/* Utilities for benchmarks.
   Copyright (C) 2018-2023 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

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

struct timings_state
{
  /* Filled when the timings start.  */
  struct timeval real_start;
  struct timeval user_start;
  struct timeval sys_start;
  /* Filled when the timings end.  */
  long real_usec;
  long user_usec;
  long sys_usec;
};

static void
timing_start (struct timings_state *ts)
{
  struct rusage usage;

  getrusage (RUSAGE_SELF, &usage);
  ts->user_start = usage.ru_utime;
  ts->sys_start = usage.ru_stime;

  gettimeofday (&ts->real_start, NULL);
}

static void
timing_end (struct timings_state *ts)
{
  struct timeval real_end;
  struct rusage usage;

  gettimeofday (&real_end, NULL);

  getrusage (RUSAGE_SELF, &usage);

  ts->real_usec = (real_end.tv_sec - ts->real_start.tv_sec) * 1000000
                  + real_end.tv_usec - ts->real_start.tv_usec;
  ts->user_usec = (usage.ru_utime.tv_sec - ts->user_start.tv_sec) * 1000000
                  + usage.ru_utime.tv_usec - ts->user_start.tv_usec;
  ts->sys_usec = (usage.ru_stime.tv_sec - ts->sys_start.tv_sec) * 1000000
                 + usage.ru_stime.tv_usec - ts->sys_start.tv_usec;
}

static void
timing_output (const struct timings_state *ts)
{
  printf ("real %10.6f\n", (double)ts->real_usec / 1000000.0);
  printf ("user %7.3f\n", (double)ts->user_usec / 1000000.0);
  printf ("sys  %7.3f\n", (double)ts->sys_usec / 1000000.0);
}