/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 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"

/* An implementation of semaphores using mutexes and condition variables */

#include "SDL_thread.h"
#include "SDL_systhread_c.h"


struct SDL_semaphore
{
    struct SignalSemaphore Sem;
};

#undef D

#define D(x)

SDL_sem *
SDL_CreateSemaphore (Uint32 initial_value)
{
    SDL_sem *sem;

    sem = (SDL_sem *) SDL_malloc (sizeof (*sem));

    if (!sem) {
        SDL_OutOfMemory ();
        return (0);
    }

    D (bug ("Creating semaphore %lx...\n", sem));

    SDL_memset (sem, 0, sizeof (*sem));

    InitSemaphore (&sem->Sem);

    return (sem);
}

void
SDL_DestroySemaphore (SDL_sem * sem)
{
    D (bug ("Destroying semaphore %lx...\n", sem));

    if (sem) {
// Condizioni per liberare i task in attesa?
        SDL_free (sem);
    }
}

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

    D (bug ("TryWait semaphore...%lx\n", sem));

    ObtainSemaphore (&sem->Sem);
//      ReleaseSemaphore(&sem->Sem);

    return 1;
}

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


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

    D (bug ("WaitTimeout (%ld) semaphore...%lx\n", timeout, sem));

    /* A timeout of 0 is an easy case */
    if (timeout == 0) {
        ObtainSemaphore (&sem->Sem);
        return 1;
    }
    if (!(retval = AttemptSemaphore (&sem->Sem))) {
        SDL_Delay (timeout);
        retval = AttemptSemaphore (&sem->Sem);
    }

    if (retval == TRUE) {
//              ReleaseSemaphore(&sem->Sem);
        retval = 1;
    }

    return retval;
}

int
SDL_SemWait (SDL_sem * sem)
{
    ObtainSemaphore (&sem->Sem);
    return 0;
}

Uint32
SDL_SemValue (SDL_sem * sem)
{
    Uint32 value;

    value = 0;
    if (sem) {
#ifdef STORMC4_WOS
        value = sem->Sem.ssppc_SS.ss_NestCount;
#else
        value = sem->Sem.ss_NestCount;
#endif
    }
    return value;
}

int
SDL_SemPost (SDL_sem * sem)
{
    if (!sem) {
        SDL_SetError ("Passed a NULL semaphore");
        return -1;
    }
    D (bug ("SemPost semaphore...%lx\n", sem));

    ReleaseSemaphore (&sem->Sem);
    return 0;
}

/* vi: set ts=4 sw=4 expandtab: */