1 /* 7zCrcOpt.c -- CRC32 calculation : optimized version
2 2009-11-23 : Igor Pavlov : Public domain */
3
4 #if defined(_WIN32)
5 #include <WinSock2.h>
6 #include <Windows.h>
7 #endif
8
9 #include "CpuArch.h"
10
11 #ifdef MY_CPU_LE
12
13 #define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8))
14
CrcUpdateT4(UInt32 v,const void * data,size_t size,const UInt32 * table)15 UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table)
16 {
17 const Byte *p = (const Byte *)data;
18 for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
19 v = CRC_UPDATE_BYTE_2(v, *p);
20 for (; size >= 4; size -= 4, p += 4)
21 {
22 v ^= *(const UInt32 *)p;
23 v =
24 table[0x300 + (v & 0xFF)] ^
25 table[0x200 + ((v >> 8) & 0xFF)] ^
26 table[0x100 + ((v >> 16) & 0xFF)] ^
27 table[0x000 + ((v >> 24))];
28 }
29 for (; size > 0; size--, p++)
30 v = CRC_UPDATE_BYTE_2(v, *p);
31 return v;
32 }
33
CrcUpdateT8(UInt32 v,const void * data,size_t size,const UInt32 * table)34 UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table)
35 {
36 return CrcUpdateT4(v, data, size, table);
37 }
38
39 #endif
40