102 lines
2.4 KiB
C
102 lines
2.4 KiB
C
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/*
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* File: queue.h
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* Author: Robert I. Pitts <rip@cs.bu.edu>
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* Last Modified: March 9, 2000
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* Topic: Queue - Array Implementation
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* ----------------------------------------------------------------
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*/
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#ifndef _QUEUE_H
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#define _QUEUE_H
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/*
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* Constants
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* ---------
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* ERROR_* These signal error conditions in queue functions
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* and are used as exit codes for the program.
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*/
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#define ERROR_QUEUE 2
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#define ERROR_MEMORY 3
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/*
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* Type: queueElementT
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* -------------------
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* This is the type of objects held in the queue.
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*/
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/*typedef char queueElementT;
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typedef unsigned char *queueElementT;
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*/
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struct queuepacket{
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int len;
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unsigned char data[2000];
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};
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typedef struct queuepacket *queueElementT;
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/*
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* Type: queueADT
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* --------------
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* The actual implementation of a queue is completely
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* hidden. Client will work with queueADT which is a
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* pointer to underlying queueCDT.
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*/
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/*
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* NOTE: need word struct below so that the compiler
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* knows at least that a queueCDT will be some sort
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* of struct.
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*/
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typedef struct queueCDT *queueADT;
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/*
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* Function: QueueCreate
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* Usage: queue = QueueCreate();
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* -------------------------
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* A new empty queue is created and returned.
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*/
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queueADT QueueCreate(void);
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/* Function: QueueDestroy
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* Usage: QueueDestroy(queue);
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* -----------------------
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* This function frees all memory associated with
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* the queue. "queue" may not be used again unless
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* queue = QueueCreate() is called first.
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*/
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void QueueDestroy(queueADT queue);
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/*
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* Functions: QueueEnter, QueueDelete
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* Usage: QueueEnter(queue, element);
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* element = QueueDelete(queue);
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* --------------------------------------------
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* These are the fundamental queue operations that enter
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* elements in and delete elements from the queue. A call
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* to QueueDelete() on an empty queue or to QueueEnter()
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* on a full queue is an error. Make use of QueueIsFull()
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* and QueueIsEmpty() (see below) to avoid these errors.
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*/
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void QueueEnter(queueADT queue, queueElementT element);
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queueElementT QueueDelete(queueADT queue);
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/*
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* Functions: QueueIsEmpty, QueueIsFull
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* Usage: if (QueueIsEmpty(queue)) ...
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* -----------------------------------
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* These return a true/false value based on whether
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* the queue is empty or full, respectively.
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*/
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int QueueIsEmpty(queueADT queue);
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int QueueIsFull(queueADT queue);
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int QueuePeek(queueADT queue);
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#endif /* not defined _QUEUE_H */
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