avr/msgbuffer.c

   1 /*
   2  * Copyright (C) 2007 Anton Blad
   3  * Copyright (C) 2007 Fredrik Kuivinen
   4  * Copyright (C) 2007 Jakob Rosén
   5  *
   6  * This file is licensed under GPL v2.
   7  */
   8
   9 #include "msgbuffer.h"
  10
  11 uint8_t msgbuffer[MSGBUFFER_CAPACITY];
  12 uint8_t msgbuffer_start = 0;
  13 uint8_t msgbuffer_size = 0;
  14
  15 void msgbuffer_addbyte(uint8_t a)
  16 {
  17         uint8_t idx;
  18
  19         if(msgbuffer_size < MSGBUFFER_CAPACITY)
  20         {
  21                 idx = msgbuffer_start+msgbuffer_size;
  22                 if(idx >= MSGBUFFER_CAPACITY)
  23                         idx -= MSGBUFFER_CAPACITY;
  24
  25                 msgbuffer[idx] = a;
  26                 msgbuffer_size++;
  27         }
  28 }
  29
  30 uint8_t msgbuffer_getbyte()
  31 {
  32         uint8_t a = 0xff;
  33
  34         if(msgbuffer_size > 0)
  35         {
  36                 a = msgbuffer[msgbuffer_start];
  37
  38                 msgbuffer_size--;
  39                 msgbuffer_start++;
  40                 if(msgbuffer_start >= MSGBUFFER_CAPACITY)
  41                         msgbuffer_start = 0;
  42         }
  43
  44         return a;
  45 }