NeverPas Outline - GFF Object

The GFF Object allows us to read and write GFF data to and from files, using a system similar to a 'state machine' for data access.

Consider the following (generalized) GFF Data.

Top Structure (FFFFFFFF)
  Label1	----------> String Data
  Label2  ----------> Integer
  Label3  ----------> Sub Structure (StructID 2)
    Label4 ----------> Integer
    Label5 ----------> Float
  Label6  ----------> Char

One method to read this data is to use a series of functions to get the data.
(the whitespace is to show how the state works)

  GFF.Open('mygffdata.gff');	// open the GFF file
  GFF.Verify('GFF','V3.2');	// verify that the GFF header/file is valid
  GFF.EnterStructure($FFFFFFFF);	// open the main structure
    MyString := GFF.GetString('Label1','DefaultString');	// read the string data by label name
    MyInteger1 := GFF.GetInteger('Label2',0);			// read the integer by label
    GFF.EnterStructure(2);	// enter the first structure in the current struct with StructID 2.
				// this always opens the first with the given StructID
      MyInteger2 := GFF.GetInteger('Label4',0);
      MyFloat := GFF.GetFloat('Label5',0.0);
    GFF.PreviousStructure;	// go back to parent structure
    MyChar := GFF.GetChar('Label6','A');
  GFF.Close;			// close the GFF file



The GFF class has a number of functions for retrieving GFF data.  They all follow these specifications:

	GFF.Get<DataType>(Label: String; Default: <datatype>): DataType;
	Examples:
		GFF.GetByte(Label:String; Default: Byte): Byte;
		GFF.GetFloat(Label: String; Default: Float): Float;
	The default parameter is /optional/.

	Special: GetBinary() is different, (using Binary instead of Void, to avoid confusion).
		GetBinary() returns a stream filled with the data.
		GetBinary(Label: String; Default: TStream): TStream;

The class also has the following functions:

	GFF NAVIGATION
	==============

	EnterStructure(StructID: DWORD);
		Enters the first structure inside the current structure with the given StructID.
		Legal GFF files shouldn't have more than one of the same Structure inside a single structure
		(remember, Lists are fields, not structures)

	EnterList(Label: String): DWORD;
		Enters a list inside the current structure. Returns the number of list elements.

	EnterListStructure(Index: DWord);
		Enters the structure in the list with the given index. Otherwise acts as EnterStructure

	ExitStructure();
		Returns to the current structure's parent. If at top level, this function does nothing.

	ExitList();
		Returns to the current list's parent structure.

	EnterTopLevelStructure();
		Sets the current structure to the top level parent structure that holds everything in the GFF.	


	GFF STRUCTURE
	=============
	GetLabels(var List: TStringList);
		Returns a list of strings for all the labels in the current structure. Used to make sure
		a field exists, or for use in GFF files where the contents are not known.

	GetStructures(var List: T