Search::Equidistance - Perl extension for blah blah blah

  use Search::Equidistance;
  decode ($search_string, $MAXSKIP, $file);

  This should be the abstract for Search::Equidistance.
  The abstract is used when making PPD (Perl Package Description) files.
  If you don't want an ABSTRACT you should also edit Makefile.PL to
  remove the ABSTRACT_FROM option.

  First converts file to contiguous_single_line text composed of
  alphabets and digits only. Then for skip 1(normal text) thru MAXSKIP,
  generates partial texts, searches the string (case-insensitive, forward,
  and reverse) and lists the find as follows. 

  Example output:

  $ run_decode.pl ABC 5 code.10000
  [Skip=3]
  <0:3334>CBA(405)ABC(811)
  <1:3333>CBA(1249)
  [Skip=4]
  <2:2500>CBA(900)
  [Skip=5]
  <0:2000>CBA(1115)
  <4:2000>ABC(406)CBA(1827)

  "=== String ABC are found 7 times (forward & reverse) ==="

  where
  [Skip=3] has 3 partial texts (text-0, text-1, text-2)
  <0:3334> means text-0 (of length 3334),
           code.10000 being length 10000
  CBA(405)ABC(811) => string CBA found in position 405, and
                      ABC in position 811 (starting position 0)

package Search::Equidistance;

use 5.008;
use strict;
use warnings;

require Exporter;

our @ISA = qw(Exporter);

# Items to export into callers namespace by default. Note: do not export
# names by default without a very good reason. Use EXPORT_OK instead.
# Do not simply export all your public functions/methods/constants.

# This allows declaration	use Search::Equidistance ':all';
# If you do not need this, moving things directly into @EXPORT or @EXPORT_OK
# will save memory.
our %EXPORT_TAGS = ( 'all' => [ qw() ] );

our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );

our @EXPORT = qw(decode);
	
our $VERSION = '0.01';

# Preloaded methods go here.

sub decode {
croak("Usage: decode(string, max-skip, file) ") unless(@_ == 3);

my ($find, $MAXSKIP, $file) = @_;
my $rfind = reverse($find);
open F, $file or die "No such file $file: $!\n";

my $line = join "", <F>;
$line =~ s/(\W|\n)//g;

my ($sum_count, $n, $found, $sm, $i, $end, $match, $len, $pos, $count);

$sum_count = 0;
for $n (1..$MAXSKIP) {
	$found = 0;
	$sm = $n - 1;
	for $i (0..$sm) {
		$end = $sm - $i;
		$match = "\.\{0,$i\}\(\.{0,1}\)\.\{0\,$end\}";
		($_ = $line) =~ s/$match/$1/g;
		$len = length;
		$pos = 0;
		$count = 0;
		while (/$find|$rfind/i) {
			$found++;
			print "[Skip=$n]\n" if ($found == 1);
			$count++;
			print "<$i:$len>" if ($count == 1);
			$pos += length($`);
			print "$&($pos)";
			$pos += length($&);
			s/$`$&//;
		}
		print "\n" if ($count > 0);
		$sum_count += $count;
	}
}
print "\n=== String $find are found $sum_count times (forward & reverse) ===\n";

}

1;
__END__
# Below is stub documentation for your module. You'd better edit it!