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authorTristan Gingold <tgingold@free.fr>2014-11-05 05:11:00 +0100
committerTristan Gingold <tgingold@free.fr>2014-11-05 05:11:00 +0100
commit3fddf1c59fd7a8fcd260bb9e05c611bef3dd141b (patch)
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+-- GHDL Run Time (GRT) - binary balanced tree.
+-- Copyright (C) 2002 - 2014 Tristan Gingold
+--
+-- GHDL is free software; you can redistribute it and/or modify it under
+-- the terms of the GNU General Public License as published by the Free
+-- Software Foundation; either version 2, or (at your option) any later
+-- version.
+--
+-- GHDL is distributed in the hope that it will be useful, but WITHOUT 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
+-- along with GCC; see the 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.
+with Grt.Errors; use Grt.Errors;
+
+package body Grt.Avls is
+ function Get_Height (Tree: AVL_Tree; N : AVL_Nid) return Ghdl_I32 is
+ begin
+ if N = AVL_Nil then
+ return 0;
+ else
+ return Tree (N).Height;
+ end if;
+ end Get_Height;
+
+ procedure Check_AVL (Tree : AVL_Tree; N : AVL_Nid)
+ is
+ L, R : AVL_Nid;
+ Lh, Rh : Ghdl_I32;
+ H : Ghdl_I32;
+ begin
+ if N = AVL_Nil then
+ return;
+ end if;
+ L := Tree (N).Left;
+ R := Tree (N).Right;
+ H := Get_Height (Tree, N);
+ if L = AVL_Nil and R = AVL_Nil then
+ if Get_Height (Tree, N) /= 1 then
+ Internal_Error ("check_AVL(1)");
+ end if;
+ return;
+ elsif L = AVL_Nil then
+ Check_AVL (Tree, R);
+ if H /= Get_Height (Tree, R) + 1 or H > 2 then
+ Internal_Error ("check_AVL(2)");
+ end if;
+ elsif R = AVL_Nil then
+ Check_AVL (Tree, L);
+ if H /= Get_Height (Tree, L) + 1 or H > 2 then
+ Internal_Error ("check_AVL(3)");
+ end if;
+ else
+ Check_AVL (Tree, L);
+ Check_AVL (Tree, R);
+ Lh := Get_Height (Tree, L);
+ Rh := Get_Height (Tree, R);
+ if Ghdl_I32'Max (Lh, Rh) + 1 /= H then
+ Internal_Error ("check_AVL(4)");
+ end if;
+ if Rh - Lh > 1 or Rh - Lh < -1 then
+ Internal_Error ("check_AVL(5)");
+ end if;
+ end if;
+ end Check_AVL;
+
+ procedure Compute_Height (Tree : in out AVL_Tree; N : AVL_Nid)
+ is
+ begin
+ Tree (N).Height :=
+ Ghdl_I32'Max (Get_Height (Tree, Tree (N).Left),
+ Get_Height (Tree, Tree (N).Right)) + 1;
+ end Compute_Height;
+
+ procedure Simple_Rotate_Right (Tree : in out AVL_Tree; N : AVL_Nid)
+ is
+ R : AVL_Nid;
+ V : AVL_Value;
+ begin
+ -- Rotate nodes.
+ R := Tree (N).Right;
+ Tree (N).Right := Tree (R).Right;
+ Tree (R).Right := Tree (R).Left;
+ Tree (R).Left := Tree (N).Left;
+ Tree (N).Left := R;
+ -- Swap vals.
+ V := Tree (N).Val;
+ Tree (N).Val := Tree (R).Val;
+ Tree (R).Val := V;
+ -- Adjust bal.
+ Compute_Height (Tree, R);
+ Compute_Height (Tree, N);
+ end Simple_Rotate_Right;
+
+ procedure Simple_Rotate_Left (Tree : in out AVL_Tree; N : AVL_Nid)
+ is
+ L : AVL_Nid;
+ V : AVL_Value;
+ begin
+ L := Tree (N).Left;
+ Tree (N).Left := Tree (L).Left;
+ Tree (L).Left := Tree (L).Right;
+ Tree (L).Right := Tree (N).Right;
+ Tree (N).Right := L;
+ V := Tree (N).Val;
+ Tree (N).Val := Tree (L).Val;
+ Tree (L).Val := V;
+ Compute_Height (Tree, L);
+ Compute_Height (Tree, N);
+ end Simple_Rotate_Left;
+
+ procedure Double_Rotate_Right (Tree : in out AVL_Tree; N : AVL_Nid)
+ is
+ R : AVL_Nid;
+ begin
+ R := Tree (N).Right;
+ Simple_Rotate_Left (Tree, R);
+ Simple_Rotate_Right (Tree, N);
+ end Double_Rotate_Right;
+
+ procedure Double_Rotate_Left (Tree : in out AVL_Tree; N : AVL_Nid)
+ is
+ L : AVL_Nid;
+ begin
+ L := Tree (N).Left;
+ Simple_Rotate_Right (Tree, L);
+ Simple_Rotate_Left (Tree, N);
+ end Double_Rotate_Left;
+
+ procedure Insert (Tree : in out AVL_Tree;
+ Cmp : AVL_Compare_Func;
+ Val : AVL_Nid;
+ N : AVL_Nid;
+ Res : out AVL_Nid)
+ is
+ Diff : Integer;
+ Op_Ch, Ch : AVL_Nid;
+ begin
+ Diff := Cmp.all (Tree (Val).Val, Tree (N).Val);
+ if Diff = 0 then
+ Res := N;
+ return;
+ end if;
+ if Diff < 0 then
+ if Tree (N).Left = AVL_Nil then
+ Tree (N).Left := Val;
+ Compute_Height (Tree, N);
+ -- N is balanced.
+ Res := Val;
+ else
+ Ch := Tree (N).Left;
+ Op_Ch := Tree (N).Right;
+ Insert (Tree, Cmp, Val, Ch, Res);
+ if Res /= Val then
+ return;
+ end if;
+ if Get_Height (Tree, Ch) - Get_Height (Tree, Op_Ch) = 2 then
+ -- Rotate
+ if Get_Height (Tree, Tree (Ch).Left)
+ > Get_Height (Tree, Tree (Ch).Right)
+ then
+ Simple_Rotate_Left (Tree, N);
+ else
+ Double_Rotate_Left (Tree, N);
+ end if;
+ else
+ Compute_Height (Tree, N);
+ end if;
+ end if;
+ else
+ if Tree (N).Right = AVL_Nil then
+ Tree (N).Right := Val;
+ Compute_Height (Tree, N);
+ -- N is balanced.
+ Res := Val;
+ else
+ Ch := Tree (N).Right;
+ Op_Ch := Tree (N).Left;
+ Insert (Tree, Cmp, Val, Ch, Res);
+ if Res /= Val then
+ return;
+ end if;
+ if Get_Height (Tree, Ch) - Get_Height (Tree, Op_Ch) = 2 then
+ -- Rotate
+ if Get_Height (Tree, Tree (Ch).Right)
+ > Get_Height (Tree, Tree (Ch).Left)
+ then
+ Simple_Rotate_Right (Tree, N);
+ else
+ Double_Rotate_Right (Tree, N);
+ end if;
+ else
+ Compute_Height (Tree, N);
+ end if;
+ end if;
+ end if;
+ end Insert;
+
+ procedure Get_Node (Tree : in out AVL_Tree;
+ Cmp : AVL_Compare_Func;
+ N : AVL_Nid;
+ Res : out AVL_Nid)
+ is
+ begin
+ if Tree'First /= AVL_Root or N /= Tree'Last then
+ Internal_Error ("avls.get_node");
+ end if;
+ Insert (Tree, Cmp, N, AVL_Root, Res);
+ Check_AVL (Tree, AVL_Root);
+ end Get_Node;
+
+ function Find_Node (Tree : AVL_Tree;
+ Cmp : AVL_Compare_Func;
+ Val : AVL_Value) return AVL_Nid
+ is
+ N : AVL_Nid;
+ Diff : Integer;
+ begin
+ N := AVL_Root;
+ if Tree'Last < AVL_Root then
+ return AVL_Nil;
+ end if;
+ loop
+ Diff := Cmp.all (Val, Tree (N).Val);
+ if Diff = 0 then
+ return N;
+ end if;
+ if Diff < 0 then
+ N := Tree (N).Left;
+ else
+ N := Tree (N).Right;
+ end if;
+ if N = AVL_Nil then
+ return AVL_Nil;
+ end if;
+ end loop;
+ end Find_Node;
+end Grt.Avls;