Author: ods15 Date: Fri Mar 17 12:55:46 2006 New Revision: 111 Log: use a small LUT crc, probably faster, doesn't really matter Modified: trunk/libnut/priv.h Modified: trunk/libnut/priv.h ============================================================================== --- trunk/libnut/priv.h (original) +++ trunk/libnut/priv.h Fri Mar 17 12:55:46 2006 @@ -159,11 +159,17 @@ }; static inline uint32_t crc32(uint8_t * buf, int len){ - int32_t crc = 0; - int i; + static const uint32_t table[16] = { + 0x00000000, 0x04C11DB7, 0x09823B6E, 0x0D4326D9, + 0x130476DC, 0x17C56B6B, 0x1A864DB2, 0x1E475005, + 0x2608EDB8, 0x22C9F00F, 0x2F8AD6D6, 0x2B4BCB61, + 0x350C9B64, 0x31CD86D3, 0x3C8EA00A, 0x384FBDBD, + }; + uint32_t crc = 0; while (len--) { crc ^= *buf++ << 24; - for(i = 0; i < 8; i++) crc = (crc<<1) ^ (0x04C11DB7 & (crc>>31)); + crc = (crc<<4) ^ table[crc>>28]; + crc = (crc<<4) ^ table[crc>>28]; } return crc; }