a.cpp

操作系统内存管理模拟实验源代码

#include"a.h"
void initiation()
{  freep=new freeptr;
   freep->size=total;
   freep->address=setaddress;
   freep->next=NULL;
   freep->back=NULL;
   totalfree=total;
   jobp=NULL;
   jobnumber=0;
}
//----------------------------------------
int  ffallocation(int jl,char *jn)
//int  jl;  //作业长度
//char    jn[10]; //作业名
{   
   int     ja;
   freeptr *fp;
   jobptr  *jp,*jp1,*jp2;
   ja=-1;
   if (totalfree<jl)
       { printf("can't allocation ");
	 return 0;
       }
   ja=0;
   fp=freep;
   while(fp!=NULL)
     if (fp->size<jl)
       fp=fp->next;
	 else
       {jobnumber++;
	    totalfree=totalfree-jl;
	    jp2=new jobptr;
	     strcpy(jp2->name,jn);
	    jp2->length=jl;
	     jp2->address=fp->address;
	     ja=jp2->address;
	         if (jobp==NULL)
			 { jp2->next=NULL;
	            jp2->back=NULL;
	             jobp=jp2;
			 }
	         else
				{ jp=jobp;
				while ((jp != NULL) && (jp2->address<jp->address))
					{ jp1=jp;
		              jp=jp->next;
					}
	            jp2->next=jp;
	             if (jp==NULL)
					{ jp2->back=jp1;
						jp1->next=jp2;
					}
				else
					{ jp2->back=jp->back;
					if (jp->back!=NULL)
						jp1->next=jp2;
		            else jobp=jp2;
						jp->back=jp2;
					}
				}
		if (fp->size-jl<min)
		{ if (fp->next!=NULL)
			fp->next->back=fp->back;
			 if (fp->back!=NULL)
			fp->back->next=fp->next;
			else freep=fp->next;
		}
else
	{  fp->size=fp->size-jl;
	fp->address=fp->address+jl;
	  }
return (ja);
  }
}

	//--------------------------------------------
void showyou()
{jobptr *jp;

   if (jobnumber<0)
      printf("no job\n");
    else
      { printf("       name      length      address\n");
	jp=jobp;
	while (jp!=NULL)
	  { printf("%11s%11d%13d\n",jp->name,jp->length,jp->address);
	    jp=jp->next;
	  }
      }
    printf("the total left is %d byte\n",totalfree);
}
//--------------------------------------------------
void ffcollection(char *jn)

{
freeptr *fp,*fp1,*fp2;
   jobptr  *jp;
   int     f;

   jp=jobp;
   f=0;
   while ( (jp!=NULL) && strcmp(jp->name,jn) )
     jp=jp->next;
   if (jp!=NULL)
     { jobnumber--;
       totalfree=totalfree+jp->length;
       if (freep==NULL)
	 { freep=(freeptr *)malloc(sizeof(freeptr));
	   freep->address=jp->address;
	   freep->size=jp->length;
	   freep->next=NULL;
	   freep->back=NULL;
	 }
	   else
	 { fp=freep;
	   while ( (fp!=NULL) && (fp->address<jp->address) )
	     {  fp1=fp;
		fp=fp->next;
	     }
	   if (fp!=NULL)
	     {  if ((fp->next!=NULL) && (fp->next->address==jp->address+jp->length))
		   f=f+1;
		if ((fp->back!=NULL) && (jp->address==fp->address+fp->size))
		   f=f+2;
	     }
	   else
	     if ( jp->address==fp1->address+fp1->size )
		f=f+2;
switch(f)
	   { case 0:{ fp2=(freeptr *)malloc(sizeof(freeptr));
		      fp2->address=jp->address;
		      fp2->size=jp->length;
		      fp2->next=fp;
		      if (fp!=NULL)
			{ fp2->back=fp->back;
			  if (fp->back!=NULL)
			     fp1->next=fp2;
			  else
			     freep=fp2;
			  fp->back =fp2;
			}
		      else
			{ fp2->back=fp1;
			  fp1->next=fp2;
			}
		     break;
		     }
case 1:{fp->size=fp->size+jp->length;
	fp->address=jp->address;       break;
	}
case 2: { fp1->size=fp->size+jp->length;	break;
	}
case 3:{ fp->size=fp1->size+jp->length+fp->size;
	 fp1->next=fp->next;
	 if(fp->next!=NULL)
		 { fp->next->back=fp2;     free(fp);
		 }
	break;
 }
}
   }
 if (jp==jobp) jobp=jp->next;
 if (jp->next!=NULL) jp->next->back=jp->back;
 if (jp->back!=NULL) jp->back->next=jp->next;
  free(jp);
     }
    if (!(strcmp(jp->name,jn)))
       printf("cant't find %s,so can't collect %s",jn,jn);
}

//---------------------------------------------------
void coalesce()
{ freeptr *fp,*fp1;
  jobptr  *jp;  int bottom;
  if (jobnumber>0)
    { jp=jobp;
      bottom=total+setaddress;
      while (jp!=NULL)
	{ jp->address=bottom-jp->length;
	  bottom=bottom-jp->length;
	  jp=jp->next;
	}
      fp=freep;
      while (fp!=NULL)
	{ fp1=fp;	  fp=fp->next;	  free(fp1);
	}
      freep=(freeptr *)malloc(sizeof(freeptr));
      freep->size=totalfree;
      freep->address=setaddress;
      freep->next=NULL;
      freep->back=NULL;
   }
}
//-------------------------------------------------------------------------
void menu()
{ char name[10]; int  length,address;  int     select=0;
  while (select!=4)
  {   system("cls");
  printf("\n");
  printf("       ************ memory management program **********\n");
  printf("\n");
  printf("\n");
  printf("        you can select one of the following:\n" );
  printf("____________________________________________________\n");
  printf("     (1) require to be allocate.\n");
  printf("     (2) require to collecte the size.\n");
  printf("     (3) check the memory.\n");
  printf("     (4) quit.\n");  printf("____________________________________________________\n");
  printf("\n");
  printf("\n");
  printf(" which would you select ? please inpute 1,2,3,4.\n");
  scanf("%d",&select);
  while ( (select!=1) && (select!=2) && (select!=3) && (select!=4) )
     scanf("%d",&select);
  switch(select)
  { case 1: { if ( jobnumber>max )	 printf("the job is too many.\n");
	      else
		 { printf("enter you job name:\n");   scanf("%s",name);
		   printf("enter you job length:\n");   scanf("%d",&length);
		   address=ffallocation(length,name);
            switch(address)
		   { case -1:   printf("the momory is full.\n");	break;
		     case  0: { coalesce();
				ffallocation(length,name);
				showyou();break;
			      }
		     default: showyou();break;
		   }
		 }
          char c;
		  scanf("%c",&c);
		  break;
	      }
case 2: { printf("\nenter the name of the job want to collect the size:\n");
	       scanf("%s",name);
	       ffcollection(name);
	       showyou();
	      char c;
		  scanf("%c",&c);
		break;
	     }
     case 3: { showyou();
	     char c;
		  scanf("%c",&c);
		break;
	     }
     case 4: exit(1);break;

   }
  }
}
void main()
{
  initiation();
  menu();
   char c;
		  scanf("%c",&c);
		
}

  //----------------------------------------------------