mm_5.c

ICS 课程的Lab7

        else if(pre!=NULL && next==NULL)
        {
            PUT(NEXT(pre),(int)NULL);
            
            PUT(header,(int)bp);
            PUT(NEXT(bp),(int)header);
            PUT(bp,(int)NULL);
            
            header=bp;
           
            
        }
        else if (pre==NULL && next!=NULL)
            {
                PUT(next,(int)bp);
                
                PUT(bp,(int)NULL);
                PUT(NEXT(bp),(int)next);
                header=bp;
               
                
            }
        else
        {
            PUT(NEXT(pre),(int)next);
            PUT(next,(int)pre);
            
            PUT(header,(int)bp);
            PUT(NEXT(bp),(int)header);
            PUT(bp,(int)NULL);

            header=bp;
            
        }
        //return header;
        
    }else
    {
       void  *current1=PREV_BLKP(bp);
       void  *pre1 = (void *)(GET(current1));
       void  *next1=(void *)(GET(NEXT(current1)));
       void  *current2=NEXT_BLKP(bp);
       void  *pre2 = (void *)(GET(current2));
       void  *next2=(void *)(GET(NEXT(current2)));

       PUT(current1,(int)NULL);
       PUT(NEXT(current1),(int)NULL);
       
       PUT(current2,(int)NULL);
       PUT(NEXT(current2),(int)NULL);
        
        size += GET_SIZE(HDRP(PREV_BLKP(bp))) + GET_SIZE(FTRP(NEXT_BLKP(bp)));

        PUT(HDRP(PREV_BLKP(bp)),PACK(size,0));

        PUT(FTRP(NEXT_BLKP(bp)),PACK(size,0));

        bp=PREV_BLKP(bp);

        if(pre1==current2)
        {
            
            if(pre2==NULL && next1==NULL)
            {
                PUT(bp,(int)NULL);
                PUT(NEXT(bp),(int)NULL);
                
                header=bp;
                
            }
            else if(pre2!=NULL && next1==NULL)
            {
                PUT(NEXT(pre2),(int)NULL);
                
                PUT(bp,(int)NULL);
                PUT(header, (int)bp);                
                PUT(NEXT(bp),(int)header);
                header=bp;
                
            }
            else if(pre2==NULL && next1!=NULL)
            {
                PUT(NEXT(bp),(int)next1);
                
                PUT(next1,(int)bp);
                PUT(bp,(int)NULL);
                
                header=bp;
                
                
            }
            else 
            {
                PUT(NEXT(pre2),(int)next1);
                PUT(next1,(int)pre2);
                
                PUT(header,(int)bp);
                PUT(NEXT(bp),(int)header);
                
                PUT(bp,(int)NULL);
                
                header=bp;
            }
	    // return header;
            
        }else if(pre2==current1)
        {
            if(pre1==NULL && next2==NULL)
            {
                 PUT(bp,(int)NULL);
                 PUT(NEXT(bp),(int)NULL);
                 
                 header=bp;
            }
            else if(pre1!=NULL && next2==NULL)
            {
                PUT(NEXT(pre1),(int)NULL);
                
                PUT(header,(int)bp);
                PUT(bp,(int)NULL);
                
                PUT(NEXT(bp),(int)header);
                
                header=bp;
                
            }
            else if(pre1==NULL && next2!=NULL)
            {
                PUT(next2,(int)bp);
                PUT(NEXT(bp),(int)next2);
                PUT(bp,(int)NULL);
                
                header=bp;
            }
            else
            {
                
                PUT(NEXT(pre1),(int)next2);
                PUT(next2,(int)pre1);
                
                PUT(header,(int)bp);
                PUT(bp,(int)NULL);
                PUT(NEXT(bp),(int)header);
                
                header=bp;         
                
            }
	    // return header;
            
            
        }
        else
        {
            if(pre1==NULL)
            {
                if(next2==NULL)
                {
                    PUT(NEXT(pre2),(int)NULL);
                    
                    
                }
                else
                {
                    PUT(NEXT(pre2),(int)next2);
                    PUT(next2,(int)pre2);
                }
                
                PUT(bp,(int)NULL);
                PUT(NEXT(bp),(int)next1);
                PUT(next1,(int)bp);
                
                header=bp;
                
                
            }

            else if(pre2==NULL)
            {
                if(next1==NULL)
                {
                    PUT(NEXT(pre1),(int)NULL);
                    
                }
                else
                {
                    PUT(NEXT(pre1),(int)next1);
                    PUT(next1,(int)pre1);                  
                }
                
                PUT(bp,(int)NULL);
                PUT(next2,(int)bp);
                PUT(NEXT(bp),(int)next2);
                header=bp;
                
                
            }
            else
            {
                if(next1==NULL)
                {
                    PUT(NEXT(pre2),(int)next2);
                    PUT(next2,(int)pre2);
                    PUT(NEXT(pre1),(int)NULL);
                }
                else if (next2==NULL)
                {
                    PUT(NEXT(pre1),(int)next1);
                    PUT(next1,(int)pre1);
                    
                    PUT(NEXT(pre2),(int)NULL);
                }
                else
                {
                     PUT(NEXT(pre2),(int)next2);
                     PUT(next2,(int)pre2);
                     
                     PUT(NEXT(pre1),(int)next1);
                     PUT(next1,(int)pre1);
                    
                }

                PUT(bp,(int)NULL);
                PUT(header,(int)bp);
                
                PUT(NEXT(bp),(int)header);
                header=bp;

                
               
            }

               
	    // return header;          
        }
        
    }
    
    if (largest_size < GET_SIZE(HDRP(header)))
    {
	largest_size = GET_SIZE(HDRP(header));
	largest_changed = 0;
	largest_ptr = header;
    }
    return header;
}

static void *find_fit(size_t asize)
{
    void *bp;
    
   
    //to find the poperiate fit
   
       
    for(bp=header;bp!=NULL;bp=(void *)(GET(NEXT(bp))))
    {
       
            if(asize<=GET_SIZE(HDRP(bp)))
            {
              
                return bp;
            }
            
            //  printf("the bad pointer is %p\n",bp);
    }
        return NULL;
}

static void place(void *bp,size_t asize)
{
    size_t csize = GET_SIZE(HDRP(bp));

    void *next=(void *)(GET(NEXT(bp)));
    void *pre=(void *)(GET(bp));
    
    if (GET_SIZE(HDRP(bp)) >= largest_size)
	largest_changed = 1;
    
    PUT(bp,(int)NULL);
    PUT(NEXT(bp),(int)NULL);

    if((csize - asize) >= (DSIZE + OVERHEAD))
    {
        PUT(HDRP(bp),PACK(asize,1));
        PUT(FTRP(bp),PACK(asize,1));
        bp=NEXT_BLKP(bp);

        PUT(HDRP(bp),PACK(csize - asize ,0));
        PUT(FTRP(bp),PACK(csize - asize ,0));

        if(pre!=NULL && next!=NULL)
        {
            
            PUT(NEXT(pre),(int)next);
            PUT(next,(int)pre);
            
            PUT(NEXT(bp),(int)header);
            PUT(header,(int)bp);
            PUT(bp,(int)NULL);
            
            header=bp;
        }
        else if(pre==NULL && next!=NULL)
        {
            PUT(bp,(int)NULL);
            
            PUT(NEXT(bp),(int)next);
            PUT(next,(int)bp);
            header=bp;
        }
        else if (pre!=NULL && next==NULL)
        {
            PUT(NEXT(pre),(int)NULL);
            
            PUT(bp,(int)NULL);
            PUT(NEXT(bp),(int)header);
            PUT(header,(int)bp);
            header=bp;
            
        }
        else
        {
            PUT(bp,(int)NULL);
            PUT(NEXT(bp),(int)NULL);
            header=bp;
            
        }

    }
    else
    {
        PUT(HDRP(bp),PACK(csize,1));
        PUT(FTRP(bp),PACK(csize,1));
        
        if(pre!=NULL && next!=NULL)
        {
            PUT(NEXT(pre),(int)next);
            PUT(next,(int)pre);
        }
        else if(pre==NULL && next!=NULL)
        {
            header=next;
            PUT(header,(int)NULL);
            
        }
        else if(pre!=NULL && next==NULL)
        {
            PUT(NEXT(pre),(int)NULL);
        }

        else
        {
            header=NULL;
            

      }
        
        
        
    }
    
    
}

static void copy(void *aim,void * from,size_t size)
{
    int j;
    for (j = 0; j < size; j++)
	*((char *) aim + j) = 0;
}