/* * Precise timer routines using Mach timing * * Copyright (c) 2003-2004, Dan Villiom Podlaski Christiansen * * Permission is hereby granted, free of charge, to any person * obtaining a copy of this software and associated documentation * files (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, copy, * modify, merge, publish, distribute, sublicense, and/or sell copies * of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. */#include <mplaylib.h>#include <mplaylib.h>#include <time.h>#include <math.h>#include <sys/time.h>#include <mach/mach_time.h>#include "config.h"#include "mp_msg.h"#include "timer.h"/* global variables */static double relative_time, startup_time;static double timebase_ratio;const char *timer_name = "Darwin accurate";/* the core sleep function, uses floats and is used in MPlayer G2 */float sleep_accurate(float time_frame){	uint64_t deadline = time_frame / timebase_ratio + mach_absolute_time();		mach_wait_until(deadline);		return (mach_absolute_time() - deadline) * timebase_ratio;}/* wrapper for MPlayer G1 */int usec_sleep(int usec_delay){  return sleep_accurate(usec_delay / 1e6) * 1e6;}/* current time in microseconds */unsigned int GetTimer(){  return (unsigned int)((mach_absolute_time() * timebase_ratio - startup_time)			* 1e6);}/* current time in milliseconds */unsigned int GetTimerMS(){  return (unsigned int)(GetTimer() / 1000);}/* time spent between now and last call in seconds */float GetRelativeTime(){  double last_time = relative_time;    if (!relative_time)    InitTimer();    relative_time = mach_absolute_time() * timebase_ratio;  return (float)(relative_time-last_time);}/* initialize timer, must be called at least once at start */void InitTimer(){  struct mach_timebase_info timebase;  mach_timebase_info(&timebase);  timebase_ratio = (double)timebase.numer / (double)timebase.denom     * (double)1e-9;      relative_time = startup_time =     (double)(mach_absolute_time() * timebase_ratio);}#if 0#include <mplaylib.h>int main() {  int i,j, r, c = 200;  long long t = 0;    InitTimer();  for (i = 0; i < c; i++) {    const int delay = rand() / (RAND_MAX / 1e5);    j = GetTimer();#if 1    r = usec_sleep(delay);#else    r = sleep_accurate(delay / 1e6) * 1e6;#endif    j = (GetTimer() - j) - delay;    printf("sleep time:%8i %5i (%i)\n", delay, j, j - r);    t += j - r;  }  fprintf(stderr, "average error:\t%lli\n", t / c);  return 0;}#endif