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Diffstat (limited to 'gcc-4.8.3/gcc/ada/g-table.adb')
| -rw-r--r-- | gcc-4.8.3/gcc/ada/g-table.adb | 329 |
1 files changed, 329 insertions, 0 deletions
diff --git a/gcc-4.8.3/gcc/ada/g-table.adb b/gcc-4.8.3/gcc/ada/g-table.adb new file mode 100644 index 000000000..eeaa59bb6 --- /dev/null +++ b/gcc-4.8.3/gcc/ada/g-table.adb @@ -0,0 +1,329 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME COMPONENTS -- +-- -- +-- G N A T . T A B L E -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1998-2010, 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 3, 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. -- +-- -- +-- 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/>. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +with System; use System; +with System.Memory; use System.Memory; + +with Ada.Unchecked_Conversion; + +package body GNAT.Table is + + Min : constant Integer := Integer (Table_Low_Bound); + -- Subscript of the minimum entry in the currently allocated table + + Max : Integer; + -- Subscript of the maximum entry in the currently allocated table + + Length : Integer := 0; + -- Number of entries in currently allocated table. The value of zero + -- ensures that we initially allocate the table. + + Last_Val : Integer; + -- Current value of Last + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Reallocate; + -- Reallocate the existing table according to the current value stored + -- in Max. Works correctly to do an initial allocation if the table + -- is currently null. + + pragma Warnings (Off); + -- Turn off warnings. The following unchecked conversions are only used + -- internally in this package, and cannot never result in any instances + -- of improperly aliased pointers for the client of the package. + + function To_Address is new Ada.Unchecked_Conversion (Table_Ptr, Address); + function To_Pointer is new Ada.Unchecked_Conversion (Address, Table_Ptr); + + pragma Warnings (On); + + -------------- + -- Allocate -- + -------------- + + function Allocate (Num : Integer := 1) return Table_Index_Type is + Old_Last : constant Integer := Last_Val; + + begin + Last_Val := Last_Val + Num; + + if Last_Val > Max then + Reallocate; + end if; + + return Table_Index_Type (Old_Last + 1); + end Allocate; + + ------------ + -- Append -- + ------------ + + procedure Append (New_Val : Table_Component_Type) is + begin + Set_Item (Table_Index_Type (Last_Val + 1), New_Val); + end Append; + + ---------------- + -- Append_All -- + ---------------- + + procedure Append_All (New_Vals : Table_Type) is + begin + for J in New_Vals'Range loop + Append (New_Vals (J)); + end loop; + end Append_All; + + -------------------- + -- Decrement_Last -- + -------------------- + + procedure Decrement_Last is + begin + Last_Val := Last_Val - 1; + end Decrement_Last; + + ---------- + -- Free -- + ---------- + + procedure Free is + begin + Free (To_Address (Table)); + Table := null; + Length := 0; + end Free; + + -------------------- + -- Increment_Last -- + -------------------- + + procedure Increment_Last is + begin + Last_Val := Last_Val + 1; + + if Last_Val > Max then + Reallocate; + end if; + end Increment_Last; + + ---------- + -- Init -- + ---------- + + procedure Init is + Old_Length : constant Integer := Length; + + begin + Last_Val := Min - 1; + Max := Min + Table_Initial - 1; + Length := Max - Min + 1; + + -- If table is same size as before (happens when table is never + -- expanded which is a common case), then simply reuse it. Note + -- that this also means that an explicit Init call right after + -- the implicit one in the package body is harmless. + + if Old_Length = Length then + return; + + -- Otherwise we can use Reallocate to get a table of the right size. + -- Note that Reallocate works fine to allocate a table of the right + -- initial size when it is first allocated. + + else + Reallocate; + end if; + end Init; + + ---------- + -- Last -- + ---------- + + function Last return Table_Index_Type is + begin + return Table_Index_Type (Last_Val); + end Last; + + ---------------- + -- Reallocate -- + ---------------- + + procedure Reallocate is + New_Size : size_t; + + begin + if Max < Last_Val then + pragma Assert (not Locked); + + while Max < Last_Val loop + + -- Increase length using the table increment factor, but make + -- sure that we add at least ten elements (this avoids a loop + -- for silly small increment values) + + Length := Integer'Max + (Length * (100 + Table_Increment) / 100, + Length + 10); + Max := Min + Length - 1; + end loop; + end if; + + New_Size := + size_t ((Max - Min + 1) * + (Table_Type'Component_Size / Storage_Unit)); + + if Table = null then + Table := To_Pointer (Alloc (New_Size)); + + elsif New_Size > 0 then + Table := + To_Pointer (Realloc (Ptr => To_Address (Table), + Size => New_Size)); + end if; + + if Length /= 0 and then Table = null then + raise Storage_Error; + end if; + + end Reallocate; + + ------------- + -- Release -- + ------------- + + procedure Release is + begin + Length := Last_Val - Integer (Table_Low_Bound) + 1; + Max := Last_Val; + Reallocate; + end Release; + + -------------- + -- Set_Item -- + -------------- + + procedure Set_Item + (Index : Table_Index_Type; + Item : Table_Component_Type) + is + -- If Item is a value within the current allocation, and we are going to + -- reallocate, then we must preserve an intermediate copy here before + -- calling Increment_Last. Otherwise, if Table_Component_Type is passed + -- by reference, we are going to end up copying from storage that might + -- have been deallocated from Increment_Last calling Reallocate. + + subtype Allocated_Table_T is + Table_Type (Table'First .. Table_Index_Type (Max + 1)); + -- A constrained table subtype one element larger than the currently + -- allocated table. + + Allocated_Table_Address : constant System.Address := + Table.all'Address; + -- Used for address clause below (we can't use non-static expression + -- Table.all'Address directly in the clause because some older versions + -- of the compiler do not allow it). + + Allocated_Table : Allocated_Table_T; + pragma Import (Ada, Allocated_Table); + pragma Suppress (Range_Check, On => Allocated_Table); + for Allocated_Table'Address use Allocated_Table_Address; + -- Allocated_Table represents the currently allocated array, plus + -- one element (the supplementary element is used to have a + -- convenient way of computing the address just past the end of the + -- current allocation). Range checks are suppressed because this unit + -- uses direct calls to System.Memory for allocation, and this can + -- yield misaligned storage (and we cannot rely on the bootstrap + -- compiler supporting specifically disabling alignment checks, so we + -- need to suppress all range checks). It is safe to suppress this check + -- here because we know that a (possibly misaligned) object of that type + -- does actually exist at that address. + -- ??? We should really improve the allocation circuitry here to + -- guarantee proper alignment. + + Need_Realloc : constant Boolean := Integer (Index) > Max; + -- True if this operation requires storage reallocation (which may + -- involve moving table contents around). + + begin + -- If we're going to reallocate, check whether Item references an + -- element of the currently allocated table. + + if Need_Realloc + and then Allocated_Table'Address <= Item'Address + and then Item'Address < + Allocated_Table (Table_Index_Type (Max + 1))'Address + then + -- If so, save a copy on the stack because Increment_Last will + -- reallocate storage and might deallocate the current table. + + declare + Item_Copy : constant Table_Component_Type := Item; + begin + Set_Last (Index); + Table (Index) := Item_Copy; + end; + + else + -- Here we know that either we won't reallocate (case of Index < Max) + -- or that Item is not in the currently allocated table. + + if Integer (Index) > Last_Val then + Set_Last (Index); + end if; + + Table (Index) := Item; + end if; + end Set_Item; + + -------------- + -- Set_Last -- + -------------- + + procedure Set_Last (New_Val : Table_Index_Type) is + begin + if Integer (New_Val) < Last_Val then + Last_Val := Integer (New_Val); + else + Last_Val := Integer (New_Val); + + if Last_Val > Max then + Reallocate; + end if; + end if; + end Set_Last; + +begin + Init; +end GNAT.Table; |