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 FFmpeg.
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.
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.
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
26 * w32threads to pthreads wrapper
29 #ifndef FFMPEG_COMPAT_W32PTHREADS_H
30 #define FFMPEG_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 #include "libavutil/attributes.h"
43 #include "libavutil/common.h"
44 #include "libavutil/internal.h"
45 #include "libavutil/mem.h"
47 typedef struct pthread_t {
49 void *(*func)(void* arg);
54 /* the conditional variable api for windows 6.0+ uses critical sections and
56 typedef CRITICAL_SECTION pthread_mutex_t;
58 /* This is the CONDITIONAL_VARIABLE typedef for using Window's native
59 * conditional variables on kernels 6.0+.
60 * MinGW does not currently have this typedef. */
61 typedef struct pthread_cond_t {
65 /* function pointers to conditional variable API on windows 6.0+ kernels */
66 #if _WIN32_WINNT < 0x0600
67 static void (WINAPI *cond_broadcast)(pthread_cond_t *cond);
68 static void (WINAPI *cond_init)(pthread_cond_t *cond);
69 static void (WINAPI *cond_signal)(pthread_cond_t *cond);
70 static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex,
73 #define cond_init InitializeConditionVariable
74 #define cond_broadcast WakeAllConditionVariable
75 #define cond_signal WakeConditionVariable
76 #define cond_wait SleepConditionVariableCS
78 #define CreateEvent(a, reset, init, name) \
79 CreateEventEx(a, name, \
80 (reset ? CREATE_EVENT_MANUAL_RESET : 0) | \
81 (init ? CREATE_EVENT_INITIAL_SET : 0), \
83 // CreateSemaphoreExA seems to be desktop-only, but as long as we don't
84 // use named semaphores, it doesn't matter if we use the W version.
85 #define CreateSemaphore(a, b, c, d) \
86 CreateSemaphoreExW(a, b, c, d, 0, SEMAPHORE_ALL_ACCESS)
87 #define InitializeCriticalSection(x) InitializeCriticalSectionEx(x, 0, 0)
88 #define WaitForSingleObject(a, b) WaitForSingleObjectEx(a, b, FALSE)
91 static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
94 h->ret = h->func(h->arg);
98 static av_unused int pthread_create(pthread_t *thread, const void *unused_attr,
99 void *(*start_routine)(void*), void *arg)
101 thread->func = start_routine;
103 thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
105 return !thread->handle;
108 static av_unused void pthread_join(pthread_t thread, void **value_ptr)
110 DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
111 if (ret != WAIT_OBJECT_0)
114 *value_ptr = thread.ret;
115 CloseHandle(thread.handle);
118 static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr)
120 InitializeCriticalSection(m);
123 static inline int pthread_mutex_destroy(pthread_mutex_t *m)
125 DeleteCriticalSection(m);
128 static inline int pthread_mutex_lock(pthread_mutex_t *m)
130 EnterCriticalSection(m);
133 static inline int pthread_mutex_unlock(pthread_mutex_t *m)
135 LeaveCriticalSection(m);
139 /* for pre-Windows 6.0 platforms we need to define and use our own condition
140 * variable and api */
141 typedef struct win32_cond_t {
142 pthread_mutex_t mtx_broadcast;
143 pthread_mutex_t mtx_waiter_count;
144 volatile int waiter_count;
147 volatile int is_broadcast;
150 static av_unused int pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
152 win32_cond_t *win32_cond = NULL;
158 /* non native condition variables */
159 win32_cond = av_mallocz(sizeof(win32_cond_t));
162 cond->ptr = win32_cond;
163 win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
164 if (!win32_cond->semaphore)
166 win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
167 if (!win32_cond->waiters_done)
170 pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
171 pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
175 static av_unused void pthread_cond_destroy(pthread_cond_t *cond)
177 win32_cond_t *win32_cond = cond->ptr;
178 /* native condition variables do not destroy */
182 /* non native condition variables */
183 CloseHandle(win32_cond->semaphore);
184 CloseHandle(win32_cond->waiters_done);
185 pthread_mutex_destroy(&win32_cond->mtx_waiter_count);
186 pthread_mutex_destroy(&win32_cond->mtx_broadcast);
187 av_freep(&win32_cond);
191 static av_unused void pthread_cond_broadcast(pthread_cond_t *cond)
193 win32_cond_t *win32_cond = cond->ptr;
196 if (cond_broadcast) {
197 cond_broadcast(cond);
201 /* non native condition variables */
202 pthread_mutex_lock(&win32_cond->mtx_broadcast);
203 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
206 if (win32_cond->waiter_count) {
207 win32_cond->is_broadcast = 1;
212 ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
213 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
214 WaitForSingleObject(win32_cond->waiters_done, INFINITE);
215 ResetEvent(win32_cond->waiters_done);
216 win32_cond->is_broadcast = 0;
218 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
219 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
222 static av_unused int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
224 win32_cond_t *win32_cond = cond->ptr;
227 cond_wait(cond, mutex, INFINITE);
231 /* non native condition variables */
232 pthread_mutex_lock(&win32_cond->mtx_broadcast);
233 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
234 win32_cond->waiter_count++;
235 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
236 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
238 // unlock the external mutex
239 pthread_mutex_unlock(mutex);
240 WaitForSingleObject(win32_cond->semaphore, INFINITE);
242 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
243 win32_cond->waiter_count--;
244 last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast;
245 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
248 SetEvent(win32_cond->waiters_done);
250 // lock the external mutex
251 return pthread_mutex_lock(mutex);
254 static av_unused void pthread_cond_signal(pthread_cond_t *cond)
256 win32_cond_t *win32_cond = cond->ptr;
263 pthread_mutex_lock(&win32_cond->mtx_broadcast);
265 /* non-native condition variables */
266 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
267 have_waiter = win32_cond->waiter_count;
268 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
271 ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
272 WaitForSingleObject(win32_cond->waiters_done, INFINITE);
273 ResetEvent(win32_cond->waiters_done);
276 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
279 static av_unused void w32thread_init(void)
281 #if _WIN32_WINNT < 0x0600
282 HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
283 /* if one is available, then they should all be available */
285 (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
287 (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
289 (void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
291 (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
296 #endif /* FFMPEG_COMPAT_W32PTHREADS_H */