1 /* XzCrc64.c -- CRC64 calculation
2 2023-04-02 : Igor Pavlov : Public domain */
3
4 #include "Precomp.h"
5
6 #include "XzCrc64.h"
7 #include "CpuArch.h"
8
9 #define kCrc64Poly UINT64_CONST(0xC96C5795D7870F42)
10
11 #ifdef MY_CPU_LE
12 #define CRC64_NUM_TABLES 4
13 #else
14 #define CRC64_NUM_TABLES 5
15
16 UInt64 Z7_FASTCALL XzCrc64UpdateT1_BeT4(UInt64 v, const void *data, size_t size, const UInt64 *table);
17 #endif
18
19 #ifndef MY_CPU_BE
20 UInt64 Z7_FASTCALL XzCrc64UpdateT4(UInt64 v, const void *data, size_t size, const UInt64 *table);
21 #endif
22
23 typedef UInt64 (Z7_FASTCALL *CRC64_FUNC)(UInt64 v, const void *data, size_t size, const UInt64 *table);
24
25 static CRC64_FUNC g_Crc64Update;
26 UInt64 g_Crc64Table[256 * CRC64_NUM_TABLES];
27
Crc64Update(UInt64 v, const void *data, size_t size)28 UInt64 Z7_FASTCALL Crc64Update(UInt64 v, const void *data, size_t size)
29 {
30 return g_Crc64Update(v, data, size, g_Crc64Table);
31 }
32
Crc64Calc(const void *data, size_t size)33 UInt64 Z7_FASTCALL Crc64Calc(const void *data, size_t size)
34 {
35 return g_Crc64Update(CRC64_INIT_VAL, data, size, g_Crc64Table) ^ CRC64_INIT_VAL;
36 }
37
Crc64GenerateTable(void)38 void Z7_FASTCALL Crc64GenerateTable(void)
39 {
40 UInt32 i;
41 for (i = 0; i < 256; i++)
42 {
43 UInt64 r = i;
44 unsigned j;
45 for (j = 0; j < 8; j++)
46 r = (r >> 1) ^ (kCrc64Poly & ((UInt64)0 - (r & 1)));
47 g_Crc64Table[i] = r;
48 }
49 for (i = 256; i < 256 * CRC64_NUM_TABLES; i++)
50 {
51 const UInt64 r = g_Crc64Table[(size_t)i - 256];
52 g_Crc64Table[i] = g_Crc64Table[r & 0xFF] ^ (r >> 8);
53 }
54
55 #ifdef MY_CPU_LE
56
57 g_Crc64Update = XzCrc64UpdateT4;
58
59 #else
60 {
61 #ifndef MY_CPU_BE
62 UInt32 k = 1;
63 if (*(const Byte *)&k == 1)
64 g_Crc64Update = XzCrc64UpdateT4;
65 else
66 #endif
67 {
68 for (i = 256 * CRC64_NUM_TABLES - 1; i >= 256; i--)
69 {
70 const UInt64 x = g_Crc64Table[(size_t)i - 256];
71 g_Crc64Table[i] = Z7_BSWAP64(x);
72 }
73 g_Crc64Update = XzCrc64UpdateT1_BeT4;
74 }
75 }
76 #endif
77 }
78
79 #undef kCrc64Poly
80 #undef CRC64_NUM_TABLES
81