使用链表管理内存

淡淡的烟草味﹌ 2022-09-24 08:27 134阅读 0赞

使用链表管理内存的使用，这儿重新定义了 malloc,realloc,free函数，使用了mymalloc,myrealloc,myfree自己重定义了函数

mem.h

#include<stdio.h>
    #include<stdlib.h>
    
    
    void * mymalloc(size_t size);
    void *myrealloc(void *p, size_t size);
    void myfree(void *p);
    
    struct mem
    {
    	void *p;	//内存地址
    	int size;	//内存大小
    };
    
    struct LinkNode
    {
    	struct mem *pmem;	//保存指针
    	struct LinkNode *pNext; //指向下一个节点
    };
    
    typedef struct LinkNode node, *PNODE;
    
    struct LinkNode *phead;
    
    PNODE addNode(PNODE phead, struct mem *pmem);	//增加
    PNODE changNode(PNODE phead, void *findaddr, struct mem *pmem);	//修改
    PNODE deleteNode(PNODE phead, void * find);	//删除
    void showAll(PNODE phead);	//显示所节点
    void getInfo(PNODE phead);	//显示详细信息
    PNODE deleteAll(PNODE phead);	//清除所有所使用的内存
    PNODE findNode(PNODE phead, void *p);	//查询

mem.c

#include"eme.h"
    
    void * mymalloc(size_t size)
    {
    	void *p = malloc(size);
    	struct mem *pmem = malloc(sizeof(struct mem));
    	pmem->p = p;
    	pmem->size = size;
    	phead = addNode(phead, pmem);
    
    	return p;
    }
    
    void *myrealloc(void *p, size_t size)
    {
    	void *pt = realloc(p, size);
    	struct mem pmem;//这儿是不需要在堆上开辟，因为只是个赋值，链表上的地址不需要修改。
    	pmem.p = pt;
    	pmem.size = size;
    	phead = changNode(phead, p, &pmem);
    	return pt;
    }
    
    void myfree(void *p)
    {
    	PNODE ptemp = findNode(phead, p);
    	if (ptemp)
    	{
    		phead = deleteNode(phead, p);
    		free(p);
    	}
    		
    	else
    	{
    		printf("没有内存需要释放！\n");
    	}
    }
    
    PNODE addNode(PNODE phead, struct mem *pmem)	//增加
    {
    	PNODE pnew = malloc(sizeof(node));
    	pnew->pmem = pmem;
    	
    	pnew->pNext = NULL;
    
    	if (phead == NULL)
    	{
    		phead = pnew;
    	}
    	else
    	{
    		PNODE ptemp = phead;
    		while (ptemp->pNext != NULL)
    		{
    			ptemp = ptemp->pNext;
    		}
    		ptemp->pNext = pnew;
    	}
    	return phead;
    }
    
    PNODE changNode(PNODE phead, void *findaddr, struct mem *pmem)	//修改
    {
    	//因为修改是对原料来数据进行的改动，所以不用再分配地址
    	//修改要先查询一下，有没有相应的数据，如果没有则不会进行修改
    	PNODE ptemp = findNode(phead, findaddr);
    	if (ptemp == NULL)
    	{
    		printf("没有查询到要修改的地址！\n");
    		return phead;
    	}
    	else
    	{
    	
    		for (PNODE ptemp = phead; ptemp != NULL;ptemp=ptemp->pNext)
    		{
    			if (ptemp->pmem->p == findaddr)
    			{
    				ptemp->pmem->p = pmem->p;
    				ptemp->pmem->size = pmem->size;
    				return phead;
    			}
    		}
    		
    	}
    	return phead;
    }
    
    PNODE deleteNode(PNODE phead, void * find)	//删除
    {
    	PNODE p1 = NULL;
    	PNODE p2 = NULL;
    	p1 = phead;
    	//这儿不没有使用查询，是因为在调前（myfree())时就查询了，如果没有就直接返回
    	while (p1 != NULL)
    	{
    		if (p1->pmem->p == find)
    		{
    			break;
    		}
    		else
    		{
    			p2 = p1;
    			p1 = p1->pNext;
    		}
    	}
    	if (p1 == phead)
    	{
    		phead = p1->pNext;
    		free(p1->pmem);	//释放链表所占用的内存空间
    		free(p1);
    	}
    	else
    	{
    		p2->pNext = p1->pNext;
    		free(p1->pmem);	//释放链表所占用的内存空间
    		free(p1);
    	}
    
    	return phead;
    }
    
    void showAll(PNODE phead)	//显示所节点
    {
    	if (phead == NULL)
    	{
    		return;
    	}
    	else
    	{
    		PNODE ptemp = phead;
    		while (ptemp != NULL)
    		{
    			printf("%p %d\n", ptemp->pmem->p, ptemp->pmem->size);
    			ptemp = ptemp->pNext;
    		}
    	}
    }
    
    
    PNODE deleteAll(PNODE phead)	//清除所有所使用的内存
    {
    	if (phead == NULL)
    	{
    		return phead;
    	}
    	else
    	{
    		printf("开始清理使用的内存......\n");
    		PNODE p1 = NULL;
    		PNODE p2 = NULL;
    		p1 = phead;
    		while (p1->pNext != NULL)
    		{
    			p2 = p1->pNext;
    			p1->pNext = p2->pNext;
    			free(p2->pmem->p);
    			free(p2->pmem);
    			free(p2);
    		}
    		//删除头节点
    		free(phead->pmem->p);
    		free(phead->pmem);
    		free(phead);
    		phead = NULL;
    		printf("使用的内存被清空......\n");
    	
    	}
    	return phead;
    }
    
    
    PNODE findNode(PNODE phead, void *p)	//查询
    {
    	for (PNODE ptemp = phead; ptemp != NULL; ptemp = ptemp->pNext)
    	{
    		if (ptemp->pmem->p == p)
    		{
    			return ptemp;
    		}
    	}
    
    	return	NULL;
    
    
    }
    void getInfo(PNODE phead)	//显示详细信息
    {
    	int i = 0;
    	int j = 0;
    	for (PNODE ptemp = phead; ptemp != NULL; ptemp = ptemp->pNext)
    	{
    		i++;
    		j += ptemp->pmem->size;
    	}
    	printf("有 %d 片内存在使用中， 使用的内存地址大小为 %d k\n",i,j/1024);
    	
    }

main.c

#include"eme.h"
    
    #define malloc mymalloc
    #define realloc myrealloc
    #define free myfree
    
    
    void main()
    {
    	void *p1 = malloc(10);
    	void *p2 = malloc(11);
    	void *p3 = malloc(12);
    	void *p4 = malloc(13);
    
    	
    	printf("\n\n");
    	showAll(phead);
    	
    	p1 = realloc(p1, 10000);
    	p2 = realloc(p2, 1000000);
    	printf("\n\n");
    	showAll(phead);
    
    	getInfo(phead);
    	//free(p2);
    	//free(p2);
    	//printf("\n\n");
    	//showAll(phead);
    
    	//free(p1);
    
    	//printf("\n\n");
    	//showAll(phead);
    	
    	phead = deleteAll(phead);
    
    	getInfo(phead);
    	printf("\n\n");
    	showAll(phead);
    
    
    	system("pause");
    }