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Diffstat (limited to 'gcc/ada/g-hesora.adb')
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1 files changed, 0 insertions, 134 deletions
diff --git a/gcc/ada/g-hesora.adb b/gcc/ada/g-hesora.adb deleted file mode 100644 index cf7202da324..00000000000 --- a/gcc/ada/g-hesora.adb +++ /dev/null @@ -1,134 +0,0 @@ ------------------------------------------------------------------------------- --- -- --- GNAT RUN-TIME COMPONENTS -- --- -- --- G N A T . H E A P _ S O R T _ A -- --- -- --- B o d y -- --- -- --- Copyright (C) 1995-2013, AdaCore -- --- -- --- 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/>. -- --- -- --- GNAT was originally developed by the GNAT team at New York University. -- --- Extensive contributions were provided by Ada Core Technologies Inc. -- --- -- ------------------------------------------------------------------------------- - -pragma Compiler_Unit_Warning; - -package body GNAT.Heap_Sort_A is - - ---------- - -- Sort -- - ---------- - - -- We are using the classical heapsort algorithm (i.e. Floyd's Treesort3) - -- as described by Knuth ("The Art of Programming", Volume III, first - -- edition, section 5.2.3, p. 145-147) with the modification that is - -- mentioned in exercise 18. For more details on this algorithm, see - -- Robert B. K. Dewar PhD thesis "The use of Computers in the X-ray - -- Phase Problem". University of Chicago, 1968, which was the first - -- publication of the modification, which reduces the number of compares - -- from 2NlogN to NlogN. - - procedure Sort (N : Natural; Move : Move_Procedure; Lt : Lt_Function) is - - Max : Natural := N; - -- Current Max index in tree being sifted - - procedure Sift (S : Positive); - -- This procedure sifts up node S, i.e. converts the subtree rooted - -- at node S into a heap, given the precondition that any sons of - -- S are already heaps. On entry, the contents of node S is found - -- in the temporary (index 0), the actual contents of node S on - -- entry are irrelevant. This is just a minor optimization to avoid - -- what would otherwise be two junk moves in phase two of the sort. - - procedure Sift (S : Positive) is - C : Positive := S; - Son : Positive; - Father : Positive; - - begin - -- This is where the optimization is done, normally we would do a - -- comparison at each stage between the current node and the larger - -- of the two sons, and continue the sift only if the current node - -- was less than this maximum. In this modified optimized version, - -- we assume that the current node will be less than the larger - -- son, and unconditionally sift up. Then when we get to the bottom - -- of the tree, we check parents to make sure that we did not make - -- a mistake. This roughly cuts the number of comparisons in half, - -- since it is almost always the case that our assumption is correct. - - -- Loop to pull up larger sons - - loop - Son := 2 * C; - exit when Son > Max; - - if Son < Max and then Lt (Son, Son + 1) then - Son := Son + 1; - end if; - - Move (Son, C); - C := Son; - end loop; - - -- Loop to check fathers - - while C /= S loop - Father := C / 2; - - if Lt (Father, 0) then - Move (Father, C); - C := Father; - else - exit; - end if; - end loop; - - -- Last step is to pop the sifted node into place - - Move (0, C); - end Sift; - - -- Start of processing for Sort - - begin - -- Phase one of heapsort is to build the heap. This is done by - -- sifting nodes N/2 .. 1 in sequence. - - for J in reverse 1 .. N / 2 loop - Move (J, 0); - Sift (J); - end loop; - - -- In phase 2, the largest node is moved to end, reducing the size - -- of the tree by one, and the displaced node is sifted down from - -- the top, so that the largest node is again at the top. - - while Max > 1 loop - Move (Max, 0); - Move (1, Max); - Max := Max - 1; - Sift (1); - end loop; - - end Sort; - -end GNAT.Heap_Sort_A; |