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66 lines
2.2 KiB
66 lines
2.2 KiB
10 years ago
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//this is a single reader [maybe multiple writer?] byte queue
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//Copyright 2008 Alex Norman
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//writen by Alex Norman
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//
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//This file is part of avr-bytequeue.
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//
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//avr-bytequeue is free software: you can redistribute it and/or modify
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//it under the terms of the GNU General Public License as published by
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//the Free Software Foundation, either version 3 of the License, or
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//(at your option) any later version.
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//
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//avr-bytequeue is distributed in the hope that it will be useful,
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//but WITHOUT ANY WARRANTY; without even the implied warranty of
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//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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//GNU General Public License for more details.
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//
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//You should have received a copy of the GNU General Public License
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//along with avr-bytequeue. If not, see <http://www.gnu.org/licenses/>.
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#include "bytequeue.h"
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#include "interrupt_setting.h"
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void bytequeue_init(byteQueue_t * queue, uint8_t * dataArray, byteQueueIndex_t arrayLen){
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queue->length = arrayLen;
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queue->data = dataArray;
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queue->start = queue->end = 0;
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}
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bool bytequeue_enqueue(byteQueue_t * queue, uint8_t item){
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interrupt_setting_t setting = store_and_clear_interrupt();
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//full
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if(((queue->end + 1) % queue->length) == queue->start){
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restore_interrupt_setting(setting);
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return false;
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} else {
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queue->data[queue->end] = item;
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queue->end = (queue->end + 1) % queue->length;
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restore_interrupt_setting(setting);
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return true;
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}
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}
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byteQueueIndex_t bytequeue_length(byteQueue_t * queue){
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byteQueueIndex_t len;
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interrupt_setting_t setting = store_and_clear_interrupt();
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if(queue->end >= queue->start)
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len = queue->end - queue->start;
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else
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len = (queue->length - queue->start) + queue->end;
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restore_interrupt_setting(setting);
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return len;
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}
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//we don't need to avoid interrupts if there is only one reader
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uint8_t bytequeue_get(byteQueue_t * queue, byteQueueIndex_t index){
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return queue->data[(queue->start + index) % queue->length];
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}
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//we just update the start index to remove elements
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void bytequeue_remove(byteQueue_t * queue, byteQueueIndex_t numToRemove){
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interrupt_setting_t setting = store_and_clear_interrupt();
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queue->start = (queue->start + numToRemove) % queue->length;
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restore_interrupt_setting(setting);
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}
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