--
-- This is the body of the integer stack package. This file is named
-- int_stack.adb.
--
package body G_Stack is
-- Push an integer. If the stack is already full, ignore the push.
procedure Push(S: in out Gen_Stack; I: Item_Type) is
begin
if S.Size < Max_Size then
S.Size := S.Size + 1;
S.Data(S.Size) := I;
else
raise Stack_Overflow;
end if;
end Push;
-- Pop and integer. If the stack is empty, a zeor is placed in I.
procedure Pop(S: in out Gen_Stack; I: out Item_Type) is
begin
if S.Size > 0 then
I := S.Data(S.Size);
S.Size := S.Size - 1;
else
raise Stack_Underflow;
end if;
end Pop;
-- Get the top item, or 0 if the stack is empty.
function Top(S: Gen_Stack) return Item_Type is
begin
if S.Size > 0 then
return S.Data(S.Size);
else
raise Stack_Underflow;
end if;
end Top;
-- Tell if the stack is empty.
function Empty(S: Gen_Stack) return Boolean is
begin
return S.Size = 0;
end Empty;
-- Tell if the stack is empty.
function Full(S: Gen_Stack) return Boolean is
begin
return S.Size = Max_Size;
end Full;
-- Make the stack empty.
procedure Clean(S: in out Gen_Stack) is
begin
S.Size := 0;
end Clean;
end G_Stack;