File : g-hesora.ads
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT RUN-TIME COMPONENTS --
4 -- --
5 -- G N A T . H E A P _ S O R T _ A --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 1995-2013, 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 -- --
19 -- --
20 -- --
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 -- Heapsort using access to procedure parameters
33
34 -- This package provides a heap sort routine that works with access to
35 -- subprogram parameters, so that it can be used with different types with
36 -- shared sorting code. It is considered obsoleted by GNAT.Heap_Sort which
37 -- offers a similar routine with a more convenient interface.
38
39 -- This heapsort algorithm uses approximately N*log(N) compares in the
40 -- worst case and is in place with no additional storage required. See
41 -- the body for exact details of the algorithm used.
42
43 pragma Compiler_Unit_Warning;
44
45 package GNAT.Heap_Sort_A is
46 pragma Preelaborate;
47
48 -- The data to be sorted is assumed to be indexed by integer values from
49 -- 1 to N, where N is the number of items to be sorted. In addition, the
50 -- index value zero is used for a temporary location used during the sort.
51
52 type Move_Procedure is access procedure (From : Natural; To : Natural);
53 -- A pointer to a procedure that moves the data item with index From to
54 -- the data item with index To. An index value of zero is used for moves
55 -- from and to the single temporary location used by the sort.
56
57 type Lt_Function is access function (Op1, Op2 : Natural) return Boolean;
58 -- A pointer to a function that compares two items and returns True if
59 -- the item with index Op1 is less than the item with index Op2, and False
60 -- if the Op1 item is greater than or equal to the Op2 item.
61
62 procedure Sort (N : Natural; Move : Move_Procedure; Lt : Lt_Function);
63 -- This procedures sorts items in the range from 1 to N into ascending
64 -- order making calls to Lt to do required comparisons, and Move to move
65 -- items around. Note that, as described above, both Move and Lt use a
66 -- single temporary location with index value zero. This sort is not
67 -- stable, i.e. the order of equal elements in the input is not preserved.
68
69 end GNAT.Heap_Sort_A;