Писал сам, хотя эффективнее использовать уже готовый алгоритм, но все же насколько пригоден мой код?
#include "stdafx.h"
#define POLY 46208
#define REMAIN 7
#define SIZE_BLOCK 1024
// Russain messages programm ->
#define MESSAGE_SYSTEM L"Блок CRC "
#define MESSAGE_HELP L"Не введены параметры!\nИспользуйте crc.exe [путь] \
имя_файла \nНапример: crc.exe C:\\file.dat\n"
#define MESSAGE_ABOUT L" "
#define MESSAGE_ERROR L"Не возможно открыть файл!\n"
#define MESSAGE_WARNING L"Файл слишком маленького размера!\n"
// <- Russain messages programm
unsigned char ReadBit(unsigned short Data, unsigned char Index)
{
const char digit = sizeof(Data)*8-1;
return (unsigned char)(Data <<= (digit - Index), Data >>= digit);
}
unsigned char ShiftZero(unsigned short &Data)
{
char digit = sizeof(Data)*8-1;
unsigned char ReadBits = 0;
for(int i = digit; i>=0; --i)
{
ReadBits = ReadBit(Data, i);
if(ReadBits)
{
int Shift = digit - i;
Data <<= Shift;
return Shift;
}
}
return ++digit;
}
void BitCopy(const unsigned short &Source,
unsigned short &Target,
const char Index,
const char Size)
{
unsigned char ReadBits = 0;
char Limit = Index-Size;
for(int i = Index; i>Limit; --i)
{
char IndexBit = (Size-1) - (Index-i);
ReadBits = ReadBit(Source, i);
if (ReadBits)
Target |= (1 << (IndexBit));
else
Target &= ~(1 << (IndexBit));
}
}
unsigned char DevMod2(unsigned short *Data, unsigned int SizeWords)
{
const char BitSize = sizeof(*Data)*8-1;
char IndexBit = BitSize,
NumShift = 0,
MaxLimit = 0,
CheckLimit = 0;
int IndexWord = SizeWords - 1;
unsigned short WorkArea = Data[IndexWord--],
Differ = 0,
WorkTemp = 0;
bool Loop = true;
while(Loop)
{
WorkArea ^= POLY;
WorkTemp = WorkArea;
NumShift = ShiftZero(WorkTemp);
if(!NumShift)
continue;
if(IndexWord >= 0)
{
WorkArea = WorkTemp;
CheckLimit = IndexBit-NumShift;
if (CheckLimit >= -1)
{
BitCopy(Data[IndexWord], WorkArea, IndexBit, NumShift);
IndexBit = CheckLimit;
if(IndexBit == -1){ IndexBit = 15; --IndexWord;}
}
else
{
BitCopy(Data[IndexWord], Differ, IndexBit, ++IndexBit);
if(IndexWord > 0)
{
char TempDef = NumShift - IndexBit;
IndexBit = BitSize;
Differ <<= TempDef;
BitCopy(Data[--IndexWord], Differ, IndexBit, TempDef);
IndexBit -= TempDef;
}
WorkArea |= Differ;
Differ = 0;
}
}
else
{
MaxLimit += NumShift;
if(MaxLimit > REMAIN)
Loop = false;
else
WorkArea = WorkTemp;
}
}
WorkArea >>= REMAIN;
return (unsigned char) WorkArea;
}
void RussianPrint(const wchar_t *lText)
{
std::wcout.imbue(std::locale(".866"));
std::wcout << lText;
}
int _tmain(int argc, _TCHAR* argv[])
{
unsigned char Buffer[SIZE_BLOCK];
unsigned char Result = 0;
const long LocalBlockSize = SIZE_BLOCK/sizeof(short);
if (argc == 1)
{
RussianPrint(MESSAGE_HELP);
RussianPrint(MESSAGE_ABOUT);
return 0;
}
FILE *Crc = fopen(argv[1], "rb");
if(!Crc)
{
RussianPrint(MESSAGE_ERROR);
return 0;
}
fseek(Crc, 0, SEEK_END);
long NumOfBlock = ftell(Crc) / SIZE_BLOCK;
fseek(Crc, 0, SEEK_SET);
if(!NumOfBlock)
RussianPrint(MESSAGE_WARNING);
for(int i=0; i<NumOfBlock; ++i)
{
fread(Buffer, sizeof(char), SIZE_BLOCK, Crc);
Result = DevMod2((unsigned short*)Buffer, LocalBlockSize);
RussianPrint(MESSAGE_SYSTEM);
std::cout << std::dec << i+1 << ": " << std::hex
<< (int)Result << std::endl;
}
fclose(Crc);
return 0;
}
Перед использованием GetCRC() или FileCRC() необходимо вызвать InitCRC()
DWORD crctable[256];
DWORD MemSize=65536; //Memory usage
#define CRCPOLY 0xEDB88320
#define CRC_MASK 0xFFFFFFFF
DWORD WINAPI FileCRC(LPCTSTR szFileName);
void WINAPI InitCRC();
DWORD WINAPI GetCRC(DWORD crc, BYTE *addr, DWORD len);
DWORD WINAPI FileCRC(LPCTSTR szFileName)
{
HANDLE hFile=INVALID_HANDLE_VALUE;
HANDLE hMapping=NULL;
LPVOID lpFile=NULL;
BYTE* p=NULL;
DWORD retval=CRC_MASK;
DWORD hSize=0;
DWORD lSize=0;
DWORD BytesToProcess=0;
__int64 FileOffset=0;
__int64 FileSize=0;
__try
{
hFile=CreateFile(szFileName, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_FLAG_SEQUENTIAL_SCAN, NULL);
if (hFile==INVALID_HANDLE_VALUE)
__leave;
lSize=GetFileSize(hFile, &hSize);
if (lSize==0 && hSize==0)
__leave;
FileSize=(__int64)lSize+(__int64)(((__int64)hSize) << 32);
hMapping=CreateFileMapping(hFile, NULL, PAGE_READONLY, 0, 0, NULL);
if (hMapping==NULL)
__leave;
while (FileSize>0)
{
if (FileSize < MemSize)
BytesToProcess=(DWORD)FileSize;
else
BytesToProcess=MemSize;
lpFile=MapViewOfFile(hMapping, FILE_MAP_READ, (DWORD)(FileOffset >> 32), (DWORD)(FileOffset & 0xFFFFFFFF), BytesToProcess);
if (lpFile==NULL)
__leave;
p=(BYTE*)lpFile;
retval=GetCRC(retval, p, BytesToProcess);
UnmapViewOfFile(lpFile);
lpFile=NULL;
FileOffset+=BytesToProcess;
FileSize-=BytesToProcess;
}
}
__finally
{
if (lpFile!=NULL)
{
UnmapViewOfFile(lpFile);
lpFile=NULL;
}
if (hMapping!=NULL)
{
CloseHandle(hMapping);
hMapping=NULL;
}
if (hFile!=INVALID_HANDLE_VALUE)
{
CloseHandle(hFile);
hFile=INVALID_HANDLE_VALUE;
}
}
return (retval^CRC_MASK);
}
void WINAPI InitCRC()
{
DWORD r,i,j;
for (i=0;i<=255;i++)
{
for (r=i,j=8;j;j--)
{
r=(r&1)?(r>>1)^CRCPOLY:(r>>1);
}
crctable[i] = r;
}
}
DWORD WINAPI GetCRC(DWORD crc, BYTE *addr, DWORD len)
{
while (len--)
crc=crctable[(BYTE)crc^(*addr++)]^(crc>>8);
return crc;
}
Здравствуйте, grigsoft, Вы писали:
G>Готовую таблицу обычно встраивают прямо в код.
const DWORD crctable[256]={
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};
