my_getsystime.c

/* Copyright (c) 2004, 2011, Oracle and/or its affiliates. All rights reserved.

   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; version 2 of the License.

   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, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA */

/* get time since epoc in 100 nanosec units */
/* thus to get the current time we should use the system function
   with the highest possible resolution */

/* 
   TODO: in functions my_micro_time() and my_micro_time_and_time() there
   exists some common code that should be merged into a function.
*/

#include "mysys_priv.h"
#include "my_static.h"

ulonglong my_getsystime()
{
#ifdef HAVE_CLOCK_GETTIME
  struct timespec tp;
  clock_gettime(CLOCK_REALTIME, &tp);
  return (ulonglong)tp.tv_sec*10000000+(ulonglong)tp.tv_nsec/100;
#elif defined(_WIN32)
  LARGE_INTEGER t_cnt;
  if (query_performance_frequency)
  {
    QueryPerformanceCounter(&t_cnt);
    return ((t_cnt.QuadPart / query_performance_frequency * 10000000) +
            ((t_cnt.QuadPart % query_performance_frequency) * 10000000 /
             query_performance_frequency) + query_performance_offset);
  }
  return 0;
#else
  /* TODO: check for other possibilities for hi-res timestamping */
  struct timeval tv;
  gettimeofday(&tv,NULL);
  return (ulonglong)tv.tv_sec*10000000+(ulonglong)tv.tv_usec*10;
#endif
}


time_t my_time(myf flags)
{
  time_t t;
  /* The following loop is here beacuse time() may fail on some systems */
  while ((t= time(0)) == (time_t) -1)
  {
    if (flags & MY_WME)
      fprintf(stderr, "%s: Warning: time() call failed\n", my_progname);
  }
  return t;
}


#define OFFSET_TO_EPOCH 116444736000000000ULL

ulonglong my_micro_time()
{
#ifdef _WIN32
  ulonglong newtime;
  GetSystemTimeAsFileTime((FILETIME*)&newtime);
  newtime-= OFFSET_TO_EPOCH;
  return (newtime/10);
#else
  ulonglong newtime;
  struct timeval t;
  /*
    The following loop is here because gettimeofday may fail on some systems
  */
  while (gettimeofday(&t, NULL) != 0)
  {}
  newtime= (ulonglong)t.tv_sec * 1000000 + t.tv_usec;
  return newtime;
#endif
}


/* Difference between GetSystemTimeAsFileTime() and now() */

ulonglong my_micro_time_and_time(time_t *time_arg)
{
#ifdef _WIN32
  ulonglong newtime;
  GetSystemTimeAsFileTime((FILETIME*)&newtime);
  *time_arg= (time_t) ((newtime - OFFSET_TO_EPOCH) / 10000000);
  return (newtime/10);
#else
  ulonglong newtime;
  struct timeval t;
  /*
    The following loop is here because gettimeofday may fail on some systems
  */
  while (gettimeofday(&t, NULL) != 0)
  {}
  *time_arg= t.tv_sec;
  newtime= (ulonglong)t.tv_sec * 1000000 + t.tv_usec;
  return newtime;
#endif
}


time_t my_time_possible_from_micro(ulonglong microtime __attribute__((unused)))
{
#ifdef _WIN32
  time_t t;
  while ((t= time(0)) == (time_t) -1)
  {}
  return t;
#else
  return (time_t) (microtime / 1000000);
#endif
}