Ring Buffer

The Ring Buffer

A ring buffer (circular buffer) is the data structure at the heart of Linux pipes. It is a fixed-size array where write and read positions wrap around:

buf:  [ h | e | l | l | o |   |   |   ]
       ↑                   ↑
      head              tail
      (read here)      (write here)

• write: store byte at tail, advance tail = (tail + 1) % size
• read: load byte from head, advance head = (head + 1) % size
• full: count == size
• empty: count == 0

Your Implementation

#define RB_SIZE 8

typedef struct {
    char buf[RB_SIZE];
    int  head, tail, count;
} RingBuf;

int rb_write(RingBuf *rb, char c) {
    if (rb->count == RB_SIZE) return 0;
    rb->buf[rb->tail] = c;
    rb->tail = (rb->tail + 1) % RB_SIZE;
    rb->count++;
    return 1;
}

int rb_read(RingBuf *rb, char *c) {
    if (rb->count == 0) return 0;
    *c = rb->buf[rb->head];
    rb->head = (rb->head + 1) % RB_SIZE;
    rb->count--;
    return 1;
}

Your Task

Implement rb_write and rb_read. Also write rb_drain that reads and prints all remaining bytes.