mqueue.h

#ifndef _EMERALD_MQUEUE_H
#define _EMERALD_MQUEUE_H
#include "assert.h"
#include "dist.h"
#include "types.h"

typedef struct {
  Node id;
  int length;
  void *msg;
} Message;

/*
 * MessageQueues are an queue of messages.
 * Operations:
 *	create, destroy, insert, remove, size, and print.
 */

/*
 * Hidden, private type declarations.  The only thing
 * that applications of this package are to see is MQueue,
 * and they are to treat it as opaque:  that is, they may
 * assign it, and pass it as arguments, but not manipulate
 * what it points to directly.
 */

typedef struct MQueueRecord {
    Message *table;
    int size, count, firstfull, firstempty;
} MQueueRecord, *MQueue;

/* OPERATIONS */

/* Return a new, empty Message Queue */
MQueue MQueueCreate(void);

/* Destroy a queue */
void MQueueDestroy(MQueue);

/* Insert the message into the queue q */
void MQueueInsert(MQueue q, Node id, int length, void *msg);

/* Remove the first element from the queue */
void MQueueRemove(MQueue q, Node *idp, int *lengthp, void **msgp);

/* DEBUGGING: Print the MQueue */
void MQueuePrint(MQueue q);

/* Return the number of elements in MQueue */
#define MQueueSize(MQueue) ((MQueue)->count)

#endif /* _EMERALD_MQUEUE_H */