92 lines
2.1 KiB
C++
92 lines
2.1 KiB
C++
/*
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* Copyright (C) 2016 by Jonathan Naylor G4KLX
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "RSSIInterpolator.h"
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#include "Log.h"
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#include <cstdio>
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#include <cstdlib>
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#include <cstring>
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#include <cctype>
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CRSSIInterpolator::CRSSIInterpolator() :
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m_map()
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{
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}
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CRSSIInterpolator::~CRSSIInterpolator()
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{
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m_map.clear();
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}
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bool CRSSIInterpolator::load(const std::string& filename)
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{
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FILE* fp = ::fopen(filename.c_str(), "rt");
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if (fp == NULL) {
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LogWarning("Cannot open the RSSI data file - %s", filename.c_str());
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return false;
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}
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char buffer[100U];
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while (::fgets(buffer, 100, fp) != NULL) {
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if (buffer[0U] == '#')
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continue;
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char* p1 = ::strtok(buffer, " \t\r\n");
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char* p2 = ::strtok(NULL, " \t\r\n");
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if (p1 != NULL && p2 != NULL) {
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uint16_t raw = uint16_t(::atoi(p1));
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int rssi = ::atoi(p2);
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m_map.insert(std::pair<uint16_t, int>(raw, rssi));
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}
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}
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::fclose(fp);
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LogInfo("Loaded %u RSSI data mapping points from %s", m_map.size(), filename.c_str());
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return true;
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}
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int CRSSIInterpolator::interpolate(uint16_t val) const
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{
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if (m_map.empty())
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return 0;
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std::map<uint16_t, int>::const_iterator it = m_map.lower_bound(val);
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if (it == m_map.end())
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return m_map.rbegin()->second;
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if (it == m_map.begin())
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return it->second;
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uint16_t x2 = it->first;
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int y2 = it->second;
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--it;
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uint16_t x1 = it->first;
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int y1 = it->second;
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float p = float(val - x1) / float(x2 - x1);
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return int((1.0F - p) * float(y1) + p * float(y2));
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}
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