view src/thread/win32/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 6f3308d4b6cd
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"

/* Semaphore functions using the Win32 API */

#define WIN32_LEAN_AND_MEAN
#include <windows.h>

#include "SDL_thread.h"
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
#include "win_ce_semaphore.h"
#endif


struct SDL_semaphore
{
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
    SYNCHHANDLE id;
#else
    HANDLE id;
#endif
    Uint32 volatile count;
};


/* Create a semaphore */
SDL_sem *
SDL_CreateSemaphore(Uint32 initial_value)
{
    SDL_sem *sem;

    /* Allocate sem memory */
    sem = (SDL_sem *) SDL_malloc(sizeof(*sem));
    if (sem) {
        /* Create the semaphore, with max value 32K */
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
        sem->id = CreateSemaphoreCE(NULL, initial_value, 32 * 1024, NULL);
#else
        sem->id = CreateSemaphore(NULL, initial_value, 32 * 1024, NULL);
#endif
        sem->count = initial_value;
        if (!sem->id) {
            SDL_SetError("Couldn't create semaphore");
            SDL_free(sem);
            sem = NULL;
        }
    } else {
        SDL_OutOfMemory();
    }
    return (sem);
}

/* Free the semaphore */
void
SDL_DestroySemaphore(SDL_sem * sem)
{
    if (sem) {
        if (sem->id) {
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
            CloseSynchHandle(sem->id);
#else
            CloseHandle(sem->id);
#endif
            sem->id = 0;
        }
        SDL_free(sem);
    }
}

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

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

    if (timeout == SDL_MUTEX_MAXWAIT) {
        dwMilliseconds = INFINITE;
    } else {
        dwMilliseconds = (DWORD) timeout;
    }
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
    switch (WaitForSemaphoreCE(sem->id, dwMilliseconds)) {
#else
    switch (WaitForSingleObject(sem->id, dwMilliseconds)) {
#endif
    case WAIT_OBJECT_0:
        InterlockedDecrement(&sem->count);
        retval = 0;
        break;
    case WAIT_TIMEOUT:
        retval = SDL_MUTEX_TIMEDOUT;
        break;
    default:
        SDL_SetError("WaitForSingleObject() failed");
        retval = -1;
        break;
    }
    return retval;
}

int
SDL_SemTryWait(SDL_sem * sem)
{
    return SDL_SemWaitTimeout(sem, 0);
}

int
SDL_SemWait(SDL_sem * sem)
{
    return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT);
}

/* Returns the current count of the semaphore */
Uint32
SDL_SemValue(SDL_sem * sem)
{
    if (!sem) {
        SDL_SetError("Passed a NULL sem");
        return 0;
    }
    return sem->count;
}

int
SDL_SemPost(SDL_sem * sem)
{
    if (!sem) {
        SDL_SetError("Passed a NULL sem");
        return -1;
    }
    /* Increase the counter in the first place, because
     * after a successful release the semaphore may
     * immediately get destroyed by another thread which
     * is waiting for this semaphore.
     */
    InterlockedIncrement(&sem->count);
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
    if (ReleaseSemaphoreCE(sem->id, 1, NULL) == FALSE) {
#else
    if (ReleaseSemaphore(sem->id, 1, NULL) == FALSE) {
#endif
        InterlockedDecrement(&sem->count);      /* restore */
        SDL_SetError("ReleaseSemaphore() failed");
        return -1;
    }
    return 0;
}

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