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//this is a single reader [maybe multiple writer?] byte queue
//Copyright 2008 Alex Norman
//writen by Alex Norman
//
//This file is part of avr-bytequeue.
//
//avr-bytequeue 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.
//
//avr-bytequeue 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 avr-bytequeue. If not, see <http://www.gnu.org/licenses/>.
#include "bytequeue.h"
#include "interrupt_setting.h"
void bytequeue_init(byteQueue_t * queue, uint8_t * dataArray, byteQueueIndex_t arrayLen){
queue->length = arrayLen;
queue->data = dataArray;
queue->start = queue->end = 0;
}
bool bytequeue_enqueue(byteQueue_t * queue, uint8_t item){
interrupt_setting_t setting = store_and_clear_interrupt();
//full
if(((queue->end + 1) % queue->length) == queue->start){
restore_interrupt_setting(setting);
return false;
} else {
queue->data[queue->end] = item;
queue->end = (queue->end + 1) % queue->length;
restore_interrupt_setting(setting);
return true;
}
}
byteQueueIndex_t bytequeue_length(byteQueue_t * queue){
byteQueueIndex_t len;
interrupt_setting_t setting = store_and_clear_interrupt();
if(queue->end >= queue->start)
len = queue->end - queue->start;
else
len = (queue->length - queue->start) + queue->end;
restore_interrupt_setting(setting);
return len;
}
//we don't need to avoid interrupts if there is only one reader
uint8_t bytequeue_get(byteQueue_t * queue, byteQueueIndex_t index){
return queue->data[(queue->start + index) % queue->length];
}
//we just update the start index to remove elements
void bytequeue_remove(byteQueue_t * queue, byteQueueIndex_t numToRemove){
interrupt_setting_t setting = store_and_clear_interrupt();
queue->start = (queue->start + numToRemove) % queue->length;
restore_interrupt_setting(setting);
}
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