Subversion Repositories Kolibri OS

/*

 * Copyright (C) 2010-2011 x264 project

 *

 * Authors: Steven Walters 

 *          Pegasys Inc. 

 *

 * 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 

#include 

#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 CONDITIONAL_VARIABLE typedef for using Window's native

 * conditional variables on kernels 6.0+.

 * MinGW does not currently have this typedef. */

typedef struct pthread_cond_t {

    void *ptr;

} pthread_cond_t;

/* function pointers to conditional variable API on windows 6.0+ kernels */

#if _WIN32_WINNT < 0x0600

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);

#else

#define cond_init      InitializeConditionVariable

#define cond_broadcast WakeAllConditionVariable

#define cond_signal    WakeConditionVariable

#define cond_wait      SleepConditionVariableCS

#endif

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  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;

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)

{

#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 */