Ring buffer in C, push to tail, pop from head, single size define <=256

ring.c

#include <stdbool.h> // bool, required
#include <stdio.h>   // printf, only for debug
#include <stdlib.h>  // uint8_t, required
#include <string.h>  // memset, required

#define RING_BUFFER_SIZE 4
#if RING_BUFFER_SIZE > 256
#error "RING_BUFFER_SIZE must be <=256"
#endif

typedef struct {
  uint8_t data[RING_BUFFER_SIZE];
  uint8_t head;
  uint8_t tail;
  bool over;
} RingBuffer_t;

void Ring_Init(RingBuffer_t* const b) {
  memset(b->data, 0, RING_BUFFER_SIZE);
  b->head = 0;
  b->tail = 0;
  b->over = false;
}

bool Ring_PushTail(RingBuffer_t* const b, uint8_t value) {
  if (b->over && (b->tail == b->head)) {
    printf("ring push(%c)  ERR over\n", value);
    return false;
  }
  uint8_t next = (b->tail + 1) % RING_BUFFER_SIZE;
  if (next == b->head) {
    b->over = true;
  }
  b->data[b->tail] = value;
  b->tail = next;
  printf("ring push(%c)  head=%d tail=%d next=%d over=%d\n", value, b->head,
         b->tail, next, b->over);
  return true;
}

bool Ring_PopHead(RingBuffer_t* const b, uint8_t* const out) {
  if (!b->over && (b->tail == b->head)) {
    printf("ring pop      ERR empty head=%d tail=%d over=%d\n", b->head, b->tail,
           b->over);
    return false;
  }
  uint8_t next = (b->head + 1) % RING_BUFFER_SIZE;
  *out = b->data[b->head];
  // b->data[b->head] = 0;
  b->head = next;
  b->over = false;
  printf("ring pop      out=%c head=%d tail=%d over=%d\n", *out, b->head,
         b->tail, b->over);
  return true;
}

void Ring_Debug(RingBuffer_t const* const b) {
  printf("ring debug    data=[%c%c%c%c] head=%d tail=%d over=%d content=[",
         b->data[0]!=0?b->data[0]:'.',
         b->data[1]!=0?b->data[1]:'.',
         b->data[2]!=0?b->data[2]:'.',
         b->data[3]!=0?b->data[3]:'.',
         b->head, b->tail, b->over);
  uint8_t h = b->head, t = b->tail, n = t - h;
  if (b->over && (h == t)) {
    n = RING_BUFFER_SIZE;
  } else if (h > t) {
    n = RING_BUFFER_SIZE - h + t;
  }
  for (uint8_t i = 0; i < n; i++) {
    uint8_t j = (h + i) % RING_BUFFER_SIZE;
    printf("%c", b->data[j]);
  }
  printf("]\n");
}

int main() {
  RingBuffer_t rb;
  uint8_t v;
  Ring_Init(&rb);
  Ring_Debug(&rb);
  Ring_PushTail(&rb, '1');
  Ring_Debug(&rb);
  Ring_PushTail(&rb, '2');
  Ring_Debug(&rb);
  Ring_PushTail(&rb, 't');
  Ring_Debug(&rb);
  Ring_PopHead(&rb, &v);
  Ring_Debug(&rb);
  Ring_PushTail(&rb, '3');
  Ring_Debug(&rb);
  Ring_PushTail(&rb, '4');
  Ring_Debug(&rb);
  Ring_PushTail(&rb, 'e');
  Ring_Debug(&rb);
  Ring_PopHead(&rb, &v);
  Ring_Debug(&rb);
  Ring_PopHead(&rb, &v);
  Ring_Debug(&rb);
  Ring_PopHead(&rb, &v);
  Ring_Debug(&rb);
  Ring_PopHead(&rb, &v);
  Ring_Debug(&rb);
  Ring_PopHead(&rb, &v);
  Ring_Debug(&rb);
  return 0;
}