Initial revision

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%401

src/thread/win32/SDL_syssem.c

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+/*
+    SDL - Simple DirectMedia Layer
+    Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 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
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public
+    License along with this library; if not, write to the Free
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+    Sam Lantinga
+    slouken@devolution.com
+*/
+
+#ifdef SAVE_RCSID
+static char rcsid =
+ "@(#) $Id$";
+#endif
+
+/* Semaphore functions using the Win32 API */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <windows.h>
+
+#include "SDL_error.h"
+#include "SDL_thread.h"
+
+#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
+
+/* No semaphores on Windows CE earlier than 3.0, hmm... */
+
+/* Create a semaphore */
+SDL_sem *SDL_CreateSemaphore(Uint32 initial_value)
+{
+	SDL_SetError("Semaphores not supported on WinCE");
+	return(NULL);
+}
+
+/* Free the semaphore */
+void SDL_DestroySemaphore(SDL_sem *sem)
+{
+	return;
+}
+
+int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)
+{
+	SDL_SetError("Semaphores not supported on WinCE");
+	return(-1);
+}
+
+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)
+{
+	return(0);
+}
+
+int SDL_SemPost(SDL_sem *sem)
+{
+	SDL_SetError("Semaphores not supported on WinCE");
+	return(-1);
+}
+
+#else
+
+struct SDL_semaphore {
+	HANDLE id;
+	Uint32 volatile count;
+};
+
+
+/* Create a semaphore */
+SDL_sem *SDL_CreateSemaphore(Uint32 initial_value)
+{
+	SDL_sem *sem;
+
+	/* Allocate sem memory */
+	sem = (SDL_sem *)malloc(sizeof(*sem));
+	if ( sem ) {
+		/* Create the semaphore, with max value 32K */
+		sem->id = CreateSemaphore(NULL, initial_value, 32*1024, NULL);
+		sem->count = initial_value;
+		if ( ! sem->id ) {
+			SDL_SetError("Couldn't create semaphore");
+			free(sem);
+			sem = NULL;
+		}
+	} else {
+		SDL_OutOfMemory();
+	}
+	return(sem);
+}
+
+/* Free the semaphore */
+void SDL_DestroySemaphore(SDL_sem *sem)
+{
+	if ( sem ) {
+		if ( sem->id ) {
+			CloseHandle(sem->id);
+			sem->id = 0;
+		}
+		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;
+	}
+	switch (WaitForSingleObject(sem->id, dwMilliseconds)) {
+	    case WAIT_OBJECT_0:
+		--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.
+	 */
+	++sem->count;
+	if ( ReleaseSemaphore(sem->id, 1, NULL) == FALSE ) {
+		--sem->count;	/* restore */
+		SDL_SetError("ReleaseSemaphore() failed");
+		return -1;
+	}
+	return 0;
+}
+
+#endif /* _WIN32_WCE */