#include "stdafx.h"
#include "Crc32Dynamic.h"
#include <fstream.h>
//***********************************************
CCrc32Dynamic::CCrc32Dynamic() : m_pdwCrc32Table(NULL)
{
}
//***********************************************
CCrc32Dynamic::~CCrc32Dynamic()
{
Free();
}
//***********************************************
void CCrc32Dynamic::Init(void)
{
// This is the official polynomial used by CRC32 in PKZip.
// Often times the polynomial shown reversed as 0x04C11DB7.
DWORD dwPolynomial = 0xEDB88320;
int i, j;
Free();
m_pdwCrc32Table = new DWORD[256];
DWORD dwCrc;
for(i = 0; i < 256; i++)
{
dwCrc = i;
for(j = 8; j > 0; j--)
{
if(dwCrc & 1)
dwCrc = (dwCrc >> 1) ^ dwPolynomial;
else
dwCrc >>= 1;
}
m_pdwCrc32Table[i] = dwCrc;
}
}
//***********************************************
void CCrc32Dynamic::Free(void)
{
delete m_pdwCrc32Table;
m_pdwCrc32Table = NULL;
}
//***********************************************
inline void CCrc32Dynamic::CalcCrc32(const BYTE byte, DWORD &dwCrc32) const
{
dwCrc32 = ((dwCrc32) >> 8) ^ m_pdwCrc32Table[(byte) ^ ((dwCrc32) & 0x000000FF)];
}
//***********************************************
bool CCrc32Dynamic::GetFileSizeQW(const HANDLE hFile, QWORD &qwSize)
{
_ASSERTE(hFile != INVALID_HANDLE_VALUE);
bool bSuccess = true;
try
{
DWORD dwLo = 0, dwHi = 0;
dwLo = GetFileSize(hFile, &dwHi);
if(dwLo == INVALID_FILE_SIZE && GetLastError() != NO_ERROR)
{
bSuccess = false;
qwSize = 0;
}
else
{
qwSize = MAKEQWORD(dwHi, dwLo);
}
}
catch(...)
{
bSuccess = false;
}
return bSuccess;
}
//***********************************************
DWORD CCrc32Dynamic::StringCrc32(LPCTSTR szString, DWORD &dwCrc32) const
{
_ASSERTE(szString);
DWORD dwErrorCode = NO_ERROR;
dwCrc32 = 0xFFFFFFFF;
try
{
// Is the table initialized?
if(m_pdwCrc32Table == NULL)
throw 0;
while(*szString != _T('\0'))
{
CalcCrc32((BYTE)*szString, dwCrc32);
szString++;
}
}
catch(...)
{
// An unknown exception happened, or the table isn't initialized
dwErrorCode = ERROR_CRC;
}
dwCrc32 = ~dwCrc32;
return dwErrorCode;
}
//***********************************************
DWORD CCrc32Dynamic::FileCrc32Streams(LPCTSTR szFilename, DWORD &dwCrc32) const
{
#if UNICODE || _UNICODE
return ERROR_NOT_SUPPORTED;
#else
_ASSERTE(szFilename);
_ASSERTE(lstrlen(szFilename));
DWORD dwErrorCode = NO_ERROR;
ifstream file;
dwCrc32 = 0xFFFFFFFF;
try
{
// Is the table initialized?
if(m_pdwCrc32Table == NULL)
throw 0;
// Open the file
file.open(szFilename, ios::in | ios::nocreate | ios::binary, filebuf::sh_read);
if(!file.is_open())
dwErrorCode = file.fail();
else
{
char buffer[MAX_BUFFER_SIZE];
int nLoop, nCount;
nCount = file.read(buffer, sizeof(buffer)).gcount();
while(nCount)
{
for(nLoop = 0; nLoop < nCount; nLoop++)
CalcCrc32(buffer[nLoop], dwCrc32);
nCount = file.read(buffer, sizeof(buffer)).gcount();
}
file.close();
}
}
catch(...)
{
// An unknown exception happened, or the table isn't initialized
dwErrorCode = ERROR_CRC;
}
if(file.is_open()) file.close();
dwCrc32 = ~dwCrc32;
return dwErrorCode;
#endif
}
//***********************************************
DWORD CCrc32Dynamic::FileCrc32Win32(LPCTSTR szFilename, DWORD &dwCrc32) const
{
_ASSERTE(szFilename);
_ASSERTE(lstrlen(szFilename));
DWORD dwErrorCode = NO_ERROR;
HANDLE hFile = NULL;
dwCrc32 = 0xFFFFFFFF;
try
{
// Is the table initialized?
if(m_pdwCrc32Table == NULL)
throw 0;
// 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
{
BYTE buffer[MAX_BUFFER_SIZE];
DWORD dwBytesRead, dwLoop;
BOOL bSuccess = ReadFile(hFile, buffer, sizeof(buffer), &dwBytesRead, NULL);
while(bSuccess && dwBytesRead)
{
for(dwLoop = 0; dwLoop < dwBytesRead; dwLoop++)
CalcCrc32(buffer[dwLoop], dwCrc32);
bSuccess = ReadFile(hFile, buffer, sizeof(buffer), &dwBytesRead, NULL);
}
}
}
catch(...)
{
// An unknown exception happened, or the table isn't initialized
dwErrorCode = ERROR_CRC;
}
if(hFile != NULL) CloseHandle(hFile);
dwCrc32 = ~dwCrc32;
return dwErrorCode;
}
//***********************************************
DWORD CCrc32Dynamic::FileCrc32Filemap(LPCTSTR szFilename, DWORD &dwCrc32) const
{
_ASSERTE(szFilename);
_ASSERTE(lstrlen(szFilename));
DWORD dwErrorCode = NO_ERROR;
HANDLE hFile = NULL, hFilemap = NULL;
dwCrc32 = 0xFFFFFFFF;
try
{
// Is the table initialized?
if(m_pdwCrc32Table == NULL)
throw 0;
// 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
{
QWORD qwFileSize = 0, qwFileOffset = 0;
DWORD dwByteCount, dwViewSize;
DWORD dwBaseAddress;
// Get the file size
if(!GetFileSizeQW(hFile, qwFileSize))
dwErrorCode = ERROR_BAD_LENGTH;
else if(qwFileSize != 0) // We cannot CRC zero byte files
{
// Create the file mapping
hFilemap = CreateFileMapping(hFile,
NULL,
PAGE_READONLY,
0,
0,
NULL);
if(hFilemap == NULL)
dwErrorCode = GetLastError();
else
{
LPBYTE pByte;
// Loop while we map a section of the file and CRC it
while(qwFileSize > 0)
{
if(qwFileSize < MAX_VIEW_SIZE)
dwViewSize = LODWORD(qwFileSize);
else
dwViewSize = MAX_VIEW_SIZE;
dwBaseAddress = (DWORD)MapViewOfFile(hFilemap,
FILE_MAP_READ,
HIDWORD(qwFileOffset),
LODWORD(qwFileOffset),
dwViewSize);
dwByteCount = dwViewSize;
pByte = (LPBYTE)dwBaseAddress;
while(dwByteCount-- > 0)
{
CalcCrc32(*pByte, dwCrc32);
pByte++;
}
UnmapViewOfFile((LPVOID)dwBaseAddress);
qwFileOffset += dwViewSize;
qwFileSize -= dwViewSize;
}
}
}
}
}
catch(...)
{
// An unknown exception happened, or the table isn't initialized
dwErrorCode = ERROR_CRC;
}
if(hFile != NULL) CloseHandle(hFile);
if(hFilemap != NULL) CloseHandle(hFilemap);
dwCrc32 = ~dwCrc32;
return dwErrorCode;
}
//***********************************************
DWORD CCrc32Dynamic::FileCrc32Assembly(LPCTSTR szFilename, DWORD &dwCrc32) const
{
_ASSERTE(szFilename);
_ASSERTE(lstrlen(szFilename));
DWORD dwErrorCode = NO_ERROR;
HANDLE hFile = NULL;
dwCrc32 = 0xFFFFFFFF;
try
{
// Is the table initialized?
if(m_pdwCrc32Table == NULL)
throw 0;
// 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
{
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 ebx, this // Load the CRC32 table
mov edi, [ebx]CCrc32Dynamic.m_pdwCrc32Table
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(...)
{
// An unknown exception happened, or the table isn't initialized
dwErrorCode = ERROR_CRC;
}
if(hFile != NULL) CloseHandle(hFile);
dwCrc32 = ~dwCrc32;
return dwErrorCode;
}
Submit an article or tip