Hi there,
I am Gerard, 1st year student of Perl at the university.
I came across some lines of code from a script done by an ex student that left uni and did not left any explanation of the code.
The only thing I know is that the script reads an external file that contains 2 lines of code.
The 1st and 2nd lines on this file are:
BEGIN!! Addr:* Name:John
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4DZWJMZMX44ZiaZ4 END!!
I think it compares both lines on the script and return true if equal.
Could some one please explain me better, and how can I create the second line? is it in HExadecimal or what?
Below is the code on the script:
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$const{'code_validate'} = sub {
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my $p_decode = sub {
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local $_;
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my $code = defined($_[0]) ? $_[0] : '';
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my %map = ();
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my $i = 0;
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foreach (48..57,65..90,97..122) {
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$map{chr($_)} = $i % 16;
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$i++;
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}
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$code =~ s!\s|\r|\n|\015|\012!!sg;
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my $text = '';
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my $frag = '';
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$i = 0;
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while ($frag = substr($code, $i, 2)) {
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$i += 2;
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my $chn = 16 * $map{substr($frag,0,1)};
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$chn += $map{substr($frag,1,1)};
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my $ch = chr($chn);
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$text .= $ch;
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}
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$text = unpack('u',$text);
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return $text;
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};
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local $_;
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my $code = defined($_[0]) ? $_[0] : '';
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return 0 unless ($code);
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my $is_valid = 0;
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$code =~ s!BEGIN!!sg;
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$code =~ s!END!!sg;
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if ($code =~ m!^\s*(.*)\s*\-\s*(.*?)\s*$!s) {
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my ($pub, $pri) = ($1,$2);
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$pri = &$p_decode($pri);
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$pub =~ s!(\s|\r|\n)!!sg;
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$pri =~ s!(\s|\r|\n)!!sg;
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if ($pub eq $pri) {
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$is_valid = 1;
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}
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}
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return $is_valid;
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};
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Thanks for all your help
Gerard
