Path: utzoo!attcan!uunet!zephyr.ens.tek.com!tektronix!nosun!qiclab!m2xenix!puddle!f101.n273.z1.fidonet.org!Peter.M..Perchansky
From: Peter.M..Perchansky@f101.n273.z1.fidonet.org (Peter M. Perchansky)
Newsgroups: comp.lang.modula2
Subject: Generic Lists in Modula-2
Message-ID: <462.26C2767E@puddle.fidonet.org>
Date: 9 Aug 90 03:42:22 GMT
Sender: ufgate@puddle.fidonet.org (newsout1.26)
Organization: FidoNet node 1:273/101 - Schizophrenia, Fleetwood PA
Lines: 108

DEFINITION MODULE PMPDeque;

(*---------- Procedures from JPI's TopSpeed Modula II -------------*)
FROM SYSTEM IMPORT BYTE;
(*-----------------------------------------------------------------*)

TYPE
    Deques;           (* opaque type defined in implementation module *)
    DequesStatus   = (empty, full, mismatchedSize, noSuchNode, none);
    ErrorHandler   = PROCEDURE (DequesStatus);

(*  DequesStatus code explainations: *)
(*    empty:           An operation tried to remove/show data from *)
(*                     an empty deque. *)
(*    full:            An operation tried to add data to a full *)
(*                     deque; no more memory available. *)
(*    mismatchedSize:  An operation tried to remove/show data to a *)
(*                     variable whose size (in bytes) did not match *)
(*                     the size of the variable stored in the deque. *)
(*    noSuchNode:      An operation tried to process a node that does *)
(*                     not exist in the deque. *)
(*    none:            No error occured during processing. *)

PROCEDURE CreateDeque (VAR deque: Deques);
(* Creates the deque by making it NIL *)
(* This procedure must be called prior to performing operations on *)
(* the deque. *)

PROCEDURE Empty (deque: Deques): BOOLEAN;
(* Return TRUE if the deque is NIL (empty). *)

PROCEDURE DestroyDeque (VAR deque: Deques);
(* Destroys the deque by deallocating deque nodes and contents *)
(* DestroyDeque should be called when the deque is no longer needed *)
(* in memory. *)

PROCEDURE Full (size: CARDINAL): BOOLEAN;
(* Return TRUE if there is no Available memory for another deque node *)

PROCEDURE DequeLength (deque: Deques): CARDINAL;
(* Returns the number of nodes in the deque *)

PROCEDURE DequePos (data: ARRAY OF BYTE; deque: Deques): CARDINAL;
(* Returns the number of the node containing the data (if found). *)
(* Returns 0 if not found.  The front of the deque is treated as node *)
(* number one. *)

PROCEDURE InDeque (data: ARRAY OF BYTE; deque: Deques): BOOLEAN;
(* Returns TRUE if data is found in deque. *)

PROCEDURE LastError (): DequesStatus;
(* Returns the status code containing the last error (if any) from a *)
(* previous operation. *)

PROCEDURE InstallErrorHandler (handler: ErrorHandler);
(* Installs client-module error procedure to handle errors that occur *)
(* during deque operations.  Until an error-handler is installed, all *)
(* errors will be ignored. *)

PROCEDURE Enqueue (data: ARRAY OF BYTE; VAR deque: Deques);
(* Place data in node at the back of the deque.  status is set to *)
(* full or none. *)

PROCEDURE Push (data: ARRAY OF BYTE; VAR deque: Deques);
(* Place data in node at the back of the deque.  status is set to *)
(* full or none. *)

PROCEDURE Dequeue (VAR data: ARRAY OF BYTE; VAR deque: Deques);
(* Place contents from node at the front of the deque into data. *)
(* Remove the front node of the deque.  status is set to empty, *)
(* mismatchedSize, or none. *)

PROCEDURE Pop (VAR data: ARRAY OF BYTE; VAR deque: Deques);
(* Place contents from node at the back of the deque into data. *)
(* Remove the back node of the deque.  status is set to empty, *)
(* mismatchedSize, or none. *)

PROCEDURE Update (data: ARRAY OF BYTE; nthItem: CARDINAL; VAR deque: Deques);
(* Update contents of nth node of the deque from data.  status is set *)
(* to empty, mismatchedSize, noSuchNode, or none. *)

PROCEDURE Serve (VAR data: ARRAY OF BYTE; nthItem: CARDINAL; VAR deque: Deques);
(* Place contents from nth node of the deque into data.  Remove the *)
(* nth node of the deque.  status is set to empty, mismatchedSize, *)
(* noSuchNode, or none. *)

PROCEDURE Front (VAR data: ARRAY OF BYTE; deque: Deques);
(* Place contents from node at the front of the deque into data. *)
(* status is set to empty, mismatchedSize, or none. *)

PROCEDURE Back (VAR data: ARRAY OF BYTE; deque: Deques);
(* Place contents from node at the back of the deque into data. *)
(* status is set to empty, mismatchedSize, or none. *)

PROCEDURE Top (VAR data: ARRAY OF BYTE; deque: Deques);
(* Place contents from node at the back (top) of the deque into data. *)
(* status is set to empty, mismatchedSize, or none. *)

PROCEDURE Retrieve (VAR data: ARRAY OF BYTE; nthItem: CARDINAL; deque: Deques);
(* Place contents from nth node of the deque into data.  status is *)
(* set to empty, mismatchedSize, noSuchNode, or none. *)

END PMPDeque.


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