Mercurial > hg > CbC > CbC_gcc
diff gcc/ada/libgnat/g-dyntab.ads @ 111:04ced10e8804
gcc 7
author | kono |
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date | Fri, 27 Oct 2017 22:46:09 +0900 |
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children | 84e7813d76e9 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/gcc/ada/libgnat/g-dyntab.ads Fri Oct 27 22:46:09 2017 +0900 @@ -0,0 +1,293 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- G N A T . D Y N A M I C _ T A B L E S -- +-- -- +-- S p e c -- +-- -- +-- Copyright (C) 2000-2017, 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. -- +-- -- +------------------------------------------------------------------------------ + +-- 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 Ada.Containers.Vectors. + +-- Note that these three interfaces should remain synchronized to keep as much +-- coherency as possible among these related units: +-- +-- GNAT.Dynamic_Tables +-- GNAT.Table +-- Table (the compiler unit) + +pragma Compiler_Unit_Warning; + +with Ada.Unchecked_Conversion; + +generic + type Table_Component_Type is private; + type Table_Index_Type is range <>; + + Table_Low_Bound : Table_Index_Type := Table_Index_Type'First; + Table_Initial : Positive := 8; + Table_Increment : Natural := 100; + Release_Threshold : Natural := 0; -- size in bytes + +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. The effect is roughly to declare: + + -- Table : array (Table_Low_Bound .. <>) of Table_Component_Type; + + -- The lower bound of Table_Index_Type is ignored. + + -- Table_Component_Type must not be a type with controlled parts. + + -- The Table_Initial value controls the allocation of the table when it is + -- first allocated. + + -- 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. + + -- WARNING: On HPPA, the virtual addressing approach used in this unit is + -- incompatible with the indexing instructions on the HPPA. So when using + -- this unit, compile your application with -mdisable-indexing. + + -- WARNING: If the table is reallocated, then the address of all its + -- components will change. So do not capture the address of an element + -- and then use the address later after the table may be reallocated. One + -- tricky case of this is passing an element of the table to a subprogram + -- by reference where the table gets reallocated during the execution of + -- the subprogram. The best rule to follow is never to pass a table element + -- as a parameter except for the case of IN mode parameters with scalar + -- values. + + pragma Assert (Table_Low_Bound /= Table_Index_Type'Base'First); + + subtype Valid_Table_Index_Type is Table_Index_Type'Base + range Table_Low_Bound .. Table_Index_Type'Base'Last; + subtype Table_Last_Type is Table_Index_Type'Base + range Table_Low_Bound - 1 .. Table_Index_Type'Base'Last; + + -- Table_Component_Type must not be a type with controlled parts. + + -- The Table_Initial value controls the allocation of the table when it is + -- first allocated. + + -- 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 (Valid_Table_Index_Type range <>) of Table_Component_Type; + subtype Big_Table_Type is + Table_Type (Table_Low_Bound .. Valid_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. + + -- To get subscript checking, rename a slice of the Table, like this: + + -- Table : Table_Type renames T.Table (First .. Last (T)); + + -- and then refer to components of Table. + + type Table_Ptr is access all Big_Table_Type; + for Table_Ptr'Storage_Size use 0; + -- 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 + + -- Private use only: + subtype Empty_Table_Array_Type is + Table_Type (Table_Low_Bound .. Table_Low_Bound - 1); + type Empty_Table_Array_Ptr is access all Empty_Table_Array_Type; + Empty_Table_Array : aliased Empty_Table_Array_Type; + function Empty_Table_Array_Ptr_To_Table_Ptr is + new Ada.Unchecked_Conversion (Empty_Table_Array_Ptr, Table_Ptr); + Empty_Table_Ptr : constant Table_Ptr := + Empty_Table_Array_Ptr_To_Table_Ptr (Empty_Table_Array'Access); + -- End private use only. The above are used to initialize Table to point to + -- an empty array. + + type Instance is record + Table : Table_Ptr := Empty_Table_Ptr; + -- The table itself. The lower bound is the value of First. 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. + -- + -- It's a good idea to access this via a renaming of a slice, in order + -- to ensure bounds checking, as in: + -- + -- Tab : Table_Type renames X.Table (First .. X.Last); + -- + -- Note: The Table component must come first. See declarations of + -- SCO_Unit_Table and SCO_Table in scos.h. + + Locked : Boolean := False; + -- Table reallocation is permitted only if this is False. A client may + -- set Locked to True, in which case any operation that might expand or + -- shrink the table will cause an assertion failure. While a table is + -- locked, its address in memory remains fixed and unchanging. + + P : Table_Private; + end record; + + function Is_Empty (T : Instance) return Boolean; + pragma Inline (Is_Empty); + + procedure Init (T : in out Instance); + -- Reinitializes the table to empty. There is no need to call this before + -- using a table; tables default to empty. + + procedure Free (T : in out Instance) renames Init; + + function First return Table_Index_Type; + pragma Inline (First); + -- Export First as synonym for Table_Low_Bound (parallel with use of Last) + + function Last (T : Instance) return Table_Last_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. + + procedure Release (T : in out Instance); + -- Storage is allocated in chunks according to the values given in the + -- Table_Initial and Table_Increment parameters. If Release_Threshold is + -- 0 or the length of the table does not exceed this threshold then a call + -- to Release releases all storage that is allocated, but is not logically + -- part of the current array value; otherwise the call to Release leaves + -- the current array value plus 0.1% of the current table length free + -- elements located at the end of the table. This parameter facilitates + -- reopening large tables and adding a few elements without allocating a + -- chunk of memory. In both cases current array values are not affected by + -- this call. + + procedure Set_Last (T : in out Instance; New_Val : Table_Last_Type); + pragma Inline (Set_Last); + -- This procedure sets Last to the indicated value. If necessary the table + -- is reallocated to accommodate 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); + -- Appends New_Val onto the end of the table + -- Equivalent to: + -- Increment_Last (T); + -- T.Table (T.Last) := New_Val; + + procedure Append_All (T : in out Instance; New_Vals : Table_Type); + -- Appends all components of New_Vals + + procedure Set_Item + (T : in out Instance; + Index : Valid_Table_Index_Type; + Item : Table_Component_Type); + pragma Inline (Set_Item); + -- Put Item in the table at position Index. If Index points to an existing + -- item (i.e. it is in the range First .. Last (T)), the item is replaced. + -- Otherwise (i.e. Index > Last (T)), the table is expanded, and Last is + -- set to Index. + + procedure Move (From, To : in out Instance); + -- Moves from From to To, and sets From to empty + + procedure Allocate (T : in out Instance; Num : Integer := 1); + pragma Inline (Allocate); + -- Adds Num to Last + + generic + with procedure Action + (Index : Valid_Table_Index_Type; + Item : Table_Component_Type; + Quit : in out Boolean) is <>; + procedure For_Each (Table : Instance); + -- Calls procedure Action for each component of the table, or until one of + -- these calls set Quit to True. + + generic + with function Lt (Comp1, Comp2 : Table_Component_Type) return Boolean; + procedure Sort_Table (Table : in out Instance); + -- This procedure sorts the components of the table into ascending order + -- making calls to Lt to do required comparisons, and using assignments + -- to move components around. The Lt function returns True if Comp1 is + -- less than Comp2 (in the sense of the desired sort), and False if Comp1 + -- is greater than Comp2. For equal objects it does not matter if True or + -- False is returned (it is slightly more efficient to return False). The + -- sort is not stable (the order of equal items in the table is not + -- preserved). + +private + + type Table_Private is record + Last_Allocated : Table_Last_Type := Table_Low_Bound - 1; + -- Subscript of the maximum entry in the currently allocated table. + -- Initial value ensures that we initially allocate the table. + + Last : Table_Last_Type := Table_Low_Bound - 1; + -- Current value of Last function + + -- Invariant: Last <= Last_Allocated + end record; + +end GNAT.Dynamic_Tables;