Re: Date parsing

From: Stephan Beyer <s-beyer@gmx.net>
Date: Jun 21, 2008, 21:52 UTC
Message-ID: <20080621215240.GD15111@leksak.fem-net>
In-Reply-To: <alpine.LFD.1.10.0806100942500.3101@woody.linux-foundation.org>

Hi,

Show 11 quoted lines

> > On Tue, Jun 10, 2008 at 5:10 PM, Brandon Casey <casey@nrlssc.navy.mil> wrote:
> > > Take a look at match_multi_number in date.c
> > > European ordering is preferred when the separator is '.'
> > 
> > Ok, then I'll use . in the future, that's nice :).
> 
> Well, there are safer ways to give the date.
> 
> If you do it in strict rfc822 format, you'll never have any confusion 
> what-so-ever. The "approxidate()" thing tries to parse any random input, 
> but it *is* meant to be excessively liberal.

Today I've been playing around with approxidate(), too, and I think I found some bug in date parsing. I let copy&paste speak...

Correct:

$ ./test-date "2008-07-01 23:59:59 +0200" 2008-07-01 23:59:59 +0200 -> 1214949599 +0200 -> Tue Jul 1 23:59:59 2008 2008-07-01 23:59:59 +0200 -> Tue Jul 1 23:59:59 2008

And even:

$ ./test-date "2008-07-01 24:00:00 +0200" 2008-07-01 24:00:00 +0200 -> 1214949600 +0200 -> Wed Jul 2 00:00:00 2008 2008-07-01 24:00:00 +0200 -> Wed Jul 2 00:00:00 2008

But then there's a jump in time:

$ ./test-date "2008-07-02 00:00:00 +0200" 2008-07-02 00:00:00 +0200 -> 1202335200 +0200 -> Wed Feb 6 23:00:00 2008 2008-07-02 00:00:00 +0200 -> Wed Feb 6 23:00:00 2008

$ ./test-date "2008-07-02 01:00:00 +0200" 2008-07-02 01:00:00 +0200 -> 1202338800 +0200 -> Thu Feb 7 00:00:00 2008 2008-07-02 01:00:00 +0200 -> Thu Feb 7 00:00:00 2008

If we let test-date just print the timestamp...

diff --git a/test-date.c b/test-date.c
index 62e8f23..18d53c1 100644
--- a/test-date.c
+++ b/test-date.c
@@ -11,10 +11,10 @@ int main(int argc, char **argv)
 		memcpy(result, "bad", 4);
 		parse_date(argv[i], result, sizeof(result));
 		t = strtoul(result, NULL, 0);
-		printf("%s -> %s -> %s", argv[i], result, ctime(&t));
+		printf("%s -> %lu\n", argv[i], t);
 
 		t = approxidate(argv[i]);
-		printf("%s -> %s\n", argv[i], ctime(&t));
+		printf("%s -> %lu\n", argv[i], t);
 	}
 	return 0;
 }
-- -- -- --

... then we get:

$ ./test-date "2008-07-01 23:59:59 +0200"
2008-07-01 23:59:59 +0200 -> 1214949599
2008-07-01 23:59:59 +0200 -> 1214949599

$ ./test-date "2008-07-02 00:00:00 +0200"
2008-07-02 00:00:00 +0200 -> 1202335200
2008-07-02 00:00:00 +0200 -> 1202335200

Also, with another timezone, we get:

$ ./test-date "2008-07-01 23:59:59 +0000"
2008-07-01 23:59:59 +0000 -> 1214956799
2008-07-01 23:59:59 +0000 -> 1214956799

$ ./test-date "2008-07-02 00:00:00 +0000"
2008-07-02 00:00:00 +0000 -> 1202342400
2008-07-02 00:00:00 +0000 -> 1202342400

Is something wrong in my format or is there a bug?

Providing timestamps works, of course ;-)

Regards,
  Stephan

-- 
Stephan Beyer <s-beyer@gmx.net>, PGP 0x6EDDD207FCC5040F