/* * Copyright (C) 2010-2011 x264 project * * Authors: Steven Walters <kemuri9@gmail.com> * Pegasys Inc. <http://www.pegasys-inc.com> * * This file is part of Libav. * * Libav is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * Libav is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * w32threads to pthreads wrapper */ #ifndef AVCODEC_W32PTHREADS_H #define AVCODEC_W32PTHREADS_H /* Build up a pthread-like API using underlying Windows API. Have only static * methods so as to not conflict with a potentially linked in pthread-win32 * library. * As most functions here are used without checking return values, * only implement return values as necessary. */ #define WIN32_LEAN_AND_MEAN #include <windows.h> #include <process.h> typedef struct { void *handle; void *(*func)(void* arg); void *arg; void *ret; } pthread_t; /* the conditional variable api for windows 6.0+ uses critical sections and * not mutexes */ typedef CRITICAL_SECTION pthread_mutex_t; /* This is the CONDITIONAL_VARIABLE typedef for using Window's native * conditional variables on kernels 6.0+. * MinGW does not currently have this typedef. */ typedef struct { void *ptr; } pthread_cond_t; /* function pointers to conditional variable API on windows 6.0+ kernels */ static void (WINAPI *cond_broadcast)(pthread_cond_t *cond); static void (WINAPI *cond_init)(pthread_cond_t *cond); static void (WINAPI *cond_signal)(pthread_cond_t *cond); static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex, DWORD milliseconds); static unsigned __stdcall attribute_align_arg win32thread_worker(void *arg) { pthread_t *h = arg; h->ret = h->func(h->arg); return 0; } static int pthread_create(pthread_t *thread, const void *unused_attr, void *(*start_routine)(void*), void *arg) { thread->func = start_routine; thread->arg = arg; thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread, 0, NULL); return !thread->handle; } static void pthread_join(pthread_t thread, void **value_ptr) { DWORD ret = WaitForSingleObject(thread.handle, INFINITE); if (ret != WAIT_OBJECT_0) return; if (value_ptr) *value_ptr = thread.ret; CloseHandle(thread.handle); } static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr) { InitializeCriticalSection(m); return 0; } static inline int pthread_mutex_destroy(pthread_mutex_t *m) { DeleteCriticalSection(m); return 0; } static inline int pthread_mutex_lock(pthread_mutex_t *m) { EnterCriticalSection(m); return 0; } static inline int pthread_mutex_unlock(pthread_mutex_t *m) { LeaveCriticalSection(m); return 0; } /* for pre-Windows 6.0 platforms we need to define and use our own condition * variable and api */ typedef struct { pthread_mutex_t mtx_broadcast; pthread_mutex_t mtx_waiter_count; volatile int waiter_count; HANDLE semaphore; HANDLE waiters_done; volatile int is_broadcast; } win32_cond_t; static void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr) { win32_cond_t *win32_cond = NULL; if (cond_init) { cond_init(cond); return; } /* non native condition variables */ win32_cond = av_mallocz(sizeof(win32_cond_t)); if (!win32_cond) return; cond->ptr = win32_cond; win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL); if (!win32_cond->semaphore) return; win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL); if (!win32_cond->waiters_done) return; pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL); pthread_mutex_init(&win32_cond->mtx_broadcast, NULL); } static void pthread_cond_destroy(pthread_cond_t *cond) { win32_cond_t *win32_cond = cond->ptr; /* native condition variables do not destroy */ if (cond_init) return; /* non native condition variables */ CloseHandle(win32_cond->semaphore); CloseHandle(win32_cond->waiters_done); pthread_mutex_destroy(&win32_cond->mtx_waiter_count); pthread_mutex_destroy(&win32_cond->mtx_broadcast); av_freep(&win32_cond); cond->ptr = NULL; } static void pthread_cond_broadcast(pthread_cond_t *cond) { win32_cond_t *win32_cond = cond->ptr; int have_waiter; if (cond_broadcast) { cond_broadcast(cond); return; } /* non native condition variables */ pthread_mutex_lock(&win32_cond->mtx_broadcast); pthread_mutex_lock(&win32_cond->mtx_waiter_count); have_waiter = 0; if (win32_cond->waiter_count) { win32_cond->is_broadcast = 1; have_waiter = 1; } if (have_waiter) { ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL); pthread_mutex_unlock(&win32_cond->mtx_waiter_count); WaitForSingleObject(win32_cond->waiters_done, INFINITE); ResetEvent(win32_cond->waiters_done); win32_cond->is_broadcast = 0; } else pthread_mutex_unlock(&win32_cond->mtx_waiter_count); pthread_mutex_unlock(&win32_cond->mtx_broadcast); } static int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex) { win32_cond_t *win32_cond = cond->ptr; int last_waiter; if (cond_wait) { cond_wait(cond, mutex, INFINITE); return 0; } /* non native condition variables */ pthread_mutex_lock(&win32_cond->mtx_broadcast); pthread_mutex_lock(&win32_cond->mtx_waiter_count); win32_cond->waiter_count++; pthread_mutex_unlock(&win32_cond->mtx_waiter_count); pthread_mutex_unlock(&win32_cond->mtx_broadcast); // unlock the external mutex pthread_mutex_unlock(mutex); WaitForSingleObject(win32_cond->semaphore, INFINITE); pthread_mutex_lock(&win32_cond->mtx_waiter_count); win32_cond->waiter_count--; last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast; pthread_mutex_unlock(&win32_cond->mtx_waiter_count); if (last_waiter) SetEvent(win32_cond->waiters_done); // lock the external mutex return pthread_mutex_lock(mutex); } static void pthread_cond_signal(pthread_cond_t *cond) { win32_cond_t *win32_cond = cond->ptr; int have_waiter; if (cond_signal) { cond_signal(cond); return; } pthread_mutex_lock(&win32_cond->mtx_broadcast); /* non-native condition variables */ pthread_mutex_lock(&win32_cond->mtx_waiter_count); have_waiter = win32_cond->waiter_count; pthread_mutex_unlock(&win32_cond->mtx_waiter_count); if (have_waiter) { ReleaseSemaphore(win32_cond->semaphore, 1, NULL); WaitForSingleObject(win32_cond->waiters_done, INFINITE); ResetEvent(win32_cond->waiters_done); } pthread_mutex_unlock(&win32_cond->mtx_broadcast); } static void w32thread_init(void) { HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll")); /* if one is available, then they should all be available */ cond_init = (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable"); cond_broadcast = (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable"); cond_signal = (void*)GetProcAddress(kernel_dll, "WakeConditionVariable"); cond_wait = (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS"); } #endif /* AVCODEC_W32PTHREADS_H */