ismindex: handle discontinuous streams better
[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/attributes.h"
43 #include "libavutil/internal.h"
44 #include "libavutil/mem.h"
45
46 typedef struct pthread_t {
47 void *handle;
48 void *(*func)(void* arg);
49 void *arg;
50 void *ret;
51 } pthread_t;
52
53 /* the conditional variable api for windows 6.0+ uses critical sections and
54 * not mutexes */
55 typedef CRITICAL_SECTION pthread_mutex_t;
56
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 {
61 void *ptr;
62 } pthread_cond_t;
63
64 /* function pointers to conditional variable API on windows 6.0+ kernels */
65 #if _WIN32_WINNT < 0x0600
66 static void (WINAPI *cond_broadcast)(pthread_cond_t *cond);
67 static void (WINAPI *cond_init)(pthread_cond_t *cond);
68 static void (WINAPI *cond_signal)(pthread_cond_t *cond);
69 static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex,
70 DWORD milliseconds);
71 #else
72 #define cond_init InitializeConditionVariable
73 #define cond_broadcast WakeAllConditionVariable
74 #define cond_signal WakeConditionVariable
75 #define cond_wait SleepConditionVariableCS
76
77 #define CreateEvent(a, reset, init, name) \
78 CreateEventEx(a, name, \
79 (reset ? CREATE_EVENT_MANUAL_RESET : 0) | \
80 (init ? CREATE_EVENT_INITIAL_SET : 0), \
81 EVENT_ALL_ACCESS)
82 // CreateSemaphoreExA seems to be desktop-only, but as long as we don't
83 // use named semaphores, it doesn't matter if we use the W version.
84 #define CreateSemaphore(a, b, c, d) \
85 CreateSemaphoreExW(a, b, c, d, 0, SEMAPHORE_ALL_ACCESS)
86 #define InitializeCriticalSection(x) InitializeCriticalSectionEx(x, 0, 0)
87 #define WaitForSingleObject(a, b) WaitForSingleObjectEx(a, b, FALSE)
88 #endif
89
90 static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
91 {
92 pthread_t *h = arg;
93 h->ret = h->func(h->arg);
94 return 0;
95 }
96
97 static av_unused int pthread_create(pthread_t *thread, const void *unused_attr,
98 void *(*start_routine)(void*), void *arg)
99 {
100 thread->func = start_routine;
101 thread->arg = arg;
102 thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
103 0, NULL);
104 return !thread->handle;
105 }
106
107 static av_unused void pthread_join(pthread_t thread, void **value_ptr)
108 {
109 DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
110 if (ret != WAIT_OBJECT_0)
111 return;
112 if (value_ptr)
113 *value_ptr = thread.ret;
114 CloseHandle(thread.handle);
115 }
116
117 static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr)
118 {
119 InitializeCriticalSection(m);
120 return 0;
121 }
122 static inline int pthread_mutex_destroy(pthread_mutex_t *m)
123 {
124 DeleteCriticalSection(m);
125 return 0;
126 }
127 static inline int pthread_mutex_lock(pthread_mutex_t *m)
128 {
129 EnterCriticalSection(m);
130 return 0;
131 }
132 static inline int pthread_mutex_unlock(pthread_mutex_t *m)
133 {
134 LeaveCriticalSection(m);
135 return 0;
136 }
137
138 /* for pre-Windows 6.0 platforms we need to define and use our own condition
139 * variable and api */
140 typedef struct win32_cond_t {
141 pthread_mutex_t mtx_broadcast;
142 pthread_mutex_t mtx_waiter_count;
143 volatile int waiter_count;
144 HANDLE semaphore;
145 HANDLE waiters_done;
146 volatile int is_broadcast;
147 } win32_cond_t;
148
149 static av_unused void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
150 {
151 win32_cond_t *win32_cond = NULL;
152 if (cond_init) {
153 cond_init(cond);
154 return;
155 }
156
157 /* non native condition variables */
158 win32_cond = av_mallocz(sizeof(win32_cond_t));
159 if (!win32_cond)
160 return;
161 cond->ptr = win32_cond;
162 win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
163 if (!win32_cond->semaphore)
164 return;
165 win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
166 if (!win32_cond->waiters_done)
167 return;
168
169 pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
170 pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
171 }
172
173 static av_unused void pthread_cond_destroy(pthread_cond_t *cond)
174 {
175 win32_cond_t *win32_cond = cond->ptr;
176 /* native condition variables do not destroy */
177 if (cond_init)
178 return;
179
180 /* non native condition variables */
181 CloseHandle(win32_cond->semaphore);
182 CloseHandle(win32_cond->waiters_done);
183 pthread_mutex_destroy(&win32_cond->mtx_waiter_count);
184 pthread_mutex_destroy(&win32_cond->mtx_broadcast);
185 av_freep(&win32_cond);
186 cond->ptr = NULL;
187 }
188
189 static av_unused void pthread_cond_broadcast(pthread_cond_t *cond)
190 {
191 win32_cond_t *win32_cond = cond->ptr;
192 int have_waiter;
193
194 if (cond_broadcast) {
195 cond_broadcast(cond);
196 return;
197 }
198
199 /* non native condition variables */
200 pthread_mutex_lock(&win32_cond->mtx_broadcast);
201 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
202 have_waiter = 0;
203
204 if (win32_cond->waiter_count) {
205 win32_cond->is_broadcast = 1;
206 have_waiter = 1;
207 }
208
209 if (have_waiter) {
210 ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
211 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
212 WaitForSingleObject(win32_cond->waiters_done, INFINITE);
213 ResetEvent(win32_cond->waiters_done);
214 win32_cond->is_broadcast = 0;
215 } else
216 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
217 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
218 }
219
220 static av_unused int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
221 {
222 win32_cond_t *win32_cond = cond->ptr;
223 int last_waiter;
224 if (cond_wait) {
225 cond_wait(cond, mutex, INFINITE);
226 return 0;
227 }
228
229 /* non native condition variables */
230 pthread_mutex_lock(&win32_cond->mtx_broadcast);
231 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
232 win32_cond->waiter_count++;
233 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
234 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
235
236 // unlock the external mutex
237 pthread_mutex_unlock(mutex);
238 WaitForSingleObject(win32_cond->semaphore, INFINITE);
239
240 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
241 win32_cond->waiter_count--;
242 last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast;
243 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
244
245 if (last_waiter)
246 SetEvent(win32_cond->waiters_done);
247
248 // lock the external mutex
249 return pthread_mutex_lock(mutex);
250 }
251
252 static av_unused void pthread_cond_signal(pthread_cond_t *cond)
253 {
254 win32_cond_t *win32_cond = cond->ptr;
255 int have_waiter;
256 if (cond_signal) {
257 cond_signal(cond);
258 return;
259 }
260
261 pthread_mutex_lock(&win32_cond->mtx_broadcast);
262
263 /* non-native condition variables */
264 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
265 have_waiter = win32_cond->waiter_count;
266 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
267
268 if (have_waiter) {
269 ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
270 WaitForSingleObject(win32_cond->waiters_done, INFINITE);
271 ResetEvent(win32_cond->waiters_done);
272 }
273
274 pthread_mutex_unlock(&win32_cond->mtx_broadcast);
275 }
276
277 static av_unused void w32thread_init(void)
278 {
279 #if _WIN32_WINNT < 0x0600
280 HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
281 /* if one is available, then they should all be available */
282 cond_init =
283 (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
284 cond_broadcast =
285 (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
286 cond_signal =
287 (void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
288 cond_wait =
289 (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
290 #endif
291
292 }
293
294 #endif /* LIBAV_COMPAT_W32PTHREADS_H */