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 AVCODEC_W32PTHREADS_H
30 #define AVCODEC_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/common.h"
43 #include "libavutil/internal.h"
44 #include "libavutil/mem.h"
46 typedef struct pthread_t {
48 void *(*func)(void* arg);
53 /* the conditional variable api for windows 6.0+ uses critical sections and
55 typedef CRITICAL_SECTION pthread_mutex_t;
57 /* This is the CONDITIONAL_VARIABLE typedef for using Window's native
58 * conditional variables on kernels 6.0+.
59 * MinGW does not currently have this typedef. */
60 typedef struct pthread_cond_t {
64 /* function pointers to conditional variable API on windows 6.0+ kernels */
65 static void (WINAPI *cond_broadcast)(pthread_cond_t *cond);
66 static void (WINAPI *cond_init)(pthread_cond_t *cond);
67 static void (WINAPI *cond_signal)(pthread_cond_t *cond);
68 static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex,
71 static unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
74 h->ret = h->func(h->arg);
78 static int pthread_create(pthread_t *thread, const void *unused_attr,
79 void *(*start_routine)(void*), void *arg)
81 thread->func = start_routine;
83 thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
85 return !thread->handle;
88 static void pthread_join(pthread_t thread, void **value_ptr)
90 DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
91 if (ret != WAIT_OBJECT_0)
94 *value_ptr = thread.ret;
95 CloseHandle(thread.handle);
98 static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr)
100 InitializeCriticalSection(m);
103 static inline int pthread_mutex_destroy(pthread_mutex_t *m)
105 DeleteCriticalSection(m);
108 static inline int pthread_mutex_lock(pthread_mutex_t *m)
110 EnterCriticalSection(m);
113 static inline int pthread_mutex_unlock(pthread_mutex_t *m)
115 LeaveCriticalSection(m);
119 /* for pre-Windows 6.0 platforms we need to define and use our own condition
120 * variable and api */
121 typedef struct win32_cond_t {
122 pthread_mutex_t mtx_broadcast;
123 pthread_mutex_t mtx_waiter_count;
124 volatile int waiter_count;
127 volatile int is_broadcast;
130 static void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
132 win32_cond_t *win32_cond = NULL;
138 /* non native condition variables */
139 win32_cond = av_mallocz(sizeof(win32_cond_t));
142 cond->ptr = win32_cond;
143 win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
144 if (!win32_cond->semaphore)
146 win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
147 if (!win32_cond->waiters_done)
150 pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
151 pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
154 static void pthread_cond_destroy(pthread_cond_t *cond)
156 win32_cond_t *win32_cond = cond->ptr;
157 /* native condition variables do not destroy */
161 /* non native condition variables */
162 CloseHandle(win32_cond->semaphore);
163 CloseHandle(win32_cond->waiters_done);
164 pthread_mutex_destroy(&win32_cond->mtx_waiter_count);
165 pthread_mutex_destroy(&win32_cond->mtx_broadcast);
166 av_freep(&win32_cond);
170 static void pthread_cond_broadcast(pthread_cond_t *cond)
172 win32_cond_t *win32_cond = cond->ptr;
175 if (cond_broadcast) {
176 cond_broadcast(cond);
180 /* non native condition variables */
181 pthread_mutex_lock(&win32_cond->mtx_broadcast);
182 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
185 if (win32_cond->waiter_count) {
186 win32_cond->is_broadcast = 1;
191 ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
192 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
193 WaitForSingleObject(win32_cond->waiters_done, INFINITE);
194 ResetEvent(win32_cond->waiters_done);
195 win32_cond->is_broadcast = 0;
197 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
198 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
201 static int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
203 win32_cond_t *win32_cond = cond->ptr;
206 cond_wait(cond, mutex, INFINITE);
210 /* non native condition variables */
211 pthread_mutex_lock(&win32_cond->mtx_broadcast);
212 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
213 win32_cond->waiter_count++;
214 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
215 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
217 // unlock the external mutex
218 pthread_mutex_unlock(mutex);
219 WaitForSingleObject(win32_cond->semaphore, INFINITE);
221 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
222 win32_cond->waiter_count--;
223 last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast;
224 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
227 SetEvent(win32_cond->waiters_done);
229 // lock the external mutex
230 return pthread_mutex_lock(mutex);
233 static void pthread_cond_signal(pthread_cond_t *cond)
235 win32_cond_t *win32_cond = cond->ptr;
242 pthread_mutex_lock(&win32_cond->mtx_broadcast);
244 /* non-native condition variables */
245 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
246 have_waiter = win32_cond->waiter_count;
247 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
250 ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
251 WaitForSingleObject(win32_cond->waiters_done, INFINITE);
252 ResetEvent(win32_cond->waiters_done);
255 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
258 static void w32thread_init(void)
260 HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
261 /* if one is available, then they should all be available */
263 (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
265 (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
267 (void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
269 (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
272 #endif /* AVCODEC_W32PTHREADS_H */