Line data    Source code

       1             : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
       2             : /*
       3             :  * This file is part of the LibreOffice project.
       4             :  *
       5             :  * This Source Code Form is subject to the terms of the Mozilla Public
       6             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       7             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
       8             :  *
       9             :  * This file incorporates work covered by the following license notice:
      10             :  *
      11             :  *   Licensed to the Apache Software Foundation (ASF) under one or more
      12             :  *   contributor license agreements. See the NOTICE file distributed
      13             :  *   with this work for additional information regarding copyright
      14             :  *   ownership. The ASF licenses this file to you under the Apache
      15             :  *   License, Version 2.0 (the "License"); you may not use this file
      16             :  *   except in compliance with the License. You may obtain a copy of
      17             :  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
      18             :  */
      19             : 
      20             : #include <resourcemodel/Fraction.hxx>
      21             : 
      22             : namespace writerfilter {
      23             : namespace resourcemodel {
      24             : 
      25             : // Stein's binary GCD for non-negative integers
      26             : // https://en.wikipedia.org/wiki/Binary_GCD_algorithm
      27           0 : static sal_uInt32 gcd(sal_uInt32 a, sal_uInt32 b)
      28             : {
      29           0 :     if (a == 0 || b == 0)
      30           0 :         return a | b;
      31             : 
      32           0 :     sal_uInt32 nShift = 0;
      33           0 :     while (((a | b) & 1) == 0)
      34             :     {
      35           0 :         a >>= 1;
      36           0 :         b >>= 1;
      37           0 :         ++nShift;
      38             :     }
      39             : 
      40           0 :     while ((a & 1) == 0)
      41           0 :         a >>= 1;
      42             : 
      43           0 :     do
      44             :     {
      45           0 :         while ((b & 1) == 0)
      46           0 :             b >>= 1;
      47             : 
      48           0 :         if (a < b)
      49             :         {
      50           0 :             b -= a;
      51             :         }
      52             :         else
      53             :         {
      54           0 :             sal_uInt32 nDiff = a - b;
      55           0 :             a = b;
      56           0 :             b = nDiff;
      57             :         }
      58             : 
      59           0 :         b >>= 1;
      60             :     }
      61             :     while (b != 0);
      62             : 
      63           0 :     return a << nShift;
      64             : }
      65             : 
      66           0 : static sal_uInt32 lcm(sal_Int32 a, sal_Int32 b)
      67             : {
      68           0 :     return abs(a * b) / gcd(abs(a), abs(b));
      69             : }
      70             : 
      71           0 : Fraction::Fraction(sal_Int32 nNumerator, sal_Int32 nDenominator)
      72             : {
      73           0 :     init(nNumerator, nDenominator);
      74           0 : }
      75             : 
      76           0 : Fraction::~Fraction()
      77             : {
      78           0 : }
      79             : 
      80           0 : void Fraction::init(sal_Int32 nNumerator, sal_Int32 nDenominator)
      81             : {
      82           0 :     sal_uInt32 nGCD = gcd(abs(nNumerator), abs(nDenominator));
      83             : 
      84           0 :     mnNumerator = nNumerator/ nGCD;
      85           0 :     mnDenominator = nDenominator / nGCD;
      86           0 : }
      87             : 
      88           0 : void Fraction::assign(const Fraction & rFraction)
      89             : {
      90           0 :     init(rFraction.mnNumerator, rFraction.mnDenominator);
      91           0 : }
      92             : 
      93           0 : Fraction Fraction::inverse() const
      94             : {
      95           0 :     return Fraction(mnDenominator, mnNumerator);
      96             : }
      97             : 
      98           0 : Fraction Fraction::operator + (const Fraction & rFraction) const
      99             : {
     100           0 :     sal_uInt32 nLCM = lcm(mnDenominator, rFraction.mnDenominator);
     101             : 
     102           0 :     return Fraction(mnNumerator * nLCM / mnDenominator + rFraction.mnNumerator * nLCM / rFraction.mnDenominator, nLCM);
     103             : }
     104             : 
     105           0 : Fraction Fraction::operator - (const Fraction & rFraction) const
     106             : {
     107           0 :     sal_uInt32 nLCM = lcm(mnDenominator, rFraction.mnDenominator);
     108             : 
     109           0 :     return Fraction(mnNumerator * nLCM / mnDenominator - rFraction.mnNumerator * nLCM / rFraction.mnDenominator, nLCM);
     110             : }
     111             : 
     112           0 : Fraction Fraction::operator * (const Fraction & rFraction) const
     113             : {
     114           0 :     return Fraction(mnNumerator * rFraction.mnNumerator, mnDenominator * rFraction.mnDenominator);
     115             : }
     116             : 
     117           0 : Fraction Fraction::operator / (const Fraction & rFraction) const
     118             : {
     119           0 :     return *this * rFraction.inverse();
     120             : }
     121             : 
     122           0 : Fraction Fraction::operator = (const Fraction & rFraction)
     123             : {
     124           0 :     assign(rFraction);
     125             : 
     126           0 :     return *this;
     127             : }
     128             : 
     129           0 : Fraction::operator sal_Int32() const
     130             : {
     131           0 :     return mnNumerator / mnDenominator;
     132             : }
     133             : 
     134           0 : Fraction::operator float() const
     135             : {
     136           0 :     return static_cast<float>(mnNumerator) / static_cast<float>(mnDenominator);
     137             : }
     138             : 
     139             : }}
     140             : 
     141             : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */