操作系统内存管理实验（C语言实现）

#include<stdio.h> #include<stdlib.h> #define OK 1 //完成 #define ERROR 0 //出错 typedef int Status; typedef struct free_table//定义一个空闲区说明表结构 { int num; //分区序号 long address; //起始地址 long length;//分区大小 int state; //分区状态 }ElemType; typedef struct Node//线性表的双向链表存储结构 { ElemType data; struct Node*prior;//前趋指针 struct Node *next;//后继指针 }Node,*LinkList; LinkList first;//头结点 LinkList end;//尾结点 int flag;//记录要删除的分区序号 Status Initblock()//开创带头结点的内存空间链表 { first=(LinkList)malloc(sizeof(Node)); end=(LinkList)malloc(sizeof(Node)); first->prior=NULL; first->next=end; end->prior=first; end->next=NULL; end->data.num=1; end->data.address=40; end->data.length=600; end->data.state=0; return OK; } void sort()//分区序号重新排序 { Node *p=first->next,*q; q=p->next; for(;p!=NULL;p=p->next) { for(q=p->next;q;q=q->next) { if(p->data.num>=q->data.num) { q->data.num+=1; } } } } void show()//显示主存分配情况 { int flag=0;//用来记录分区序号 Node *p=first; p->data.num=0; p->data.address=0; p->data.length=40; p->data.state=1; sort(); printf("\n\t\t》主存空间分配情况《\n"); printf("**********************************************************\n\n"); printf("分区序号\t起始地址\t分区大小\t分区状态\n\n"); while(p) { printf("%d\t\t%d\t\t%d",p->data.num,p->data.address,p->data.length); if(p->data.state==0) printf("\t\t空闲\n\n"); else printf("\t\t已分配\n\n"); p=p->next; } printf("**********************************************************\n\n"); } Status First_fit(int request) {//首次适应算法 Node *p=first->next;//为申请作业开辟新空间且初始化 LinkList temp=(LinkList)malloc(sizeof(Node)); temp->data.length=request; temp->data.state=1; p->data.num=1; while(p) { if((p->data.state==0)&&(p->data.length==request)) {//有大小恰好合适的空闲块 p->data.state=1; return OK; break; } else if((p->data.state==0) && (p->data.length>request)) {//有空闲块能满足需求且有剩余 temp->prior=p->prior; temp->next=p; temp->data.address=p->data.address; temp->data.num=p->data.num; p->prior->next=temp; p->prior=temp; p->data.address=temp->data.address+temp->data.length; p->data.length-=request; p->data.num+=1; return OK; break; } p=p->next; } return ERROR; } Status Best_fit(int request)//最佳适应算法 { int ch;//记录最小剩余空间 Node *p=first; Node *q=NULL;//记录最佳插入位置 LinkList temp=(LinkList)malloc(sizeof(Node)); temp->data.length=request; temp->data.state=1; p->data.num=1; while(p)//初始化最小空间和最佳位置 { if((p->data.state==0) && (p->data.length>=request) ) { if(q==NULL) { q=p; ch=p->data.length-request; } else if(q->data.length > p->data.length) { q=p; ch=p->data.length-request; } } p=p->next; } if(q==NULL) return ERROR; //没有找到空闲块 else if(q->data.length==request) { q->data.state=1; return OK; } else { temp->prior=q->prior; temp->next=q; temp->data.address=q->data.address; temp->data.num=q->data.num; q->prior->next=temp; q->prior=temp; q->data.address+=request; q->data.length=ch; q->data.num+=1; return OK; } return OK; } Status Worst_fit(int request) //最差适应算法 { int ch;//记录最大剩余空间 Node *p=first->next; Node *q=NULL;//记录最佳插入位置 LinkList temp=(LinkList)malloc(sizeof(Node)); temp->data.length=request; temp->data.state=1; p->data.num=1; while(p)//初始化最大空间和最佳位置 { if(p->data.state==0 && (p->data.length>=request) ) { if(q==NULL) { q=p; ch=p->data.length-request; }else if(q->data.length<p->data.length) { q=p; ch=p->data.length-request; } } p=p->next; } if(q==NULL) return ERROR;//没有找到空闲块 else if(q->data.length==request) { q->data.length=1; return OK; }else { temp->prior=q->prior; temp->next=q; temp->data.address=q->data.address; temp->data.num=q->data.num; q->prior->next=temp; q->prior=temp; q->data.address+=request; q->data.length=ch; q->data.num+=1; return OK; } return OK; } //分配主存 Status allocation(int a) { int request;//申请内存大小 printf("请输入申请分配的主存大小(单位:KB):"); scanf("%d",&request); if(request<0 ||request==0) { printf("分配大小不合适，请重试！"); return ERROR; } switch(a) { case 1://默认首次适应算法 if(First_fit(request)==OK) printf("\t****分配成功！****"); else printf("\t****内存不足，分配失败！****"); return OK; break; case 2://选择最佳适应算法 if(Best_fit(request)==OK) printf("\t****分配成功！****"); else printf("\t****内存不足，分配失败！****"); return OK; break; case 3://选择最差适应算法 if(Worst_fit(request)==OK) printf("\t****分配成功！****"); else printf("\t****内存不足，分配失败！****"); return OK; break; } } Status deal1(Node *p)//处理回收空间 { Node *q=first; for(;q!=NULL;q=q->next) { if(q==p) { if(q->prior->data.state==0&&q->next->data.state!=0) { q->prior->data.length+=q->data.length; q->prior->next=q->next; q->next->prior=q->prior; q=q->prior; q->data.state=0; q->data.num=flag-1; } if(q->prior->data.state!=0&&q->next->data.state==0) { q->data.length+=q->next->data.length; q->next=q->next->next; q->next->next->prior=q; q->data.state=0; q->data.num=flag; } if(q->prior->data.state==0&&q->next->data.state==0) { q->prior->data.length+=q->data.length; q->prior->next=q->next; q->next->prior=q->prior; q=q->prior; q->data.state=0; q->data.num=flag-1; }