Mercurial > sdl-ios-xcode
annotate src/thread/generic/SDL_syssem.c @ 1102:f0919504adfd
Revert back change between 1.29 and 1.30
author | Patrice Mandin <patmandin@gmail.com> |
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date | Wed, 27 Jul 2005 16:30:12 +0000 |
parents | b8d311d90021 |
children | c9b51268668f |
rev | line source |
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0 | 1 /* |
2 SDL - Simple DirectMedia Layer | |
769
b8d311d90021
Updated copyright information for 2004 (Happy New Year!)
Sam Lantinga <slouken@libsdl.org>
parents:
297
diff
changeset
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3 Copyright (C) 1997-2004 Sam Lantinga |
0 | 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 | |
252
e8157fcb3114
Updated the source with the correct e-mail address
Sam Lantinga <slouken@libsdl.org>
parents:
0
diff
changeset
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20 slouken@libsdl.org |
0 | 21 */ |
22 | |
23 #ifdef SAVE_RCSID | |
24 static char rcsid = | |
25 "@(#) $Id$"; | |
26 #endif | |
27 | |
28 /* An implementation of semaphores using mutexes and condition variables */ | |
29 | |
30 #include <stdlib.h> | |
31 | |
32 #include "SDL_error.h" | |
33 #include "SDL_timer.h" | |
34 #include "SDL_thread.h" | |
35 #include "SDL_systhread_c.h" | |
36 | |
37 | |
38 #ifdef DISABLE_THREADS | |
39 | |
40 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) | |
41 { | |
42 SDL_SetError("SDL not configured with thread support"); | |
43 return (SDL_sem *)0; | |
44 } | |
45 | |
46 void SDL_DestroySemaphore(SDL_sem *sem) | |
47 { | |
48 return; | |
49 } | |
50 | |
51 int SDL_SemTryWait(SDL_sem *sem) | |
52 { | |
53 SDL_SetError("SDL not configured with thread support"); | |
54 return -1; | |
55 } | |
56 | |
57 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) | |
58 { | |
59 SDL_SetError("SDL not configured with thread support"); | |
60 return -1; | |
61 } | |
62 | |
63 int SDL_SemWait(SDL_sem *sem) | |
64 { | |
65 SDL_SetError("SDL not configured with thread support"); | |
66 return -1; | |
67 } | |
68 | |
69 Uint32 SDL_SemValue(SDL_sem *sem) | |
70 { | |
71 return 0; | |
72 } | |
73 | |
74 int SDL_SemPost(SDL_sem *sem) | |
75 { | |
76 SDL_SetError("SDL not configured with thread support"); | |
77 return -1; | |
78 } | |
79 | |
80 #else | |
81 | |
82 struct SDL_semaphore | |
83 { | |
84 Uint32 count; | |
85 Uint32 waiters_count; | |
86 SDL_mutex *count_lock; | |
87 SDL_cond *count_nonzero; | |
88 }; | |
89 | |
90 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) | |
91 { | |
92 SDL_sem *sem; | |
93 | |
94 sem = (SDL_sem *)malloc(sizeof(*sem)); | |
95 if ( ! sem ) { | |
96 SDL_OutOfMemory(); | |
97 return(0); | |
98 } | |
99 sem->count = initial_value; | |
100 sem->waiters_count = 0; | |
101 | |
102 sem->count_lock = SDL_CreateMutex(); | |
103 sem->count_nonzero = SDL_CreateCond(); | |
104 if ( ! sem->count_lock || ! sem->count_nonzero ) { | |
105 SDL_DestroySemaphore(sem); | |
106 return(0); | |
107 } | |
108 | |
109 return(sem); | |
110 } | |
111 | |
112 /* WARNING: | |
113 You cannot call this function when another thread is using the semaphore. | |
114 */ | |
115 void SDL_DestroySemaphore(SDL_sem *sem) | |
116 { | |
117 if ( sem ) { | |
118 sem->count = 0xFFFFFFFF; | |
119 while ( sem->waiters_count > 0) { | |
120 SDL_CondSignal(sem->count_nonzero); | |
121 SDL_Delay(10); | |
122 } | |
123 SDL_DestroyCond(sem->count_nonzero); | |
124 SDL_mutexP(sem->count_lock); | |
125 SDL_mutexV(sem->count_lock); | |
126 SDL_DestroyMutex(sem->count_lock); | |
127 free(sem); | |
128 } | |
129 } | |
130 | |
131 int SDL_SemTryWait(SDL_sem *sem) | |
132 { | |
133 int retval; | |
134 | |
135 if ( ! sem ) { | |
136 SDL_SetError("Passed a NULL semaphore"); | |
137 return -1; | |
138 } | |
139 | |
140 retval = SDL_MUTEX_TIMEDOUT; | |
141 SDL_LockMutex(sem->count_lock); | |
142 if ( sem->count > 0 ) { | |
143 --sem->count; | |
144 retval = 0; | |
145 } | |
146 SDL_UnlockMutex(sem->count_lock); | |
147 | |
148 return retval; | |
149 } | |
150 | |
151 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) | |
152 { | |
153 int retval; | |
154 | |
155 if ( ! sem ) { | |
156 SDL_SetError("Passed a NULL semaphore"); | |
157 return -1; | |
158 } | |
159 | |
160 /* A timeout of 0 is an easy case */ | |
161 if ( timeout == 0 ) { | |
162 return SDL_SemTryWait(sem); | |
163 } | |
164 | |
165 SDL_LockMutex(sem->count_lock); | |
166 ++sem->waiters_count; | |
167 retval = 0; | |
168 while ( (sem->count == 0) && (retval != SDL_MUTEX_TIMEDOUT) ) { | |
169 retval = SDL_CondWaitTimeout(sem->count_nonzero, | |
170 sem->count_lock, timeout); | |
171 } | |
172 --sem->waiters_count; | |
173 --sem->count; | |
174 SDL_UnlockMutex(sem->count_lock); | |
175 | |
176 return retval; | |
177 } | |
178 | |
179 int SDL_SemWait(SDL_sem *sem) | |
180 { | |
181 return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT); | |
182 } | |
183 | |
184 Uint32 SDL_SemValue(SDL_sem *sem) | |
185 { | |
186 Uint32 value; | |
187 | |
188 value = 0; | |
189 if ( sem ) { | |
190 SDL_LockMutex(sem->count_lock); | |
191 value = sem->count; | |
192 SDL_UnlockMutex(sem->count_lock); | |
193 } | |
194 return value; | |
195 } | |
196 | |
197 int SDL_SemPost(SDL_sem *sem) | |
198 { | |
199 if ( ! sem ) { | |
200 SDL_SetError("Passed a NULL semaphore"); | |
201 return -1; | |
202 } | |
203 | |
204 SDL_LockMutex(sem->count_lock); | |
205 if ( sem->waiters_count > 0 ) { | |
206 SDL_CondSignal(sem->count_nonzero); | |
207 } | |
208 ++sem->count; | |
209 SDL_UnlockMutex(sem->count_lock); | |
210 | |
211 return 0; | |
212 } | |
213 | |
214 #endif /* DISABLE_THREADS */ |