/* gettimeofday.c - Don Yang (uguu.org)

   10/02/06
                                                                           */

#include<stdio.h>
#include<stdlib.h>
#include"gettimeofday.h"
#pragma warning(disable:4100)

#ifdef USE_QUERY_PERFORMANCE_COUNTER

static LARGE_INTEGER ClockFrequency = { 0LL };

/* Emulate gettimeofday using QueryPerformanceFrequency.
   This version appears to be unstable on multiprocessor or variable
   clock rate machines.                                              */
int gettimeofday(/*@out@*//*@null@*/struct timeval *tv,
                 /*@unused@*//*@null@*/void *tz)
{
   LARGE_INTEGER current_time;

   if( ClockFrequency.QuadPart == 0LL )
   {
      if( !QueryPerformanceFrequency(&ClockFrequency) )
      {
         (void)puts("High resolution clock not supported!");
         exit(EXIT_FAILURE);
      }
      if( ClockFrequency.QuadPart == 0LL )
      {
         (void)puts("High resolution clock not supported!");
         exit(EXIT_FAILURE);
      }
   }

   if( !QueryPerformanceCounter(&current_time) )
   {
      (void)puts("Error querying counters!");
      exit(EXIT_FAILURE);
   }

   current_time.QuadPart =
      (1000000ULL * current_time.QuadPart) / ClockFrequency.QuadPart;
   tv->tv_sec = (long)(current_time.QuadPart / 1000000ULL);
   tv->tv_usec = (long)(current_time.QuadPart % 1000000ULL);

   return 0;
}

#else

/* timeGetTime is less accurate, and introduces dependency on
   winmm.lib (which GLUT already uses anyways), but seems generally
   more reliable.                                                   */
int gettimeofday(/*@out@*//*@null@*/struct timeval *tv,
                 /*@unused@*//*@null@*/void *tz)
{
   DWORD t = timeGetTime();
   tv->tv_sec = t / 1000;
   tv->tv_usec = (t % 1000) * 1000;
   return 0;
}

#endif