1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2007, Free Software Foundation, 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, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, 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 Debug
; use Debug
;
36 with Output
; use Output
;
37 with System
; use System
;
38 with Tree_IO
; use Tree_IO
;
40 with System
.Memory
; use System
.Memory
;
42 with Unchecked_Conversion
;
44 pragma Elaborate_All
(Output
);
49 Min
: constant Int
:= Int
(Table_Low_Bound
);
50 -- Subscript of the minimum entry in the currently allocated table
53 -- Number of entries in currently allocated table. The value of zero
54 -- ensures that we initially allocate the table.
56 -----------------------
57 -- Local Subprograms --
58 -----------------------
61 -- Reallocate the existing table according to the current value stored
62 -- in Max. Works correctly to do an initial allocation if the table
65 function Tree_Get_Table_Address
return Address
;
66 -- Return Null_Address if the table length is zero,
67 -- Table (First)'Address if not.
69 pragma Warnings
(Off
);
70 -- Turn off warnings. The following unchecked conversions are only used
71 -- internally in this package, and cannot never result in any instances
72 -- of improperly aliased pointers for the client of the package.
74 function To_Address
is new Unchecked_Conversion
(Table_Ptr
, Address
);
75 function To_Pointer
is new Unchecked_Conversion
(Address
, Table_Ptr
);
83 procedure Append
(New_Val
: Table_Component_Type
) is
85 Set_Item
(Table_Index_Type
(Last_Val
+ 1), New_Val
);
92 procedure Decrement_Last
is
94 Last_Val
:= Last_Val
- 1;
103 Free
(To_Address
(Table
));
112 procedure Increment_Last
is
114 Last_Val
:= Last_Val
+ 1;
116 if Last_Val
> Max
then
126 Old_Length
: constant Int
:= Length
;
131 Max
:= Min
+ (Table_Initial
* Table_Factor
) - 1;
132 Length
:= Max
- Min
+ 1;
134 -- If table is same size as before (happens when table is never
135 -- expanded which is a common case), then simply reuse it. Note
136 -- that this also means that an explicit Init call right after
137 -- the implicit one in the package body is harmless.
139 if Old_Length
= Length
then
142 -- Otherwise we can use Reallocate to get a table of the right size.
143 -- Note that Reallocate works fine to allocate a table of the right
144 -- initial size when it is first allocated.
155 function Last
return Table_Index_Type
is
157 return Table_Index_Type
(Last_Val
);
164 procedure Reallocate
is
165 New_Size
: Memory
.size_t
;
168 if Max
< Last_Val
then
169 pragma Assert
(not Locked
);
171 -- Make sure that we have at least the initial allocation. This
172 -- is needed in cases where a zero length table is written out.
174 Length
:= Int
'Max (Length
, Table_Initial
);
176 -- Now increment table length until it is sufficiently large. Use
177 -- the increment value or 10, which ever is larger (the reason
178 -- for the use of 10 here is to ensure that the table does really
179 -- increase in size (which would not be the case for a table of
180 -- length 10 increased by 3% for instance).
182 while Max
< Last_Val
loop
183 Length
:= Int
'Max (Length
* (100 + Table_Increment
) / 100,
185 Max
:= Min
+ Length
- 1;
189 Write_Str
("--> Allocating new ");
190 Write_Str
(Table_Name
);
191 Write_Str
(" table, size = ");
192 Write_Int
(Max
- Min
+ 1);
198 Memory
.size_t
((Max
- Min
+ 1) *
199 (Table_Type
'Component_Size / Storage_Unit
));
202 Table
:= To_Pointer
(Alloc
(New_Size
));
204 elsif New_Size
> 0 then
206 To_Pointer
(Realloc
(Ptr
=> To_Address
(Table
),
210 if Length
/= 0 and then Table
= null then
212 Write_Str
("available memory exhausted");
215 raise Unrecoverable_Error
;
226 Length
:= Last_Val
- Int
(Table_Low_Bound
) + 1;
235 procedure Restore
(T
: Saved_Table
) is
237 Free
(To_Address
(Table
));
238 Last_Val
:= T
.Last_Val
;
241 Length
:= Max
- Min
+ 1;
248 function Save
return Saved_Table
is
252 Res
.Last_Val
:= Last_Val
;
267 (Index
: Table_Index_Type
;
268 Item
: Table_Component_Type
)
270 -- If Item is a value within the current allocation, and we are going
271 -- to reallocate, then we must preserve an intermediate copy here
272 -- before calling Increment_Last. Otherwise, if Table_Component_Type
273 -- is passed by reference, we are going to end up copying from
274 -- storage that might have been deallocated from Increment_Last
275 -- calling Reallocate.
277 subtype Allocated_Table_T
is
278 Table_Type
(Table
'First .. Table_Index_Type
(Max
+ 1));
279 -- A constrained table subtype one element larger than the currently
282 Allocated_Table_Address
: constant System
.Address
:=
284 -- Used for address clause below (we can't use non-static expression
285 -- Table.all'Address directly in the clause because some older
286 -- versions of the compiler do not allow it).
288 Allocated_Table
: Allocated_Table_T
;
289 pragma Import
(Ada
, Allocated_Table
);
290 pragma Suppress
(Range_Check
, On
=> Allocated_Table
);
291 for Allocated_Table
'Address use Allocated_Table_Address
;
292 -- Allocated_Table represents the currently allocated array, plus one
293 -- element (the supplementary element is used to have a convenient
294 -- way of computing the address just past the end of the current
295 -- allocation). Range checks are suppressed because this unit
296 -- uses direct calls to System.Memory for allocation, and this can
297 -- yield misaligned storage (and we cannot rely on the bootstrap
298 -- compiler supporting specifically disabling alignment cheks, so we
299 -- need to suppress all range checks). It is safe to suppress this
300 -- check here because we know that a (possibly misaligned) object
301 -- of that type does actually exist at that address.
302 -- ??? We should really improve the allocation circuitry here to
303 -- guarantee proper alignment.
305 Need_Realloc
: constant Boolean := Int
(Index
) > Max
;
306 -- True if this operation requires storage reallocation (which may
307 -- involve moving table contents around).
310 -- If we're going to reallocate, check wheter Item references an
311 -- element of the currently allocated table.
314 and then Allocated_Table
'Address <= Item
'Address
315 and then Item
'Address <
316 Allocated_Table
(Table_Index_Type
(Max
+ 1))'Address
318 -- If so, save a copy on the stack because Increment_Last will
319 -- reallocate storage and might deallocate the current table.
322 Item_Copy
: constant Table_Component_Type
:= Item
;
325 Table
(Index
) := Item_Copy
;
329 -- Here we know that either we won't reallocate (case of Index <
330 -- Max) or that Item is not in the currently allocated table.
332 if Int
(Index
) > Last_Val
then
336 Table
(Index
) := Item
;
344 procedure Set_Last
(New_Val
: Table_Index_Type
) is
346 if Int
(New_Val
) < Last_Val
then
347 Last_Val
:= Int
(New_Val
);
350 Last_Val
:= Int
(New_Val
);
352 if Last_Val
> Max
then
358 ----------------------------
359 -- Tree_Get_Table_Address --
360 ----------------------------
362 function Tree_Get_Table_Address
return Address
is
367 return Table
(First
)'Address;
369 end Tree_Get_Table_Address
;
375 -- Note: we allocate only the space required to accommodate the data
376 -- actually written, which means that a Tree_Write/Tree_Read sequence
377 -- does an implicit Release.
379 procedure Tree_Read
is
383 Length
:= Max
- Min
+ 1;
387 (Tree_Get_Table_Address
,
388 (Last_Val
- Int
(First
) + 1) *
389 Table_Type
'Component_Size / Storage_Unit
);
396 -- Note: we write out only the currently valid data, not the entire
397 -- contents of the allocated array. See note above on Tree_Read.
399 procedure Tree_Write
is
401 Tree_Write_Int
(Int
(Last
));
403 (Tree_Get_Table_Address
,
404 (Last_Val
- Int
(First
) + 1) *
405 Table_Type
'Component_Size / Storage_Unit
);