#!/usr/bin/perl -p
#
# save-combine - filter and combine output from ipset(1) save
#
# (c)2026 Corwin Brust <corwin@bru.st>
#
# You may use this program under the terms of the GNU Public License version three (3) or, at your option, any later version of that license. (GPLv3+)
#
# Use a flat-file "DB" of ipset per row in the form NAME MAX
# Drop create/add lines for any set not mentioned in the DB
# Take DB file-name from first program arg, otherwise "ipset-counts.txt"
# Input is expected on stdin in the same format as output by ipset save
#

sub max2 {
  my $val = $_[0] || 1;
  my $rv = 2;
  $rv *= 2 until $rv > $val;
  return $rv;
}

BEGIN {
	my $SET_COUNTS = @ARGV ? shift : q(max-counts.txt);
       	open my$FH,q(<),$SET_COUNTS or die $!;
	while(<$FH>) {
		chomp;
		my($k,$v)=split;
		$m{$k}=max2( $v ) if $k and $v
	}
}

if(/^create (\S+)/) {
	if(exists $h{$1}) {
		$_ = '';
	} elsif(exists $m{$1}) {
		$h{$1} = 1; # don't reissue creates
		$n = $1; # grab the name
		$v = $m{$n}; # lookup max
		s/^create $n (.*?maxelem) \d+ (.*)$/create $n $1 $v $2/
		    and warn qq[set $n=$v]
	}
	else {
		$_ = ''; # skip create when no max defined
	}
}
elsif(/^add (\S+)/)
{
    # $_ = '' unless exists $m{$1};
    if (exists $m{$1}) {
	s/$/ -exist/; # make dup-safe
    } else {
	$_ = '';
    }
}