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/*
* Copyright (c) 2005 Washington University in St. Louis.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - Neither the name of the copyright holders 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 HOLDER 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.
*/
/**
*
* @author Kevin Klues (klueska@cs.wustl.edu)
* @version $Revision: 1.7 $
* @date $Date: 2010-06-29 22:07:56 $
*/
#include "Resource.h"
generic module RoundRobinResourceQueueC(uint8_t size) @safe() {
provides {
interface Init;
interface ResourceQueue as RoundRobinQueue;
}
}
implementation {
enum {
NO_ENTRY = 0xFF,
SIZE = size ? (size - 1) / 8 + 1 : 0
};
uint8_t resQ[SIZE];
uint8_t last = 0;
void clearEntry(uint8_t id) {
resQ[id / 8] &= ~(1 << (id % 8));
}
command error_t Init.init() {
memset(resQ, 0, sizeof(resQ));
return SUCCESS;
}
async command bool RoundRobinQueue.isEmpty() {
int i;
atomic {
for (i = 0; i<sizeof(resQ); i++)
if(resQ[i] > 0) return FALSE;
return TRUE;
}
}
async command bool RoundRobinQueue.isEnqueued(resource_client_id_t id) {
return resQ[id / 8] & (1 << (id % 8));
}
async command resource_client_id_t RoundRobinQueue.dequeue() {
int i;
atomic {
for (i = last+1; ; i++) {
if(i == size)
i = 0;
if (call RoundRobinQueue.isEnqueued(i)) {
clearEntry(i);
last = i;
return i;
}
if (i == last)
break;
}
return NO_ENTRY;
}
}
async command error_t RoundRobinQueue.enqueue(resource_client_id_t id) {
atomic {
if (!(call RoundRobinQueue.isEnqueued(id))) {
resQ[id / 8] |= 1 << (id % 8);
return SUCCESS;
}
return EBUSY;
}
}
}
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