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SDL_systimer.c
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2011 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library 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
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Sam Lantinga
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slouken@libsdl.org
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*/
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#include "SDL_config.h"
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#ifdef SDL_TIMER_UNIX
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#include <stdio.h>
#include <sys/time.h>
#include <unistd.h>
#include <errno.h>
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#include "SDL_timer.h"
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/* 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
*/
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#if HAVE_NANOSLEEP || HAVE_CLOCK_GETTIME
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#include <time.h>
#endif
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/* The first ticks value of the application */
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#ifdef HAVE_CLOCK_GETTIME
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static struct timespec start;
#else
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static struct timeval start;
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#endif /* HAVE_CLOCK_GETTIME */
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void
SDL_StartTicks(void)
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/* Set first ticks value */
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#if HAVE_CLOCK_GETTIME
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clock_gettime(CLOCK_MONOTONIC, &start);
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gettimeofday(&start, NULL);
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}
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Uint32
SDL_GetTicks(void)
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#if HAVE_CLOCK_GETTIME
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Uint32 ticks;
struct timespec now;
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clock_gettime(CLOCK_MONOTONIC, &now);
ticks =
(now.tv_sec - start.tv_sec) * 1000 + (now.tv_nsec -
start.tv_nsec) / 1000000;
return (ticks);
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Uint32 ticks;
struct timeval now;
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gettimeofday(&now, NULL);
ticks =
(now.tv_sec - start.tv_sec) * 1000 + (now.tv_usec -
start.tv_usec) / 1000;
return (ticks);
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#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;
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}
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void
SDL_Delay(Uint32 ms)
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{
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int was_error;
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#if HAVE_NANOSLEEP
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struct timespec elapsed, tv;
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#else
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struct timeval tv;
Uint32 then, now, elapsed;
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#endif
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/* Set the timeout interval */
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#if HAVE_NANOSLEEP
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elapsed.tv_sec = ms / 1000;
elapsed.tv_nsec = (ms % 1000) * 1000000;
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#else
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then = SDL_GetTicks();
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#endif
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do {
errno = 0;
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#if HAVE_NANOSLEEP
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tv.tv_sec = elapsed.tv_sec;
tv.tv_nsec = elapsed.tv_nsec;
was_error = nanosleep(&tv, &elapsed);
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#else
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/* 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);
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#endif /* HAVE_NANOSLEEP */
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} while (was_error && (errno == EINTR));
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}
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#endif /* SDL_TIMER_UNIX */
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/* vi: set ts=4 sw=4 expandtab: */