configure: Allow linking to the gnutls library
[libav.git] / libavcodec / w32pthreads.h
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27237d52
SW
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 AVCODEC_W32PTHREADS_H
30#define AVCODEC_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
42typedef struct {
43 void *handle;
44 void *(*func)(void* arg);
45 void *arg;
46 void *ret;
47} pthread_t;
48
49/* the conditional variable api for windows 6.0+ uses critical sections and
50 * not mutexes */
51typedef CRITICAL_SECTION pthread_mutex_t;
52
53/* This is the CONDITIONAL_VARIABLE typedef for using Window's native
54 * conditional variables on kernels 6.0+.
55 * MinGW does not currently have this typedef. */
56typedef struct {
57 void *ptr;
58} pthread_cond_t;
59
60/* function pointers to conditional variable API on windows 6.0+ kernels */
61static void (WINAPI *cond_broadcast)(pthread_cond_t *cond);
62static void (WINAPI *cond_init)(pthread_cond_t *cond);
63static void (WINAPI *cond_signal)(pthread_cond_t *cond);
64static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex,
65 DWORD milliseconds);
66
67static unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
68{
69 pthread_t *h = arg;
70 h->ret = h->func(h->arg);
71 return 0;
72}
73
74static int pthread_create(pthread_t *thread, const void *unused_attr,
75 void *(*start_routine)(void*), void *arg)
76{
77 thread->func = start_routine;
78 thread->arg = arg;
79 thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
80 0, NULL);
81 return !thread->handle;
82}
83
84static void pthread_join(pthread_t thread, void **value_ptr)
85{
86 DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
87 if (ret != WAIT_OBJECT_0)
88 return;
89 if (value_ptr)
90 *value_ptr = thread.ret;
91 CloseHandle(thread.handle);
92}
93
94#define pthread_mutex_init(m, a) InitializeCriticalSection(m)
95#define pthread_mutex_destroy(m) DeleteCriticalSection(m)
96#define pthread_mutex_lock(m) EnterCriticalSection(m)
97#define pthread_mutex_unlock(m) LeaveCriticalSection(m)
98
99/* for pre-Windows 6.0 platforms we need to define and use our own condition
100 * variable and api */
101typedef struct {
102 pthread_mutex_t mtx_waiter_count;
103 volatile int waiter_count;
104 HANDLE semaphore;
105} win32_cond_t;
106
107static void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
108{
109 win32_cond_t *win32_cond = NULL;
110 if (cond_init) {
111 cond_init(cond);
112 return;
113 }
114
115 /* non native condition variables */
116 win32_cond = av_mallocz(sizeof(win32_cond_t));
117 if (!win32_cond)
118 return;
119 cond->ptr = win32_cond;
120 win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
121 if (!win32_cond->semaphore)
122 return;
123
124 pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
125}
126
127static void pthread_cond_destroy(pthread_cond_t *cond)
128{
129 win32_cond_t *win32_cond = cond->ptr;
130 /* native condition variables do not destroy */
131 if (cond_init)
132 return;
133
134 /* non native condition variables */
135 CloseHandle(win32_cond->semaphore);
136 pthread_mutex_destroy(&win32_cond->mtx_waiter_count);
137 av_freep(&win32_cond);
138 cond->ptr = NULL;
139}
140
141static void pthread_cond_broadcast(pthread_cond_t *cond)
142{
143 win32_cond_t *win32_cond = cond->ptr;
144 if (cond_broadcast) {
145 cond_broadcast(cond);
146 return;
147 }
148
149 /* non native condition variables */
150 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
151 if (win32_cond->waiter_count) {
152 ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
153 win32_cond->waiter_count = 0;
154 }
155 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
156}
157
158static void pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
159{
160 win32_cond_t *win32_cond = cond->ptr;
161 if (cond_wait) {
162 cond_wait(cond, mutex, INFINITE);
163 return;
164 }
165
166 /* non native condition variables */
167 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
168 win32_cond->waiter_count++;
169 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
170
171 pthread_mutex_unlock(mutex);
172 WaitForSingleObject(win32_cond->semaphore, INFINITE);
173 pthread_mutex_lock(mutex);
174}
175
176static void pthread_cond_signal(pthread_cond_t *cond)
177{
178 win32_cond_t *win32_cond = cond->ptr;
179 if (cond_signal) {
180 cond_signal(cond);
181 return;
182 }
183
184 /* non-native condition variables */
185 pthread_mutex_lock(&win32_cond->mtx_waiter_count);
186 if (win32_cond->waiter_count) {
187 ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
188 win32_cond->waiter_count--;
189 }
190 pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
191}
192
193static void w32thread_init(void)
194{
195 HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
196 /* if one is available, then they should all be available */
197 cond_init =
198 (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
199 cond_broadcast =
200 (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
201 cond_signal =
202 (void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
203 cond_wait =
204 (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
205}
206
207#endif /* AVCODEC_W32PTHREADS_H */