Remove #undefs for formerly forbidden system functions
[libav.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 Libav.
8 *
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.
13 *
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.
18 *
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
22 */
23
24 /**
25 * @file
26 * w32threads to pthreads wrapper
27 */
28
29 #ifndef LIBAV_COMPAT_W32PTHREADS_H
30 #define LIBAV_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/internal.h"
43 #include "libavutil/mem.h"
44
45 typedef struct pthread_t {
46 void *handle;
47 void *(*func)(void* arg);
48 void *arg;
49 void *ret;
50 } pthread_t;
51
52 /* the conditional variable api for windows 6.0+ uses critical sections and
53 * not mutexes */
54 typedef CRITICAL_SECTION pthread_mutex_t;
55
56 /* This is the CONDITIONAL_VARIABLE typedef for using Window's native
57 * conditional variables on kernels 6.0+.
58 * MinGW does not currently have this typedef. */
59 typedef struct pthread_cond_t {
60 void *ptr;
61 } pthread_cond_t;
62
63 /* function pointers to conditional variable API on windows 6.0+ kernels */
64 #if _WIN32_WINNT < 0x0600
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,
69 DWORD milliseconds);
70 #else
71 #define cond_init InitializeConditionVariable
72 #define cond_broadcast WakeAllConditionVariable
73 #define cond_signal WakeConditionVariable
74 #define cond_wait SleepConditionVariableCS
75 #endif
76
77 static unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
78 {
79 pthread_t *h = arg;
80 h->ret = h->func(h->arg);
81 return 0;
82 }
83
84 static int pthread_create(pthread_t *thread, const void *unused_attr,
85 void *(*start_routine)(void*), void *arg)
86 {
87 thread->func = start_routine;
88 thread->arg = arg;
89 thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
90 0, NULL);
91 return !thread->handle;
92 }
93
94 static void pthread_join(pthread_t thread, void **value_ptr)
95 {
96 DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
97 if (ret != WAIT_OBJECT_0)
98 return;
99 if (value_ptr)
100 *value_ptr = thread.ret;
101 CloseHandle(thread.handle);
102 }
103
104 static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr)
105 {
106 InitializeCriticalSection(m);
107 return 0;
108 }
109 static inline int pthread_mutex_destroy(pthread_mutex_t *m)
110 {
111 DeleteCriticalSection(m);
112 return 0;
113 }
114 static inline int pthread_mutex_lock(pthread_mutex_t *m)
115 {
116 EnterCriticalSection(m);
117 return 0;
118 }
119 static inline int pthread_mutex_unlock(pthread_mutex_t *m)
120 {
121 LeaveCriticalSection(m);
122 return 0;
123 }
124
125 /* for pre-Windows 6.0 platforms we need to define and use our own condition
126 * variable and api */
127 typedef struct win32_cond_t {
128 pthread_mutex_t mtx_broadcast;
129 pthread_mutex_t mtx_waiter_count;
130 volatile int waiter_count;
131 HANDLE semaphore;
132 HANDLE waiters_done;
133 volatile int is_broadcast;
134 } win32_cond_t;
135
136 static void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
137 {
138 win32_cond_t *win32_cond = NULL;
139 if (cond_init) {
140 cond_init(cond);
141 return;
142 }
143
144 /* non native condition variables */
145 win32_cond = av_mallocz(sizeof(win32_cond_t));
146 if (!win32_cond)
147 return;
148 cond->ptr = win32_cond;
149 win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
150 if (!win32_cond->semaphore)
151 return;
152 win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
153 if (!win32_cond->waiters_done)
154 return;
155
156 pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
157 pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
158 }
159
160 static void pthread_cond_destroy(pthread_cond_t *cond)
161 {
162 win32_cond_t *win32_cond = cond->ptr;
163 /* native condition variables do not destroy */
164 if (cond_init)
165 return;
166
167 /* non native condition variables */
168 CloseHandle(win32_cond->semaphore);
169 CloseHandle(win32_cond->waiters_done);
170 pthread_mutex_destroy(&win32_cond->mtx_waiter_count);
171 pthread_mutex_destroy(&win32_cond->mtx_broadcast);
172 av_freep(&win32_cond);
173 cond->ptr = NULL;
174 }
175
176 static void pthread_cond_broadcast(pthread_cond_t *cond)
177 {
178 win32_cond_t *win32_cond = cond->ptr;
179 int have_waiter;
180
181 if (cond_broadcast) {
182 cond_broadcast(cond);
183 return;
184 }
185
186 /* non native condition variables */
187 pthread_mutex_lock(&win32_cond->mtx_broadcast);
188 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
189 have_waiter = 0;
190
191 if (win32_cond->waiter_count) {
192 win32_cond->is_broadcast = 1;
193 have_waiter = 1;
194 }
195
196 if (have_waiter) {
197 ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
198 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
199 WaitForSingleObject(win32_cond->waiters_done, INFINITE);
200 ResetEvent(win32_cond->waiters_done);
201 win32_cond->is_broadcast = 0;
202 } else
203 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
204 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
205 }
206
207 static int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
208 {
209 win32_cond_t *win32_cond = cond->ptr;
210 int last_waiter;
211 if (cond_wait) {
212 cond_wait(cond, mutex, INFINITE);
213 return 0;
214 }
215
216 /* non native condition variables */
217 pthread_mutex_lock(&win32_cond->mtx_broadcast);
218 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
219 win32_cond->waiter_count++;
220 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
221 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
222
223 // unlock the external mutex
224 pthread_mutex_unlock(mutex);
225 WaitForSingleObject(win32_cond->semaphore, INFINITE);
226
227 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
228 win32_cond->waiter_count--;
229 last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast;
230 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
231
232 if (last_waiter)
233 SetEvent(win32_cond->waiters_done);
234
235 // lock the external mutex
236 return pthread_mutex_lock(mutex);
237 }
238
239 static void pthread_cond_signal(pthread_cond_t *cond)
240 {
241 win32_cond_t *win32_cond = cond->ptr;
242 int have_waiter;
243 if (cond_signal) {
244 cond_signal(cond);
245 return;
246 }
247
248 pthread_mutex_lock(&win32_cond->mtx_broadcast);
249
250 /* non-native condition variables */
251 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
252 have_waiter = win32_cond->waiter_count;
253 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
254
255 if (have_waiter) {
256 ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
257 WaitForSingleObject(win32_cond->waiters_done, INFINITE);
258 ResetEvent(win32_cond->waiters_done);
259 }
260
261 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
262 }
263
264 static void w32thread_init(void)
265 {
266 #if _WIN32_WINNT < 0x0600
267 HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
268 /* if one is available, then they should all be available */
269 cond_init =
270 (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
271 cond_broadcast =
272 (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
273 cond_signal =
274 (void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
275 cond_wait =
276 (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
277 #endif
278
279 }
280
281 #endif /* LIBAV_COMPAT_W32PTHREADS_H */