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comparison src/thread/amigaos/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 75a95f82bc1f
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-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 /* An native implementation of semaphores on AmigaOS */
29
30 #include "SDL_error.h"
31 #include "SDL_thread.h"
32 #include "SDL_systhread_c.h"
33
34
35 struct SDL_semaphore
36 {
37 struct SignalSemaphore Sem;
38 };
39
40 #undef D(x)
41
42 #define D(x)
43
44 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value)
45 {
46 SDL_sem *sem;
47
48 sem = (SDL_sem *)malloc(sizeof(*sem));
49 if ( ! sem ) {
50 SDL_OutOfMemory();
51 return(0);
52 }
53 memset(sem, 0, sizeof(*sem));
54
55 D(bug("Creating semaphore %lx...\n",sem));
56
57 InitSemaphore(&sem->Sem);
58 #if 1 // Allow multiple obtainings of the semaphore
59 while ( initial_value-- ) {
60 ReleaseSemaphore(&sem->Sem);
61 }
62 #endif
63 return(sem);
64 }
65
66 void SDL_DestroySemaphore(SDL_sem *sem)
67 {
68 D(bug("Destroying semaphore %lx...\n",sem));
69
70 if ( sem ) {
71 // Condizioni per liberare i task in attesa?
72 free(sem);
73 }
74 }
75
76 int SDL_SemTryWait(SDL_sem *sem)
77 {
78 int retval;
79
80 if ( ! sem ) {
81 SDL_SetError("Passed a NULL semaphore");
82 return -1;
83 }
84
85 D(bug("TryWait semaphore...%lx\n",sem));
86
87 retval = SDL_MUTEX_TIMEDOUT;
88 if ( AttemptSemaphore(&sem->Sem) ) {
89 retval = 0;
90 }
91 return retval;
92 }
93
94 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)
95 {
96 int retval;
97
98 if ( ! sem ) {
99 SDL_SetError("Passed a NULL semaphore");
100 return -1;
101 }
102
103 D(bug("WaitTimeout (%ld) semaphore...%lx\n",timeout,sem));
104
105 #if 1 // We need to keep trying the semaphore until the timeout expires
106 retval = SDL_MUTEX_TIMEDOUT;
107 then = SDL_GetTicks();
108 do {
109 if ( AttemptSemaphore(&sem->Sem) ) {
110 retval = 0;
111 }
112 now = SDL_GetTicks();
113 } while ( (retval == SDL_MUTEX_TIMEDOUT) && ((now-then) < timeout) );
114 #else
115 if(!(retval=AttemptSemaphore(&sem->Sem)))
116 {
117 SDL_Delay(timeout);
118 retval=AttemptSemaphore(&sem->Sem);
119 }
120
121 if(retval==TRUE)
122 {
123 // ReleaseSemaphore(&sem->Sem);
124 retval=1;
125 }
126 #endif
127 return retval;
128 }
129
130 int SDL_SemWait(SDL_sem *sem)
131 {
132 if ( ! sem ) {
133 SDL_SetError("Passed a NULL semaphore");
134 return -1;
135 }
136 #if 1 // This should be an infinite wait - FIXME, what is the return value?
137 ObtainSemaphore(&sem->Sem);
138 return 0;
139 #else
140 return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT);
141 #endif
142 }
143
144 Uint32 SDL_SemValue(SDL_sem *sem)
145 {
146 Uint32 value;
147
148 value = 0;
149 if ( sem ) {
150 value = sem->Sem.ss_NestCount;
151 }
152 return value;
153 }
154
155 int SDL_SemPost(SDL_sem *sem)
156 {
157 if ( ! sem ) {
158 SDL_SetError("Passed a NULL semaphore");
159 return -1;
160 }
161 D(bug("SemPost semaphore...%lx\n",sem));
162
163 ReleaseSemaphore(&sem->Sem);
164 return 0;
165 }
166