循环队列的实现

/*
 * =====================================================================================
 *
 * Filename: Queue.c
 *
 * Description:
 * Complete 4 interfaces for a circular queue:
 * 1) Whether it is an empty circular queue;
 * 2) Whether it is a full circular queue;
 * 3) Add data into circular queue;
 * 4) Remove data from circular queue.
 *
 * =====================================================================================
 */


#include <stdio.h>

#include <stdlib.h>

#include <string.h>



//****************************************************************************/

// Private Constants and Macros

//****************************************************************************/

#define TRUE 1

#define FALSE 0



//*************************************************/

// Private Type Definitions

//*************************************************/

typedef unsigned int UInt32;

typedef unsigned short UInt16;

typedef unsigned char UInt8;

typedef int Int32;

typedef short Int16;

typedef char Int8;

typedef char Bool;



//! Circular queue elements definition

typedef struct {
    UInt32 Front; // Front of queue

    UInt32 Rear; // Rear of queue

    UInt32 Count; // How many member in this queue

    UInt32 Data[QUEUE_SIZE]; // An arrary to store the queue data

}Queue_t;



/* Size of circular queue */

#define QUEUE_SIZE    5

/* Circular queue */

Queue_t Queue;



/**************************************************/

/*!

* \brief Initialize circular queue

*

* \iparam Q = which circular queue is going to be intialized

*

* \return Nothing

*

**************************************************/

void InitQueue(Queue_t *Q)

{

    Q->Front = 0;

    Q->Rear = 0;

    Q->Count = 0;

    memset(Q, 0, sizeof(Q->Data));

}



/**************************************************/

/*!

 * \brief To judge if it's an empty circular queue

 *

 * \iparam Q = which circular queue

 *

 * \return TURE(Empty queue) or FALSE (Not empty)

 *

 **************************************************/



Bool IsEmpty(Queue_t *Q) {

    if (Q->Count == 0) {

        printf("Queue is empty!\n");

        return TRUE;

    }

    else {

        return FALSE;

    }

}



/**************************************************/

/*!

 * \brief To judge if it's a full circular queue

 *

 * \iparam Q = which circular queue

 *

 * \return TURE(full queue) or FALSE (Not full)

 *

 **************************************************/

Bool IsFull(Queue_t *Q) {

    if (Q->Count == QUEUE_SIZE) {

        printf("Queue is full!\n");

        return TRUE;

    }

    else {

        return FALSE;

    }

}



/**************************************************/

/*!

* \brief Add a new data into circular queue

* If it's a full queue, it couldn't involve any data any more;

* If not, this data can be added in this queue.

*

* \iparam Q = which circular queue

* \iparam Data = A new data which is going to be added into

* the circular queue

*

* \return -1 (Fail to be added into queue)

* or 0 (Succeed to be added into queue)

*

**************************************************/

Int32 AddQueue(Queue_t *Q, UInt32 Data)
{
    if (IsFull(Q)) {

        return -1;

    }

    Q->Data[Q->Rear] = Data;

    Q->Rear = (Q->Rear + 1) % QUEUE_SIZE;

    Q->Count++;

    return 0;

}



/**************************************************/

/*!

* \brief Remove an existed data from circular queue

* If it's an empty queue, there is no data going to be

* removed. If not, an existed data will be removed from

* it successfully.

*

* \iparam Q = which circular queue

* \iparam *Data = the address where the data is going to
* be removed from queue
*

* \return -1 (Fail to be removed from queue)

* or 0 (Succeed to be removed from queue)

*

**************************************************/


Int32 RemoveQueue(Queue_t *Q, UInt32 *Data)

{
    if (IsEmpty(Q)) {

        return -1;

    }

    *Data = Q->Data[Q->Front];

    Q->Front = (Q->Front + 1) % QUEUE_SIZE;

    Q->Count--;

    return 0;

}