Outlook 2002 vs. Cyrus 2.1.12

[Thomas Fritz]

On Mon, 2003-02-10 at 20:52, Lawrence Greenfield wrote:
>    From: Fritz Test <Fritz.Test at bam.de>
>    Date: 09 Feb 2003 11:25:37 +0100
> [...]
>    With help of the analysis of Jeremy (Thanks) I patched the function
>    mkgmtime, such that it works for me now. The problem is, that gmtime(&t)
>    returns a null pointer for my 64-bit system if t is out of some range. I
>    don't know exactly what range, but I assume that the generated value for
>    the year must fit in 32 bits?.
> 
> Your patch wouldn't work on a system with an unsigned 64-bit time_t.
> (The median value would start out very large, and the binary search
> would never subtract enough to get down into "normal" time.)
> 
> It seems to me that moving 
>      if (bits > 40) { bits = 40; }
> 
> to above the
> 
>      t = (t < 0) ? 0 : ((time_t) 1 << bits);
> 
> would fix the problem.
> 
> Is my analysis correct?

Please correct me, but I think that the median is calculated here to be
the time_t value which translates to 1970-01-01 00:00:00 GMT. If we
modify 'bits' before caculating the median, we don't start the binary
search with this median value.
 
Unfortunately, I do not have a platform with unsigned time_t, so I
cannot test. Which systems have unsigned time_t?

Tom

> 
> Larry
> 
>    Here's a snipped of my code in mkgmtime.c
> 
>    -----------------------------------------------
> 
>      /*
>      ** If time_t is signed, then 0 is the median value,
>      ** if time_t is unsigned, then 1 << bits is median.
>      */
>      t = (t < 0) ? 0 : ((time_t) 1 << bits)
> 	;
> 
>      /* Patch begin */
>      /* 
>      ** On my 32-bit Debian GNU/Linux 3.0 AMD K6 PC, the algorithm
>      ** converges in a range 
>      ** from
>      **              1901-12-13 20:46:00 GMT -> -2147483640
>      ** to 
>      **              2038-01-19 03:14:07 GMT ->  2147483647 
>      */
> 
>      /* 
>      ** It segfaults on RedHat 7.2/Alpha if bits > 56, since gmtime (&t) 
>      ** returns null pointer.
>      ** Hence, set bits to a resonable value <= 56.
>      **
>      ** Setting, e.g. bits=40, the algorithm converges in a range 
>      ** from
>      **            -32873-11-12 23:24:00 GMT -> -1099511627760
>      ** to 
>      **             36812-02-20 00:36:59 GMT ->  1099511627819
>      */
>      if (bits > 40) {
>        bits = 40;
>      }
>      /* patch end */
> 
>      for ( ; ; ) {
> 
>        prt (t);
>        fprintf (stderr, " ");
> 
> 
>