Re: Cleaning the Log

[demerphq]

Actually this is more complicated than a pure regex can handle (perl regexes _may_ be able to handle this, but the code would be scaaaary), this problem is even more difficult than handling balanced constructs and cannot be solved using a formal regular expression.

This is because we cant simply look for .{BS}, as is clear from your sample data such as bnack{BS}{BS}{BS}{BS} where the last {BS} actually remove the 'n'.

But only a slight amount of additional code will allow a working solution....

my $logdata=<<EOLOG;
pass{BS}{BS}{BS}{BS}{BS}{BS}
hee{BS}llo, I'll be bnack{BS}{BS}{BS}{BS}ack next saturday.{BS}{BS}{BS
+}{BS}{BS}{BS}{BS}{BS}{BS}{BS}{BS}{BS}
www.yahoo.com "keyloggers" + "linux"{BS}{BS}{BS}
EOLOG

my $clean;
while ($logdata=~/\G(\{BS}|.)/sg) {
    length ($1)>1 && (length($clean)==0 || substr($clean,length($clean
+)-1,1,""))
    or $clean.=$1;
}
print $clean;

YMMV

Yves / DeMerphq
---
Software Engineering is Programming when you can't. -- E. W. Dijkstra (RIP)

[Aristotle]

perl regexes _may_ be able to handle this, but the code would be scaaaary

I felt like doing something scary. *grin* The trick is to use sexeger - a regex that operates on the reversed string.

s/{BS}/\b/g;
$_ = reverse $_;
my $k = 0;
s/(\010+)(??{ $k += length $+; "([^\010]{0,$k})" })(?{ $k -= length $+
+ })//g;
$_ = reverse $_;

Don't forget to tune in for the next issue of H.R. Giger meets Perl. *grin*

Makeshifts last the longest.