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Objects will be accessed and removed pretty much at random.
This is a big point here. Straight lists perform very poorly on lookup. The list has to be searched sequentially to find the object.
However, for lists, insertions are very fast. So are removals. But when you compare them to maps, lists insert and removals probably are much faster at all.
IMHO, I see little reason to even bother with a list. Just given that you are doing random lookups, you really need something that is fast.
If available in your STL (i.e. STLPort), you might take a look at a hash map. Since your data set is remaining a constant size, you don't have to worry about the re-hash performance hit. As long as your ID's are well distributed, hash maps should perform very fast.
... IMHO 
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>>Since your data set is remaining a constant size, you don't
>>have to worry about the re-hash performance hit.
Is this true, even thought the ID's I'll be hashing on are constantly increasing?
Thinking about it, a list is definately not the way to go. As you rightly say, the lookup times for a random element in a list would /not/ be great, and that's my main priority.
I'm using M$'s STL. I'm not sure about a hash map. Is this similar to a map<obj_id, pObjData>? Forgive my ignorance, I haven't used the STL much.
Thanks,
Pete
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It is hash_map <x,y>. You probably don't have it but no big deal. Map should work just fine.
If you did have have_map, ever increasing IDs wouldn't be a problem since the ID (used as the hash value) would be moduloed by a prime number. Thus as far as the hash is concerned, the values just roll over back to 0. But even that isn't something you have to worry about unless (ID % nHashPrime) is poorly distributed. (Which is probably isn't.)
(FYI: That was my response. Was having cookie problems.)
Tim Smith
I know what you're thinking punk, you're thinking did he spell check this document? Well, to tell you the truth I kinda forgot myself in all this excitement. But being this here's CodeProject, the most powerful forums in the world and would blow your head clean off, you've got to ask yourself one question, Do I feel lucky? Well do ya punk?
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Ok, well I guess I'll use map, but thanks for the info
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Anonymous wrote:
If available in your STL (i.e. STLPort), you might take a look at a hash map.
hash_map is also available in VS.NET. Also, since you are not storing key and values you may consider a set or a hash_set.
Best regards,
Alexandru Savescu
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stl::map will work for you.
example for map with GUID* (128 bit) key type and BSTR value:
implement GUIDless to compare GUID's
struct GUIDless : public std::less<GUID*>
{
bool operator()(const GUID* _X, const GUID* _Y) const
{
if(((__int64*)_X)[0] < ((__int64*)_Y)[0])
return true;
if(((__int64*)_X)[0] == ((__int64*)_Y)[0])
{
if(((__int64*)_X)[1] < ((__int64*)_Y)[1])
return true;
else
return false;
}
return false;
}
};
declaration of map with( GUID*, BSTR) pair
std::map< GUID* ,BSTR ,GUIDless > mapGUID_BSTR;
soptest
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or do i need to do some assembly programmin gto achieve that?
Thanks
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Read on http://codeguru.earthweb.com/system/ReadSector.html
Papa
Murex Co
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Hi,
do you know some MFC or Win32 function that could help to determine whether the given file is text or binary?
Thanks
R.
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A text file and a binary file are the same... what exactly do you mean by binary and text?
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i have to find some info (words, sentences) in files on the local disk which is meaningless eg for pictures, and executables.
That why I wanna to check beforhand whether it is meaningful to search for my data.
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hmm, you could search for null, i don't think there's null in normal text files.
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yeh, but that is not a life insurance.
However your answer implies that there is no such function. That means I have to find another solution like extension checking
Thanx
R.
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there IS no way of telling if a given file is so called 'text' or so called 'binary', therefor you have to guess it.
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You could open in binary mode and read a block, then test for certain characteristics. ASCII doesn't use any bytes larger than 127, and lines are terminated with CRLF. Finding a block of perhaps 1 KB that contains no bytes >127 would be a strong indication that the file is probably text.
Let's Put The Fun Back In Dysfunctional! - My Darts Team T-shirt
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I think you're on your own.
Suggestions:
1) Open the file and read first 1-2K and check for ASCII < 20 and ASCII > 127. (By far the simplest.)
2) Open the file and read first 1-2K and look for SPACES and puntuation (,.!?'";). I would expect the length of words on average to be pretty small (<20 letters).
3) Open the file, check first 1-2K for words in a dictionary. If most words found are not in the dictionary, it's probably binary.
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10x for the excellent ideas
R.
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Open the file. Read the first 1024 bytes. You can bet yourself that if it's a binary file there will be a few bytes within the first 1024 that are not alphanumeric or punctuation.
Nish
p.s. If you have UNICODE text files you have a problem though
Author of the romantic comedy
Summer Love and Some more Cricket [New Win]
Buy it, read it and admire me
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We are facing a problem of :
We call a VC++ exe (Form View single document application) from C#
But we want to close it after it’s execute
We tried after
WaitForProcess
Process.CloseMainWindow
&
Process.Close
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The following C++ code waits for the app to terminate before continuing. It may be of some help
HANDLE hProcess = NULL;
SHELLEXECUTEINFO shellInfo;
::ZeroMemory(&shellInfo, sizeof(shellInfo));
shellInfo.cbSize = sizeof(shellInfo);
shellInfo.fMask = SEE_MASK_NOCLOSEPROCESS;
shellInfo.nShow = SW_HIDE;
shellInfo.lpFile = _T("anyapp.exe");
shellInfo.lpParameters = args;
if(::ShellExecuteEx(&shellInfo))
{
hProcess = shellInfo.hProcess;
if (hProcess != NULL)
{
::WaitForSingleObject(hProcess, INFINITE);
::CloseHandle(hProcess);
}
}
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I am displaying a modeless dialog in my app...everything related to the dialog works fine. However, there is a button in the Windows taskbar with no text displayed and it is associated with the modeless dialog.
How do I get the button not to appear in the taskbar when the modeless dialog is launched?
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There is an article here on CP that Chris Maunder wrote.
And Mike Dunn: This question should be in the FAQ!
Rickard Andersson@Suza Computing
C# and C++ programmer from SWEDEN!
UIN: 50302279
E-Mail: nikado@pc.nu
Speciality: I love C# and C++!
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Read :-
http://www.codeproject.com/useritems/dlgboxtricks.asp
There is a tip there called "Removing the task bar icon of your dialog based App"
Use the same technique mentioned there.
Nish
Author of the romantic comedy
Summer Love and Some more Cricket [New Win]
Buy it, read it and admire me
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Thanks for the reply. I found an easier way (in a reply to an article)...just set the dialog style to Tool Window. Now I have another problem to work through...I want the modeless dialog window to always be on top, so I made it the topmost window...works fine. I want to keep it from grabbing the focus every time I move or resize the MDI Mainframe window... the mainframe window is the dialog's parent.
Any Ideas?
Also, the dialog remains on top when I switch to other applications like Word or Excel...Does anyone now how to stop this behavior?
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