queue.c
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/************************************************************************
*
* Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Modified for use in Linux by Mark Charlebois
*
************************************************************************/
// FIXME - need px4_queue
#include <queue.h>
#include <stddef.h>
void sq_rem(sq_entry_t *node, sq_queue_t *queue)
{
if (queue->head && node) {
if (node == queue->head) {
queue->head = node->flink;
if (node == queue->tail) {
queue->tail = NULL;
}
} else {
sq_entry_t *prev;
for (prev = (sq_entry_t *)queue->head;
prev && prev->flink != node;
prev = prev->flink) {}
if (prev) {
sq_remafter(prev, queue);
}
}
}
}
sq_entry_t *sq_remafter(sq_entry_t *node, sq_queue_t *queue)
{
sq_entry_t *ret = node->flink;
if (queue->head && ret) {
if (queue->tail == ret) {
queue->tail = node;
node->flink = NULL;
} else {
node->flink = ret->flink;
}
ret->flink = NULL;
}
return ret;
}
void sq_addfirst(sq_entry_t *node, sq_queue_t *queue)
{
node->flink = queue->head;
if (!queue->head) {
queue->tail = node;
}
queue->head = node;
}