Bug 91579 – Decimal constructor with 99999999999999999 loses last digit

• Status: RESOLVED
• Resolution: FIXED
• Component: Platform

There is a bug in Decimal::EncodedData constructor with maximum coefficient, 99999999999999999, in following line:


Decimal::EncodedData::EncodedData(Sign sign, int exponent, uint64_t coefficient)
{
  ...
    if (exponent >= ExponentMin && exponent <= ExponentMax) {
        while (coefficient >= MaxCoefficient) { // *** BUG, we should use ">" instead of ">=".
            coefficient /= 10;
            ++exponent;
        }
    }
  ...
}

Created attachment 152918 [details]
Patch 1

Comment on attachment 152918 [details]
Patch 1

Could you review this patch?
Thanks in advance.

[Kent Tamura]

Comment on attachment 152918 [details]
Patch 1

looks ok

Comment on attachment 152918 [details]
Patch 1

Clearing flags on attachment: 152918

Committed r122922: <http://trac.webkit.org/changeset/122922>

All reviewed patches have been landed.  Closing bug.

[Alexey Proskuryakov]

This is fixing Platform code. Is that code used anywhere? An actual regression test would be vastly preferable to a unit test (which is not even cross-platform!)

(In reply to comment #6)
> This is fixing Platform code. Is that code used anywhere? An actual regression test would be vastly preferable to a unit test (which is not even cross-platform!)

The code is used in step-able input types, number, date, range, datetime, and so on. Although, it is hard to hit this case from HTML5/JavaScript, because the value is out of range of double.

The purpose of fixing this is for test case (bug 91481) and that test case is supplement for LayoutTest.