Re: [MacPerl] Folder recursion and recognition problem

[ajf@afco.demon.co.uk (Alan Fry)]

>>At 1:02 PM -0500 03/06/96, Hal Wine wrote:
>>>This means you should either:
>>>a) do a chdir() to the supplied directory, then always do an opendir()
>>>on the current directory (':' for Mac, '.' for unix/dos).  Or,
>>>b) always prepend the directory to the filename returned by readdir().
>>>
>>>My hunch is (a) runs faster on the Mac (due to internals of the Mac
>>>file system), and no slower on other file systems.
>>
>>No, according to Matthias, a) shouldn't run faster. He said MacPerl fully
>>expands relative pathnames to absolute pathnames before doing anything with
>>them.

and on June 4:

>Well, I hate to disagree with Matthias, but (a) DOES run faster, and
>works correctly, while (b) has bugs. (See attached script)  Here's the
>timing for 10,000 stats of a directory where the path string is 223
>characters, and 7 levels deep (excluding volume name):
>    Perl 5.0.7r1m:
>      194 seconds for full path stat
>      120 seconds for relative stat
>    MacPerl 4.1.8:
>      200 seconds for full path stat
>      126 seconds for relative stat
>
>So, we see that using a full path is about 60% slower than relative
>directories.

I agree with Hal. I have attached two little scripts which can be used for
timing. <Speed 2> takes between 58% and 62% of the time taken by <Speed 1>

Alan

=============================================================================

#!perl
#Speed 1
$begin = times;
open (OUT, ">List 1");

$start = (shift @ARGV);
lstat($start);
print OUT "$start:\n";

&DoIt($start);

sub DoIt {
    local($it) = @_;
    local(@files);
    if (-d _) {
        opendir(DIR, $it);
        @files = readdir(DIR);
        closedir(DIR);
        foreach ( @files ) {
            lstat("$it:$_");
            unless (-d _) {
                "$it:$_" =~ /$start:(.*)/;
                $str = $1;
                print OUT ("$str\n");
                next;
            }
            &DoIt("$it:$_");
        }
    }
}
$finish = times;
print OUT "\n",'Time taken = ',$finish - $begin,"\n";

=============================================================================

#!perl
#Speed 2
$begin = times;
open (OUT, ">FolderList 2");

(shift @ARGV) =~ /(.*):(.*)/;
$a = $1; $b = $2;
print  OUT "$a:$b\n\n";
chdir("$a:$b");
lstat(":");
&dodir;

sub dodir {
    local ($dir) = @_;
    local @files;
    local $item;
    if (-d _) {
        opendir(DIR, ":");
        @files = readdir(DIR);
        close(DIR);
        unless (@files) {print OUT "$dir - empty folder\n"}
        foreach $item (@files) {
            lstat($item);
            $name = "$dir:$item";
            unless (-d _) {print OUT "$name\n";next;}
            chdir($item);
            &dodir($name);
            chdir('::');
        }
    }
}
$finish = times;
print OUT "\n",'Time taken = ',$finish - $begin,"\n";