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Diffstat (limited to 'tools/source/generic/rational.cxx')
| -rw-r--r-- | tools/source/generic/rational.cxx | 173 |
1 files changed, 0 insertions, 173 deletions
diff --git a/tools/source/generic/rational.cxx b/tools/source/generic/rational.cxx deleted file mode 100644 index 6222265b87f3..000000000000 --- a/tools/source/generic/rational.cxx +++ /dev/null @@ -1,173 +0,0 @@ -/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ -/* - * This file is part of the LibreOffice project. - * - * This Source Code Form is subject to the terms of the Mozilla Public - * License, v. 2.0. If a copy of the MPL was not distributed with this - * file, You can obtain one at http://mozilla.org/MPL/2.0/. - * - */ - -#include <tools/debug.hxx> -#include <tools/rational.hxx> -#include <tools/stream.hxx> - -// If dVal > LONG_MAX or dVal < LONG_MIN, the rational throws a boost::bad_rational. -// Otherwise, dVal and denominator are multiplied with 10, until one of them -// is larger than (LONG_MAX / 10). -boost::rational<long> rational_FromDouble(double dVal) -{ - long nDen = 1; - long nMAX = LONG_MAX / 10; - - if ( dVal > LONG_MAX || dVal < LONG_MIN ) - { - throw boost::bad_rational(); - } - - while ( std::abs( (long)dVal ) < nMAX && nDen < nMAX ) - { - dVal *= 10; - nDen *= 10; - } - return boost::rational<long>((long) dVal, nDen); -} - -// Similar to clz_table that can be googled -const char nbits_table[32] = -{ - 32, 1, 23, 2, 29, 24, 14, 3, - 30, 27, 25, 18, 20, 15, 10, 4, - 31, 22, 28, 13, 26, 17, 19, 9, - 21, 12, 16, 8, 11, 7, 6, 5 -}; - -static int impl_NumberOfBits( unsigned long nNum ) -{ - // http://en.wikipedia.org/wiki/De_Bruijn_sequence - // background paper: Using de Bruijn Sequences to Index a 1 in a - // Computer Word (1998) Charles E. Leiserson, - // Harald Prokop, Keith H. Randall - // (e.g. http://citeseer.ist.psu.edu/leiserson98using.html) - const sal_uInt32 nDeBruijn = 0x7DCD629; - - if ( nNum == 0 ) - return 0; - - // Get it to form like 0000001111111111b - nNum |= ( nNum >> 1 ); - nNum |= ( nNum >> 2 ); - nNum |= ( nNum >> 4 ); - nNum |= ( nNum >> 8 ); - nNum |= ( nNum >> 16 ); - - sal_uInt32 nNumber; - int nBonus = 0; - -#if SAL_TYPES_SIZEOFLONG == 4 - nNumber = nNum; -#elif SAL_TYPES_SIZEOFLONG == 8 - nNum |= ( nNum >> 32 ); - - if ( nNum & 0x80000000 ) - { - nNumber = sal_uInt32( nNum >> 32 ); - nBonus = 32; - - if ( nNumber == 0 ) - return 32; - } - else - nNumber = sal_uInt32( nNum & 0xFFFFFFFF ); -#else -#error "Unknown size of long!" -#endif - - // De facto shift left of nDeBruijn using multiplication (nNumber - // is all ones from topmost bit, thus nDeBruijn + (nDeBruijn * - // nNumber) => nDeBruijn * (nNumber+1) clears all those bits to - // zero, sets the next bit to one, and thus effectively shift-left - // nDeBruijn by lg2(nNumber+1). This generates a distinct 5bit - // sequence in the msb for each distinct position of the last - // leading 0 bit - that's the property of a de Bruijn number. - nNumber = nDeBruijn + ( nDeBruijn * nNumber ); - - // 5-bit window indexes the result - return ( nbits_table[nNumber >> 27] ) + nBonus; -} - -/** Inaccurate cancellation for a fraction. - - Clip both nominator and denominator to said number of bits. If - either of those already have equal or less number of bits used, - this method does nothing. - - @param nSignificantBits denotes, how many significant binary - digits to maintain, in both nominator and denominator. - - @example ReduceInaccurate(8) has an error <1% [1/2^(8-1)] - the - largest error occurs with the following pair of values: - - binary 1000000011111111111111111111111b/1000000000000000000000000000000b - = 1082130431/1073741824 - = approx. 1.007812499 - - A ReduceInaccurate(8) yields 1/1. -*/ -void rational_ReduceInaccurate(boost::rational<long>& rRational, unsigned nSignificantBits) -{ - if ( !rRational.numerator() || !rRational.denominator() ) - return; - - // Count with unsigned longs only - // http://www.boost.org/doc/libs/release/libs/rational/rational.html#Internal%20representation - const bool bNeg = ( rRational.numerator() < 0 ); - unsigned long nMul = (unsigned long)( bNeg? -rRational.numerator(): rRational.numerator() ); - unsigned long nDiv = (unsigned long)( rRational.denominator() ); - - DBG_ASSERT(nSignificantBits<65, "More than 64 bit of significance is overkill!"); - - // How much bits can we lose? - const int nMulBitsToLose = impl_NumberOfBits( nMul ) - int( nSignificantBits ); - const int nDivBitsToLose = impl_NumberOfBits( nDiv ) - int( nSignificantBits ); - - int nToLose = nMulBitsToLose < nDivBitsToLose ? nMulBitsToLose : nDivBitsToLose; - nToLose = nToLose < 0 ? 0 : nToLose; - - // Remove the bits - nMul >>= nToLose; - nDiv >>= nToLose; - - if ( !nMul || !nDiv ) - { - // Return without reduction - OSL_FAIL( "Oops, we reduced too much..." ); - return; - } - - rRational.assign( bNeg? -long( nMul ): long( nMul ), nDiv ); -} - -SvStream& ReadFraction(SvStream& rIStream, boost::rational<long>& rRational) -{ - sal_Int32 nTmpNumerator(0), nTmpDenominator(0); - rIStream.ReadInt32( nTmpNumerator ); - rIStream.ReadInt32( nTmpDenominator ); - // NOTE: use rational zero for invalid rationals - avoid boost::bad_rational() exception - if (nTmpDenominator == 0) { - nTmpNumerator = 0; - nTmpDenominator = 1; - } - rRational.assign( nTmpNumerator, nTmpDenominator ); - return rIStream; -} - -SvStream& WriteFraction(SvStream& rOStream, const boost::rational<long>& rRational) -{ - //fdo#39428 SvStream no longer supports operator<<(long) - rOStream.WriteInt32( sal::static_int_cast<sal_Int32>(rRational.numerator()) ); - rOStream.WriteInt32( sal::static_int_cast<sal_Int32>(rRational.denominator()) ); - return rOStream; -} - -/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |