实验四 动态分区分配算法Word格式.docx
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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
2'
set_algorithm();
flag=1;
//设置算法
3'
new_process();
flag=1;
//创建新进程
4'
kill_process();
//删除进程
5'
display_mem_usage();
//显示内存使用
0'
do_exit();
exit(0);
//释放链表并退出
default:
}
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;
start_addr=DEFAULT_MEM_START;
fb->
next=NULL;
returnfb;
voiddisplay_menu(){
printf(\
);
printf(-Setmemorysize(default=%d)\n,DEFAULT_MEM_SIZE);
printf(-Selectmemoryallocationalgorithm\n);
printf(-Newprocess\n);
printf(-Terminateaprocess\n);
printf(_x0005_-Displaymemoryusage\n);
printf(
intset_mem_size(){
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->
voidset_algorithm(){
intalgorithm;
printf(\1-FirstFit\n);
printf(\2-BestFit\n);
printf(\3-WorstFit\n);
algorithm);
if(algorithm>
=1&
&
algorithm<
=3){
ma_algorithm=algorithm;
else
牰湩晴尨输入有误,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();
caseMA_BF:
rearrange_BF();
caseMA_WF:
rearrange_WF();
//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){
min_addr=temp->
p=temp;
temp=temp->
next;
if(NULL!
=p){
temp=p->
p->
next=p->
temp->
next=free_block;
free_block=temp;
thead=free_block;
p=free_block;
temp=free_block->
while(thead->
min_addr=thead->
if(p->
=thead->
next){
next=thead->
thead->
next=temp;
thead=thead->
p=thead;
temp=thead->
//最佳适应算法
intrearrange_BF(){
//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
//当前的最小内存
intmin_size=free_block->
size;
size<
min_size){
min_size=temp->
min_size=thead->
//最坏适应算法
intrearrange_WF(){
//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
//当前的最大内存
intmax_size=free_block->
size>
max_size){
max_size=temp->
max_size=thead->
return1;
intnew_process(){
structallocated_block*ab;
intret;
ab=(structallocated_block*)malloc(sizeof(structallocated_block));
if(!
ab)exit(-5);
ab->
pid++;
sprintf(ab->
process_name,PROCESS-d,pid);
pid=pid;
printf(Memoryfor%s:
ab->
process_name);
size=size;
汥敳瀠楲瑮?
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;
elseif(ret==1){
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->
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->
request_size)
else{
while(NULL!
=fbt&
fbt->
request_size){
pre=fbt;
fbt=fbt->
=free_block->
sum=free_block->
=temp){
sum+=temp->
if(sum>
=request_size)
if(NULL==temp)
pre=free_block;
max=free_block->
=pre){
if(max<
pre->
start_addr){
max=pre->
fbt=pre;
pre=pre->
tp=allocated_block_head;
tt=free_block;
if(pre!
=fbt){
=tp){
if(tp->
start_addr>
start_addr)
tp->
start_addr=tp->
start_addr-pre->
tp=tp->
=tt){
if(tt->
tt->
start_addr=tt->
tt=tt->
while(pre!
=temp->
=fbt)
free(pre);
free_block=fbt;
size=sum;
next=temp->
if(free_block->
size-request_size<
MIN_SLICE){
size=free_block->
start_addr=free_block->
free_block=free_block->
start_addr=fbt->
start_addr+request_size;
size-request_size;
//将内存块全部分配
if(fbt->
size=fbt->
if(pre->
next==free_block){
free_block=fbt->
next=fbt->
free(fbt);
fbt->
free(head);
voidkill_process(){
printf(KillProcess,pid=);
pid);
ab=find_process(pid);
if(ab!
=N