34cf4058 |
1 | #include "Types.h" |
2 | |
3 | #define CRC32_POLYNOMIAL 0x04C11DB7 |
4 | |
5 | #ifdef __CRC_OPT |
6 | unsigned int CRCTable[ 256 * 4]; |
7 | #else |
8 | unsigned int CRCTable[ 256 ]; |
9 | #endif |
10 | |
11 | u32 Reflect( u32 ref, char ch ) |
12 | { |
13 | u32 value = 0; |
14 | |
15 | // Swap bit 0 for bit 7 |
16 | // bit 1 for bit 6, etc. |
17 | for (int i = 1; i < (ch + 1); i++) |
18 | { |
19 | if(ref & 1) |
20 | value |= 1 << (ch - i); |
21 | ref >>= 1; |
22 | } |
23 | return value; |
24 | } |
25 | |
26 | void CRC_BuildTable() |
27 | { |
28 | u32 crc; |
29 | |
30 | for (int i = 0; i < 256; i++) |
31 | { |
32 | crc = Reflect( i, 8 ) << 24; |
33 | for (int j = 0; j < 8; j++) |
34 | crc = (crc << 1) ^ (crc & (1 << 31) ? CRC32_POLYNOMIAL : 0); |
35 | |
36 | CRCTable[i] = Reflect( crc, 32 ); |
37 | } |
38 | |
39 | #ifdef __CRC_OPT |
40 | for (int i = 0; i < 256; i++) |
41 | { |
42 | for(int j = 0; j < 3; j++) |
43 | { |
44 | CRCTable[256*(j+1) + i] = (CRCTable[256*j + i]>>8) ^ CRCTable[CRCTable[256*j + i]&0xFF]; |
45 | } |
46 | } |
47 | #endif |
48 | |
49 | } |
50 | |
51 | u32 CRC_Calculate( u32 crc, void *buffer, u32 count ) |
52 | { |
53 | u8 *p; |
54 | u32 orig = crc; |
55 | |
56 | p = (u8*) buffer; |
57 | |
58 | #ifdef __CRC_OPT |
59 | while(count > 3) |
60 | { |
61 | crc ^= *(unsigned int*) p; p += 4; |
62 | crc = CRCTable[3*256 + (crc&0xFF)] |
63 | ^ CRCTable[2*256 + ((crc>>8)&0xFF)] |
64 | ^ CRCTable[1*256 + ((crc>>16)&0xFF)] |
65 | ^ CRCTable[0*256 + ((crc>>24))]; |
66 | |
67 | count -= 4; |
68 | } |
69 | #endif |
70 | |
71 | while (count--) |
72 | crc = (crc >> 8) ^ CRCTable[(crc & 0xFF) ^ *p++]; |
73 | |
74 | return crc ^ orig; |
75 | } |
76 | |
77 | u32 CRC_CalculatePalette( u32 crc, void *buffer, u32 count ) |
78 | { |
79 | u8 *p; |
80 | u32 orig = crc; |
81 | |
82 | p = (u8*) buffer; |
83 | while (count--) |
84 | { |
85 | crc = (crc >> 8) ^ CRCTable[(crc & 0xFF) ^ *p++]; |
86 | crc = (crc >> 8) ^ CRCTable[(crc & 0xFF) ^ *p++]; |
87 | |
88 | p += 6; |
89 | } |
90 | |
91 | return crc ^ orig; |
92 | } |
93 | |