That sounds positive. You should be able to avoid most of the overhead of
writing the file. The general idea is that you are "updating in place" rather
than writing out the whole file.
Something like below is what I was thinking, but it isn't tested! Make sure
you have a copy of your input file. Oh, and I haven't thought about "wide"
characters which may influence how some of this works.
Cheers,
Claude.
open(my $fh, "+<", $theFileName) or die "open: $!";
my $startOfLine = tell($fh) or die "tell: $!;
while (defined(my $line = <$fh>))
{
if ($line has content that needs to change)
{
<change $line, making sure the length (in bytes) doesn't change>
seek($fh, $startOfLine, 0) or die "seek: $!";
print $fh $line;
}
$startOfLine = tell($fh) or die "tell: $!;
}
close($fh);
-----Original Message-----
From: Tom Reed <t...@dkinbox.com>
Sent: Wednesday, May 31, 2023 9:33 AM
To: Claude Brown <claude.br...@gigacomm.net.au>
Cc: beginners@perl.org
Subject: RE: storage types for big file
> Do you have the option to "seek" to the correct place in the file to make
> your changes? For example, perhaps:
>
> - Your changes are few compared to writing out the whole file
> - Your changes do not change the size of the file (or you can pad line-end
> with spaces)
>
1. each time just changes few lines, not the full file.
2. it has file size changed, but yes I can pad line-end with space.
So what's the further?
Thanks
--
Sent from https://dkinbox.com/
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