regex contest with Intel(R) Core(TM) i7-5820K CPU @ 3.30GHz

test.cc

/* 
$ /usr/bin/g++ -O2 -std=c++11
$ time ./a.out
0.52s user 0.00s system 99% cpu 0.525 total
*/

#include <regex>
#include <string>
#include <iostream>

using namespace std;

int main() {
  string s(1048576, 'a');
  s.back() = 'b';
  string re(400, ' ');
  for (int i = 0; i < 400; i+=4) {
    re[i] = 'a';
    re[i+1] = 'a';
    re[i+2] = '?';
    re[i+3] = 'b';
  }
  regex r(re);
  for(int i = 0; i < 10; i++)
    regex_search(s, r);
  return 0;
}

test.ml

(* $ corebuild -pkg core,re.posix test.native 
   $ time ./test.native 
   
   0.09s user 0.00s system 95% cpu 0.090 total
*)

open Core.Std

let str = 
  let len = 1048576 in
  let str = String.create len in
  String.fill str ~pos:0 ~len:len 'a';
  str.[len - 1] <- 'b';
  str

let pat = 
  let str = String.create 400 in
  let i = ref 0 in
  while !i < 400 do 
    str.[!i] <- 'a';
    str.[!i + 1] <- 'a';
    str.[!i + 2] <- '?';
    str.[!i + 3] <- 'b';
    i := !i + 4 
  done;
  str

let compiled_pat = Re_posix.compile_pat pat

let () = 
  for i = 0 to 10 do
    ignore (Re.execp compiled_pat str)
  done

test_re2.cc

/* /usr/bin/g++ -O2 -std=c++11 b.cc -lre2 && time ./a.out 
0.12s user 0.00s system 99% cpu 0.121 total
*/

#include <string>
#include <iostream>
#include <re2/re2.h>
 
using namespace std;
 
int main() {
  string s(1048576, 'a');
  s.back() = 'b';
  string re(400, ' ');
  for (int i = 0; i < 400; i+=4) {
    re[i] = 'a';
    re[i+1] = 'a';
    re[i+2] = '?';
    re[i+3] = 'b';
  }
  re2::RE2 r(re);
  for(int i = 0; i < 10; i++)
    RE2::PartialMatch(s, r);
  return 0;
}