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 #include "sLPC17xx.h"
  24 #include "platform_memory.h"
  25
  26 template <class T>
  27 class CircBuffer {
  28 public:
  29     CircBuffer(int length) {
  30         write = 0;
  31         read = 0;
  32         size = length;
  33         buf = (uint8_t*) AHB0.alloc(size * sizeof(T));
  34     };
  35
  36         bool isFull() {
  37                 return ((write + 1) % size == read);
  38     };
  39
  40     bool isEmpty() {
  41         return (read == write);
  42     };
  43
  44     void queue(T k) {
  45                 __disable_irq();
  46         if (isFull()) {
  47             read++;
  48             read %= size;
  49         }
  50         buf[write++] = k;
  51         write %= size;
  52                 __enable_irq();
  53     }
  54
  55     uint16_t available() {
  56                 __disable_irq();
  57                 uint16_t i= (write >= read) ? write - read : (size - read) + write;
  58                 __enable_irq();
  59                 return i;
  60     };
  61     uint16_t free() {
  62         return size - available() - 1;
  63     };
  64
  65     void dump() {
  66         iprintf("[RingBuffer Sz:%2d Rd:%2d Wr:%2d Av:%2d Fr:%2d]\n", size, read, write, available(), free());
  67     }
  68
  69     bool dequeue(T * c) {
  70         bool empty = isEmpty();
  71         if (!empty) {
  72             *c = buf[read++];
  73             read %= size;
  74         }
  75         return(!empty);
  76     };
  77
  78     void peek(T * c, int offset) {
  79         int h = (read + offset) % size;
  80         *c = buf[h];
  81     };
  82
  83     void flush() {
  84         read = write;
  85     }
  86
  87 private:
  88     volatile uint16_t write;
  89     volatile uint16_t read;
  90     uint16_t size;
  91     T * buf;
  92 };
  93
  94 #endif