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diff --git a/gcc/ada/g-dyntab.ads b/gcc/ada/g-dyntab.ads new file mode 100644 index 00000000000..65a25e75884 --- /dev/null +++ b/gcc/ada/g-dyntab.ads @@ -0,0 +1,195 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- G N A T . D Y N A M I C _ T A B L E S -- +-- -- +-- S p e c -- +-- -- +-- $Revision: 1.11 $ +-- -- +-- Copyright (C) 2000-2001 Ada Core Technologies, Inc. -- +-- -- +-- 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 2, 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. See the GNU General Public License -- +-- for more details. You should have received a copy of the GNU General -- +-- Public License distributed with GNAT; see file COPYING. If not, write -- +-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- +-- MA 02111-1307, USA. -- +-- -- +-- As a special exception, if other files instantiate generics from this -- +-- unit, or you link this unit with other files to produce an executable, -- +-- this unit does not by itself cause the resulting executable to be -- +-- covered by the GNU General Public License. This exception does not -- +-- however invalidate any other reasons why the executable file might be -- +-- covered by the GNU Public License. -- +-- -- +-- GNAT is maintained by Ada Core Technologies Inc (http://www.gnat.com). -- +-- -- +------------------------------------------------------------------------------ + +-- Resizable one dimensional array support + +-- This package provides an implementation of dynamically resizable one +-- dimensional arrays. The idea is to mimic the normal Ada semantics for +-- arrays as closely as possible with the one additional capability of +-- dynamically modifying the value of the Last attribute. + +-- This package provides a facility similar to that of GNAT.Table, except +-- that this package declares a type that can be used to define dynamic +-- instances of the table, while an instantiation of GNAT.Table creates a +-- single instance of the table type. + +-- Note that this interface should remain synchronized with those in +-- GNAT.Table and the GNAT compiler source unit Table to keep as much +-- coherency as possible between these three related units. + +generic + type Table_Component_Type is private; + type Table_Index_Type is range <>; + + Table_Low_Bound : Table_Index_Type; + Table_Initial : Positive; + Table_Increment : Natural; + +package GNAT.Dynamic_Tables is + + -- Table_Component_Type and Table_Index_Type specify the type of the + -- array, Table_Low_Bound is the lower bound. Index_type must be an + -- integer type. The effect is roughly to declare: + + -- Table : array (Table_Low_Bound .. <>) of Table_Component_Type; + + -- Table_Component_Type may be any Ada type, except that controlled + -- types are not supported. Note however that default initialization + -- will NOT occur for array components. + + -- The Table_Initial values controls the allocation of the table when + -- it is first allocated, either by default, or by an explicit Init + -- call. + + -- The Table_Increment value controls the amount of increase, if the + -- table has to be increased in size. The value given is a percentage + -- value (e.g. 100 = increase table size by 100%, i.e. double it). + + -- The Last and Set_Last subprograms provide control over the current + -- logical allocation. They are quite efficient, so they can be used + -- freely (expensive reallocation occurs only at major granularity + -- chunks controlled by the allocation parameters). + + -- Note: we do not make the table components aliased, since this would + -- restrict the use of table for discriminated types. If it is necessary + -- to take the access of a table element, use Unrestricted_Access. + + type Table_Type is + array (Table_Index_Type range <>) of Table_Component_Type; + + subtype Big_Table_Type is + Table_Type (Table_Low_Bound .. Table_Index_Type'Last); + -- We work with pointers to a bogus array type that is constrained + -- with the maximum possible range bound. This means that the pointer + -- is a thin pointer, which is more efficient. Since subscript checks + -- in any case must be on the logical, rather than physical bounds, + -- safety is not compromised by this approach. + + type Table_Ptr is access all Big_Table_Type; + -- The table is actually represented as a pointer to allow + -- reallocation. + + type Table_Private is private; + -- table private data that is not exported in Instance. + + type Instance is record + Table : aliased Table_Ptr := null; + -- The table itself. The lower bound is the value of Low_Bound. + -- Logically the upper bound is the current value of Last (although + -- the actual size of the allocated table may be larger than this). + -- The program may only access and modify Table entries in the + -- range First .. Last. + + P : Table_Private; + end record; + + procedure Init (T : in out Instance); + -- This procedure allocates a new table of size Initial (freeing any + -- previously allocated larger table). Init must be called before using + -- the table. Init is convenient in reestablishing a table for new use. + + function Last (T : in Instance) return Table_Index_Type; + pragma Inline (Last); + -- Returns the current value of the last used entry in the table, + -- which can then be used as a subscript for Table. Note that the + -- only way to modify Last is to call the Set_Last procedure. Last + -- must always be used to determine the logically last entry. + + procedure Release (T : in out Instance); + -- Storage is allocated in chunks according to the values given in the + -- Initial and Increment parameters. A call to Release releases all + -- storage that is allocated, but is not logically part of the current + -- array value. Current array values are not affected by this call. + + procedure Free (T : in out Instance); + -- Free all allocated memory for the table. A call to init is required + -- before any use of this table after calling Free. + + First : constant Table_Index_Type := Table_Low_Bound; + -- Export First as synonym for Low_Bound (parallel with use of Last) + + procedure Set_Last (T : in out Instance; New_Val : Table_Index_Type); + pragma Inline (Set_Last); + -- This procedure sets Last to the indicated value. If necessary the + -- table is reallocated to accomodate the new value (i.e. on return + -- the allocated table has an upper bound of at least Last). If + -- Set_Last reduces the size of the table, then logically entries are + -- removed from the table. If Set_Last increases the size of the + -- table, then new entries are logically added to the table. + + procedure Increment_Last (T : in out Instance); + pragma Inline (Increment_Last); + -- Adds 1 to Last (same as Set_Last (Last + 1). + + procedure Decrement_Last (T : in out Instance); + pragma Inline (Decrement_Last); + -- Subtracts 1 from Last (same as Set_Last (Last - 1). + + procedure Append (T : in out Instance; New_Val : Table_Component_Type); + pragma Inline (Append); + -- Equivalent to: + -- Increment_Last (T); + -- T.Table (T.Last) := New_Val; + -- i.e. the table size is increased by one, and the given new item + -- stored in the newly created table element. + + procedure Set_Item + (T : in out Instance; + Index : Table_Index_Type; + Item : Table_Component_Type); + pragma Inline (Set_Item); + -- Put Item in the table at position Index. The table is expanded if + -- current table length is less than Index and in that case Last is set to + -- Index. Item will replace any value already present in the table at this + -- position. + + procedure Allocate (T : in out Instance; Num : Integer := 1); + pragma Inline (Allocate); + -- Adds Num to Last. + +private + + type Table_Private is record + 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. + end record; + +end GNAT.Dynamic_Tables; |