diff options
Diffstat (limited to 'tools')
-rw-r--r-- | tools/source/generic/fract.cxx | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/tools/source/generic/fract.cxx b/tools/source/generic/fract.cxx index 7f2ffba1003d..b6ae743764df 100644 --- a/tools/source/generic/fract.cxx +++ b/tools/source/generic/fract.cxx @@ -483,4 +483,44 @@ size_t Fraction::GetHashValue() const return hash; } +Fraction Fraction::MakeFraction( tools::Long nN1, tools::Long nN2, tools::Long nD1, tools::Long nD2 ) +{ + if( nD1 == 0 || nD2 == 0 ) //under these bad circumstances the following while loop will be endless + { + SAL_WARN("tools.fraction", "Invalid parameter for ImplMakeFraction"); + return Fraction( 1, 1 ); + } + + tools::Long i = 1; + + if ( nN1 < 0 ) { i = -i; nN1 = -nN1; } + if ( nN2 < 0 ) { i = -i; nN2 = -nN2; } + if ( nD1 < 0 ) { i = -i; nD1 = -nD1; } + if ( nD2 < 0 ) { i = -i; nD2 = -nD2; } + // all positive; i sign + + boost::rational<sal_Int32> a = toRational(i*nN1, nD1); + boost::rational<sal_Int32> b = toRational(nN2, nD2); + bool bFail = checked_multiply_by(a, b); + + + while ( bFail ) { + if ( nN1 > nN2 ) + nN1 = (nN1 + 1) / 2; + else + nN2 = (nN2 + 1) / 2; + if ( nD1 > nD2 ) + nD1 = (nD1 + 1) / 2; + else + nD2 = (nD2 + 1) / 2; + + a = toRational(i*nN1, nD1); + b = toRational(nN2, nD2); + bFail = checked_multiply_by(a, b); + } + + rational_ReduceInaccurate(a, /*nSignificantBits*/32); + return Fraction(a.numerator(), a.denominator()); +} + /* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |