1 /* 7zCrc.c -- CRC32 init
2 2015-03-10 : Igor Pavlov : Public domain */
3
4 #include "Precomp.h"
5
6 #include "7zCrc.h"
7 #include "CpuArch.h"
8
9 #define kCrcPoly 0xEDB88320
10
11 #ifdef MY_CPU_LE
12 #define CRC_NUM_TABLES 8
13 #else
14 #define CRC_NUM_TABLES 9
15
16 #define CRC_UINT32_SWAP(v) ((v >> 24) | ((v >> 8) & 0xFF00) | ((v << 8) & 0xFF0000) | (v << 24))
17
18 UInt32 MY_FAST_CALL CrcUpdateT1_BeT4(UInt32 v, const void *data, size_t size, const UInt32 *table);
19 UInt32 MY_FAST_CALL CrcUpdateT1_BeT8(UInt32 v, const void *data, size_t size, const UInt32 *table);
20 #endif
21
22 #ifndef MY_CPU_BE
23 UInt32 MY_FAST_CALL CrcUpdateT4(UInt32 v, const void *data, size_t size, const UInt32 *table);
24 UInt32 MY_FAST_CALL CrcUpdateT8(UInt32 v, const void *data, size_t size, const UInt32 *table);
25 #endif
26
27 typedef UInt32 (MY_FAST_CALL *CRC_FUNC)(UInt32 v, const void *data, size_t size, const UInt32 *table);
28
29 CRC_FUNC g_CrcUpdateT4;
30 CRC_FUNC g_CrcUpdateT8;
31 CRC_FUNC g_CrcUpdate;
32
33 UInt32 g_CrcTable[256 * CRC_NUM_TABLES];
34
CrcUpdate(UInt32 v,const void * data,size_t size)35 UInt32 MY_FAST_CALL CrcUpdate(UInt32 v, const void *data, size_t size)
36 {
37 return g_CrcUpdate(v, data, size, g_CrcTable);
38 }
39
CrcCalc(const void * data,size_t size)40 UInt32 MY_FAST_CALL CrcCalc(const void *data, size_t size)
41 {
42 return g_CrcUpdate(CRC_INIT_VAL, data, size, g_CrcTable) ^ CRC_INIT_VAL;
43 }
44
45 #define CRC_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8))
46
CrcUpdateT1(UInt32 v,const void * data,size_t size,const UInt32 * table)47 UInt32 MY_FAST_CALL CrcUpdateT1(UInt32 v, const void *data, size_t size, const UInt32 *table)
48 {
49 const Byte *p = (const Byte *)data;
50 const Byte *pEnd = p + size;
51 for (; p != pEnd; p++)
52 v = CRC_UPDATE_BYTE_2(v, *p);
53 return v;
54 }
55
CrcGenerateTable()56 void MY_FAST_CALL CrcGenerateTable()
57 {
58 UInt32 i;
59 for (i = 0; i < 256; i++)
60 {
61 UInt32 r = i;
62 unsigned j;
63 for (j = 0; j < 8; j++)
64 r = (r >> 1) ^ (kCrcPoly & ~((r & 1) - 1));
65 g_CrcTable[i] = r;
66 }
67 for (; i < 256 * CRC_NUM_TABLES; i++)
68 {
69 UInt32 r = g_CrcTable[i - 256];
70 g_CrcTable[i] = g_CrcTable[r & 0xFF] ^ (r >> 8);
71 }
72
73 #if CRC_NUM_TABLES < 4
74
75 g_CrcUpdate = CrcUpdateT1;
76
77 #else
78
79 #ifdef MY_CPU_LE
80
81 g_CrcUpdateT4 = CrcUpdateT4;
82 g_CrcUpdate = CrcUpdateT4;
83
84 #if CRC_NUM_TABLES >= 8
85 g_CrcUpdateT8 = CrcUpdateT8;
86
87 #ifdef MY_CPU_X86_OR_AMD64
88 if (!CPU_Is_InOrder())
89 g_CrcUpdate = CrcUpdateT8;
90 #endif
91 #endif
92
93 #else
94 {
95 #ifndef MY_CPU_BE
96 UInt32 k = 0x01020304;
97 const Byte *p = (const Byte *)&k;
98 if (p[0] == 4 && p[1] == 3)
99 {
100 g_CrcUpdateT4 = CrcUpdateT4;
101 g_CrcUpdate = CrcUpdateT4;
102 #if CRC_NUM_TABLES >= 8
103 g_CrcUpdateT8 = CrcUpdateT8;
104 // g_CrcUpdate = CrcUpdateT8;
105 #endif
106 }
107 else if (p[0] != 1 || p[1] != 2)
108 g_CrcUpdate = CrcUpdateT1;
109 else
110 #endif
111 {
112 for (i = 256 * CRC_NUM_TABLES - 1; i >= 256; i--)
113 {
114 UInt32 x = g_CrcTable[i - 256];
115 g_CrcTable[i] = CRC_UINT32_SWAP(x);
116 }
117 g_CrcUpdateT4 = CrcUpdateT1_BeT4;
118 g_CrcUpdate = CrcUpdateT1_BeT4;
119 #if CRC_NUM_TABLES >= 8
120 g_CrcUpdateT8 = CrcUpdateT1_BeT8;
121 // g_CrcUpdate = CrcUpdateT1_BeT8;
122 #endif
123 }
124 }
125 #endif
126
127 #endif
128 }
129