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SDL_systimer.c
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SDL_systimer.c
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/*
Simple DirectMedia Layer
Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_config.h"
#ifdef SDL_TIMER_UNIX
#include <stdio.h>
#include <sys/time.h>
#include <unistd.h>
#include <errno.h>
#include "SDL_timer.h"
/* The clock_gettime provides monotonous time, so we should use it if
it's available. The clock_gettime function is behind ifdef
for __USE_POSIX199309
Tommi Kyntola (tommi.kyntola@ray.fi) 27/09/2005
*/
#if HAVE_NANOSLEEP || HAVE_CLOCK_GETTIME
#include <time.h>
#endif
/* The first ticks value of the application */
#ifdef HAVE_CLOCK_GETTIME
static struct timespec start;
#else
static struct timeval start;
#endif /* HAVE_CLOCK_GETTIME */
void
SDL_StartTicks(void)
{
/* Set first ticks value */
#if HAVE_CLOCK_GETTIME
clock_gettime(CLOCK_MONOTONIC, &start);
#else
gettimeofday(&start, NULL);
#endif
}
Uint32
SDL_GetTicks(void)
{
#if HAVE_CLOCK_GETTIME
Uint32 ticks;
struct timespec now;
clock_gettime(CLOCK_MONOTONIC, &now);
ticks =
(now.tv_sec - start.tv_sec) * 1000 + (now.tv_nsec -
start.tv_nsec) / 1000000;
return (ticks);
#else
Uint32 ticks;
struct timeval now;
gettimeofday(&now, NULL);
ticks =
(now.tv_sec - start.tv_sec) * 1000 + (now.tv_usec -
start.tv_usec) / 1000;
return (ticks);
#endif
}
Uint64
SDL_GetPerformanceCounter(void)
{
#if HAVE_CLOCK_GETTIME
Uint64 ticks;
struct timespec now;
clock_gettime(CLOCK_MONOTONIC, &now);
ticks = now.tv_sec;
ticks *= 1000000000;
ticks += now.tv_nsec;
return (ticks);
#else
Uint64 ticks;
struct timeval now;
gettimeofday(&now, NULL);
ticks = now.tv_sec;
ticks *= 1000000;
ticks += now.tv_usec;
return (ticks);
#endif
}
Uint64
SDL_GetPerformanceFrequency(void)
{
#if HAVE_CLOCK_GETTIME
return 1000000000;
#else
return 1000000;
#endif
}
void
SDL_Delay(Uint32 ms)
{
int was_error;
#if HAVE_NANOSLEEP
struct timespec elapsed, tv;
#else
struct timeval tv;
Uint32 then, now, elapsed;
#endif
/* Set the timeout interval */
#if HAVE_NANOSLEEP
elapsed.tv_sec = ms / 1000;
elapsed.tv_nsec = (ms % 1000) * 1000000;
#else
then = SDL_GetTicks();
#endif
do {
errno = 0;
#if HAVE_NANOSLEEP
tv.tv_sec = elapsed.tv_sec;
tv.tv_nsec = elapsed.tv_nsec;
was_error = nanosleep(&tv, &elapsed);
#else
/* Calculate the time interval left (in case of interrupt) */
now = SDL_GetTicks();
elapsed = (now - then);
then = now;
if (elapsed >= ms) {
break;
}
ms -= elapsed;
tv.tv_sec = ms / 1000;
tv.tv_usec = (ms % 1000) * 1000;
was_error = select(0, NULL, NULL, NULL, &tv);
#endif /* HAVE_NANOSLEEP */
} while (was_error && (errno == EINTR));
}
#endif /* SDL_TIMER_UNIX */
/* vi: set ts=4 sw=4 expandtab: */