DEFINITION MODULE Storage;
(*
  Module:	Dynamic storage allocation
  From:		"Programming in Modula-2", 3rd, corrected edition, by N. Wirth
  Version:	$Header$
*)

(*
  Wirth's 3rd edition certainly is confusing: mostly it uses Allocate, but
  the module at the end of the book defines ALLOCATE. To avoid problems,
  I included them both.
*)

	FROM SYSTEM IMPORT ADDRESS;

	PROCEDURE ALLOCATE(VAR a : ADDRESS; size : CARDINAL);
	(* Allocate an area of the given size and return the address
	   in "a". If no space is available, the calling program is
	   killed.
	*)

	PROCEDURE Allocate(VAR a : ADDRESS; size : CARDINAL);
	(* Identical to ALLOCATE *)

	PROCEDURE DEALLOCATE(VAR a : ADDRESS; size : CARDINAL);
	(* Free the area at address "a" with the given size. The area
	   must have been allocated by "ALLOCATE", with the same size.
	*)

	PROCEDURE Deallocate(VAR a : ADDRESS; size : CARDINAL);
	(* Identical to DEALLOCATE *)

	PROCEDURE Available(size : CARDINAL) : BOOLEAN;
	(* Return TRUE if an area with the given size could be allocated.
	*)

END Storage.