MUC: occupant: refactor to allow storing more than just presence for a session Previously a "session" (i.e. a full JID joined to a MUC) was stored as simply a mapping of full JIDs->presence, contained within occupant objects (an occupant object groups all sessions behind a certain nick in the MUC). To enable developing GC3 and other features, it would be helpful if we can store additional metadata when a client joins a room, for example, whether it has opted out of receiving presence stanzas (a GC3 feature). This changes the internal data structure, which shouldn't be used outside this module, it adds a new :get_session() method, and modifies the :each_session() iterator to return the session as an additional result (which should be backwards compatible with code that just consumes the existing two results).

local s_char = string.char;
local s_format = string.format;
local s_gsub = string.gsub;
local s_lower = string.lower;

local char_to_hex = {};
local hex_to_char = {};

do
	local char, hex;
	for i = 0,255 do
		char, hex = s_char(i), s_format("%02x", i);
		char_to_hex[char] = hex;
		hex_to_char[hex] = char;
	end
end

local function to(s)
	return (s_gsub(s, ".", char_to_hex));
end

local function from(s)
	return (s_gsub(s_lower(s), "%X*(%x%x)%X*", hex_to_char));
end

return {
	encode = to, decode = from;
	-- COMPAT w/pre-0.12:
	to = to, from = from;
};