/* Wrappers for platform timing functions.
   Copyright (C) 2003, 2007, 2009, 2011 Free Software Foundation, Inc.

This file is part of the GNU Fortran runtime library (libgfortran).

Libgfortran 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.

Libgfortran 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.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

#ifndef LIBGFORTRAN_TIME_H
#define LIBGFORTRAN_TIME_H

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <errno.h>

/* The time related intrinsics (DTIME, ETIME, CPU_TIME) to "compare
   different algorithms on the same computer or discover which parts
   are the most expensive", need a way to get the CPU time with the
   finest resolution possible. We can only be accurate up to
   microseconds.

   As usual with UNIX systems, unfortunately no single way is
   available for all systems.  */

#ifdef TIME_WITH_SYS_TIME
#  include <sys/time.h>
#  include <time.h>
#else
#  if HAVE_SYS_TIME_H
#    include <sys/time.h>
#  else
#    ifdef HAVE_TIME_H
#      include <time.h>
#    endif
#  endif
#endif

#ifdef HAVE_SYS_TYPES_H
     #include <sys/types.h>
#endif

/* The most accurate way to get the CPU time is getrusage (). */
#if defined (HAVE_GETRUSAGE) && defined (HAVE_SYS_RESOURCE_H)
#  include <sys/resource.h>
#endif  /* HAVE_GETRUSAGE && HAVE_SYS_RESOURCE_H  */

/* The most accurate way to get the CPU time is getrusage ().
   If we have times(), that's good enough, too.  */
#if !defined (HAVE_GETRUSAGE) || !defined (HAVE_SYS_RESOURCE_H)
/* For times(), we _must_ know the number of clock ticks per second.  */
#  if defined (HAVE_TIMES) && (defined (HZ) || defined (_SC_CLK_TCK) || defined (CLK_TCK))
#    ifdef HAVE_SYS_PARAM_H
#      include <sys/param.h>
#    endif
#    if defined (HAVE_SYS_TIMES_H)
#      include <sys/times.h>
#    endif
#    ifndef HZ
#      if defined _SC_CLK_TCK
#        define HZ  sysconf(_SC_CLK_TCK)
#      else
#        define HZ  CLK_TCK
#      endif
#    endif
#  endif  /* HAVE_TIMES etc.  */
#endif  /* !HAVE_GETRUSAGE || !HAVE_SYS_RESOURCE_H  */


#if defined (__GNUC__) && (__GNUC__ >= 3)
#  define ATTRIBUTE_ALWAYS_INLINE __attribute__ ((__always_inline__))
#else
#  define ATTRIBUTE_ALWAYS_INLINE
#endif

static inline int gf_cputime (long *, long *, long *, long *) ATTRIBUTE_ALWAYS_INLINE;

/* Helper function for the actual implementation of the DTIME, ETIME and
   CPU_TIME intrinsics.  Returns 0 for success or -1 if no
   CPU time could be computed.  */

#ifdef __MINGW32__

#define WIN32_LEAN_AND_MEAN
#include <windows.h>

static int
gf_cputime (long *user_sec, long *user_usec, long *system_sec, long *system_usec)
{
  union {
    FILETIME ft;
    unsigned long long ulltime;
  } kernel_time,  user_time;

  FILETIME unused1, unused2;

  /* No support for Win9x.  The high order bit of the DWORD
     returned by GetVersion is 0 for NT and higher. */
  if (GetVersion () >= 0x80000000)
    {
      *user_sec = *system_sec = 0;
      *user_usec = *system_usec = 0;
      return -1;
    }

  /* The FILETIME structs filled in by GetProcessTimes represent
     time in 100 nanosecond units. */
  GetProcessTimes (GetCurrentProcess (), &unused1, &unused2,
              	   &kernel_time.ft, &user_time.ft);

  *user_sec = user_time.ulltime / 10000000;
  *user_usec = (user_time.ulltime % 10000000) / 10;

  *system_sec = kernel_time.ulltime / 10000000;
  *system_usec = (kernel_time.ulltime % 10000000) / 10;
  return 0;
}

#else

static inline int
gf_cputime (long *user_sec, long *user_usec, long *system_sec, long *system_usec)
{
#if defined (HAVE_GETRUSAGE) && defined (HAVE_SYS_RESOURCE_H)
  struct rusage usage;
  int err;
  err = getrusage (RUSAGE_SELF, &usage);

  *user_sec = usage.ru_utime.tv_sec;
  *user_usec = usage.ru_utime.tv_usec;
  *system_sec = usage.ru_stime.tv_sec;
  *system_usec = usage.ru_stime.tv_usec;
  return err;

#elif defined HAVE_TIMES
  struct tms buf;
  clock_t err;
  err = times (&buf);
  *user_sec = buf.tms_utime / HZ;
  *user_usec = buf.tms_utime % HZ * (1000000 / HZ);
  *system_sec = buf.tms_stime / HZ;
  *system_usec = buf.tms_stime % HZ * (1000000 / HZ);
  if ((err == (clock_t) -1) && errno != 0)
    return -1;
  return 0;

#else 

  /* We have nothing to go on.  Return -1.  */
  *user_sec = *system_sec = 0;
  *user_usec = *system_usec = 0;
  errno = ENOSYS;
  return -1;

#endif
}

#endif


/* POSIX states that CLOCK_REALTIME must be present if clock_gettime
   is available, others are optional.  */
#ifdef CLOCK_REALTIME
#define GF_CLOCK_REALTIME CLOCK_REALTIME
#else
#define GF_CLOCK_REALTIME 0
#endif

#ifdef CLOCK_MONOTONIC
#define GF_CLOCK_MONOTONIC CLOCK_MONOTONIC
#else
#define GF_CLOCK_MONOTONIC GF_CLOCK_REALTIME
#endif

/* Weakref trickery for clock_gettime().  On Glibc, clock_gettime()
   requires us to link in librt, which also pulls in libpthread.  In
   order to avoid this by default, only call clock_gettime() through a
   weak reference.  */
#ifdef HAVE_CLOCK_GETTIME
#ifdef SUPPORTS_WEAK
static int weak_gettime (clockid_t, struct timespec *) 
  __attribute__((__weakref__("clock_gettime")));
#else
static inline int weak_gettime (clockid_t clk_id, struct timespec *res)
{
  return clock_gettime (clk_id, res);
}
#endif
#endif

/* Arguments:
   clock_id - INPUT, must be either GF_CLOCK_REALTIME or GF_CLOCK_MONOTONIC
   secs     - OUTPUT, seconds
   nanosecs - OUTPUT, OPTIONAL, nanoseconds

   If clock_id equals GF_CLOCK_REALTIME, the OUTPUT arguments shall be
   the number of seconds and nanoseconds since the Epoch. If clock_id
   equals GF_CLOCK_MONOTONIC, and if the target supports it, the
   OUTPUT arguments represent a monotonically incrementing clock
   starting from some unspecified time in the past.

   Return value: 0 for success, -1 for error. In case of error, errno
   is set.
*/
static inline int
gf_gettime (int clock_id __attribute__((unused)), time_t * secs, 
            long * nanosecs)
{
#ifdef HAVE_CLOCK_GETTIME
  if (weak_gettime)
    {
      struct timespec ts;
      int err;
      err = weak_gettime (clock_id, &ts);
      *secs = ts.tv_sec;
      if (nanosecs)
	*nanosecs = ts.tv_nsec;
      return err;
    }
#endif
#ifdef HAVE_GETTIMEOFDAY
  struct timeval tv;
  int err;
  err = gettimeofday (&tv, NULL);
  *secs = tv.tv_sec;
  if (nanosecs)
    *nanosecs = tv.tv_usec * 1000;
  return err;
#elif HAVE_TIME
  time_t t, t2;
  t = time (&t2);
  *secs = t2;
  if (nanosecs)
    *nanosecs = 0;
  if (t == ((time_t)-1))
    return -1;
  return 0;
#else
  *secs = 0;
  if (nanosecs)
    *nanosecs = 0;
  errno = ENOSYS;
  return -1;
#endif
}


#endif /* LIBGFORTRAN_TIME_H */