gcc/ada/lib-sort.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                             L I B . S O R T                              --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --                                                                          --
  10 --   Copyright (C) 1992,1993,1994,1995,1996 Free Software Foundation, Inc.  --
  11 --                                                                          --
  12 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNAT was originally developed  by the GNAT team at  New York University. --
  31 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 with GNAT.Heap_Sort_A; use GNAT.Heap_Sort_A;
  36
  37 separate (Lib)
  38 procedure Sort (Tbl : in out Unit_Ref_Table) is
  39
  40    T : array (0 .. Integer (Tbl'Last - Tbl'First + 1)) of Unit_Number_Type;
  41    --  Actual sort is done on this copy of the array with 0's origin
  42    --  subscripts. Location 0 is used as a temporary by the sorting algorithm.
  43    --  Also the addressing of the table is more efficient with 0's origin,
  44    --  even though we have to copy Tbl back and forth.
  45
  46    function Lt_Uname (C1, C2 : Natural) return Boolean;
  47    --  Comparison routine for comparing Unames. Needed by the sorting routine.
  48
  49    procedure Move_Uname (From : Natural; To : Natural);
  50    --  Move routine needed by the sorting routine below.
  51
  52    --------------
  53    -- Lt_Uname --
  54    --------------
  55
  56    function Lt_Uname (C1, C2 : Natural) return Boolean is
  57    begin
  58       return
  59         Uname_Lt
  60           (Units.Table (T (C1)).Unit_Name, Units.Table (T (C2)).Unit_Name);
  61    end Lt_Uname;
  62
  63    ----------------
  64    -- Move_Uname --
  65    ----------------
  66
  67    procedure Move_Uname (From : Natural; To : Natural) is
  68    begin
  69       T (To) := T (From);
  70    end Move_Uname;
  71
  72 --  Start of processing for Sort
  73
  74 begin
  75    if T'Last > 0 then
  76       for I in 1 .. T'Last loop
  77          T (I) := Tbl (Int (I) - 1 + Tbl'First);
  78       end loop;
  79
  80       Sort (T'Last,
  81         Move_Uname'Unrestricted_Access, Lt_Uname'Unrestricted_Access);
  82
  83    --  Sort is complete, copy result back into place
  84
  85       for I in 1 .. T'Last loop
  86          Tbl (Int (I) - 1 + Tbl'First) := T (I);
  87       end loop;
  88    end if;
  89 end Sort;