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List:       kde-devel
Subject:    Re: [despammed] Best way to recursive folders?
From:       Esben Mose Hansen <esben () despammed ! com>
Date:       2003-05-03 7:38:06
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On Saturday 03 May 2003 02:41, Mosfet wrote:
> Okay, I got a C function that creates or removes thumbnails recursively.
> Since it has a lot of local variables like the dir structures and such it
> can get pretty expensive if you have many depths of recursion.
>
> For this reason I'm thinking of doing a smaller recursive loop that just
> adds folders to process to a single linked list. Then when doing the actual
> processing I'd go through the list iteratively. This would be less memory
> intensive but would require more file processing since your scanning dirs
> twice: once recursively to load up the list to processes and then when your
> processing the resulting list iteratively.
>
> Any suggestions on the best way to handle recursive directory processing?

You can combine the above approaches: When scanning the first directory,  push 
any directories to a stack. When done with this directory, take the top 
directory and process that in the same way. As this is tail recursion, it can 
be replaced with a simple look. In psedo code, in pseodu C++:

stack<Directories> dirs_to_be_processed;
do {
	for each file in diretory{
		if (file is a directory) 
			dirs_to_be_processed.push(file);
		processFile(file);
	}
} while (!.stack.empty())

This kind of approach often works like a charm when you want to rid yourself 
of those nasty recursions :-)

-- 
regards, Esben

esben@despammed.com *---* http://home.worldonline.dk/~mesben


 
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