W3C home > Mailing lists > Public > ietf-http-wg@w3.org > October to December 2013

Re: p6: maximum delta-seconds of 2147483648

From: Roy T. Fielding <fielding@gbiv.com>
Date: Fri, 15 Nov 2013 00:41:41 -0800
Cc: Willy Tarreau <w@1wt.eu>, "Julian F. Reschke" <julian.reschke@gmx.de>, Eliot Lear <lear@cisco.com>, HTTP Working Group <ietf-http-wg@w3.org>
Message-Id: <D5554410-4E14-425F-BBC9-DE2234F73D5E@gbiv.com>
To: Mark Nottingham <mnot@mnot.net>
This is what I am about to commit (and am happy to let Julian make any
tweaks later if more discussion calls for it) ...

1.2.1.  Delta Seconds

   The delta-seconds rule specifies a non-negative integer, representing
   time in seconds.

     delta-seconds  = 1*DIGIT

   A recipient parsing a delta-seconds value and converting it to binary
   form ought to use an arithmetic type of at least 31 bits of non-
   negative integer range.  If a cache receives a delta-seconds value
   greater than the greatest integer it can represent, or if any of its
   subsequent calculations overflows, the cache MUST consider the value
   to be either 2147483648 (2^31) or the greatest positive integer it can
   conveniently represent.

      Note: The value 2147483648 is here for historical reasons,
      effectively represents infinity (over 68 years), and does not need
      to be stored in binary form; an implementation could produce it as
      a canned string if any overflow occurs, even if the calculations
      are performed with an arithmetic type incapable of directly
      representing that number.  What matters here is that an overflow
      be detected and not treated as a negative value in later
      calculations.

Cool?

....Roy
Received on Friday, 15 November 2013 08:42:05 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 1 March 2016 11:11:19 UTC