diff options
Diffstat (limited to 'gcc/ada/g-dynhta.ads')
| -rw-r--r-- | gcc/ada/g-dynhta.ads | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/gcc/ada/g-dynhta.ads b/gcc/ada/g-dynhta.ads new file mode 100644 index 000000000..f679d10de --- /dev/null +++ b/gcc/ada/g-dynhta.ads @@ -0,0 +1,242 @@ +------------------------------------------------------------------------------ +-- -- +-- 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) 1995-2008, 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. + +-- 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. + +with Ada.Unchecked_Deallocation; +package GNAT.Dynamic_HTables is + + ------------------- + -- 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 + 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 + -- non specified 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 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. + + private + + type Instance_Data; + 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; + + 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 + -- non specified 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_Next (T : Instance) 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. + -- 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. + + 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 Free is new + Ada.Unchecked_Deallocation (Element_Wrapper, Elmt_Ptr); + + 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; |