1 /* 7zCrcOpt.c -- CRC32 calculation
2 2013-11-12 : Igor Pavlov : Public domain */
3
4 #include "Precomp.h"
5
6 #include "CpuArch.h"
7
8 #define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8))
9
10 #ifndef MY_CPU_BE
11
CrcUpdateT4(UInt32 v,const void * data,size_t size,const UInt32 * table)12 UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table)
13 {
14 const Byte *p = (const Byte *)data;
15 for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
16 v = CRC_UPDATE_BYTE_2(v, *p);
17 for (; size >= 4; size -= 4, p += 4)
18 {
19 v ^= *(const UInt32 *)p;
20 v =
21 table[0x300 + (v & 0xFF)] ^
22 table[0x200 + ((v >> 8) & 0xFF)] ^
23 table[0x100 + ((v >> 16) & 0xFF)] ^
24 table[0x000 + ((v >> 24))];
25 }
26 for (; size > 0; size--, p++)
27 v = CRC_UPDATE_BYTE_2(v, *p);
28 return v;
29 }
30
CrcUpdateT8(UInt32 v,const void * data,size_t size,const UInt32 * table)31 UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table)
32 {
33 return CrcUpdateT4(v, data, size, table);
34 }
35
36 #endif
37
38
39 #ifndef MY_CPU_LE
40
41 #define CRC_UINT32_SWAP(v) ((v >> 24) | ((v >> 8) & 0xFF00) | ((v << 8) & 0xFF0000) | (v << 24))
42
CrcUpdateT1_BeT4(UInt32 v,const void * data,size_t size,const UInt32 * table)43 UInt32 MY_FAST_CALL CrcUpdateT1_BeT4(UInt32 v, const void *data, size_t size, const UInt32 *table)
44 {
45 const Byte *p = (const Byte *)data;
46 for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
47 v = CRC_UPDATE_BYTE_2(v, *p);
48 v = CRC_UINT32_SWAP(v);
49 table += 0x100;
50 for (; size >= 4; size -= 4, p += 4)
51 {
52 v ^= *(const UInt32 *)p;
53 v =
54 table[0x000 + (v & 0xFF)] ^
55 table[0x100 + ((v >> 8) & 0xFF)] ^
56 table[0x200 + ((v >> 16) & 0xFF)] ^
57 table[0x300 + ((v >> 24))];
58 }
59 table -= 0x100;
60 v = CRC_UINT32_SWAP(v);
61 for (; size > 0; size--, p++)
62 v = CRC_UPDATE_BYTE_2(v, *p);
63 return v;
64 }
65
66 #endif
67