From: Jakub Jelinek <jakub@redhat.com>
To: Ulrich Drepper <drepper@redhat.com>
Cc: Glibc hackers <libc-hacker@sources.redhat.com>
Subject: [PATCH] Fix BZ#4070 special case
Date: Fri, 13 Apr 2007 14:20:00 -0000 [thread overview]
Message-ID: <20070413142401.GG1826@sunsite.mff.cuni.cz> (raw)
Hi!
When !info->alt, trailing zeros are removed and decimal point as well.
So for a number which has exponent -5 initially, but rounds to
0.0001, we have L"1.0000..." at wstartp and wcp == wstartp + 1
(as even the decimal point was eaten). This results either in an assertion
failure or with -DNDEBUG=1 in wmemset with -1L as last argument (thus likely
a segfault).
2007-04-13 Jakub Jelinek <jakub@redhat.com>
* stdio-common/printf_fp.c (___printf_fp): Fix exponent -4
special case handling when wcp == wstartp + 1. Fix a comment typo.
* stdio-common/tfformat.c (sprint_doubles): Add a new testcase.
--- libc/stdio-common/printf_fp.c.jj 2007-02-26 18:13:47.000000000 +0100
+++ libc/stdio-common/printf_fp.c 2007-04-13 16:03:38.000000000 +0200
@@ -990,7 +990,7 @@ ___printf_fp (FILE *fp,
0))
/* This is a special case: the rounded number is 1.0,
the format is 'g' or 'G', and the alternative format
- is selected. This means the result mist be "1.". */
+ is selected. This means the result must be "1.". */
--added_zeros;
}
@@ -1081,12 +1081,17 @@ ___printf_fp (FILE *fp,
/* This is another special case. The exponent of the number is
really smaller than -4, which requires the 'e'/'E' format.
But after rounding the number has an exponent of -4. */
- assert (wcp >= wstartp + 2);
+ assert (wcp >= wstartp + 1);
assert (wstartp[0] == L'1');
__wmemcpy (wstartp, L"0.0001", 6);
wstartp[1] = decimalwc;
- wmemset (wstartp + 6, L'0', wcp - (wstartp + 2));
- wcp += 4;
+ if (wcp >= wstartp + 2)
+ {
+ wmemset (wstartp + 6, L'0', wcp - (wstartp + 2));
+ wcp += 4;
+ }
+ else
+ wcp += 5;
}
else
{
--- libc/stdio-common/tfformat.c.jj 2007-02-26 18:13:47.000000000 +0100
+++ libc/stdio-common/tfformat.c 2007-04-13 15:52:53.000000000 +0200
@@ -4020,6 +4020,7 @@ sprint_double_type sprint_doubles[] =
{__LINE__, 0.000956, "0.001", "%#.0g"},
{__LINE__, 0.000098, "0.0001", "%#.0g"},
{__LINE__, 0.0000996, "0.00010", "%#.2g"},
+ {__LINE__, 9.999999999999999e-05, "0.0001", "%g"},
{0 }
Jakub
reply other threads:[~2007-04-13 14:20 UTC|newest]
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