BEGIN {
  my %mapping = split ' ', <<'END_OF_MAPS';
	  \* *
	  \? ?
	  \\ \\
	  \  \\
	  %  \%
	  _  \_
	  *  %
	  ?  _
END_OF_MAPS

  my $mapping_match = join "|", reverse sort map quotemeta($_), keys %mapping;
  $mapping_match = qr/$mapping_match/; # compile once

  sub pattern_to_like_string {
    my $pattern = shift;      # pattern made of * ? \ and non-specials

    $pattern =~ s/($mapping_match)/$mapping{$1}/g;

    return $pattern;
  }

}