| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT LIBRARY COMPONENTS -- |
| -- -- |
| -- ADA.CONTAINERS.GENERIC_ANONYMOUS_ARRAY_SORT -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- Copyright (C) 2004 Free Software Foundation, Inc. -- |
| -- -- |
| -- This specification is derived from the Ada Reference Manual for use with -- |
| -- GNAT. The copyright notice above, and the license provisions that follow -- |
| -- apply solely to the contents of the part following the private keyword. -- |
| -- -- |
| -- 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. -- |
| -- -- |
| -- This unit was originally developed by Matthew J Heaney. -- |
| ------------------------------------------------------------------------------ |
| |
| procedure Ada.Containers.Generic_Anonymous_Array_Sort |
| (First, Last : Index_Type'Base) |
| is |
| Pivot, Lo, Mid, Hi : Index_Type; |
| |
| begin |
| if Last <= First then |
| return; |
| end if; |
| |
| Lo := First; |
| Hi := Last; |
| |
| if Last = Index_Type'Succ (First) then |
| if not Less (Lo, Hi) then |
| Swap (Lo, Hi); |
| end if; |
| |
| return; |
| end if; |
| |
| Mid := Index_Type'Val |
| (Index_Type'Pos (Lo) + |
| (Index_Type'Pos (Hi) - Index_Type'Pos (Lo)) / 2); |
| |
| -- We need to figure out which case we have: |
| -- x < y < z |
| -- x < z < y |
| -- z < x < y |
| -- y < x < z |
| -- y < z < x |
| -- z < y < x |
| |
| if Less (Lo, Mid) then |
| if Less (Lo, Hi) then |
| if Less (Mid, Hi) then |
| Swap (Lo, Mid); |
| |
| else |
| Swap (Lo, Hi); |
| |
| end if; |
| |
| else |
| null; -- lo is median |
| end if; |
| |
| elsif Less (Lo, Hi) then |
| null; -- lo is median |
| |
| elsif Less (Mid, Hi) then |
| Swap (Lo, Hi); |
| |
| else |
| Swap (Lo, Mid); |
| end if; |
| |
| Pivot := Lo; |
| Outer : loop |
| loop |
| exit Outer when not (Pivot < Hi); |
| |
| if Less (Hi, Pivot) then |
| Swap (Hi, Pivot); |
| Pivot := Hi; |
| Lo := Index_Type'Succ (Lo); |
| exit; |
| else |
| Hi := Index_Type'Pred (Hi); |
| end if; |
| end loop; |
| |
| loop |
| exit Outer when not (Lo < Pivot); |
| |
| if Less (Lo, Pivot) then |
| Lo := Index_Type'Succ (Lo); |
| else |
| Swap (Lo, Pivot); |
| Pivot := Lo; |
| Hi := Index_Type'Pred (Hi); |
| exit; |
| end if; |
| end loop; |
| end loop Outer; |
| |
| Generic_Anonymous_Array_Sort (First, Index_Type'Pred (Pivot)); |
| Generic_Anonymous_Array_Sort (Index_Type'Succ (Pivot), Last); |
| |
| end Ada.Containers.Generic_Anonymous_Array_Sort; |
