yading@10: /*
yading@10:  * Copyright (C) 2010-2011 x264 project
yading@10:  *
yading@10:  * Authors: Steven Walters <kemuri9@gmail.com>
yading@10:  *          Pegasys Inc. <http://www.pegasys-inc.com>
yading@10:  *
yading@10:  * This file is part of Libav.
yading@10:  *
yading@10:  * Libav is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * Libav is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with Libav; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * w32threads to pthreads wrapper
yading@10:  */
yading@10: 
yading@10: #ifndef AVCODEC_W32PTHREADS_H
yading@10: #define AVCODEC_W32PTHREADS_H
yading@10: 
yading@10: /* Build up a pthread-like API using underlying Windows API. Have only static
yading@10:  * methods so as to not conflict with a potentially linked in pthread-win32
yading@10:  * library.
yading@10:  * As most functions here are used without checking return values,
yading@10:  * only implement return values as necessary. */
yading@10: 
yading@10: #define WIN32_LEAN_AND_MEAN
yading@10: #include <windows.h>
yading@10: #include <process.h>
yading@10: 
yading@10: #include "libavutil/common.h"
yading@10: #include "libavutil/internal.h"
yading@10: #include "libavutil/mem.h"
yading@10: 
yading@10: typedef struct pthread_t {
yading@10:     void *handle;
yading@10:     void *(*func)(void* arg);
yading@10:     void *arg;
yading@10:     void *ret;
yading@10: } pthread_t;
yading@10: 
yading@10: /* the conditional variable api for windows 6.0+ uses critical sections and
yading@10:  * not mutexes */
yading@10: typedef CRITICAL_SECTION pthread_mutex_t;
yading@10: 
yading@10: /* This is the CONDITIONAL_VARIABLE typedef for using Window's native
yading@10:  * conditional variables on kernels 6.0+.
yading@10:  * MinGW does not currently have this typedef. */
yading@10: typedef struct pthread_cond_t {
yading@10:     void *ptr;
yading@10: } pthread_cond_t;
yading@10: 
yading@10: /* function pointers to conditional variable API on windows 6.0+ kernels */
yading@10: static void (WINAPI *cond_broadcast)(pthread_cond_t *cond);
yading@10: static void (WINAPI *cond_init)(pthread_cond_t *cond);
yading@10: static void (WINAPI *cond_signal)(pthread_cond_t *cond);
yading@10: static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex,
yading@10:                                 DWORD milliseconds);
yading@10: 
yading@10: static unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
yading@10: {
yading@10:     pthread_t *h = arg;
yading@10:     h->ret = h->func(h->arg);
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int pthread_create(pthread_t *thread, const void *unused_attr,
yading@10:                           void *(*start_routine)(void*), void *arg)
yading@10: {
yading@10:     thread->func   = start_routine;
yading@10:     thread->arg    = arg;
yading@10:     thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
yading@10:                                            0, NULL);
yading@10:     return !thread->handle;
yading@10: }
yading@10: 
yading@10: static void pthread_join(pthread_t thread, void **value_ptr)
yading@10: {
yading@10:     DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
yading@10:     if (ret != WAIT_OBJECT_0)
yading@10:         return;
yading@10:     if (value_ptr)
yading@10:         *value_ptr = thread.ret;
yading@10:     CloseHandle(thread.handle);
yading@10: }
yading@10: 
yading@10: static inline int pthread_mutex_init(pthread_mutex_t *m, void* attr)
yading@10: {
yading@10:     InitializeCriticalSection(m);
yading@10:     return 0;
yading@10: }
yading@10: static inline int pthread_mutex_destroy(pthread_mutex_t *m)
yading@10: {
yading@10:     DeleteCriticalSection(m);
yading@10:     return 0;
yading@10: }
yading@10: static inline int pthread_mutex_lock(pthread_mutex_t *m)
yading@10: {
yading@10:     EnterCriticalSection(m);
yading@10:     return 0;
yading@10: }
yading@10: static inline int pthread_mutex_unlock(pthread_mutex_t *m)
yading@10: {
yading@10:     LeaveCriticalSection(m);
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: /* for pre-Windows 6.0 platforms we need to define and use our own condition
yading@10:  * variable and api */
yading@10: typedef struct  win32_cond_t {
yading@10:     pthread_mutex_t mtx_broadcast;
yading@10:     pthread_mutex_t mtx_waiter_count;
yading@10:     volatile int waiter_count;
yading@10:     HANDLE semaphore;
yading@10:     HANDLE waiters_done;
yading@10:     volatile int is_broadcast;
yading@10: } win32_cond_t;
yading@10: 
yading@10: static void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
yading@10: {
yading@10:     win32_cond_t *win32_cond = NULL;
yading@10:     if (cond_init) {
yading@10:         cond_init(cond);
yading@10:         return;
yading@10:     }
yading@10: 
yading@10:     /* non native condition variables */
yading@10:     win32_cond = av_mallocz(sizeof(win32_cond_t));
yading@10:     if (!win32_cond)
yading@10:         return;
yading@10:     cond->ptr = win32_cond;
yading@10:     win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
yading@10:     if (!win32_cond->semaphore)
yading@10:         return;
yading@10:     win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
yading@10:     if (!win32_cond->waiters_done)
yading@10:         return;
yading@10: 
yading@10:     pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
yading@10:     pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
yading@10: }
yading@10: 
yading@10: static void pthread_cond_destroy(pthread_cond_t *cond)
yading@10: {
yading@10:     win32_cond_t *win32_cond = cond->ptr;
yading@10:     /* native condition variables do not destroy */
yading@10:     if (cond_init)
yading@10:         return;
yading@10: 
yading@10:     /* non native condition variables */
yading@10:     CloseHandle(win32_cond->semaphore);
yading@10:     CloseHandle(win32_cond->waiters_done);
yading@10:     pthread_mutex_destroy(&win32_cond->mtx_waiter_count);
yading@10:     pthread_mutex_destroy(&win32_cond->mtx_broadcast);
yading@10:     av_freep(&win32_cond);
yading@10:     cond->ptr = NULL;
yading@10: }
yading@10: 
yading@10: static void pthread_cond_broadcast(pthread_cond_t *cond)
yading@10: {
yading@10:     win32_cond_t *win32_cond = cond->ptr;
yading@10:     int have_waiter;
yading@10: 
yading@10:     if (cond_broadcast) {
yading@10:         cond_broadcast(cond);
yading@10:         return;
yading@10:     }
yading@10: 
yading@10:     /* non native condition variables */
yading@10:     pthread_mutex_lock(&win32_cond->mtx_broadcast);
yading@10:     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
yading@10:     have_waiter = 0;
yading@10: 
yading@10:     if (win32_cond->waiter_count) {
yading@10:         win32_cond->is_broadcast = 1;
yading@10:         have_waiter = 1;
yading@10:     }
yading@10: 
yading@10:     if (have_waiter) {
yading@10:         ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
yading@10:         pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
yading@10:         WaitForSingleObject(win32_cond->waiters_done, INFINITE);
yading@10:         ResetEvent(win32_cond->waiters_done);
yading@10:         win32_cond->is_broadcast = 0;
yading@10:     } else
yading@10:         pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
yading@10:     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
yading@10: }
yading@10: 
yading@10: static int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
yading@10: {
yading@10:     win32_cond_t *win32_cond = cond->ptr;
yading@10:     int last_waiter;
yading@10:     if (cond_wait) {
yading@10:         cond_wait(cond, mutex, INFINITE);
yading@10:         return 0;
yading@10:     }
yading@10: 
yading@10:     /* non native condition variables */
yading@10:     pthread_mutex_lock(&win32_cond->mtx_broadcast);
yading@10:     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
yading@10:     win32_cond->waiter_count++;
yading@10:     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
yading@10:     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
yading@10: 
yading@10:     // unlock the external mutex
yading@10:     pthread_mutex_unlock(mutex);
yading@10:     WaitForSingleObject(win32_cond->semaphore, INFINITE);
yading@10: 
yading@10:     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
yading@10:     win32_cond->waiter_count--;
yading@10:     last_waiter = !win32_cond->waiter_count || !win32_cond->is_broadcast;
yading@10:     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
yading@10: 
yading@10:     if (last_waiter)
yading@10:         SetEvent(win32_cond->waiters_done);
yading@10: 
yading@10:     // lock the external mutex
yading@10:     return pthread_mutex_lock(mutex);
yading@10: }
yading@10: 
yading@10: static void pthread_cond_signal(pthread_cond_t *cond)
yading@10: {
yading@10:     win32_cond_t *win32_cond = cond->ptr;
yading@10:     int have_waiter;
yading@10:     if (cond_signal) {
yading@10:         cond_signal(cond);
yading@10:         return;
yading@10:     }
yading@10: 
yading@10:     pthread_mutex_lock(&win32_cond->mtx_broadcast);
yading@10: 
yading@10:     /* non-native condition variables */
yading@10:     pthread_mutex_lock(&win32_cond->mtx_waiter_count);
yading@10:     have_waiter = win32_cond->waiter_count;
yading@10:     pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
yading@10: 
yading@10:     if (have_waiter) {
yading@10:         ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
yading@10:         WaitForSingleObject(win32_cond->waiters_done, INFINITE);
yading@10:         ResetEvent(win32_cond->waiters_done);
yading@10:     }
yading@10: 
yading@10:     pthread_mutex_unlock(&win32_cond->mtx_broadcast);
yading@10: }
yading@10: 
yading@10: static void w32thread_init(void)
yading@10: {
yading@10:     HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
yading@10:     /* if one is available, then they should all be available */
yading@10:     cond_init      =
yading@10:         (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
yading@10:     cond_broadcast =
yading@10:         (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
yading@10:     cond_signal    =
yading@10:         (void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
yading@10:     cond_wait      =
yading@10:         (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
yading@10: }
yading@10: 
yading@10: #endif /* AVCODEC_W32PTHREADS_H */