Re: trying again: automaticly image width and height

On Sat, 12 May 2001, Janning Vygen wrote:

> Am Samstag, 12. Mai 2001 00:41 schrieb Peter Flynn:
> > > heres my question again: i tried some extension from lunatech to
> > > insert width and height into the img tags of a html nod set. i cant
> > > find the lunatech extensions in the internet again, so i cant ask
> > > them why the i get an input stream error after about 400 images.
> >
> > Memory leaks?
> 
> i am running linux

That doesn't mean anything. Memory leaks are nearly always a problem with
the _program_, not the operating system. The following trivial program
would leak memory on *any* system, for example. Watch it with 'ps' or
'top' and you can see it steadily grow. 


#!/usr/bin/perl -w

use strict;
use Image::Size;

local $/;
my $data = {};
foreach (@ARGV) {
    next if (! -f $_);
    if (not open(DATA_FILE,$_)) {
        warn("Could not open $_: $!\n");
        next;
    }
    $data->{$_} = <DATA_FILE>;
    close(DATA_FILE);
    print ("$_ : " . length($data->{$_}) . " bytes\n");
    my $image = $data->{$_};
    my ($width,$height,$type) = imgsize(\$image);
    next if (not defined $width);
    print ("   height - $height, width - $width, type - $type\n");
    sleep 1;
}

If you are using a Java based tool, odd are heavy that you are running in
the default 64Mb heap - which goes boom fairly quickly if you have a leak.
A work around (assuming you have enough real/virtual mem for the number of
images you are going to be handling) is to invoke java with the -Xmx (see
'java -X' for info on it) flag and increase the heap space. Another work
around is run 'non-persistently'. IOW if you are processing many documents
and that is why you need 400+ images processed but no individual document
has very many, reinvoke the *entire* program for each document processed.

#!/usr/bin/perl -w
use strict;

foreach my $document (@ARGV) {
	# Call program here using
        # the 'system' call with whatever
        # the appropriate parameters are.
        system('java','program.jar',$document);
}

-- 
Benjamin Franz

"Premature optimization is the root of all evil in programming."
                                         ---C.A.R. Hoare





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