common/queue.h

   1 /*
   2  * queue.h
   3 */
   4 #ifndef _QUEUE_H_
   5 #define _QUEUE_H_
   6 #include <stdint.h>
   7 #include <stdbool.h>
   8
   9 #define QUEUE_BASE_T    uint8_t
  10 #define QUEUE_INDEX_T   uint8_t
  11
  12 typedef volatile struct {
  13         QUEUE_BASE_T *restrict buffer;  // buffer
  14         QUEUE_INDEX_T first;    // position of first element
  15         QUEUE_INDEX_T last;     // position of last element (should be eliminated)
  16         QUEUE_INDEX_T ct;       //
  17         const QUEUE_INDEX_T sz; // size of the buffer
  18 } queue_t;
  19
  20 #define Q_DEF(buff) { .buffer = (buff), .first = 0, .last = 0, .ct = 0, .sz = sizeof(buff) / sizeof(QUEUE_BASE_T) }
  21
  22 // adds a new element
  23 int8_t q_push(queue_t *q, QUEUE_BASE_T x);
  24 int8_t q_push_o(queue_t *q, QUEUE_BASE_T x); // overwrites old data on q full
  25
  26 QUEUE_BASE_T q_pop(queue_t *q); // takes oldest element
  27 QUEUE_BASE_T q_remove(queue_t *q); // takes newest element
  28
  29 void q_flush(queue_t *q);
  30 bool q_empty(queue_t *q);
  31 bool q_full(queue_t *q);
  32
  33 #endif
  34