src/libs/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 #include <stdlib.h>
  23
  24 template <class T>
  25 class CircBuffer {
  26 public:
  27     CircBuffer(int length) {
  28         write = 0;
  29         read = 0;
  30         size = length + 1;
  31         buf = (T *)malloc(size * sizeof(T));
  32     };
  33
  34     bool isFull() {
  35         return ((write + 1) % size == read);
  36     };
  37
  38     bool isEmpty() {
  39         return (read == write);
  40     };
  41
  42     void queue(T k) {
  43         if (isFull()) {
  44             read++;
  45             read %= size;
  46         }
  47         buf[write++] = k;
  48         write %= size;
  49     }
  50
  51     uint16_t available() {
  52         return (write >= read) ? write - read : (size - read) + write;
  53     };
  54     uint16_t free() {
  55         return size - available();
  56     };
  57
  58     void dump() {
  59         iprintf("[RingBuffer Sz:%2d Rd:%2d Wr:%2d Av:%2d Fr:%2d]\n", size, read, write, available(), free());
  60     }
  61
  62     bool dequeue(T * c) {
  63         bool empty = isEmpty();
  64         if (!empty) {
  65             *c = buf[read++];
  66             read %= size;
  67         }
  68         return(!empty);
  69     };
  70
  71     void flush() {
  72         read = write;
  73     }
  74
  75 private:
  76     volatile uint16_t write;
  77     volatile uint16_t read;
  78     uint16_t size;
  79     T * buf;
  80 };
  81
  82 #endif