compat/atomics: rename header guards
[ffmpeg.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 FFmpeg.
8  *
9  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 COMPAT_W32PTHREADS_H
30 #define 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/common.h"
49 #include "libavutil/internal.h"
50 #include "libavutil/mem.h"
51
52 typedef struct pthread_t {
53     void *handle;
54     void *(*func)(void* arg);
55     void *arg;
56     void *ret;
57 } pthread_t;
58
59 /* the conditional variable api for windows 6.0+ uses critical sections and
60  * not mutexes */
61 typedef CRITICAL_SECTION pthread_mutex_t;
62
63 /* This is the CONDITION_VARIABLE typedef for using Windows' native
64  * conditional variables on kernels 6.0+. */
65 #if HAVE_CONDITION_VARIABLE_PTR
66 typedef CONDITION_VARIABLE pthread_cond_t;
67 #else
68 typedef struct pthread_cond_t {
69     void *Ptr;
70 } pthread_cond_t;
71 #endif
72
73 #if _WIN32_WINNT >= 0x0600
74 #define InitializeCriticalSection(x) InitializeCriticalSectionEx(x, 0, 0)
75 #define WaitForSingleObject(a, b) WaitForSingleObjectEx(a, b, FALSE)
76 #endif
77
78 static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
79 {
80     pthread_t *h = arg;
81     h->ret = h->func(h->arg);
82     return 0;
83 }
84
85 static av_unused int pthread_create(pthread_t *thread, const void *unused_attr,
86                                     void *(*start_routine)(void*), void *arg)
87 {
88     thread->func   = start_routine;
89     thread->arg    = arg;
90 #if HAVE_WINRT
91     thread->handle = (void*)CreateThread(NULL, 0, win32thread_worker, thread,
92                                            0, NULL);
93 #else
94     thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
95                                            0, NULL);
96 #endif
97     return !thread->handle;
98 }
99
100 static av_unused int pthread_join(pthread_t thread, void **value_ptr)
101 {
102     DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
103     if (ret != WAIT_OBJECT_0) {
104         if (ret == WAIT_ABANDONED)
105             return EINVAL;
106         else
107             return EDEADLK;
108     }
109     if (value_ptr)
110         *value_ptr = thread.ret;
111     CloseHandle(thread.handle);
112     return 0;
113 }
114
115 static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr)
116 {
117     InitializeCriticalSection(m);
118     return 0;
119 }
120 static inline int pthread_mutex_destroy(pthread_mutex_t *m)
121 {
122     DeleteCriticalSection(m);
123     return 0;
124 }
125 static inline int pthread_mutex_lock(pthread_mutex_t *m)
126 {
127     EnterCriticalSection(m);
128     return 0;
129 }
130 static inline int pthread_mutex_unlock(pthread_mutex_t *m)
131 {
132     LeaveCriticalSection(m);
133     return 0;
134 }
135
136 #if _WIN32_WINNT >= 0x0600
137 typedef INIT_ONCE pthread_once_t;
138 #define PTHREAD_ONCE_INIT INIT_ONCE_STATIC_INIT
139
140 static av_unused int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
141 {
142     BOOL pending = FALSE;
143     InitOnceBeginInitialize(once_control, 0, &pending, NULL);
144     if (pending)
145         init_routine();
146     InitOnceComplete(once_control, 0, NULL);
147     return 0;
148 }
149
150 static inline int pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
151 {
152     InitializeConditionVariable(cond);
153     return 0;
154 }
155
156 /* native condition variables do not destroy */
157 static inline int pthread_cond_destroy(pthread_cond_t *cond)
158 {
159     return 0;
160 }
161
162 static inline int pthread_cond_broadcast(pthread_cond_t *cond)
163 {
164     WakeAllConditionVariable(cond);
165     return 0;
166 }
167
168 static inline int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
169 {
170     SleepConditionVariableCS(cond, mutex, INFINITE);
171     return 0;
172 }
173
174 static inline int pthread_cond_signal(pthread_cond_t *cond)
175 {
176     WakeConditionVariable(cond);
177     return 0;
178 }
179
180 #else // _WIN32_WINNT < 0x0600
181
182 /* atomic init state of dynamically loaded functions */
183 static LONG w32thread_init_state = 0;
184 static av_unused void w32thread_init(void);
185
186 /* for pre-Windows 6.0 platforms, define INIT_ONCE struct,
187  * compatible to the one used in the native API */
188
189 typedef union pthread_once_t  {
190     void * Ptr;    ///< For the Windows 6.0+ native functions
191     LONG state;    ///< For the pre-Windows 6.0 compat code
192 } pthread_once_t;
193
194 #define PTHREAD_ONCE_INIT {0}
195
196 /* function pointers to init once API on windows 6.0+ kernels */
197 static BOOL (WINAPI *initonce_begin)(pthread_once_t *lpInitOnce, DWORD dwFlags, BOOL *fPending, void **lpContext);
198 static BOOL (WINAPI *initonce_complete)(pthread_once_t *lpInitOnce, DWORD dwFlags, void *lpContext);
199
200 /* pre-Windows 6.0 compat using a spin-lock */
201 static inline void w32thread_once_fallback(LONG volatile *state, void (*init_routine)(void))
202 {
203     switch (InterlockedCompareExchange(state, 1, 0)) {
204     /* Initial run */
205     case 0:
206         init_routine();
207         InterlockedExchange(state, 2);
208         break;
209     /* Another thread is running init */
210     case 1:
211         while (1) {
212             MemoryBarrier();
213             if (*state == 2)
214                 break;
215             Sleep(0);
216         }
217         break;
218     /* Initialization complete */
219     case 2:
220         break;
221     }
222 }
223
224 static av_unused int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
225 {
226     w32thread_once_fallback(&w32thread_init_state, w32thread_init);
227
228     /* Use native functions on Windows 6.0+ */
229     if (initonce_begin && initonce_complete) {
230         BOOL pending = FALSE;
231         initonce_begin(once_control, 0, &pending, NULL);
232         if (pending)
233             init_routine();
234         initonce_complete(once_control, 0, NULL);
235         return 0;
236     }
237
238     w32thread_once_fallback(&once_control->state, init_routine);
239     return 0;
240 }
241
242 /* for pre-Windows 6.0 platforms we need to define and use our own condition
243  * variable and api */
244
245 typedef struct  win32_cond_t {
246     pthread_mutex_t mtx_broadcast;
247     pthread_mutex_t mtx_waiter_count;
248     volatile int waiter_count;
249     HANDLE semaphore;
250     HANDLE waiters_done;
251     volatile int is_broadcast;
252 } win32_cond_t;
253
254 /* function pointers to conditional variable API on windows 6.0+ kernels */
255 static void (WINAPI *cond_broadcast)(pthread_cond_t *cond);
256 static void (WINAPI *cond_init)(pthread_cond_t *cond);
257 static void (WINAPI *cond_signal)(pthread_cond_t *cond);
258 static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex,
259                                 DWORD milliseconds);
260
261 static av_unused int pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
262 {
263     win32_cond_t *win32_cond = NULL;
264
265     w32thread_once_fallback(&w32thread_init_state, w32thread_init);
266
267     if (cond_init) {
268         cond_init(cond);
269         return 0;
270     }
271
272     /* non native condition variables */
273     win32_cond = av_mallocz(sizeof(win32_cond_t));
274     if (!win32_cond)
275         return ENOMEM;
276     cond->Ptr = win32_cond;
277     win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
278     if (!win32_cond->semaphore)
279         return ENOMEM;
280     win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
281     if (!win32_cond->waiters_done)
282         return ENOMEM;
283
284     pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
285     pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
286     return 0;
287 }
288
289 static av_unused int pthread_cond_destroy(pthread_cond_t *cond)
290 {
291     win32_cond_t *win32_cond = cond->Ptr;
292     /* native condition variables do not destroy */
293     if (cond_init)
294         return 0;
295
296     /* non native condition variables */
297     CloseHandle(win32_cond->semaphore);
298     CloseHandle(win32_cond->waiters_done);
299     pthread_mutex_destroy(&win32_cond->mtx_waiter_count);
300     pthread_mutex_destroy(&win32_cond->mtx_broadcast);
301     av_freep(&win32_cond);
302     cond->Ptr = NULL;
303     return 0;
304 }
305
306 static av_unused int pthread_cond_broadcast(pthread_cond_t *cond)
307 {
308     win32_cond_t *win32_cond = cond->Ptr;
309     int have_waiter;
310
311     if (cond_broadcast) {
312         cond_broadcast(cond);
313         return 0;
314     }
315
316     /* non native condition variables */
317     pthread_mutex_lock(&win32_cond->mtx_broadcast);
318     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
319     have_waiter = 0;
320
321     if (win32_cond->waiter_count) {
322         win32_cond->is_broadcast = 1;
323         have_waiter = 1;
324     }
325
326     if (have_waiter) {
327         ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
328         pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
329         WaitForSingleObject(win32_cond->waiters_done, INFINITE);
330         ResetEvent(win32_cond->waiters_done);
331         win32_cond->is_broadcast = 0;
332     } else
333         pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
334     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
335     return 0;
336 }
337
338 static av_unused int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
339 {
340     win32_cond_t *win32_cond = cond->Ptr;
341     int last_waiter;
342     if (cond_wait) {
343         cond_wait(cond, mutex, INFINITE);
344         return 0;
345     }
346
347     /* non native condition variables */
348     pthread_mutex_lock(&win32_cond->mtx_broadcast);
349     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
350     win32_cond->waiter_count++;
351     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
352     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
353
354     // unlock the external mutex
355     pthread_mutex_unlock(mutex);
356     WaitForSingleObject(win32_cond->semaphore, INFINITE);
357
358     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
359     win32_cond->waiter_count--;
360     last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast;
361     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
362
363     if (last_waiter)
364         SetEvent(win32_cond->waiters_done);
365
366     // lock the external mutex
367     return pthread_mutex_lock(mutex);
368 }
369
370 static av_unused int pthread_cond_signal(pthread_cond_t *cond)
371 {
372     win32_cond_t *win32_cond = cond->Ptr;
373     int have_waiter;
374     if (cond_signal) {
375         cond_signal(cond);
376         return 0;
377     }
378
379     pthread_mutex_lock(&win32_cond->mtx_broadcast);
380
381     /* non-native condition variables */
382     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
383     have_waiter = win32_cond->waiter_count;
384     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
385
386     if (have_waiter) {
387         ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
388         WaitForSingleObject(win32_cond->waiters_done, INFINITE);
389         ResetEvent(win32_cond->waiters_done);
390     }
391
392     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
393     return 0;
394 }
395 #endif
396
397 static av_unused void w32thread_init(void)
398 {
399 #if _WIN32_WINNT < 0x0600
400     HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
401     /* if one is available, then they should all be available */
402     cond_init      =
403         (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
404     cond_broadcast =
405         (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
406     cond_signal    =
407         (void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
408     cond_wait      =
409         (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
410     initonce_begin =
411         (void*)GetProcAddress(kernel_dll, "InitOnceBeginInitialize");
412     initonce_complete =
413         (void*)GetProcAddress(kernel_dll, "InitOnceComplete");
414 #endif
415
416 }
417
418 #endif /* COMPAT_W32PTHREADS_H */