Packets: Fix VariantParser invalid parser access bug

[senf.git] / Utils / IpChecksum.hh

diff --git a/Utils/IpChecksum.hh b/Utils/IpChecksum.hh
index 7efb55d..a8ea1ff 100644 (file)
--- a/Utils/IpChecksum.hh
+++ b/Utils/IpChecksum.hh
@@ -1,8 +1,8 @@
 // $Id$
 //
-// Copyright (C) 2007 
-// Fraunhofer Institut fuer offene Kommunikationssysteme (FOKUS)
-// Kompetenzzentrum fuer Satelitenkommunikation (SatCom)
+// Copyright (C) 2007
+// Fraunhofer Institute for Open Communication Systems (FOKUS)
+// Competence Center NETwork research (NET), St. Augustin, GERMANY
 //     Stefan Bund <g0dil@berlios.de>
 //
 // This program is free software; you can redistribute it and/or modify
@@ -23,8 +23,8 @@
 /** \file
     \brief IpChecksum public header */
 
-#ifndef HH_IpChecksum_
-#define HH_IpChecksum_ 1
+#ifndef HH_SENF_Utils_IpChecksum_
+#define HH_SENF_Utils_IpChecksum_ 1
 
 // Custom includes
 #include <boost/cstdint.hpp>
@@ -34,7 +34,17 @@
 
 namespace senf {
     
-    /** \brief
+    /** \brief Calculate TCP/IP 16bit checksum value
+
+        This class allows calculation of the 16bit checksum value as defined in the TCP/IP v4
+        RFC's. This checksum is \e not a CRC.
+
+        To calculate the checksum, you create an instance of IpChecksum. You then repeatedly call
+        the feed() members to pass data in. After all data has been processed, the sum() member will
+        return the calculated checksum.
+
+        The mathematical properties of the checksum allow to skip any \e even number of zero bytes
+        without changing the checksum value.
       */
     class IpChecksum
     {
@@ -51,12 +61,13 @@ namespace senf {
         ///@}
         ///////////////////////////////////////////////////////////////////////////
 
-        void feed(boost::uint8_t byte);
+        void feed(boost::uint8_t byte); ///< Feed single byte
 
         template <class InputIterator>
         void feed(InputIterator b, InputIterator e);
+                                        ///< Feed range of bytes
 
-        boost::uint16_t sum() const;
+        boost::uint16_t sum() const;    ///< Calculate checksum
     
     protected: