/*

Simple DirectMedia Layer

Copyright (C) 1997-2013 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

*/

/* Reworked monotonic clock to not assume the current system has one

as not all linux kernels provide a monotonic clock (yeah recent ones

probably do)

Also added OS X Monotonic clock support

Based on work in https://github.com/ThomasHabets/monotonic_clock

*/

#if HAVE_NANOSLEEP || HAVE_CLOCK_GETTIME

#include <time.h>

#endif

#ifdef __APPLE__

#include <mach/mach_time.h>

#endif

/* The first ticks value of the application */

#if HAVE_CLOCK_GETTIME

static struct timespec start_ts;

#elif defined(__APPLE__)

static uint64_t start_mach;

mach_timebase_info_data_t mach_base_info;

#endif

static SDL_bool has_monotonic_time = SDL_FALSE;

static struct timeval start_tv;

static SDL_bool ticks_started = SDL_FALSE;

void

SDL_InitTicks(void)

{

if (ticks_started) {

return;

}

ticks_started = SDL_TRUE;

/* Set first ticks value */

#if HAVE_CLOCK_GETTIME

if (clock_gettime(CLOCK_MONOTONIC, &start_ts) == 0) {

has_monotonic_time = SDL_TRUE;

} else

#elif defined(__APPLE__)

kern_return_t ret = mach_timebase_info(&mach_base_info);

if (ret == 0) {

has_monotonic_time = SDL_TRUE;

start_mach = mach_absolute_time();

} else

#endif

{

gettimeofday(&start_tv, NULL);

}

}

Uint32

SDL_GetTicks(void)

{

Uint32 ticks;

if (!ticks_started) {

SDL_InitTicks();

}

if (has_monotonic_time) {

#if HAVE_CLOCK_GETTIME

struct timespec now;

clock_gettime(CLOCK_MONOTONIC, &now);

ticks = (now.tv_sec - start_ts.tv_sec) * 1000 + (now.tv_nsec -

start_ts.tv_nsec) / 1000000;

#elif defined(__APPLE__)

uint64_t now = mach_absolute_time();

ticks = (((now - start_mach) * mach_base_info.numer) / mach_base_info.denom) / 1000000;

#endif

} else {

struct timeval now;

gettimeofday(&now, NULL);

ticks =

(now.tv_sec - start_tv.tv_sec) * 1000 + (now.tv_usec -

start_tv.tv_usec) / 1000;

}

return (ticks);

}

Uint64

SDL_GetPerformanceCounter(void)

{

Uint64 ticks;

if (!ticks_started) {

SDL_InitTicks();

}

if (has_monotonic_time) {

#if HAVE_CLOCK_GETTIME

struct timespec now;

clock_gettime(CLOCK_MONOTONIC, &now);

ticks = now.tv_sec;

ticks *= 1000000000;

ticks += now.tv_nsec;

#elif defined(__APPLE__)

ticks = mach_absolute_time();

#endif

} else {

struct timeval now;

gettimeofday(&now, NULL);

ticks = now.tv_sec;

ticks *= 1000000;

ticks += now.tv_usec;

}

return (ticks);

}

Uint64

SDL_GetPerformanceFrequency(void)

{

if (!ticks_started) {

SDL_InitTicks();

}

if (has_monotonic_time) {

#if HAVE_CLOCK_GETTIME

return 1000000000;

#elif defined(__APPLE__)

Uint64 freq = mach_base_info.denom;

freq *= 1000000000;

freq /= mach_base_info.numer;

return freq;

#endif

}

return 1000000;

}

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: */