diff options
Diffstat (limited to 'drivers/webpold/utils/thread.c')
-rw-r--r-- | drivers/webpold/utils/thread.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/drivers/webpold/utils/thread.c b/drivers/webpold/utils/thread.c new file mode 100644 index 0000000000..ce89cf9dc7 --- /dev/null +++ b/drivers/webpold/utils/thread.c @@ -0,0 +1,247 @@ +// Copyright 2011 Google Inc. All Rights Reserved. +// +// This code is licensed under the same terms as WebM: +// Software License Agreement: http://www.webmproject.org/license/software/ +// Additional IP Rights Grant: http://www.webmproject.org/license/additional/ +// ----------------------------------------------------------------------------- +// +// Multi-threaded worker +// +// Author: Skal (pascal.massimino@gmail.com) + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include <assert.h> +#include <string.h> // for memset() +#include "./thread.h" + +#if defined(__cplusplus) || defined(c_plusplus) +extern "C" { +#endif + +#ifdef WEBP_USE_THREAD + +#if defined(_WIN32) + +//------------------------------------------------------------------------------ +// simplistic pthread emulation layer + +#include <process.h> + +// _beginthreadex requires __stdcall +#define THREADFN unsigned int __stdcall +#define THREAD_RETURN(val) (unsigned int)((DWORD_PTR)val) + +static int pthread_create(pthread_t* const thread, const void* attr, + unsigned int (__stdcall *start)(void*), void* arg) { + (void)attr; + *thread = (pthread_t)_beginthreadex(NULL, /* void *security */ + 0, /* unsigned stack_size */ + start, + arg, + 0, /* unsigned initflag */ + NULL); /* unsigned *thrdaddr */ + if (*thread == NULL) return 1; + SetThreadPriority(*thread, THREAD_PRIORITY_ABOVE_NORMAL); + return 0; +} + +static int pthread_join(pthread_t thread, void** value_ptr) { + (void)value_ptr; + return (WaitForSingleObject(thread, INFINITE) != WAIT_OBJECT_0 || + CloseHandle(thread) == 0); +} + +// Mutex +static int pthread_mutex_init(pthread_mutex_t* const mutex, void* mutexattr) { + (void)mutexattr; + InitializeCriticalSection(mutex); + return 0; +} + +static int pthread_mutex_lock(pthread_mutex_t* const mutex) { + EnterCriticalSection(mutex); + return 0; +} + +static int pthread_mutex_unlock(pthread_mutex_t* const mutex) { + LeaveCriticalSection(mutex); + return 0; +} + +static int pthread_mutex_destroy(pthread_mutex_t* const mutex) { + DeleteCriticalSection(mutex); + return 0; +} + +// Condition +static int pthread_cond_destroy(pthread_cond_t* const condition) { + int ok = 1; + ok &= (CloseHandle(condition->waiting_sem_) != 0); + ok &= (CloseHandle(condition->received_sem_) != 0); + ok &= (CloseHandle(condition->signal_event_) != 0); + return !ok; +} + +static int pthread_cond_init(pthread_cond_t* const condition, void* cond_attr) { + (void)cond_attr; + condition->waiting_sem_ = CreateSemaphore(NULL, 0, 1, NULL); + condition->received_sem_ = CreateSemaphore(NULL, 0, 1, NULL); + condition->signal_event_ = CreateEvent(NULL, FALSE, FALSE, NULL); + if (condition->waiting_sem_ == NULL || + condition->received_sem_ == NULL || + condition->signal_event_ == NULL) { + pthread_cond_destroy(condition); + return 1; + } + return 0; +} + +static int pthread_cond_signal(pthread_cond_t* const condition) { + int ok = 1; + if (WaitForSingleObject(condition->waiting_sem_, 0) == WAIT_OBJECT_0) { + // a thread is waiting in pthread_cond_wait: allow it to be notified + ok = SetEvent(condition->signal_event_); + // wait until the event is consumed so the signaler cannot consume + // the event via its own pthread_cond_wait. + ok &= (WaitForSingleObject(condition->received_sem_, INFINITE) != + WAIT_OBJECT_0); + } + return !ok; +} + +static int pthread_cond_wait(pthread_cond_t* const condition, + pthread_mutex_t* const mutex) { + int ok; + // note that there is a consumer available so the signal isn't dropped in + // pthread_cond_signal + if (!ReleaseSemaphore(condition->waiting_sem_, 1, NULL)) + return 1; + // now unlock the mutex so pthread_cond_signal may be issued + pthread_mutex_unlock(mutex); + ok = (WaitForSingleObject(condition->signal_event_, INFINITE) == + WAIT_OBJECT_0); + ok &= ReleaseSemaphore(condition->received_sem_, 1, NULL); + pthread_mutex_lock(mutex); + return !ok; +} + +#else // _WIN32 +# define THREADFN void* +# define THREAD_RETURN(val) val +#endif + +//------------------------------------------------------------------------------ + +static THREADFN WebPWorkerThreadLoop(void *ptr) { // thread loop + WebPWorker* const worker = (WebPWorker*)ptr; + int done = 0; + while (!done) { + pthread_mutex_lock(&worker->mutex_); + while (worker->status_ == OK) { // wait in idling mode + pthread_cond_wait(&worker->condition_, &worker->mutex_); + } + if (worker->status_ == WORK) { + if (worker->hook) { + worker->had_error |= !worker->hook(worker->data1, worker->data2); + } + worker->status_ = OK; + } else if (worker->status_ == NOT_OK) { // finish the worker + done = 1; + } + // signal to the main thread that we're done (for Sync()) + pthread_cond_signal(&worker->condition_); + pthread_mutex_unlock(&worker->mutex_); + } + return THREAD_RETURN(NULL); // Thread is finished +} + +// main thread state control +static void WebPWorkerChangeState(WebPWorker* const worker, + WebPWorkerStatus new_status) { + // no-op when attempting to change state on a thread that didn't come up + if (worker->status_ < OK) return; + + pthread_mutex_lock(&worker->mutex_); + // wait for the worker to finish + while (worker->status_ != OK) { + pthread_cond_wait(&worker->condition_, &worker->mutex_); + } + // assign new status and release the working thread if needed + if (new_status != OK) { + worker->status_ = new_status; + pthread_cond_signal(&worker->condition_); + } + pthread_mutex_unlock(&worker->mutex_); +} + +#endif + +//------------------------------------------------------------------------------ + +void WebPWorkerInit(WebPWorker* const worker) { + memset(worker, 0, sizeof(*worker)); + worker->status_ = NOT_OK; +} + +int WebPWorkerSync(WebPWorker* const worker) { +#ifdef WEBP_USE_THREAD + WebPWorkerChangeState(worker, OK); +#endif + assert(worker->status_ <= OK); + return !worker->had_error; +} + +int WebPWorkerReset(WebPWorker* const worker) { + int ok = 1; + worker->had_error = 0; + if (worker->status_ < OK) { +#ifdef WEBP_USE_THREAD + if (pthread_mutex_init(&worker->mutex_, NULL) || + pthread_cond_init(&worker->condition_, NULL)) { + return 0; + } + pthread_mutex_lock(&worker->mutex_); + ok = !pthread_create(&worker->thread_, NULL, WebPWorkerThreadLoop, worker); + if (ok) worker->status_ = OK; + pthread_mutex_unlock(&worker->mutex_); +#else + worker->status_ = OK; +#endif + } else if (worker->status_ > OK) { + ok = WebPWorkerSync(worker); + } + assert(!ok || (worker->status_ == OK)); + return ok; +} + +void WebPWorkerLaunch(WebPWorker* const worker) { +#ifdef WEBP_USE_THREAD + WebPWorkerChangeState(worker, WORK); +#else + if (worker->hook) + worker->had_error |= !worker->hook(worker->data1, worker->data2); +#endif +} + +void WebPWorkerEnd(WebPWorker* const worker) { + if (worker->status_ >= OK) { +#ifdef WEBP_USE_THREAD + WebPWorkerChangeState(worker, NOT_OK); + pthread_join(worker->thread_, NULL); + pthread_mutex_destroy(&worker->mutex_); + pthread_cond_destroy(&worker->condition_); +#else + worker->status_ = NOT_OK; +#endif + } + assert(worker->status_ == NOT_OK); +} + +//------------------------------------------------------------------------------ + +#if defined(__cplusplus) || defined(c_plusplus) +} // extern "C" +#endif |