Clean up some stuff, including a few spots where exceptions were not being handled correctly.

node/Buffer.hpp

@@ -301,6 +301,25 @@ public:
 		append(b._b,b._l);
 	}
 
+	/**
+	 * Increment size and return pointer to field of specified size
+	 *
+	 * The memory isn't actually written, so this is a shortcut for a multi-step
+	 * process involving getting the current pointer and adding size.
+	 *
+	 * @param l Length of field to append
+	 * @return Pointer to beginning of appended field of length 'l'
+	 */
+	inline char *appendField(unsigned int l)
+		throw(std::out_of_range)
+	{
+		if ((_l + l) > C)
+			throw std::out_of_range("Buffer: append beyond capacity");
+		char *r = _b + _l;
+		_l += l;
+		return r;
+	}
+
 	/**
 	 * Increment size by a given number of bytes
 	 *