DEFINITION MODULE Storage;
(*
        Standard dynamic storage management


Derived from the Lilith Modula-2 system developed by the
group of Prof. N. Wirth at ETH Zurich, Switzerland.


  Storage management for dynamic variables. Calls to the
  Modula-2 standard procedures NEW and DISPOSE are translated
  into calls to ALLOCATE and DEALLOCATE. The standard way to
  provide these two procedures is to import them from this
  module 'Storage'.
*)

FROM SYSTEM IMPORT ADDRESS;

EXPORT QUALIFIED
    ALLOCATE, DEALLOCATE, Available, InstallHeap, RemoveHeap;


PROCEDURE ALLOCATE (VAR a: ADDRESS; size: CARDINAL);
(*- Allocate some dynamic storage.
in:     size    number of bytes to allocate,
out:    a       ADDRESS of allocated storage.

The actual number of bytes allocated may be slightly greater
than 'size', due to administrative overhead.
If not enough space is available, the calling program is
terminated with the status 'heapovf'.
*)

PROCEDURE DEALLOCATE (VAR a: ADDRESS; size: CARDINAL);
(*- Release some dynamic storage.
in:     a       ADDRESS of the area to release,
        size    number of bytes to be released,
out:    a       set to NIL.
*)

PROCEDURE Available (size: CARDINAL) : BOOLEAN;
(*- Test whether some number of bytes could be allocated.
in:     size    number of bytes
out:    TRUE if ALLOCATE(p,size) would succeed.
*)

PROCEDURE InstallHeap;
(*- Used by the loader -*)

PROCEDURE RemoveHeap;
(*- Used by the loader -*)

END Storage.
