C语言课程设计-存储管理分区分配算法|c语言程序代码编程小程序设计|c语言课程设计报告课程案例/***pcb.c***/#include "stdio.h"#include "stdlib.h"#include "string.h"#define MAX 32767typedef struct node /*设置分区描述器*/{ int address,size; struct node *next;}RECT;/*函数原型*/RECT *assignment(RECT *head,int application);void acceptment1(RECT *head,RECT *back1);void acceptment2(RECT *head,RECT *back1) ;int backcheck(RECT *head,RECT *back1);void print(RECT *head);/*变量声明*/RECT *head,*back,*assign1,*p;int application1,maxblocknum;char way;/*主函数*/main(){ char choose[10]; int check; head=malloc(sizeof(RECT)); /*建立可利用区表的初始状态*/ p=malloc(sizeof(RECT)); head->size=MAX; head->address=0; head->next=p; maxblocknum=1; p->size=MAX; p->address=0; p->next=NULL; print(head); /*输出可利用表初始状态*/ printf("Enter the way(best or first(b/f)\n");/*选择适应策略*/ scanf("%c",&way); do{ printf("Enter the assign or accept(as/ac)\n"); scanf("%s",choose); /*选择分配或回收*/ if(strcmp(choose,"as")==0) /*as为分配*/ { printf("Input application:\n"); scanf("%d",&application1);/*输入申请空间大小*/ assign1=assignment(head,application1);/*调用分配函数*/ if(assign1->address==-1)/*分配不成功*/ printf("Too large application!,assign fails!!\n\n"); else printf("Success!!ADDRESS=%5d\n",assign1->address); /*分配成功*/ print(head); /*输出*/ } else if(strcmp(choose,"ac")==0) /*回收*/ { back=malloc(sizeof(RECT)); printf("Input Adress and Size!!\n"); scanf("%d%d",&back->address,&back->size);/*输入回收地址和大小*/ check=backcheck(head,back); /*检查*/ if(check==1) { if(tolower(way)=='f')/*首先适应算法*/ acceptment1(head,back); /*首先适应*/ else acceptment2(head,back);/*最佳适应*/ print(head); } } }while(!strcmp(choose,"as")||!strcmp(choose,"ac"));}/*分配函数*/RECT *assignment(RECT *head,int application){ RECT *after,*before,*assign; assign=malloc(sizeof(RECT)); /*分配申请空间*/ assign->size=application; assign->next=NULL; if(application>head->size||application<=0) assign->address=-1; /*申请无效*/ else { before=head; after=head->next; while(after->size
next; after=after->next; } if(after->size==application) /*结点大小等于申请大小则完全分配*/ { if(after->size==head->size) maxblocknum--; before->next=after->next; assign->address=after->address; free(after); } else { if(after->size==head->size) maxblocknum--; after->size=after->size-application; /*大于申请空间则截取相应大小分配*/ assign->address=after->address+after->size; if(tolower(way)=='b')/*如果是最佳适应，将截取后剩余结点重新回收到合适位置*/ { before->next=after->next; back=after; acceptment2(head,back); } } if(maxblocknum==0) /*修改最大数和头结点值*/ { before=head; head->size=0; maxblocknum=1; while(before!=NULL) { if(before->size>head->size) { head->size=before->size; maxblocknum=1; } else if(before->size==head->size) maxblocknum++; before=before->next; } } } assign1=assign; return assign1; /*返回分配给用户的地址*/}void acceptment1(RECT *head,RECT *back1)/*首先适应*/{ RECT *before,*after; int insert; before=head; after=head->next; insert=0; while(!insert) /*将回收区插入空闲区表*/ { if((after==NULL)|| ((back1->address<=after->address)&& (back1->address>=before->address))) { before->next=back1; back1->next=after; insert=1; } else { before=before->next; after=after->next; } } if(back1->address==before->address+before->size)/*与上一块合并*/ { before->size=before->size+back1->size; before->next=back1->next; free(back1); back1=before; } if(after!=NULL&&(after->address==back1->address+back1->size)) { /*与下一块合并*/ back1->size=back1->size+after->size; back1->next=after->next; free(after); } if(head->sizesize) /*修改最大块值和最大块个数*/ { head->size=back1->size; maxblocknum=1; } else if(head->size==back1->size) maxblocknum++;}/*最佳适应，back1为回收结点的地址*/void acceptment2(RECT *head,RECT *back1){ RECT *before,*after; int insert ; insert=0; before=head; after=head->next; if(head->next==NULL) /*如果可利用区表为空*/ { head->size=back1->size; head->next=back1; maxblocknum++; back1->next=NULL; } else { while(after!=NULL) /*与上一块合并*/ if(back1->address==after->size+after->address) { before->next=after->next; back->size=after->size+back1->size; free(after); after=NULL;
} else { after=after->next; before=before->next; } before=head; after=head->next; while(after!=NULL) if(after->address==back1->size+back1->address) /*与下一块合并*/ { back1->size=back1->size+after->size; before->next=after->next; free(after); after=NULL; } else { before=before->next; after=after->next; } before=head;/*将回收结点插入到合适的位置*/ after=head->next; do{ if(after==NULL||(after->size>back1->size)) { before->next=back1; back1->next=after; insert=1; } else { before=before->next; after=after->next; } }while(!insert); if(head->sizesize) /*修改最大块值和最大块数*/ { head->size=back1->size; maxblocknum++; } else if(head->size==back1->size) maxblocknum++; }}void print(RECT *head) /*输出链表*/{ RECT *before,*after; int index,k; before=head->next; index=1; if(head->next==NULL) printf("NO part for assignment!!\n"); else { printf("*****index*******address********end*********size*****\n"); while(before!=NULL) { printf("----------------------------------------------------\n"); printf(" %-13d%-13d%-13d%-13d\n",index,before->address,before->address+before->size-1,before->size); printf("----------------------------------------------------\n"); index++; before=before->next; } }}/*检查回收块的合法性，back1为要回收的结点地址*/int backcheck(RECT *head,RECT *back1){ RECT *before,*after; int check=1; if(back1->address<0||back1->size<0) check=0;/*地址和大小不能为负*/ before=head->next; while((before!=NULL)&&check)/*地址不能和空闲区表中结点出现重叠*/ if(((back1->addressaddress) &&(back1->address+back1->size>before->address)) ||((back1->address>=before->address) &&(back1->addressaddress+before->size))) check=0; else before=before->next; if(check==0) printf("Error input!!\n"); return check; /*返回检查结果*/}
