Bit manipulation useing "Bit Field" in C++ - C / C++ / MFC Discussion Boards

Richard Andrew x643-Jan-09 6:59

3-Jan-09 6:59

GetSubMenu() only returns a sub menu that already exists.

If you want to create a new one, you must call CreateSubMenu(), and then attach menu items to it with AppendMenu or InsertMenu.

Re: Popup Menu

korte253-Jan-09 7:46

korte25

3-Jan-09 7:46

Thaks for the answer. I created a menu (IDR_P), and I thought that loading it would do all the aforementioned, or what is the point in using creating Menu resources?
Of course if I can't get around it, i will use the method you suggested I just thought that using a resource would be simpler. Thanks again.

Re: Popup Menu

Michael Dunn3-Jan-09 18:39

Michael Dunn

3-Jan-09 18:39

Does PopupMenu.LoadMenu(...) succeed? If so, is there a popup menu at index 0 in the IDR_P menu?

--Mike--
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Re: Popup Menu

korte253-Jan-09 22:05

korte25

3-Jan-09 22:05

I also did an assertion on PopupMenu.LoadMenu() and it was OK. How can I check if there is a popup menu at index 0?
Thanks

Re: Popup Menu

korte253-Jan-09 22:25

korte25

3-Jan-09 22:25

Thanks, the latter part was the problem.

Re: Popup Menu

Stephen Hewitt3-Jan-09 21:55

Stephen Hewitt

3-Jan-09 21:55

As a side note, m_Popup is not a good name for a local variable. The m_ prefix is normally used to indicate that a variable is a member variable (member of a class or struct).

Steve

Re: Popup Menu

korte253-Jan-09 22:06

korte25

3-Jan-09 22:06

Thanks

Bit manipulation useing "Bit Field" in C++

Joseph Marzbani3-Jan-09 5:43

Joseph Marzbani

3-Jan-09 5:43

I have an array of BYTEs named aBytes. As you know, It looks some thing like this in the memory:

1000100110001010100011011011010110110101 ...
memory increase ---->

Now I want to separate 6-Bit chunks from the begin, as follow:

100010011000101010001101101101011011 ...
memory increase ---->

I used this code:

typedef unsigned __int32 BASE64
struct CHUNKS
{
        BASE64    First:6;
        BASE64    Second:6;
        BASE64    Third:6;
        BASE64    Fourth:6;
}*pChunk = NULL;

for (int iCountor = 0; iCountor < Size_Of_aBytes; iCountor++)
{
        pChunk = (CHUNKS*) (aBytes + iCountor);
        //From now on I expected to access my favorite values using <pChunk -> First>, ...
}

But each time, I get wrong values. Where is the problem? Confused | :confused:

Thank you masters!

Re: Bit manipulation useing "Bit Field" in C++

Luc Pattyn3-Jan-09 6:07

Luc Pattyn

3-Jan-09 6:07

Hi Jusef,

iCountor is counting 4-byte integers and you want the pChunk pointer to advance by 4 bytes, however aBytes is a char pointer, so adding iCountor to it is not correct. You should use one of these:
pChunk = (CHUNKS*) (aBytes + 4*iCountor);
pChunk = ((CHUNKS*)aBytes) + iCountor;

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

Love, happiness and fewer bugs for 2009!

Re: Bit manipulation useing "Bit Field" in C++

Stuart Dootson3-Jan-09 17:02

Stuart Dootson

3-Jan-09 17:02

What type is aBytes?

I'll presume it's a char or BYTE pointer. You want to increment it by sizeof (struct CHUNKS), as you want to manipulate items of that type. One wrinkle - making sure you don't increment off the end of the byte array and making sure that all of a CHUNK is in the array.

Anyway - try this:

for (int chunkCountor = 0; chunkCountor < Size_Of_aBytes/sizeof (struct CHUNKS); chunkCountor++)
{
        pChunk = ((CHUNKS*) (aBytes)) + chunkCountor;
        //From now on I expected to access my favorite values using <pchunk -=""> First>, ...
}</pchunk>

Re: Bit manipulation useing "Bit Field" in C++

krmed4-Jan-09 3:33

krmed

4-Jan-09 3:33

You're on the right track, but remember that a BYTE is 8 bits, so you can't just use aBytes + iCountor to increment the way you are.

One suggestion would be to decode three bytes (four values) at a time in your loop:

struct CHUNKS
{
	DWORD First:6;
	DWORD Second:6;
	DWORD Third:6;
	DWORD Fourth:6;
} *pChunk = NULL;

int iCountor = 0;

for (iCountor = 0; iCountor < Size_Of_aBytes; iCountor += 3)
{
	if ((iCountor + 3) <= Size_Of_aBytes)	// you have at least three bytes left, so get them all
	{
		pChunk = (CHUNKS*) (aBytes + iCountor);
		// now you can get pChunk->First, pChunk->Second, pChunk->Third, and pChunk->Fourth
		// this takes care of the first three bytes of aBytes, the next time through the loop
		// will get the next three bytes (4 values).
	}
	else
	{
			// when you get here, aBytes will only have one or two bytes of data left,
			// so you can only access one or two of the variables safely.
			
			// I'll leave this up to you.
	}
}

Note that this is UNTESTED code, but should give you what you're looking for.

Hope that helps.

Karl - WK5M
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Debug Assertion Failure

bhanu_85093-Jan-09 1:32

bhanu_8509

3-Jan-09 1:32

Hai all,

We have around 7 dialog boxes in our application. And to navigate from one dialog box to the other dialog box we use doModal(). After navigating for some time between the dialog boxes we get a debug assertion failure and when checked through call stack all the error falls into doModal() and pretranslatemessage(). Please help us out..........

Thanks and Regards
Bhanu

Re: Debug Assertion Failure

SandipG 3-Jan-09 1:39

SandipG

3-Jan-09 1:39

Please paste code snippets...

Regards,
Sandip.

Re: Debug Assertion Failure

ThatsAlok5-Jan-09 0:28

ThatsAlok

5-Jan-09 0:28

are you opening model dialog on model dialog box?

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help me...

surender992-Jan-09 21:58

surender99

2-Jan-09 21:58

i have a c library which sends and receives video from other peer, so i have to display video..i have created window for viewing video using mfc...what would be ur suggestion how to send/receive the video data from c library to my mfc application... does sendMsg can handle that huge data (around 3k-4k bytes per message)or should i go for any shared memory kindof stuff....
i have even tried of drawing my video on win32 app but it looked some what weird..... D'Oh! | :doh:

surender9

Re: help me...

Code-o-mat3-Jan-09 3:22

Code-o-mat

3-Jan-09 3:22

If i were you i'd try making it a DirectShow filter.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <

How can Create new rect with width?

Le@rner2-Jan-09 20:05

Le@rner

2-Jan-09 20:05

Hi all,

I have a Rect,

e.g:

CRect rect=CRect(10,20,20,40);

i have new width for rect like 80.

now how can i create rect with this width and other values are remains same.

please help me for this.

thanks in advance.

IN A DAY, WHEN YOU DON'T COME ACROSS ANY PROBLEMS - YOU CAN BE SURE THAT YOU ARE TRAVELLING IN A WRONG PATH

Re: How can Create new rect with width?

Hamid_RT2-Jan-09 20:27

Hamid_RT

2-Jan-09 20:27

I think you can use of CRect::DeflateRect.

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

Re: How can Create new rect with width?

Le@rner2-Jan-09 20:47

Le@rner

2-Jan-09 20:47

Hamid. wrote:
CRect::DeflateRect.

but this use for Decreases the width and height of CRect.

IN A DAY, WHEN YOU DON'T COME ACROSS ANY PROBLEMS - YOU CAN BE SURE THAT YOU ARE TRAVELLING IN A WRONG PATH

Re: How can Create new rect with width?

Hamid_RT3-Jan-09 0:16

Hamid_RT

3-Jan-09 0:16

You can decrease your width of current width with this function.

Of one Essence is the human race
thus has Creation put the base
One Limb impacted is sufficient
For all Others to feel the Mace
(Saadi )

Re: How can Create new rect with width?

CPallini2-Jan-09 20:50

CPallini

2-Jan-09 20:50

rect.InflateRect(0,0,70,0);

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

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Re: How can Create new rect with width?

Le@rner2-Jan-09 20:55

Le@rner

2-Jan-09 20:55

please explain why this.

IN A DAY, WHEN YOU DON'T COME ACROSS ANY PROBLEMS - YOU CAN BE SURE THAT YOU ARE TRAVELLING IN A WRONG PATH

Re: How can Create new rect with width?

CPallini2-Jan-09 21:04

CPallini

2-Jan-09 21:04

Your original rect (10,20,20,40) has

width = right - left = 20 - 10 = 10 pixels.

If you want it 80 pixels wide (with minimum change on coordinates) then you should move its right side 70 pixels to the right:

left<sub>new</sub>   = left;
right<sub>new</sub>  = right + 70; // now width = right<sub>new</sub> - left<sub>new</sub> = 80
top<sub>new</sub>    = top;
bottom<sub>new</sub> = bottom;

That's what InflateRect(0,0,70,0) does.
Smile | :)

Re: How can Create new rect with width?

Le@rner2-Jan-09 21:16

Le@rner

2-Jan-09 21:16

thanks ,
if new width is decrease so i can use DeflateRect or InflateRect.

IN A DAY, WHEN YOU DON'T COME ACROSS ANY PROBLEMS - YOU CAN BE SURE THAT YOU ARE TRAVELLING IN A WRONG PATH

Re: How can Create new rect with width?

CPallini3-Jan-09 2:49

CPallini

3-Jan-09 2:49

You may also use inflate with negative values.
Smile | :)

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