这只是个简单的记录。其实使用流程图更好一些，但是我懒得做了。

void *realloc(void *ptr, int bytes);

void *newp;
int nb = request2size(bytes);
int oldsize = chunksize(ptr);

• if(bytes == 0)
  1. free(oldp)
  2. return(0)
• if(ptr == NULL)
  1. newp = malloc(bytes)
  2. return(newp)
• else
  • if(oldsize >= nb)
    • GOTO:Split
  • if(use_topbin)
    1. split(top)
    2. merge(ptr, top)
    3. return(newp)
  • if(!inuse(next_chunk))
    1. unlink(next_chunk)
    2. merge(ptr, next_chunk)
    3. GOTO:Split
  • other
    1. newp = malloc(nb - MALLOC_ALIGN_MASK)
    2. if(newp == next_chunk)
       • GOTO:Split
    3. memcpy(ptr, newp, size)
    4. free(ptr)
    5. return(newp)
• Split
  • if(remainder < MIN_SIZE)
    1. set_head(newp)
    2. return(newp)
  • else
    1. split(remainder)
    2. set_head(remainder)
    3. set_head(newp)
    4. free(remainder)
    5. return(newp)