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Diffstat (limited to 'gcc-4.3.1/gcc/ada/a-crbtgk.adb')
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diff --git a/gcc-4.3.1/gcc/ada/a-crbtgk.adb b/gcc-4.3.1/gcc/ada/a-crbtgk.adb new file mode 100644 index 000000000..f90568d33 --- /dev/null +++ b/gcc-4.3.1/gcc/ada/a-crbtgk.adb @@ -0,0 +1,576 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT LIBRARY COMPONENTS -- +-- -- +-- A D A . C O N T A I N E R S . R E D _ B L A C K _ T R E E S . -- +-- G E N E R I C _ K E Y S -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 2004-2006, 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 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, 51 Franklin Street, Fifth Floor, -- +-- Boston, MA 02110-1301, 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. -- +------------------------------------------------------------------------------ + +package body Ada.Containers.Red_Black_Trees.Generic_Keys is + + package Ops renames Tree_Operations; + + ------------- + -- Ceiling -- + ------------- + + -- AKA Lower_Bound + + function Ceiling (Tree : Tree_Type; Key : Key_Type) return Node_Access is + Y : Node_Access; + X : Node_Access; + + begin + X := Tree.Root; + while X /= null loop + if Is_Greater_Key_Node (Key, X) then + X := Ops.Right (X); + else + Y := X; + X := Ops.Left (X); + end if; + end loop; + + return Y; + end Ceiling; + + ---------- + -- Find -- + ---------- + + function Find (Tree : Tree_Type; Key : Key_Type) return Node_Access is + Y : Node_Access; + X : Node_Access; + + begin + X := Tree.Root; + while X /= null loop + if Is_Greater_Key_Node (Key, X) then + X := Ops.Right (X); + else + Y := X; + X := Ops.Left (X); + end if; + end loop; + + if Y = null then + return null; + end if; + + if Is_Less_Key_Node (Key, Y) then + return null; + end if; + + return Y; + end Find; + + ----------- + -- Floor -- + ----------- + + function Floor (Tree : Tree_Type; Key : Key_Type) return Node_Access is + Y : Node_Access; + X : Node_Access; + + begin + X := Tree.Root; + while X /= null loop + if Is_Less_Key_Node (Key, X) then + X := Ops.Left (X); + else + Y := X; + X := Ops.Right (X); + end if; + end loop; + + return Y; + end Floor; + + -------------------------------- + -- Generic_Conditional_Insert -- + -------------------------------- + + procedure Generic_Conditional_Insert + (Tree : in out Tree_Type; + Key : Key_Type; + Node : out Node_Access; + Inserted : out Boolean) + is + Y : Node_Access := null; + X : Node_Access := Tree.Root; + + begin + Inserted := True; + while X /= null loop + Y := X; + Inserted := Is_Less_Key_Node (Key, X); + + if Inserted then + X := Ops.Left (X); + else + X := Ops.Right (X); + end if; + end loop; + + -- If Inserted is True, then this means either that Tree is + -- empty, or there was a least one node (strictly) greater than + -- Key. Otherwise, it means that Key is equal to or greater than + -- every node. + + if Inserted then + if Y = Tree.First then + Insert_Post (Tree, Y, True, Node); + return; + end if; + + Node := Ops.Previous (Y); + + else + Node := Y; + end if; + + -- Here Node has a value that is less than or equal to Key. We + -- now have to resolve whether Key is equal to or greater than + -- Node, which determines whether the insertion succeeds. + + if Is_Greater_Key_Node (Key, Node) then + Insert_Post (Tree, Y, Inserted, Node); + Inserted := True; + return; + end if; + + Inserted := False; + end Generic_Conditional_Insert; + + ------------------------------------------ + -- Generic_Conditional_Insert_With_Hint -- + ------------------------------------------ + + procedure Generic_Conditional_Insert_With_Hint + (Tree : in out Tree_Type; + Position : Node_Access; + Key : Key_Type; + Node : out Node_Access; + Inserted : out Boolean) + is + begin + -- The purpose of a hint is to avoid a search from the root of + -- tree. If we have it hint it means we only need to traverse the + -- subtree rooted at the hint to find the nearest neighbor. Note + -- that finding the neighbor means merely walking the tree; this + -- is not a search and the only comparisons that occur are with + -- the hint and its neighbor. + + -- If Position is null, this is intepreted to mean that Key is + -- large relative to the nodes in the tree. If the tree is empty, + -- or Key is greater than the last node in the tree, then we're + -- done; otherwise the hint was "wrong" and we must search. + + if Position = null then -- largest + if Tree.Last = null + or else Is_Greater_Key_Node (Key, Tree.Last) + then + Insert_Post (Tree, Tree.Last, False, Node); + Inserted := True; + else + Conditional_Insert_Sans_Hint (Tree, Key, Node, Inserted); + end if; + + return; + end if; + + pragma Assert (Tree.Length > 0); + + -- A hint can either name the node that immediately follows Key, + -- or immediately precedes Key. We first test whether Key is is + -- less than the hint, and if so we compare Key to the node that + -- precedes the hint. If Key is both less than the hint and + -- greater than the hint's preceding neighbor, then we're done; + -- otherwise we must search. + + -- Note also that a hint can either be an anterior node or a leaf + -- node. A new node is always inserted at the bottom of the tree + -- (at least prior to rebalancing), becoming the new left or + -- right child of leaf node (which prior to the insertion must + -- necessarily be null, since this is a leaf). If the hint names + -- an anterior node then its neighbor must be a leaf, and so + -- (here) we insert after the neighbor. If the hint names a leaf + -- then its neighbor must be anterior and so we insert before the + -- hint. + + if Is_Less_Key_Node (Key, Position) then + declare + Before : constant Node_Access := Ops.Previous (Position); + + begin + if Before = null then + Insert_Post (Tree, Tree.First, True, Node); + Inserted := True; + + elsif Is_Greater_Key_Node (Key, Before) then + if Ops.Right (Before) = null then + Insert_Post (Tree, Before, False, Node); + else + Insert_Post (Tree, Position, True, Node); + end if; + + Inserted := True; + + else + Conditional_Insert_Sans_Hint (Tree, Key, Node, Inserted); + end if; + end; + + return; + end if; + + -- We know that Key isn't less than the hint so we try again, + -- this time to see if it's greater than the hint. If so we + -- compare Key to the node that follows the hint. If Key is both + -- greater than the hint and less than the hint's next neighbor, + -- then we're done; otherwise we must search. + + if Is_Greater_Key_Node (Key, Position) then + declare + After : constant Node_Access := Ops.Next (Position); + + begin + if After = null then + Insert_Post (Tree, Tree.Last, False, Node); + Inserted := True; + + elsif Is_Less_Key_Node (Key, After) then + if Ops.Right (Position) = null then + Insert_Post (Tree, Position, False, Node); + else + Insert_Post (Tree, After, True, Node); + end if; + + Inserted := True; + + else + Conditional_Insert_Sans_Hint (Tree, Key, Node, Inserted); + end if; + end; + + return; + end if; + + -- We know that Key is neither less than the hint nor greater + -- than the hint, and that's the definition of equivalence. + -- There's nothing else we need to do, since a search would just + -- reach the same conclusion. + + Node := Position; + Inserted := False; + end Generic_Conditional_Insert_With_Hint; + + ------------------------- + -- Generic_Insert_Post -- + ------------------------- + + procedure Generic_Insert_Post + (Tree : in out Tree_Type; + Y : Node_Access; + Before : Boolean; + Z : out Node_Access) + is + begin + if Tree.Length = Count_Type'Last then + raise Constraint_Error with "too many elements"; + end if; + + if Tree.Busy > 0 then + raise Program_Error with + "attempt to tamper with cursors (container is busy)"; + end if; + + Z := New_Node; + pragma Assert (Z /= null); + pragma Assert (Ops.Color (Z) = Red); + + if Y = null then + pragma Assert (Tree.Length = 0); + pragma Assert (Tree.Root = null); + pragma Assert (Tree.First = null); + pragma Assert (Tree.Last = null); + + Tree.Root := Z; + Tree.First := Z; + Tree.Last := Z; + + elsif Before then + pragma Assert (Ops.Left (Y) = null); + + Ops.Set_Left (Y, Z); + + if Y = Tree.First then + Tree.First := Z; + end if; + + else + pragma Assert (Ops.Right (Y) = null); + + Ops.Set_Right (Y, Z); + + if Y = Tree.Last then + Tree.Last := Z; + end if; + end if; + + Ops.Set_Parent (Z, Y); + Ops.Rebalance_For_Insert (Tree, Z); + Tree.Length := Tree.Length + 1; + end Generic_Insert_Post; + + ----------------------- + -- Generic_Iteration -- + ----------------------- + + procedure Generic_Iteration + (Tree : Tree_Type; + Key : Key_Type) + is + procedure Iterate (Node : Node_Access); + + ------------- + -- Iterate -- + ------------- + + procedure Iterate (Node : Node_Access) is + N : Node_Access; + begin + N := Node; + while N /= null loop + if Is_Less_Key_Node (Key, N) then + N := Ops.Left (N); + elsif Is_Greater_Key_Node (Key, N) then + N := Ops.Right (N); + else + Iterate (Ops.Left (N)); + Process (N); + N := Ops.Right (N); + end if; + end loop; + end Iterate; + + -- Start of processing for Generic_Iteration + + begin + Iterate (Tree.Root); + end Generic_Iteration; + + ------------------------------- + -- Generic_Reverse_Iteration -- + ------------------------------- + + procedure Generic_Reverse_Iteration + (Tree : Tree_Type; + Key : Key_Type) + is + procedure Iterate (Node : Node_Access); + + ------------- + -- Iterate -- + ------------- + + procedure Iterate (Node : Node_Access) is + N : Node_Access; + begin + N := Node; + while N /= null loop + if Is_Less_Key_Node (Key, N) then + N := Ops.Left (N); + elsif Is_Greater_Key_Node (Key, N) then + N := Ops.Right (N); + else + Iterate (Ops.Right (N)); + Process (N); + N := Ops.Left (N); + end if; + end loop; + end Iterate; + + -- Start of processing for Generic_Reverse_Iteration + + begin + Iterate (Tree.Root); + end Generic_Reverse_Iteration; + + ---------------------------------- + -- Generic_Unconditional_Insert -- + ---------------------------------- + + procedure Generic_Unconditional_Insert + (Tree : in out Tree_Type; + Key : Key_Type; + Node : out Node_Access) + is + Y : Node_Access; + X : Node_Access; + + Before : Boolean; + + begin + Y := null; + Before := False; + + X := Tree.Root; + while X /= null loop + Y := X; + Before := Is_Less_Key_Node (Key, X); + + if Before then + X := Ops.Left (X); + else + X := Ops.Right (X); + end if; + end loop; + + Insert_Post (Tree, Y, Before, Node); + end Generic_Unconditional_Insert; + + -------------------------------------------- + -- Generic_Unconditional_Insert_With_Hint -- + -------------------------------------------- + + procedure Generic_Unconditional_Insert_With_Hint + (Tree : in out Tree_Type; + Hint : Node_Access; + Key : Key_Type; + Node : out Node_Access) + is + begin + -- There are fewer constraints for an unconditional insertion + -- than for a conditional insertion, since we allow duplicate + -- keys. So instead of having to check (say) whether Key is + -- (strictly) greater than the hint's previous neighbor, here we + -- allow Key to be equal to or greater than the previous node. + + -- There is the issue of what to do if Key is equivalent to the + -- hint. Does the new node get inserted before or after the hint? + -- We decide that it gets inserted after the hint, reasoning that + -- this is consistent with behavior for non-hint insertion, which + -- inserts a new node after existing nodes with equivalent keys. + + -- First we check whether the hint is null, which is interpreted + -- to mean that Key is large relative to existing nodes. + -- Following our rule above, if Key is equal to or greater than + -- the last node, then we insert the new node immediately after + -- last. (We don't have an operation for testing whether a key is + -- "equal to or greater than" a node, so we must say instead "not + -- less than", which is equivalent.) + + if Hint = null then -- largest + if Tree.Last = null then + Insert_Post (Tree, null, False, Node); + elsif Is_Less_Key_Node (Key, Tree.Last) then + Unconditional_Insert_Sans_Hint (Tree, Key, Node); + else + Insert_Post (Tree, Tree.Last, False, Node); + end if; + + return; + end if; + + pragma Assert (Tree.Length > 0); + + -- We decide here whether to insert the new node prior to the + -- hint. Key could be equivalent to the hint, so in theory we + -- could write the following test as "not greater than" (same as + -- "less than or equal to"). If Key were equivalent to the hint, + -- that would mean that the new node gets inserted before an + -- equivalent node. That wouldn't break any container invariants, + -- but our rule above says that new nodes always get inserted + -- after equivalent nodes. So here we test whether Key is both + -- less than the hint and and equal to or greater than the hint's + -- previous neighbor, and if so insert it before the hint. + + if Is_Less_Key_Node (Key, Hint) then + declare + Before : constant Node_Access := Ops.Previous (Hint); + begin + if Before = null then + Insert_Post (Tree, Hint, True, Node); + elsif Is_Less_Key_Node (Key, Before) then + Unconditional_Insert_Sans_Hint (Tree, Key, Node); + elsif Ops.Right (Before) = null then + Insert_Post (Tree, Before, False, Node); + else + Insert_Post (Tree, Hint, True, Node); + end if; + end; + + return; + end if; + + -- We know that Key isn't less than the hint, so it must be equal + -- or greater. So we just test whether Key is less than or equal + -- to (same as "not greater than") the hint's next neighbor, and + -- if so insert it after the hint. + + declare + After : constant Node_Access := Ops.Next (Hint); + begin + if After = null then + Insert_Post (Tree, Hint, False, Node); + elsif Is_Greater_Key_Node (Key, After) then + Unconditional_Insert_Sans_Hint (Tree, Key, Node); + elsif Ops.Right (Hint) = null then + Insert_Post (Tree, Hint, False, Node); + else + Insert_Post (Tree, After, True, Node); + end if; + end; + end Generic_Unconditional_Insert_With_Hint; + + ----------------- + -- Upper_Bound -- + ----------------- + + function Upper_Bound + (Tree : Tree_Type; + Key : Key_Type) return Node_Access + is + Y : Node_Access; + X : Node_Access; + + begin + X := Tree.Root; + while X /= null loop + if Is_Less_Key_Node (Key, X) then + Y := X; + X := Ops.Left (X); + else + X := Ops.Right (X); + end if; + end loop; + + return Y; + end Upper_Bound; + +end Ada.Containers.Red_Black_Trees.Generic_Keys; |