|
I can assume CRT functions would probably out perform my own for loop functions...?
The idea is this:
I have a buffer[0xFFFF] I wish to iterate the buffer looking for sequences of characters (carriage returns).
Currently I have something like:
for(int i=0; i<MAX_BUFF_SIZE && m_nLines < iLine; i++)
{ if(buffer[i] == 13) m_nLines++; }
It occurred to me that this can also be accomplished using CRT functions, which I thought are probably tweaked as tweaked can get...so I should probably use that implementation instead of the above...???
If you know if the CRT would out perform lemme know and if you wanna profile for me or check out the assembly dump and compare instructions, by all means please do so... 
Save me alot of time...or if your just damn sure that CRT would be faster...lemme know...
Thanx a million
Cheers! 
"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr
|
|
|
|
|
I doubt strchr will help much. In fact, it might hurt if you make the following optimization to your routine.
if (m_nLines < iLine)
{
for (int i = 0; i < MAX_BUFF_SIZE; i++)
{
if (buffer [i] == 13)
{
m_nLines++;
if (m_nLines >= iLine)
break;
}
}
}
Now, you might get some improvement with using memchr.
Tim Smith
I'm going to patent thought. I have yet to see any prior art.
|
|
|
|
|
Look under \Program Files\Microsoft Visual Studio\VC98\CRT\SRC\Intel\ for the file STRCHR.ASM
It's fast as hell.
lazy isn't my middle name.. its my first.. people just keep calling me Mel cause that's what they put on my drivers license. - Mel Feik
|
|
|
|
|
Where will you be using this loop? If it gets called only once in a while, I would not worry about tweaking its performance because it is relatively simple loop that counts the number or return carraiges in a buffer.
However if you are going to be calling this function every time that a character is pressed that is another issue.
Build a man a fire, and he will be warm for a day
Light a man on fire, and he will be warm for the rest of his life!
|
|
|
|
|
(for previous message, threading error)
*SLAP* (myself)
When I said it wouldn't help much, I had just seen the C version of the routine. Silly silly me.
But I still think memchr would be a better fit for him.
Tim Smith
I'm going to patent thought. I have yet to see any prior art.
|
|
|
|
|
Paul Watt wrote:
However if you are going to be calling this function every time that a character is pressed that is another issue.
Yes this correct...I chose this over a line vector(terminology???) so it gets called each time a key is pressed...
"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr
|
|
|
|
|
How is memchr() better than strchr()? Are there fewer instructions...? Faster instructions....? Whats the deal...?
"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr
|
|
|
|
|
strchr assumes NULL terminated string. Thus an extra test for a NULL. memchr doesn't have that.
Tim Smith
I'm going to patent thought. I have yet to see any prior art.
|
|
|
|
|
Awesome...thanks
I suppose I could have up the *.asm files myself and determined which was faster, but I guess I just wasn't thinking. 
Thanx again!
"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr
|
|
|
|
|
This is what I was thinking, I just needed to hear it form somebody other than myself...
Thanx
p.s - No i don't hear voices
"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr
|
|
|
|
|
Hi,
I'm very new to VC++ and I hope someone can help me out!
I'm trying to write a program to take audio samples from the sound card but I keep getting an "unresolved external symbol" error and I have no idea why! I have the code to set up the wave format but once I try and query the soundcard it complains. Am I doing something wrong?
Record Sound error LNK2019: unresolved external symbol__imp__waveInOpen@24 referenced in function "void__cdecl RecordWaveFile(void)" (?RecordWaveFile@@YAXXZ)
void RecordWaveFile()
{
HWAVEIN WaveHandle;
WAVEFORMATEX WaveFormat;
WaveFormat.wFormatTag = WAVE_FORMAT_PCM;
WaveFormat.nChannels = 1;
WaveFormat.nSamplesPerSec = 22050;
WaveFormat.wBitsPerSample = 8;
WaveFormat.nAvgBytesPerSec = 22050;
WaveFormat.nBlockAlign = 1;
WaveFormat.cbSize = 0;
int Res = waveInOpen(&WaveHandle, WAVE_MAPPER, &WaveFormat, 0, 0, WAVE_FORMAT_QUERY);
if (Res == WAVERR_BADFORMAT) return;
}
Thanks in advance,
Paddy.
|
|
|
|
|
Add to your project settings, under 'Link->Object/Library modules' tab, Winmm.lib.
That's bout-it. 
--BlackSmith--
/*The roof is on fire, we don't need no water, let the MF burn*/. BHG.
|
|
|
|
|
Thanks,
You wouldn't believe how long I've been trying to fix that for!!!
|
|
|
|
|
Alternatively, you can also put #pragma comment(linker, "winmm.lib") to the top of the source file. That's the way I do it whenever I need to link with a new lib file apart from the ones already set in the linker options
regards
modified 12-Sep-18 21:01pm.
|
|
|
|
|
|
When i try to open a video decompressor used for drawing, it causes a user breakpoint. If i just try to open it for decompressing, it works fine! Here's how i do it:
hVideo = ICLocate(ICTYPE_VIDEO, VideoHeader.fccHandler, &VideoInfo.bmiHeader, NULL, ICMODE_DRAW);
If i do exactly the same except chane ICMODE_DRAW to ICMODE_DECOMPRESS everything works fine. What am i doing wrong?
Tanks all!
-Rune Svendsen
|
|
|
|
|
I recently switched from VS6 to VS.Net for writing unmanaged C++. I noticed they took away the Wizard to derive a class from a CRecordset and wrap it around a table. I only know how to access database using CDatabase and CRecordset (or a class derived from them). I am guessing that the idea is to get away from ODBC and to start using OLE or ADO. I found an article in a book describing a set of classes CADOConnection and CADORecordset. I cannot find neither of them mentioned on MSDN, so my first questions is does anyone heard of and used these classes and if so is there any documention on them. My Next question is what alternatives does anyone else like to use instead of CRecordset? I know that OLE is faster than ADO, but is that much faster and is ADO that much easier to use? One last question, for anyway using generic CRecordsets, what is the easiest way to tell if a field is null, I know i can do it from a class that is derived and has teh DDX calls, but what about just a CRecordset?
JD
|
|
|
|
|
Hi,
I personaly use ADO objects.
Have a look at the article "ADO at a glance" for an introduction to ADO.
Pyt
|
|
|
|
|
What unmanaged VC++ ADO objects are there, and what is there header file?
JD
|
|
|
|
|
I have done my fair share of DB programming during the last years and all I have to say is...
Stay away from ADO, it contains so many gotchas that it's plain silly. Also it really lacks the performance needed for heavy multi-user system.
My recomendation would be OLEDB by using the ATL supportclasses (CCommand, CRowset and so on). Use the wizard to get the hang of things then write your own code by hand since the wizard (IMHO) is a bit to stupid to be used in production code.
If you still REALLY want to use ADO get the MS Press book, Programming ADO (it's good), and read it cover-cover atleast 2 times then check out OLEDB again
|
|
|
|
|
How can I set these attributes to a CFont obj? How can I create a font which is bold/italic using CFontDialog?
10x. Bless you.
--BlackSmith--
/*The roof is on fire, we don't need no water, let the MF burn*/. BHG.
|
|
|
|
|
Implement a LOGFONT object to hold the attribute of the font.
Kuphryn
|
|
|
|
|
hi,
i have an mdi-program.
i would like to hide something in mainframe (e.g. 'File'), after a password input should it then be usable.
thanks,
Lucky
|
|
|
|
|
Make an OnUpdateCommandUI handler for it and enable only when your conditions are met.
I do not know if this works for the 'predefined' Menus too. Maybe your handler gets no chance to handle because it is after the 'builtin' one.
|
|
|
|
|
I want to create tabbed toolbar, i.e tabs present on toolbar and we can easily switch from one property page to another within same toolbar. Is there anything present here at CP?? Or please give me idea ??
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
