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Re: Efficient way to verify scalar contents

by LanX (Cardinal)
on Jun 22, 2020 at 04:59 UTC ( #11118336=note: print w/replies, xml ) Need Help??


in reply to Efficient way to verify scalar contents

Hi, some untested pseudo code

I see it as a rules matrix to be checked.

I'd take

$index= min( int(length /4), 5 )

And an array of arrays @rules for lookup.

The rules array would contain subs which all must return true for the password to pass.

Like $letter = sub {  /[a-z]/i }

(This will test against $_ )

So $rules[3] = [ $letter, $number ]

$rules[1] = [ $forbidden ]

All you need to do now is too loop over all rules and fail if one entry returns false.

HTH! :)

PS instead of code refs one might also store regex refs with qr//.

But why blocking the way to more complicated rules?

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery

Replies are listed 'Best First'.
Re^2: Efficient way to verify scalar contents
by x_stream3m (Initiate) on Jun 22, 2020 at 05:15 UTC

    Thanks for replying!

    A little confused on the purpose of

    $index= min( int(length /4), 5 )

    length being the passwordLength?

      It appears to be the index of the check based on length of the supplied password. You have 4 valid conditions that lead to additional checks; the 5th one is always invalid. Indexes 0, 1, 2, and 3 elements of the array of subroutine references he suggests will call the function appropriate for the length.
      when ($_ >= 8 && $_ <= 11) # $index here is min( 2, 5), so 2 when ($_ >= 12 && $_ <= 15) { # $index here is min( 3, 5), so 3 when ($_ >= 16 && $_ <= 19) { # $index here is min( 4, 5), so 4 when ($_ >= 20) { # $index here is min( 5+,5), so alw +ays bounded at 5

      TBH it's not clear enough to make great sense to me, but he appears to be suggesting that you put your ranges into buckets based on the formula he gave; for a length of 20 or more, you're always going to fall into bucket 5 (or perhaps element 3) of your array of checks. This is actually a pretty good way to determine a bucket, so then you can have an array of checks; or to make it more clear, a hash:
      my %check_dispatch = ( 2 => sub { ... }, # or better, define in named subs and, => \&check1 +, etc 3 => sub { ... }, 4 => sub { ... }, 5 => sub { ... }, ); my $pw = $_; my $index = min( (length $pw)/4, 5); if ($check_dispatch{$index} and 'CODE' eq ref $check_dispatch{$index}) + { die if not $check_dispatch{$index}->($pw); }
      As I said it was pseudocode =)

      I meant something like this:

      use strict; use warnings; use Data::Dump qw/pp dd/; use List::Util qw/min/; sub pw_not_ok { my $pw = shift; my $short = sub { "is too short" }; my $lowercase = sub { /[a-z]/ ? "" : "has no lowercase character" }; my $uppercase = sub { /[A-Z]/ ? "" : "has no uppercase character" }; ### FIXED my $number = sub { /[0-9]/ ? "" : "has no number" }; my $special = sub { if ( /[\x21-\x2F]/ || /[\x3A-\x40]/ || /[\x5B-\x60]/ || /[\x7B-\x7E]/ ) { return ""; } else { return "has no special characters"; } }; my $pass = sub {""}; my @rules_for_class = ( [ $short ], [ $short ], [ $lowercase, $uppercase, $number ,$special ], [ $lowercase, $uppercase, $number ], [ $lowercase, $uppercase ], [ $pass ] ); my $len = length $pw; my $idx = min(int($len/4),5); for my $rule ( @{ $rules_for_class[$idx] } ) { $_ = $pw; if ( my $err = $rule->() ) { return $err; } } return; } # --------- Tests for my $pw ( "A" x 3 , "A" x 7 , "A" x 11, "a" x 5 . "A" x 3, "a" x 5 . "A" x 3 . "1", "a" x 5 . "A" x 3 . "1" .":", "a" x 24, ){ if ( my $err = pw_not_ok($pw) ){ warn "ERROR: $pw is $err\n"; } else { print "OK: $pw\n" } }

      ERROR: AAA is is too short ERROR: AAAAAAA is is too short ERROR: AAAAAAAAAAA is has no lowercase character ERROR: aaaaaAAA is has no number ERROR: aaaaaAAA1 is has no special characters OK: aaaaaAAA1: OK: aaaaaaaaaaaaaaaaaaaaaaaa

      Cheers Rolf
      (addicted to the Perl Programming Language :)
      Wikisyntax for the Monastery

      UPDATE

      see Re^6: Efficient way to verify scalar contents

        Though for the sake of readability I'd rather go for a hash of boundaries.

        you may also want to limit the max length of your password.

        use strict; use warnings; use Data::Dump qw/pp dd/; use List::Util qw/min/; sub pw_not_ok { my $pw = shift; my $short = sub { "is too short" }; my $lowercase = sub { /[a-z]/ ? "" : "has no lowercase character" }; my $uppercase = sub { /[A-Z]/ ? "" : "has no uppercase character" }; ### UPDATE +D my $number = sub { /[0-9]/ ? "" : "has no number" }; my $special = sub { if ( /[\x21-\x2F]/ || /[\x3A-\x40]/ || /[\x5B-\x60]/ || /[\x7B-\x7E]/ ) { return ""; } else { return "has no special characters"; } }; my $pass = sub {""}; my %rules_by_max_length = ( 7 => [ $short ], 11 => [ $lowercase, $uppercase, $number ,$special ], 15 => [ $lowercase, $uppercase, $number ], 19 => [ $lowercase, $uppercase ], 50 => [ $pass ] ); my $len = length $pw; return "too long" if $len >= 50; my @boundaries = sort { $a <=> $b } keys %rules_by_max_length; for my $boundary ( @boundaries ) { next if $len > $boundary; my $rules = $rules_by_max_length{$boundary}; for my $rule ( @$rules ) { $_ = $pw; if ( my $err = $rule->() ) { return $err; } } } return; } # --------- Tests for my $pw ( "A" x 3 , "A" x 7 , "A" x 11, "a" x 5 . "A" x 3, "a" x 5 . "A" x 3 . "1", "a" x 5 . "A" x 3 . "1" .":", "a" x 24, "a" x 100, ){ if ( my $err = pw_not_ok($pw) ){ warn "ERROR: $pw is $err\n"; } else { print "OK: $pw\n" } }

        ERROR: AAA is is too short ERROR: AAAAAAA is is too short ERROR: AAAAAAAAAAA is has no lowercase character ERROR: aaaaaAAA is has no number ERROR: aaaaaAAA1 is has no special characters ERROR: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa +aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa is too long OK: aaaaaAAA1: OK: aaaaaaaaaaaaaaaaaaaaaaaa

        Cheers Rolf
        (addicted to the Perl Programming Language :)
        Wikisyntax for the Monastery

        UPDATE

        see Re^6: Efficient way to verify scalar contents

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