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1 /* 7zCrcOpt.c -- CRC32 calculation
2 2017-04-03 : Igor Pavlov : Public domain */
3 
4 #include "Precomp.h"
5 
6 #include "CpuArch.h"
7 
8 #ifndef MY_CPU_BE
9 
10 #define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8))
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   const Byte *p = (const Byte *)data;
34   for (; size > 0 && ((unsigned)(ptrdiff_t)p & 7) != 0; size--, p++)
35     v = CRC_UPDATE_BYTE_2(v, *p);
36   for (; size >= 8; size -= 8, p += 8)
37   {
38     UInt32 d;
39     v ^= *(const UInt32 *)p;
40     v =
41           (table + 0x700)[((v      ) & 0xFF)]
42         ^ (table + 0x600)[((v >>  8) & 0xFF)]
43         ^ (table + 0x500)[((v >> 16) & 0xFF)]
44         ^ (table + 0x400)[((v >> 24))];
45     d = *((const UInt32 *)p + 1);
46     v ^=
47           (table + 0x300)[((d      ) & 0xFF)]
48         ^ (table + 0x200)[((d >>  8) & 0xFF)]
49         ^ (table + 0x100)[((d >> 16) & 0xFF)]
50         ^ (table + 0x000)[((d >> 24))];
51   }
52   for (; size > 0; size--, p++)
53     v = CRC_UPDATE_BYTE_2(v, *p);
54   return v;
55 }
56 
57 #endif
58 
59 
60 #ifndef MY_CPU_LE
61 
62 #define CRC_UINT32_SWAP(v) ((v >> 24) | ((v >> 8) & 0xFF00) | ((v << 8) & 0xFF0000) | (v << 24))
63 
64 #define CRC_UPDATE_BYTE_2_BE(crc, b) (table[(((crc) >> 24) ^ (b))] ^ ((crc) << 8))
65 
CrcUpdateT1_BeT4(UInt32 v,const void * data,size_t size,const UInt32 * table)66 UInt32 MY_FAST_CALL CrcUpdateT1_BeT4(UInt32 v, const void *data, size_t size, const UInt32 *table)
67 {
68   const Byte *p = (const Byte *)data;
69   table += 0x100;
70   v = CRC_UINT32_SWAP(v);
71   for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
72     v = CRC_UPDATE_BYTE_2_BE(v, *p);
73   for (; size >= 4; size -= 4, p += 4)
74   {
75     v ^= *(const UInt32 *)p;
76     v =
77           (table + 0x000)[((v      ) & 0xFF)]
78         ^ (table + 0x100)[((v >>  8) & 0xFF)]
79         ^ (table + 0x200)[((v >> 16) & 0xFF)]
80         ^ (table + 0x300)[((v >> 24))];
81   }
82   for (; size > 0; size--, p++)
83     v = CRC_UPDATE_BYTE_2_BE(v, *p);
84   return CRC_UINT32_SWAP(v);
85 }
86 
CrcUpdateT1_BeT8(UInt32 v,const void * data,size_t size,const UInt32 * table)87 UInt32 MY_FAST_CALL CrcUpdateT1_BeT8(UInt32 v, const void *data, size_t size, const UInt32 *table)
88 {
89   const Byte *p = (const Byte *)data;
90   table += 0x100;
91   v = CRC_UINT32_SWAP(v);
92   for (; size > 0 && ((unsigned)(ptrdiff_t)p & 7) != 0; size--, p++)
93     v = CRC_UPDATE_BYTE_2_BE(v, *p);
94   for (; size >= 8; size -= 8, p += 8)
95   {
96     UInt32 d;
97     v ^= *(const UInt32 *)p;
98     v =
99           (table + 0x400)[((v      ) & 0xFF)]
100         ^ (table + 0x500)[((v >>  8) & 0xFF)]
101         ^ (table + 0x600)[((v >> 16) & 0xFF)]
102         ^ (table + 0x700)[((v >> 24))];
103     d = *((const UInt32 *)p + 1);
104     v ^=
105           (table + 0x000)[((d      ) & 0xFF)]
106         ^ (table + 0x100)[((d >>  8) & 0xFF)]
107         ^ (table + 0x200)[((d >> 16) & 0xFF)]
108         ^ (table + 0x300)[((d >> 24))];
109   }
110   for (; size > 0; size--, p++)
111     v = CRC_UPDATE_BYTE_2_BE(v, *p);
112   return CRC_UINT32_SWAP(v);
113 }
114 
115 #endif
116