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* Copyright (C) 2010-2011 x264 project
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* Authors: Steven Walters <kemuri9@gmail.com>
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* Pegasys Inc. <http://www.pegasys-inc.com>
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* This file is part of Libav.
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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* w32threads to pthreads wrapper
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#ifndef AVCODEC_W32PTHREADS_H
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#define AVCODEC_W32PTHREADS_H
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/* Build up a pthread-like API using underlying Windows API. Have only static
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* methods so as to not conflict with a potentially linked in pthread-win32
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* As most functions here are used without checking return values,
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* only implement return values as necessary. */
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#define WIN32_LEAN_AND_MEAN
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#include "libavutil/common.h"
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#include "libavutil/internal.h"
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#include "libavutil/mem.h"
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typedef struct pthread_t {
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void *(*func)(void* arg);
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/* the conditional variable api for windows 6.0+ uses critical sections and
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typedef CRITICAL_SECTION pthread_mutex_t;
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/* This is the CONDITIONAL_VARIABLE typedef for using Window's native
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* conditional variables on kernels 6.0+.
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* MinGW does not currently have this typedef. */
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typedef struct pthread_cond_t {
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/* function pointers to conditional variable API on windows 6.0+ kernels */
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static void (WINAPI *cond_broadcast)(pthread_cond_t *cond);
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static void (WINAPI *cond_init)(pthread_cond_t *cond);
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static void (WINAPI *cond_signal)(pthread_cond_t *cond);
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static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex,
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static unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
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h->ret = h->func(h->arg);
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static int pthread_create(pthread_t *thread, const void *unused_attr,
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void *(*start_routine)(void*), void *arg)
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thread->func = start_routine;
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thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
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return !thread->handle;
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static void pthread_join(pthread_t thread, void **value_ptr)
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DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
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if (ret != WAIT_OBJECT_0)
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*value_ptr = thread.ret;
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CloseHandle(thread.handle);
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static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr)
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InitializeCriticalSection(m);
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static inline int pthread_mutex_destroy(pthread_mutex_t *m)
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DeleteCriticalSection(m);
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static inline int pthread_mutex_lock(pthread_mutex_t *m)
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EnterCriticalSection(m);
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static inline int pthread_mutex_unlock(pthread_mutex_t *m)
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LeaveCriticalSection(m);
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/* for pre-Windows 6.0 platforms we need to define and use our own condition
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* variable and api */
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typedef struct win32_cond_t {
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pthread_mutex_t mtx_broadcast;
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pthread_mutex_t mtx_waiter_count;
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volatile int waiter_count;
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volatile int is_broadcast;
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static void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
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win32_cond_t *win32_cond = NULL;
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/* non native condition variables */
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win32_cond = av_mallocz(sizeof(win32_cond_t));
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cond->ptr = win32_cond;
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win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
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if (!win32_cond->semaphore)
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win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
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if (!win32_cond->waiters_done)
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pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
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pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
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static void pthread_cond_destroy(pthread_cond_t *cond)
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win32_cond_t *win32_cond = cond->ptr;
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/* native condition variables do not destroy */
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/* non native condition variables */
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CloseHandle(win32_cond->semaphore);
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CloseHandle(win32_cond->waiters_done);
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pthread_mutex_destroy(&win32_cond->mtx_waiter_count);
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pthread_mutex_destroy(&win32_cond->mtx_broadcast);
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av_freep(&win32_cond);
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static void pthread_cond_broadcast(pthread_cond_t *cond)
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win32_cond_t *win32_cond = cond->ptr;
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if (cond_broadcast) {
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cond_broadcast(cond);
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/* non native condition variables */
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pthread_mutex_lock(&win32_cond->mtx_broadcast);
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pthread_mutex_lock(&win32_cond->mtx_waiter_count);
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if (win32_cond->waiter_count) {
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win32_cond->is_broadcast = 1;
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ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
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pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
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WaitForSingleObject(win32_cond->waiters_done, INFINITE);
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ResetEvent(win32_cond->waiters_done);
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win32_cond->is_broadcast = 0;
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pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
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pthread_mutex_unlock(&win32_cond->mtx_broadcast);
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static int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
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win32_cond_t *win32_cond = cond->ptr;
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cond_wait(cond, mutex, INFINITE);
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/* non native condition variables */
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pthread_mutex_lock(&win32_cond->mtx_broadcast);
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pthread_mutex_lock(&win32_cond->mtx_waiter_count);
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win32_cond->waiter_count++;
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pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
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pthread_mutex_unlock(&win32_cond->mtx_broadcast);
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// unlock the external mutex
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pthread_mutex_unlock(mutex);
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WaitForSingleObject(win32_cond->semaphore, INFINITE);
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pthread_mutex_lock(&win32_cond->mtx_waiter_count);
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win32_cond->waiter_count--;
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last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast;
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pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
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SetEvent(win32_cond->waiters_done);
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// lock the external mutex
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return pthread_mutex_lock(mutex);
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static void pthread_cond_signal(pthread_cond_t *cond)
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win32_cond_t *win32_cond = cond->ptr;
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pthread_mutex_lock(&win32_cond->mtx_broadcast);
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/* non-native condition variables */
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pthread_mutex_lock(&win32_cond->mtx_waiter_count);
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have_waiter = win32_cond->waiter_count;
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pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
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ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
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WaitForSingleObject(win32_cond->waiters_done, INFINITE);
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ResetEvent(win32_cond->waiters_done);
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pthread_mutex_unlock(&win32_cond->mtx_broadcast);
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static void w32thread_init(void)
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HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
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/* if one is available, then they should all be available */
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(void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
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(void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
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(void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
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(void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
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#endif /* AVCODEC_W32PTHREADS_H */
added
removed
libavcodec/w32pthreads.h
