1 ------------------------------------------------------------------------------
3 -- GNAT RUNTIME COMPONENTS --
5 -- G N A T . T A B L E --
9 -- Copyright (C) 1998-2004 Ada Core Technologies, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 with System; use System;
35 with System.Memory; use System.Memory;
37 with Unchecked_Conversion;
39 package body GNAT.Table is
41 Min : constant Integer := Integer (Table_Low_Bound);
42 -- Subscript of the minimum entry in the currently allocated table
45 -- Subscript of the maximum entry in the currently allocated table
47 Length : Integer := 0;
48 -- Number of entries in currently allocated table. The value of zero
49 -- ensures that we initially allocate the table.
52 -- Current value of Last.
54 -----------------------
55 -- Local Subprograms --
56 -----------------------
59 -- Reallocate the existing table according to the current value stored
60 -- in Max. Works correctly to do an initial allocation if the table
63 pragma Warnings (Off);
64 -- Turn off warnings. The following unchecked conversions are only used
65 -- internally in this package, and cannot never result in any instances
66 -- of improperly aliased pointers for the client of the package.
68 function To_Address is new Unchecked_Conversion (Table_Ptr, Address);
69 function To_Pointer is new Unchecked_Conversion (Address, Table_Ptr);
77 function Allocate (Num : Integer := 1) return Table_Index_Type is
78 Old_Last : constant Integer := Last_Val;
81 Last_Val := Last_Val + Num;
83 if Last_Val > Max then
87 return Table_Index_Type (Old_Last + 1);
94 procedure Append (New_Val : Table_Component_Type) is
97 Table (Table_Index_Type (Last_Val)) := New_Val;
104 procedure Decrement_Last is
106 Last_Val := Last_Val - 1;
115 Free (To_Address (Table));
124 procedure Increment_Last is
126 Last_Val := Last_Val + 1;
128 if Last_Val > Max then
138 Old_Length : constant Integer := Length;
142 Max := Min + Table_Initial - 1;
143 Length := Max - Min + 1;
145 -- If table is same size as before (happens when table is never
146 -- expanded which is a common case), then simply reuse it. Note
147 -- that this also means that an explicit Init call right after
148 -- the implicit one in the package body is harmless.
150 if Old_Length = Length then
153 -- Otherwise we can use Reallocate to get a table of the right size.
154 -- Note that Reallocate works fine to allocate a table of the right
155 -- initial size when it is first allocated.
166 function Last return Table_Index_Type is
168 return Table_Index_Type (Last_Val);
175 procedure Reallocate is
179 if Max < Last_Val then
180 pragma Assert (not Locked);
182 while Max < Last_Val loop
184 -- Increase length using the table increment factor, but make
185 -- sure that we add at least ten elements (this avoids a loop
186 -- for silly small increment values)
188 Length := Integer'Max
189 (Length * (100 + Table_Increment) / 100,
191 Max := Min + Length - 1;
196 size_t ((Max - Min + 1) *
197 (Table_Type'Component_Size / Storage_Unit));
200 Table := To_Pointer (Alloc (New_Size));
202 elsif New_Size > 0 then
204 To_Pointer (Realloc (Ptr => To_Address (Table),
208 if Length /= 0 and then Table = null then
220 Length := Last_Val - Integer (Table_Low_Bound) + 1;
230 (Index : Table_Index_Type;
231 Item : Table_Component_Type)
234 if Integer (Index) > Last_Val then
238 Table (Index) := Item;
245 procedure Set_Last (New_Val : Table_Index_Type) is
247 if Integer (New_Val) < Last_Val then
248 Last_Val := Integer (New_Val);
250 Last_Val := Integer (New_Val);
252 if Last_Val > Max then