sbuf.h

#ifndef __SBUF_H__
#define __SBUF_H__

#include "csapp.h"

typedef struct {
  int *buf;     /* Buffer array */
  int n;        /* Maximum number of slots */
  int front;    /* buf[(front+1)%n] is the first item */
  int rear;     /* buf[rear%n] is the last item */
  sem_t mutex;  /* Protects accesses to buf */
  sem_t slots;  /* Counts available slots */
  sem_t items;  /* Counts available items */
} sbuf_t;

void sbuf_init(sbuf_t *sp, int n);
void sbuf_deinit(sbuf_t *sp);
void sbuf_insert(sbuf_t *sp, int item);
int sbuf_remove(sbuf_t *sp);

#endif /* __SBUF_H__ */