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Re: [gforth] Parsing a directory
From: |
Bernd Paysan |
Subject: |
Re: [gforth] Parsing a directory |
Date: |
Wed, 13 Jun 2018 01:17:15 +0200 |
Am Dienstag, 12. Juni 2018, 23:58:49 CEST schrieb Dennis Ruffer:
> I’m working on a project that needs to recursively find every file in a
> directory structure and I found some code to get started with at:
> https://www.rosettacode.org/wiki/Walk_a_directory/Recursively#Forth
>
> It is not doing what it is supposed to do and I hope to improve on it, but
> I’ve run into a stumbling block.
>
> I can’t seem to be able to open directories to see if I’ve fallen into a
> symbolic loop.
>
> For example, a symbolic link pointing to “../” will cause it to overflow
> real quickly.
>
> The only solution I can think of is to look for duplicate names, but that
> has far too many false positives.
> Here’s my code, and I’m hoping someone can suggest an alternative:
> : $append ( from len to -- ) 2DUP >R >R COUNT + SWAP MOVE R> R@ C@ + R>
> : C! ;
> :
> : dots? ( name len -- ? )
>
> \ 2dup s" ." compare 0= if 2drop true exit then
> \ s" .." compare 0= if true exit then
> drop c@ [char] . = if true exit then
> false ;
>
> : (ls-r) ( dir len -- )
>
> pad c@ >r dup >r pad count >r >r pad $append s" /" pad $append
> r> r> 2dup + 1- r> 2 + search nip nip if
> ." -> loop detected" r> pad c! exit then ( duplicate)
> pad count open-dir if drop r> pad c! exit then ( dirid)
> begin
> dup pad count + 256 rot read-dir throw
> while
> pad count + over dots? 0= if \ ignore current and parent dirs
> cr dup pad count rot + type
> pad count + swap recurse
> else drop then
> repeat
> drop r> pad c!
> close-dir throw
> ;
>
> : ls-r ( dir len -- ) 0 pad c! (ls-r) ;
>
> s" ." ls-r cr
>
> DaR
Ah yes, there's a good reason why I added unix/filestat.fs, which has lstat,
and allows you to analyze a file before you follow it.
Follow S_IFDIR files, don't follow symlinks.
--
Bernd Paysan
"If you want it done right, you have to do it yourself"
net2o id: kQusJzA;address@hidden(dQ*
http://bernd-paysan.de/
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