Understanding a counter

I want to understand this code. Can anyone tell help me, how does it work?

library IEEE;

use IEEE.STD_LOGIC_1164.ALL;

use ieee.numeric_std.all;

use ieee.std_logic_arith.all;-- Uncomment the following library declaration if using-- arithmetic functions with Signed or Unsigned values--use

IEEE.NUMERIC_STD.ALL;-- Uncomment the following library declaration if instantiating-- any Xilinx primitives in this code.--library UNISIM;--use UNISIM.VComponents.all;

entity leds2_8 is

GENERIC (n: positive := 2**22);

Port ( clkin : in STD_LOGIC;

clkout : out STD_LOGIC;

leds : out STD_LOGIC_VECTOR (7 downto 0));

end leds2_8;

architecture Behavioral of leds2_8 is

begin

PROCESS (clkin)

VARIABLE count: INTEGER RANGE 0 to n;

variable counter : integer range 0 to 255;

BEGIN

IF(clkin'EVENT AND clkin='1') THEN

count :=count + 1;

IF(count=n/2) THEN

clkout <='1';

ELSIF (count=n) THEN

clkout <='0';

count :=0;

counter :=counter+1;

leds <=conv_std_logic_vector(counter,8);

END IF;

END IF;

END PROCESS;

end Behavioral;