ghosts alpha

lb_common.lua

@@ -124,3 +124,44 @@ rawset(_G, "lb_fire_event", function(event, ...)
 		pcall(callback, ...)
 	end
 end)
+
+local b62 = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+local function base62_encode(n)
+	if n <= 0 then return "0" end
+	local b62 = b62
+	local q = n
+	local r = ""
+	local t
+	while q > 0 do
+		t = q % 62 + 1
+		r = b62:sub(t, t)..r
+		q = q / 62
+	end
+	return r
+end
+
+local function base62_decode(s)
+	local n = b62:find(s:sub(1,1)) - 1
+	for i = 2, #s do
+		n = n * 62 + b62:find(s:sub(i, i)) - 1
+	end
+
+	return n
+end
+
+local function neg_base62_encode(n)
+	if n == INT32_MIN then
+		return "-2lkCB2"
+	end
+
+	if n < 0 then return "-"..base62_encode(abs(n)) end
+	return base62_encode(n)
+end
+
+local function neg_base62_decode(s)
+	if s:sub(1, 1) == "-" then return -base62_decode(s:sub(2)) end
+	return base62_decode(s)
+end
+
+rawset(_G, "lb_base62_encode", neg_base62_encode)
+rawset(_G, "lb_base62_decode", neg_base62_decode)