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sdrangel/sdrbase/dsp/hbfilterchainconverter.cpp

152 lines
4.2 KiB
C++

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2019 F4EXB //
// written by Edouard Griffiths //
// //
// This program is free software; you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation as version 3 of the License, or //
// (at your option) any later version. //
// //
// This program 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 General Public License V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////
#include <QString>
#include "hbfilterchainconverter.h"
double HBFilterChainConverter::convertToIndexes(unsigned int log2, unsigned int chainHash, std::vector<unsigned int>& chainIndexes)
{
chainIndexes.clear();
if (log2 == 0) {
return 0.0;
}
unsigned int s = 1;
unsigned int u = chainHash;
for (unsigned int i = 0; i < log2; i++) {
s *= 3;
}
u %= s; // scale
unsigned int ix = log2;
double shift = 0.0;
double shift_stage = 1.0 / (1<<(log2+1));
// base3 conversion
do
{
int r = u % 3;
chainIndexes.push_back(r);
shift += (r-1)*shift_stage;
shift_stage *= 2;
u /= 3;
ix--;
} while (u);
// continue shift with leading zeroes. ix has the number of leading zeroes.
for (unsigned int i = 0; i < ix; i++)
{
chainIndexes.push_back(0);
shift -= shift_stage;
shift_stage *= 2;
}
return shift;
}
double HBFilterChainConverter::convertToString(unsigned int log2, unsigned int chainHash, QString& chainString)
{
if (log2 == 0)
{
chainString = "C";
return 0.0;
}
unsigned int s = 1;
unsigned int u = chainHash;
chainString = "";
for (unsigned int i = 0; i < log2; i++) {
s *= 3;
}
u %= s; // scale
unsigned int ix = log2;
double shift = 0.0;
double shift_stage = 1.0 / (1<<(log2+1));
// base3 conversion
do
{
int r = u % 3;
if (r == 0) {
chainString = "L" + chainString;
} else if (r == 1) {
chainString = "C" + chainString;
} else if (r == 2) {
chainString = "H" + chainString;
}
shift += (r-1)*shift_stage;
shift_stage *= 2;
u /= 3;
ix--;
} while (u);
// continue shift with leading zeroes. ix has the number of leading zeroes.
for (unsigned int i = 0; i < ix; i++)
{
chainString = "L" + chainString;
shift -= shift_stage;
shift_stage *= 2;
}
return shift;
}
double HBFilterChainConverter::getShiftFactor(unsigned int log2, unsigned int chainHash)
{
if (log2 == 0)
{
return 0.0;
}
unsigned int s = 1;
unsigned int u = chainHash;
for (unsigned int i = 0; i < log2; i++) {
s *= 3;
}
u %= s; // scale
unsigned int ix = log2;
double shift = 0.0;
double shift_stage = 1.0 / (1<<(log2+1));
// base3 conversion
do
{
int r = u % 3;
shift += (r-1)*shift_stage;
shift_stage *= 2;
u /= 3;
ix--;
} while (u);
// continue shift with leading zeroes. ix has the number of leading zeroes.
for (unsigned int i = 0; i < ix; i++)
{
shift -= shift_stage;
shift_stage *= 2;
}
return shift;
}