1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997-2012 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 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 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with this library; if not, write to the Free Software
17 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 /* Semaphore functions using the OS/2 API */
25
26 #define INCL_DOS
27 #define INCL_DOSERRORS
28 #define INCL_DOSSEMAPHORES
29 #include <os2.h>
30
31 #include "SDL_thread.h"
32 #include "SDL_timer.h"
33
34
35 struct SDL_semaphore {
36 HMTX id;
37 HEV changed;
38 Uint32 value;
39 };
40
41
42 /* Create a semaphore */
SDL_CreateSemaphore(Uint32 initial_value)43 DECLSPEC SDL_sem * SDLCALL SDL_CreateSemaphore(Uint32 initial_value)
44 {
45 SDL_sem *sem;
46 ULONG ulrc;
47
48 /* Allocate sem memory */
49 sem = (SDL_sem *)SDL_malloc(sizeof(*sem));
50 if ( sem ) {
51 /* Create the mutex semaphore */
52 ulrc = DosCreateMutexSem(NULL,&(sem->id),0,TRUE);
53 if ( ulrc ) {
54 SDL_SetError("Couldn't create semaphore");
55 SDL_free(sem);
56 sem = NULL;
57 } else
58 {
59 DosCreateEventSem(NULL, &(sem->changed), 0, FALSE);
60 sem->value = initial_value;
61 DosReleaseMutexSem(sem->id);
62 }
63 } else {
64 SDL_OutOfMemory();
65 }
66 return(sem);
67 }
68
69 /* Free the semaphore */
SDL_DestroySemaphore(SDL_sem * sem)70 DECLSPEC void SDLCALL SDL_DestroySemaphore(SDL_sem *sem)
71 {
72 if ( sem ) {
73 if ( sem->id ) {
74 DosCloseEventSem(sem->changed);
75 DosCloseMutexSem(sem->id);
76 sem->id = 0;
77 }
78 SDL_free(sem);
79 }
80 }
81
SDL_SemWaitTimeout(SDL_sem * sem,Uint32 timeout)82 DECLSPEC int SDLCALL SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)
83 {
84 ULONG ulrc;
85
86 if ( ! sem ) {
87 SDL_SetError("Passed a NULL sem");
88 return -1;
89 }
90
91 if ( timeout == SDL_MUTEX_MAXWAIT ) {
92 while (1) {
93 ulrc = DosRequestMutexSem(sem->id, SEM_INDEFINITE_WAIT);
94 if (ulrc) {
95 /* if error waiting mutex */
96 SDL_SetError("DosRequestMutexSem() failed");
97 return -1;
98 } else if (sem->value) {
99 sem->value--;
100 DosReleaseMutexSem(sem->id);
101 return 0;
102 } else {
103 ULONG ulPostCount;
104 DosResetEventSem(sem->changed, &ulPostCount);
105 DosReleaseMutexSem(sem->id);
106 /* continue waiting until somebody posts the semaphore */
107 DosWaitEventSem(sem->changed, SEM_INDEFINITE_WAIT);
108 }
109 }
110 } else
111 if ( timeout == 0 )
112 {
113 ulrc = DosRequestMutexSem(sem->id, SEM_INDEFINITE_WAIT);
114 if (ulrc==NO_ERROR)
115 {
116 if (sem->value)
117 {
118 sem->value--;
119 DosReleaseMutexSem(sem->id);
120 return 0;
121 } else
122 {
123 DosReleaseMutexSem(sem->id);
124 return SDL_MUTEX_TIMEDOUT;
125 }
126 } else
127 {
128 SDL_SetError("DosRequestMutexSem() failed");
129 return -1;
130 }
131 } else {
132 ulrc = DosRequestMutexSem(sem->id, SEM_INDEFINITE_WAIT);
133 if (ulrc) {
134 /* if error waiting mutex */
135 SDL_SetError("DosRequestMutexSem() failed");
136 return -1;
137 } else
138 if (sem->value) {
139 sem->value--;
140 DosReleaseMutexSem(sem->id);
141 return 0;
142 } else {
143 ULONG ulPostCount;
144 DosResetEventSem(sem->changed, &ulPostCount);
145 DosReleaseMutexSem(sem->id);
146 /* continue waiting until somebody posts the semaphore */
147 ulrc = DosWaitEventSem(sem->changed, timeout);
148 if (ulrc==NO_ERROR)
149 return 0;
150 else
151 return SDL_MUTEX_TIMEDOUT;
152 }
153 }
154 /* never reached */
155 return -1;
156 }
157
SDL_SemTryWait(SDL_sem * sem)158 DECLSPEC int SDLCALL SDL_SemTryWait(SDL_sem *sem)
159 {
160 return SDL_SemWaitTimeout(sem, 0);
161 }
162
SDL_SemWait(SDL_sem * sem)163 DECLSPEC int SDLCALL SDL_SemWait(SDL_sem *sem)
164 {
165 return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT);
166 }
167
168 /* Returns the current count of the semaphore */
SDL_SemValue(SDL_sem * sem)169 DECLSPEC Uint32 SDLCALL SDL_SemValue(SDL_sem *sem)
170 {
171 if ( ! sem ) {
172 SDL_SetError("Passed a NULL sem");
173 return 0;
174 }
175 return sem->value;
176 }
177
SDL_SemPost(SDL_sem * sem)178 DECLSPEC int SDLCALL SDL_SemPost(SDL_sem *sem)
179 {
180 if ( ! sem ) {
181 SDL_SetError("Passed a NULL sem");
182 return -1;
183 }
184 if ( DosRequestMutexSem(sem->id,SEM_INDEFINITE_WAIT) ) {
185 SDL_SetError("DosRequestMutexSem() failed");
186 return -1;
187 }
188 sem->value++;
189 DosPostEventSem(sem->changed);
190 DosReleaseMutexSem(sem->id);
191 return 0;
192 }
193