/*
* 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 void 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;
}
/* 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 */