This repository has been archived by the owner on Feb 11, 2021. It is now read-only.
SDL_syssem.c
1
2
/*
SDL - Simple DirectMedia Layer
3
Copyright (C) 1997-2009 Sam Lantinga
4
5
This library is free software; you can redistribute it and/or
6
modify it under the terms of the GNU Lesser General Public
7
License as published by the Free Software Foundation; either
8
version 2.1 of the License, or (at your option) any later version.
9
10
11
12
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
13
Lesser General Public License for more details.
15
16
17
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
18
19
Sam Lantinga
20
slouken@libsdl.org
21
*/
22
#include "SDL_config.h"
23
24
25
26
27
28
29
30
/* Semaphores in the BeOS environment */
#include <be/kernel/OS.h>
#include "SDL_thread.h"
31
32
33
struct SDL_semaphore
{
sem_id id;
34
35
36
};
/* Create a counting semaphore */
37
38
SDL_sem *
SDL_CreateSemaphore(Uint32 initial_value)
40
41
42
43
44
45
46
47
48
49
50
51
52
53
SDL_sem *sem;
sem = (SDL_sem *) SDL_malloc(sizeof(*sem));
if (sem) {
sem->id = create_sem(initial_value, "SDL semaphore");
if (sem->id < B_NO_ERROR) {
SDL_SetError("create_sem() failed");
SDL_free(sem);
sem = NULL;
}
} else {
SDL_OutOfMemory();
}
return (sem);
54
55
56
}
/* Free the semaphore */
57
58
void
SDL_DestroySemaphore(SDL_sem * sem)
60
61
62
63
64
65
if (sem) {
if (sem->id >= B_NO_ERROR) {
delete_sem(sem->id);
}
SDL_free(sem);
}
66
67
}
68
69
int
SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout)
71
72
int32 val;
int retval;
74
75
76
77
if (!sem) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
78
79
tryagain:
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
if (timeout == SDL_MUTEX_MAXWAIT) {
val = acquire_sem(sem->id);
} else {
timeout *= 1000; /* BeOS uses a timeout in microseconds */
val = acquire_sem_etc(sem->id, 1, B_RELATIVE_TIMEOUT, timeout);
}
switch (val) {
case B_INTERRUPTED:
goto tryagain;
case B_NO_ERROR:
retval = 0;
break;
case B_TIMED_OUT:
retval = SDL_MUTEX_TIMEDOUT;
break;
case B_WOULD_BLOCK:
retval = SDL_MUTEX_TIMEDOUT;
break;
default:
SDL_SetError("acquire_sem() failed");
retval = -1;
break;
}
return retval;
105
106
}
107
108
int
SDL_SemTryWait(SDL_sem * sem)
109
{
110
return SDL_SemWaitTimeout(sem, 0);
111
112
}
113
114
int
SDL_SemWait(SDL_sem * sem)
115
{
116
return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT);
117
118
119
}
/* Returns the current count of the semaphore */
120
121
Uint32
SDL_SemValue(SDL_sem * sem)
122
{
123
124
125
126
127
128
129
130
131
132
133
int32 count;
Uint32 value;
value = 0;
if (sem) {
get_sem_count(sem->id, &count);
if (count > 0) {
value = (Uint32) count;
}
}
return value;
134
135
136
}
/* Atomically increases the semaphore's count (not blocking) */
137
138
int
SDL_SemPost(SDL_sem * sem)
139
{
140
141
142
143
144
145
146
147
148
149
if (!sem) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
if (release_sem(sem->id) != B_NO_ERROR) {
SDL_SetError("release_sem() failed");
return -1;
}
return 0;
150
}
151
152
/* vi: set ts=4 sw=4 expandtab: */