Might be easier to use something like 
  $ds = unpack "B*", $data;
  $ps = unpack "B*", $pattern;
  ($x = index $ds,$ps) >= 0 and print "Match at bit offset $x\n";

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Update: how can a 3-line snippet have a bug?

+++++++++ In theory, theory describes reality, but in reality it doesn't.

In reply to Re: Binary File Manipulation across Byte boundaries by zude
in thread Binary File Manipulation across Byte boundaries by tperdue

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