lib-sort.adb   [plain text]


------------------------------------------------------------------------------
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------------------------------------------------------------------------------

with GNAT.Heap_Sort_A; use GNAT.Heap_Sort_A;

separate (Lib)
procedure Sort (Tbl : in out Unit_Ref_Table) is

   T : array (0 .. Integer (Tbl'Last - Tbl'First + 1)) of Unit_Number_Type;
   --  Actual sort is done on this copy of the array with 0's origin
   --  subscripts. Location 0 is used as a temporary by the sorting algorithm.
   --  Also the addressing of the table is more efficient with 0's origin,
   --  even though we have to copy Tbl back and forth.

   function Lt_Uname (C1, C2 : Natural) return Boolean;
   --  Comparison routine for comparing Unames. Needed by the sorting routine

   procedure Move_Uname (From : Natural; To : Natural);
   --  Move routine needed by the sorting routine below

   --------------
   -- Lt_Uname --
   --------------

   function Lt_Uname (C1, C2 : Natural) return Boolean is
   begin
      --  Preprocessing data and definition files are not sorted, they are
      --  at the bottom of the list. They are recognized because they are
      --  the only ones without a Unit_Name.

      if Units.Table (T (C1)).Unit_Name = No_Name then
         return False;

      elsif Units.Table (T (C2)).Unit_Name = No_Name then
         return True;

      else
         return
           Uname_Lt
             (Units.Table (T (C1)).Unit_Name, Units.Table (T (C2)).Unit_Name);
      end if;
   end Lt_Uname;

   ----------------
   -- Move_Uname --
   ----------------

   procedure Move_Uname (From : Natural; To : Natural) is
   begin
      T (To) := T (From);
   end Move_Uname;

--  Start of processing for Sort

begin
   if T'Last > 0 then
      for I in 1 .. T'Last loop
         T (I) := Tbl (Int (I) - 1 + Tbl'First);
      end loop;

      Sort (T'Last,
        Move_Uname'Unrestricted_Access, Lt_Uname'Unrestricted_Access);

   --  Sort is complete, copy result back into place

      for I in 1 .. T'Last loop
         Tbl (Int (I) - 1 + Tbl'First) := T (I);
      end loop;
   end if;
end Sort;