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------------------------------------------------------------------------------
-- --
-- --
-- ASIS UTILITY LIBRARY COMPONENTS --
-- --
-- A S I S _ U L . S I M P L E _ S T A C K S --
-- --
-- B o d y --
-- --
-- Copyright (C) 2012-2014, AdaCore --
-- --
-- Asis Utility Library (ASIS UL) is free software; you can redistribute it --
-- and/or modify it under terms of the GNU General Public License as --
-- published by the Free Software Foundation; either version 3, or (at your --
-- option) any later version. ASIS UL 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 distributed with GNAT; see file --
-- COPYING3. If not, go to http://www.gnu.org/licenses for a complete copy --
-- of the license. --
-- --
-- ASIS UL is maintained by AdaCore (http://www.adacore.com). --
-- --
------------------------------------------------------------------------------
pragma Ada_2012;
package body ASIS_UL.Simple_Stacks is
--------------------
-- Is_Empty_Stack --
--------------------
function Is_Empty_Stack (S : in out Simple_Stack) return Boolean is
begin
return Is_Empty (S);
end Is_Empty_Stack;
---------
-- Pop --
---------
function Pop (S : in out Simple_Stack) return Element_Type is
Result : Element_Type := No_Element;
begin
if not Is_Empty (S) then
Result := Last_Element (S);
Delete_Last (S);
end if;
return Result;
end Pop;
---------
-- Pop --
---------
procedure Pop (S : in out Simple_Stack) is
begin
if not Is_Empty (S) then
Delete_Last (S);
end if;
end Pop;
----------
-- Push --
----------
procedure Push (S : in out Simple_Stack; Elem : Element_Type) is
begin
Append (S, Elem);
end Push;
----------
-- Size --
----------
function Size (S : in out Simple_Stack) return Natural is
begin
return Natural (Length (S));
end Size;
---------
-- Top --
---------
function Top
(S : in out Simple_Stack;
Step_Down : Natural := 0)
return Element_Type
is
Depth : constant Natural := Size (S);
begin
if Depth = 0 or else Step_Down > Depth then
return No_Element;
else
return Element (S, Last_Index (S) - Step_Down);
end if;
end Top;
end ASIS_UL.Simple_Stacks;
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