#include <pthread.h>
#include <unistd.h>
#define BUFSIZE 8
static int buffer[BUFSIZE];
static int bufin = 0;
static int bufout = 0;
static pthread_mutex_t
   buffer_lock = PTHREAD_MUTEX_INITIALIZER;
int get_buffersize(){
  return BUFSIZE;
}
void get_item(int *itemp){
   pthread_mutex_lock(&buffer_lock);
   *itemp = buffer[bufout];
   bufout = (bufout + 1) % BUFSIZE;
   pthread_mutex_unlock(&buffer_lock);
   return;
}
void put_item(int item){
   pthread_mutex_lock(&buffer_lock);
   buffer[bufin] = item;
   bufin = (bufin + 1) % BUFSIZE;
   pthread_mutex_unlock(&buffer_lock);
   return;
}