Thanks again. I don't think I'm fully grasping how vec works, even after reading the doc, or the routine using vec to map the bits to the vlans and creating the ranges.

The routine formating numbers like 1,2,3 as 1-3 is great, but doesn't seem to work properly with the octet string example. Of course it won't work with Grandfather's example from what I can see since @ports just contains the VLANs allowed

Trying to shoehorn the previous example into this one:

sub xlat {
  my ($octets) = @_ ;
  return pack('B*', unpack('b*', $octets)) ;
} ;

my $test = '0x4000040000000200800000000000000000000002'
            .'0000000000c004000108008000000000000000000'
            .'00000000000000000000000000000000000000000'
            .'00000000000000000000000000000000000000000'
            .'00000000000000000000000000000000000000000'
            .'00000000000000000000000000000000000000000'
            .'00000000000';
my $bits;

$bits = showbits($test);

my @s = ranges($bits);
print "Ranges: ", join(', ', @s);

$bits = showbits(xlat($test));
@s = ranges($bits);
print join(',',@s);

$bits = showbits(xlat(xlat($test)));
@s = ranges($bits);
print join(',',@s);

sub ranges{
my $test = shift;
my $r = undef ;
my @s = () ;
for my $vn (1..length($test) * 8) {
  if (vec($test, $vn, 1)) {
    if (!defined($r)) { push @s, "$vn-" ; } ;
    $r = $vn ;
  }
  else {
    if (defined($r))  { $s[-1] .= "$r" ;  $r = undef ; } ;
  } ;
} ;
return @s;
}

sub showbits {
  my ($octets) = @_ ;
  my $s = unpack('B*', $octets) ;
  $s =~ s/([01]{8})(?=[01])/$1/g ;
  ranges($s) ;
} ;
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Should, at least in my misunderstanding, produce Ranges: 1,21,54,64,158,200-201,213,231,236,248.

Instead it produces:

Ranges: 1-1, 4-5, 8-8, 10-10, 12-13, 18-18, 20-21, 24-24, 28-291-1,4-5,8-8,10-10,12-13,18-18,20-21,28-291-1,4-5,8-8,10-10,12-13,18-18,20-21,24-24,28-29

Using GrandFather's example

my $ports = '0x4000040000000200800000000000000000000002'
            .'0000000000c004000108008000000000000000000'
            .'00000000000000000000000000000000000000000'
            .'00000000000000000000000000000000000000000'
            .'00000000000000000000000000000000000000000'
            .'00000000000000000000000000000000000000000'
            .'00000000000';
my $basePort = 0;
my @ports;

$ports = substr $ports, 2;

while ($ports) {
    my $octet = hex substr $ports, 0, 2, '';
    my $index = 0;
    
    while ($octet) {
        next unless $octet & 0x80;
        push @ports, $basePort + $index;
    } continue {
        ++$index;
        $octet = ($octet << 1) & 0xff;
    }
    
    $basePort += 8;
}

print join ',', @ports;
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produces: 1,21,54,64,158,200,201,213,231,236,248

After hours of playing with both these examples I managed to confuse myself even more. Can you point out what I'm missing?

Update:After some more tinkering I came up with the following kludge to format Grandfather's example, but something tells me there's a better way to do this. Still haven't figured out how to convert the string properly with vec.

my $ports = '0x4000040000000200800000000000000000000002'
            .'0000000000c004000108008000000000000000000'
            .'00000000000000000000000000000000000000000'
            .'00000000000000000000000000000000000000000'
            .'00000000000000000000000000000000000000000'
            .'00000000000000000000000000000000000000000'
            .'00000000000';
my $basePort = 0;
my @ports;

$ports = substr $ports, 2;

while ($ports) {
    my $octet = hex substr $ports, 0, 2, '';
    my $index = 0;
    
    while ($octet) {
        next unless $octet & 0x80;
        push @ports, $basePort + $index;
    } continue {
        ++$index;
        $octet = ($octet << 1) & 0xff;
    }
    
    $basePort += 8;
}

print join ',', @ports,"\n";
range_format(@ports);

sub range_format{

my (@numbers,$i,$start,$end);
@numbers = @_;

for ($i = 0; $i < @numbers; ++$i){
    
    my $prev = $numbers[$i-1];
    my $next = $numbers[$i+1];
    my $cur = $numbers[$i];
    
    if (($cur+1 == $next) and ($cur-1!= $prev)){
        $start = $cur;
    }
    if (($cur-1 == $prev) and ($cur+1 != $next)){
        $end = $cur;
    }
    if ((defined $start) and (defined $end)){
        print "$start-$end,";
        $start = undef;
        $end = undef;
    }else{
        unless((defined $start)||(defined $end)){print "$cur,";}}
}
}
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