From 90f9a5830b5d332de7ebb1ab45589f1870cbd65d Mon Sep 17 00:00:00 2001 From: Anton Khirnov Date: Sun, 12 May 2013 08:11:42 +0200 Subject: w32pthreads: move from lavc to compat/ It will be used in other places than lavc. --- compat/w32pthreads.h | 279 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 279 insertions(+) create mode 100644 compat/w32pthreads.h (limited to 'compat') diff --git a/compat/w32pthreads.h b/compat/w32pthreads.h new file mode 100644 index 0000000..a5ff6ac --- /dev/null +++ b/compat/w32pthreads.h @@ -0,0 +1,279 @@ +/* + * Copyright (C) 2010-2011 x264 project + * + * Authors: Steven Walters + * Pegasys Inc. + * + * 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 LIBAV_W32PTHREADS_H +#define LIBAV_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/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 */ +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 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"); +#else + cond_init = InitializeConditionVariable; + cond_broadcast = WakeAllConditionVariable; + cond_signal = WakeConditionVariable; + cond_wait = SleepConditionVariableCS; +#endif + +} + +#endif /* LIBAV_W32PTHREADS_H */ -- cgit v1.1