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authorSzabolcs Nagy <nsz@port70.net>2016-09-04 04:51:03 +0200
committerRich Felker <dalias@aerifal.cx>2016-10-20 13:29:34 -0400
commit6ffdc4579ffb34f4aab69ab4c081badabc7c0a9a (patch)
tree1ad511f097d1d0d999b2f9377b5027c99886ef7d /src
parentd184a09e0529f33d8ddddb8825039133483a2c41 (diff)
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fix strtod int optimization in non-nearest rounding mode
the mid-sized integer optimization relies on lnz set up properly
to mark the last non-zero decimal digit, but this was not done
if the non-zero digit lied outside the KMAX digits of the base
10^9 number representation.

so if the fractional part was a very long list of zeros (>2048*9 on
x86) followed by non-zero digits then the integer optimization could
kick in discarding the tiny non-zero fraction which can mean wrong
result on non-nearest rounding mode.

strtof, strtod and strtold were all affected.
Diffstat (limited to 'src')
-rw-r--r--src/internal/floatscan.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/src/internal/floatscan.c b/src/internal/floatscan.c
index 80305ee6..ae098526 100644
--- a/src/internal/floatscan.c
+++ b/src/internal/floatscan.c
@@ -110,7 +110,10 @@ static long double decfloat(FILE *f, int c, int bits, int emin, int sign, int po
 			gotdig=1;
 		} else {
 			dc++;
-			if (c!='0') x[KMAX-4] |= 1;
+			if (c!='0') {
+				lnz = dc;
+				x[KMAX-4] |= 1;
+			}
 		}
 	}
 	if (!gotrad) lrp=dc;