Code:
unsigned long IntArray[]={
0x00000000,
0x77073096,
0xEE0E612C,
0x990951BA,
0x076DC419,
0x706AF48F,
0xE963A535,
0x9E6495A3,
0x0EDB8832,
0x79DCB8A4,
0xE0D5E91E,
0x97D2D988,
0x09B64C2B,
0x7EB17CBD,
0xE7B82D07,
0x90BF1D91,
0x1DB71064,
0x6AB020F2,
0xF3B97148,
0x84BE41DE,
0x1ADAD47D,
0x6DDDE4EB,
0xF4D4B551,
0x83D385C7,
0x136C9856,
0x646BA8C0,
0xFD62F97A,
0x8A65C9EC,
0x14015C4F,
0x63066CD9,
0xFA0F3D63,
0x8D080DF5,
0x3B6E20C8,
0x4C69105E,
0xD56041E4,
0xA2677172,
0x3C03E4D1,
0x4B04D447,
0xD20D85FD,
0xA50AB56B,
0x35B5A8FA,
0x42B2986C,
0xDBBBC9D6,
0xACBCF940,
0x32D86CE3,
0x45DF5C75,
0xDCD60DCF,
0xABD13D59,
0x26D930AC,
0x51DE003A,
0xC8D75180,
0xBFD06116,
0x21B4F4B5,
0x56B3C423,
0xCFBA9599,
0xB8BDA50F,
0x2802B89E,
0x5F058808,
0xC60CD9B2,
0xB10BE924,
0x2F6F7C87,
0x58684C11,
0xC1611DAB,
0xB6662D3D,
0x76DC4190,
0x01DB7106,
0x98D220BC,
0xEFD5102A,
0x71B18589,
0x06B6B51F,
0x9FBFE4A5,
0xE8B8D433,
0x7807C9A2,
0x0F00F934,
0x9609A88E,
0xE10E9818,
0x7F6A0DBB,
0x086D3D2D,
0x91646C97,
0xE6635C01,
0x6B6B51F4,
0x1C6C6162,
0x856530D8,
0xF262004E,
0x6C0695ED,
0x1B01A57B,
0x8208F4C1,
0xF50FC457,
0x65B0D9C6,
0x12B7E950,
0x8BBEB8EA,
0xFCB9887C,
0x62DD1DDF,
0x15DA2D49,
0x8CD37CF3,
0xFBD44C65,
0x4DB26158,
0x3AB551CE,
0xA3BC0074,
0xD4BB30E2,
0x4ADFA541,
0x3DD895D7,
0xA4D1C46D,
0xD3D6F4FB,
0x4369E96A,
0x346ED9FC,
0xAD678846,
0xDA60B8D0,
0x44042D73,
0x33031DE5,
0xAA0A4C5F,
0xDD0D7CC9,
0x5005713C,
0x270241AA,
0xBE0B1010,
0xC90C2086,
0x5768B525,
0x206F85B3,
0xB966D409,
0xCE61E49F,
0x5EDEF90E,
0x29D9C998,
0xB0D09822,
0xC7D7A8B4,
0x59B33D17,
0x2EB40D81,
0xB7BD5C3B,
0xC0BA6CAD,
0xEDB88320,
0x9ABFB3B6,
0x03B6E20C,
0x74B1D29A,
0xEAD54739,
0x9DD277AF,
0x04DB2615,
0x73DC1683,
0xE3630B12,
0x94643B84,
0x0D6D6A3E,
0x7A6A5AA8,
0xE40ECF0B,
0x9309FF9D,
0x0A00AE27,
0x7D079EB1,
0xF00F9344,
0x8708A3D2,
0x1E01F268,
0x6906C2FE,
0xF762575D,
0x806567CB,
0x196C3671,
0x6E6B06E7,
0xFED41B76,
0x89D32BE0,
0x10DA7A5A,
0x67DD4ACC,
0xF9B9DF6F,
0x8EBEEFF9,
0x17B7BE43,
0x60B08ED5,
0xD6D6A3E8,
0xA1D1937E,
0x38D8C2C4,
0x4FDFF252,
0xD1BB67F1,
0xA6BC5767,
0x3FB506DD,
0x48B2364B,
0xD80D2BDA,
0xAF0A1B4C,
0x36034AF6,
0x41047A60,
0xDF60EFC3,
0xA867DF55,
0x316E8EEF,
0x4669BE79,
0xCB61B38C,
0xBC66831A,
0x256FD2A0,
0x5268E236,
0xCC0C7795,
0xBB0B4703,
0x220216B9,
0x5505262F,
0xC5BA3BBE,
0xB2BD0B28,
0x2BB45A92,
0x5CB36A04,
0xC2D7FFA7,
0xB5D0CF31,
0x2CD99E8B,
0x5BDEAE1D,
0x9B64C2B0,
0xEC63F226,
0x756AA39C,
0x026D930A,
0x9C0906A9,
0xEB0E363F,
0x72076785,
0x05005713,
0x95BF4A82,
0xE2B87A14,
0x7BB12BAE,
0x0CB61B38,
0x92D28E9B,
0xE5D5BE0D,
0x7CDCEFB7,
0x0BDBDF21,
0x86D3D2D4,
0xF1D4E242,
0x68DDB3F8,
0x1FDA836E,
0x81BE16CD,
0xF6B9265B,
0x6FB077E1,
0x18B74777,
0x88085AE6,
0xFF0F6A70,
0x66063BCA,
0x11010B5C,
0x8F659EFF,
0xF862AE69,
0x616BFFD3,
0x166CCF45,
0xA00AE278,
0xD70DD2EE,
0x4E048354,
0x3903B3C2,
0xA7672661,
0xD06016F7,
0x4969474D,
0x3E6E77DB,
0xAED16A4A,
0xD9D65ADC,
0x40DF0B66,
0x37D83BF0,
0xA9BCAE53,
0xDEBB9EC5,
0x47B2CF7F,
0x30B5FFE9,
0xBDBDF21C,
0xCABAC28A,
0x53B39330,
0x24B4A3A6,
0xBAD03605,
0xCDD70693,
0x54DE5729,
0x23D967BF,
0xB3667A2E,
0xC4614AB8,
0x5D681B02,
0x2A6F2B94,
0xB40BBE37,
0xC30C8EA1,
0x5A05DF1B,
0x2D02EF8D,
};
unsigned long myCRC(unsigned char *buf, int size, int key)
{
/*
sub_0_10020760 proc near ; CODE XREF: sub_0_10008620+AEp
; sub_0_10022A90+14Fp ...
arg_0 = dword ptr 4
arg_4 = dword ptr 8
arg_8 = dword ptr 0Ch
*/
//int *pecx = buf;
int ecx = key; //mov ecx, [esp+arg_8]
int eax = ecx; //mov eax, ecx
eax~=eax; //not eax
eax&=0xFF; //and eax, 0FFh
eax=IntArray[eax]; //mov eax, dword_0_10115D38[eax*4] IntArray
eax ^= 0x00FFFFFF; //xor eax, 0FFFFFFh
int edx = ecx; //mov edx, ecx
edx = edx >> 8; //sar edx, 8
edx = edx ^ eax; //xor edx, eax
eax = eax >> 8; //sar eax, 8
edx &= 0xFF; //and edx, 0FFh
eax &= 0x00FFFFFF; //and eax, 0FFFFFFh
//push esi
eax ^= IntArray[edx]; //xor eax, dword_0_10115D38[edx*4]
edx = ecx; //mov edx, ecx
edx = edx >> 0x10; //sar edx, 10h
edx ^= eax; //xor edx, eax
eax = eax >> 8; //sar eax, 8
edx &= 0xFF; //and edx, 0FFh
int esi = IntArray[edx]; //mov esi, dword_0_10115D38[edx*4]
edx = size; //mov edx, [esp+4+arg_4]
eax &= 0x00FFFFFF; //and eax, 0FFFFFFh
eax ^= esi; //xor eax, esi
ecx = ecx >> 0x18; //sar ecx, 18h
ecx ^= eax; //xor ecx, eax
ecx &= 0xFF; //and ecx, 0FFh
esi = IntArray[ecx]; //mov esi, dword_0_10115D38[ecx*4]
// ecx = buf; //mov ecx, [esp+4+arg_0]
eax = eax >> 8; //sar eax, 8
eax &= 0x00FFFFFF; //and eax, 0FFFFFFh
eax ^= esi; //xor eax, esi
/* int* esi = ecx+edx //??*///lea esi, [ecx+edx]
for(int x = 0; x < size; x++)
{ //eax is the crc, ecx is the current part of the buffer
int edx = 0; //xor edx, edx
edx = buf[x] & 0x00FF; //mov dl, [ecx]
/*if(pos > size) //cmp ecx, esi
return ~eax; //jnb short loc_0_10020803
*/
//push edi
//loc_0_100207E0: ; CODE XREF: sub_0_10020760+A0j //LOOP
edx ^= eax; //xor edx, eax
eax = eax >> 8; //sar eax, 8
edx &= 0xFF; //and edx, 0FFh
edi = IntArray[edx]; //mov edi, dword_0_10115D38[edx*4]
eax &= 0x00FFFFFF; //and eax, 0FFFFFFh
eax ^= edi; //xor eax, edi
//inc ecx
//cmp ecx, esi
// jb short loc_0_100207E0
//pop edi
}
return ~eax;
}
/*loc_0_10020803: ; CODE XREF: sub_0_10020760+7Dj
not eax
pop esi
retn
sub_0_10020760 endp
*/
I never did finish that before my accident.. I'm not sure it works but that IS the function that is called. I had completely forgot about it until now. Also the forums apparently screwed up my indentation.
Edit: Yes, this will generate a 32 bit number, it is either ah or al of it that is used depending.