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Diffstat (limited to 'gcc-4.9/gcc/ada/a-chtgke.adb')
| -rw-r--r-- | gcc-4.9/gcc/ada/a-chtgke.adb | 399 |
1 files changed, 399 insertions, 0 deletions
diff --git a/gcc-4.9/gcc/ada/a-chtgke.adb b/gcc-4.9/gcc/ada/a-chtgke.adb new file mode 100644 index 000000000..df7821d74 --- /dev/null +++ b/gcc-4.9/gcc/ada/a-chtgke.adb @@ -0,0 +1,399 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT LIBRARY COMPONENTS -- +-- -- +-- ADA.CONTAINERS.HASH_TABLES.GENERIC_KEYS -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 2004-2013, 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. -- +------------------------------------------------------------------------------ + +package body Ada.Containers.Hash_Tables.Generic_Keys is + + ----------------------------- + -- Checked_Equivalent_Keys -- + ----------------------------- + + function Checked_Equivalent_Keys + (HT : aliased in out Hash_Table_Type; + Key : Key_Type; + Node : Node_Access) return Boolean + is + Result : Boolean; + + B : Natural renames HT.Busy; + L : Natural renames HT.Lock; + + begin + B := B + 1; + L := L + 1; + + Result := Equivalent_Keys (Key, Node); + + B := B - 1; + L := L - 1; + + return Result; + + exception + when others => + B := B - 1; + L := L - 1; + + raise; + end Checked_Equivalent_Keys; + + ------------------- + -- Checked_Index -- + ------------------- + + function Checked_Index + (HT : aliased in out Hash_Table_Type; + Key : Key_Type) return Hash_Type + is + Result : Hash_Type; + + B : Natural renames HT.Busy; + L : Natural renames HT.Lock; + + begin + B := B + 1; + L := L + 1; + + Result := Hash (Key) mod HT.Buckets'Length; + + B := B - 1; + L := L - 1; + + return Result; + + exception + when others => + B := B - 1; + L := L - 1; + + raise; + end Checked_Index; + + -------------------------- + -- Delete_Key_Sans_Free -- + -------------------------- + + procedure Delete_Key_Sans_Free + (HT : in out Hash_Table_Type; + Key : Key_Type; + X : out Node_Access) + is + Indx : Hash_Type; + Prev : Node_Access; + + begin + if HT.Length = 0 then + X := null; + return; + end if; + + -- Per AI05-0022, the container implementation is required to detect + -- element tampering by a generic actual subprogram. + + if HT.Busy > 0 then + raise Program_Error with + "attempt to tamper with cursors (container is busy)"; + end if; + + Indx := Checked_Index (HT, Key); + X := HT.Buckets (Indx); + + if X = null then + return; + end if; + + if Checked_Equivalent_Keys (HT, Key, X) then + if HT.Busy > 0 then + raise Program_Error with + "attempt to tamper with cursors (container is busy)"; + end if; + HT.Buckets (Indx) := Next (X); + HT.Length := HT.Length - 1; + return; + end if; + + loop + Prev := X; + X := Next (Prev); + + if X = null then + return; + end if; + + if Checked_Equivalent_Keys (HT, Key, X) then + if HT.Busy > 0 then + raise Program_Error with + "attempt to tamper with cursors (container is busy)"; + end if; + Set_Next (Node => Prev, Next => Next (X)); + HT.Length := HT.Length - 1; + return; + end if; + end loop; + end Delete_Key_Sans_Free; + + ---------- + -- Find -- + ---------- + + function Find + (HT : aliased in out Hash_Table_Type; + Key : Key_Type) return Node_Access + is + Indx : Hash_Type; + Node : Node_Access; + + begin + if HT.Length = 0 then + return null; + end if; + + Indx := Checked_Index (HT, Key); + + Node := HT.Buckets (Indx); + while Node /= null loop + if Checked_Equivalent_Keys (HT, Key, Node) then + return Node; + end if; + Node := Next (Node); + end loop; + + return null; + end Find; + + -------------------------------- + -- Generic_Conditional_Insert -- + -------------------------------- + + procedure Generic_Conditional_Insert + (HT : in out Hash_Table_Type; + Key : Key_Type; + Node : out Node_Access; + Inserted : out Boolean) + is + Indx : Hash_Type; + + begin + -- Per AI05-0022, the container implementation is required to detect + -- element tampering by a generic actual subprogram. + + if HT.Busy > 0 then + raise Program_Error with + "attempt to tamper with cursors (container is busy)"; + end if; + + Indx := Checked_Index (HT, Key); + Node := HT.Buckets (Indx); + + if Node = null then + if HT.Length = Count_Type'Last then + raise Constraint_Error; + end if; + + Node := New_Node (Next => null); + Inserted := True; + + HT.Buckets (Indx) := Node; + HT.Length := HT.Length + 1; + + return; + end if; + + loop + if Checked_Equivalent_Keys (HT, Key, Node) then + Inserted := False; + return; + end if; + + Node := Next (Node); + + exit when Node = null; + end loop; + + if HT.Length = Count_Type'Last then + raise Constraint_Error; + end if; + + Node := New_Node (Next => HT.Buckets (Indx)); + Inserted := True; + + HT.Buckets (Indx) := Node; + HT.Length := HT.Length + 1; + end Generic_Conditional_Insert; + + ----------------------------- + -- Generic_Replace_Element -- + ----------------------------- + + procedure Generic_Replace_Element + (HT : in out Hash_Table_Type; + Node : Node_Access; + Key : Key_Type) + is + pragma Assert (HT.Length > 0); + pragma Assert (Node /= null); + + Old_Indx : Hash_Type; + New_Indx : constant Hash_Type := Checked_Index (HT, Key); + + New_Bucket : Node_Access renames HT.Buckets (New_Indx); + N, M : Node_Access; + + begin + -- Per AI05-0022, the container implementation is required to detect + -- element tampering by a generic actual subprogram. + + declare + B : Natural renames HT.Busy; + L : Natural renames HT.Lock; + + begin + B := B + 1; + L := L + 1; + + Old_Indx := Hash (Node) mod HT.Buckets'Length; + + B := B - 1; + L := L - 1; + + exception + when others => + B := B - 1; + L := L - 1; + + raise; + end; + + if Checked_Equivalent_Keys (HT, Key, Node) then + if HT.Lock > 0 then + raise Program_Error with + "attempt to tamper with elements (container is locked)"; + end if; + + -- We can change a node's key to Key (that's what Assign is for), but + -- only if Key is not already in the hash table. (In a unique-key + -- hash table as this one a key is mapped to exactly one node only.) + -- The exception is when Key is mapped to Node, in which case the + -- change is allowed. + + Assign (Node, Key); + return; + end if; + + -- Key is not equivalent to Node, so we now have to determine if it's + -- equivalent to some other node in the hash table. This is the case + -- irrespective of whether Key is in the same or a different bucket from + -- Node. + + N := New_Bucket; + while N /= null loop + if Checked_Equivalent_Keys (HT, Key, N) then + pragma Assert (N /= Node); + raise Program_Error with + "attempt to replace existing element"; + end if; + + N := Next (N); + end loop; + + -- We have determined that Key is not already in the hash table, so + -- the change is tentatively allowed. We now perform the standard + -- checks to determine whether the hash table is locked (because you + -- cannot change an element while it's in use by Query_Element or + -- Update_Element), or if the container is busy (because moving a + -- node to a different bucket would interfere with iteration). + + if Old_Indx = New_Indx then + -- The node is already in the bucket implied by Key. In this case + -- we merely change its value without moving it. + + if HT.Lock > 0 then + raise Program_Error with + "attempt to tamper with elements (container is locked)"; + end if; + + Assign (Node, Key); + return; + end if; + + -- The node is a bucket different from the bucket implied by Key + + if HT.Busy > 0 then + raise Program_Error with + "attempt to tamper with cursors (container is busy)"; + end if; + + -- Do the assignment first, before moving the node, so that if Assign + -- propagates an exception, then the hash table will not have been + -- modified (except for any possible side-effect Assign had on Node). + + Assign (Node, Key); + + -- Now we can safely remove the node from its current bucket + + N := HT.Buckets (Old_Indx); + pragma Assert (N /= null); + + if N = Node then + HT.Buckets (Old_Indx) := Next (Node); + + else + pragma Assert (HT.Length > 1); + + loop + M := Next (N); + pragma Assert (M /= null); + + if M = Node then + Set_Next (Node => N, Next => Next (Node)); + exit; + end if; + + N := M; + end loop; + end if; + + -- Now we link the node into its new bucket (corresponding to Key) + + Set_Next (Node => Node, Next => New_Bucket); + New_Bucket := Node; + end Generic_Replace_Element; + + ----------- + -- Index -- + ----------- + + function Index + (HT : Hash_Table_Type; + Key : Key_Type) return Hash_Type + is + begin + return Hash (Key) mod HT.Buckets'Length; + end Index; + +end Ada.Containers.Hash_Tables.Generic_Keys; |