def slice(str, *args)
if args.size > 2
raise ArgumentError, "wrong number of arguments (#{args.size} for 1)"
elsif (args.size == 2 && !(args.first.is_a?(Numeric) || args.first.is_a?(Regexp)))
raise TypeError, "cannot convert #{args.first.class} into Integer"
elsif (args.size == 2 && !args[1].is_a?(Numeric))
raise TypeError, "cannot convert #{args[1].class} into Integer"
elsif args[0].kind_of? Range
cps = u_unpack(str).slice(*args)
cps.nil? ? nil : cps.pack('U*')
elsif args[0].kind_of? Regexp
str.slice(*args)
elsif args.size == 1 && args[0].kind_of?(Numeric)
u_unpack(str)[args[0]]
else
u_unpack(str).slice(*args).pack('U*')
end
end