C / C++ / MFC

csrss wrote:

VirtualAlloc(0,
BASE_BUFFER_SIZE, MEM_RESERVE, PAGE_READWRITE);

BYTE *ReadBytes(HANDLE hDevice, LPDWORD lpdwBytesRead)
{
	SIZE_T BASE_BUFFER_SIZE = 512;

	BYTE * bInitialBuffer = NULL;
	bInitialBuffer = (BYTE *)VirtualAlloc(0, 
			BASE_BUFFER_SIZE, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);

	if(bInitialBuffer == NULL)
	{
		// handle this sh*t
		TRACE("VirtualAlloc failed!");
		return NULL;
	}
	DWORD dwReadBytes;
	while (FALSE != ReadFile(hDevice, bInitialBuffer, BASE_BUFFER_SIZE, 
		(LPDWORD)&dwReadBytes, 0) && dwReadBytes > 0)
	{
		TRACE1("got some buffer! %d", dwReadBytes);
		lpdwBytesRead += dwReadBytes;
	}
	return bInitialBuffer;
}

DWORD read = 0;
BYTE *DataBuffer = ReadBytes(hFile, &read);

while (FALSE != ReadFile(hDevice, bInitialBuffer, BASE_BUFFER_SIZE, 
		(LPDWORD)&dwReadBytes, 0) && dwReadBytes > 0)
	{
		TRACE1("got some buffer! %d", dwReadBytes);

lpdwBytesRead += dwReadBytes;

DWORD read = 0;
BYTE *DataBuffer = ReadBytes(hFile, &read);

#define BASE_BUFFER_SIZE 512

BOOL ReadBytes(HANDLE hFile, PBYTE bInitialBuffer)
{
	DWORD dwReadBytes;
	while (FALSE != ReadFile(hFile, bInitialBuffer, BASE_BUFFER_SIZE, 
		(LPDWORD)&dwReadBytes, 0) && dwReadBytes > 0)
	{
		/*CString str;
		str.Format(L"got buffer! %d",dwReadBytes);
		AfxMessageBox(str);*/
     }
     if(dwReadBytes <= 0) 
	 { 
		 return FALSE;
	 }
	 return TRUE;
}

void CMTest1Dlg::OnBnClickedOk()
{
	HANDLE hFile = NULL;

	hFile = CreateFile(L"C:\\temp\\myfile.txt", GENERIC_READ, 0, 0, OPEN_EXISTING, 0, 0);
	if(INVALID_HANDLE_VALUE == hFile){
		AfxMessageBox(L"CreateFile failed");
		return;
	}

	BYTE *buffer = NULL;
	buffer = (BYTE *)VirtualAlloc(0, BASE_BUFFER_SIZE, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
 
	if(NULL == buffer)
	{
		AfxMessageBox(L"VirtualAlloc failed!");
		return;
	}
	BOOL bRead = ReadBytes(hFile, buffer);
	//use buffer here
}

csrss wrote:

i cannot return bytes from function, (this code is a function, which should read a file into BYTE array and return this array among with nr of bytes read).

*lpdwBytesRead += dwReadBytes;

csrss wrote:

lpdwBytesRead += dwReadBytes;

va_list  args;
va_start(args, s_Format);
char s_Out[1024];
sprintf(s_Out, s_Format, va_arg(args, char*));

barneyman wrote:

you can't use ShellExecute like that