diff --git a/tiny.lua b/tiny.lua
new file mode 100644
index 0000000..f06d37e
--- /dev/null
+++ b/tiny.lua
@@ -0,0 +1,83 @@
+local M = {};
+
+	local base_set= "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz_"
+
+	function M.set_base(value) 
+		base_set = value or base_set;
+	end
+
+	function M.tonumber(e,base)
+		base = base or 10;
+		if base == 10 then return  tonumber(e) end
+		if tonumber(e) ~= nil then return M.encode(e,base) end
+
+		return M.decode(e,base);
+	end
+
+	function M.encode(interger,base)
+		base = base or 62;
+		local key = base_set:sub(1,base);
+		local hexn,radix = "",key:len();
+		if base <=36 then key:lower();end
+		
+		repeat
+			local r = interger % radix;
+			interger = (interger - r) / radix
+			hexn = key:charAt(r) .. hexn;
+		until interger == 0
+		
+		return  hexn
+	end
+
+	function M.decode(string,base)
+		base = base or 62;
+		local key = base_set:sub(1,base);
+		local radix,strlen = key:len(),string:len();
+		if base <=36 then key:lower();string:lower() end
+
+		local n,i = 0,0;
+		while i < strlen do
+			local p = key:index(string:charAt(i));
+			if p < 0 then return -1 end
+			n =n + p * math.pow(radix, strlen - i - 1);
+			i = i+1;
+		end
+
+		return n;
+	end
+
+	function string.fromhex(self)
+	    return (self:gsub('..', function (cc)
+	        return string.char(tonumber(cc, 16))
+	    end))
+	end
+
+	function string.tohex(self)
+	    return (self:gsub('.', function (c)
+	        return string.format('%02X', string.byte(c))
+	    end))
+	end
+
+	-- index range [0,len-1]
+	function string.charAt(self,index)
+		return self:sub(index+1,index+1)
+	end
+
+	-- index range [-1,len-1]
+	-- -1 returned if not find.
+	function string.index(self,str)
+		local index,_ = self:find(str);
+		index = index or 0;
+		return index - 1
+	end
+
+	print(M.tonumber(2834438,2));
+	print(M.tonumber(2834438,8));
+	print(M.tonumber(2834438,16));
+	print(M.tonumber(2834438,33));
+	print(M.tonumber(2834438,61));
+
+	print(M.decode(M.encode(288,2),2));
+	print(M.decode(M.encode(288)))
+
+	return M;