/
SDL_syssem.c
166 lines (134 loc) · 3.26 KB
/
SDL_syssem.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
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
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
/*
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
/* An native implementation of semaphores on AmigaOS */
#include "SDL_error.h"
#include "SDL_thread.h"
#include "SDL_systhread_c.h"
struct SDL_semaphore
{
struct SignalSemaphore Sem;
};
#undef D(x)
#define D(x)
SDL_sem *SDL_CreateSemaphore(Uint32 initial_value)
{
SDL_sem *sem;
sem = (SDL_sem *)malloc(sizeof(*sem));
if ( ! sem ) {
SDL_OutOfMemory();
return(0);
}
memset(sem, 0, sizeof(*sem));
D(bug("Creating semaphore %lx...\n",sem));
InitSemaphore(&sem->Sem);
#if 1 // Allow multiple obtainings of the semaphore
while ( initial_value-- ) {
ReleaseSemaphore(&sem->Sem);
}
#endif
return(sem);
}
void SDL_DestroySemaphore(SDL_sem *sem)
{
D(bug("Destroying semaphore %lx...\n",sem));
if ( sem ) {
// Condizioni per liberare i task in attesa?
free(sem);
}
}
int SDL_SemTryWait(SDL_sem *sem)
{
int retval;
if ( ! sem ) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
D(bug("TryWait semaphore...%lx\n",sem));
retval = SDL_MUTEX_TIMEDOUT;
if ( AttemptSemaphore(&sem->Sem) ) {
retval = 0;
}
return retval;
}
int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)
{
int retval;
if ( ! sem ) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
D(bug("WaitTimeout (%ld) semaphore...%lx\n",timeout,sem));
#if 1 // We need to keep trying the semaphore until the timeout expires
retval = SDL_MUTEX_TIMEDOUT;
then = SDL_GetTicks();
do {
if ( AttemptSemaphore(&sem->Sem) ) {
retval = 0;
}
now = SDL_GetTicks();
} while ( (retval == SDL_MUTEX_TIMEDOUT) && ((now-then) < timeout) );
#else
if(!(retval=AttemptSemaphore(&sem->Sem)))
{
SDL_Delay(timeout);
retval=AttemptSemaphore(&sem->Sem);
}
if(retval==TRUE)
{
// ReleaseSemaphore(&sem->Sem);
retval=1;
}
#endif
return retval;
}
int SDL_SemWait(SDL_sem *sem)
{
if ( ! sem ) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
#if 1 // This should be an infinite wait - FIXME, what is the return value?
ObtainSemaphore(&sem->Sem);
return 0;
#else
return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT);
#endif
}
Uint32 SDL_SemValue(SDL_sem *sem)
{
Uint32 value;
value = 0;
if ( sem ) {
value = sem->Sem.ss_NestCount;
}
return value;
}
int SDL_SemPost(SDL_sem *sem)
{
if ( ! sem ) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
D(bug("SemPost semaphore...%lx\n",sem));
ReleaseSemaphore(&sem->Sem);
return 0;
}