git.zerfleddert.de Git - fnordlicht-mini/blob - firmware/fnordlicht-controller/fifo.c

   1 /* vim:ts=4 sts=4 et tw=80
   2  *
   3  *         fnordlicht firmware
   4  *
   5  *    for additional information please
   6  *    see http://lochraster.org/fnordlichtmini
   7  *
   8  * (c) by Alexander Neumann <alexander@bumpern.de>
   9  *     Lars Noschinski <lars@public.noschinski.de>
  10  *
  11  * This program is free software: you can redistribute it and/or modify it
  12  * under the terms of the GNU General Public License version 3 as published by
  13  * the Free Software Foundation.
  14  *
  15  * This program is distributed in the hope that it will be useful, but WITHOUT
  16  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  17  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  18  * more details.
  19  *
  20  * You should have received a copy of the GNU General Public License along with
  21  * this program.  If not, see <http://www.gnu.org/licenses/>.
  22  */
  23
  24 #include "fifo.h"
  25
  26 void fifo_init(fifo_t *f)
  27 {
  28     f->read = 0;
  29     f->write = 0;
  30 }
  31
  32 void fifo_enqueue(fifo_t *f, fifo_content_t data)
  33 {
  34     f->buffer[f->write] = data;
  35     f->write = (f->write + 1) % CONFIG_FIFO_SIZE;
  36 }
  37
  38 fifo_content_t fifo_dequeue(fifo_t *f)
  39 {
  40     fifo_content_t data = f->buffer[f->read];
  41     f->read = (f->read + 1) % CONFIG_FIFO_SIZE;
  42     return data;
  43 }
  44
  45 fifo_size_t fifo_fill(fifo_t *f)
  46 {
  47     if (f->write >= f->read)
  48         return f->write - f->read;
  49     else
  50         return CONFIG_FIFO_SIZE - (f->read - f->write);
  51 }
  52
  53 bool fifo_empty(fifo_t *f)
  54 {
  55     return f->read == f->write;
  56 }
  57
  58 bool fifo_full(fifo_t *f)
  59 {
  60     return fifo_fill(f) == CONFIG_FIFO_SIZE-1;
  61 }