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+++ b/gcc/ada/libgnat/g-dynhta.ads	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,266 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                         GNAT RUN-TIME COMPONENTS                         --
+--                                                                          --
+--                 G N A T . D Y N A M I C _ H T A B L E S                  --
+--                                                                          --
+--                                 S p e c                                  --
+--                                                                          --
+--                     Copyright (C) 1995-2017, 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.      --
+--                                                                          --
+------------------------------------------------------------------------------
+
+--  Hash table searching routines
+
+--  This package contains three separate packages. The Simple_HTable package
+--  provides a very simple abstraction that associates one element to one key
+--  value and takes care of all allocations automatically using the heap. The
+--  Static_HTable package provides a more complex interface that allows full
+--  control over allocation. The Load_Factor_HTable package provides a more
+--  complex abstraction where collisions are resolved by chaining, and the
+--  table grows by a percentage after the load factor has been exceeded.
+
+--  This package provides a facility similar to that of GNAT.HTable, except
+--  that this package declares types that can be used to define dynamic
+--  instances of hash tables, while instantiations in GNAT.HTable creates a
+--  single instance of the hash table.
+
+--  Note that this interface should remain synchronized with those in
+--  GNAT.HTable to keep as much coherency as possible between these two
+--  related units.
+
+package GNAT.Dynamic_HTables is
+
+   -------------------
+   -- Static_HTable --
+   -------------------
+
+   --  A low-level Hash-Table abstraction, not as easy to instantiate as
+   --  Simple_HTable. This mirrors the interface of GNAT.HTable.Static_HTable,
+   --  but does require dynamic allocation (since we allow multiple instances
+   --  of the table). The model is that each Element contains its own Key that
+   --  can be retrieved by Get_Key. Furthermore, Element provides a link that
+   --  can be used by the HTable for linking elements with same hash codes:
+
+   --       Element
+
+   --         +-------------------+
+   --         |       Key         |
+   --         +-------------------+
+   --         :    other data     :
+   --         +-------------------+
+   --         |     Next Elmt     |
+   --         +-------------------+
+
+   generic
+      type Header_Num is range <>;
+      --  An integer type indicating the number and range of hash headers
+
+      type Element (<>) is limited private;
+      --  The type of element to be stored
+
+      type Elmt_Ptr is private;
+      --  The type used to reference an element (will usually be an access
+      --  type, but could be some other form of type such as an integer type).
+
+      Null_Ptr : Elmt_Ptr;
+      --  The null value of the Elmt_Ptr type
+
+      with procedure Set_Next (E : Elmt_Ptr; Next : Elmt_Ptr);
+      with function  Next     (E : Elmt_Ptr) return Elmt_Ptr;
+      --  The type must provide an internal link for the sake of the
+      --  staticness of the HTable.
+
+      type Key is limited private;
+      with function Get_Key (E : Elmt_Ptr) return Key;
+      with function Hash    (F : Key)      return Header_Num;
+      with function Equal   (F1, F2 : Key) return Boolean;
+
+   package Static_HTable is
+
+      type Instance is private;
+      Nil : constant Instance;
+
+      procedure Reset (T : in out Instance);
+      --  Resets the hash table by releasing all memory associated with
+      --  it. The hash table can safely be reused after this call. For the
+      --  most common case where Elmt_Ptr is an access type, and Null_Ptr is
+      --  null, this is only needed if the same table is reused in a new
+      --  context. If Elmt_Ptr is other than an access type, or Null_Ptr is
+      --  other than null, then Reset must be called before the first use of
+      --  the hash table.
+
+      procedure Set (T : in out Instance; E : Elmt_Ptr);
+      --  Insert the element pointer in the HTable
+
+      function Get (T : Instance; K : Key) return Elmt_Ptr;
+      --  Returns the latest inserted element pointer with the given Key
+      --  or null if none.
+
+      procedure Remove (T : Instance; K : Key);
+      --  Removes the latest inserted element pointer associated with the
+      --  given key if any, does nothing if none.
+
+      function Get_First (T : Instance) return Elmt_Ptr;
+      --  Returns Null_Ptr if the Htable is empty, otherwise returns one
+      --  unspecified element. There is no guarantee that 2 calls to this
+      --  function will return the same element.
+
+      function Get_Next (T : Instance) return Elmt_Ptr;
+      --  Returns an unspecified element that has not been returned by the
+      --  same function since the last call to Get_First or Null_Ptr if
+      --  there is no such element or Get_First has never been called. If
+      --  there is no call to 'Set' in between Get_Next calls, all the
+      --  elements of the Htable will be traversed.
+
+   private
+      type Table_Type is array (Header_Num) of Elmt_Ptr;
+
+      type Instance_Data is record
+         Table            : Table_Type;
+         Iterator_Index   : Header_Num;
+         Iterator_Ptr     : Elmt_Ptr;
+         Iterator_Started : Boolean := False;
+      end record;
+
+      type Instance is access all Instance_Data;
+
+      Nil : constant Instance := null;
+   end Static_HTable;
+
+   -------------------
+   -- Simple_HTable --
+   -------------------
+
+   --  A simple hash table abstraction, easy to instantiate, easy to use.
+   --  The table associates one element to one key with the procedure Set.
+   --  Get retrieves the Element stored for a given Key. The efficiency of
+   --  retrieval is function of the size of the Table parameterized by
+   --  Header_Num and the hashing function Hash.
+
+   generic
+      type Header_Num is range <>;
+      --  An integer type indicating the number and range of hash headers
+
+      type Element is private;
+      --  The type of element to be stored
+
+      No_Element : Element;
+      --  The object that is returned by Get when no element has been set for
+      --  a given key
+
+      type Key is private;
+      with function Hash  (F : Key)      return Header_Num;
+      with function Equal (F1, F2 : Key) return Boolean;
+
+   package Simple_HTable is
+
+      type Instance is private;
+      Nil : constant Instance;
+
+      type Key_Option (Present : Boolean := False) is record
+         case Present is
+            when True  => K : Key;
+            when False => null;
+         end case;
+      end record;
+
+      procedure Set (T : in out Instance; K : Key; E : Element);
+      --  Associates an element with a given key. Overrides any previously
+      --  associated element.
+
+      procedure Reset (T : in out Instance);
+      --  Releases all memory associated with the table. The table can be
+      --  reused after this call (it is automatically allocated on the first
+      --  access to the table).
+
+      function Get (T : Instance; K : Key) return Element;
+      --  Returns the Element associated with a key or No_Element if the given
+      --  key has not associated element
+
+      procedure Remove (T : Instance; K : Key);
+      --  Removes the latest inserted element pointer associated with the given
+      --  key if any, does nothing if none.
+
+      function Get_First (T : Instance) return Element;
+      --  Returns No_Element if the Htable is empty, otherwise returns one
+      --  unspecified element. There is no guarantee that two calls to this
+      --  function will return the same element, if the Htable has been
+      --  modified between the two calls.
+
+      function Get_First_Key (T : Instance) return Key_Option;
+      --  Returns an option type giving an unspecified key. If the Htable
+      --  is empty, the discriminant will have field Present set to False,
+      --  otherwise its Present field is set to True and the field K contains
+      --  the key. There is no guarantee that two calls to this function will
+      --  return the same key, if the Htable has been modified between the two
+      --  calls.
+
+      function Get_Next (T : Instance) return Element;
+      --  Returns an unspecified element that has not been returned by the
+      --  same function since the last call to Get_First or No_Element if
+      --  there is no such element. If there is no call to 'Set' in between
+      --  Get_Next calls, all the elements of the Htable will be traversed.
+      --  To guarantee that all the elements of the Htable will be traversed,
+      --  no modification of the Htable (Set, Reset, Remove) should occur
+      --  between a call to Get_First and subsequent consecutive calls to
+      --  Get_Next, until one of these calls returns No_Element.
+
+      function Get_Next_Key (T : Instance) return Key_Option;
+      --  Same as Get_Next except that this returns an option type having field
+      --  Present set either to False if there no key never returned before by
+      --  either Get_First_Key or this very same function, or to True if there
+      --  is one, with the field K containing the key specified as before. The
+      --  same restrictions apply as Get_Next.
+
+   private
+
+      type Element_Wrapper;
+      type Elmt_Ptr is access all Element_Wrapper;
+      type Element_Wrapper is record
+         K    : Key;
+         E    : Element;
+         Next : Elmt_Ptr;
+      end record;
+
+      procedure Set_Next (E : Elmt_Ptr; Next : Elmt_Ptr);
+      function  Next     (E : Elmt_Ptr) return Elmt_Ptr;
+      function  Get_Key  (E : Elmt_Ptr) return Key;
+
+      package Tab is new Static_HTable
+        (Header_Num => Header_Num,
+         Element    => Element_Wrapper,
+         Elmt_Ptr   => Elmt_Ptr,
+         Null_Ptr   => null,
+         Set_Next   => Set_Next,
+         Next       => Next,
+         Key        => Key,
+         Get_Key    => Get_Key,
+         Hash       => Hash,
+         Equal      => Equal);
+
+      type Instance is new Tab.Instance;
+      Nil : constant Instance := Instance (Tab.Nil);
+
+   end Simple_HTable;
+
+end GNAT.Dynamic_HTables;