#define __NO_STRING_INLINES

#include <sys/resource.h>
#include <sys/time.h>
#include <stdio.h>
#include <assert.h>
#include <stdlib.h>

char s1[] = "abcdefghijklmnopqrstuvwxyz";

void
test_my_memcmp (char *s1, int i, int test, int len)
{
  char s2[2 * len + 1];
  int j, k;

  for (k = i; k <= len + 1; k++)
    for (j = 0; j < len; j++)
      {
        memcpy (s2 + j, s1, len + 1);
        s2[i+j] += test;
        assert (my_memcmp (s2 + j, s1, k) == (k != i ? test : 0));
      }
}

void
speed_libc (char *s1, int i, int test, int len)
{
  char s2[2 * len + 1];
  int j, k;

  for (k = i; k <= len + 1; k++)
    for (j = 0; j < len; j++)
      {
        memcpy (s2 + j, s1, len + 1);
        s2[i+j] += test;
        s2[0] = memcmp (s2 + j, s1, k);
      }
}

void
speed_builtin (char *s1, int i, int test, int len)
{
  char s2[2 * len + 1];
  int j, k;

  for (k = i; k <= len + 1; k++)
    for (j = 0; j < len; j++)
      {
        memcpy (s2 + j, s1, len + 1);
        s2[i+j] += test;
        s2[0] = __builtin_memcmp (s2 + j, s1, k);
      }
}

void
speed_memcmp (char *s1, int i, int test, int len)
{
  char s2[2 * len + 1];
  int j, k;

  for (k = i; k <= len + 1; k++)
    for (j = 0; j < len; j++)
      {
        memcpy (s2 + j, s1, len + 1);
        s2[i+j] += test;
        s2[0] = my_memcmp (s2 + j, s1, k);
      }
}

void
speed_loop (char *s1, int i, int test, int len)
{
  char s2[2 * len + 1];
  int j, k;

  for (k = i; k <= len + 1; k++)
    for (j = 0; j < len; j++)
      {
        memcpy (s2 + j, s1, len + 1);
        s2[i+j] += test;
        s2[0] = 0;
      }
}

double
do_test (int repetitions, void (*test_function) (char *, int, int, int))
{
  int len = strlen(s1);
  int i, h;
  struct rusage r1, r2;

  getrusage(RUSAGE_SELF, &r1);

  while (repetitions--)
    for (h = 0; h < len; h += 5)
      for (i = h; i < len; i++)
        {
          test_function (s1 + h, i - h, -1, len);
          test_function (s1 + h, i - h, 0, len);
          test_function (s1 + h, i - h, 1, len);
        }

  getrusage(RUSAGE_SELF, &r2);
  return (r2.ru_utime.tv_sec - r1.ru_utime.tv_sec) +
	 (r2.ru_utime.tv_usec - r1.ru_utime.tv_usec) / 1000000.0;
}

main(int argc, char **argv)
{
  int repetitions = (argc == 1) ? 100 : atoi(argv[1]);

  do_test (1, test_my_memcmp);

  printf ("%d repetitions\n\n", repetitions);
  printf ("Testing custom memcmp .....");
  fflush (stdout);
  printf (" done, %10.3f seconds\n", do_test (repetitions, speed_memcmp));

  printf ("Testing libc memcmp .......");
  fflush (stdout);
  printf (" done, %10.3f seconds\n", do_test (repetitions, speed_libc));

  printf ("Testing builtin memcmp ....");
  fflush (stdout);
  printf (" done, %10.3f seconds\n", do_test (repetitions, speed_builtin));

  printf ("Testing loop overhead .....");
  fflush (stdout);
  printf (" done, %10.3f seconds\n", do_test (repetitions, speed_loop));

  exit (0);
}