C / C++ / MFC

27-Jul-02 7:18

I tried:

<br />
void CTrain1View::OnReadin() <br />
{<br />
	CString sWriteText; //Where the text will be streamed from<br />
	sWriteText="Rich text is shown here in sample project";<br />
<br />
	// This is hard-coded for example purposes. It is likely this would<br />
	// be read from file or another source.<br />
	EDITSTREAM es;<br />
	es.dwCookie = (DWORD)&sWriteText; // Pass a pointer to the CString to the callback function<br />
	es.pfnCallback = MEditStreamInCallback; // Specify the pointer to the callback function<br />
<br />
	m_richedit.StreamIn(SF_RTF,es); // Perform the streaming<br />
}<br />
<br />
<br />
<br />
  DWORD __stdcall MEditStreamInCallback(DWORD dwCookie, LPBYTE pbBuff, LONG cb, LONG *pcb)<br />
{<br />
	CString *psBuffer = (CString *)dwCookie;<br />
<br />
	if (cb < psBuffer->GetLength()) cb = psBuffer->GetLength();<br />
<br />
	for (int i=0;i<cb;i++)<br />
	{<br />
		*(pbBuff+i) = psBuffer->GetAt(i);<br />
	}<br />
<br />
	*pcb = cb;<br />
<br />
	*psBuffer = psBuffer->Mid(cb);<br />
<br />
	return 0;<br />
}<br />
<br />

but this did not populate the richedit control. Instead it crashed precisely at :

    for (int i=0;i<cb;i++)<br />
{<br />
    *(pbBuff+i) = psBuffer->GetAt(i);<br />
}<br />

In the debug window I could see that the entire string was retrieved, and it entered the for loop even after that. Then crashed. so is it an indexing problem? How to fix it?

Thanks,
ns

nss27-Jul-02 8:01

27-Jul-02 8:01

From the debugger, for some reason (The string is just "Rich text" with length of 9) ,I see that cb =4092, and MSDN said that the loop index is to be less than GetLength = 9. No wonder its crashing. But what is this cb thats being passed in? Helllpp!
Thank you much,
ns

Ravi Bhavnani27-Jul-02 8:02

27-Jul-02 8:02

The for loop looks bad. Did you forget to include the condition and the increment in your post? In any case, you can simply copy a CString into a char array (as it looks like what you want to do) by doing:

strcpy (pbBuff, *psBuffer->GetBuffer(0));
*psBuffer->ReleaseBuffer();

/ravi

Let's put "civil" back into "civilization"
http://www.ravib.com
ravib@ravib.com

nss27-Jul-02 8:40

27-Jul-02 8:40

Wonder why the loop got mangled in the mail

 DWORD __stdcall MEditStreamInCallback(DWORD dwCookie, LPBYTE pbBuff, LONG cb, LONG *pcb)<br />
{<br />
	CString *psBuffer = (CString *)dwCookie;<br />
	TRACE(*psBuffer);<br />
TRACE("cb is %d",cb);  //debugger says its 4092<br />
<br />
TRACE("getlength is %d",psBuffer->GetLength()); debugger says its 9, correct<br />
<br />
<br />
<br />
	//if (cb < psBuffer->GetLength()) cb = psBuffer->GetLength(); //never gets done cause cb is so big!<br />
<br />
//MSDN says loop until length-1, so I forcibly set<br />
<br />
cb =9;<br />
<br />
	TRACE("length is %d",cb);<br />
<br />
	for (int i=0;i<cb;i++)<br />
<br />
	<br />
	{<br />
<br />
			TRACE("index i is %d", i);<br />
		*(pbBuff+i) = psBuffer->GetAt(i);<br />
	}<br />
<br />
	*pcb = cb;  \\this looks weird. cb never changes....not that I can see<br />
<br />
	*psBuffer = psBuffer->Mid(cb);<br />
<br />
	return 0;<br />
}

I'm trying your idea now...
Thanks. Smile | :)

yikes! It did it again!!

nss27-Jul-02 8:42

Re: yikes! It did it again!!

27-Jul-02 8:42

The for loop is

for (int i=0;i

nss27-Jul-02 8:43

Re: yikes! It did it again!!

27-Jul-02 8:43

i=0
i less than cb
increment i

Aaargh!

Ravi Bhavnani27-Jul-02 8:45

Re: yikes! It did it again!!

27-Jul-02 8:45

That's what I thought. That's a simple strcpy, so my suggestion should work.

/ravi

Let's put "civil" back into "civilization"
http://www.ravib.com
ravib@ravib.com

Ravi Bhavnani27-Jul-02 8:44

27-Jul-02 8:44

You need to surround your code with <pre> </pre> Smile | :)

/ravi

Let's put "civil" back into "civilization"
http://www.ravib.com
ravib@ravib.com

\n in TRACE()

Ravi Bhavnani27-Jul-02 8:58

27-Jul-02 8:58

Don't forget to include "\n" at the end of your TRACE() string, otherwise you may need to cross the Atlantic to view the debugger output. Highly inconvenient.

/ravi

Let's put "civil" back into "civilization"
http://www.ravib.com
ravib@ravib.com

Bill S27-Jul-02 8:47

Bill S

27-Jul-02 8:47

Try this:

DWORD CALLBACK _LoadRtfCallback(
DWORD dwCookie, // (in) pointer to the string
LPBYTE pbBuff, // (in) pointer to the destination buffer
LONG cb, // (in) size in bytes of the destination buffer
LONG FAR *pcb // (out) number of bytes transfered
)
{
LPCTSTR pszMsg = (LPCTSTR)dwCookie;

// number of bytes to copy
*pcb = _tcslen( pszMsg ) * sizeof(TCHAR);

// limiting it up to the buffer's size
if( *pcb > cb )
*pcb = cb;

// copying the string to the buffer
memcpy( pbBuff, pszMsg, *pcb );

// advancing to the end of the string
pszMsg += *pcb / sizeof(TCHAR);

// if it's the end of the string, returns NULL;
// otherwise, returns a pointer to the next char to transfer as the cookie
return ( *pszMsg != '\0' ) ? (DWORD)pszMsg : NULL;
}

nss28-Jul-02 6:54

28-Jul-02 6:54

I am wondering - in CRichEditStream::_LoadRtfCallback, is CRichEditStream replaced by the name of my view class? Why does this callback have a different signature type from what I see in the MSDN:

DWORD __stdcall MEditStreamOutCallback(DWORD dwCookie, LPBYTE pbBuff, LONG cb, LONG *pcb)

You have

DWORD CALLBACK _LoadRtfCallback(
DWORD dwCookie, // (in) pointer to the string
LPBYTE pbBuff, // (in) pointer to the destination buffer
LONG cb, // (in) size in bytes of the destination buffer
LONG FAR *pcb // (out) number of bytes transfered
)

Are these two forms of the function declaration equivalent? Can I use your function in conjunction with:

void CRichEgView::OnReadin() 
{
	CString sWriteText; //Where the text will be streamed from
	sWriteText="Rich text is shown here in sample project";

	// This is hard-coded for example purposes. It is likely this would
	// be read from file or another source.
	EDITSTREAM es;
	es.dwCookie = (DWORD)&sWriteText; // Pass a pointer to the CString to the callback function
	es.pfnCallback = MEditStreamInCallback; // Specify the pointer to the callback function

	GetRichEditCtrl().StreamIn(SF_RTF,es); // Perform the streaming
}

What will this line be when used with your function:

es.pfnCallback = MEditStreamInCallback; // Specify the pointer to the callback function

Sorry if my questions sound naive Smile | :)

Thanks,
ns

trying out your idea

nss28-Jul-02 7:34

28-Jul-02 7:34

Here is how I used it, -it ran but the box remained stubbornly blank!

void CTrain1View::OnReadin() 
{
	CString sWriteText; //Where the text will be streamed from
	sWriteText="Rich text is shown here in sample project";

	// This is hard-coded for example purposes. It is likely this would
	// be read from file or another source.
	EDITSTREAM es;
	es.dwCookie = (DWORD)&sWriteText; // Pass a pointer to the CString to the callback function
	es.pfnCallback = _LoadRtfCallback; // Specify the pointer to the callback function

	m_richedit.StreamIn(SF_RTF,es); // Perform the streaming
}

DWORD CALLBACK _LoadRtfCallback(
   DWORD dwCookie,      // (in) pointer to the string
   LPBYTE pbBuff,       // (in) pointer to the destination buffer
   LONG cb,             // (in) size in bytes of the destination buffer
   LONG FAR *pcb        // (out) number of bytes transfered
   )
{
   LPCTSTR pszMsg = (LPCTSTR)dwCookie;

   // number of bytes to copy
   *pcb = _tcslen( pszMsg ) * sizeof(TCHAR);

   // limiting it up to the buffer's size
   if( *pcb > cb )
      *pcb = cb;

   // copying the string to the buffer
   memcpy( pbBuff, pszMsg, *pcb );

   // advancing to the end of the string
   pszMsg += *pcb / sizeof(TCHAR);

   // if it's the end of the string, returns NULL;
   // otherwise, returns a pointer to the next char to transfer as the cookie
   return ( *pszMsg != '\0' ) ? (DWORD)pszMsg : NULL;
}