----------------------------------------------------------------------------
-- Decode an URL-encoded string (see RFC 2396)
----------------------------------------------------------------------------
function url_unescape (str)
	str = string.gsub (str, "+", " ")
	str = string.gsub (str, "%%(%x%x)", function(h) return string.char(tonumber(h,16)) end)
	str = string.gsub (str, "\r\n", "\n")
	return str
end

----------------------------------------------------------------------------
-- URL-encode a string (see RFC 2396)
----------------------------------------------------------------------------
function url_escape (str)
	str = string.gsub (str, "\n", "\r\n")
	str = string.gsub (str, "([^%w ])",
		function (c) return string.format ("%%%02X", string.byte(c)) end)
	str = string.gsub (str, " ", "+")
	return str
end