timing.c

Go to the documentation of this file.

/***********************************************************************
 Freeciv - Copyright (C) 1996 - A Kjeldberg, L Gregersen, P Unold
   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 2, 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.
***********************************************************************/
 
/********************************************************************** 
  Measuring times; original author: David Pfitzner <dwp@mso.anu.edu.au>
 
  We assume we have at least ANSI/ISO C timing functions, so
  that we can use:
     clock_t clock() for CPU times
     time_t time() for user-time
  If we have HAVE_GETTIMEOFDAY we use gettimeofday() for user-time
  to get (usually) better resolution than time().
 
  As well as measuring single time intervals, these functions
  support accumulating the time from multiple separate intervals.
 
  Notice the struct timer is an opaque type: modules outside timing.c
  can only use it as a pointer (cf FILE type).  This is done for two
  main reasons:
 
   1. General principle of data hiding and encapsulation
 
   2. Means we don't have to include fc_config.h and possibly system
      specific header files in timing.h.  Such stuff is confined
      inside timing.c.
 
  However there is a disadvantage: any code using a timer must do
  memory allocation and deallocation for it.  Some of the functions
  below are intended to make this reasonably convenient; see function
  comments.
***********************************************************************/
 
#ifdef HAVE_CONFIG_H
#include <fc_config.h>
#endif
 
#include <time.h>
 
#ifdef HAVE_GETTIMEOFDAY
#include <sys/time.h>
#include <unistd.h>
#endif
 
#ifdef HAVE_FTIME
# include <sys/timeb.h>
#endif
 
/* utility */
#include "log.h"
#include "mem.h"
#include "shared.h"             /* TRUE, FALSE */
#include "support.h"
 
#include "timing.h"
 
#ifndef CLOCKS_PER_SEC
#ifdef CLOCKS_PER_SECOND
#define CLOCKS_PER_SEC CLOCKS_PER_SECOND
#else
#define CLOCKS_PER_SEC 1000000  /* wild guess!! */
#endif
#endif
 
#define N_USEC_PER_SEC 1000000L   /* not 1000! :-) */
 
enum timer_state {
  TIMER_STARTED,
  TIMER_STOPPED
};
 
struct timer {
  /* type: */
  enum timer_timetype type;
  enum timer_use use;
  enum timer_state state;
 
  /* this is accumulated time for previous timings: */
  double sec;
  long usec;            /* not always used, in which case zero,
                           or if used may be negative, but >= -1000000 */
 
  /* this is start of current timing, if state == TIMER_STARTED: */
  union {
    clock_t c;
#ifdef HAVE_GETTIMEOFDAY
    struct timeval tv;
#elif HAVE_FTIME
    struct timeb tp;
#else
    time_t t;
#endif
  } start;
};
 
/*******************************************************************/
static void report_clock_failed(struct timer *t)
{
  static bool first = TRUE;
 
  if (first) {
    log_test("clock() returned -1, ignoring timer");
    first = FALSE;
  }
  t->use = TIMER_IGNORE;
}
 
#ifdef HAVE_GETTIMEOFDAY
/*******************************************************************/
static void report_gettimeofday_failed(struct timer *t)
{
  static bool first = TRUE;
 
  if (first) {
    log_test("gettimeofday() returned -1, ignoring timer");
    first = FALSE;
  }
  t->use = TIMER_IGNORE;
}
#elif !defined HAVE_FTIME
/*******************************************************************/
static void report_time_failed(struct timer *t)
{
  static bool first = TRUE;
 
  if (first) {
    log_test("time() returned -1, ignoring timer");
    first = FALSE;
  }
  t->use = TIMER_IGNORE;
}
#endif
 
 
/*******************************************************************/
struct timer *timer_new(enum timer_timetype type, enum timer_use use)
{
  return timer_renew(NULL, type, use);
}
 
/*******************************************************************/
struct timer *timer_renew(struct timer *t, enum timer_timetype type,
                          enum timer_use use)
{
  if (!t) {
    t = (struct timer *)fc_malloc(sizeof(struct timer));
  }
  t->type = type;
  t->use = use;
  timer_clear(t);
  return t;
}
 
/*******************************************************************/
void timer_destroy(struct timer *t)
{
  if (t != NULL) {
    free(t);
  }
}
 
/*******************************************************************/
bool timer_in_use(struct timer *t)
{
  return (t && t->use != TIMER_IGNORE);
}
 
/*******************************************************************/
void timer_clear(struct timer *t)
{
  fc_assert_ret(NULL != t);
  t->state = TIMER_STOPPED;
  t->sec = 0.0;
  t->usec = 0;
}
 
/*******************************************************************/
void timer_start(struct timer *t)
{
  fc_assert_ret(NULL != t);
 
  if (t->use == TIMER_IGNORE) {
    return;
  }
  if (t->state == TIMER_STARTED) {
    log_error("tried to start already started timer");
    return;
  }
  if (t->type == TIMER_CPU) {
    t->start.c = clock();
    if (t->start.c == (clock_t) -1) {
      report_clock_failed(t);
      return;
    }
  } else {
#ifdef HAVE_GETTIMEOFDAY
    int ret = gettimeofday(&t->start.tv, NULL);
 
    if (ret == -1) {
      report_gettimeofday_failed(t);
      return;
    }
#elif defined HAVE_FTIME
    ftime(&t->start.tp);
#else
    t->start.t = time(NULL);
    if (t->start.t == (time_t) -1) {
      report_time_failed(t);
      return;
    }
#endif
  }
  t->state = TIMER_STARTED;
}
 
/*******************************************************************/
void timer_stop(struct timer *t)
{
  fc_assert_ret(NULL != t);
 
  if (t->use == TIMER_IGNORE) {
    return;
  }
  if (t->state == TIMER_STOPPED) {
    log_error("tried to stop already stopped timer");
    return;
  }
  if (t->type == TIMER_CPU) {
    clock_t now = clock();
 
    if (now == (clock_t) -1) {
      report_clock_failed(t);
      return;
    }
    t->sec += (now - t->start.c) / (double)CLOCKS_PER_SEC;
    t->start.c = now;
  } else {
#ifdef HAVE_GETTIMEOFDAY
    struct timeval now;
    int ret = gettimeofday(&now, NULL);
 
    if (ret == -1) {
      report_gettimeofday_failed(t);
      return;
    }
    t->usec += (now.tv_usec - t->start.tv.tv_usec);
    t->sec += (now.tv_sec - t->start.tv.tv_sec);
    if (t->usec < 0) {
      t->usec += N_USEC_PER_SEC;
      t->sec -= 1.0;
    } else if (t->usec >= N_USEC_PER_SEC) {
      long sec = t->usec / N_USEC_PER_SEC;
 
      t->sec += sec;
      t->usec -= sec * N_USEC_PER_SEC;
    }
    t->start.tv = now;
#elif defined HAVE_FTIME
    struct timeb now;
 
    ftime(&now);
    t->usec += 1000 * ((long)now.millitm - (long)t->start.tp.millitm);
    t->sec += now.time - t->start.tp.time;
    if (t->usec < 0) {
      t->usec += N_USEC_PER_SEC;
      t->sec -= 1.0;
    } else if (t->usec >= N_USEC_PER_SEC) {
      long sec = t->usec / N_USEC_PER_SEC;
 
      t->sec += sec;
      t->usec -= sec * N_USEC_PER_SEC;
    }
    t->start.tp = now;
#else
    time_t now = time(NULL);
 
    if (now == (time_t) -1) {
      report_time_failed(t);
      return;
    }
    t->sec += difftime(now, t->start.t);
    t->start.t = now;
#endif
  }
  t->state = TIMER_STOPPED;
}
 
/*******************************************************************/
double timer_read_seconds(struct timer *t)
{
  fc_assert_ret_val(NULL != t, -1.0);
 
  if (t->use == TIMER_IGNORE) {
    return 0.0;
  }
  if (t->state == TIMER_STARTED) {
    timer_stop(t);
    t->state = TIMER_STARTED;
  }
  return t->sec + t->usec / (double)N_USEC_PER_SEC;
}
 
/*******************************************************************/
void timer_usleep_since_start(struct timer *t, long usec)
{
#ifdef HAVE_GETTIMEOFDAY
  int ret;
  struct timeval tv_now;
  long elapsed_usec;
  long wait_usec;
 
  fc_assert_ret(NULL != t);
 
  ret = gettimeofday(&tv_now, NULL);
 
  if ((ret == -1)
      || (t->type != TIMER_USER)
      || (t->use != TIMER_ACTIVE)
      || (t->state != TIMER_STARTED)) {
    fc_usleep(usec);
    return;
  }
 
  elapsed_usec =
    (tv_now.tv_sec - t->start.tv.tv_sec) * N_USEC_PER_SEC +
    (tv_now.tv_usec - t->start.tv.tv_usec);
  wait_usec = usec - elapsed_usec;
 
  if (wait_usec > 0)
    fc_usleep(wait_usec);
#elif HAVE_FTIME
  struct timeb now;
  long elapsed_usec, wait_usec;
 
  ftime(&now);
 
  elapsed_usec = (now.time - t->start.tp.time) * N_USEC_PER_SEC
    + (now.millitm - t->start.tp.millitm);
  wait_usec = usec - elapsed_usec;
 
  if (wait_usec > 0) {
    fc_usleep(wait_usec);
  }
#else
  fc_usleep(usec);
#endif
}