/*+
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    SDL - Simple DirectMedia Layer+
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    Copyright (C) 1997-2006 Sam Lantinga+
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+
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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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+
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    This library is distributed in the hope that it will be useful,+
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    but WITHOUT ANY WARRANTY; without even the implied warranty of+
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    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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+
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    You should have received a copy of the GNU Lesser General Public+
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    License along with this library; if not, write to the Free Software+
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    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA+
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+
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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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+
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/* RISC OS semiphores based on linux code */+
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+
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+
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#include "SDL_timer.h"+
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#include "SDL_thread.h"+
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#include "SDL_systhread_c.h"+
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+
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#if !SDL_THREADS_DISABLED+
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+
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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");+
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	return (SDL_sem *)0;+
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}+
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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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+
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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");+
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	return -1;+
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}+
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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");+
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	return -1;+
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}+
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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");+
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	return -1;+
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}+
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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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+
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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");+
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	return -1;+
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}+
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+
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#else+
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+
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+
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#include <unistd.h>			/* For getpid() */+
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#include <pthread.h>+
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#include <semaphore.h>+
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+
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struct SDL_semaphore {+
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	sem_t *sem;+
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	sem_t sem_data;+
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};+
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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));+
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	if ( sem ) {+
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		if ( sem_init(&sem->sem_data, 0, initial_value) < 0 ) {+
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			SDL_SetError("sem_init() failed");+
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			SDL_free(sem);+
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			sem = NULL;+
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		} else {+
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			sem->sem = &sem->sem_data;+
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		}+
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	} else {+
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		SDL_OutOfMemory();+
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	}+
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	return sem;+
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}+
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+
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void SDL_DestroySemaphore(SDL_sem *sem)+
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{+
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	if ( sem ) {+
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		sem_destroy(sem->sem);+
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		SDL_free(sem);+
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	}+
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}+
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+
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int SDL_SemTryWait(SDL_sem *sem)+
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{+
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	int retval;+
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+
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	if ( ! sem ) {+
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		SDL_SetError("Passed a NULL semaphore");+
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		return -1;+
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	}+
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	retval = SDL_MUTEX_TIMEDOUT;+
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	if ( sem_trywait(sem->sem) == 0 ) {+
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		retval = 0;+
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	}+
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	return retval;+
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}+
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+
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int SDL_SemWait(SDL_sem *sem)+
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{+
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	int retval;+
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+
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	if ( ! sem ) {+
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		SDL_SetError("Passed a NULL semaphore");+
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		return -1;+
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	}+
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+
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	retval = sem_wait(sem->sem);+
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	if ( retval < 0 ) {+
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		SDL_SetError("sem_wait() failed");+
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	}+
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	return retval;+
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}+
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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;+
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+
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	if ( ! sem ) {+
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		SDL_SetError("Passed a NULL semaphore");+
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		return -1;+
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	}+
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+
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	/* Try the easy cases first */+
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	if ( timeout == 0 ) {+
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		return SDL_SemTryWait(sem);+
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	}+
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	if ( timeout == SDL_MUTEX_MAXWAIT ) {+
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		return SDL_SemWait(sem);+
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	}+
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+
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	/* Ack!  We have to busy wait... */+
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	timeout += SDL_GetTicks();+
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	do {+
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		retval = SDL_SemTryWait(sem);+
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		if ( retval == 0 ) {+
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			break;+
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		}+
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		SDL_Delay(1);+
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	} while ( SDL_GetTicks() < timeout );+
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+
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	return retval;+
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}+
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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;+
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	if ( sem ) {+
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		sem_getvalue(sem->sem, &ret);+
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		if ( ret < 0 ) {+
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			ret = 0;+
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		}+
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	}+
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	return (Uint32)ret;+
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}+
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+
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int SDL_SemPost(SDL_sem *sem)+
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{+
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	int retval;+
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+
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	if ( ! sem ) {+
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		SDL_SetError("Passed a NULL semaphore");+
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		return -1;+
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	}+
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+
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	retval = sem_post(sem->sem);+
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	if ( retval < 0 ) {+
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		SDL_SetError("sem_post() failed");+
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	}+
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	return retval;+
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}+
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+
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#endif /* !SDL_THREADS_DISABLED */+
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