-- File:	STEPConstruct_UnitContext.cdl
-- Created:	Thu Jan 18 15:16:52 1996
-- Author:	Frederic MAUPAS
--		<fma@pronox>
---Copyright:	 Matra Datavision 1996

class UnitContext from STEPConstruct
   
    	---Purpose: Tool for creation (encoding) and decoding (for writing and reading
	--          accordingly) context defining units and tolerances (uncerntanties)
   
uses
    SiUnit    from StepBasic,
    SiPrefix  from StepBasic,
    NamedUnit from StepBasic,
    GlobalUnitAssignedContext        from StepRepr,
    GlobalUncertaintyAssignedContext from StepRepr,
    GeomRepContextAndGlobUnitAssCtxAndGlobUncertaintyAssCtx from StepGeom
   
is
    Create returns UnitContext;
    	---Purpose: Creates empty tool
       
    Init (me: in out; Tol3d: Real);
    	---Purpose: Creates new context (units are MM and radians, 
        --          uncertainty equal to Tol3d)
       
    IsDone (me) returns Boolean;
    	---Purpose: Returns True if Init was called successfully
       
    Value (me) returns GeomRepContextAndGlobUnitAssCtxAndGlobUncertaintyAssCtx from StepGeom;
    	---Purpose: Returns context (or Null if not done)
       
    ComputeFactors(me: in out; aContext: GlobalUnitAssignedContext from StepRepr)
    returns Integer;
    	---Purpose: Computes the length, plane angle and solid angle conversion
    	--          factor  .  Returns a status, 0 if OK
    
    ComputeFactors(me: in out; aUnit: NamedUnit from StepBasic)
    returns Integer;

    ComputeTolerance(me: in out; aContext: GlobalUncertaintyAssignedContext from StepRepr)
    returns Integer;
	---Purpose : Computes the uncertainty value (for length)

    LengthFactor(me) returns Real;
    	---Purpose: Returns the lengthFactor

    PlaneAngleFactor(me) returns Real;
    	---Purpose: Returns the planeAngleFactor

    SolidAngleFactor(me) returns Real;
    	---Purpose: Returns the solidAngleFactor

    Uncertainty(me) returns Real;
    	---Purpose: Returns the Uncertainty value (for length)
    	--          It has been converted  with LengthFactor
    
    AreaFactor(me) returns Real;
    	---Purpose: Returns the areaFactor
    
    VolumeFactor(me) returns Real;
    	---Purpose: Returns the volumeFactor

    HasUncertainty(me) returns Boolean;
    	---Purpose: Tells if a Uncertainty (for length) is recorded

    LengthDone(me) returns Boolean;
    	---Purpose: Returns true if ComputeFactors has calculated
    	--          a LengthFactor

    PlaneAngleDone(me) returns Boolean;
    	---Purpose: Returns true if ComputeFactors has calculated
    	--          a PlaneAngleFactor

    SolidAngleDone(me) returns Boolean;
    	---Purpose: Returns true if ComputeFactors has calculated
    	--          a SolidAngleFactor
    
    AreaDone(me) returns Boolean;
    	---Purpose: Returns true if areaFactor is computed
    
    VolumeDone(me) returns Boolean;
    	---Purpose: Returns true if volumeFactor is computed

    SiUnitNameFactor(me; aSiUnit : SiUnit from StepBasic; val : out Real) 
    returns Boolean is private;
    	---Purpose: Fills numerical equivalent of SiUnitName (in SI value)
    	--          Returns False if name SiUnit Name not recognized

    StatusMessage (me; status :Integer) returns CString;
    	---Purpose: Returns a message for a given status (0 - empty)
    	--          This message can then be added as warning for transfer

    ConvertSiPrefix (myclass; aPrefix: SiPrefix from StepBasic) returns Real;
        ---Purpose: Convert SI prefix defined by enumertaion to corresponding 
        --          real factor (e.g. 1e6 for mega)

fields

    -- writing (encoding)
    done: Boolean;
    GRC : GeomRepContextAndGlobUnitAssCtxAndGlobUncertaintyAssCtx from StepGeom;
    
    -- reading (decoding)
    lengthFactor     : Real;
    planeAngleFactor : Real;
    solidAngleFactor : Real;
    theUncertainty   : Real;
    areaFactor       : Real;
    volumeFactor     : Real;
    areaDone         : Boolean;
    volumeDone       : Boolean;
    lengthDone       : Boolean;
    planeAngleDone   : Boolean;
    solidAngleDone   : Boolean;
    hasUncertainty   : Boolean;
   
end UnitContext;