compat/w32pthreads.h - third_party/ffmpeg - Git at Google

 /*
  * Copyright (C) 2010-2011 x264 project
  *
  * Authors: Steven Walters <kemuri9@gmail.com>
  *          Pegasys Inc. <http://www.pegasys-inc.com>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg 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.
  *
  * FFmpeg 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 FFmpeg; 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 FFMPEG_COMPAT_W32PTHREADS_H
 #define FFMPEG_COMPAT_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>

 #include "libavutil/attributes.h"
 #include "libavutil/common.h"
 #include "libavutil/internal.h"
 #include "libavutil/mem.h"

 typedef struct pthread_t {
     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 CONDITION_VARIABLE typedef for using Windows' native
  * conditional variables on kernels 6.0+. */
 #if HAVE_CONDITION_VARIABLE_PTR
 typedef CONDITION_VARIABLE pthread_cond_t;
 #else
 typedef struct pthread_cond_t {
     void *Ptr;
 } pthread_cond_t;
 #endif

 #if _WIN32_WINNT >= 0x0600
 #define InitializeCriticalSection(x) InitializeCriticalSectionEx(x, 0, 0)
 #define WaitForSingleObject(a, b) WaitForSingleObjectEx(a, b, FALSE)
 #endif

 static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
 {
     pthread_t *h = arg;
     h->ret = h->func(h->arg);
     return 0;
 }

 static av_unused 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 av_unused 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;
 }

 #if _WIN32_WINNT >= 0x0600
 static inline int pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
 {
     InitializeConditionVariable(cond);
     return 0;
 }

 /* native condition variables do not destroy */
 static inline void pthread_cond_destroy(pthread_cond_t *cond)
 {
     return;
 }

 static inline void pthread_cond_broadcast(pthread_cond_t *cond)
 {
     WakeAllConditionVariable(cond);
 }

 static inline int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
 {
     SleepConditionVariableCS(cond, mutex, INFINITE);
     return 0;
 }

 static inline void pthread_cond_signal(pthread_cond_t *cond)
 {
     WakeConditionVariable(cond);
 }

 #else // _WIN32_WINNT < 0x0600
 /* for pre-Windows 6.0 platforms we need to define and use our own condition
  * variable and api */
 typedef struct  win32_cond_t {
     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;

 /* 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 av_unused int pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
 {
     win32_cond_t *win32_cond = NULL;
     if (cond_init) {
         cond_init(cond);
         return 0;
     }

     /* non native condition variables */
     win32_cond = av_mallocz(sizeof(win32_cond_t));
     if (!win32_cond)
         return ENOMEM;
     cond->Ptr = win32_cond;
     win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
     if (!win32_cond->semaphore)
         return ENOMEM;
     win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
     if (!win32_cond->waiters_done)
         return ENOMEM;

     pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
     pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
     return 0;
 }

 static av_unused 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 av_unused 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 av_unused 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 av_unused 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);
 }
 #endif

 static av_unused void w32thread_init(void)
 {
 #if _WIN32_WINNT < 0x0600
     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

 }

 #endif /* FFMPEG_COMPAT_W32PTHREADS_H */
	/*
	* Copyright (C) 2010-2011 x264 project
	*
	* Authors: Steven Walters <kemuri9@gmail.com>
	* Pegasys Inc. <http://www.pegasys-inc.com>
	*
	* This file is part of FFmpeg.
	*
	* FFmpeg 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.
	*
	* FFmpeg 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 FFmpeg; 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 FFMPEG_COMPAT_W32PTHREADS_H
	#define FFMPEG_COMPAT_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>

	#include "libavutil/attributes.h"
	#include "libavutil/common.h"
	#include "libavutil/internal.h"
	#include "libavutil/mem.h"

	typedef struct pthread_t {
	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 CONDITION_VARIABLE typedef for using Windows' native
	* conditional variables on kernels 6.0+. */
	#if HAVE_CONDITION_VARIABLE_PTR
	typedef CONDITION_VARIABLE pthread_cond_t;
	#else
	typedef struct pthread_cond_t {
	void *Ptr;
	} pthread_cond_t;
	#endif

	#if _WIN32_WINNT >= 0x0600
	#define InitializeCriticalSection(x) InitializeCriticalSectionEx(x, 0, 0)
	#define WaitForSingleObject(a, b) WaitForSingleObjectEx(a, b, FALSE)
	#endif

	static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
	{
	pthread_t *h = arg;
	h->ret = h->func(h->arg);
	return 0;
	}

	static av_unused 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 av_unused 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;
	}

	#if _WIN32_WINNT >= 0x0600
	static inline int pthread_cond_init(pthread_cond_t cond, const void unused_attr)
	{
	InitializeConditionVariable(cond);
	return 0;
	}

	/* native condition variables do not destroy */
	static inline void pthread_cond_destroy(pthread_cond_t *cond)
	{
	return;
	}

	static inline void pthread_cond_broadcast(pthread_cond_t *cond)
	{
	WakeAllConditionVariable(cond);
	}

	static inline int pthread_cond_wait(pthread_cond_t cond, pthread_mutex_t mutex)
	{
	SleepConditionVariableCS(cond, mutex, INFINITE);
	return 0;
	}

	static inline void pthread_cond_signal(pthread_cond_t *cond)
	{
	WakeConditionVariable(cond);
	}

	#else // _WIN32_WINNT < 0x0600
	/* for pre-Windows 6.0 platforms we need to define and use our own condition
	* variable and api */
	typedef struct win32_cond_t {
	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;

	/* 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 av_unused int pthread_cond_init(pthread_cond_t cond, const void unused_attr)
	{
	win32_cond_t *win32_cond = NULL;
	if (cond_init) {
	cond_init(cond);
	return 0;
	}

	/* non native condition variables */
	win32_cond = av_mallocz(sizeof(win32_cond_t));
	if (!win32_cond)
	return ENOMEM;
	cond->Ptr = win32_cond;
	win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
	if (!win32_cond->semaphore)
	return ENOMEM;
	win32_cond->waiters_done = CreateEvent(NULL, TRUE, FALSE, NULL);
	if (!win32_cond->waiters_done)
	return ENOMEM;

	pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
	pthread_mutex_init(&win32_cond->mtx_broadcast, NULL);
	return 0;
	}

	static av_unused 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 av_unused 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 av_unused 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 av_unused 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);
	}
	#endif

	static av_unused void w32thread_init(void)
	{
	#if _WIN32_WINNT < 0x0600
	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

	}

	#endif /* FFMPEG_COMPAT_W32PTHREADS_H */