build: fix standalone compilation of OMA muxer
[libav.git] / libavcodec / w32pthreads.h
1 /*
2 * Copyright (C) 2010-2011 x264 project
3 *
4 * Authors: Steven Walters <kemuri9@gmail.com>
5 * Pegasys Inc. <http://www.pegasys-inc.com>
6 *
7 * This file is part of Libav.
8 *
9 * Libav is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * Libav is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with Libav; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24 /**
25 * @file
26 * w32threads to pthreads wrapper
27 */
28
29 #ifndef AVCODEC_W32PTHREADS_H
30 #define AVCODEC_W32PTHREADS_H
31
32 /* Build up a pthread-like API using underlying Windows API. Have only static
33 * methods so as to not conflict with a potentially linked in pthread-win32
34 * library.
35 * As most functions here are used without checking return values,
36 * only implement return values as necessary. */
37
38 #define WIN32_LEAN_AND_MEAN
39 #include <windows.h>
40 #include <process.h>
41
42 typedef struct {
43 void *handle;
44 void *(*func)(void* arg);
45 void *arg;
46 void *ret;
47 } pthread_t;
48
49 /* the conditional variable api for windows 6.0+ uses critical sections and
50 * not mutexes */
51 typedef CRITICAL_SECTION pthread_mutex_t;
52
53 /* This is the CONDITIONAL_VARIABLE typedef for using Window's native
54 * conditional variables on kernels 6.0+.
55 * MinGW does not currently have this typedef. */
56 typedef struct {
57 void *ptr;
58 } pthread_cond_t;
59
60 /* function pointers to conditional variable API on windows 6.0+ kernels */
61 static void (WINAPI *cond_broadcast)(pthread_cond_t *cond);
62 static void (WINAPI *cond_init)(pthread_cond_t *cond);
63 static void (WINAPI *cond_signal)(pthread_cond_t *cond);
64 static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex,
65 DWORD milliseconds);
66
67 static unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
68 {
69 pthread_t *h = arg;
70 h->ret = h->func(h->arg);
71 return 0;
72 }
73
74 static int pthread_create(pthread_t *thread, const void *unused_attr,
75 void *(*start_routine)(void*), void *arg)
76 {
77 thread->func = start_routine;
78 thread->arg = arg;
79 thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
80 0, NULL);
81 return !thread->handle;
82 }
83
84 static void pthread_join(pthread_t thread, void **value_ptr)
85 {
86 DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
87 if (ret != WAIT_OBJECT_0)
88 return;
89 if (value_ptr)
90 *value_ptr = thread.ret;
91 CloseHandle(thread.handle);
92 }
93
94 static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr)
95 {
96 InitializeCriticalSection(m);
97 return 0;
98 }
99 static inline int pthread_mutex_destroy(pthread_mutex_t *m)
100 {
101 DeleteCriticalSection(m);
102 return 0;
103 }
104 static inline int pthread_mutex_lock(pthread_mutex_t *m)
105 {
106 EnterCriticalSection(m);
107 return 0;
108 }
109 static inline int pthread_mutex_unlock(pthread_mutex_t *m)
110 {
111 LeaveCriticalSection(m);
112 return 0;
113 }
114
115 /* for pre-Windows 6.0 platforms we need to define and use our own condition
116 * variable and api */
117 typedef struct {
118 pthread_mutex_t mtx_broadcast;
119 pthread_mutex_t mtx_waiter_count;
120 volatile int waiter_count;
121 HANDLE semaphore;
122 HANDLE waiters_done;
123 int is_broadcast;
124 } win32_cond_t;
125
126 static void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
127 {
128 win32_cond_t *win32_cond = NULL;
129 if (cond_init) {
130 cond_init(cond);
131 return;
132 }
133
134 /* non native condition variables */
135 win32_cond = av_mallocz(sizeof(win32_cond_t));
136 if (!win32_cond)
137 return;
138 cond->ptr = win32_cond;
139 win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
140 if (!win32_cond->semaphore)
141 return;
142 win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
143 if (!win32_cond->waiters_done)
144 return;
145
146 pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
147 pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
148 }
149
150 static void pthread_cond_destroy(pthread_cond_t *cond)
151 {
152 win32_cond_t *win32_cond = cond->ptr;
153 /* native condition variables do not destroy */
154 if (cond_init)
155 return;
156
157 /* non native condition variables */
158 CloseHandle(win32_cond->semaphore);
159 CloseHandle(win32_cond->waiters_done);
160 pthread_mutex_destroy(&win32_cond->mtx_waiter_count);
161 pthread_mutex_destroy(&win32_cond->mtx_broadcast);
162 av_freep(&win32_cond);
163 cond->ptr = NULL;
164 }
165
166 static void pthread_cond_broadcast(pthread_cond_t *cond)
167 {
168 win32_cond_t *win32_cond = cond->ptr;
169 int have_waiter;
170
171 if (cond_broadcast) {
172 cond_broadcast(cond);
173 return;
174 }
175
176 /* non native condition variables */
177 pthread_mutex_lock(&win32_cond->mtx_broadcast);
178 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
179 have_waiter = 0;
180
181 if (win32_cond->waiter_count) {
182 win32_cond->is_broadcast = 1;
183 have_waiter = 1;
184 }
185
186 if (have_waiter) {
187 ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
188 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
189 WaitForSingleObject(win32_cond->waiters_done, INFINITE);
190 win32_cond->is_broadcast = 0;
191 } else
192 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
193 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
194 }
195
196 static void pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
197 {
198 win32_cond_t *win32_cond = cond->ptr;
199 int last_waiter;
200 if (cond_wait) {
201 cond_wait(cond, mutex, INFINITE);
202 return;
203 }
204
205 /* non native condition variables */
206 pthread_mutex_lock(&win32_cond->mtx_broadcast);
207 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
208 win32_cond->waiter_count++;
209 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
210 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
211
212 // unlock the external mutex
213 pthread_mutex_unlock(mutex);
214 WaitForSingleObject(win32_cond->semaphore, INFINITE);
215
216 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
217 win32_cond->waiter_count--;
218 last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast;
219 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
220
221 if (last_waiter)
222 SetEvent(win32_cond->waiters_done);
223
224 // lock the external mutex
225 return pthread_mutex_lock(mutex);
226 }
227
228 static void pthread_cond_signal(pthread_cond_t *cond)
229 {
230 win32_cond_t *win32_cond = cond->ptr;
231 int have_waiter;
232 if (cond_signal) {
233 cond_signal(cond);
234 return;
235 }
236
237 pthread_mutex_lock(&win32_cond->mtx_broadcast);
238
239 /* non-native condition variables */
240 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
241 have_waiter = win32_cond->waiter_count;
242 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
243
244 if (have_waiter) {
245 ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
246 WaitForSingleObject(win32_cond->waiters_done, INFINITE);
247 ResetEvent(win32_cond->waiters_done);
248 }
249
250 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
251 }
252
253 static void w32thread_init(void)
254 {
255 HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
256 /* if one is available, then they should all be available */
257 cond_init =
258 (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
259 cond_broadcast =
260 (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
261 cond_signal =
262 (void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
263 cond_wait =
264 (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
265 }
266
267 #endif /* AVCODEC_W32PTHREADS_H */