Algorithm 1 Single Array Allocate and Free Objects

Require: An array $A$ representing all doubly linked list nodes and variable $free$ indicating the head of free list

1:procedure AllocateObject()

2:if $free == NIL$ then

3:error "out of space"

4:else

5: $x = free$

6: $free = A[x + 1]$ // $A[x + 1]$ is conceptually $x.next$

7:return x

8:end if

9:end procedure

10:

11:procedure FreeObject( $x$ )

12: $A[x + 1] = free$ // $A[x + 1]$ is conceptually $x.next$

13: $free = x$

14:end procedure