CircBuffer.h

00001 /* Copyright (c) 2010-2011 mbed.org, MIT License
00002 *
00003 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
00004 * and associated documentation files (the "Software"), to deal in the Software without
00005 * restriction, including without limitation the rights to use, copy, modify, merge, publish,
00006 * distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the
00007 * Software is furnished to do so, subject to the following conditions:
00008 *
00009 * The above copyright notice and this permission notice shall be included in all copies or
00010 * substantial portions of the Software.
00011 *
00012 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
00013 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00014 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
00015 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00016 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00017 */
00018 
00019 #ifndef CIRCBUFFER_H
00020 #define CIRCBUFFER_H
00021 
00022 template <class T, int Size>
00023 class CircBuffer {
00024 public:
00025     CircBuffer():write(0), read(0){}
00026     bool isFull() {
00027         return ((write + 1) % size == read);
00028     };
00029 
00030     bool isEmpty() {
00031         return (read == write);
00032     };
00033 
00034     void queue(T k) {
00035         if (isFull()) {
00036             read++;
00037             read %= size;
00038         }
00039         buf[write++] = k;
00040         write %= size;
00041     }
00042 
00043     uint16_t available() {
00044         return (write >= read) ? write - read : size - read + write;
00045     };
00046 
00047     bool dequeue(T * c) {
00048         bool empty = isEmpty();
00049         if (!empty) {
00050             *c = buf[read++];
00051             read %= size;
00052         }
00053         return(!empty);
00054     };
00055 
00056 private:
00057     volatile uint16_t write;
00058     volatile uint16_t read;
00059     static const int size = Size+1;  //a modern optimizer should be able to remove this so it uses no ram.
00060     T buf[Size+1];
00061 };
00062 
00063 #endif