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From: Laurent Bercot <ska-dietlibc@skarnet.org>
To: musl@lists.openwall.com
Subject: Re: [PATCHv2] Add support for leap seconds in zoneinfo files
Date: Thu, 05 Dec 2013 08:58:50 +0000	[thread overview]
Message-ID: <52A0404A.4050106@skarnet.org> (raw)
In-Reply-To: <20131205051809.GY1685@port70.net>


> i assume
>
> 	hit=leapsecs_sub(&t);
> 	if(hit) t++;
> 	leapsecs_add(&t,hit);

  This is true if and only if all leap seconds are 1, which is the case for now
and in the foreseeable future, but my version supports even the improbable
case where different corrections are introduced.
  But you are right, it is possible to go backwards too:

static void leapsecs_add(long long *t, int hit)
{
	long long trans;
	int corr;
	unsigned int i = __leapsecs_num;
	for (; i; i--) {
		__leapsecs_read(i-1, &trans, &corr);
		if (*t + corr >= trans) break ;
	}
	if (i) 	{
		*t += corr;
		if (hit && (t == trans)) {
			int oldcorr = 0;
			if (i > 1)
				__leapsecs_read(i-2, &trans, &oldcorr);
			*t += oldcorr - corr;
		}
	}
}

-- 
  Laurent



  reply	other threads:[~2013-12-05  8:58 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-26 18:53 [PATCH] " Laurent Bercot
2013-11-26 18:59 ` Laurent Bercot
2013-11-26 23:32 ` Rich Felker
2013-11-27  1:06   ` Rich Felker
2013-11-27  4:10   ` Laurent Bercot
2013-11-27  4:25     ` Rich Felker
2013-11-27  5:53       ` Laurent Bercot
2013-11-27 18:43         ` Szabolcs Nagy
2013-11-27 20:33           ` Laurent Bercot
2013-12-05  1:13             ` [PATCHv2] " Laurent Bercot
2013-12-05  5:18               ` Szabolcs Nagy
2013-12-05  8:58                 ` Laurent Bercot [this message]
2013-12-05 14:21                   ` Szabolcs Nagy
2013-12-05 14:43               ` Rich Felker
2013-12-05 16:31                 ` Laurent Bercot
2013-12-05 16:40                   ` Rich Felker
2013-12-06  0:36                     ` Laurent Bercot
2013-12-06  0:45                       ` Rich Felker
2013-12-06  1:15                         ` Laurent Bercot
2013-12-06  5:31                           ` Szabolcs Nagy
2013-12-06 10:48                             ` Laurent Bercot
2013-12-06 11:38                               ` Raphael Cohn
2013-12-06 23:29                                 ` Laurent Bercot
2013-12-07  2:31                                   ` Rich Felker
2013-12-07  4:02                                     ` Szabolcs Nagy
2013-12-07  8:52                                     ` Laurent Bercot
2013-12-06  6:29                           ` Rich Felker
2013-12-06 10:37                             ` Laurent Bercot
2013-12-06 12:50                               ` Rich Felker
2013-12-06 13:27                                 ` Szabolcs Nagy
2013-12-06 15:48                                   ` Rich Felker

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