owlps/owlps-positioner/posutil.cc

/*
 * This file is part of the Owl Positioning System (OwlPS) project.
 * It is subject to the copyright notice and license terms in the
 * COPYRIGHT.t2t file found in the top-level directory of this
 * distribution and at
 *   https://code.lm7.fr/mcy/owlps/src/master/COPYRIGHT.t2t
 * No part of the OwlPS Project, including this file, may be copied,
 * modified, propagated, or distributed except according to the terms
 * contained in the COPYRIGHT.t2t file; the COPYRIGHT.t2t file must be
 * distributed along with this file, either separately or by replacing
 * this notice by the COPYRIGHT.t2t file's contents.
 */


#include "posutil.hh"
#include "posexcept.hh"
#include "stock.hh"
#include "configuration.hh"
#include "measurement.hh"

#include <owlps.h>

#include <cmath>

using namespace std ;



/* *** Maths *** */


double PosUtil::deg2rad(const double degrees)
{
  return degrees / (180.0 / M_PI) ;
}


double PosUtil::rad2deg(const double radians)
{
  return radians * (180.0 / M_PI) ;
}



/* *** Measurements *** */


/**
 * CPs that have not captured a Request must not have too much weight in
 * the computation. Thus, in the measurements lists we compare, we add
 * missing CPs with a very low SS value.
 *
 * Both lists can be completed, depending of the CPs they contain.
 * Both lists must initially contain at least one measurement.
 */
void PosUtil::complete_with_dummy_measurements(
  unordered_map<string, Measurement> &measurements1,
  unordered_map<string, Measurement> &measurements2)
{
  assert(! measurements1.empty()) ;
  assert(! measurements2.empty()) ;

  Measurement dummy ;
  dummy.add_ss(1, Configuration::int_value("positioning.smallest-ss")) ;

  for (auto i = measurements1.begin() ; i != measurements1.end() ; ++i)
    if (measurements2.find(i->first) == measurements2.end())
      {
        dummy.set_cp(&Stock::get_cp(i->first)) ;
        measurements2[i->first] = dummy ;
      }

  for (auto i = measurements2.begin() ; i != measurements2.end() ; ++i)
    if (measurements1.find(i->first) == measurements1.end())
      {
        dummy.set_cp(&Stock::get_cp(i->first)) ;
        measurements1[i->first] = dummy ;
      }
}


/**
 * Both lists must have the same size and contain the same keys:
 * you should call complete_with_dummy_measurements() before this
 * function.
 *
 * The similarity between the two lists is computed by averaging the
 * similarities between the elements of both lists, two by two, calling
 * Measurement::similarity().
 */
float PosUtil::similarity(
  unordered_map<string, Measurement> &measurements1,
  unordered_map<string, Measurement> &measurements2)
{
  assert(! measurements1.empty()) ;
  assert(measurements1.size() == measurements2.size()) ;

  float similarity = 0 ;

  for (auto i1 = measurements1.begin() ; i1 != measurements1.end() ; ++i1)
    {
      auto i2 = measurements2.find(i1->first) ;
      assert(i2 != measurements2.end()) ;
      similarity += i1->second.similarity(i2->second) ;
    }

  return similarity / measurements1.size() ;
}



/* *** Wi-Fi *** */


/**
 * @param channel A IEEE 802.11 channel or frequency in MHz or in Hz.
 * @returns The frequency in Hz.
 * @throw bad_channel if `channel` is not a valid channel or
 * frequency value.
 */
unsigned long PosUtil::wifi_channel_to_hz(const unsigned long &channel)
{
  switch (channel)
    {
    case 1:
    case OWL_80211_MHZ_CHANNEL_1:
    case OWL_80211_HZ_CHANNEL_1:
      return OWL_80211_HZ_CHANNEL_1 ;
    case 2:
    case OWL_80211_MHZ_CHANNEL_2:
    case OWL_80211_HZ_CHANNEL_2:
      return OWL_80211_HZ_CHANNEL_2 ;
    case 3:
    case OWL_80211_MHZ_CHANNEL_3:
    case OWL_80211_HZ_CHANNEL_3:
      return OWL_80211_HZ_CHANNEL_3 ;
    case 4:
    case OWL_80211_MHZ_CHANNEL_4:
    case OWL_80211_HZ_CHANNEL_4:
      return OWL_80211_HZ_CHANNEL_4 ;
    case 5:
    case OWL_80211_MHZ_CHANNEL_5:
    case OWL_80211_HZ_CHANNEL_5:
      return OWL_80211_HZ_CHANNEL_5 ;
    case 6:
    case OWL_80211_MHZ_CHANNEL_6:
    case OWL_80211_HZ_CHANNEL_6:
      return OWL_80211_HZ_CHANNEL_6 ;
    case 7:
    case OWL_80211_MHZ_CHANNEL_7:
    case OWL_80211_HZ_CHANNEL_7:
      return OWL_80211_HZ_CHANNEL_7 ;
    case 8:
    case OWL_80211_MHZ_CHANNEL_8:
    case OWL_80211_HZ_CHANNEL_8:
      return OWL_80211_HZ_CHANNEL_8 ;
    case 9:
    case OWL_80211_MHZ_CHANNEL_9:
    case OWL_80211_HZ_CHANNEL_9:
      return OWL_80211_HZ_CHANNEL_9 ;
    case 10:
    case OWL_80211_MHZ_CHANNEL_10:
    case OWL_80211_HZ_CHANNEL_10:
      return OWL_80211_HZ_CHANNEL_10 ;
    case 11:
    case OWL_80211_MHZ_CHANNEL_11:
    case OWL_80211_HZ_CHANNEL_11:
      return OWL_80211_HZ_CHANNEL_11 ;
    case 12:
    case OWL_80211_MHZ_CHANNEL_12:
    case OWL_80211_HZ_CHANNEL_12:
      return OWL_80211_HZ_CHANNEL_12 ;
    case 13:
    case OWL_80211_MHZ_CHANNEL_13:
    case OWL_80211_HZ_CHANNEL_13:
      return OWL_80211_HZ_CHANNEL_13 ;
    case 14:
    case OWL_80211_MHZ_CHANNEL_14:
    case OWL_80211_HZ_CHANNEL_14:
      return OWL_80211_HZ_CHANNEL_14 ;
    }

  // Error: wrong channel value
  throw bad_channel(channel) ;
}



/* *** Strings *** */


string PosUtil::int_to_mac(const uint32_t source)
{
  uint8_t bytes[6] ;
  memset(bytes, 0, 6) ;
  for (int i = 0 ; i < 4 ; ++i)
    bytes[i+2] = reinterpret_cast<const uint8_t*>(&source)[i] ;
  char mac_cstr[OWL_ETHER_ADDR_STRLEN] ;
  owl_mac_bytes_to_string_r(bytes, mac_cstr) ;
  string mac(mac_cstr) ;
  to_upper(mac) ;
  return mac ;
}