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bug#12350: Composites identified as primes in factor.c (when HAVE_GMP)
From: |
Jim Meyering |
Subject: |
bug#12350: Composites identified as primes in factor.c (when HAVE_GMP) |
Date: |
Thu, 06 Sep 2012 22:23:42 +0200 |
Torbjorn Granlund wrote:
> I and Niels now would appreciate feedback on the new factor code.
>
> We've put the entire little project in a tar file, which is attached.
> The code is also available at <http://gmplib.org:8000/factoring/>.
Thanks a lot! I've started looking at the code.
I was surprised to see "make check" fail.
$ ./ourseq 0 100000 > k
:
$ ./factor < k
:
0:
1:
2: 2
3: 3
4: 2 2
5: 5
6: 2 3
7: 7
8: 2 2 2
9: 3 3
zsh: abort (core dumped) ./factor < k
That was due to unexpected input.
Poking around, I see that ourseq writes from uninitialized memory:
$ ./ourseq 9 11
9
102
112
$ ./ourseq 9 11
9
10>
11>
$ ./ourseq 9 11
9
10"
11"
The fix is to change the memmove to copy one more byte each time:
to copy the required trailing NUL.
With that, it looks like "make check" will pass.
It will definitely benefit from running the individual
tests in parallel ;-)
>From 9e6db73344f43e828b8d716a0ea6a5842980d518 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Thu, 6 Sep 2012 22:12:41 +0200
Subject: [PATCH] incr: don't omit trailing NUL when incrementing
---
ourseq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/ourseq.c b/ourseq.c
index d2472aa..cb71f13 100644
--- a/ourseq.c
+++ b/ourseq.c
@@ -48,7 +48,7 @@ incr (string *st)
}
s[i] = '0';
}
- memmove (s + 1, s, len);
+ memmove (s + 1, s, len + 1);
s[0] = '1';
st->len = len + 1;
}
--
1.7.12.176.g3fc0e4c
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), (continued)
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Pádraig Brady, 2012/09/04
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Jim Meyering, 2012/09/04
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Eric Blake, 2012/09/04
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Jim Meyering, 2012/09/05
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Torbjorn Granlund, 2012/09/04
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Jim Meyering, 2012/09/05
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Torbjorn Granlund, 2012/09/06
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP),
Jim Meyering <=
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Torbjorn Granlund, 2012/09/06
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Torbjorn Granlund, 2012/09/06
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Jim Meyering, 2012/09/06
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Torbjorn Granlund, 2012/09/06
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Jim Meyering, 2012/09/07
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Torbjorn Granlund, 2012/09/07
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Torbjorn Granlund, 2012/09/07
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Torbjorn Granlund, 2012/09/13
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Jim Meyering, 2012/09/13
- bug#12350: Composites identified as primes in factor.c (when HAVE_GMP), Jim Meyering, 2012/09/13