This repository has been archived by the owner on Feb 11, 2021. It is now read-only.
/
SDL_syssem.c
151 lines (129 loc) · 3.31 KB
1
/*
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Simple DirectMedia Layer
Copyright (C) 1997-2011 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
20
*/
21
#include "SDL_config.h"
22
23
24
25
26
27
28
29
/* Semaphores in the BeOS environment */
#include <be/kernel/OS.h>
#include "SDL_thread.h"
30
31
32
struct SDL_semaphore
{
sem_id id;
33
34
35
};
/* Create a counting semaphore */
36
37
SDL_sem *
SDL_CreateSemaphore(Uint32 initial_value)
38
{
39
40
41
42
43
44
45
46
47
48
49
50
51
52
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);
53
54
55
}
/* Free the semaphore */
56
57
void
SDL_DestroySemaphore(SDL_sem * sem)
58
{
59
60
61
62
63
64
if (sem) {
if (sem->id >= B_NO_ERROR) {
delete_sem(sem->id);
}
SDL_free(sem);
}
65
66
}
67
68
int
SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout)
69
{
70
71
int32 val;
int retval;
72
73
74
75
76
if (!sem) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
77
78
tryagain:
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
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;
104
105
}
106
107
int
SDL_SemTryWait(SDL_sem * sem)
108
{
109
return SDL_SemWaitTimeout(sem, 0);
110
111
}
112
113
int
SDL_SemWait(SDL_sem * sem)
114
{
115
return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT);
116
117
118
}
/* Returns the current count of the semaphore */
119
120
Uint32
SDL_SemValue(SDL_sem * sem)
121
{
122
123
124
125
126
127
128
129
130
131
132
int32 count;
Uint32 value;
value = 0;
if (sem) {
get_sem_count(sem->id, &count);
if (count > 0) {
value = (Uint32) count;
}
}
return value;
133
134
135
}
/* Atomically increases the semaphore's count (not blocking) */
136
137
int
SDL_SemPost(SDL_sem * sem)
138
{
139
140
141
142
143
144
145
146
147
148
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;
149
}
150
151
/* vi: set ts=4 sw=4 expandtab: */