mm_0.c

ICS 课程的Lab7

                {
                     newptr=mm_malloc(size);
                     memcpy(newptr,oldptr,oldsize-DSIZE);
                     mm_free(oldptr);
                     return newptr;
                    
                }
                
                
                
            }
            
            
            
            
            
            
        }
        
    }
    
        
      
}



void *mm_malloc(size_t size)
{
    size_t asize;
    size_t extendsize;
    void  *bp;
    
    j++;
    
    
    if(size<=0)
    {
        return NULL;
    }

    if(size <= DSIZE)
    {
        asize = DSIZE + OVERHEAD;
        
    }else
    {
        asize = DSIZE *((size +(OVERHEAD) + (DSIZE - 1))/DSIZE);
    }
    if((bp = find_fit(asize)) !=NULL)
    {
        
        return place(bp,asize);

    }

    extendsize = MAX(asize,CHUNKSIZE);

    if((bp = extend_heap(extendsize/WSIZE)) == NULL)
    {

        return NULL;
    }

   return  place(bp,asize);
    
}
static void *coalesce(void *bp)
{
    size_t prev_alloc = GET_ALLOC(FTRP(PREV_BLKP(bp)));
    size_t next_alloc = GET_ALLOC(HDRP(NEXT_BLKP(bp)));
    size_t size       = GET_SIZE(HDRP(bp));

    void *temp1;
    void *temp2;
    
   
    
    if(prev_alloc && next_alloc)
    {
     	if(header==NULL)
    	{
	       PUT(bp,(int)NULL);
	       PUT(NEXT(bp),(int)NULL);
	       tail=header=bp;
    	}
	else
	{
	    if(bp<header)
	    {
            PUT(bp,(int)NULL);
            PUT(NEXT(bp),(int)header);
            PUT(header,(int)bp);
            header=bp;
		
	    }
        
	    for(temp1=header;temp1!=NULL;temp1=(void *)(GET(NEXT(temp1))))
	    {
             
		temp2=(void *)(GET(NEXT(temp1)));
		if(temp2!=NULL)
		{
		    if(bp>temp1 &&bp<temp2)
		    {
			PUT(NEXT(temp1),(int)(bp));
			PUT(bp,(int)temp1);
			
			PUT(NEXT(bp),(int)temp2);
			PUT(temp2,(int)bp);

			return bp;
		    }
		}
		else
		{
		    if(bp>temp1)
		    {
                        PUT(NEXT(temp1),(int)bp);
                        PUT(bp,(int)temp1);
                        PUT(NEXT(bp),(int)NULL);
                        tail=bp;
		    }


                  }
	    }
        
	    
	}
        return bp;
    }
    else if(prev_alloc && !next_alloc)
    {


    	void *nextBp=NEXT_BLKP(bp);
     
        size += GET_SIZE(HDRP(NEXT_BLKP(bp)));
        PUT(HDRP(bp),PACK(size,0));
        PUT(FTRP(bp),PACK(size,0));
	
        temp1=(void *)(GET(nextBp));
        temp2=(void *)(GET(NEXT(nextBp)));


       
	
        PUT(nextBp,(int)NULL);
        PUT(NEXT(nextBp),(int)NULL);
	
	if(temp1==NULL && temp2==NULL)
	{ 
	    PUT(bp,(int)NULL);
	    PUT(NEXT(bp),(int)NULL);
	    tail=header=bp;
	    
	}else if(temp1!=NULL && temp2==NULL)

        {
	    PUT(NEXT(temp1),(int)bp);
	    PUT(bp,(int)temp1);
	    PUT(NEXT(bp),(int)NULL);
        tail=bp;
	    
	}else if(temp1==NULL && temp2!=NULL)

	  {	 
	    PUT(NEXT(bp),(int)temp2);
	    PUT(temp2,(int)bp);
	    PUT(bp,(int)NULL);
	    
	    header=bp;
	    
	}else
	{
	   
	     PUT(NEXT(temp1),(int)bp);
	     PUT(bp,(int)temp1);
             PUT(temp2,(int)bp);
	     PUT(NEXT(bp),(int)temp2);

	  
	    
	}
	
      
        return bp;
    }
    else if(!prev_alloc && next_alloc)
    {

        size += GET_SIZE(HDRP(PREV_BLKP(bp)));
        PUT(FTRP(bp),PACK(size,0));
        PUT(HDRP(PREV_BLKP(bp)),PACK(size,0));

        return PREV_BLKP(bp);
        
    }else
    {
       
            void *pre=PREV_BLKP(bp);
            void *next=NEXT_BLKP(bp);
            void *next1=(void *)(GET(NEXT(next)));
            PUT(next,(int)NULL);
	        PUT(NEXT(next),(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));

       
        if(next1==NULL)
	{
	    PUT(NEXT(pre),(int)NULL);
            tail=pre;
	}
	else
	{
	    PUT(NEXT(pre),(int)next1);
	    PUT(next1,(int)pre);
	    
	}

	return pre;
        
    }
    
    
    
    
    
}

static void *find_fit(size_t asize)
{
    void *bp;

    if(header==NULL)
    {
    	return NULL;
    }

    
    if(j%2==1)
    {
       
            
        
        for(bp=header;bp!=NULL;bp=(void *)(GET(NEXT(bp))))
      {
    	if(asize<=GET_SIZE(HDRP(bp)))
    	{
	    
             return bp;
    	}
    


      }
        
        
    }else
    {
        if(tail==NULL)
        {
            return NULL;
            
        }
      
        
         for(bp=tail;bp!=NULL;bp=(void *)(GET(bp)))
      {
    	if(asize<=GET_SIZE(HDRP(bp)))
    	{
	    
             return bp;
    	}
        
      }
       
    }
    
         

  
    
        
        
        
    
    
    
   
    
    
    return NULL;
    
    
}

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

    void *result;

    if((csize - asize) >= (DSIZE + OVERHEAD))
    {
             
	if(j%2==1)
    {
	    
	
	 PUT(bp,(int)NULL);
	 PUT(NEXT(bp),(int)NULL);
	     
	 PUT(HDRP(bp),PACK(asize,1));
     PUT(FTRP(bp),PACK(asize,1));

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


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

	 PUT(NEXT(pre),(int)bp);
         PUT(bp,(int)pre);
	    
	 PUT(NEXT(bp),(int)next);
	 PUT(next,(int)bp);
	    
	}

      return result;
		}
		else
		{
            PUT(HDRP(bp),PACK(csize-asize,0));
        	PUT(FTRP(bp),PACK(csize-asize,0));
        	bp=NEXT_BLKP(bp);

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

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

    
     
     
   return bp;
    
}