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comparison src/thread/beos/SDL_syssem.c @ 0:74212992fb08

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Initial revision
author Sam Lantinga <slouken@lokigames.com>
date Thu, 26 Apr 2001 16:45:43 +0000
parents
children e8157fcb3114
comparison
equal deleted inserted replaced
-1:000000000000 0:74212992fb08
1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public
7 License as published by the Free Software Foundation; either
8 version 2 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with this library; if not, write to the Free
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18
19 Sam Lantinga
20 slouken@devolution.com
21 */
22
23 #ifdef SAVE_RCSID
24 static char rcsid =
25 "@(#) $Id$";
26 #endif
27
28 /* Semaphores in the BeOS environment */
29
30 #include <be/kernel/OS.h>
31
32 #include "SDL_error.h"
33 #include "SDL_thread.h"
34
35
36 struct SDL_semaphore {
37 sem_id id;
38 };
39
40 /* Create a counting semaphore */
41 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value)
42 {
43 SDL_sem *sem;
44
45 sem = (SDL_sem *)malloc(sizeof(*sem));
46 if ( sem ) {
47 sem->id = create_sem(initial_value, "SDL semaphore");
48 if ( sem->id < B_NO_ERROR ) {
49 SDL_SetError("create_sem() failed");
50 free(sem);
51 sem = NULL;
52 }
53 } else {
54 SDL_OutOfMemory();
55 }
56 return(sem);
57 }
58
59 /* Free the semaphore */
60 void SDL_DestroySemaphore(SDL_sem *sem)
61 {
62 if ( sem ) {
63 if ( sem->id >= B_NO_ERROR ) {
64 delete_sem(sem->id);
65 }
66 free(sem);
67 }
68 }
69
70 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)
71 {
72 int32 val;
73 int retval;
74
75 if ( ! sem ) {
76 SDL_SetError("Passed a NULL semaphore");
77 return -1;
78 }
79
80 tryagain:
81 if ( timeout == SDL_MUTEX_MAXWAIT ) {
82 val = acquire_sem(sem->id);
83 } else {
84 timeout *= 1000; /* BeOS uses a timeout in microseconds */
85 val = acquire_sem_etc(sem->id, 1, B_RELATIVE_TIMEOUT, timeout);
86 }
87 switch (val) {
88 case B_INTERRUPTED:
89 goto tryagain;
90 case B_NO_ERROR:
91 retval = 0;
92 break;
93 default:
94 SDL_SetError("acquire_sem() failed");
95 retval = -1;
96 break;
97 }
98
99 return retval;
100 }
101
102 int SDL_SemTryWait(SDL_sem *sem)
103 {
104 return SDL_SemWaitTimeout(sem, 0);
105 }
106
107 int SDL_SemWait(SDL_sem *sem)
108 {
109 return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT);
110 }
111
112 /* Returns the current count of the semaphore */
113 Uint32 SDL_SemValue(SDL_sem *sem)
114 {
115 int32 count;
116 Uint32 value;
117
118 value = 0;
119 if ( sem ) {
120 get_sem_count(sem->id, &count);
121 if ( count > 0 ) {
122 value = (Uint32)count;
123 }
124 }
125 return value;
126 }
127
128 /* Atomically increases the semaphore's count (not blocking) */
129 int SDL_SemPost(SDL_sem *sem)
130 {
131 if ( ! sem ) {
132 SDL_SetError("Passed a NULL semaphore");
133 return -1;
134 }
135
136 if ( release_sem(sem->id) != B_NO_ERROR ) {
137 SDL_SetError("release_sem() failed");
138 return -1;
139 }
140 return 0;
141 }