1 ------------------------------------------------------------------------------
3 -- GNAT RUNTIME COMPONENTS --
5 -- G N A T . H E A P _ S O R T _ G --
11 -- Copyright (C) 1995-2000 Ada Core Technologies, Inc. --
13 -- GNAT is free software; you can redistribute it and/or modify it under --
14 -- terms of the GNU General Public License as published by the Free Soft- --
15 -- ware Foundation; either version 2, or (at your option) any later ver- --
16 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
17 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
18 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
19 -- for more details. You should have received a copy of the GNU General --
20 -- Public License distributed with GNAT; see file COPYING. If not, write --
21 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
22 -- MA 02111-1307, USA. --
24 -- As a special exception, if other files instantiate generics from this --
25 -- unit, or you link this unit with other files to produce an executable, --
26 -- this unit does not by itself cause the resulting executable to be --
27 -- covered by the GNU General Public License. This exception does not --
28 -- however invalidate any other reasons why the executable file might be --
29 -- covered by the GNU Public License. --
31 -- GNAT is maintained by Ada Core Technologies Inc (http://www.gnat.com). --
33 ------------------------------------------------------------------------------
35 -- Heapsort generic package using formal procedures
37 -- This package provides a generic heapsort routine that can be used with
38 -- different types of data. See also GNAT.Heap_Sort_A, a version that works
39 -- with subprogram parameters, allowing code sharing. The generic version
40 -- is slightly more efficient but does not allow code sharing. The generic
41 -- version is also Pure, while the access version can only be Preelaborate.
44 -- The data to be sorted is assumed to be indexed by integer values from
45 -- 1 to N, where N is the number of items to be sorted. In addition, the
46 -- index value zero is used for a temporary location used during the sort.
48 with procedure Move (From : Natural; To : Natural);
49 -- A procedure that moves the data item with index From to the data item
50 -- with Index To. An index value of zero is used for moves from and to a
51 -- single temporary location used by the sort.
53 with function Lt (Op1, Op2 : Natural) return Boolean;
54 -- A function that compares two items and returns True if the item with
55 -- index Op1 is less than the item with Index Op2, and False if the Op1
56 -- item is greater than or equal to the Op2 item.
58 package GNAT.Heap_Sort_G is
59 pragma Pure (Heap_Sort_G);
61 procedure Sort (N : Natural);
62 -- This procedures sorts items in the range from 1 to N into ascending
63 -- order making calls to Lt to do required comparisons, and Move to move
64 -- items around. Note that, as described above, both Move and Lt use a
65 -- single temporary location with index value zero. This sort is not
66 -- stable, i.e. the order of equal elements in the input is not preserved.