add Address::IsInvalid

src/node/address.cc

@@ -40,6 +40,12 @@ Address::operator = (const Address &address)
   return *this;
 }
 
+bool
+Address::IsInvalid (void) const
+{
+  return m_len == 0 && m_type == 0;
+}
+
 uint8_t 
 Address::GetLength (void) const
 {

src/node/address.h

@@ -86,6 +86,14 @@ public:
   Address (const Address & address);
   Address &operator = (const Address &address);
 
+  /**
+   * \returns true if this address is invalid, false otherwise.
+   *
+   * An address is invalid if and only if it was created
+   * through the default constructor and it was never
+   * re-initialized.
+   */
+  bool IsInvalid (void);
   /**
    * \returns the length of the underlying address.
    */