实验四动态分区分配算法.docx
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- 上传时间:2023-01-24
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实验四动态分区分配算法.docx
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实验四动态分区分配算法
实验内容:
存储器管理实验
一、 实验目的
采用首次适应算法(FF),最佳适应算法(BF),最坏适应算法(WF)三种不同的算法,实现对系统空闲区的动态分区分配。
二、实验题目
给予顺序搜索的动态分区算法的程序。
三、实验要求
读懂给出的核心代码,进行适当的修改,编译通过后,完成实验报告。
四、核心代码
#include
#include
#include
//常量定义
#definePROCESS_NAME_LEN32
#defineMIN_SLICE10
#defineDEFAULT_MEM_SIZE1024
#defineDEFAULT_MEM_START0
#defineMA_FF1
#defineMA_BF2
#defineMA_WF3
intmem_size=DEFAULT_MEM_SIZE;
intma_algorithm=MA_FF;
staticintpid=0;
intflag=0;
structfree_block_type{
intsize;
intstart_addr;
structfree_block_type*next;
};
structfree_block_type*free_block;
//描述已分配的内存块
structallocated_block{
intpid;intsize;
intstart_addr;
charprocess_name[PROCESS_NAME_LEN];
structallocated_block*next;
};
structallocated_block*allocated_block_head=NULL;
//函数声明
structfree_block_type*init_free_block(intmem_size);
voiddisplay_menu();
intset_mem_size();
voidset_algorithm();
voidrearrange(intalgorithm);
intrearrange_FF();
intrearrange_BF();
intrearrange_WF();
intnew_process();
intallocate_mem(structallocated_block*ab);
voidkill_process();
intfree_mem(structallocated_block*ab);
intdispose(structallocated_block*free_ab);
intdisplay_mem_usage();
voiddo_exit();
structallocated_block*find_process(intpid);
intmain(){
charchoice;pid=0;
free_block=init_free_block(mem_size);//初始化空闲区
while
(1){
display_menu();//显示菜单
fflush(stdin);
choice=getchar();//获取用户输入
switch(choice){
case'1':
set_mem_size();break;//设置内存大小
case'2':
set_algorithm();flag=1;break;//设置算法
case'3':
new_process();flag=1;break;//创建新进程
case'4':
kill_process();flag=1;break;//删除进程
case'5':
display_mem_usage();flag=1;break;//显示内存使用
case'0':
do_exit();exit(0);//释放链表并退出
default:
break;
}
}
return1;
}
structfree_block_type*init_free_block(intmem_size){
structfree_block_type*fb;
fb=(structfree_block_type*)malloc(sizeof(structfree_block_type));
if(fb==NULL){
printf("Nomem\n");
returnNULL;
}
fb->size=mem_size;
fb->start_addr=DEFAULT_MEM_START;
fb->next=NULL;
returnfb;
}
voiddisplay_menu(){
printf("\n");
printf("1-Setmemorysize(default=%d)\n",DEFAULT_MEM_SIZE);
printf("2-Selectmemoryallocationalgorithm\n");
printf("3-Newprocess\n");
printf("4-Terminateaprocess\n");
printf("5-Displaymemoryusage\n");
printf("0-Exit\n");
}
intset_mem_size(){
intsize;
if(flag!
=0){//防止重复设置
printf("Cannotsetmemorysizeagain\n");
return0;
}
printf("Totalmemorysize=");
scanf("%d",&size);
if(size>0){
mem_size=size;
free_block->size=mem_size;
}
flag=1;
return1;
}
voidset_algorithm(){
intalgorithm;
while
(1){
printf("\t1-FirstFit\n");
printf("\t2-BestFit\n");
printf("\t3-WorstFit\n");
scanf("%d",&algorithm);
if(algorithm>=1&&algorithm<=3){
ma_algorithm=algorithm;
break;
}
else
printf("输入有误,请重新输入!
\n");
}
//按指定算法重新排列空闲区链表
rearrange(ma_algorithm);
}
voidrearrange(intalgorithm){
switch(algorithm){
caseMA_FF:
rearrange_FF();break;
caseMA_BF:
rearrange_BF();break;
caseMA_WF:
rearrange_WF();break;
}
}
//首次适应算法
intrearrange_FF(){
structfree_block_type*temp;
//使用头插法,thead为临时头,p为最小地址的数据块的前一个结点
structfree_block_type*thead=NULL,*p=NULL;
//当前的最小地址
intmin_addr=free_block->start_addr;
temp=free_block;
while(temp->next!
=NULL){
if(temp->next->start_addr min_addr=temp->next->start_addr; p=temp; } temp=temp->next; } if(NULL! =p){ temp=p->next; p->next=p->next->next; temp->next=free_block; free_block=temp; } thead=free_block; p=free_block; temp=free_block->next; while(thead->next! =NULL){ min_addr=thead->next->start_addr; while(temp->next! =NULL){ if(temp->next->start_addr min_addr=temp->next->start_addr; p=temp; } temp=temp->next; } if(p->next! =thead->next){ temp=p->next; p->next=p->next->next; temp->next=thead->next; thead->next=temp; } thead=thead->next; p=thead; temp=thead->next; } return1; } //最佳适应算法 intrearrange_BF(){ structfree_block_type*temp; //使用头插法,thead为临时头,p为最小内存的数据块的前一个结点 structfree_block_type*thead=NULL,*p=NULL; //当前的最小内存 intmin_size=free_block->size; temp=free_block; while(temp->next! =NULL){ if(temp->next->size min_size=temp->next->size; p=temp; } temp=temp->next; } if(NULL! =p){ temp=p->next; p->next=p->next->next; temp->next=free_block; free_block=temp; } thead=free_block; p=free_block; temp=free_block->next; while(thead->next! =NULL){ min_size=thead->next->size; while(temp->next! =NULL){ if(temp->next->size min_size=temp->next->size; p=temp; } temp=temp->next; } if(p->next! =thead->next){ temp=p->next; p->next=p->next->next; temp->next=thead->next; thead->next=temp; } thead=thead->next; p=thead; temp=thead->next; } return1; } //最坏适应算法 intrearrange_WF(){ structfree_block_type*temp; //使用头插法,thead为临时头,p为最大内存的数据块的前一个结点 structfree_block_type*thead=NULL,*p=NULL; //当前的最大内存 intmax_size=free_block->size; temp=free_block; while(temp->next! =NULL){ if(temp->next->size>max_size){ max_size=temp->next->size; p=temp; } temp=temp->next; } if(NULL! =p){ temp=p->next; p->next=p->next->next; temp->next=free_block; free_block=temp; } thead=free_block; p=free_block; temp=free_block->next; while(thead->next! =NULL){ max_size=thead->next->size; while(temp->next! =NULL){ if(temp->next->size>max_size){ max_size=temp->next->size; p=temp; } temp=temp->next; } if(p->next! =thead->next){ temp=p->next; p->next=p->next->next; temp->next=thead->next; thead->next=temp; } thead=thead->next; p=thead; temp=thead->next; } return1; } intnew_process(){ structallocated_block*ab; intsize; intret; ab=(structallocated_block*)malloc(sizeof(structallocated_block)); if(! ab)exit(-5); ab->next=NULL; pid++; sprintf(ab->process_name,"PROCESS-d",pid); ab->pid=pid; while (1){ printf("Memoryfor%s: ",ab->process_name); scanf("%d",&size); if(size>0){ ab->size=size; break; } elseprintf("输入大小有误,请重新输入\n"); } ret=allocate_mem(ab); if((ret==1)&&(allocated_block_head==NULL)){ allocated_block_head=ab; return1; } elseif(ret==1){ ab->next=allocated_block_head; allocated_block_head=ab; return2;} elseif(ret==-1){ printf("Allocationfail\n"); pid--; free(ab); return-1; } return3; } intallocate_mem(structallocated_block*ab){ structfree_block_type*fbt,*pre,*head,*temp,*tt; structallocated_block*tp; intrequest_size=ab->size; intsum=0; intmax; head=(structfree_block_type*)malloc(sizeof(structfree_block_type)); pre=head; fbt=free_block; pre->next=fbt; if(ma_algorithm==MA_WF){ if(NULL==fbt||fbt->size return-1; } else{ while(NULL! =fbt&&fbt->size pre=fbt; fbt=fbt->next; } } if(NULL==fbt||fbt->size if(NULL! =free_block->next){ sum=free_block->size; temp=free_block->next; while(NULL! =temp){ sum+=temp->size; if(sum>=request_size) break; temp=temp->next; } if(NULL==temp) return-1; else{ pre=free_block; max=free_block->start_addr; fbt=free_block; while(temp->next! =pre){ if(max max=pre->start_addr; fbt=pre; } pre=pre->next; } pre=free_block; while(temp->next! =pre){ tp=allocated_block_head; tt=free_block; if(pre! =fbt){ while(NULL! =tp){ if(tp->start_addr>pre->start_addr) tp->start_addr=tp->start_addr-pre->size; tp=tp->next; } while(NULL! =tt){ if(tt->start_addr>pre->start_addr) tt->start_addr=tt->start_addr-pre->size; tt=tt->next; } } pre=pre->next; } pre=free_block; while(pre! =temp->next){ if(pre! =fbt) free(pre); pre=pre->next; } free_block=fbt; free_block->size=sum; free_block->next=temp->next; if(free_block->size-request_size ab->size=free_block->size; ab->start_addr=free_block->start_addr; pre=free_block; free_block=free_block->next; free(pre); } else{ ab->start_addr=fbt->start_addr; free_block->start_addr=free_block->start_addr+request_size; free_block->size=free_block->size-request_size; } } } else return-1; } else{ //将内存块全部分配 if(fbt->size-request_size ab->size=fbt->size; ab->start_addr=fbt->start_addr; if(pre->next==free_block){ free_block=fbt->next; } else pre->next=fbt->next; free(fbt); } else{ ab->start_addr=fbt->start_addr; fbt->start_addr=fbt->start_addr+request_size; fbt->size=fbt->size-request_size; } } free(head); rearrange(ma_algorithm); return1; } voidkill_process(){ structallocated_block*ab; intpid; printf("KillProcess,pid="); scanf("%d",&pid); ab=find_process(pid); if(ab! =NULL){ free_mem(ab); dispose(ab); } else{ printf("没有pid为%d的进程! \n",pid); } } structallocated_block*find_process(intpid){ structall
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- 关 键 词:
- 实验 动态 分区 分配 算法