if( $user->permits( FOO ) )

##</code><code>##

if( $user->permits( FOO | BAR | BAZ ) )

##</code><code>##

package User;
...
use constant FOO => 1 << 1;
use constant BAR => 1 << 2;
use constnat BAZ => 1 << 3;
...
sub permits { 
    my ($self, $mask) = @_;
    return ($self->{perms} & $mask);
}

##</code><code>##

package FriedoBits; 

use strict;

use overload '|' => \&bitor;
use overload '&' => \&bitand;

sub bitor { 
    my ($a, $b) = @_;

    my $new = [ ];
    for(0..3) { 
        $new->[$_] = ( $a->[$_] | $b->[$_] );
    }

    return __PACKAGE__->new( $new );
}

sub bitand { 
    my ($a, $b) = @_;

    my $new = [ ];
    for(0..3) { 
        $new->[$_] = ( $a->[$_] & $b->[$_] );
    }

    return __PACKAGE__->new( $new );
}

sub new {
    return bless $_[1], ref($_[0]) || $_[0];
}


use constant PERM_0000 => FriedoBits->new( 
  [ 0x00000000, 0x00000000, 0x00000000, 0x00000001 ] );
use constant PERM_0001 => FriedoBits->new( 
  [ 0x00000000, 0x00000000, 0x00000000, 0x00000002 ] );
use constant PERM_0002 => FriedoBits->new( 
  [ 0x00000000, 0x00000000, 0x00000000, 0x00000004 ] );
use constant PERM_0003 => FriedoBits->new( 
  [ 0x00000000, 0x00000000, 0x00000000, 0x00000008 ] );
use constant PERM_0004 => FriedoBits->new( 
  [ 0x00000000, 0x00000000, 0x00000000, 0x00000010 ] );
use constant PERM_0005 => FriedoBits->new( 
  [ 0x00000000, 0x00000000, 0x00000000, 0x00000020 ] );
...
use constant PERM_0125 => FriedoBits->new( 
  [ 0x20000000, 0x00000000, 0x00000000, 0x00000000 ] );
use constant PERM_0126 => FriedoBits->new( 
  [ 0x40000000, 0x00000000, 0x00000000, 0x00000000 ] );
use constant PERM_0127 => FriedoBits->new( 
  [ 0x80000000, 0x00000000, 0x00000000, 0x00000000 ] );

1;

##</code><code>##

Benchmark: timing 100000 iterations of BigInt...
    BigInt: 188 wallclock secs 
(168.07 usr +  0.36 sys = 168.43 CPU) @ 593.72/s (n=100000)

Benchmark: timing 100000 iterations of BigIntGMP...
 BigIntGMP: 44 wallclock secs 
(38.50 usr +  0.13 sys = 38.63 CPU) @ 2588.66/s (n=100000)

Benchmark: timing 100000 iterations of FriedoBits...
FriedoBits:  3 wallclock secs ( 3.11 usr +  0.01 sys =  3.12 CPU) @ 32051.28/s (n=100000)