#!/usr/bin/perl

use Benchmark qw( timethese );

$rCODE = reverse($CODE = << 'END');
int f = 1; /* comments /* used here */
if (f/1 == f) { /* you can use / here */
  printf("this is /* not /* a */ comment");
}
END

timethese(-5, {
  sexeger => q{
($last) = scalar reverse($rCODE =~ m{
  ^
  (?: " [^"]* " | [^*]/ | [^/"]+ )*
  ( /(?:\*+[^*]*[^/*])*\*+[^*]*\*/ )
  (?: " [^"]* " | [^*]/ | [^/"]+ | /(?:\*+[^*]*[^/*])*\*+[^*]*\*/ )*
  $
}x);
},
  normal => q{
($last) = $CODE =~ m{
  ^
  (?: " [^"]* " | /\*[^*]*\*+(?:[^/*][^*]*\*+)*/ | /[^*] | [^/"]+ )*
  ( /\*[^*]*\*+(?:[^/*][^*]*\*+)*/ )
  (?: " [^"]* " | /[^*] | [^/"]+ )*
  $
}x;
}});

__END__
Benchmark: running normal, sexeger, each for at least 5 CPU seconds...
    normal: 14 wallclock secs ( 8.99 usr +  0.00 sys =  8.99 CPU) @  3.11/s (n=28)
   sexeger:  8 wallclock secs ( 5.00 usr +  0.00 sys =  5.00 CPU) @ 1078.00/s (n=5390)