Natools

   overriding procedure Read
     (Buffer : in out Atom_Buffer;
      Item : out Ada.Streams.Stream_Element_Array;
      Last : out Ada.Streams.Stream_Element_Offset) is
   begin
      if Item'Length < Buffer.Used then
         declare
            Mutator : constant Atom_Refs.Mutator := Buffer.Ref.Update;
         begin
         Last := Item'Last;
         Item := Buffer.Ref.Query.Data.all (1 .. Item'Length);
         Buffer.Used := Buffer.Used - Item'Length;
            Last := Item'Last;
            Item := Mutator.Data.all (1 .. Item'Length);
            Buffer.Used := Buffer.Used - Item'Length;
            Mutator.Data.all (1 .. Buffer.Used) := Mutator.Data.all
              (Item'Length + 1 .. Item'Length + Buffer.Used);
         end;
      else
         Last := Item'First + Buffer.Used - 1;
         Item (Item'First .. Last)
           := Buffer.Ref.Query.Data.all (1 .. Buffer.Used);
         Buffer.Used := 0;
      end if;
   end Read;

end Natools.S_Expressions.Atom_Buffers;