-- File:	Interface_LineBuffer.cdl
-- Created:	Thu Apr 15 10:08:17 1993
-- Author:	Christian CAILLET
--		<cky@bravox>
---Copyright:	 Matra Datavision 1993


class LineBuffer  from Interface

    ---Purpose : Simple Management of a Line Buffer, to be used by Interface
    --           File Writers.
    --           While a String is suitable to do that, this class ensures an
    --           optimised Memory Management, because this is a hard point of
    --           File Writing.

uses Integer, Boolean, Character, CString,
     AsciiString from TCollection, HAsciiString from TCollection

raises OutOfRange

is

    Create (size : Integer = 10) returns LineBuffer;
    ---Purpose : Creates a LineBuffer with an absolute maximum size
    --           (Default value is only to satisfy compiler requirement)

    SetMax (me : in out; max : Integer)
    ---Purpose : Changes Maximum allowed size of Buffer.
    --           If <max> is Zero, Maximum size is set to the initial size.
    	raises OutOfRange  is static;
    --           Error if <max> is greater than <size> given at Creation time.

    SetInitial (me : in out; initial : Integer)
    ---Purpose : Sets an Initial reservation for Blank characters
    --           (this reservation is counted in the size of the current Line)
    	raises OutOfRange  is static;
    --           Error if <initial> is greater than current Maximum size

    SetKeep (me : in out)  is static;
    ---Purpose : Sets a Keep Status at current Length. It means that at next
    --           Move, the new line will begin by characters between Keep + 1
    --           and current Length

    CanGet (me : in out; more : Integer) returns Boolean  is static;
    ---Purpose : Returns True if there is room enough to add <more> characters
    --           Else, it is required to Dump the Buffer before refilling it
    --           <more> is recorded to manage SetKeep status

    Content (me) returns CString  is static;
    ---Purpose : Returns the Content of the LineBuffer
    -- was C++ : return const

    Length (me) returns Integer  is static;
    ---Purpose : Returns the Length of the LineBuffer

    Clear (me : in out)  is static;
    ---Purpose : Clears completely the LineBuffer

    FreezeInitial (me : in out) is static;
    ---Purpose : Inhibits effect of SetInitial until the next Move (i.e. Keep)
    --           Then Prepare will not insert initial blanks, but further ones
    --           will. This allows to cancel initial blanks on an internal Split
    --           A call to SetInitial has no effect on this until Move

    Prepare (me : in out)  is static private;
    ---Purpose : Prepares Move : Inserts Initial Blanks if required, and
    --           determines if SetKeep can be supported (it cannot be if Length
    --           + Next String to get (see CanGet) overpass Max Size)

    Keep (me : in out)  is static private;
    ---Purpose : Keeps characters from SetKeep. If SetKeep is Zero, equivalent
    --           to Clear

    Move (me : in out; str : in out AsciiString from TCollection)  is static;
    ---Purpose : Fills a AsciiString <str> with the Content of the Line Buffer,
    --           then Clears the LineBuffer

    Move (me : in out; str : mutable HAsciiString from TCollection)  is static;
    ---Purpose : Same as above, but <str> is known through a Handle

    Moved (me : in out) returns mutable HAsciiString from TCollection;
    ---Purpose : Same as above, but generates the HAsciiString


    Add (me : in out; text : CString)
    ---Purpose : Adds a text as a CString. Its Length is evaluated from the
    --           text (by C function strlen)
    	raises OutOfRange  is static;
    --           Error if there remains no room enough

    Add (me : in out; text : CString; lntext : Integer)
    ---Purpose : Adds a text as a CString. Its length is given as <lntext>
    	raises OutOfRange  is static;
    --           Error if there remains no room enough

    Add (me : in out; text : AsciiString from TCollection)
    ---Purpose : Adds a text as a AsciiString from TCollection
    	raises OutOfRange  is static;
    --           Error if there remains no room enough

    Add (me : in out; text : Character)
    ---Purpose : Adds a text made of only ONE Character
    	raises OutOfRange  is static;
    --           Error if there remains no room enough

fields

    theline : AsciiString from TCollection;
    themax  : Integer;
    theinit : Integer;
    thekeep : Integer;
    theget  : Integer;
    thelen  : Integer;
    thefriz : Integer;
    thekept : Character;

end LineBuffer;