tmk_core/tool/mbed/mbed-sdk/libraries/USBDevice/USBSerial/CircBuffer.h

   1 /* Copyright (c) 2010-2011 mbed.org, MIT License
   2 *
   3 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
   4 * and associated documentation files (the "Software"), to deal in the Software without
   5 * restriction, including without limitation the rights to use, copy, modify, merge, publish,
   6 * distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the
   7 * Software is furnished to do so, subject to the following conditions:
   8 *
   9 * The above copyright notice and this permission notice shall be included in all copies or
  10 * substantial portions of the Software.
  11 *
  12 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
  13 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  14 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
  15 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  16 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  17 */
  18
  19 #ifndef CIRCBUFFER_H
  20 #define CIRCBUFFER_H
  21
  22 template <class T, int Size>
  23 class CircBuffer {
  24 public:
  25     CircBuffer():write(0), read(0){}
  26     bool isFull() {
  27         return ((write + 1) % size == read);
  28     };
  29
  30     bool isEmpty() {
  31         return (read == write);
  32     };
  33
  34     void queue(T k) {
  35         if (isFull()) {
  36             read++;
  37             read %= size;
  38         }
  39         buf[write++] = k;
  40         write %= size;
  41     }
  42
  43     uint16_t available() {
  44         return (write >= read) ? write - read : size - read + write;
  45     };
  46
  47     bool dequeue(T * c) {
  48         bool empty = isEmpty();
  49         if (!empty) {
  50             *c = buf[read++];
  51             read %= size;
  52         }
  53         return(!empty);
  54     };
  55
  56 private:
  57     volatile uint16_t write;
  58     volatile uint16_t read;
  59     static const int size = Size+1;  //a modern optimizer should be able to remove this so it uses no ram.
  60     T buf[Size];
  61 };
  62
  63 #endif