midi

protocol/lufa/midi/bytequeue/bytequeue.c

@@ -0,0 +1,65 @@
+//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);
+}
+