#include <stdint.h>
#include <stddef.h>
#include "rbuf.h"

int32_t rbuf_push(RBuf *rbuf, uint8_t data) {
  size_t next;

  next = rbuf->head + 1;
  if (next >= rbuf->cap) {
    next = 0;
  }

  if (next == rbuf->tail) {
    return -1;
  }

  rbuf->buffer[rbuf->head] = data;
  rbuf->head = next;
  return 0;
}

int32_t rbuf_pop(RBuf *rbuf, uint8_t *data) {
  size_t next;

  if (rbuf->head == rbuf->tail) {
    return -1;
  }

  next = rbuf->tail + 1;
  if (next >= rbuf->cap) {
    next = 0;
  }

  *data = rbuf->buffer[rbuf->tail];
  rbuf->tail = next;
  return 0;
}