Implement RingBuffer

V0: basic init with given backing up buffer, reject to enqueue if full(no override), support dequeue

#include <limits.h>

typedef struct {
    int *buffer;
    int head; //index of the next element to read, oldest
    int tail; // tail is the index where the next write will go (one past the newest item)
    int capacity;
    int count;
} ring_buffer_t;


void init(ring_buffer_t *rb, int *backing, int capacity){
    rb->buffer = backing;
    rb->head=0;
    rb->tail=0;
    rb->capacity=capacity;
    rb->count=0;
}
 
void enqueue(ring_buffer_t *rb, int val){
    if (rb->count == rb->capacity){
        // Full, reject
        return;
    }
    // Write at current tail, then advance with wrap-around
    rb->buffer[rb->tail] = val;
    rb->tail = (rb->tail + 1) % rb->capacity;
    rb->count++;
}

int dequeue(ring_buffer_t *rb){
    //if empty
    if (rb->count == 0){
        return INT_MIN;
    }
    int value = rb->buffer[rb->head];
    // needs to wrap around 
    rb->head = (rb->head + 1) % rb->capacity;
    rb->count--;
    return value;
}