内联汇编的快速CRC32

typedef unsigned __int64 QWORD;

class  CCrc32Static
... {
public:
    CCrc32Static()...{};
    virtual ~CCrc32Static()...{};
    static DWORD StringCrc32(LPCTSTR szString, DWORD &dwCrc32);
    static DWORD FileCrc32Assembly(LPCTSTR szFilename, DWORD &dwCrc32);
protected:
    static inline void CalcCrc32(const BYTE byte, DWORD &dwCrc32);
    static DWORD s_arrdwCrc32Table[256];
} ;

#define  MAX_BUFFER_SIZE 4096
// #define MAKEQWORD(a, b) ((WORD)(((BYTE)((DWORD_PTR)(a) & 0xffffffffffffffff)) | ((WORD)((BYTE)((DWORD_PTR)(b) & 0xffffffffffffffff))) << 64))

    //Powered by barenx
// #define INVALID_HANDLE_VALUE ((HANDLE)(-1))   
//  Static CRC table
DWORD CCrc32Static::s_arrdwCrc32Table[ 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,
} ;

inline  void  CCrc32Static::CalcCrc32( const  BYTE  byte , DWORD  & dwCrc32)
... {
    dwCrc32 = ((dwCrc32) >> 8) ^ s_arrdwCrc32Table[(byte) ^ ((dwCrc32) & 0x000000FF)];
}

DWORD CCrc32Static::StringCrc32(LPCTSTR szString, DWORD  & dwCrc32)
... {
    DWORD dwErrorCode = NO_ERROR;
    dwCrc32 = 0xFFFFFFFF;
    while(*szString != NULL)
    ...{
        CalcCrc32((BYTE)*szString, dwCrc32);
        szString++;
    }
    dwCrc32 = ~dwCrc32;
    return 0;
}

DWORD CCrc32Static::FileCrc32Assembly(LPCTSTR szFilename, DWORD  & dwCrc32)
... {
    DWORD dwErrorCode = NO_ERROR;
    HANDLE hFile = NULL;
    dwCrc32 = 0xFFFFFFFF;
    try
    ...{
        // Open the file
        hFile = CreateFile(szFilename,
            GENERIC_READ,
            FILE_SHARE_READ,
            NULL,
            OPEN_EXISTING,
            FILE_ATTRIBUTE_ARCHIVE | FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_READONLY | FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_SEQUENTIAL_SCAN,
            NULL);
        if(hFile == INVALID_HANDLE_VALUE)
            dwErrorCode = GetLastError();
        else
        ...{
            // There is a bug in the Microsoft compilers where inline assembly
            // code cannot access static member variables.  This is a work around
            // for that bug.  For more info see Knowledge base article Q88092
            LPVOID ptrCrc32Table = &s_arrdwCrc32Table;

            BYTE buffer[MAX_BUFFER_SIZE];
            DWORD dwBytesRead;
            BOOL bSuccess = ReadFile(hFile, buffer, sizeof(buffer), &dwBytesRead, NULL);
            while(bSuccess && dwBytesRead)
            ...{
                // Register use:
                // eax - CRC32 value
                // ebx - a lot of things
                // ecx - CRC32 value
                // edx - address of end of buffer
                // esi - address of start of buffer
                // edi - CRC32 table
                __asm
                ...{
                    // Save the esi and edi registers
                    push esi
                    push edi

                    mov eax, dwCrc32 // Load the pointer to dwCrc32
                    mov ecx, [eax] // Dereference the pointer to load dwCrc32

                    mov edi, ptrCrc32Table // Load the CRC32 table

                    lea esi, buffer // Load buffer
                    mov ebx, dwBytesRead // Load dwBytesRead
                    lea edx, [esi + ebx] // Calculate the end of the buffer

                    crc32loop:
                    xor eax, eax // Clear the eax register
                    mov bl, byte ptr [esi] // Load the current source byte

                    mov al, cl // Copy crc value into eax
                    inc esi // Advance the source pointer

                    xor al, bl // Create the index into the CRC32 table
                    shr ecx, 8

                    mov ebx, [edi + eax * 4] // Get the value out of the table
                    xor ecx, ebx // xor with the current byte

                    cmp edx, esi // Have we reached the end of the buffer?
                    jne crc32loop

                    // Restore the edi and esi registers
                    pop edi
                    pop esi

                    mov eax, dwCrc32 // Load the pointer to dwCrc32
                    mov [eax], ecx // Write the result
                }
                bSuccess = ReadFile(hFile, buffer, sizeof(buffer), &dwBytesRead, NULL);
            }
        }
    }
    catch(...)
    ...{
        dwErrorCode = ERROR_CRC;        // An unknown exception happened
    }
    if(hFile != NULL) CloseHandle(hFile);
    dwCrc32 = ~dwCrc32;
    return dwErrorCode;
}