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/*
* Copyright (C) 2013-2015, 2019 by the Konclude Developer Team.
*
* This file is part of the reasoning system Konclude.
* For details and support, see <http://konclude.com/>.
*
* Konclude is free software: you can redistribute it and/or modify
* it under the terms of version 3 of the GNU Lesser General Public
* License (LGPLv3) as published by the Free Software Foundation.
*
* Konclude is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU (Lesser) General Public License for more details.
*
* You should have received a copy of the GNU (Lesser) General Public
* License along with Konclude. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include "CMath.h"
namespace Konclude {
namespace Utilities {
CMath::CMath() {
}
CMath::~CMath() {
}
qint64 CMath::log2(qint64 x) {
if(x<Q_INT64_C(0x100000000)){
// code from website http://www.ssw.uni-linz.ac.at/Teaching/Lectures/Sem/2002/reports/Priewasser/index.html
if(x<0x10000){
if(x<0x100){
if(x<0x10){
if(x<0x4){
if(x<0x2)
return 0;
else
return 1;
} else {
if(x<0x8)
return 2;
else
return 3;
}
} else {
if(x<0x40){
if(x<0x20)
return 4;
else
return 5;
} else {
if(x<0x80)
return 6;
else
return 7;
}
}
} else {
if(x<0x1000){
if(x<0x400){
if(x<0x200)
return 8;
else
return 9;
} else {
if(x<0x800)
return 10;
else
return 11;
}
} else {
if(x<0x4000){
if(x<0x2000)
return 12;
else
return 13;
} else {
if(x<0x8000)
return 14;
else
return 15;
}
}
}
} else {
if(x<0x1000000){
if(x<0x100000){
if(x<0x40000){
if(x<0x20000)
return 16;
else
return 17;
} else {
if(x<0x80000)
return 18;
else
return 19;
}
} else {
if(x<0x400000){
if(x<0x200000)
return 20;
else
return 21;
} else {
if(x<0x800000)
return 22;
else
return 23;
}
}
} else {
if(x<0x10000000){
if(x<0x4000000){
if(x<0x2000000)
return 24;
else
return 25;
} else {
if(x<0x8000000)
return 26;
else
return 27;
}
} else {
if(x<0x40000000){
if(x<0x20000000)
return 28;
else
return 29;
} else {
if(x<0x80000000)
return 30;
else
return 31;
}
}
}
}
} else {
return log2(x>>32)+32;
}
}
}; // end namespace Utilities
}; // end namespace Konclude
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