updates crc from addr till addr+len-1 |
| | 29 | // |
| | 30 | ULONG getcrc(ULONG crc, UCHAR * addr, INT len) |
| | 31 | { |
| | 32 | while (len--) |
| | 33 | crc = crctable[(unsigned char) crc ^ (*addr++)] ^ (crc >> 8); |
| | 34 | return (crc); |
| | 35 | } |
| | 36 | |
projects / wxWidgets.git / blame_incremental