RE: nonstandard assumptions in the code

["Howard Chu" <hyc@highlandsun.com>]

> -----Original Message-----
> From: Hallvard B Furuseth [mailto:h.b.furuseth@usit.uio.no]

> Kurt D. Zeilenga writes:
> >At 11:01 AM 5/30/2003, Hallvard B Furuseth wrote:
> >>
> >> Here are the nonstandard assumptions I have found.
> >> (...)
> 
> 
> >> * no padding bits in 'unsigned int'
> >>   (required by back-bdb/dbcache.c:bdb_db_hash() - don't know why)
> >> (...)
> > These should be fixed.
> 
> Howard, this is your code, from when you fixed ITS#1726.  Something
> about endianness, perhaps?  If not, we can use this function body,
> roughly from my original patch.  I have dropped the ugly if-test for
> whether or not memcpy can be used, since I doubt the code is 
> that time-
> critical.
> 
> {
> 	u_int32_t i, ret = 0;
> 
> 	if ( length > sizeof(u_int32_t) )
> 		length = sizeof(u_int32_t);
> 
> 	for( i = 0; i < length; i++ )
> 		ret = (ret << 8) + ((const unsigned char *)bytes)[i];
> 	return ret;
> }

I guess that's OK. Endianness shouldn't really be a problem here since
it's a hash, we don't care about the particular sort order.
> 
> >> * can cast function pointers to 'void *' and back
> >>   (at least the threading stuff)

K&R 2nd Edition (ANSI C) p.120 "Any pointer can be cast to void * and back
again without loss of information."

> Another non-ANSI thing: LBER_OPT_ON and LDAP_OPT_ON are #defined as
> ((void*)1).  There is no guarantee that this is != NULL (the *_OPT_OFF
> options).  I'll install this fix unless someone protests:

K&R 2nd Edition p.102 - NULL is zero, by definition. Also stated again
in section 6.2.2.3 of the C90 spec.

  -- Howard Chu
  Chief Architect, Symas Corp.       Director, Highland Sun
  http://www.symas.com               http://highlandsun.com/hyc
  Symas: Premier OpenSource Development and Support