diff options
| -rw-r--r-- | sc/source/core/tool/interpr2.cxx | 49 |
1 files changed, 42 insertions, 7 deletions
diff --git a/sc/source/core/tool/interpr2.cxx b/sc/source/core/tool/interpr2.cxx index 58b3008319ca..cf4dde09338c 100644 --- a/sc/source/core/tool/interpr2.cxx +++ b/sc/source/core/tool/interpr2.cxx @@ -963,20 +963,55 @@ void ScInterpreter::RoundNumber( rtl_math_RoundingMode eMode ) fVal = ::rtl::math::round( GetDouble(), 0, eMode ); else { - sal_Int16 nDec = GetInt16(); - double fX = GetDouble(); + const sal_Int16 nDec = GetInt16(); + const double fX = GetDouble(); if (nGlobalError == FormulaError::NONE) { + // A quite aggressive approach with 12 significant digits. + // However, using 14 or some other doesn't work because other + // values may fail, like =ROUNDDOWN(2-5E-015;13) would produce + // 2 (another example in tdf#124286). + constexpr sal_Int16 kSigDig = 12; + if ( ( eMode == rtl_math_RoundingMode_Down || eMode == rtl_math_RoundingMode_Up ) && - nDec < 12 && fmod( fX, 1.0 ) != 0.0 ) + nDec < kSigDig && fmod( fX, 1.0 ) != 0.0 ) + { - // tdf124286 : round to 12 significant digits before rounding + // tdf124286 : round to significant digits before rounding // down or up to avoid unexpected rounding errors // caused by decimal -> binary -> decimal conversion - double fRes; - RoundSignificant( fX, 12, fRes ); - fVal = ::rtl::math::round( fRes, nDec, eMode ); + + double fRes = fX; + // Similar to RoundSignificant() but omitting the back-scaling + // and interim integer rounding before the final rounding, + // which would result in double rounding. Instead, adjust the + // decimals and round into integer part before scaling back. + const double fTemp = floor( log10( std::abs(fRes))) + 1.0 - kSigDig; + // Avoid inaccuracy of negative powers of 10. + if (fTemp < 0.0) + fRes *= pow(10.0, -fTemp); + else + fRes /= pow(10.0, fTemp); + if (std::isfinite(fRes)) + { + // fRes is now at a decimal normalized scale. + // Truncate up-rounding to opposite direction for values + // like 0.0600000000000005 =ROUNDUP(8.06-8;2) that here now + // is 600000000000.005 and otherwise would yield 0.07 + if (eMode == rtl_math_RoundingMode_Up) + fRes = ::rtl::math::approxFloor(fRes); + fVal = ::rtl::math::round( fRes, nDec + fTemp, eMode ); + if (fTemp < 0.0) + fVal /= pow(10.0, -fTemp); + else + fVal *= pow(10.0, fTemp); + } + else + { + // Overflow. Let our round() decide if and how to round. + fVal = ::rtl::math::round( fX, nDec, eMode ); + } } else fVal = ::rtl::math::round( fX, nDec, eMode ); |