Hi,

Maybe it's a bit off-topic, sorry for any incovenience.

In my library I need to have a repressentation of a directorty tree in memory, to search for files etc. I'm using a tList like this :

pMyDirsItem = ^mydirsitem;
myDirsItem =RECORD
  info :tFileInfo; //name, size, time/date ...
  sub :tList;
end;
myDirs :tList;

What I do is store the file/directory name and the like in DirsItem.info and if it's a directory "sub" points to another tList with the contents of that directory. It works but I would like to know if someone have a better solution for this problem. I'm not very happy with the performance when I have to find a file in it.

thanks, Ivan

At 10/15/01 01:29 AM, you wrote:

Ivan,

A slight modification would yield a more general solution:

type
   PDirNode = ^TDirNode;
   TDirNode = record
     info : ...
     Next, Sub : PDirNode;
var
   Root : PDirNode;

For each node, you can store the file information bits, as you described. If it is a directory, the Sub will point to the node of the subdirectory, for a simple file Sub = nil. In addition, Next points to the next node (directory or file residing in the same directory), for the last node in the list, Next = nil;

To go through the whole structure (to find a file or for any other reason), you have to walk this tree--the actual order might differ but I guess post-order would be the most suited for the usual tasks you can do with file system structures. Thus, you first process the info field (eg. when looking for a file, compare the name or attributes to the one you are looking for). Then, if Sub nil, you proceed to the node pointed by Sub recursively. When you return, if Next nil, you proceed to the node pointed by it. If Next = nil, you return back to the caller. Basically:

Walk (p : PDirNode);
begin
   repeat
     ... p^.info ...
     if Sub  nil then Walk (Sub);
     p := p^.Next;
   until p = nil;
end;

Regards,

   Gabor DEAK JAHN

------------------------------------------------------------------- Gabor DEAK JAHN -- Budapest, Hungary.
WWW: www.tramontana.co.hu
E-mail:

Use a TStringList object instead of a Tlist.
Store the name in the string, and in the Object, store

TMyFileObject
  Into : TFileInfo;
  Sub : TStringList;
end;
If the stringlist object is sorted (Sorted:=True) then any search will use a binary search,
thus speeding up the search quite a lot.

Michael.

I still have some directory traversal routines. Afaik they are even in xtdfpc on my page (see contrib page). Unit is called odirtree or so.

Please send me url where i can fin CVS for windows

Thanks Zbynek

Zbynek Grygar wrote

Please send me url where i can fin CVS for windows

http://www.cvshome.org

Regards,
Adam Naumowicz

--------------------------------------
WWW: http://math.uwb.edu.pl/~adamn/
--------------------------------------

Zbynek Grygar wrote

Please send me url where i can fin CVS for windows

www.wincvs.org

Jonas

Or for wincvs... http://www.wincvs.org/ J

a binary search,

thus speeding up the search quite a lot.

fist thanks to everybody who've answered me,

And now following Michael's advice I'm using tStringList but I found that the property CaseSensitive is not declared in the class. I downloaded the FCL source some days ago so maybe it's fixed already.

bye, Ivan

There is no such property. Where did you find that ?

Michael.

In the Delphi6 help files. I looked for tStringList and in the properties section says that CaseSensitive is a boolean value that if set to true the "find" method will use CompareAnsiStr instead of CompareAnsiText. Maybe is something new in Delphi6, but I think is usefull and simple to implement.

bye, Ivan