2 * Copyright (C) 2010-2011 x264 project
4 * Authors: Steven Walters <kemuri9@gmail.com>
5 * Pegasys Inc. <http://www.pegasys-inc.com>
7 * This file is part of Libav.
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.
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.
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
26 * w32threads to pthreads wrapper
29 #ifndef LIBAV_COMPAT_W32PTHREADS_H
30 #define LIBAV_COMPAT_W32PTHREADS_H
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
35 * As most functions here are used without checking return values,
36 * only implement return values as necessary. */
38 #define WIN32_LEAN_AND_MEAN
42 /* MinGW requires the intrinsics header for the pthread_once fallback code */
43 #if _WIN32_WINNT < 0x0600 && defined(__MINGW32__)
47 #include "libavutil/attributes.h"
48 #include "libavutil/internal.h"
49 #include "libavutil/mem.h"
51 typedef struct pthread_t {
53 void *(*func)(void* arg);
58 /* the conditional variable api for windows 6.0+ uses critical sections and
60 typedef CRITICAL_SECTION pthread_mutex_t;
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;
67 typedef struct pthread_cond_t {
72 #if _WIN32_WINNT >= 0x0600
73 #define InitializeCriticalSection(x) InitializeCriticalSectionEx(x, 0, 0)
74 #define WaitForSingleObject(a, b) WaitForSingleObjectEx(a, b, FALSE)
77 static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
80 h->ret = h->func(h->arg);
84 static av_unused int pthread_create(pthread_t *thread, const void *unused_attr,
85 void *(*start_routine)(void*), void *arg)
87 thread->func = start_routine;
89 thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
91 return !thread->handle;
94 static av_unused void pthread_join(pthread_t thread, void **value_ptr)
96 DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
97 if (ret != WAIT_OBJECT_0)
100 *value_ptr = thread.ret;
101 CloseHandle(thread.handle);
104 static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr)
106 InitializeCriticalSection(m);
109 static inline int pthread_mutex_destroy(pthread_mutex_t *m)
111 DeleteCriticalSection(m);
114 static inline int pthread_mutex_lock(pthread_mutex_t *m)
116 EnterCriticalSection(m);
119 static inline int pthread_mutex_unlock(pthread_mutex_t *m)
121 LeaveCriticalSection(m);
125 #if _WIN32_WINNT >= 0x0600
127 typedef INIT_ONCE pthread_once_t;
128 #define PTHREAD_ONCE_INIT INIT_ONCE_STATIC_INIT
130 static av_unused int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
132 BOOL pending = FALSE;
133 InitOnceBeginInitialize(once_control, 0, &pending, NULL);
136 InitOnceComplete(once_control, 0, NULL);
140 static inline void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
142 InitializeConditionVariable(cond);
145 /* native condition variables do not destroy */
146 static inline void pthread_cond_destroy(pthread_cond_t *cond)
151 static inline void pthread_cond_broadcast(pthread_cond_t *cond)
153 WakeAllConditionVariable(cond);
156 static inline int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
158 SleepConditionVariableCS(cond, mutex, INFINITE);
162 static inline void pthread_cond_signal(pthread_cond_t *cond)
164 WakeConditionVariable(cond);
167 #else // _WIN32_WINNT < 0x0600
169 /* atomic init state of dynamically loaded functions */
170 static LONG w32thread_init_state = 0;
171 static av_unused void w32thread_init(void);
173 /* for pre-Windows 6.0 platforms, define INIT_ONCE struct,
174 * compatible to the one used in the native API */
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
181 #define PTHREAD_ONCE_INIT {0}
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);
187 /* pre-Windows 6.0 compat using a spin-lock */
188 static inline void w32thread_once_fallback(LONG volatile *state, void (*init_routine)(void))
190 switch (InterlockedCompareExchange(state, 1, 0)) {
194 InterlockedExchange(state, 2);
196 /* Another thread is running init */
205 /* Initialization complete */
211 static av_unused int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
213 w32thread_once_fallback(&w32thread_init_state, w32thread_init);
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);
221 initonce_complete(once_control, 0, NULL);
225 w32thread_once_fallback(&once_control->state, init_routine);
229 /* for pre-Windows 6.0 platforms we need to define and use our own condition
230 * variable and api */
232 typedef struct win32_cond_t {
233 pthread_mutex_t mtx_broadcast;
234 pthread_mutex_t mtx_waiter_count;
235 volatile int waiter_count;
238 volatile int is_broadcast;
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,
248 static av_unused void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
250 win32_cond_t *win32_cond = NULL;
252 w32thread_once_fallback(&w32thread_init_state, w32thread_init);
259 /* non native condition variables */
260 win32_cond = av_mallocz(sizeof(win32_cond_t));
263 cond->Ptr = win32_cond;
264 win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
265 if (!win32_cond->semaphore)
267 win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
268 if (!win32_cond->waiters_done)
271 pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
272 pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
275 static av_unused void pthread_cond_destroy(pthread_cond_t *cond)
277 win32_cond_t *win32_cond = cond->Ptr;
278 /* native condition variables do not destroy */
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);
291 static av_unused void pthread_cond_broadcast(pthread_cond_t *cond)
293 win32_cond_t *win32_cond = cond->Ptr;
296 if (cond_broadcast) {
297 cond_broadcast(cond);
301 /* non native condition variables */
302 pthread_mutex_lock(&win32_cond->mtx_broadcast);
303 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
306 if (win32_cond->waiter_count) {
307 win32_cond->is_broadcast = 1;
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;
318 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
319 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
322 static av_unused int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
324 win32_cond_t *win32_cond = cond->Ptr;
327 cond_wait(cond, mutex, INFINITE);
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);
338 // unlock the external mutex
339 pthread_mutex_unlock(mutex);
340 WaitForSingleObject(win32_cond->semaphore, INFINITE);
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);
348 SetEvent(win32_cond->waiters_done);
350 // lock the external mutex
351 return pthread_mutex_lock(mutex);
354 static av_unused void pthread_cond_signal(pthread_cond_t *cond)
356 win32_cond_t *win32_cond = cond->Ptr;
363 pthread_mutex_lock(&win32_cond->mtx_broadcast);
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);
371 ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
372 WaitForSingleObject(win32_cond->waiters_done, INFINITE);
373 ResetEvent(win32_cond->waiters_done);
376 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
380 static av_unused void w32thread_init(void)
382 #if _WIN32_WINNT < 0x0600
383 HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
384 /* if one is available, then they should all be available */
386 (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
388 (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
390 (void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
392 (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
394 (void*)GetProcAddress(kernel_dll, "InitOnceBeginInitialize");
396 (void*)GetProcAddress(kernel_dll, "InitOnceComplete");
401 #endif /* LIBAV_COMPAT_W32PTHREADS_H */