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108 | ------------------------------------------------------------------------------
-- G N A T C O L L --
-- --
-- Copyright (C) 2010-2017, AdaCore --
-- --
-- This library is free software; you can redistribute it and/or modify it --
-- under terms of the GNU General Public License as published by the Free --
-- Software Foundation; either version 3, or (at your option) any later --
-- version. This library is distributed in the hope that it will be useful, --
-- but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHAN- --
-- TABILITY 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/>. --
-- --
------------------------------------------------------------------------------
-- A symbol table
-- Equal strings are always represented with the same pointer, thus
-- reducing the amount of memory to store multiple instances of the same
-- string, and speeding up comparison (since you only need to compare the
-- pointer, not the string itself).
with Ada.Containers.Hashed_Sets;
with GNATCOLL.Utils; use GNATCOLL.Utils;
package GNATCOLL.Symbols is
type Symbol_Table_Record (<>) is tagged private;
type Symbol_Table_Access is access all Symbol_Table_Record'Class;
-- A symbol table associating integers with strings.
-- By default, this is not task safe, so you will need to extend this if
-- the symbol is to be shared between multiple tasks.
type Symbol is private;
No_Symbol : constant Symbol;
Empty_String : constant Symbol;
function Allocate return Symbol_Table_Access;
-- Allocate a new symbol table
function Find
(Table : access Symbol_Table_Record;
Str : String) return Symbol;
-- Return the internal version of Str.
-- Comparing Symbol is the same as comparing the string itself, but much
-- faster.
function Get
(Sym : Symbol; Empty_If_Null : Boolean := True)
return Cst_String_Access;
pragma Inline_Always (Get);
-- The string associated with the symbol.
-- The returned string must not be deallocated, it points to internal data.
-- For No_Symbol, this returns null or the empty string, depending on
-- Empty_If_Null.
procedure Free (Table : in out Symbol_Table_Record);
procedure Free (Table : in out Symbol_Table_Access);
-- Free the table
function Hash (S : Symbol) return Ada.Containers.Hash_Type;
-- Returns a hash for the symbol, in case you need to create your own
-- hash tables.
function Debug_Print (S : Symbol) return String;
-- Return a displaying version of symbol (debugging purposes only)
procedure Display_Stats (Self : access Symbol_Table_Record);
-- Display statistics about the table.
-- This is meant for debug purposes only, and the output might change from
-- one version to the next.
private
type Symbol is new Cst_String_Access;
Cst_Empty_String : aliased constant String := "";
No_Symbol : constant Symbol := null;
Empty_String : constant Symbol := Cst_Empty_String'Access;
function Hash (Str : Cst_String_Access) return Ada.Containers.Hash_Type;
function Key_Equal (Key1, Key2 : Cst_String_Access) return Boolean;
pragma Inline (Hash, Key_Equal);
package String_Htable is new Ada.Containers.Hashed_Sets
(Element_Type => Cst_String_Access,
Hash => Hash,
Equivalent_Elements => Key_Equal,
"=" => "=");
type Symbol_Table_Record is tagged record
Hash : String_Htable.Set;
Calls_To_Find : Natural := 0;
Total_Size : Long_Long_Integer := 0;
Size_Saved : Long_Long_Integer := 0;
end record;
end GNATCOLL.Symbols;
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