1------------------------------------------------------------------------------ 2-- -- 3-- GNAT LIBRARY COMPONENTS -- 4-- -- 5-- ADA.CONTAINERS.GENERIC_SORT -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 2011-2021, Free Software Foundation, Inc. -- 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-- This unit was originally developed by Matthew J Heaney. -- 28------------------------------------------------------------------------------ 29 30-- This algorithm was adapted from GNAT.Heap_Sort (see g-heasor.ad[sb]) 31 32procedure Ada.Containers.Generic_Sort (First, Last : Index_Type'Base) is 33 subtype T is Long_Long_Integer; 34 35 function To_Index (J : T) return Index_Type; 36 pragma Inline (To_Index); 37 38 function Lt (J, K : T) return Boolean; 39 pragma Inline (Lt); 40 41 procedure Xchg (J, K : T); 42 pragma Inline (Xchg); 43 44 procedure Sift (S : T); 45 46 -------------- 47 -- To_Index -- 48 -------------- 49 50 function To_Index (J : T) return Index_Type is 51 K : constant T'Base := Index_Type'Pos (First) + J - T'(1); 52 begin 53 return Index_Type'Val (K); 54 end To_Index; 55 56 -------- 57 -- Lt -- 58 -------- 59 60 function Lt (J, K : T) return Boolean is 61 begin 62 return Before (To_Index (J), To_Index (K)); 63 end Lt; 64 65 ---------- 66 -- Xchg -- 67 ---------- 68 69 procedure Xchg (J, K : T) is 70 begin 71 Swap (To_Index (J), To_Index (K)); 72 end Xchg; 73 74 Max : T := Index_Type'Pos (Last) - Index_Type'Pos (First) + T'(1); 75 76 ---------- 77 -- Sift -- 78 ---------- 79 80 procedure Sift (S : T) is 81 C : T := S; 82 Son : T; 83 Father : T; 84 85 begin 86 loop 87 Son := C + C; 88 89 if Son < Max then 90 if Lt (Son, Son + 1) then 91 Son := Son + 1; 92 end if; 93 elsif Son > Max then 94 exit; 95 end if; 96 97 Xchg (Son, C); 98 C := Son; 99 end loop; 100 101 while C /= S loop 102 Father := C / 2; 103 104 if Lt (Father, C) then 105 Xchg (Father, C); 106 C := Father; 107 else 108 exit; 109 end if; 110 end loop; 111 end Sift; 112 113-- Start of processing for Generic_Sort 114 115begin 116 for J in reverse 1 .. Max / 2 loop 117 Sift (J); 118 end loop; 119 120 while Max > 1 loop 121 Xchg (1, Max); 122 Max := Max - 1; 123 Sift (1); 124 end loop; 125end Ada.Containers.Generic_Sort; 126