Revision: 5594
Author: [email protected]
Date: Wed Oct 6 01:33:52 2010
Log: During StringToDouble negative exponents may be less than -999 with a
result that is not 0.0.
Review URL: http://codereview.chromium.org/3564011
http://code.google.com/p/v8/source/detail?r=5594
Modified:
/branches/bleeding_edge/src/conversions.cc
/branches/bleeding_edge/test/cctest/test-conversions.cc
=======================================
--- /branches/bleeding_edge/src/conversions.cc Mon Sep 20 02:18:00 2010
+++ /branches/bleeding_edge/src/conversions.cc Wed Oct 6 01:33:52 2010
@@ -665,9 +665,15 @@
buffer[buffer_pos++] = '-';
exponent = -exponent;
}
- if (exponent > 999) exponent = 999; // Result will be Infinity or 0
or -0.
-
- const int exp_digits = 3;
+
+ // The minimal/maximal double is +/-1.7e-308. Given that
+ // the buffer contains at most 773 (kMaxSignificantDigits + 1) the
+ // minimal possible exponent is hence -(308 + 773)=-1081.
+ // Since leading zeros are removed the maximal exponent cannot exceed
308.
+ // If the following test triggers the result will be +/-infinity or
+/-0.
+ if (exponent > 9999) exponent = 9999;
+
+ const int exp_digits = 4;
for (int i = 0; i < exp_digits; i++) {
buffer[buffer_pos + exp_digits - 1 - i] = '0' + exponent % 10;
exponent /= 10;
=======================================
--- /branches/bleeding_edge/test/cctest/test-conversions.cc Thu Mar 25
07:39:39 2010
+++ /branches/bleeding_edge/test/cctest/test-conversions.cc Wed Oct 6
01:33:52 2010
@@ -167,6 +167,38 @@
CHECK_EQ(gay_strtod(num, NULL), StringToDouble(num, NO_FLAGS));
}
+
+TEST(MinimumExponent) {
+ // Same test but with different point-position.
+ char num[] =
+ "445014771701440202508199667279499186358524265859260511351695091"
+ "228726223124931264069530541271189424317838013700808305231545782"
+ "515453032382772695923684574304409936197089118747150815050941806"
+ "048037511737832041185193533879641611520514874130831632725201246"
+ "060231058690536206311752656217652146466431814205051640436322226"
+ "680064743260560117135282915796422274554896821334728738317548403"
+ "413978098469341510556195293821919814730032341053661708792231510"
+ "873354131880491105553390278848567812190177545006298062245710295"
+ "816371174594568773301103242116891776567137054973871082078224775"
+ "842509670618916870627821633352993761380751142008862499795052791"
+ "018709663463944015644907297315659352441231715398102212132212018"
+ "470035807616260163568645811358486831521563686919762403704226016"
+ "998291015625000000000000000000000000000000000e-1108";
+
+ CHECK_EQ(gay_strtod(num, NULL), StringToDouble(num, NO_FLAGS));
+
+ // Changes the result of strtod (at least in glibc implementation).
+ num[sizeof(num) - 8] = '1';
+
+ CHECK_EQ(gay_strtod(num, NULL), StringToDouble(num, NO_FLAGS));
+}
+
+
+TEST(MaximumExponent) {
+ char num[] = "0.16e309";
+
+ CHECK_EQ(gay_strtod(num, NULL), StringToDouble(num, NO_FLAGS));
+}
TEST(ExponentNumberStr) {
--
v8-dev mailing list
[email protected]
http://groups.google.com/group/v8-dev
