voicechat.lua

returns `fn` which memoizes its arguments
local function memoize( fn )
	local cache = {}
	local function memoize(...)
		-- convert args into a string if they're a table
		local args = {...}
		local sArg = table.ToString(args)

		-- get the item with the given arguments from the cache
		local cached = cache[sArg]
		if cached == nil then
			-- if it doesn't exist, store it then return it
			local res = fn(...)
			cache[sArg] = res
			return res
		else
			-- otherwise return the value from the cache
			return cached
		end
	end
	return memoize
end

-- can listener hear talker?
local function playerCanHearPlayersVoice( listener, talker )
	return talker:Team() ~= TEAM_HIDDEN and talker:Alive()
end

-- memoize the can hear function and rememoize it each second
-- to essentially rebuild the can hear cache
local cached = memoize(playerCanHearPlayersVoice)
timer.Create("ClearVoiceCache", 1, 0, function()
	cached = memoize(playerCanHearPlayersVoice) 
end )

-- hook the cached function. This hook is called hundreds times
-- a second so the results need to be cached
hook.Add( "PlayerCanHearPlayersVoice", "VoiceCache", function(...) 
	return cached(...) 
end )