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in reply to Re: Efficient way to verify scalar contents
in thread Efficient way to verify scalar contents

Thanks for replying!

A little confused on the purpose of

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

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length being the passwordLength?

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Re^3: Efficient way to verify scalar contents
by perlfan (Vicar) on Jun 22, 2020 at 05:48 UTC
    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

    [download]

    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);
}

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Re^3: Efficient way to verify scalar contents
by LanX (Saint) on Jun 22, 2020 at 11:40 UTC
    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"
    }
}

    [download]

        
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

    [download]

    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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      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"
    }
}

      [download]

      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

      [download]

      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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        Note that both of your solutions don't report an error for e.g. 'aaaaaaaaa0-' and 'aaaaaaaaaaaaaaaaaaa', which are invalid as per the OP's code.

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