e14743d1 |
1 | /* |
2 | SDL - Simple DirectMedia Layer |
3 | Copyright (C) 1997-2009 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 | /* Semaphores in the BeOS environment */ |
25 | |
26 | #include <be/kernel/OS.h> |
27 | |
28 | #include "SDL_thread.h" |
29 | |
30 | |
31 | struct SDL_semaphore { |
32 | sem_id id; |
33 | }; |
34 | |
35 | /* Create a counting semaphore */ |
36 | SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) |
37 | { |
38 | SDL_sem *sem; |
39 | |
40 | sem = (SDL_sem *)SDL_malloc(sizeof(*sem)); |
41 | if ( sem ) { |
42 | sem->id = create_sem(initial_value, "SDL semaphore"); |
43 | if ( sem->id < B_NO_ERROR ) { |
44 | SDL_SetError("create_sem() failed"); |
45 | SDL_free(sem); |
46 | sem = NULL; |
47 | } |
48 | } else { |
49 | SDL_OutOfMemory(); |
50 | } |
51 | return(sem); |
52 | } |
53 | |
54 | /* Free the semaphore */ |
55 | void SDL_DestroySemaphore(SDL_sem *sem) |
56 | { |
57 | if ( sem ) { |
58 | if ( sem->id >= B_NO_ERROR ) { |
59 | delete_sem(sem->id); |
60 | } |
61 | SDL_free(sem); |
62 | } |
63 | } |
64 | |
65 | int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) |
66 | { |
67 | int32 val; |
68 | int retval; |
69 | |
70 | if ( ! sem ) { |
71 | SDL_SetError("Passed a NULL semaphore"); |
72 | return -1; |
73 | } |
74 | |
75 | tryagain: |
76 | if ( timeout == SDL_MUTEX_MAXWAIT ) { |
77 | val = acquire_sem(sem->id); |
78 | } else { |
79 | timeout *= 1000; /* BeOS uses a timeout in microseconds */ |
80 | val = acquire_sem_etc(sem->id, 1, B_RELATIVE_TIMEOUT, timeout); |
81 | } |
82 | switch (val) { |
83 | case B_INTERRUPTED: |
84 | goto tryagain; |
85 | case B_NO_ERROR: |
86 | retval = 0; |
87 | break; |
88 | case B_TIMED_OUT: |
89 | retval = SDL_MUTEX_TIMEDOUT; |
90 | break; |
91 | case B_WOULD_BLOCK: |
92 | retval = SDL_MUTEX_TIMEDOUT; |
93 | break; |
94 | default: |
95 | SDL_SetError("acquire_sem() failed"); |
96 | retval = -1; |
97 | break; |
98 | } |
99 | |
100 | return retval; |
101 | } |
102 | |
103 | int SDL_SemTryWait(SDL_sem *sem) |
104 | { |
105 | return SDL_SemWaitTimeout(sem, 0); |
106 | } |
107 | |
108 | int SDL_SemWait(SDL_sem *sem) |
109 | { |
110 | return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT); |
111 | } |
112 | |
113 | /* Returns the current count of the semaphore */ |
114 | Uint32 SDL_SemValue(SDL_sem *sem) |
115 | { |
116 | int32 count; |
117 | Uint32 value; |
118 | |
119 | value = 0; |
120 | if ( sem ) { |
121 | get_sem_count(sem->id, &count); |
122 | if ( count > 0 ) { |
123 | value = (Uint32)count; |
124 | } |
125 | } |
126 | return value; |
127 | } |
128 | |
129 | /* Atomically increases the semaphore's count (not blocking) */ |
130 | int SDL_SemPost(SDL_sem *sem) |
131 | { |
132 | if ( ! sem ) { |
133 | SDL_SetError("Passed a NULL semaphore"); |
134 | return -1; |
135 | } |
136 | |
137 | if ( release_sem(sem->id) != B_NO_ERROR ) { |
138 | SDL_SetError("release_sem() failed"); |
139 | return -1; |
140 | } |
141 | return 0; |
142 | } |