Re: [Unicon-group] Walk of file directory

Sat, 10 Jan 2015 22:17:18 -0800

Jafar,
 
Thank you for a whole bundle of advices and suggestions! Threads are worth to try. The thought of search by file attributes is very useful too. Your suggestion about slow I/O partly is right. For UNIX I tried the program on Raspberry Pi with 6 Class microSD as HDD (it's slow, agree). But for Windows it was quite fast HDD. It would be interesting to compare performance of the program on Windows with classic approach based on Win32 _FINDFIRST, _FINDNEXT functions. I have threaded Delphi/Lazarus implementations of this algorithm. Feel that it will be faster but in which degree?
 
Sergey
 
10.01.2015, 21:50, "Jafar Al-Gharaibeh" <[email protected]>:
Sergey,
 
  There are so many things that came to mind when I saw your program.
 
1-  At the end of your email, sourceforge ad says "Go Parallel", Which is not a bad idea for this highly parallel application. 
 
 There is a similar program "wordcount" listed in my dissertation (available on unicon.org) that go through directories and count words in every file using threads (Chapter 7, page 107)
 
2- Unicon open() already supports " pattern matching that would greatly (I believe) speedup your program. For example you can do this:
    L := open("*.icn")
 
   to get a list of all of Unicon source files in the current directory. 
 
  Note: It would be nice if there were a way to tell open() to return files not only based on a pattern, but also on file attribute to allow something like "get me all directories in the current directory", or "get me all read only file". There are a lot of situations where filtering directory names for example is very useful - like this program
 
3- The program on Rosetta Code is not optimized for speed. You can minimize the number of lists created and put() by careful rewriting of the code.
 
4- Depending on how deep the directory tree is, there might be a lot of I/O going on. A slow disk might limit how fast you can go regardless of how optimized your code is.
 
I will share results if get around trying any of these options.
 
Cheers,
Jafar
 
 

On Sat, Jan 10, 2015 at 5:51 AM, Sergey Logichev <[email protected]> wrote:
Hello all!
 
Now I investigate the best approach to get list of files in specified directory and beneath in Unicon.
 
I reconstructed this one to implement matching of filenames to specified pattern (regular _expression_). My program recursively walks a directory and prints appropriate filenames. The same as dir (ls) does. All working fine except performance. If directory has a lot of subdirs the search may took 10-20 seconds before starting output. Could you provide some advices how to enchance the performance?
 
Some notes how to make and use. Unpack content of udir.zip to your local directory. Define which environment you use in env.icn file - uncomment line "$define _UNIX 1" in the case of UNIX. Nothing to do in the case of Windows.
Make udir program:
unicon -c futils.icn
unicon -c options.icn
unicon -c regexp.icn
unicon udir.icn
 
Usage: udir -f<filemask>
for example: udir -f*.icn
shall list of icn files in the current dir and all its subdirectories.
 
Best regards,
Sergey Logichev

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