SDL Joystick GUID finder

get-joystick-guid

#!/usr/bin/env ruby

class JoystickGUID
	EVIOCGID = 0x80084502

	# Derive an SDL-style GUID from bus type, vendor, product, version
	def JoystickGUID::ReadGUID(filename)
		input = [0,0,0,0].pack('SSSS')	
		success = 0
		File.open(filename, File::RDONLY|File::NONBLOCK){ |file|
			success = file.ioctl(EVIOCGID, input)
		}
		bustype, vendor, product, version = input.unpack('SSSS')
		if(0 != success || 0 == vendor || 0 == product || 0 == version) then return nil end
		return format('%02x%02x0000%02x%02x0000%02x%02x0000%02x%02x0000', bustype & 0xFF, bustype >> 8,
										  vendor & 0xFF, vendor >> 8,
										  product & 0xFF, product >> 8,
										  version & 0xFF, version >> 8);
	end
end

if(__FILE__ == $0)
	if(1 != ARGV.length)
		puts("Usage: #{$0} path to device event")
		exit
	end

	puts("#{ARGV[0]}: #{JoystickGUID::ReadGUID(ARGV[0])}")
end

things appear to have changed since.. :)