队列-C语言-链表的实现方式

前言： 此代码可动态的构建内存队列，当队列长度达到最大长度（MAXLEN ），ac_adjust_queue函数会删除队列中无效的内存。

1、头文件 linkqueue.h

#ifndef _MEM_LINK_H#define _MEM_LINK_H#include <stdio.h>#include <stdlib.h>#define OK 1#define ERROR -1#define TRUE 1#define FALSE 0#define OVERMEM -2#define MAXLEN  3typedef struct FrameInfo{unsigned int width;unsigned int height;unsigned int istate;unsigned char* memry;}FrameInfo;typedef FrameInfo ElemType;typedef struct LinkNode {ElemType data;struct LinkNode *next;}LinkNode, *LinkNodePtr;typedef struct {LinkNodePtr front;LinkNodePtr rear;}LinkQueue;int ac_init_queue(LinkQueue *Q);int av_clear_queue(LinkQueue *Q);int ac_destroy_queue(LinkQueue *Q);int ac_queue_empty(LinkQueue Q);int ac_queue_lenth(LinkQueue Q);int ac_adjust_queue(LinkQueue *Q);int ac_get_head(LinkQueue Q, ElemType *e);int ac_get_ready(LinkQueue Q, ElemType **e);int ac_entry_queue(LinkQueue *Q, ElemType *e);int ac_out_queue(LinkQueue *Q, ElemType *e);#endif

2、相应的实现文件 linkqueue.c

#include <string.h>#include "linkqueue.h"/*初始化队列（链表）*/int ac_init_queue(LinkQueue *Q) {//initiate an empty queueQ->front = Q->rear = (LinkNodePtr)malloc(sizeof(LinkNode));if (!Q->front)return OVERMEM;Q->front->next = NULL;return OK;}/*清空队列*/int av_clear_queue(LinkQueue *Q) {//clear an exitstd queueif (Q->front == NULL)return ERROR;LinkNodePtr p, q;Q->rear = Q->front;p = Q->front->next;Q->front->next = NULL;while (p) {q = p;p = p->next;free(q);}return OK;}/*销毁队列*/int ac_destroy_queue(LinkQueue *Q) {//destroy an existed queueif (Q->front == NULL)return ERROR;while (Q->front) {Q->rear = Q->front->next;free(Q->front);Q->front = Q->rear;}return OK;}/*判断队列是否为空*/int ac_queue_empty(LinkQueue Q) {//whether the queue is emptyif (Q.front == NULL)return ERROR;else if (Q.front->next == NULL)return TRUE;elsereturn FALSE;}/*获取队列的长度*/int ac_queue_lenth(LinkQueue Q) {//get the length of the queueif (Q.front == NULL)return ERROR;int len = 0;LinkNodePtr p;p = Q.front;while (p != Q.rear) {len++;p = p->next;}return len;}/*调整队列，删除队列中不合要求的元素*/int ac_adjust_queue(LinkQueue *Q){LinkNodePtr ptr;LinkNodePtr curptr, preptr;int iwidth, iheight, idx, ix, noest;int imaxc = 0, imaxidxco = 0;int iPw[MAXLEN] = { 0, 0 }, iPh[MAXLEN] = { 0, 0 }, iPc[MAXLEN] = {0, 0};ptr = Q->front;if (ac_queue_lenth(*Q) >= MAXLEN){//统计开辟的内存中，宽与高组合的概率ix = 0, noest = 0;while (ptr != Q->rear){ptr = ptr->next;if (ptr != NULL){iwidth = ptr->data.width;iheight = ptr->data.height;for (idx = 0; idx < MAXLEN; idx++){if (iPw[idx] == iwidth && iPh[idx] == iheight){iPc[idx]++;noest = 0;break;}else{noest = 1;}}if (idx == MAXLEN && noest == 1){iPw[ix] = iwidth;iPh[ix] = iheight;iPc[ix]++;ix++;}}}//寻找出现次数最多的宽高组合for (idx = 0; idx < MAXLEN; idx++){if (iPc[idx] > imaxc){imaxc = iPc[idx];imaxidxco = idx;}}//调整队列链表,删除不合要求的内存//LinkNodePtr curptr, preptr;/*curptr = Q.front->next;if (curptr->data.width != iPw[imaxidxco] || ptr->data.height != iPh[imaxidxco]){Q.front->next = curptr->next;free(curptr);}*/preptr = Q->front;curptr = preptr->next;while (curptr != NULL){if (curptr->data.width != iPw[imaxidxco] || curptr->data.height != iPh[imaxidxco]){preptr->next = curptr->next;free(curptr->data.memry);free(curptr);curptr = preptr->next;}else{preptr = curptr;curptr = preptr->next;}}}return 0;}/*获取队列头元素*/int ac_get_head(LinkQueue Q, ElemType *e) {//get the head element of the queueif (Q.front == Q.rear)return ERROR;*e = Q.front->next->data;return OK;}/*获取队列中可用的元素*/int ac_get_ready(LinkQueue Q, ElemType **e){LinkNodePtr ptr;if (Q.front == NULL)return ERROR;ptr = Q.front;while (ptr != Q.rear ){ptr = ptr->next;if (ptr->data.istate == 0)break;}if (ptr != Q.rear || ptr->data.istate == 0){*e = &ptr->data;return OK;}else{return FALSE;}}/*元素入队列*/int ac_entry_queue(LinkQueue *Q, ElemType *e) {//input an element e as the new rear of the queueLinkNodePtr p;p = (LinkNodePtr)malloc(sizeof(LinkNode));if (!p)return OVERMEM;p->data.memry = e->memry;//(unsigned char*)malloc(e.width * e.height * sizeof(unsigned char));p->data.width = e->width;p->data.height = e->height;p->data.istate = e->istate;p->next = NULL;Q->rear->next = p;Q->rear = p;return OK;}/*元素出队列*/int ac_out_queue(LinkQueue *Q, ElemType *e) {//delete an element which was the head of the queueif (Q->front == Q->rear)return ERROR;LinkNodePtr p;p = Q->front->next;*e = p->data;Q->front->next = p->next;if (Q->rear == p)Q->rear = Q->front;free(p);return OK;}

3、主函数main.c

#include "linkqueue.h"int main() {ElemType in;ElemType *ot = NULL;LinkQueue *q1 = (LinkQueue*)malloc(sizeof(LinkQueue));ac_init_queue(q1);GETMEM:if (ac_queue_empty(*q1) == 1){in.width = 1281;in.height = 720;in.istate = 1;in.memry = (unsigned char*)malloc(in.width * in.height * sizeof(unsigned char));memset(in.memry, 0, in.width * in.height);ac_entry_queue(q1, &in);}else{if (ac_get_ready(*q1, &ot) != 1)//队列中无可用内存{in.width = 1280;in.height = 720;in.istate = 1;in.memry = (unsigned char*)malloc(in.width * in.height * sizeof(unsigned char));ac_entry_queue(q1, &in);}}in.width = 1280;in.height = 721;in.istate = 0;in.memry = (unsigned char*)malloc(in.width * in.height * sizeof(unsigned char));ac_entry_queue(q1, &in);in.width = 1280;in.height = 720;in.istate = 0;in.memry = (unsigned char*)malloc(in.width * in.height * sizeof(unsigned char));ac_entry_queue(q1, &in);ac_adjust_queue(q1);if (ac_get_ready(*q1, &ot) != 1){printf("can not get memory!\n");return ERROR;}if (ot->width != 1280 || ot->height != 720){ot->istate = 2;goto GETMEM;}return 0;}

参考网址：http://blog.csdn.net/went2011/article/details/6929509