Raise an error if length is longer than 9 digits

lib/otnetstring.rb

@@ -1,14 +1,22 @@
 require 'stringio'
 
 module OTNetstring
+  class Error < StandardError; end
+
   def self.parse(io)
     io = StringIO.new(io) if io.respond_to? :to_str
-    length, byte = "", "0"
-    while byte =~ /\d/
-      length << byte
+    length, byte = "", nil
+
+    while byte.nil? || byte =~ /\d/
+      length << byte if byte
       byte = io.readchar
     end
-    length = length.to_i
+
+    if length.size > 9
+      raise Error, "#{length} is longer than 9 digits"
+    end
+    length = Integer(length)
+
     case byte
     when '#' then Integer io.read(length)
     when ',' then io.read(length)

spec/otnetstring_spec.rb

@@ -59,6 +59,12 @@
     it "parses a boolean" do
       OTNetstring.parse('4!true!').should == true
     end
+
+    it "raises an error if length is longer than 9 digits" do
+      lambda {
+        OTNetstring.parse('9' * 10 + ',')
+      }.should raise_error(OTNetstring::Error, '9999999999 is longer than 9 digits')
+    end
   end
 
   context "encoding" do