-- File:	IGESData_ReadWriteModule.cdl
-- Created:	Mon Sep  6 19:22:12 1993
-- Author:	Christian CAILLET
--		<cky@bravox>
---Copyright:	 Matra Datavision 1993



deferred class ReadWriteModule  from IGESData
      inherits ReaderModule from Interface

    ---Purpose : Defines basic File Access Module, under the control of
    --           IGESReaderTool for Reading and IGESWriter for Writing :
    --           Specific actions concern : Read and Write Own Parameters of
    --           an IGESEntity.           
    --           The common parts (Directory Entry, Lists of Associativities
    --           and Properties) are processed by IGESReaderTool & IGESWriter
    --           
    --           Each sub-class of ReadWriteModule is used in conjunction with
    --           a sub-class of Protocol from IGESData and processes several
    --           types of IGESEntity (typically, them of a package) :
    --           The Protocol gives a unique positive integer Case Number for
    --           each type of IGESEntity it recognizes, the corresponding
    --           ReadWriteModule processes an Entity by using the Case Number
    --           to known what is to do
    --           On Reading, the general service NewVoid is used to create an
    --           IGES Entity the first time
    --           
    --  Warning : Works with an IGESReaderData which stores "DE parts" of Items

uses Transient, FileReaderData, Check,
     IGESEntity, DirPart, IGESReaderData, ParamReader, IGESWriter

raises DomainError

is

    CaseNum (me; data : FileReaderData; num : Integer) returns Integer;
    ---Purpose : Translates the Type of record <num> in <data> to a positive
    --           Case Number, or 0 if failed.
    --           Works with IGESReaderData which provides Type & Form Numbers,
    --           and calls CaseIGES (see below)

    CaseIGES (me; typenum, formnum : Integer) returns Integer  is deferred;
    ---Purpose : Defines Case Numbers corresponding to the Entity Types taken
    --           into account by a sub-class of ReadWriteModule (hence, each
    --           sub-class of ReadWriteModule has to redefine this method)
    --           Called by CaseNum. Its result will then be used to call
    --           Read, etc ...

    Read (me; CN : Integer; data : FileReaderData; num : Integer;
    	ach : in out Check; ent : mutable Transient)
    	raises DomainError;
    ---Purpose : General Read Function. See IGESReaderTool for more info

    ReadOwnParams (me; CN : Integer; ent : mutable IGESEntity;
    	    	   IR : IGESReaderData; PR : in out ParamReader)
    	raises DomainError  is deferred;
    ---Purpose : Reads own parameters from file for an Entity; <PR> gives
    --           access to them, <IR> detains parameter types and values
    --           For each class, there must be a specific action provided
    --           Note that Properties and Associativities Lists are Read by
    --           specific methods (see below), they are called under control
    --           of reading process (only one call) according Stage recorded
    --           in ParamReader


    WriteOwnParams (me; CN : Integer; ent : IGESEntity;
    	    	    IW : in out IGESWriter)
	is deferred;
    ---Purpose : Writes own parameters to IGESWriter; defined for each class
    --           (to be redefined for other IGES ReadWriteModules)
    --  Warning : Properties and Associativities are directly managed by
    --           WriteIGES, must not be sent by this method

end ReadWriteModule;