Re: [ROOT] Request for iteration on TSystemDirectory

From: Valeri Fine (Faine) (fine@bnl.gov)
Date: Mon Mar 12 2001 - 18:14:00 MET


Hi, Christian 

What about:

http://root.cern.ch/root/htmldoc/TFileSet.html

One can iterate it using 

http://root.cern.ch/root/htmldoc/TDataSetIter.html

the way you described.

  Valeri


> Hi ROOT'ers, 
> 
> I'd like very much if it would be possible to iterate over a
> TSystemDirectory. I imagine one could do 
> 
> 
>   TSystemDirectory dir("some directory"); 
>   TSystemFile*     file = 0;
>   TIter next(dir);
>   
>   while ((file = (TSystemFile*)next())) {
>     // do something in this file
>     ...  
>   }
> 
> As an additional feature, one could have a constructor that uses
> wildcard globing: 
> 
>   TSystemDirectory dir("some directory", "*.root"); 
> 
> If using a TIter would not be feasable for TSystemDirectory, could one
> at least have something like:   
> 
>   UInt_t       TSystemDirectory::GetEntries(); 
>   TSystemFile* TSystemDirectory::At(UInt_t i);
> 
> so that one may iterate through the list in a sligtly more clumbersome
> way:
> 
>   Int_t n = dir.GetEntries(); 
> 
>   for (Int_t i = 0; i < n; i++) { 
>     file = dir.At(i); 
>     // do something in this file
>     ...
>   }
> 
> I realise ofcourse, that this would mean taking the internal list
> initialisation out of the Browse method, and into something else like
> say Initialise. The list can then be created "just-in-time": 
> 
>   TSystemDirectory::Browse(TBrowser* b) { 
>     // 
>     if (!fListOfDirEntries) 
>       Initialise(); 
>     ... 
>   }
>  
> and so on. I don't see why you don't have "." and ".." in the
> list. I'd imagine something like 
> 
>   TSystemDirectory::Browse(TBrowser* b) { 
>     // 
>     .
>     TString *name = GetTitle();
>     if (!name->CompareTo(".."))
>       *name = gSystem->DirName(gSystem->WorkingDirectory()); 
>     ...
>   }
> 
> would work. 
> 
> Anyway, just a few thoughts on this. I've this functionallity is in
> ROOT somewhere and I've just overlooked it, then I'm sorry for
> bothering you, and could someone please point out to me where -
> thanks. 
> 
> Yours, 
> 
> Christian  -----------------------------------------------------------
> Holm Christensen                             Phone:  (+45) 35 35 96 91 
>   Sankt Hansgade 23, 1. th.                  Office: (+45) 353  25 305 
>   DK-2200 Copenhagen N                       Web:    www.nbi.dk/~cholm    
>   Denmark                                    Email:       cholm@nbi.dk
> 



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