esp32-ogn-tracker/utils/aprs2igc.cc

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#include <vector>
#include <algorithm>

#include "format.h"

static int APRS2IGC(char *Out, const char *Inp, int GeoidSepar)      // convert APRS positon message into IGC B-record
{ int Len=0;
  const char *Msg = strchr(Inp, ':'); if(Msg==0) return 0;           // colon: separates header and message
  Msg++;                                                             // where message starts
  if(Msg[0]!='/' || Msg[7]!='h') return 0;
  const char *Pos = Msg+8; if(Pos[4]!='.' || Pos[14]!='.') return 0; // where position starts
  const char *ExtPos = strstr(Pos+18, " !W"); if(ExtPos[5]=='!') ExtPos+=3; else ExtPos=0;
  Out[Len++]='B';                                                    // B-record
  memcpy(Out+Len, Msg+1, 6); Len+=6;                                 // copy UTC time
  memcpy(Out+Len, Pos, 4); Len+=4;                                   // copy DDMM
  memcpy(Out+Len, Pos+5, 2); Len+=2;                                 // copy fractional MM
  Out[Len++] = ExtPos?ExtPos[0]:'0';                                 // extended precision
  Out[Len++] = Pos[7];                                               // copy N/S sign
  memcpy(Out+Len, Pos+9, 5); Len+=5;                                 // copy DDMM
  memcpy(Out+Len, Pos+15,2); Len+=2;                                 // copy fractional MM
  Out[Len++] = ExtPos?ExtPos[1]:'0';                                 // extended precision
  Out[Len++] = Pos[17];                                              // copy E/W sign
  Out[Len++] = 'A';
  memcpy(Out+Len, "          ", 10);
  const char *FL = strstr(Pos+18, " FL");
  if(FL)                                                             // pressure altitude
  { float PressAlt=atof(FL+3); PressAlt*=30.4; int32_t Alt=floor(PressAlt+0.5);
    if(Alt<0) { Alt = (-Alt); Out[Len] = '-'; Format_UnsDec(Out+Len+1, (uint32_t)Alt, 4); }
         else { Format_UnsDec(Out+Len, (uint32_t)Alt, 5); }
  }
  Len+=5;
  if(Pos[27]=='A' && Pos[28]=='=')                                   // geometrical altitude
  { int32_t Alt=atol(Pos+29); Alt=(Alt*3+5)/10; Alt+=GeoidSepar;     // convert to meters and add GeoidSepar for HAE
    if(Alt<0) { Alt = (-Alt); Out[Len] = '-'; Format_UnsDec(Out+Len+1, (uint32_t)Alt, 4); }
         else { Format_UnsDec(Out+Len, (uint32_t)Alt, 5); }
  }
  Len+=5;
  Out[Len]=0; return Len; }

  static bool Earlier(const char *Line1, const char *Line2) { return strcmp(Line1, Line2)<0; }

static int Verbose    =  1;
static int GeoidSepar = 40;

static FILE *OutFile = 0;

int main(int argc, char *argv[])
{ if(argc<2)
  { printf("Usage: %s <own-aircraft-APRS-call> <input-file.aprs>\n", argv[0]);
    return 0; }

  const char *OwnAcft = argv[1]; int OwnAcftLen = strlen(OwnAcft);
  char OutFileName[32]; strcpy(OutFileName, OwnAcft); strcat(OutFileName, ".IGC");

  const char *InpFileName = argv[2];
  FILE *InpFile;
  if(InpFileName==0 || strcmp(InpFileName,"-")==0) InpFile=stdin;
  else
  { InpFile=fopen(InpFileName, "rt");
    if(InpFile==0) { printf("Cannot open %s for read\n", InpFileName); return 0; }
  }

  std::vector<char *> OutLine;
  char InpLine[256];
  // char OutLine[256];
  int InpLines=0;
  // int OutLines=0;
  char *Out=0;
  for( ; ; )
  { if(fgets(InpLine, 256, InpFile)==0) break;
    char *EOL = strchr(InpLine, '\n'); if(EOL==0) break;
    *EOL = 0;
    InpLines++;
    if(memcmp(InpLine, OwnAcft, OwnAcftLen)) continue;
    if(Out==0) Out = (char *)malloc(60);
    int OutLen=APRS2IGC(Out, InpLine, GeoidSepar);
    if(OutLen>0)
    { if(Verbose) printf("%s => %s [%d]\n", InpLine, Out, OutLen);
      OutLine.push_back(Out); Out=0; }
  }
  if(Out) { free(Out); Out=0; }
  if(InpFile!=stdin) fclose(InpFile);
  printf("%d lines from %s\n", InpLines, InpFileName);

  std::sort(OutLine.begin(), OutLine.end(), Earlier);
  OutFile=fopen(OutFileName, "wt");
  if(OutFile==0) { printf("Cannot open %s for write\n", OutFileName); return 0; }
  for(int Idx=0; Idx<OutLine.size(); Idx++)
  { fprintf(OutFile, "%s\n", OutLine[Idx]); }
  fclose(OutFile);
  printf("%d lines to %s\n", OutLine.size(), OutFileName);

  return 0; }