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pragma Spark_Mode (On);
package body Predicate8_Pkg is
function Empty
(Buffer : in Ring_Buffer_Type) return Boolean
is (Size (Buffer) = 0);
function Full
(Buffer : in Ring_Buffer_Type) return Boolean
is (Size (Buffer) = Buffer.Max_Size);
function Size
(Buffer : in Ring_Buffer_Type) return Natural
is (Buffer.Count);
function Free
(Buffer : in Ring_Buffer_Type) return Natural
is (Buffer.Max_Size - Size (Buffer));
function First
(Buffer : in Ring_Buffer_Type) return Element_Type
is (Buffer.Items (Buffer.Head));
function Last
(Buffer : in Ring_Buffer_Type) return Element_Type
is (Buffer.Items (Buffer.Tail));
procedure Get
(Buffer : in out Ring_Buffer_Type;
Element : out Element_Type)
is
begin
Element := Buffer.Items (Buffer.Head);
Buffer :=
Buffer'Update
(Head =>
(if Buffer.Head = Buffer.Max_Size then 1 else Buffer.Head + 1),
Count => Buffer.Count - 1);
end Get;
procedure Put
(Buffer : in out Ring_Buffer_Type;
Element : in Element_Type)
is
begin
if Buffer.Tail = Buffer.Max_Size then
Buffer.Tail := 1;
else
Buffer.Tail := Buffer.Tail + 1;
end if;
Buffer.Items (Buffer.Tail) := Element;
Buffer.Count := Buffer.Count + 1;
end Put;
procedure Clear
(Buffer : in out Ring_Buffer_Type)
is
begin
Buffer.Head := 1;
Buffer.Tail := Buffer.Max_Size;
Buffer.Count := 0;
end Clear;
end Predicate8_Pkg;
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