src/thread/irix/SDL_syssem.c
changeset 1361 19418e4422cb
child 1402 d910939febfa
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/thread/irix/SDL_syssem.c	Thu Feb 16 10:11:48 2006 +0000
@@ -0,0 +1,235 @@
+/*
+    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_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;
+	key_t key;
+
+	sem = (SDL_sem *)SDL_malloc(sizeof(*sem));
+	if ( sem == NULL ) {
+		SDL_OutOfMemory();
+		return(NULL);
+	}
+	/* This flag is true if we are creating the thread manager sem,
+	   which is never freed.  This allows us to reuse the same sem.
+	*/
+	if ( _creating_thread_lock ) {
+		key = 'S'+'D'+'L';
+	} else {
+		key = IPC_PRIVATE;
+	}
+	/* Keep trying to create sem while we don't own the requested key */
+	do {
+		if ( key != IPC_PRIVATE ) {
+			++key;
+		}
+		sem->id = semget(key, 1, (0600|IPC_CREAT));
+	} while ((sem->id < 0) && (key != IPC_PRIVATE) && (errno == EACCES));
+
+	/* Report the error if we eventually failed */
+	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 _SGI_SOURCE
+		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 _SGI_SOURCE
+		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;
+}