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Diffstat (limited to 'gcc/ada/a-cogeso.adb')
| -rw-r--r-- | gcc/ada/a-cogeso.adb | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/gcc/ada/a-cogeso.adb b/gcc/ada/a-cogeso.adb new file mode 100644 index 00000000000..fc2198cb4b1 --- /dev/null +++ b/gcc/ada/a-cogeso.adb @@ -0,0 +1,127 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT LIBRARY COMPONENTS -- +-- -- +-- ADA.CONTAINERS.GENERIC_SORT -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 2011, Free Software Foundation, 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 3, 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. -- +-- -- +-- As a special exception under Section 7 of GPL version 3, you are granted -- +-- additional permissions described in the GCC Runtime Library Exception, -- +-- version 3.1, as published by the Free Software Foundation. -- +-- -- +-- You should have received a copy of the GNU General Public License and -- +-- a copy of the GCC Runtime Library Exception along with this program; -- +-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- +-- <http://www.gnu.org/licenses/>. -- +-- -- +-- This unit was originally developed by Matthew J Heaney. -- +------------------------------------------------------------------------------ + +-- This algorithm was adapted from GNAT.Heap_Sort (see g-heasor.ad[sb]) + +with System; + +procedure Ada.Containers.Generic_Sort (First, Last : Index_Type'Base) is + type T is range System.Min_Int .. System.Max_Int; + + function To_Index (J : T) return Index_Type; + pragma Inline (To_Index); + + function Lt (J, K : T) return Boolean; + pragma Inline (Lt); + + procedure Xchg (J, K : T); + pragma Inline (Xchg); + + procedure Sift (S : T); + + -------------- + -- To_Index -- + -------------- + + function To_Index (J : T) return Index_Type is + K : constant T'Base := Index_Type'Pos (First) + J - T'(1); + begin + return Index_Type'Val (K); + end To_Index; + + -------- + -- Lt -- + -------- + + function Lt (J, K : T) return Boolean is + begin + return Before (To_Index (J), To_Index (K)); + end Lt; + + ---------- + -- Xchg -- + ---------- + + procedure Xchg (J, K : T) is + begin + Swap (To_Index (J), To_Index (K)); + end Xchg; + + Max : T := Index_Type'Pos (Last) - Index_Type'Pos (First) + T'(1); + + ---------- + -- Sift -- + ---------- + + procedure Sift (S : T) is + C : T := S; + Son : T; + Father : T; + + begin + loop + Son := C + C; + + if Son < Max then + if Lt (Son, Son + 1) then + Son := Son + 1; + end if; + elsif Son > Max then + exit; + end if; + + Xchg (Son, C); + C := Son; + end loop; + + while C /= S loop + Father := C / 2; + + if Lt (Father, C) then + Xchg (Father, C); + C := Father; + else + exit; + end if; + end loop; + end Sift; + +-- Start of processing for Generic_Sort + +begin + for J in reverse 1 .. Max / 2 loop + Sift (J); + end loop; + + while Max > 1 loop + Xchg (1, Max); + Max := Max - 1; + Sift (1); + end loop; +end Ada.Containers.Generic_Sort; |