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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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