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Re: Searching in binary files

by Corion (Patriarch)
on Dec 14, 2005 at 18:05 UTC ( [id://516709]=note: print w/replies, xml ) Need Help??


in reply to Searching in binary files

Use a sliding window:

my @lines;
$/ = \80; # assume a block size of 80

while (<$file>) {
  push @lines, $_;

  my $str = join "", @lines;
  if ($str =~ /searchword/) {
    my $loc = tell $file - pos $str;
    print "Found a match starting after $loc.\n";
  };

  if (@lines > 2) {
    shift @lines
  };
};

[download]

Instead of looking for a match in just one "line", you look for a match in the "line" and the "line" after it.

Replies are listed 'Best First'.
Re^2: Searching in binary files
by crenz (Priest) on Dec 14, 2005 at 18:25 UTC

    Danke nach Frankfurt!

    There are a few bugs in your code, though. I changed the if to a while loop and fixed a few other problems:

        while ($str =~ /searchword/g) {
        my $loc = tell($fh) - length($str) + pos($str);
        print "Found a match starting after $loc.\n";
    }

    [download]

    Update: That doesn't quite work either... it finds too many occurrences...

[reply]
[d/l]
[select]
          while ($str =~ /$pattern/g) {
        my $loc = tell($fh) - length($str) + pos($str) - length($patte
+rn);
        print "Found a match starting after $loc.\n";
    }

      [download]
[reply]
[d/l]

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