C / C++ / MFC

13-Dec-11 20:20

hi all,

i want to test comressed file or Archive in my MFC application.

i want its a valid zip file or not.

i have no idea from where i have to start.

please guide me and help me for this.

thanks in advance.

Richard MacCutchan13-Dec-11 22:09

13-Dec-11 22:09

Use Google to find details on the different types of compressed files and their signatures.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Le@rner13-Dec-11 23:52

13-Dec-11 23:52

now how to open these files and decide these are valid archive or not.

Richard MacCutchan14-Dec-11 0:08

14-Dec-11 0:08

I just explained what you need to do; what more information do you need?

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Le@rner14-Dec-11 0:35

14-Dec-11 0:35

on signature basis i just found file is which type not that is valid or not.

so i want any class or function using the i can find the file is valid or not.

like test method in 7zip application.

Richard MacCutchan14-Dec-11 0:38

14-Dec-11 0:38

Given the problem you are trying to resolve I would think you will have to write the function yourself. There are lots of resources on the internet concerned with compressed files that will help you.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Le@rner14-Dec-11 0:46

14-Dec-11 0:46

can provide any one out of this

thanks.

David Crow14-Dec-11 3:34

David Crow

14-Dec-11 3:34

Le@rner wrote:
i want its a valid zip file or not.

Are you using some sort of ZIP library or API?

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Le@rner14-Dec-11 17:16

14-Dec-11 17:16

use the LiteZip and LiteUnZip article from code project.

LiteZip and LiteUnzip[^]

i am use its dll in my application.

Messure function execution time

David Crow15-Dec-11 2:07

David Crow

15-Dec-11 2:07

So why not post your question to that article so the author will see it? Surely he has written some sort of "zip test" functionality to that library.

columbos1492713-Dec-11 1:40

columbos14927

13-Dec-11 1:40

Hello,
i googled a lot and and dont know what is the best way to messure the time that takes an execution of a function,is there some "stopwatch" in MFC?

Thanks

enhzflep13-Dec-11 1:48

enhzflep

13-Dec-11 1:48

Just use QueryPerformanceCounterFrequency and QueryPerformanceCounter.

See here[^]

columbos1492713-Dec-11 2:09

columbos14927

13-Dec-11 2:09

Hey,
Just to make sure i understood right

I query the count at the begining and at the end, then i devide it by the frequency and the result is the soconds?

Thanks

Stefan_Lang13-Dec-11 2:29

Stefan_Lang

13-Dec-11 2:29

A thing to note: 'to measure' is the act of determining the value of a property. 'to mess (something up)' is somewhat synonym to 'meddle' or 'create chaos'. I'll assume that by 'messure' you mean the former, not the latter. Wink | ;)

Problem with owner drawn listbox and double buffering

Code-o-mat13-Dec-11 5:12

Code-o-mat

13-Dec-11 5:12

To 'meddle' with the 'value of a property': messure Smile | :)

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> If it doesn't matter, it's antimatter.<

aangerma13-Dec-11 1:26

aangerma

13-Dec-11 1:26

Hello,

I created owner drawn listbox and I used double buffering
for preventing flickering because I have a lot of data ,
the problem is that its don't present all the items and ,
whan I scroll it down and up its erases part of the items,
the code is:

C++

void HistDlg::OnDrawItem(int nIDCtl, LPDRAWITEMSTRUCT lpDrawItemStruct)
{
	if(IDC_LIST1 ==nIDCtl)
	{
		int width=lpDrawItemStruct->rcItem.right-lpDrawItemStruct->rcItem.left;
		int height=lpDrawItemStruct->rcItem.bottom-lpDrawItemStruct->rcItem.top;
		HDC memDC1 = CreateCompatibleDC(lpDrawItemStruct->hDC);
		HBITMAP hMemBmp = CreateCompatibleBitmap(lpDrawItemStruct->hDC,width , height);
		HBITMAP hOldBmp = (HBITMAP)SelectObject(memDC1, hMemBmp);
		CDC *memDC=CDC::FromHandle(memDC1);
		memDC->FillSolidRect(0,0, width, height,RGB(255,255,255));

		int	 ODI_length =  
		1 + SendDlgItemMessage(IDC_LIST1,
								   LB_GETTEXTLEN,
								   lpDrawItemStruct->itemID,
								   0);

		if (ODI_length)
		{
			wchar_t *ODI_wstr = NULL;
			ODI_wstr = new wchar_t[ODI_length];
			if (ODI_wstr)
			{
				COLORREF ODI_old_text_color;
				//get the string
				SendDlgItemMessage(IDC_LIST1,
								   LB_GETTEXT,
								   lpDrawItemStruct->itemID,
								   (LPARAM)ODI_wstr);
					
					
				memDC->DrawText(ODI_wstr,
							  ODI_length - 1,
							  &lpDrawItemStruct->rcItem,
							  DT_RIGHT);
				
			}

		}
	
		BitBlt(lpDrawItemStruct->hDC, 0, 0, width,height, memDC1, 0, 0, SRCCOPY);
		SelectObject(memDC1, hOldBmp);
		DeleteObject(hMemBmp);
		DeleteDC(memDC1);
	}
}

What doe's I'm doing wrong?

thanks

Re: Problem with owner drawn listbox and double buffering

CPallini13-Dec-11 1:49

CPallini

13-Dec-11 1:49

aangerma wrote:
BitBlt(lpDrawItemStruct->hDC, 0, 0, width,height, memDC1, 0, 0, SRCCOPY);

Shouldn't this be:

C++

LONG left = lpDrawItemStruct->rcItem.left;
LONG top = lpDrawItemStruct->rcItem.top;
BitBlt(lpDrawItemStruct->hDC, left, top, width,height, memDC1, 0, 0, SRCCOPY);

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[My articles]

Thread Sync

columbos1492712-Dec-11 22:22

columbos14927

12-Dec-11 22:22

Hello,
I am writing an application that perform image acquisition frome a camera.

The image aqcuisition is done by a DLL Supplied by the camera manufactorer.

Basicaly im initializing the DLL and then i start capture,in my application i defened a function that is called by the DLL every captured frame,this "OnFrameCapturedHandler" function gets the frame as the parameter.
Then i perform some calculation on the frame and i display it on the GUI.

But the problem is that the grabbing is faster then my calculation so what happens is that a new frame comes in while the previous is still processed.So what i need is some way to block or to make "OnFrameCapturedHandler" not to do anything while previos frame is Processed.
I tried to put boolean at the begining of "OnFrameCapturedHandler" and set it to false while still processing and at the end set it to true.
And before entering the "OnFrameCapturedHandler" check it.but it freezes my app.

???
Thnaks.

Richard MacCutchan12-Dec-11 22:55

12-Dec-11 22:55

I think the comments from Pete O'Hanlon in this thread[^] explain what is wrong and what you need to do.

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

Albert Holguin13-Dec-11 3:19

Albert Holguin

13-Dec-11 3:19

You have to use some sort of thread synchronization object. Simply using a boolean does not work!

There's a few options:
0. Event (see CreateEvent()) coupled with a WaitForSingleObject().
1. Mutex (or Critical Section)
2. Semaphore

There's actually a few articles on the subject here on CP (and the internet in general):
Thread Synchronization for Beginners[^]
Synchronized multi-threading in C++ (No MFC!)[^]
http://www.informit.com/library/content.aspx?b=Visual_C_PlusPlus&seqNum=149[^]

Chuck O'Toole13-Dec-11 4:02

Chuck O'Toole

13-Dec-11 4:02

I just want to point out that if, as you say "the problem is that the grabbing is faster then my calculation", then you are destined to lose frames. Threads and frame queues may help with the management of the arriving data but it is basic queueing, if your per-frame processing time exceeds the frame inter-arrival time, you will have problems. This basic tenet was masterfully demonstrated by the late Lucile Ball in the famous "chocolate candy factory" skit. Processing/interarrival mismatch[^]

Once you get the synchronization of the threads and queueing out of the way, you either need to make your processing faster or decide on how you choose which incoming frames to discard.

modified 13-Dec-11 10:46am.