list/queue/sqqueue.c

#include <stdio.h>
#include <stdlib.h>
#include "sqqueue.h"

queue_t pkt_creat_sqqueue(int len)
{
    queue_t q;
    if ((q = (queue_t)malloc(sizeof(struct queue))) == NULL)
    {
        printf("malloc failed!\n");
        return NULL;
    }

    if ((q->msg = (message_t)malloc(sizeof(struct message) * len)) == NULL)
    {
        printf("malloc failed!\n");
        return NULL;
    }

    q->front = q->rear = len - 1;
    q->len = len;
    return q;
}

int pkt_empty_sqqueue(queue_t q)
{
    return q->front == q->rear;
}

int pkt_full_sqqueue(queue_t q)
{
    return (q->rear + 1) % q->len == q->front;  /* 空出一个消息位置判断为满，队列最大装len - 1个 */
}

int pkt_put_message_sqqueue(queue_t q, message_t m)
{
    if (pkt_full_sqqueue(q))
    {
        printf("squeue is full!\n");
        return -1; 
    }

    q->rear = (q->rear + 1) % q->len; /* first rear++ */
    q->msg[q->rear] = *m;
    return 0;
}

int pkt_take_message_sqqueue(queue_t q, message_t m)
{
    if (pkt_empty_sqqueue(q))
    {
        printf("squeue is empty!\n");
        return -1;
    }

    q->front = (q->front + 1) % q->len; /* frist front++ */
    *m = q->msg[q->front];
    return 0;
}

int pkt_show_sqqueue(queue_t q)
{
    int i;
    for (i = (q->front + 1) % q->len; i != (q->rear + 1) % q->len; i = (i + 1) % q->len)
    {
        printf("queue[%d] = %d\n", i, q->msg[i].data);
    }

    return 0;
}

int main(int argc, char **argv)
{
    queue_t q;

    q = pkt_creat_sqqueue(10);

    struct message m;
    for (int i = 1; i <= 10; i++)
    {
        m.data = i;
        printf("put %d\n", m.data);
        pkt_put_message_sqqueue(q, &m);
    }

    while (!pkt_empty_sqqueue(q))
    {
        pkt_take_message_sqqueue(q, &m);
        printf("take = %d\n", m.data);
    }

    pkt_show_sqqueue(q);

    return 0;
}