w32pthreads: Fix function pointer casts
[libav.git] / compat / 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 LIBAV_COMPAT_W32PTHREADS_H
30 #define LIBAV_COMPAT_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 #if _WIN32_WINNT < 0x0600 && defined(__MINGW32__)
43 #undef MemoryBarrier
44 #define MemoryBarrier __sync_synchronize
45 #endif
46
47 #include "libavutil/attributes.h"
48 #include "libavutil/internal.h"
49 #include "libavutil/mem.h"
50
51 typedef struct pthread_t {
52 void *handle;
53 void *(*func)(void* arg);
54 void *arg;
55 void *ret;
56 } pthread_t;
57
58 /* the conditional variable api for windows 6.0+ uses critical sections and
59 * not mutexes */
60 typedef CRITICAL_SECTION pthread_mutex_t;
61
62 /* This is the CONDITION_VARIABLE typedef for using Windows' native
63 * conditional variables on kernels 6.0+. */
64 #if HAVE_CONDITION_VARIABLE_PTR
65 typedef CONDITION_VARIABLE pthread_cond_t;
66 #else
67 typedef struct pthread_cond_t {
68 void *Ptr;
69 } pthread_cond_t;
70 #endif
71
72 #if _WIN32_WINNT >= 0x0600
73 #define InitializeCriticalSection(x) InitializeCriticalSectionEx(x, 0, 0)
74 #define WaitForSingleObject(a, b) WaitForSingleObjectEx(a, b, FALSE)
75 #endif
76
77 static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
78 {
79 pthread_t *h = arg;
80 h->ret = h->func(h->arg);
81 return 0;
82 }
83
84 static av_unused int pthread_create(pthread_t *thread, const void *unused_attr,
85 void *(*start_routine)(void*), void *arg)
86 {
87 thread->func = start_routine;
88 thread->arg = arg;
89 thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
90 0, NULL);
91 return !thread->handle;
92 }
93
94 static av_unused void pthread_join(pthread_t thread, void **value_ptr)
95 {
96 DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
97 if (ret != WAIT_OBJECT_0)
98 return;
99 if (value_ptr)
100 *value_ptr = thread.ret;
101 CloseHandle(thread.handle);
102 }
103
104 static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr)
105 {
106 InitializeCriticalSection(m);
107 return 0;
108 }
109 static inline int pthread_mutex_destroy(pthread_mutex_t *m)
110 {
111 DeleteCriticalSection(m);
112 return 0;
113 }
114 static inline int pthread_mutex_lock(pthread_mutex_t *m)
115 {
116 EnterCriticalSection(m);
117 return 0;
118 }
119 static inline int pthread_mutex_unlock(pthread_mutex_t *m)
120 {
121 LeaveCriticalSection(m);
122 return 0;
123 }
124
125 #if _WIN32_WINNT >= 0x0600
126
127 typedef INIT_ONCE pthread_once_t;
128 #define PTHREAD_ONCE_INIT INIT_ONCE_STATIC_INIT
129
130 static av_unused int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
131 {
132 BOOL pending = FALSE;
133 InitOnceBeginInitialize(once_control, 0, &pending, NULL);
134 if (pending)
135 init_routine();
136 InitOnceComplete(once_control, 0, NULL);
137 return 0;
138 }
139
140 static inline void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
141 {
142 InitializeConditionVariable(cond);
143 }
144
145 /* native condition variables do not destroy */
146 static inline void pthread_cond_destroy(pthread_cond_t *cond)
147 {
148 return;
149 }
150
151 static inline void pthread_cond_broadcast(pthread_cond_t *cond)
152 {
153 WakeAllConditionVariable(cond);
154 }
155
156 static inline int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
157 {
158 SleepConditionVariableCS(cond, mutex, INFINITE);
159 return 0;
160 }
161
162 static inline void pthread_cond_signal(pthread_cond_t *cond)
163 {
164 WakeConditionVariable(cond);
165 }
166
167 #else // _WIN32_WINNT < 0x0600
168
169 /* atomic init state of dynamically loaded functions */
170 static LONG w32thread_init_state = 0;
171 static av_unused void w32thread_init(void);
172
173 /* for pre-Windows 6.0 platforms, define INIT_ONCE struct,
174 * compatible to the one used in the native API */
175
176 typedef union pthread_once_t {
177 void * Ptr; ///< For the Windows 6.0+ native functions
178 LONG state; ///< For the pre-Windows 6.0 compat code
179 } pthread_once_t;
180
181 #define PTHREAD_ONCE_INIT {0}
182
183 /* function pointers to init once API on windows 6.0+ kernels */
184 static BOOL (WINAPI *initonce_begin)(pthread_once_t *lpInitOnce, DWORD dwFlags, BOOL *fPending, void **lpContext);
185 static BOOL (WINAPI *initonce_complete)(pthread_once_t *lpInitOnce, DWORD dwFlags, void *lpContext);
186
187 /* pre-Windows 6.0 compat using a spin-lock */
188 static inline void w32thread_once_fallback(LONG volatile *state, void (*init_routine)(void))
189 {
190 switch (InterlockedCompareExchange(state, 1, 0)) {
191 /* Initial run */
192 case 0:
193 init_routine();
194 InterlockedExchange(state, 2);
195 break;
196 /* Another thread is running init */
197 case 1:
198 while (1) {
199 MemoryBarrier();
200 if (*state == 2)
201 break;
202 Sleep(0);
203 }
204 break;
205 /* Initialization complete */
206 case 2:
207 break;
208 }
209 }
210
211 static av_unused int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
212 {
213 w32thread_once_fallback(&w32thread_init_state, w32thread_init);
214
215 /* Use native functions on Windows 6.0+ */
216 if (initonce_begin && initonce_complete) {
217 BOOL pending = FALSE;
218 initonce_begin(once_control, 0, &pending, NULL);
219 if (pending)
220 init_routine();
221 initonce_complete(once_control, 0, NULL);
222 return 0;
223 }
224
225 w32thread_once_fallback(&once_control->state, init_routine);
226 return 0;
227 }
228
229 /* for pre-Windows 6.0 platforms we need to define and use our own condition
230 * variable and api */
231
232 typedef struct win32_cond_t {
233 pthread_mutex_t mtx_broadcast;
234 pthread_mutex_t mtx_waiter_count;
235 volatile int waiter_count;
236 HANDLE semaphore;
237 HANDLE waiters_done;
238 volatile int is_broadcast;
239 } win32_cond_t;
240
241 /* function pointers to conditional variable API on windows 6.0+ kernels */
242 static void (WINAPI *cond_broadcast)(pthread_cond_t *cond);
243 static void (WINAPI *cond_init)(pthread_cond_t *cond);
244 static void (WINAPI *cond_signal)(pthread_cond_t *cond);
245 static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex,
246 DWORD milliseconds);
247
248 static av_unused void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
249 {
250 win32_cond_t *win32_cond = NULL;
251
252 w32thread_once_fallback(&w32thread_init_state, w32thread_init);
253
254 if (cond_init) {
255 cond_init(cond);
256 return;
257 }
258
259 /* non native condition variables */
260 win32_cond = av_mallocz(sizeof(win32_cond_t));
261 if (!win32_cond)
262 return;
263 cond->Ptr = win32_cond;
264 win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
265 if (!win32_cond->semaphore)
266 return;
267 win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
268 if (!win32_cond->waiters_done)
269 return;
270
271 pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
272 pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
273 }
274
275 static av_unused void pthread_cond_destroy(pthread_cond_t *cond)
276 {
277 win32_cond_t *win32_cond = cond->Ptr;
278 /* native condition variables do not destroy */
279 if (cond_init)
280 return;
281
282 /* non native condition variables */
283 CloseHandle(win32_cond->semaphore);
284 CloseHandle(win32_cond->waiters_done);
285 pthread_mutex_destroy(&win32_cond->mtx_waiter_count);
286 pthread_mutex_destroy(&win32_cond->mtx_broadcast);
287 av_freep(&win32_cond);
288 cond->Ptr = NULL;
289 }
290
291 static av_unused void pthread_cond_broadcast(pthread_cond_t *cond)
292 {
293 win32_cond_t *win32_cond = cond->Ptr;
294 int have_waiter;
295
296 if (cond_broadcast) {
297 cond_broadcast(cond);
298 return;
299 }
300
301 /* non native condition variables */
302 pthread_mutex_lock(&win32_cond->mtx_broadcast);
303 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
304 have_waiter = 0;
305
306 if (win32_cond->waiter_count) {
307 win32_cond->is_broadcast = 1;
308 have_waiter = 1;
309 }
310
311 if (have_waiter) {
312 ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
313 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
314 WaitForSingleObject(win32_cond->waiters_done, INFINITE);
315 ResetEvent(win32_cond->waiters_done);
316 win32_cond->is_broadcast = 0;
317 } else
318 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
319 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
320 }
321
322 static av_unused int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
323 {
324 win32_cond_t *win32_cond = cond->Ptr;
325 int last_waiter;
326 if (cond_wait) {
327 cond_wait(cond, mutex, INFINITE);
328 return 0;
329 }
330
331 /* non native condition variables */
332 pthread_mutex_lock(&win32_cond->mtx_broadcast);
333 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
334 win32_cond->waiter_count++;
335 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
336 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
337
338 // unlock the external mutex
339 pthread_mutex_unlock(mutex);
340 WaitForSingleObject(win32_cond->semaphore, INFINITE);
341
342 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
343 win32_cond->waiter_count--;
344 last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast;
345 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
346
347 if (last_waiter)
348 SetEvent(win32_cond->waiters_done);
349
350 // lock the external mutex
351 return pthread_mutex_lock(mutex);
352 }
353
354 static av_unused void pthread_cond_signal(pthread_cond_t *cond)
355 {
356 win32_cond_t *win32_cond = cond->Ptr;
357 int have_waiter;
358 if (cond_signal) {
359 cond_signal(cond);
360 return;
361 }
362
363 pthread_mutex_lock(&win32_cond->mtx_broadcast);
364
365 /* non-native condition variables */
366 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
367 have_waiter = win32_cond->waiter_count;
368 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
369
370 if (have_waiter) {
371 ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
372 WaitForSingleObject(win32_cond->waiters_done, INFINITE);
373 ResetEvent(win32_cond->waiters_done);
374 }
375
376 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
377 }
378 #endif
379
380 static av_unused void w32thread_init(void)
381 {
382 #if _WIN32_WINNT < 0x0600
383 HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
384 /* if one is available, then they should all be available */
385 cond_init = (void (WINAPI*)(pthread_cond_t *))
386 GetProcAddress(kernel_dll, "InitializeConditionVariable");
387 cond_broadcast = (void (WINAPI*)(pthread_cond_t *))
388 GetProcAddress(kernel_dll, "WakeAllConditionVariable");
389 cond_signal = (void (WINAPI*)(pthread_cond_t *))
390 GetProcAddress(kernel_dll, "WakeConditionVariable");
391 cond_wait = (BOOL (WINAPI*)(pthread_cond_t *, pthread_mutex_t *, DWORD))
392 GetProcAddress(kernel_dll, "SleepConditionVariableCS");
393 initonce_begin = (BOOL (WINAPI*)(pthread_once_t *, DWORD, BOOL *, void **))
394 GetProcAddress(kernel_dll, "InitOnceBeginInitialize");
395 initonce_complete = (BOOL (WINAPI*)(pthread_once_t *, DWORD, void *))
396 GetProcAddress(kernel_dll, "InitOnceComplete");
397 #endif
398
399 }
400
401 #endif /* LIBAV_COMPAT_W32PTHREADS_H */