view src/thread/dc/SDL_syscond.c @ 3168:6338b7f2d024

Hi, I have prepared a set of patches to readd WindowsCE support to SDL 1.3. I've created a new GAPI/Rawframebuffer and a DirectDraw renderer. Both renderers are work in progress and there are several unimplemented cases. (Notably RenderLine/RenderPoint/RenderFill/QueryTexturePixels/UpdateTexture and texture blending ) Nevertheless I am successfully using these renderers together with the SDL software renderer. (On most devices the SDL software renderer will be much faster as there are only badly optimized vendor drivers available) I send these patches now in this unpolished state because there seems to be some interest in win ce and someone has to start supporting SDL 1.3 Now on to the patches: wince_events_window_fixes.patch fixes some wince incompatibilities and adds fullscreen support via SHFullScreen. NOTE: This patch shouldn't have any side effects on Windows, but I have NOT tested it on Windows, so please double-check. This patch doesn't dependent on the following ones. wince_renderers_system.patch This patch does all necessary modifications to the SDL system. - it adds the renderers to the configure system - it adds the renderers to win32video SDL_ceddrawrender.c SDL_ceddrawrender.h SDL_gapirender_c.h SDL_gapirender.c SDL_gapirender.h these files add the new render drivers and should be placed in src/video/win32 Some notes to people who want to test this: - I have only compiled sdl with ming32ce, so the VisualC files are not up to date - As mingw32ce has no ddraw.h this file must be taken from the MS SDK and modified to work with gcc - I had to modify line 2611 in configure.in to EXTRA_LDFLAGS="$EXTRA_LDFLAGS -lcoredll -lcommctrl -lmmtimer -Wl,--image-base -Wl,0x10000" otherwise GetCPinfo wouldn't link. If someone knows whats causing this I'd be happy to hear about it. It would be great if these patches could make their way into SVN as this would make collaboration much much easier. I'm out of office for the next week and therefore will be unavailable via email. Regards Stefan
author Sam Lantinga <slouken@libsdl.org>
date Sun, 07 Jun 2009 02:44:46 +0000
parents 99210400e8b9
children
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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"

/* An implementation of condition variables using semaphores and mutexes */
/*
   This implementation borrows heavily from the BeOS condition variable
   implementation, written by Christopher Tate and Owen Smith.  Thanks!
 */

#include "SDL_thread.h"

struct SDL_cond
{
    SDL_mutex *lock;
    int waiting;
    int signals;
    SDL_sem *wait_sem;
    SDL_sem *wait_done;
};

/* Create a condition variable */
SDL_cond *
SDL_CreateCond(void)
{
    SDL_cond *cond;

    cond = (SDL_cond *) SDL_malloc(sizeof(SDL_cond));
    if (cond) {
        cond->lock = SDL_CreateMutex();
        cond->wait_sem = SDL_CreateSemaphore(0);
        cond->wait_done = SDL_CreateSemaphore(0);
        cond->waiting = cond->signals = 0;
        if (!cond->lock || !cond->wait_sem || !cond->wait_done) {
            SDL_DestroyCond(cond);
            cond = NULL;
        }
    } else {
        SDL_OutOfMemory();
    }
    return (cond);
}

/* Destroy a condition variable */
void
SDL_DestroyCond(SDL_cond * cond)
{
    if (cond) {
        if (cond->wait_sem) {
            SDL_DestroySemaphore(cond->wait_sem);
        }
        if (cond->wait_done) {
            SDL_DestroySemaphore(cond->wait_done);
        }
        if (cond->lock) {
            SDL_DestroyMutex(cond->lock);
        }
        SDL_free(cond);
    }
}

/* Restart one of the threads that are waiting on the condition variable */
int
SDL_CondSignal(SDL_cond * cond)
{
    if (!cond) {
        SDL_SetError("Passed a NULL condition variable");
        return -1;
    }

    /* If there are waiting threads not already signalled, then
       signal the condition and wait for the thread to respond.
     */
    SDL_LockMutex(cond->lock);
    if (cond->waiting > cond->signals) {
        ++cond->signals;
        SDL_SemPost(cond->wait_sem);
        SDL_UnlockMutex(cond->lock);
        SDL_SemWait(cond->wait_done);
    } else {
        SDL_UnlockMutex(cond->lock);
    }

    return 0;
}

/* Restart all threads that are waiting on the condition variable */
int
SDL_CondBroadcast(SDL_cond * cond)
{
    if (!cond) {
        SDL_SetError("Passed a NULL condition variable");
        return -1;
    }

    /* If there are waiting threads not already signalled, then
       signal the condition and wait for the thread to respond.
     */
    SDL_LockMutex(cond->lock);
    if (cond->waiting > cond->signals) {
        int i, num_waiting;

        num_waiting = (cond->waiting - cond->signals);
        cond->signals = cond->waiting;
        for (i = 0; i < num_waiting; ++i) {
            SDL_SemPost(cond->wait_sem);
        }
        /* Now all released threads are blocked here, waiting for us.
           Collect them all (and win fabulous prizes!) :-)
         */
        SDL_UnlockMutex(cond->lock);
        for (i = 0; i < num_waiting; ++i) {
            SDL_SemWait(cond->wait_done);
        }
    } else {
        SDL_UnlockMutex(cond->lock);
    }

    return 0;
}

/* Wait on the condition variable for at most 'ms' milliseconds.
   The mutex must be locked before entering this function!
   The mutex is unlocked during the wait, and locked again after the wait.

Typical use:

Thread A:
	SDL_LockMutex(lock);
	while ( ! condition ) {
		SDL_CondWait(cond);
	}
	SDL_UnlockMutex(lock);

Thread B:
	SDL_LockMutex(lock);
	...
	condition = true;
	...
	SDL_UnlockMutex(lock);
 */
int
SDL_CondWaitTimeout(SDL_cond * cond, SDL_mutex * mutex, Uint32 ms)
{
    int retval;

    if (!cond) {
        SDL_SetError("Passed a NULL condition variable");
        return -1;
    }

    /* Obtain the protection mutex, and increment the number of waiters.
       This allows the signal mechanism to only perform a signal if there
       are waiting threads.
     */
    SDL_LockMutex(cond->lock);
    ++cond->waiting;
    SDL_UnlockMutex(cond->lock);

    /* Unlock the mutex, as is required by condition variable semantics */
    SDL_UnlockMutex(mutex);

    /* Wait for a signal */
    if (ms == SDL_MUTEX_MAXWAIT) {
        retval = SDL_SemWait(cond->wait_sem);
    } else {
        retval = SDL_SemWaitTimeout(cond->wait_sem, ms);
    }

    /* Let the signaler know we have completed the wait, otherwise
       the signaler can race ahead and get the condition semaphore
       if we are stopped between the mutex unlock and semaphore wait,
       giving a deadlock.  See the following URL for details:
       http://www-classic.be.com/aboutbe/benewsletter/volume_III/Issue40.html
     */
    SDL_LockMutex(cond->lock);
    if (cond->signals > 0) {
        /* If we timed out, we need to eat a condition signal */
        if (retval > 0) {
            SDL_SemWait(cond->wait_sem);
        }
        /* We always notify the signal thread that we are done */
        SDL_SemPost(cond->wait_done);

        /* Signal handshake complete */
        --cond->signals;
    }
    --cond->waiting;
    SDL_UnlockMutex(cond->lock);

    /* Lock the mutex, as is required by condition variable semantics */
    SDL_LockMutex(mutex);

    return retval;
}

/* Wait on the condition variable forever */
int
SDL_CondWait(SDL_cond * cond, SDL_mutex * mutex)
{
    return SDL_CondWaitTimeout(cond, mutex, SDL_MUTEX_MAXWAIT);
}

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