Added a wrapper class around POSIX semaphores.
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@ -62,6 +62,7 @@ selectors/traffic_selector.c selectors/traffic_selector.h \
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threading/thread.h threading/thread.c \
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threading/thread_value.h threading/thread_value.c \
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threading/mutex.h threading/mutex.c threading/condvar.h \
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threading/semaphore.h threading/semaphore.c \
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threading/rwlock.h threading/rwlock.c \
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threading/lock_profiler.h \
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utils.h utils.c \
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@ -60,6 +60,7 @@ selectors/traffic_selector.c selectors/traffic_selector.h \
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threading/thread.h threading/thread.c \
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threading/thread_value.h threading/thread_value.c \
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threading/mutex.h threading/mutex.c threading/condvar.h \
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threading/semaphore.h threading/semaphore.c \
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threading/rwlock.h threading/rwlock.c \
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threading/lock_profiler.h \
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utils.h utils.c \
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@ -0,0 +1,106 @@
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/*
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* Copyright (C) 2011 Tobias Brunner
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* Hochschule fuer Technik Rapperswil
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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#include <semaphore.h>
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#include <library.h>
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#include "semaphore.h"
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typedef struct private_semaphore_t private_semaphore_t;
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/**
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* private data of a semaphore
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*/
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struct private_semaphore_t {
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/**
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* public interface
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*/
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semaphore_t public;
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/**
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* wrapped POSIX semaphore object
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*/
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sem_t sem;
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};
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METHOD(semaphore_t, wait_, void,
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private_semaphore_t *this)
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{
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sem_wait(&this->sem);
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}
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METHOD(semaphore_t, timed_wait_abs, bool,
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private_semaphore_t *this, timeval_t tv)
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{
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timespec_t ts;
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ts.tv_sec = tv.tv_sec;
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ts.tv_nsec = tv.tv_usec * 1000;
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/* there are errors other than ETIMEDOUT possible, but we consider them
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* all as timeout */
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return sem_timedwait(&this->sem, &ts) == -1;
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}
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METHOD(semaphore_t, timed_wait, bool,
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private_semaphore_t *this, u_int timeout)
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{
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timeval_t tv, add;
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add.tv_sec = timeout / 1000;
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add.tv_usec = (timeout % 1000) * 1000;
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time_monotonic(&tv);
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timeradd(&tv, &add, &tv);
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return timed_wait_abs(this, tv);
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}
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METHOD(semaphore_t, post, void,
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private_semaphore_t *this)
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{
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sem_post(&this->sem);
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}
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METHOD(semaphore_t, destroy, void,
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private_semaphore_t *this)
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{
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sem_destroy(&this->sem);
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free(this);
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}
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/*
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* Described in header
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*/
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semaphore_t *semaphore_create(u_int value)
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{
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private_semaphore_t *this;
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INIT(this,
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.public = {
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.wait = _wait_,
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.timed_wait = _timed_wait,
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.timed_wait_abs = _timed_wait_abs,
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.post = _post,
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.destroy = _destroy,
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},
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);
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sem_init(&this->sem, 0, value);
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return &this->public;
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}
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@ -0,0 +1,85 @@
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/*
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* Copyright (C) 2011 Tobias Brunner
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* Hochschule fuer Technik Rapperswil
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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/**
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* @defgroup semaphore semaphore
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* @{ @ingroup threading
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*/
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#ifndef THREADING_SEMAPHORE_H_
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#define THREADING_SEMAPHORE_H_
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typedef struct semaphore_t semaphore_t;
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/**
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* A semaphore is basically an integer whose value is never allowed to be
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* lower than 0. Two operations can be performed on it: increment the
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* value by one, and decrement the value by one. If the value is currently
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* zero, then the decrement operation will blcok until the value becomes
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* greater than zero.
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*/
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struct semaphore_t {
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/**
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* Decrease the value by one, if it is greater than zero. Otherwise the
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* current thread is blocked and it waits until the value increases.
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*/
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void (*wait)(semaphore_t *this);
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/**
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* Decrease the value by one, if it is greater than zero. Otherwise the
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* current thread is blocked and it waits until the value increases, or the
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* call times out.
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*
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* @param timeout timeout im ms
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* @return TRUE if timed out, FALSE otherwise
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*/
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bool (*timed_wait)(semaphore_t *this, u_int timeout);
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/**
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* Decrease the value by one, if it is greater than zero. Otherwise the
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* current thread is blocked and it waits until the value increases, or the
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* call times out.
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*
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* The passed timeval should be calculated based on the time_monotonic()
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* function.
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*
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* @param tv absolute time until timeout
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* @return TRUE if timed out, FALSE otherwise
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*/
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bool (*timed_wait_abs)(semaphore_t *this, timeval_t tv);
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/**
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* Increase the value by one. If the value becomes greater than zero, then
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* another thread waiting will be woken up.
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*/
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void (*post)(semaphore_t *this);
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/**
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* Destroy a semaphore and free its resources.
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*/
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void (*destroy)(semaphore_t *this);
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};
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/**
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* Create a semaphore instance.
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*
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* @param value initial value (typically 0)
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* @return semaphore instance
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*/
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semaphore_t *semaphore_create(u_int value);
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#endif /** THREADING_SEMAPHORE_H_ @} */
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