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 94static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr) 95{ 96 InitializeCriticalSection(m); 97 return 0; 98} 99static inline int pthread_mutex_destroy(pthread_mutex_t *m) 100{ 101 DeleteCriticalSection(m); 102 return 0; 103} 104static inline int pthread_mutex_lock(pthread_mutex_t *m) 105{ 106 EnterCriticalSection(m); 107 return 0; 108} 109static inline int pthread_mutex_unlock(pthread_mutex_t *m) 110{ 111 LeaveCriticalSection(m); 112 return 0; 113} 114 115/* for pre-Windows 6.0 platforms we need to define and use our own condition 116 * variable and api */ 117typedef struct { 118 pthread_mutex_t mtx_broadcast; 119 pthread_mutex_t mtx_waiter_count; 120 volatile int waiter_count; 121 HANDLE semaphore; 122 HANDLE waiters_done; 123 volatile int is_broadcast; 124} win32_cond_t; 125 126static void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr) 127{ 128 win32_cond_t *win32_cond = NULL; 129 if (cond_init) { 130 cond_init(cond); 131 return; 132 } 133 134 /* non native condition variables */ 135 win32_cond = av_mallocz(sizeof(win32_cond_t)); 136 if (!win32_cond) 137 return; 138 cond->ptr = win32_cond; 139 win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL); 140 if (!win32_cond->semaphore) 141 return; 142 win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL); 143 if (!win32_cond->waiters_done) 144 return; 145 146 pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL); 147 pthread_mutex_init(&win32_cond->mtx_broadcast, NULL); 148} 149 150static void pthread_cond_destroy(pthread_cond_t *cond) 151{ 152 win32_cond_t *win32_cond = cond->ptr; 153 /* native condition variables do not destroy */ 154 if (cond_init) 155 return; 156 157 /* non native condition variables */ 158 CloseHandle(win32_cond->semaphore); 159 CloseHandle(win32_cond->waiters_done); 160 pthread_mutex_destroy(&win32_cond->mtx_waiter_count); 161 pthread_mutex_destroy(&win32_cond->mtx_broadcast); 162 av_freep(&win32_cond); 163 cond->ptr = NULL; 164} 165 166static void pthread_cond_broadcast(pthread_cond_t *cond) 167{ 168 win32_cond_t *win32_cond = cond->ptr; 169 int have_waiter; 170 171 if (cond_broadcast) { 172 cond_broadcast(cond); 173 return; 174 } 175 176 /* non native condition variables */ 177 pthread_mutex_lock(&win32_cond->mtx_broadcast); 178 pthread_mutex_lock(&win32_cond->mtx_waiter_count); 179 have_waiter = 0; 180 181 if (win32_cond->waiter_count) { 182 win32_cond->is_broadcast = 1; 183 have_waiter = 1; 184 } 185 186 if (have_waiter) { 187 ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL); 188 pthread_mutex_unlock(&win32_cond->mtx_waiter_count); 189 WaitForSingleObject(win32_cond->waiters_done, INFINITE); 190 ResetEvent(win32_cond->waiters_done); 191 win32_cond->is_broadcast = 0; 192 } else 193 pthread_mutex_unlock(&win32_cond->mtx_waiter_count); 194 pthread_mutex_unlock(&win32_cond->mtx_broadcast); 195} 196 197static void pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex) 198{ 199 win32_cond_t *win32_cond = cond->ptr; 200 int last_waiter; 201 if (cond_wait) { 202 cond_wait(cond, mutex, INFINITE); 203 return; 204 } 205 206 /* non native condition variables */ 207 pthread_mutex_lock(&win32_cond->mtx_broadcast); 208 pthread_mutex_lock(&win32_cond->mtx_waiter_count); 209 win32_cond->waiter_count++; 210 pthread_mutex_unlock(&win32_cond->mtx_waiter_count); 211 pthread_mutex_unlock(&win32_cond->mtx_broadcast); 212 213 // unlock the external mutex 214 pthread_mutex_unlock(mutex); 215 WaitForSingleObject(win32_cond->semaphore, INFINITE); 216 217 pthread_mutex_lock(&win32_cond->mtx_waiter_count); 218 win32_cond->waiter_count--; 219 last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast; 220 pthread_mutex_unlock(&win32_cond->mtx_waiter_count); 221 222 if (last_waiter) 223 SetEvent(win32_cond->waiters_done); 224 225 // lock the external mutex 226 return pthread_mutex_lock(mutex); 227} 228 229static void pthread_cond_signal(pthread_cond_t *cond) 230{ 231 win32_cond_t *win32_cond = cond->ptr; 232 int have_waiter; 233 if (cond_signal) { 234 cond_signal(cond); 235 return; 236 } 237 238 pthread_mutex_lock(&win32_cond->mtx_broadcast); 239 240 /* non-native condition variables */ 241 pthread_mutex_lock(&win32_cond->mtx_waiter_count); 242 have_waiter = win32_cond->waiter_count; 243 pthread_mutex_unlock(&win32_cond->mtx_waiter_count); 244 245 if (have_waiter) { 246 ReleaseSemaphore(win32_cond->semaphore, 1, NULL); 247 WaitForSingleObject(win32_cond->waiters_done, INFINITE); 248 ResetEvent(win32_cond->waiters_done); 249 } 250 251 pthread_mutex_unlock(&win32_cond->mtx_broadcast); 252} 253 254static void w32thread_init(void) 255{ 256 HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll")); 257 /* if one is available, then they should all be available */ 258 cond_init = 259 (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable"); 260 cond_broadcast = 261 (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable"); 262 cond_signal = 263 (void*)GetProcAddress(kernel_dll, "WakeConditionVariable"); 264 cond_wait = 265 (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS"); 266} 267 268#endif /* AVCODEC_W32PTHREADS_H */ 269