def self.binary?(file)
return false if file =~ /\.(rdoc|txt)$/
s = File.read(file, 1024) or return false
have_encoding = s.respond_to? :encoding
if have_encoding then
return false if s.encoding != Encoding::ASCII_8BIT and s.valid_encoding?
end
return true if s[0, 2] == Marshal.dump('')[0, 2] or s.index("\x00")
if have_encoding then
s.force_encoding Encoding.default_external
not s.valid_encoding?
else
if 0.respond_to? :fdiv then
s.count("\x00-\x7F", "^ -~\t\r\n").fdiv(s.size) > 0.3
else
(s.count("\x00-\x7F", "^ -~\t\r\n").to_f / s.size) > 0.3
end
end
end