1 //this is a single reader [maybe multiple writer?] byte queue
2 //Copyright 2008 Alex Norman
3 //writen by Alex Norman
5 //This file is part of avr-bytequeue.
7 //avr-bytequeue is free software: you can redistribute it and/or modify
8 //it under the terms of the GNU General Public License as published by
9 //the Free Software Foundation, either version 3 of the License, or
10 //(at your option) any later version.
12 //avr-bytequeue is distributed in the hope that it will be useful,
13 //but WITHOUT ANY WARRANTY; without even the implied warranty of
14 //MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 //GNU General Public License for more details.
17 //You should have received a copy of the GNU General Public License
18 //along with avr-bytequeue. If not, see <http://www.gnu.org/licenses/>.
20 #include "bytequeue.h"
21 #include "interrupt_setting.h"
23 void bytequeue_init(byteQueue_t * queue, uint8_t * dataArray, byteQueueIndex_t arrayLen){
24 queue->length = arrayLen;
25 queue->data = dataArray;
26 queue->start = queue->end = 0;
29 bool bytequeue_enqueue(byteQueue_t * queue, uint8_t item){
30 interrupt_setting_t setting = store_and_clear_interrupt();
32 if(((queue->end + 1) % queue->length) == queue->start){
33 restore_interrupt_setting(setting);
36 queue->data[queue->end] = item;
37 queue->end = (queue->end + 1) % queue->length;
38 restore_interrupt_setting(setting);
43 byteQueueIndex_t bytequeue_length(byteQueue_t * queue){
45 interrupt_setting_t setting = store_and_clear_interrupt();
46 if(queue->end >= queue->start)
47 len = queue->end - queue->start;
49 len = (queue->length - queue->start) + queue->end;
50 restore_interrupt_setting(setting);
54 //we don't need to avoid interrupts if there is only one reader
55 uint8_t bytequeue_get(byteQueue_t * queue, byteQueueIndex_t index){
56 return queue->data[(queue->start + index) % queue->length];
59 //we just update the start index to remove elements
60 void bytequeue_remove(byteQueue_t * queue, byteQueueIndex_t numToRemove){
61 interrupt_setting_t setting = store_and_clear_interrupt();
62 queue->start = (queue->start + numToRemove) % queue->length;
63 restore_interrupt_setting(setting);