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SDL_syssem.c
217 lines (181 loc) · 4.14 KB
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2006 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
slouken@libsdl.org
*/
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#include "SDL_config.h"
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/* RISC OS semiphores based on linux code */
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#include "SDL_timer.h"
#include "SDL_thread.h"
#include "SDL_systhread_c.h"
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#if !SDL_THREADS_DISABLED
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SDL_sem *
SDL_CreateSemaphore (Uint32 initial_value)
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{
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SDL_SetError ("SDL not configured with thread support");
return (SDL_sem *) 0;
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}
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void
SDL_DestroySemaphore (SDL_sem * sem)
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{
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return;
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}
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int
SDL_SemTryWait (SDL_sem * sem)
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{
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SDL_SetError ("SDL not configured with thread support");
return -1;
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}
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int
SDL_SemWaitTimeout (SDL_sem * sem, Uint32 timeout)
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{
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SDL_SetError ("SDL not configured with thread support");
return -1;
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}
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int
SDL_SemWait (SDL_sem * sem)
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{
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SDL_SetError ("SDL not configured with thread support");
return -1;
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}
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Uint32
SDL_SemValue (SDL_sem * sem)
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{
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return 0;
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}
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int
SDL_SemPost (SDL_sem * sem)
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{
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SDL_SetError ("SDL not configured with thread support");
return -1;
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}
#else
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#include <unistd.h> /* For getpid() */
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#include <pthread.h>
#include <semaphore.h>
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struct SDL_semaphore
{
sem_t *sem;
sem_t sem_data;
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};
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/* Create a semaphore, initialized with value */
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SDL_sem *
SDL_CreateSemaphore (Uint32 initial_value)
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{
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SDL_sem *sem = (SDL_sem *) SDL_malloc (sizeof (SDL_sem));
if (sem) {
if (sem_init (&sem->sem_data, 0, initial_value) < 0) {
SDL_SetError ("sem_init() failed");
SDL_free (sem);
sem = NULL;
} else {
sem->sem = &sem->sem_data;
}
} else {
SDL_OutOfMemory ();
}
return sem;
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}
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void
SDL_DestroySemaphore (SDL_sem * sem)
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{
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if (sem) {
sem_destroy (sem->sem);
SDL_free (sem);
}
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}
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int
SDL_SemTryWait (SDL_sem * sem)
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{
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int retval;
if (!sem) {
SDL_SetError ("Passed a NULL semaphore");
return -1;
}
retval = SDL_MUTEX_TIMEDOUT;
if (sem_trywait (sem->sem) == 0) {
retval = 0;
}
return retval;
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}
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int
SDL_SemWait (SDL_sem * sem)
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{
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int retval;
if (!sem) {
SDL_SetError ("Passed a NULL semaphore");
return -1;
}
retval = sem_wait (sem->sem);
if (retval < 0) {
SDL_SetError ("sem_wait() failed");
}
return retval;
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}
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int
SDL_SemWaitTimeout (SDL_sem * sem, Uint32 timeout)
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{
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int retval;
if (!sem) {
SDL_SetError ("Passed a NULL semaphore");
return -1;
}
/* Try the easy cases first */
if (timeout == 0) {
return SDL_SemTryWait (sem);
}
if (timeout == SDL_MUTEX_MAXWAIT) {
return SDL_SemWait (sem);
}
/* Ack! We have to busy wait... */
timeout += SDL_GetTicks ();
do {
retval = SDL_SemTryWait (sem);
if (retval == 0) {
break;
}
SDL_Delay (1);
}
while (SDL_GetTicks () < timeout);
return retval;
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}
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Uint32
SDL_SemValue (SDL_sem * sem)
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{
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int ret = 0;
if (sem) {
sem_getvalue (sem->sem, &ret);
if (ret < 0) {
ret = 0;
}
}
return (Uint32) ret;
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}
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int
SDL_SemPost (SDL_sem * sem)
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{
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int retval;
if (!sem) {
SDL_SetError ("Passed a NULL semaphore");
return -1;
}
retval = sem_post (sem->sem);
if (retval < 0) {
SDL_SetError ("sem_post() failed");
}
return retval;
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}
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#endif /* !SDL_THREADS_DISABLED */
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/* vi: set ts=4 sw=4 expandtab: */