gcc/ada/g-busorg.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUNTIME COMPONENTS                          --
   4 --                                                                          --
   5 --                   G N A T . B U B B L E _ S O R T _ G                    --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --           Copyright (C) 1995-2002 Ada Core Technologies, Inc.            --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  Bubblesort generic package using formal procedures
  35
  36 --  This package provides a generic bubble sort routine that can be used with
  37 --  different types of data.
  38
  39 --  See also GNAT.Bubble_Sort, a version that works with subprogram access
  40 --  parameters, allowing code sharing. The generic version is slightly more
  41 --  efficient but does not allow code sharing and has an interface that is
  42 --  more awkward to use. The generic version is also Pure, while the access
  43 --  subprograqm version can only be Preelaborate.
  44
  45 --  There is also GNAT.Bubble_Sort_A, which is now considered obsolete, but
  46 --  was an older version working with subprogram parameters. This version
  47 --  is retained for bacwards compatibility with old versions of GNAT.
  48
  49 generic
  50    --  The data to be sorted is assumed to be indexed by integer values from
  51    --  1 to N, where N is the number of items to be sorted. In addition, the
  52    --  index value zero is used for a temporary location used during the sort.
  53
  54    with procedure Move (From : Natural; To : Natural);
  55    --  A procedure that moves the data item with index value From to the data
  56    --  item with index value To (the old value in To being lost). An index
  57    --  value of zero is used for moves from and to a single temporary location
  58    --  used by the sort.
  59
  60    with function Lt (Op1, Op2 : Natural) return Boolean;
  61    --  A function that compares two items and returns True if the item with
  62    --  index Op1 is less than the item with Index Op2, and False if the Op2
  63    --  item is greater than or equal to the Op1 item.
  64
  65 package GNAT.Bubble_Sort_G is
  66 pragma Pure (Bubble_Sort_G);
  67
  68    procedure Sort (N : Natural);
  69    --  This procedures sorts items in the range from 1 to N into ascending
  70    --  order making calls to Lt to do required comparisons, and Move to move
  71    --  items around. Note that, as described above, both Move and Lt use a
  72    --  single temporary location with index value zero. This sort is stable,
  73    --  that is the order of equal elements in the input is preserved.
  74
  75 end GNAT.Bubble_Sort_G;