1 ------------------------------------------------------------------------------
3 -- GNAT RUNTIME COMPONENTS --
5 -- G N A T . T A B L E --
10 -- Copyright (C) 1998-2001 Ada Core Technologies, Inc. --
12 -- GNAT is free software; you can redistribute it and/or modify it under --
13 -- terms of the GNU General Public License as published by the Free Soft- --
14 -- ware Foundation; either version 2, or (at your option) any later ver- --
15 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
16 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
17 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
18 -- for more details. You should have received a copy of the GNU General --
19 -- Public License distributed with GNAT; see file COPYING. If not, write --
20 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
21 -- MA 02111-1307, USA. --
23 -- As a special exception, if other files instantiate generics from this --
24 -- unit, or you link this unit with other files to produce an executable, --
25 -- this unit does not by itself cause the resulting executable to be --
26 -- covered by the GNU General Public License. This exception does not --
27 -- however invalidate any other reasons why the executable file might be --
28 -- covered by the GNU Public License. --
30 -- GNAT is maintained by Ada Core Technologies Inc (http://www.gnat.com). --
32 ------------------------------------------------------------------------------
34 with System; use System;
35 with System.Memory; use System.Memory;
36 with System.Address_To_Access_Conversions;
38 package body GNAT.Table is
40 Min : constant Integer := Integer (Table_Low_Bound);
41 -- Subscript of the minimum entry in the currently allocated table
44 -- Subscript of the maximum entry in the currently allocated table
46 Length : Integer := 0;
47 -- Number of entries in currently allocated table. The value of zero
48 -- ensures that we initially allocate the table.
51 -- Current value of Last.
53 -----------------------
54 -- Local Subprograms --
55 -----------------------
58 -- Reallocate the existing table according to the current value stored
59 -- in Max. Works correctly to do an initial allocation if the table
62 package Table_Conversions is
63 new System.Address_To_Access_Conversions (Big_Table_Type);
64 -- Address and Access conversions for a Table object.
66 function To_Address (Table : Table_Ptr) return Address;
67 pragma Inline (To_Address);
68 -- Returns the Address for the Table object.
70 function To_Pointer (Table : Address) return Table_Ptr;
71 pragma Inline (To_Pointer);
72 -- Returns the Access pointer for the Table object.
78 function Allocate (Num : Integer := 1) return Table_Index_Type is
79 Old_Last : constant Integer := Last_Val;
82 Last_Val := Last_Val + Num;
84 if Last_Val > Max then
88 return Table_Index_Type (Old_Last + 1);
95 procedure Append (New_Val : Table_Component_Type) is
98 Table (Table_Index_Type (Last_Val)) := New_Val;
105 procedure Decrement_Last is
107 Last_Val := Last_Val - 1;
116 Free (To_Address (Table));
125 procedure Increment_Last is
127 Last_Val := Last_Val + 1;
129 if Last_Val > Max then
139 Old_Length : Integer := Length;
143 Max := Min + Table_Initial - 1;
144 Length := Max - Min + 1;
146 -- If table is same size as before (happens when table is never
147 -- expanded which is a common case), then simply reuse it. Note
148 -- that this also means that an explicit Init call right after
149 -- the implicit one in the package body is harmless.
151 if Old_Length = Length then
154 -- Otherwise we can use Reallocate to get a table of the right size.
155 -- Note that Reallocate works fine to allocate a table of the right
156 -- initial size when it is first allocated.
167 function Last return Table_Index_Type is
169 return Table_Index_Type (Last_Val);
176 procedure Reallocate is
180 if Max < Last_Val then
181 pragma Assert (not Locked);
183 while Max < Last_Val loop
185 -- Increase length using the table increment factor, but make
186 -- sure that we add at least ten elements (this avoids a loop
187 -- for silly small increment values)
189 Length := Integer'Max
190 (Length * (100 + Table_Increment) / 100,
192 Max := Min + Length - 1;
197 size_t ((Max - Min + 1) *
198 (Table_Type'Component_Size / Storage_Unit));
201 Table := To_Pointer (Alloc (New_Size));
203 elsif New_Size > 0 then
205 To_Pointer (Realloc (Ptr => To_Address (Table),
209 if Length /= 0 and then Table = null then
221 Length := Last_Val - Integer (Table_Low_Bound) + 1;
231 (Index : Table_Index_Type;
232 Item : Table_Component_Type)
235 if Integer (Index) > Max then
239 Table (Index) := Item;
246 procedure Set_Last (New_Val : Table_Index_Type) is
248 if Integer (New_Val) < Last_Val then
249 Last_Val := Integer (New_Val);
251 Last_Val := Integer (New_Val);
253 if Last_Val > Max then
263 function To_Address (Table : Table_Ptr) return Address is
265 return Table_Conversions.To_Address
266 (Table_Conversions.Object_Pointer (Table));
273 function To_Pointer (Table : Address) return Table_Ptr is
275 return Table_Ptr (Table_Conversions.To_Pointer (Table));