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Diffstat (limited to 'src/dyn_tables.ads')
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diff --git a/src/dyn_tables.ads b/src/dyn_tables.ads new file mode 100644 index 000000000..600e2bf85 --- /dev/null +++ b/src/dyn_tables.ads @@ -0,0 +1,105 @@ +-- Efficient expandable one dimensional array type. +-- Copyright (C) 2015 - 2016 Tristan Gingold +-- +-- GHDL is free software; you can redistribute it and/or modify it under +-- the terms of the GNU General Public License as published by the Free +-- Software Foundation; either version 2, or (at your option) any later +-- version. +-- +-- GHDL is distributed in the hope that it will be useful, but WITHOUT 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 +-- along with GHDL; see the file COPYING. If not, write to the Free +-- Software Foundation, 59 Temple Place - Suite 330, Boston, MA +-- 02111-1307, USA. + +-- This package mimics GNAT.Table, but: +-- - the index type can be any discrete type (in particular a modular type) +-- - the increment is not used +-- - the interface is simplified. +generic + -- This package creates: + -- array (Table_Index_Type range Table_Low_Bound .. <>) + -- of Table_Component_Type; + type Table_Component_Type is private; + type Table_Index_Type is (<>); + + -- The lowest bound of the array. Note that Table_Low_Bound shouldn't be + -- Table_Index_Type'First, as otherwise Last may raise constraint error + -- when the table is empty. + Table_Low_Bound : Table_Index_Type; + + -- Initial number of elements. + Table_Initial : Positive; + +package Dyn_Tables is + -- Ada type for the array. + type Table_Type is + array (Table_Index_Type range <>) of Table_Component_Type; + -- Fat subtype (so that the access is thin). + subtype Big_Table_Type is + Table_Type (Table_Low_Bound .. Table_Index_Type'Last); + + -- Access type for the vector. This is a thin pointer so that it is + -- compatible with C pointer, as this package uses malloc/realloc/free for + -- memory management. + type Table_Thin_Ptr is access all Big_Table_Type; + pragma Convention (C, Table_Thin_Ptr); + for Table_Thin_Ptr'Storage_Size use 0; + + -- Non user visible data. + type Instance_Private is private; + + -- Type for the dynamic table. + type Instance is record + -- Pointer to the table. Note that the use of a thin pointer to the + -- largest array, this implementation bypasses Ada index checks. + Table : Table_Thin_Ptr := null; + + -- Private data. + Priv : Instance_Private; + end record; + + -- Initialize the table. This is done automatically at elaboration. + procedure Init (T : in out Instance); + + -- Logical bounds of the array. + First : constant Table_Index_Type := Table_Low_Bound; + function Last (T : Instance) return Table_Index_Type; + pragma Inline (Last); + + -- Deallocate all the memory. Makes the array unusable until the next + -- call to Init. + procedure Free (T : in out Instance); + + -- Increase by 1 the length of the array. This may allocate memory. + procedure Increment_Last (T : in out Instance); + pragma Inline (Increment_Last); + + -- Decrease by 1 the length of the array. + procedure Decrement_Last (T : in out Instance); + pragma Inline (Decrement_Last); + + -- Increase or decrease the length of the array by specifying the upper + -- bound. + procedure Set_Last (T : in out Instance; Index : Table_Index_Type); + + -- Append VAL to the array. This always increase the length of the array. + procedure Append (T : in out Instance; Val : Table_Component_Type); + pragma Inline (Append); + + -- Increase by NUM the length of the array. + procedure Allocate (T : in out Instance; Num : Natural := 1); + +private + type Instance_Private is record + -- Number of allocated elements in the table. + Length : Natural := 0; + + -- Number of used elements in the table. + Last_Pos : Natural := 0; + end record; +end Dyn_Tables; |