/* SPDX-License-Identifier: BSD-2-Clause */
/* Shm_Envelope_control *Shm_Locked_queue_Get( lq_cb )
*
* This routine returns an envelope control block from a shared
* memory queue.
*
* Input parameters:
* lq_cb - pointer to a locked queue control block
*
* Output parameters:
* returns - pointer to an envelope control block
* - NULL if no envelopes on specified queue
*
* COPYRIGHT (c) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* 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.
*
* 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.
*/
#include <rtems.h>
#include <shm_driver.h>
Shm_Envelope_control *Shm_Locked_queue_Get(
Shm_Locked_queue_Control *lq_cb
)
{
Shm_Envelope_control *tmp_ecb;
uint32_t tmpfront;
tmp_ecb = NULL;
Shm_Lock( lq_cb );
tmpfront = Shm_Convert(lq_cb->front);
if ( tmpfront != Shm_Locked_queue_End_of_list ) {
tmp_ecb = &Shm_Envelopes[ tmpfront ];
lq_cb->front = tmp_ecb->next;
if ( tmp_ecb->next == Shm_Locked_queue_End_of_list )
lq_cb->rear = Shm_Locked_queue_End_of_list;
tmp_ecb->next = Shm_Locked_queue_Not_on_list;
}
Shm_Unlock( lq_cb );
return( tmp_ecb );
}