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/*
ChibiOS/RT - Copyright (C) 2006-2007 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file chlists.c
* @brief Thread queues/lists code.
* @note All the functions present in this module, while public, are not
* an OS API and should not be directly used in the user applications
* code.
*
* @addtogroup internals
* @{
*/
#include "ch.h"
#if !CH_OPTIMIZE_SPEED || defined(__DOXYGEN__)
/**
* @brief Inserts a thread into a priority ordered queue.
* @note The insertion is done by scanning the list from the highest priority
* toward the lowest.
* @note This function is @b not an API.
*
* @param[in] tp the pointer to the thread to be inserted in the list
* @param[in] tqp the pointer to the threads list header
*/
void prio_insert(Thread *tp, ThreadsQueue *tqp) {
/* cp iterates over the queue.*/
Thread *cp = (Thread *)tqp;
do {
/* Iterate to next thread in queue.*/
cp = cp->p_next;
/* Not end of queue? and cp has equal or higher priority than tp?.*/
} while ((cp != (Thread *)tqp) && (cp->p_prio >= tp->p_prio));
/* Insert before cp, point tp to next and prev in queue.*/
tp->p_prev = (tp->p_next = cp)->p_prev;
/* Make prev point to tp, and cp point back to tp.*/
tp->p_prev->p_next = cp->p_prev = tp;
}
/**
* @brief Inserts a Thread into a queue.
* @note This function is @b not an API.
*
* @param[in] tp the pointer to the thread to be inserted in the list
* @param[in] tqp the pointer to the threads list header
*/
void queue_insert(Thread *tp, ThreadsQueue *tqp) {
tp->p_prev = (tp->p_next = (Thread *)tqp)->p_prev;
tp->p_prev->p_next = tqp->p_prev = tp;
}
/**
* @brief Removes the first-out Thread from a queue and returns it.
* @note If the queue is priority ordered then this function returns the
* thread with the highest priority.
* @note This function is @b not an API.
*
* @param[in] tqp the pointer to the threads list header
* @return The removed thread pointer.
*/
Thread *fifo_remove(ThreadsQueue *tqp) {
Thread *tp = tqp->p_next;
(tqp->p_next = tp->p_next)->p_prev = (Thread *)tqp;
return tp;
}
/**
* @brief Removes the last-out Thread from a queue and returns it.
* @note If the queue is priority ordered then this function returns the
* thread with the lowest priority.
* @note This function is @b not an API.
*
* @param[in] tqp the pointer to the threads list header
* @return The removed thread pointer.
*/
Thread *lifo_remove(ThreadsQueue *tqp) {
Thread *tp = tqp->p_prev;
(tqp->p_prev = tp->p_prev)->p_next = (Thread *)tqp;
return tp;
}
/**
* @brief Removes a Thread from a queue and returns it.
* @details The thread is removed from the queue regardless of its relative
* position and regardless the used insertion method.
* @note This function is @b not an API.
*
* @param[in] tp the pointer to the thread to be removed from the queue
* @return The removed thread pointer.
*/
Thread *dequeue(Thread *tp) {
tp->p_prev->p_next = tp->p_next;
tp->p_next->p_prev = tp->p_prev;
return tp;
}
/**
* @brief Pushes a Thread on top of a stack list.
* @note This function is @b not an API.
*
* @param[in] tp the pointer to the thread to be inserted in the list
* @param[in] tlp the pointer to the threads list header
*/
void list_insert(Thread *tp, ThreadsList *tlp) {
tp->p_next = tlp->p_next;
tlp->p_next = tp;
}
/**
* @brief Pops a Thread from the top of a stack list and returns it.
* @note The list must be non-empty before calling this function.
* @note This function is @b not an API.
*
* @param[in] tlp the pointer to the threads list header
* @return The removed thread pointer.
*/
Thread *list_remove(ThreadsList *tlp) {
Thread *tp = tlp->p_next;
tlp->p_next = tp->p_next;
return tp;
}
#endif /* CH_OPTIMIZE_SPEED */
/** @} */
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