操作系统存储器管理源代码
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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; } }