view src/thread/irix/SDL_syssem.c @ 3468:789b97008d8a

My first OpenGL shader! Momma will be so proud! This shader implements the software renderer mask semantics where the source pixel is multiplied by the color and alpha modulation values and then any pixel with non-zero alpha is fully opaque. The OpenGL renderer on Mac OS X now passes all the automated render tests! :)
author Sam Lantinga <slouken@libsdl.org>
date Sat, 21 Nov 2009 05:29:31 +0000
parents 99210400e8b9
children f7b03b6838cb
line wrap: on
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    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
    Lesser General Public License for more details.

    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

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

#include "SDL_thread.h"
#include "SDL_timer.h"


#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <errno.h>

#include "SDL_error.h"
#include "SDL_thread.h"


struct SDL_semaphore
{
    int id;
};

/* Not defined by many operating systems, use configure to detect */
/*
#if !defined(HAVE_SEMUN)
union semun {
	int val;
	struct semid_ds *buf;
	ushort *array;
};
#endif
*/

static struct sembuf op_trywait[2] = {
    {0, -1, (IPC_NOWAIT | SEM_UNDO)}    /* Decrement semaphore, no block */
};

static struct sembuf op_wait[2] = {
    {0, -1, SEM_UNDO}           /* Decrement semaphore */
};

static struct sembuf op_post[1] = {
    {0, 1, (IPC_NOWAIT | SEM_UNDO)}     /* Increment semaphore */
};

/* Create a blockable semaphore */
SDL_sem *
SDL_CreateSemaphore(Uint32 initial_value)
{
    extern int _creating_thread_lock;   /* SDL_threads.c */
    SDL_sem *sem;
    union semun init;

    sem = (SDL_sem *) SDL_malloc(sizeof(*sem));
    if (sem == NULL) {
        SDL_OutOfMemory();
        return (NULL);
    }
    sem->id = semget(IPC_PRIVATE, 1, (0600 | IPC_CREAT));
    if (sem->id < 0) {
        SDL_SetError("Couldn't create semaphore");
        SDL_free(sem);
        return (NULL);
    }
    init.val = initial_value;   /* Initialize semaphore */
    semctl(sem->id, 0, SETVAL, init);
    return (sem);
}

void
SDL_DestroySemaphore(SDL_sem * sem)
{
    if (sem) {
#ifdef __IRIX__
        semctl(sem->id, 0, IPC_RMID);
#else
        union semun dummy;
        dummy.val = 0;
        semctl(sem->id, 0, IPC_RMID, dummy);
#endif
        SDL_free(sem);
    }
}

int
SDL_SemTryWait(SDL_sem * sem)
{
    int retval;

    if (!sem) {
        SDL_SetError("Passed a NULL semaphore");
        return -1;
    }

    retval = 0;
  tryagain:
    if (semop(sem->id, op_trywait, 1) < 0) {
        if (errno == EINTR) {
            goto tryagain;
        }
        retval = SDL_MUTEX_TIMEDOUT;
    }
    return retval;
}

int
SDL_SemWait(SDL_sem * sem)
{
    int retval;

    if (!sem) {
        SDL_SetError("Passed a NULL semaphore");
        return -1;
    }

    retval = 0;
  tryagain:
    if (semop(sem->id, op_wait, 1) < 0) {
        if (errno == EINTR) {
            goto tryagain;
        }
        SDL_SetError("Semaphore operation error");
        retval = -1;
    }
    return retval;
}

int
SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout)
{
    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;
}

Uint32
SDL_SemValue(SDL_sem * sem)
{
    int semval;
    Uint32 value;

    value = 0;
    if (sem) {
      tryagain:
#ifdef __IRIX__
        semval = semctl(sem->id, 0, GETVAL);
#else
        {
            union semun arg;
            arg.val = 0;
            semval = semctl(sem->id, 0, GETVAL, arg);
        }
#endif
        if (semval < 0) {
            if (errno == EINTR) {
                goto tryagain;
            }
        } else {
            value = (Uint32) semval;
        }
    }
    return value;
}

int
SDL_SemPost(SDL_sem * sem)
{
    int retval;

    if (!sem) {
        SDL_SetError("Passed a NULL semaphore");
        return -1;
    }

    retval = 0;
  tryagain:
    if (semop(sem->id, op_post, 1) < 0) {
        if (errno == EINTR) {
            goto tryagain;
        }
        SDL_SetError("Semaphore operation error");
        retval = -1;
    }
    return retval;
}

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