實驗名稱:動態(tài)分區(qū)分配方式模擬
實驗?zāi)康?/h4>
進(jìn)一步加深對動態(tài)分區(qū)分配管理方式的理解;掌握動態(tài)分區(qū)分配方式使用的數(shù)據(jù)結(jié)構(gòu)、分配算法和回收算法
實驗內(nèi)容
編寫C語言程序,模擬實現(xiàn)首次/最佳/最壞適應(yīng)算法的內(nèi)存塊分配和回收,要求每次分配和回收后顯示出空閑分區(qū)和已分配分區(qū)的情況。假設(shè)初始狀態(tài)下,可用的內(nèi)存空間為640K。
數(shù)據(jù)結(jié)構(gòu)設(shè)計
- 空閑分區(qū)表:Unallocated Table
index | address | end | size |
---|---|---|---|
0 | 0 | 639 | 640 |
- 已分配分區(qū)表:Allocated Table
index | address | end | size |
---|---|---|---|
0 | 630 | 639 | 10 |
分配算法設(shè)計
- 首次適應(yīng)算法
- 最佳適應(yīng)算法
- 最差適應(yīng)算法
根據(jù)選擇的分配算法決定空閑分區(qū)表的排序方式
回收算法設(shè)計
文章來源:http://www.zghlxwxcb.cn/news/detail-768257.html
- 上下都無空分區(qū)
- 有上空分區(qū)無下空分區(qū)
- 無上空分區(qū)有下空分區(qū)
- 上下分區(qū)都為空分區(qū)
代碼:文章來源地址http://www.zghlxwxcb.cn/news/detail-768257.html
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<ctype.h>
#define MAX 640
struct node //定義分區(qū)
{
int address, size;
struct node *next;
};
typedef struct node RECT;
/*-----函數(shù)定義-------*/
void firstfit(RECT *head,int application); //針對首次適應(yīng)分配算法分配分區(qū)
void bestfit(RECT *head,int application); //針對最佳適應(yīng)分配算法分配分區(qū)
void worstfit(RECT *head,int application); //針對最壞適應(yīng)分配算法分配分區(qū)
int backcheck(RECT *head,RECT *back1); //合法性檢查
void recycle(RECT *head,RECT *heada,RECT *back1); //回收分區(qū)
void print(RECT *head); //輸出已分配分區(qū)表或空閑分區(qū)
/*-----變量定義-------*/
RECT *head,*heada,*back,*assign1,*p;
int application1,maxblocknum;
char way; //用于定義分配方式:首先適應(yīng)(f)、最佳適應(yīng)(b)、最差適應(yīng)(w)
int main()
{
char choose;
int check;
RECT *allocated; //
head=malloc(sizeof(RECT)); //建立空閑分區(qū)表的初始狀態(tài)
p=malloc(sizeof(RECT));
head->size=MAX;
head->address=0;
head->next=p;
maxblocknum=1; //初始只有一塊空閑區(qū)
p->size=MAX;
p->address=0;
p->next=NULL;
print(head); //輸出空閑分區(qū)表的初始狀態(tài)
printf("Enter the way (first, best or worst (f/b/w))\n");
scanf("%c",&way);
heada=malloc(sizeof(RECT)); //建立已分配分區(qū)表的初始狀態(tài)
heada->size=0;
heada->address=0;
heada->next=NULL;
//print(heada); //輸出空閑分區(qū)表的初始狀態(tài)
//way='f';
do
{
printf("Enter the allocate or reclaim (a/r),or press other key to exit.\n");
scanf(" %c",&choose); //選擇分配或回收
if(tolower(choose)=='a') //a為分配
{
printf("Input application:\n");
scanf("%d",&application1); //輸入申請空間大小
if(tolower(way)=='f')
firstfit(head,application1); //首先適應(yīng)算法分配
else if(tolower(way)=='b')
bestfit(head,application1); //調(diào)用最佳適應(yīng)分配算法函數(shù)分配內(nèi)存
else
worstfit(head,application1); //最壞適應(yīng)算法分配
if (assign1->address==-1) //分配不成功
printf("Too large application! Allocation fails! \n\n");
else{//分配成功
printf("Allocation Success! ADDRESS=%5d\n",assign1->address);
printf("\n*********Unallocated Table**********\n");
print(head); //輸出
printf("\n*********Allocated Table************\n");
print(heada);
}
}
else if (tolower(choose)=='r') //回收內(nèi)存
{
back=malloc(sizeof(RECT));
printf("Input address and Size:\n");
scanf("%d%d",&back->address,&back->size);//輸入回收地址和大小
check=backcheck(head,back);
if (check==1)
{
recycle(head,heada,back);
printf("\n*********Unallocated Table**********\n");
print(head); //輸出
printf("\n*********Allocated Table************\n");
print(heada);
}
}
}while(tolower(choose)=='a'||tolower(choose)=='r');
exit(0);
} //main() end.
/*-------內(nèi)存回收函數(shù),back1為回收節(jié)點到地址-------*/
void recycle(RECT *head,RECT *heada,RECT *back1)
{
RECT *before, *after, *back2;
int insert = 0, del;
back2 = malloc(sizeof(RECT));
back2->address = back1->address;
back2->size = back1->size;
back2->next = back1->next;
before = head;
after = head->next;
if (head->next == NULL) // 沒有空閑區(qū),直接回收
{
head->size = back1->size;
head->next = back1;
maxblocknum++;
back1->next = NULL;
}
else
{
while (!insert&&after!=NULL) // 遍歷空閑區(qū)
{
if (back1->address == after->size + after->address) /*要回收的內(nèi)存在當(dāng)前空閑區(qū)之后,與上一塊合并*/
{//第一種情況,回收區(qū)與相鄰低地址合并
after->size+=back1->size;
insert=1;
// before->next = after->next;
// back->size = after->size + back1->size;
// free(after);
// after = NULL;
}else if(back1->address+back1->size==after->address)
{ //第二種情況,回收區(qū)與相鄰高地址合并
after->size+=back1->size;
after->address=back1->address;
insert=1;
}else if(before->address<back1->address&&after->address>back1->address)
{ //第三種情況,回收區(qū)與相鄰的高地址、低地址合并,被夾在中間
before->size+=back1->size+after->size;
insert=1;
}
after = after->next;
before = before->next;
}
//第四種情況,回收區(qū)獨自一塊,需要在空閑表中新增一項
before = head; /*將回收節(jié)點插入到合適到位置*/
after = head->next;
do
{
if (after == NULL)
{
before->next = back1;
back1->next = after;
insert = 1;
}
else
{
before = before->next;
after = after->next;
}
} while (!insert);
if (head->size < back1->size) /*修改最大塊值和最大塊數(shù)*/
{
head->size = back1->size;
maxblocknum++;
}
else
{
if (head->size == back1->size)
maxblocknum++;
}
}
// 修改已分配分區(qū)表,刪除相應(yīng)節(jié)點
before = heada;
after = heada->next;
del = 0;
while (!del &&after != NULL) // 1,循環(huán)在已刪除或者遍歷結(jié)束時退出,將回收區(qū)從已分配分區(qū)表中刪除
{
if ((after->address == back2->address) && (after->size == back2->size))
{
before->next = after->next;
free(after);
del = 1;
}
else
{
before = before->next;
after = after->next;
}
}
heada->size--;
}
/*------------------首次適應(yīng)分配算法------------*/
void firstfit(RECT *head,int application)
{
RECT *after, *before, *assign;
assign = malloc(sizeof(RECT)); // 申請分配空間
assign->size = application;
assign->next = NULL;
if (application > head->size || application < 0)
assign->address = -1; // 申請無效
else
{
before = head;
after = head->next;
while (after->size < application) // 遍歷鏈表,查找合適到節(jié)點
{
before = before->next;
after = after->next;
}
if (after->size == application) // 若節(jié)點大小等于申請大小則完全分配
{
if (after->size == head->size)
maxblocknum--;
before->next = after->next; // 指向后面的空閑區(qū)
assign->address = after->address; // 將這個同樣大小的地址直接賦給分配的對象
free(after);
}
else
{
if (after->size == head->size) // 這個可分配空間等于剩余總的空閑空間
maxblocknum--;
after->size = after->size - application; // 大于申請空間則截取相應(yīng)大小分配
assign->address = after->address + after->size; // 分配靠后的地址
}
if (maxblocknum == 0) // 修改最大數(shù)和頭節(jié)點
{
before = head;
head->size = 0;
maxblocknum = 1;
while (before != NULL) // 遍歷空閑區(qū)
{
if (before->size > head->size)
{
head->size = before->size;
maxblocknum = 1;
}
else if (before->size == head->size)
maxblocknum++;
before = before->next;
}
}
}
assign1 = assign;
// 修改已分配分區(qū)表,添加節(jié)點
after = heada;
while (after->next != NULL)
after = after->next;
after->next = assign;
heada->size++;
}
/*-----------------最佳適應(yīng)分配算法--------------*/
void bestfit(RECT *head,int application)
{
RECT *after, *before, *assign;
assign = malloc(sizeof(RECT)); // 申請分配空間
assign->size = application;
assign->next = NULL;
if (application > head->size || application < 0)
assign->address = -1; // 申請無效
else
{
before = head;
RECT* ptr = head->next;
int tmp=0;
//找到第一塊最合適的空閑分區(qū),即空間大于application的最小分區(qū)
while (ptr!=NULL) // 遍歷鏈表,查找合適到節(jié)點
{
if(ptr->size>=application){
if(!tmp||ptr->size<tmp){
after=ptr;
tmp=ptr->size;
}
}
ptr=ptr->next;
}
if (after->size == application) // 若節(jié)點大小等于申請大小則完全分配
{
if (after->size == head->size)
maxblocknum--;
before->next = after->next; // 指向后面的空閑區(qū)
assign->address = after->address; // 將這個同樣大小的地址直接賦給分配的對象
free(after);
}
else
{
if (after->size == head->size) // 這個可分配空間等于剩余總的空閑空間
maxblocknum--;
after->size = after->size - application; // 大于申請空間則截取相應(yīng)大小分配
assign->address = after->address + after->size; // 分配靠后的地址
}
if (maxblocknum == 0) // 修改最大數(shù)和頭節(jié)點
{
before = head;
head->size = 0;
maxblocknum = 1;
while (before != NULL) // 遍歷空閑區(qū)
{
if (before->size > head->size)
{
head->size = before->size;
maxblocknum = 1;
}
else if (before->size == head->size)
maxblocknum++;
before = before->next;
}
}
}
assign1 = assign;
// 修改已分配分區(qū)表,添加節(jié)點
after = heada;
while (after->next != NULL)
after = after->next;
after->next = assign;
heada->size++;
}
/*-----------------最壞適應(yīng)分配算法--------------*/
void worstfit(RECT *head,int application)
{
RECT *after, *before, *assign;
assign = malloc(sizeof(RECT)); // 申請分配空間
assign->size = application;
assign->next = NULL;
if (application > head->size || application < 0)
assign->address = -1; // 申請無效
else
{
before = head;
RECT* ptr = head->next;
int tmp=0;
//找到最大的空閑分區(qū)進(jìn)行分配
while (ptr!=NULL) // 遍歷鏈表,查找合適到節(jié)點
{
if(ptr->size>=application){
if(ptr->size>tmp){
after=ptr;
tmp=ptr->size;
}
}
ptr=ptr->next;
}
if (after->size == application) // 若節(jié)點大小等于申請大小則完全分配
{
if (after->size == head->size)
maxblocknum--;
before->next = after->next; // 指向后面的空閑區(qū)
assign->address = after->address; // 將這個同樣大小的地址直接賦給分配的對象
free(after);
}
else
{
if (after->size == head->size) // 這個可分配空間等于剩余總的空閑空間
maxblocknum--;
after->size = after->size - application; // 大于申請空間則截取相應(yīng)大小分配
assign->address = after->address + after->size; // 分配靠后的地址
}
if (maxblocknum == 0) // 修改最大數(shù)和頭節(jié)點
{
before = head;
head->size = 0;
maxblocknum = 1;
while (before != NULL) // 遍歷空閑區(qū)
{
if (before->size > head->size)
{
head->size = before->size;
maxblocknum = 1;
}
else if (before->size == head->size)
maxblocknum++;
before = before->next;
}
}
}
assign1 = assign;
// 修改已分配分區(qū)表,添加節(jié)點
after = heada;
while (after->next != NULL)
after = after->next;
after->next = assign;
heada->size++;
}
/*-----------------打印輸出鏈表--------------*/
void print(RECT *output)
{
RECT *before;
int index;
before=output->next;
index=0;
if(output->next==NULL)
printf("NO part for print!\n");
else
{
printf("index****address****end*****size**** \n");
while(before!=NULL)
{
printf("------------------------------------\n");
printf(" %-9d%- 9d%- 9d%- 9d\n",index,before->address,before->address+before->size-1,before->size);
printf("------------------------------------\n");
index++;
before=before->next;
}
}
}
/*檢查回收塊到合法性,back1為要回收到節(jié)點地址*/
int backcheck(RECT *head,RECT *back1)
{
RECT *before;
int check=1;
if(back1->address<0 || back1->size<0) check=0; //地址和大小不能為負(fù)數(shù)
before=head->next;
while((before!=NULL)&&check) //地址不能和空閑區(qū)表中節(jié)點出現(xiàn)重疊
if(((back1->address<before->address)&&(back1->address+back1->size>before->address))||((back1->address>=before->address)&&(back1->address<before->address+before->size)))
check=0;
else
before=before->next;
if(check==0) printf("Error input!\n");
return check;
}
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