gcc/ada/libgnat/g-bubsor.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                     G N A T . B U B B L E _ S O R T                      --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --                     Copyright (C) 1995-2017, AdaCore                     --
  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 3,  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.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  Sort Utility (Using Bubblesort Algorithm)
  33
  34 --  This package provides a bubblesort routine that works with access to
  35 --  subprogram parameters, so that it can be used with different types with
  36 --  shared sorting code.
  37
  38 --  See also GNAT.Bubble_Sort_G and GNAT.Bubble_Sort_A. These are older
  39 --  versions of this routine. In some cases GNAT.Bubble_Sort_G may be a
  40 --  little faster than GNAT.Bubble_Sort, at the expense of generic code
  41 --  duplication and a less convenient interface. The generic version also
  42 --  has the advantage of being Pure, while this unit can only be Preelaborate.
  43
  44 package GNAT.Bubble_Sort is
  45    pragma Pure;
  46
  47    --  The data to be sorted is assumed to be indexed by integer values from
  48    --  1 to N, where N is the number of items to be sorted.
  49
  50    type Xchg_Procedure is access procedure (Op1, Op2 : Natural);
  51    --  A pointer to a procedure that exchanges the two data items whose
  52    --  index values are Op1 and Op2.
  53
  54    type Lt_Function is access function (Op1, Op2 : Natural) return Boolean;
  55    --  A pointer to a function that compares two items and returns True if
  56    --  the item with index value Op1 is less than the item with Index value
  57    --  Op2, and False if the Op1 item is greater than or equal to the Op2
  58    --  item.
  59
  60    procedure Sort (N : Natural; Xchg : Xchg_Procedure; Lt : Lt_Function);
  61    --  This procedures sorts items in the range from 1 to N into ascending
  62    --  order making calls to Lt to do required comparisons, and calls to
  63    --  Xchg to exchange items. The sort is stable, that is the order of
  64    --  equal items in the input is preserved.
  65
  66 end GNAT.Bubble_Sort;