Merge commit '8b830ee9a26d47b138f12a82085cdb372f407f1e'
[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 FFMPEG_COMPAT_W32PTHREADS_H
30 #define FFMPEG_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 #include "libavutil/attributes.h"
43 #include "libavutil/common.h"
44 #include "libavutil/internal.h"
45 #include "libavutil/mem.h"
46
47 typedef struct pthread_t {
48     void *handle;
49     void *(*func)(void* arg);
50     void *arg;
51     void *ret;
52 } pthread_t;
53
54 /* the conditional variable api for windows 6.0+ uses critical sections and
55  * not mutexes */
56 typedef CRITICAL_SECTION pthread_mutex_t;
57
58 /* This is the CONDITION_VARIABLE typedef for using Windows' native
59  * conditional variables on kernels 6.0+. */
60 #if HAVE_CONDITION_VARIABLE_PTR
61 typedef CONDITION_VARIABLE pthread_cond_t;
62 #else
63 typedef struct pthread_cond_t {
64     void *Ptr;
65 } pthread_cond_t;
66 #endif
67
68 #if _WIN32_WINNT >= 0x0600
69 #define InitializeCriticalSection(x) InitializeCriticalSectionEx(x, 0, 0)
70 #define WaitForSingleObject(a, b) WaitForSingleObjectEx(a, b, FALSE)
71 #endif
72
73 static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
74 {
75     pthread_t *h = arg;
76     h->ret = h->func(h->arg);
77     return 0;
78 }
79
80 static av_unused int pthread_create(pthread_t *thread, const void *unused_attr,
81                                     void *(*start_routine)(void*), void *arg)
82 {
83     thread->func   = start_routine;
84     thread->arg    = arg;
85     thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
86                                            0, NULL);
87     return !thread->handle;
88 }
89
90 static av_unused int pthread_join(pthread_t thread, void **value_ptr)
91 {
92     DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
93     if (ret != WAIT_OBJECT_0) {
94         if (ret == WAIT_ABANDONED)
95             return EINVAL;
96         else
97             return EDEADLK;
98     }
99     if (value_ptr)
100         *value_ptr = thread.ret;
101     CloseHandle(thread.handle);
102     return 0;
103 }
104
105 static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr)
106 {
107     InitializeCriticalSection(m);
108     return 0;
109 }
110 static inline int pthread_mutex_destroy(pthread_mutex_t *m)
111 {
112     DeleteCriticalSection(m);
113     return 0;
114 }
115 static inline int pthread_mutex_lock(pthread_mutex_t *m)
116 {
117     EnterCriticalSection(m);
118     return 0;
119 }
120 static inline int pthread_mutex_unlock(pthread_mutex_t *m)
121 {
122     LeaveCriticalSection(m);
123     return 0;
124 }
125
126 #if _WIN32_WINNT >= 0x0600
127 static inline int pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
128 {
129     InitializeConditionVariable(cond);
130     return 0;
131 }
132
133 /* native condition variables do not destroy */
134 static inline int pthread_cond_destroy(pthread_cond_t *cond)
135 {
136     return 0;
137 }
138
139 static inline int pthread_cond_broadcast(pthread_cond_t *cond)
140 {
141     WakeAllConditionVariable(cond);
142     return 0;
143 }
144
145 static inline int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
146 {
147     SleepConditionVariableCS(cond, mutex, INFINITE);
148     return 0;
149 }
150
151 static inline int pthread_cond_signal(pthread_cond_t *cond)
152 {
153     WakeConditionVariable(cond);
154     return 0;
155 }
156
157 #else // _WIN32_WINNT < 0x0600
158 /* for pre-Windows 6.0 platforms we need to define and use our own condition
159  * variable and api */
160 typedef struct  win32_cond_t {
161     pthread_mutex_t mtx_broadcast;
162     pthread_mutex_t mtx_waiter_count;
163     volatile int waiter_count;
164     HANDLE semaphore;
165     HANDLE waiters_done;
166     volatile int is_broadcast;
167 } win32_cond_t;
168
169 /* function pointers to conditional variable API on windows 6.0+ kernels */
170 static void (WINAPI *cond_broadcast)(pthread_cond_t *cond);
171 static void (WINAPI *cond_init)(pthread_cond_t *cond);
172 static void (WINAPI *cond_signal)(pthread_cond_t *cond);
173 static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex,
174                                 DWORD milliseconds);
175
176 static av_unused int pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
177 {
178     win32_cond_t *win32_cond = NULL;
179     if (cond_init) {
180         cond_init(cond);
181         return 0;
182     }
183
184     /* non native condition variables */
185     win32_cond = av_mallocz(sizeof(win32_cond_t));
186     if (!win32_cond)
187         return ENOMEM;
188     cond->Ptr = win32_cond;
189     win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
190     if (!win32_cond->semaphore)
191         return ENOMEM;
192     win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
193     if (!win32_cond->waiters_done)
194         return ENOMEM;
195
196     pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
197     pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
198     return 0;
199 }
200
201 static av_unused int pthread_cond_destroy(pthread_cond_t *cond)
202 {
203     win32_cond_t *win32_cond = cond->Ptr;
204     /* native condition variables do not destroy */
205     if (cond_init)
206         return 0;
207
208     /* non native condition variables */
209     CloseHandle(win32_cond->semaphore);
210     CloseHandle(win32_cond->waiters_done);
211     pthread_mutex_destroy(&win32_cond->mtx_waiter_count);
212     pthread_mutex_destroy(&win32_cond->mtx_broadcast);
213     av_freep(&win32_cond);
214     cond->Ptr = NULL;
215     return 0;
216 }
217
218 static av_unused int pthread_cond_broadcast(pthread_cond_t *cond)
219 {
220     win32_cond_t *win32_cond = cond->Ptr;
221     int have_waiter;
222
223     if (cond_broadcast) {
224         cond_broadcast(cond);
225         return 0;
226     }
227
228     /* non native condition variables */
229     pthread_mutex_lock(&win32_cond->mtx_broadcast);
230     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
231     have_waiter = 0;
232
233     if (win32_cond->waiter_count) {
234         win32_cond->is_broadcast = 1;
235         have_waiter = 1;
236     }
237
238     if (have_waiter) {
239         ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
240         pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
241         WaitForSingleObject(win32_cond->waiters_done, INFINITE);
242         ResetEvent(win32_cond->waiters_done);
243         win32_cond->is_broadcast = 0;
244     } else
245         pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
246     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
247     return 0;
248 }
249
250 static av_unused int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
251 {
252     win32_cond_t *win32_cond = cond->Ptr;
253     int last_waiter;
254     if (cond_wait) {
255         cond_wait(cond, mutex, INFINITE);
256         return 0;
257     }
258
259     /* non native condition variables */
260     pthread_mutex_lock(&win32_cond->mtx_broadcast);
261     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
262     win32_cond->waiter_count++;
263     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
264     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
265
266     // unlock the external mutex
267     pthread_mutex_unlock(mutex);
268     WaitForSingleObject(win32_cond->semaphore, INFINITE);
269
270     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
271     win32_cond->waiter_count--;
272     last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast;
273     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
274
275     if (last_waiter)
276         SetEvent(win32_cond->waiters_done);
277
278     // lock the external mutex
279     return pthread_mutex_lock(mutex);
280 }
281
282 static av_unused int pthread_cond_signal(pthread_cond_t *cond)
283 {
284     win32_cond_t *win32_cond = cond->Ptr;
285     int have_waiter;
286     if (cond_signal) {
287         cond_signal(cond);
288         return 0;
289     }
290
291     pthread_mutex_lock(&win32_cond->mtx_broadcast);
292
293     /* non-native condition variables */
294     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
295     have_waiter = win32_cond->waiter_count;
296     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
297
298     if (have_waiter) {
299         ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
300         WaitForSingleObject(win32_cond->waiters_done, INFINITE);
301         ResetEvent(win32_cond->waiters_done);
302     }
303
304     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
305     return 0;
306 }
307 #endif
308
309 static av_unused void w32thread_init(void)
310 {
311 #if _WIN32_WINNT < 0x0600
312     HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
313     /* if one is available, then they should all be available */
314     cond_init      =
315         (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
316     cond_broadcast =
317         (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
318     cond_signal    =
319         (void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
320     cond_wait      =
321         (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
322 #endif
323
324 }
325
326 #endif /* FFMPEG_COMPAT_W32PTHREADS_H */