操作系统存储器管理源代码 

动态分区分配模拟项目源代码

#include #include #define Free 0 #define Busy 1 #define OK 1 #define ERROR 0

#define MAX_length 1280 typedef int Status; typedef struct freearea { int ID;

long size; long address; int state; }ElemType;

typedef struct DuLNode //double linked list { ElemType data;

struct DuLNode *prior; struct DuLNode *next; }DuLNode,*DuLinkList; DuLinkList block_first; DuLinkList block_last; Status alloc(int); Status free(int);

Status First_fit(int,int); Status Best_fit(int,int); void show();

Status Initblock(); Status Initblock() {

block_first=(DuLinkList)malloc(sizeof(DuLNode)); block_last=(DuLinkList)malloc(sizeof(DuLNode)); block_first->prior=NULL; block_first->next=block_last; block_last->prior=block_first; block_last->next=NULL; block_last->data.address=0;

block_last->data.size=MAX_length; block_last->data.ID=0;

block_last->data.state=Free; return OK; }

Status alloc(int ch) {

int ID,request;

cout<<\请输入作业(分区号)：\ cin>>ID;

cout<<\请输入需要分配的主存大小(单位:KB)：\ cin>>request;

if(request<0 ||request==0) {

cout<<\分配大小不合适，请重试！\ return ERROR; }

if(ch==2) //选择最佳适应算法

{ if(Best_fit(ID,request)==OK) cout<<\分配成功！\ else cout<<\内存不足，分配失败！\ return OK; }

else //默认首次适应算法

{ if(First_fit(ID,request)==OK) cout<<\分配成功！\ else cout<<\内存不足，分配失败！\ return OK; } }

Status First_fit(int ID,int request) {

DuLinkList temp=(DuLinkList)malloc(sizeof(DuLNode)); temp->data.ID=ID; temp->data.size=request; temp->data.state=Busy;

DuLNode *p=block_first->next; while(p) {

if(p->data.state==Free && p->data.size==request) {

p->data.state=Busy; p->data.ID=ID; return OK; break; }

if(p->data.state==Free && p->data.size>request) { temp->prior=p->prior; temp->next=p;

temp->data.address=p->data.address; p->prior->next=temp; p->prior=temp;

p->data.address=temp->data.address+temp->data.size;

p->data.size-=request; return OK; break; }

p=p->next; }

return ERROR; }

Status Best_fit(int ID,int request) {

int ch;

DuLinkList temp=(DuLinkList)malloc(sizeof(DuLNode)); temp->data.ID=ID; temp->data.size=request; temp->data.state=Busy;

DuLNode *p=block_first->next; DuLNode *q=NULL; while(p) {

if(p->data.state==Free &&

(p->data.size>request || p->data.size==request) ) { q=p;

ch=p->data.size-request; break; }

p=p->next; }

while(p) {

if(p->data.state==Free && p->data.size==request) {

p->data.ID=ID; p->data.state=Busy; return OK; break; }

if(p->data.state==Free && p->data.size>request) {

if(p->data.size-request

ch=p->data.size-request; q=p; } }

p=p->next; }

if(q==NULL) return ERROR;//没有找到空闲块 else {

temp->prior=q->prior; temp->next=q;

temp->data.address=q->data.address; q->prior->next=temp; q->prior=temp;

q->data.address+=request; q->data.size=ch; return OK; } }

Status free(int ID) {

DuLNode *p=block_first; while(p)

{ if(p->data.ID==ID) {

p->data.state=Free; p->data.ID=Free;

if(p->prior->data.state==Free)

{ p->prior->data.size+=p->data.size; p->prior->next=p->next; p->next->prior=p->prior; }

if(p->next->data.state==Free) {

p->data.size+=p->next->data.size; p->next->next->prior=p;

p->next=p->next->next; }

break; }

p=p->next; }

return OK; }

void show()

{ cout<<\ cout<<\ 主 存 分 配 情 况 +++\\n\

cout<<\ DuLNode *p=block_first->next; while(p)

{ cout<<\分 区 号：\

if(p->data.ID==Free) cout<<\ else cout<data.ID<

cout<<\起始地址：\

cout<<\分区大小：\ cout<<\状 态：\

if(p->data.state==Free) cout<<\空 闲\ else cout<<\已分配\

cout<<\——————————————\ p=p->next; } }

//----------------------- 主 函 数--------------------------- void main() {

int ch;

cout<<\ 动态分区分配方式的模拟 \\n\ cout<<\ cout<<\首次适应算法 2)最佳适应算法 **\\n\ cout<<\ cout<<\请选择分配算法：\ cin>>ch; Initblock(); int choice; while(1) {

cout<<\ cout<<\ 1: 分配内存 2: 回收内存 **\\n\ cout<<\ 3: 查看分配 0: 退 出 **\\n\ cout<<\ cout<<\请输入您的操作 ：\ cin>>choice;

if(choice==1) alloc(ch); // 分配内存 else if(choice==2) // 内存回收 {

int ID;

cout<<\请输入您要释放的分区号：\ cin>>ID; free(ID); }

else if(choice==3) show();//显示主存