------------------------------------------------------------------------------ -- -- -- GNAT RUNTIME COMPONENTS -- -- -- -- G N A T . H E A P _ S O R T _ A -- -- -- -- S p e c -- -- -- -- Copyright (C) 1995-2002 Ada Core Technologies, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 2, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING. If not, write -- -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- As a special exception, if other files instantiate generics from this -- -- unit, or you link this unit with other files to produce an executable, -- -- this unit does not by itself cause the resulting executable to be -- -- covered by the GNU General Public License. This exception does not -- -- however invalidate any other reasons why the executable file might be -- -- covered by the GNU Public License. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ -- Heapsort using access to procedure parameters -- This package provides a heap sort routine that works with access to -- subprogram parameters, so that it can be used with different types with -- shared sorting code. It is considered obsoleted by GNAT.Heap_Sort which -- offers a similar routine with a more convenient interface. -- This heapsort algorithm uses approximately N*log(N) compares in the -- worst case and is in place with no additional storage required. See -- the body for exact details of the algorithm used. package GNAT.Heap_Sort_A is pragma Preelaborate (Heap_Sort_A); -- The data to be sorted is assumed to be indexed by integer values from -- 1 to N, where N is the number of items to be sorted. In addition, the -- index value zero is used for a temporary location used during the sort. type Move_Procedure is access procedure (From : Natural; To : Natural); -- A pointer to a procedure that moves the data item with index From to -- the data item with index To. An index value of zero is used for moves -- from and to the single temporary location used by the sort. type Lt_Function is access function (Op1, Op2 : Natural) return Boolean; -- A pointer to a function that compares two items and returns True if -- the item with index Op1 is less than the item with index Op2, and False -- if the Op1 item is greater than or equal to the Op2 item. procedure Sort (N : Natural; Move : Move_Procedure; Lt : Lt_Function); -- This procedures sorts items in the range from 1 to N into ascending -- order making calls to Lt to do required comparisons, and Move to move -- items around. Note that, as described above, both Move and Lt use a -- single temporary location with index value zero. This sort is not -- stable, i.e. the order of equal elements in the input is not preserved. end GNAT.Heap_Sort_A;