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 | /* Semaphore functions using the Win32 API */ |
25 | |
26 | #define WIN32_LEAN_AND_MEAN |
27 | #include <windows.h> |
28 | |
29 | #include "SDL_thread.h" |
30 | #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
31 | #include "win_ce_semaphore.h" |
32 | #endif |
33 | |
34 | |
35 | struct SDL_semaphore { |
36 | #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
37 | SYNCHHANDLE id; |
38 | #else |
39 | HANDLE id; |
40 | #endif |
41 | Uint32 volatile count; |
42 | }; |
43 | |
44 | |
45 | /* Create a semaphore */ |
46 | SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) |
47 | { |
48 | SDL_sem *sem; |
49 | |
50 | /* Allocate sem memory */ |
51 | sem = (SDL_sem *)SDL_malloc(sizeof(*sem)); |
52 | if ( sem ) { |
53 | /* Create the semaphore, with max value 32K */ |
54 | #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
55 | sem->id = CreateSemaphoreCE(NULL, initial_value, 32*1024, NULL); |
56 | #else |
57 | sem->id = CreateSemaphore(NULL, initial_value, 32*1024, NULL); |
58 | #endif |
59 | sem->count = initial_value; |
60 | if ( ! sem->id ) { |
61 | SDL_SetError("Couldn't create semaphore"); |
62 | SDL_free(sem); |
63 | sem = NULL; |
64 | } |
65 | } else { |
66 | SDL_OutOfMemory(); |
67 | } |
68 | return(sem); |
69 | } |
70 | |
71 | /* Free the semaphore */ |
72 | void SDL_DestroySemaphore(SDL_sem *sem) |
73 | { |
74 | if ( sem ) { |
75 | if ( sem->id ) { |
76 | #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
77 | CloseSynchHandle(sem->id); |
78 | #else |
79 | CloseHandle(sem->id); |
80 | #endif |
81 | sem->id = 0; |
82 | } |
83 | SDL_free(sem); |
84 | } |
85 | } |
86 | |
87 | int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) |
88 | { |
89 | int retval; |
90 | DWORD dwMilliseconds; |
91 | |
92 | if ( ! sem ) { |
93 | SDL_SetError("Passed a NULL sem"); |
94 | return -1; |
95 | } |
96 | |
97 | if ( timeout == SDL_MUTEX_MAXWAIT ) { |
98 | dwMilliseconds = INFINITE; |
99 | } else { |
100 | dwMilliseconds = (DWORD)timeout; |
101 | } |
102 | #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
103 | switch (WaitForSemaphoreCE(sem->id, dwMilliseconds)) { |
104 | #else |
105 | switch (WaitForSingleObject(sem->id, dwMilliseconds)) { |
106 | #endif |
107 | case WAIT_OBJECT_0: |
108 | InterlockedDecrement(&sem->count); |
109 | retval = 0; |
110 | break; |
111 | case WAIT_TIMEOUT: |
112 | retval = SDL_MUTEX_TIMEDOUT; |
113 | break; |
114 | default: |
115 | SDL_SetError("WaitForSingleObject() failed"); |
116 | retval = -1; |
117 | break; |
118 | } |
119 | return retval; |
120 | } |
121 | |
122 | int SDL_SemTryWait(SDL_sem *sem) |
123 | { |
124 | return SDL_SemWaitTimeout(sem, 0); |
125 | } |
126 | |
127 | int SDL_SemWait(SDL_sem *sem) |
128 | { |
129 | return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT); |
130 | } |
131 | |
132 | /* Returns the current count of the semaphore */ |
133 | Uint32 SDL_SemValue(SDL_sem *sem) |
134 | { |
135 | if ( ! sem ) { |
136 | SDL_SetError("Passed a NULL sem"); |
137 | return 0; |
138 | } |
139 | return sem->count; |
140 | } |
141 | |
142 | int SDL_SemPost(SDL_sem *sem) |
143 | { |
144 | if ( ! sem ) { |
145 | SDL_SetError("Passed a NULL sem"); |
146 | return -1; |
147 | } |
148 | /* Increase the counter in the first place, because |
149 | * after a successful release the semaphore may |
150 | * immediately get destroyed by another thread which |
151 | * is waiting for this semaphore. |
152 | */ |
153 | InterlockedIncrement(&sem->count); |
154 | #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
155 | if ( ReleaseSemaphoreCE(sem->id, 1, NULL) == FALSE ) { |
156 | #else |
157 | if ( ReleaseSemaphore(sem->id, 1, NULL) == FALSE ) { |
158 | #endif |
159 | InterlockedDecrement(&sem->count); /* restore */ |
160 | SDL_SetError("ReleaseSemaphore() failed"); |
161 | return -1; |
162 | } |
163 | return 0; |
164 | } |