mirror of https://github.com/mpv-player/mpv
120 lines
2.8 KiB
C
120 lines
2.8 KiB
C
/*
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* Precise timer routines using Mach timing
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*
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* Copyright (c) 2003-2004, Dan Villiom Podlaski Christiansen
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy,
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* modify, merge, publish, distribute, sublicense, and/or sell copies
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* of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*/
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#include <unistd.h>
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#include <stdlib.h>
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#include <time.h>
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#include <math.h>
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#include <sys/time.h>
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#include <mach/mach_time.h>
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#include "config.h"
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#include "mp_msg.h"
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#include "timer.h"
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/* global variables */
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static double relative_time, startup_time;
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static double timebase_ratio;
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const char *timer_name = "Darwin accurate";
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/* the core sleep function, uses floats and is used in MPlayer G2 */
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float sleep_accurate(float time_frame)
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{
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uint64_t deadline = time_frame / timebase_ratio + mach_absolute_time();
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mach_wait_until(deadline);
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return (mach_absolute_time() - deadline) * timebase_ratio;
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}
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/* wrapper for MPlayer G1 */
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int usec_sleep(int usec_delay)
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{
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return sleep_accurate(usec_delay / 1e6) * 1e6;
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}
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/* current time in microseconds */
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unsigned int GetTimer()
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{
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return (unsigned int)((mach_absolute_time() * timebase_ratio - startup_time)
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* 1e6);
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}
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/* current time in milliseconds */
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unsigned int GetTimerMS()
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{
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return (unsigned int)((mach_absolute_time() * timebase_ratio - startup_time)
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* 1e3);
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}
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/* time spent between now and last call in seconds */
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float GetRelativeTime()
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{
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double last_time = relative_time;
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if (!relative_time)
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InitTimer();
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relative_time = mach_absolute_time() * timebase_ratio;
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return (float)(relative_time-last_time);
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}
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/* initialize timer, must be called at least once at start */
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void InitTimer()
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{
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struct mach_timebase_info timebase;
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mach_timebase_info(&timebase);
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timebase_ratio = (double)timebase.numer / (double)timebase.denom
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* (double)1e-9;
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relative_time = startup_time =
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(double)(mach_absolute_time() * timebase_ratio);
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}
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#if 0
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#include <stdio.h>
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int main(void) {
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int i,j, r, c = 200;
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long long t = 0;
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InitTimer();
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for (i = 0; i < c; i++) {
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const int delay = rand() / (RAND_MAX / 1e5);
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j = GetTimer();
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#if 1
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r = usec_sleep(delay);
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#else
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r = sleep_accurate(delay / 1e6) * 1e6;
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#endif
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j = (GetTimer() - j) - delay;
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printf("sleep time:%8i %5i (%i)\n", delay, j, j - r);
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t += j - r;
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}
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fprintf(stderr, "average error:\t%lli\n", t / c);
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return 0;
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}
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#endif
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