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diff --git a/gcc/ada/g-htable.ads b/gcc/ada/g-htable.ads new file mode 100644 index 000000000..a080ee831 --- /dev/null +++ b/gcc/ada/g-htable.ads @@ -0,0 +1,229 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME COMPONENTS -- +-- -- +-- G N A T . H T A B L E -- +-- -- +-- S p e c -- +-- -- +-- Copyright (C) 1995-2010, 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 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. -- +-- -- +-- 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 two 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 +-- complete control over allocation. + +-- Note: actual code is found in System.HTable (s-htable.ads/adb) since +-- this facility is accessed from run time routines, but clients should +-- always access the version supplied via GNAT.HTable. + +pragma Compiler_Unit; + +with System.HTable; + +package GNAT.HTable is + pragma Preelaborate; + pragma Elaborate_Body; + -- The elaborate body is because we have a dummy body to deal with + -- bootstrap path problems (we used to have a real body, and now we don't + -- need it any more, but the bootstrap requires that we have a dummy body, + -- since otherwise the old body gets picked up. + + ------------------- + -- 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 package Simple_HTable renames System.HTable.Simple_HTable; + + -- For convenience of reference here is what this package has in it: + + -- 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 + + -- procedure Set (K : Key; E : Element); + -- -- Associates an element with a given key. Overrides any previously + -- -- associated element. + + -- procedure Reset; + -- -- Removes and frees all elements in the table + + -- function Get (K : Key) return Element; + -- -- Returns the Element associated with a key or No_Element if the + -- -- given key has not associated element + + -- procedure Remove (K : Key); + -- -- Removes the latest inserted element pointer associated with the + -- -- given key if any, does nothing if none. + + -- function Get_First return Element; + -- -- Returns No_Element if the HTable is empty, otherwise returns one + -- -- non specified element. There is no guarantee that two calls to + -- -- this function will return the same element. + + -- function Get_Next return Element; + -- -- Returns a non-specified 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. + + -- procedure Get_First (K : out Key; E : out Element); + -- -- This version of the iterator returns a key/element pair. A non- + -- -- specified entry is returned, and there is no guarantee that two + -- -- calls to this procedure will return the same element. + + -- procedure Get_Next (K : out Key; E : out Element); + -- -- This version of the iterator returns a key/element pair. It + -- -- returns a non-specified element that has not been returned since + -- -- the last call to Get_First. If there is no remaining element, + -- -- then E is set to No_Element, and the value in K is undefined. + -- -- If there is no call to Set in between Get_Next calls, all the + -- -- elements of the HTable will be traversed. + + -- end Simple_HTable; + + ------------------- + -- Static_HTable -- + ------------------- + + -- A low-level Hash-Table abstraction, not as easy to instantiate as + -- Simple_HTable but designed to allow complete control over the + -- allocation of necessary data structures. Particularly useful when + -- dynamic allocation is not desired. 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 package Static_HTable renames System.HTable.Static_HTable; + + -- For convenience of reference here is what this package has in it: + + -- 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 + + -- procedure Reset; + -- -- Resets the hash table by setting all its elements to Null_Ptr. + -- -- The effect is to clear the hash table so that it can be reused. + -- -- 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 (E : Elmt_Ptr); + -- -- Insert the element pointer in the HTable + + -- function Get (K : Key) return Elmt_Ptr; + -- -- Returns the latest inserted element pointer with the given Key + -- -- or null if none. + + -- procedure Remove (K : Key); + -- -- Removes the latest inserted element pointer associated with the + -- -- given key if any, does nothing if none. + + -- function Get_First return Elmt_Ptr; + -- -- Returns Null_Ptr if the HTable is empty, otherwise returns one + -- -- non specified element. There is no guarantee that two calls to + -- -- this function will return the same element. + + -- function Get_Next return Elmt_Ptr; + -- -- Returns a non-specified 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. + + -- end Static_HTable; + + ---------- + -- Hash -- + ---------- + + -- A generic hashing function working on String keys + + generic function Hash renames System.HTable.Hash; + + -- generic + -- type Header_Num is range <>; + -- function Hash (Key : String) return Header_Num; + +end GNAT.HTable; |