/*
  Converter for RTCM3 data to RINEX.
  $Id: rtcm3torinex.c,v 1.15 2007/01/11 14:10:13 stoecker Exp $
  Copyright (C) 2005-2006 by Dirk Stoecker <stoecker@euronik.eu>

  This software is a complete NTRIP-RTCM3 to RINEX converter as well as
  a module of the BNC tool for multiformat conversion. Contact Dirk
  Stöcker for suggestions and bug reports related to the RTCM3 to RINEX
  conversion problems and the author of BNC for all the other problems.

  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; either version 2 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 for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  or read http://www.gnu.org/licenses/gpl.txt
*/

#include <ctype.h>
#include <errno.h>
#include <math.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>

#ifndef NO_RTCM3_MAIN
#include <getopt.h>
#include <netdb.h>
#include <netinet/in.h>
#include <sys/socket.h>
#endif

#ifndef sparc
#include <stdint.h>
#endif

#include "rtcm3torinex.h"

/* CVS revision and version */
static char revisionstr[] = "$Revision: 1.15 $";

static uint32_t CRC24(long size, const unsigned char *buf)
{
  uint32_t crc = 0;
  int i;

  while(size--)
  {
    crc ^= (*buf++) << (16);
    for(i = 0; i < 8; i++)
    {
      crc <<= 1;
      if(crc & 0x1000000)
        crc ^= 0x01864cfb;
    }
  }
  return crc;
}

static int GetMessage(struct RTCM3ParserData *handle)
{
  unsigned char *m, *e;
  int i;

  m = handle->Message+handle->SkipBytes;
  e = handle->Message+handle->MessageSize;
  handle->NeedBytes = handle->SkipBytes = 0;
  while(e-m >= 3)
  {
    if(m[0] == 0xD3)
    {
      handle->size = ((m[1]&3)<<8)|m[2];
      if(e-m >= handle->size+6)
      {
        if((uint32_t)((m[3+handle->size]<<16)|(m[3+handle->size+1]<<8)
        |(m[3+handle->size+2])) == CRC24(handle->size+3, m))
        {
          handle->SkipBytes = handle->size;
          break;
        }
        else
          ++m;
      }
      else
      {
        handle->NeedBytes = handle->size+6;
        break;
      }
    }
    else
      ++m;
  }
  if(e-m < 3)
    handle->NeedBytes = 3;
  
  /* copy buffer to front */
  i = m - handle->Message;
  if(i && m < e)
    memmove(handle->Message, m, (size_t)(handle->MessageSize-i));
  handle->MessageSize -= i;

  return !handle->NeedBytes;
}

#define LOADBITS(a) \
{ \
  while((a) > numbits) \
  { \
    if(!size--) break; \
    bitfield = (bitfield<<8)|*(data++); \
    numbits += 8; \
  } \
}

/* extract bits from data stream
   b = variable to store result, a = number of bits */
#define GETBITS(b, a) \
{ \
  LOADBITS(a) \
  b = (bitfield<<(64-numbits))>>(64-(a)); \
  numbits -= (a); \
}

/* extract bits from data stream
   b = variable to store result, a = number of bits */
#define GETBITSSIGN(b, a) \
{ \
  LOADBITS(a) \
  b = ((int64_t)(bitfield<<(64-numbits)))>>(64-(a)); \
  numbits -= (a); \
}

#define SKIPBITS(b) { LOADBITS(b) numbits -= (b); }

struct leapseconds { /* specify the day of leap second */
  int day;        /* this is the day, where 23:59:59 exists 2 times */
  int month;      /* not the next day! */
  int year;
  int taicount;
}; 
static const int months[13] = {0,31,28,31,30,31,30,31,31,30,31,30,31};
static const struct leapseconds leap[] = {
/*{31, 12, 1971, 11},*/
/*{31, 12, 1972, 12},*/
/*{31, 12, 1973, 13},*/
/*{31, 12, 1974, 14},*/
/*{31, 12, 1975, 15},*/
/*{31, 12, 1976, 16},*/
/*{31, 12, 1977, 17},*/
/*{31, 12, 1978, 18},*/
/*{31, 12, 1979, 19},*/
{30, 06, 1981,20},
{30, 06, 1982,21},
{30, 06, 1983,22},
{30, 06, 1985,23},
{31, 12, 1987,24},
{31, 12, 1989,25},
{31, 12, 1990,26},
{30, 06, 1992,27},
{30, 06, 1993,28},
{30, 06, 1994,29},
{31, 12, 1995,30},
{30, 06, 1997,31},
{31, 12, 1998,32},
{31, 12, 2005,33},
{0,0,0,0} /* end marker */
};
#define LEAPSECONDS     14 /* only needed for approx. time */
#define GPSLEAPSTART    19 /* 19 leap seconds existed at 6.1.1980 */

static int longyear(int year, int month)
{
  if(!(year % 4) && (!(year % 400) || (year % 100)))
  {
    if(!month || month == 2)
      return 1;
  }
  return 0;
}

static int gnumleap(int year, int month, int day)
{
  int ls = 0;
  const struct leapseconds *l;

  for(l = leap; l->taicount && year >= l->year; ++l)
  {
    if(year > l->year || month > l->month || day > l->day)
       ls = l->taicount - GPSLEAPSTART;
  }
  return ls;
}

static void updatetime(int *week, int *tow, int tk)
{
  int y,m,d,k,l;
  unsigned int j = *week*(7*24*60*60) + *tow + 5*24*60*60+3*60*60;
  int glo_daynumber = 0, glo_timeofday;
  for(y = 1980; j >= (unsigned int)(k = (l = (365+longyear(y,0)))*24*60*60)
  + gnumleap(y+1,1,1); ++y)
  {
    j -= k; glo_daynumber += l;
  }
  for(m = 1; j >= (unsigned int)(k = (l = months[m]+longyear(y, m))*24*60*60)
  + gnumleap(y, m+1, 1); ++m)
  {
    j -= k; glo_daynumber += l;
  }
  for(d = 1; j >= 24UL*60UL*60UL + gnumleap(y, m, d+1); ++d)
    j -= 24*60*60;
  glo_daynumber -= 16*365+4-d;
  glo_timeofday = j-gnumleap(y, m, d);

  if(tk < 5*60*1000 && glo_timeofday > 23*60*60)
    *tow += 24*60*60;
  else if(glo_timeofday < 5*60 && tk > 23*60*60*1000)
    *tow -= 24*60*60;
  *tow += tk/1000-glo_timeofday;
  if(*tow < 0) {*tow += 24*60*60*7; --*week; }
  if(*tow >= 24*60*60*7) {*tow -= 24*60*60*7; ++*week; }
}

int RTCM3Parser(struct RTCM3ParserData *handle)
{
  int ret=0;

  while(!ret && GetMessage(handle))
  {
    /* using 64 bit integer types, as it is much easier than handling
    the long datatypes in 32 bit */
    uint64_t numbits = 0, bitfield = 0;
    int size = handle->size, type;
    int syncf, old = 0;
    unsigned char *data = handle->Message+3;

    GETBITS(type,12)
    switch(type)
    {
    case 1001: case 1002: case 1003: case 1004:
      if(handle->GPSWeek)
      {
        int lastlockl1[64];
        int lastlockl2[64];
        struct gnssdata *gnss;
        int i, num, wasamb=0;

        for(i = 0; i < 64; ++i)
          lastlockl1[i] = lastlockl2[i] = 0;

        gnss = &handle->DataNew;

        SKIPBITS(12) /* id */
        GETBITS(i,30)
        if(i/1000 < (int)handle->GPSTOW - 86400)
          ++handle->GPSWeek;
        handle->GPSTOW = i/1000;
        if(gnss->week && (gnss->timeofweek != i || gnss->week
        != handle->GPSWeek))
        {
          handle->Data = *gnss;
          memset(gnss, 0, sizeof(*gnss));
          old = 1;
        }
        gnss->timeofweek = i;
        gnss->week = handle->GPSWeek;

        GETBITS(syncf,1) /* sync */
        GETBITS(i,5)
        gnss->numsats = i;
        SKIPBITS(4) /* smind, smint */

        for(num = 0; num < gnss->numsats; ++num)
        {
          int sv, code, l1range, c,l,s,ce,le,se,amb=0;

          GETBITS(sv, 6);
          gnss->satellites[num] = (sv < 40 ? sv : sv+80);
          /* L1 */
          GETBITS(code, 1);
          if(code)
          {
            c = GNSSDF_P1DATA;  ce = GNSSENTRY_P1DATA;
            l = GNSSDF_L1PDATA; le = GNSSENTRY_L1PDATA;
            s = GNSSDF_S1PDATA; se = GNSSENTRY_S1PDATA;
          }
          else
          {
            c = GNSSDF_C1DATA;  ce = GNSSENTRY_C1DATA;
            l = GNSSDF_L1CDATA; le = GNSSENTRY_L1CDATA;
            s = GNSSDF_S1CDATA; se = GNSSENTRY_S1CDATA;
          }
          GETBITS(l1range, 24);
          if((l1range&((1<<24)-1)) != 0x80000)
          {
            gnss->dataflags[num] |= c;
            gnss->measdata[num][ce] = l1range*0.02;
          }
          GETBITSSIGN(i, 20);
          if((i&((1<<20)-1)) != 0x80000)
          {
            gnss->dataflags[num] |= l;
            gnss->measdata[num][le] = l1range*0.02+i*0.0005;
          }
          GETBITS(i, 7);
          lastlockl1[sv] = i;
          if(handle->lastlockl1[sv] > i)
            gnss->dataflags[num] |= GNSSDF_LOCKLOSSL1;
          if(type == 1002 || type == 1004)
          {
            GETBITS(amb,8);
            if(amb && (gnss->dataflags[num] & c))
            {
              gnss->measdata[num][ce] += amb*299792.458;
              gnss->measdata[num][le] += amb*299792.458;
              ++wasamb;
            }
            GETBITS(i, 8);
            if(i)
            {
              gnss->dataflags[num] |= s;
              gnss->measdata[num][se] = i*0.25;
              i /= 4*4;
              if(i > 9) i = 9;
              else if(i < 1) i = 1;
              gnss->snrL1[num] = i;
            }
          }
          gnss->measdata[num][le] /= GPS_WAVELENGTH_L1;
          if(type == 1003 || type == 1004)
          {
            /* L2 */
            GETBITS(code,2);
            if(code)
            {
              c = GNSSDF_P2DATA;  ce = GNSSENTRY_P2DATA;
              l = GNSSDF_L2PDATA; le = GNSSENTRY_L2PDATA;
              s = GNSSDF_S2PDATA; se = GNSSENTRY_S2PDATA;
            }
            else
            {
              c = GNSSDF_C2DATA;  ce = GNSSENTRY_C2DATA;
              l = GNSSDF_L2CDATA; le = GNSSENTRY_L2CDATA;
              s = GNSSDF_S2CDATA; se = GNSSENTRY_S2CDATA;
            }
            GETBITSSIGN(i,14);
            if((i&((1<<14)-1)) != 0x2000)
            {
              gnss->dataflags[num] |= c;
              gnss->measdata[num][ce] = l1range*0.02+i*0.02
              +amb*299792.458;
            }
            GETBITSSIGN(i,20);
            if((i&((1<<20)-1)) != 0x80000)
            {
              gnss->dataflags[num] |= l;
              gnss->measdata[num][le] = l1range*0.02+i*0.0005
              +amb*299792.458;
            }
            GETBITS(i,7);
            lastlockl2[sv] = i;
            if(handle->lastlockl2[sv] > i)
              gnss->dataflags[num] |= GNSSDF_LOCKLOSSL2;
            if(type == 1004)
            {
              GETBITS(i, 8);
              if(i)
              {
                gnss->dataflags[num] |= s;
                gnss->measdata[num][se] = i*0.25;
                i /= 4*4;
                if(i > 9) i = 9;
                else if(i < 1) i = 1;
                gnss->snrL2[num] = i;
              }
            }
            gnss->measdata[num][le] /= GPS_WAVELENGTH_L2;
          }
        }
        for(i = 0; i < 64; ++i)
        {
          handle->lastlockl1[i] = lastlockl1[i];
          handle->lastlockl2[i] = lastlockl2[i];
        }
        if(!syncf && !old)
        {
          handle->Data = *gnss;
          memset(gnss, 0, sizeof(*gnss));
        }
        if(!syncf || old)
        {
          if(wasamb) /* not RINEX compatible without */
            ret = 1;
          else
            ret = 2;
        }
      }
      break;
    case 1009: case 1010: case 1011: case 1012:
      {
        int lastlockl1[64];
        int lastlockl2[64];
        struct gnssdata *gnss;
        int i, num;
        int wasamb=0;

        for(i = 0; i < 64; ++i)
          lastlockl1[i] = lastlockl2[i] = 0;

        gnss = &handle->DataNew;

        SKIPBITS(12) /* id */;
        GETBITS(i,27) /* tk */

        updatetime(&handle->GPSWeek, &handle->GPSTOW, i);
        i = handle->GPSTOW*1000;
        if(gnss->week && (gnss->timeofweek != i || gnss->week
        != handle->GPSWeek))
        {
          handle->Data = *gnss;
          memset(gnss, 0, sizeof(*gnss));
          old = 1;
        }

        gnss->timeofweek = i;
        gnss->week = handle->GPSWeek;

        GETBITS(syncf,1) /* sync */
        GETBITS(i,5)
        gnss->numsats += i;

        SKIPBITS(4) /* smind, smint */

        for(num = gnss->numsats-i; num < gnss->numsats; ++num)
        {
          int sv, code, l1range, c,l,s,ce,le,se,amb=0;
          int freq;

          GETBITS(sv, 6)
          gnss->satellites[num] = sv-1 + PRN_GLONASS_START;
          /* L1 */
          GETBITS(code, 1)
          GETBITS(freq, 5)
          if(code)
          {
            c = GNSSDF_P1DATA;  ce = GNSSENTRY_P1DATA;
            l = GNSSDF_L1PDATA; le = GNSSENTRY_L1PDATA;
            s = GNSSDF_S1PDATA; se = GNSSENTRY_S1PDATA;
          }
          else
          {
            c = GNSSDF_C1DATA;  ce = GNSSENTRY_C1DATA;
            l = GNSSDF_L1CDATA; le = GNSSENTRY_L1CDATA;
            s = GNSSDF_S1CDATA; se = GNSSENTRY_S1CDATA;
          }
          GETBITS(l1range, 25)
          if((l1range&((1<<25)-1)) != 0x80000)
          {
            gnss->dataflags[num] |= c;
            gnss->measdata[num][ce] = l1range*0.02;
          }
          GETBITSSIGN(i, 20)
          if((i&((1<<20)-1)) != 0x80000)
          {
            gnss->dataflags[num] |= l;
            gnss->measdata[num][le] = l1range*0.02+i*0.0005;
          }
          GETBITS(i, 7)
          lastlockl1[sv] = i;
          if(handle->lastlockl1[sv] > i)
            gnss->dataflags[num] |= GNSSDF_LOCKLOSSL1;
          if(type == 1010 || type == 1012)
          {
            GETBITS(amb,7)
            if(amb && (gnss->dataflags[num] & c))
            {
              gnss->measdata[num][ce] += amb*599584.916;
              gnss->measdata[num][le] += amb*599584.916;
              ++wasamb;
            }
            GETBITS(i, 8)
            if(i)
            {
              gnss->dataflags[num] |= s;
              gnss->measdata[num][se] = i*0.25;
              i /= 4*4;
              if(i > 9) i = 9;
              else if(i < 1) i = 1;
              gnss->snrL1[num] = i;
            }
          }
          gnss->measdata[num][le] /= GLO_WAVELENGTH_L1(freq-7);
          if(type == 1011 || type == 1012)
          {
            /* L2 */
            GETBITS(code,2)
            if(code)
            {
              c = GNSSDF_P2DATA;  ce = GNSSENTRY_P2DATA;
              l = GNSSDF_L2PDATA; le = GNSSENTRY_L2PDATA;
              s = GNSSDF_S2PDATA; se = GNSSENTRY_S2PDATA;
            }
            else
            {
              c = GNSSDF_C2DATA;  ce = GNSSENTRY_C2DATA;
              l = GNSSDF_L2CDATA; le = GNSSENTRY_L2CDATA;
              s = GNSSDF_S2CDATA; se = GNSSENTRY_S2CDATA;
            }
            GETBITSSIGN(i,14)
            if((i&((1<<14)-1)) != 0x2000)
            {
              gnss->dataflags[num] |= c;
              gnss->measdata[num][ce] = l1range*0.02+i*0.02
              +amb*599584.916;
            }
            GETBITSSIGN(i,20)
            if((i&((1<<20)-1)) != 0x80000)
            {
              gnss->dataflags[num] |= l;
              gnss->measdata[num][le] = l1range*0.02+i*0.0005
              +amb*599584.915;
            }
            GETBITS(i,7)
            lastlockl2[sv] = i;
            if(handle->lastlockl2[sv] > i)
              gnss->dataflags[num] |= GNSSDF_LOCKLOSSL2;
            if(type == 1012)
            {
              GETBITS(i, 8)
              if(i)
              {
                gnss->dataflags[num] |= s;
                gnss->measdata[num][se] = i*0.25;
                i /= 4*4;
                if(i > 9) i = 9;
                else if(i < 1) i = 1;
                gnss->snrL2[num] = i;
              }
            }
            gnss->measdata[num][le] /= GLO_WAVELENGTH_L2(freq-7);
          }
          if(!sv || sv > 24)
          {
            --num; --gnss->numsats;
          }
        }
        for(i = 0; i < 64; ++i)
        {
          handle->lastlockl1[i] = lastlockl1[i];
          handle->lastlockl2[i] = lastlockl2[i];
        }
        if(!syncf && !old)
        {
          handle->Data = *gnss;
          memset(gnss, 0, sizeof(*gnss));
        }
        if(!syncf || old)
        {
          if(wasamb) /* not RINEX compatible without */
            ret = 1;
          else
            ret = 2;
        }
      }
      break;
    }
  }
  return ret;
}

struct Header
{
  const char *version;
  const char *pgm;
  const char *marker;
  const char *observer;
  const char *receiver;
  const char *antenna;
  const char *position;
  const char *antennaposition;
  const char *wavelength;
  const char *typesofobs; /* should not be modified outside */
  const char *timeoffirstobs; /* should not be modified outside */
};

#define MAXHEADERLINES 50
#define MAXHEADERBUFFERSIZE 4096
struct HeaderData
{
  union
  {
    struct Header named;
    const char *unnamed[MAXHEADERLINES];
  } data;
  int  numheaders;
};

struct converttimeinfo {
  int second;    /* seconds of GPS time [0..59] */
  int minute;    /* minutes of GPS time [0..59] */
  int hour;      /* hour of GPS time [0..24] */
  int day;       /* day of GPS time [1..28..30(31)*/
  int month;     /* month of GPS time [1..12]*/
  int year;      /* year of GPS time [1980..] */
};

static void converttime(struct converttimeinfo *c, int week, int tow)
{
  int i, k, doy, j; /* temporary variables */
  j = week*(7*24*60*60) + tow + 5*24*60*60;
  for(i = 1980; j >= (k = (365+longyear(i,0))*24*60*60); ++i)
    j -= k;
  c->year = i;
  doy = 1+ (j / (24*60*60));
  j %= (24*60*60);
  c->hour = j / (60*60);
  j %= (60*60);
  c->minute = j / 60;
  c->second = j % 60;
  j = 0;
  for(i = 1; j + (k = months[i] + longyear(c->year,i)) < doy; ++i)
    j += k;
  c->month = i;
  c->day = doy - j;
}

#ifndef NO_RTCM3_MAIN
void RTCM3Error(const char *fmt, ...)
{
  va_list v;
  va_start(v, fmt);
  vfprintf(stderr, fmt, v);
  va_end(v);
}
#endif

void RTCM3Text(const char *fmt, ...)
{
  va_list v;
  va_start(v, fmt);
  vprintf(fmt, v);
  va_end(v);
}

#define NUMSTARTSKIP 3
void HandleHeader(struct RTCM3ParserData *Parser)
{
  struct HeaderData hdata;
  char thebuffer[MAXHEADERBUFFERSIZE];
  char *buffer = thebuffer;
  size_t buffersize = sizeof(thebuffer);
  int i;

  hdata.data.named.version =
  "     2.11           OBSERVATION DATA    M (Mixed)"
  "           RINEX VERSION / TYPE";

  {
    const char *str;
    time_t t;
    struct tm * t2;

#ifdef NO_RTCM3_MAIN
    if(revisionstr[0] == '$')
    {
      char *a;
      int i=0;
      for(a = revisionstr+11; *a && *a != ' '; ++a)
        revisionstr[i++] = *a;
      revisionstr[i] = 0;
    }
#endif

    str = getenv("USER");
    if(!str) str = "";
    t = time(&t);
    t2 = gmtime(&t);
    hdata.data.named.pgm = buffer;
    i = 1+snprintf(buffer, buffersize,
    "RTCM3TORINEX %-7.7s%-20.20s%04d-%02d-%02d %02d:%02d    "
    "PGM / RUN BY / DATE",
    revisionstr, str, 1900+t2->tm_year, t2->tm_mon+1, t2->tm_mday, t2->tm_hour,
    t2->tm_min);
    buffer += i; buffersize -= i;

    hdata.data.named.observer = buffer;
    i = 1+snprintf(buffer, buffersize,
    "%-20.20s                                        "
    "OBSERVER / AGENCY", str);
    buffer += i; buffersize -= i;
  }

  hdata.data.named.marker =
  "RTCM3TORINEX                                                "
  "MARKER NAME";

  hdata.data.named.receiver =
  "                                                            "
  "REC # / TYPE / VERS";

  hdata.data.named.antenna =
  "                                                            "
  "ANT # / TYPE";

  hdata.data.named.position =
  "         .0000         .0000         .0000                  "
  "APPROX POSITION XYZ";

  hdata.data.named.antennaposition =
  "         .0000         .0000         .0000                  "
  "ANTENNA: DELTA H/E/N";
  
  hdata.data.named.wavelength =
  "     1     1                                                "
  "WAVELENGTH FACT L1/2";

  {
#define CHECKFLAGS(a, b) \
    if(flags & GNSSDF_##a##DATA) \
    { \
      if(data[RINEXENTRY_##b##DATA]) \
      { \
        Parser->dataflag2[data[RINEXENTRY_##b##DATA]-1] = GNSSDF_##a##DATA; \
        Parser->datapos2[data[RINEXENTRY_##b##DATA]-1] = GNSSENTRY_##a##DATA; \
      } \
      else \
      { \
        Parser->dataflag[Parser->numdatatypes] = GNSSDF_##a##DATA; \
        Parser->datapos[Parser->numdatatypes] = GNSSENTRY_##a##DATA; \
        data[RINEXENTRY_##b##DATA] = ++Parser->numdatatypes; \
        snprintf(tbuffer+tbufferpos, sizeof(tbuffer)-tbufferpos, "    "#b); \
        tbufferpos += 6; \
      } \
    }

    int flags = Parser->startflags;
    int data[RINEXENTRY_NUMBER];
    char tbuffer[6*RINEXENTRY_NUMBER+1];
    int tbufferpos = 0;
    for(i = 0; i < RINEXENTRY_NUMBER; ++i)
      data[i] = 0;
    for(i = 0; i < Parser->Data.numsats; ++i)
      flags |= Parser->Data.dataflags[i];

    CHECKFLAGS(C1,C1)
    CHECKFLAGS(C2,C2)
    CHECKFLAGS(P1,P1)
    CHECKFLAGS(P2,P2)
    CHECKFLAGS(L1C,L1)
    CHECKFLAGS(L1P,L1)
    CHECKFLAGS(L2C,L2)
    CHECKFLAGS(L2P,L2)
    CHECKFLAGS(D1C,D1)
    CHECKFLAGS(D1P,D1)
    CHECKFLAGS(D2C,D2)
    CHECKFLAGS(D2P,D2)
    CHECKFLAGS(S1C,S1)
    CHECKFLAGS(S1P,S1)
    CHECKFLAGS(S2C,S2)
    CHECKFLAGS(S2P,S2)

    hdata.data.named.typesofobs = buffer;
    i = 1+snprintf(buffer, buffersize,
    "%6i%-54.54s# / TYPES OF OBSERV", Parser->numdatatypes, tbuffer);
    if(Parser->numdatatypes>9)
    {
      i += snprintf(buffer+i-1, buffersize,
      "\n      %-54.54s# / TYPES OF OBSERV", tbuffer+9*6);
    }
    buffer += i; buffersize -= i;
  }

  {
    struct converttimeinfo cti;
    converttime(&cti, Parser->Data.week,
    (int)floor(Parser->Data.timeofweek/1000.0));
    hdata.data.named.timeoffirstobs = buffer;
      i = 1+snprintf(buffer, buffersize,
    "  %4d    %2d    %2d    %2d    %2d   %10.7f     GPS         "
    "TIME OF FIRST OBS", cti.year%100, cti.month, cti.day, cti.hour,
    cti.minute, cti.second + fmod(Parser->Data.timeofweek/1000.0,1.0));

    buffer += i; buffersize -= i;
  }

  hdata.numheaders = 11;

  if(Parser->headerfile)
  {
    FILE *fh;
    if((fh = fopen(Parser->headerfile, "r")))
    {
      size_t siz;
      char *lastblockstart;
      if((siz = fread(buffer, 1, buffersize-1, fh)) > 0)
      {
        buffer[siz] = '\n';
        if(siz == buffersize)
        {
          RTCM3Error("Header file is too large. Only %d bytes read.",
          (int)siz);
        }
        /* scan the file line by line and enter the entries in the list */
        /* warn for "# / TYPES OF OBSERV" and "TIME OF FIRST OBS" */
        /* overwrites entries, except for comments */
        lastblockstart = buffer;
        for(i = 0; i < (int)siz; ++i)
        {
          if(buffer[i] == '\n')
          { /* we found a line */
            char *end;
            while(buffer[i+1] == '\r')
              ++i; /* skip \r in case there are any */
            end = buffer+i;
            while(*end == '\t' || *end == ' ' || *end == '\r' || *end == '\n')
              *(end--) = 0;
            if(end-lastblockstart < 60+5) /* short line */
              RTCM3Error("Short Header line '%s' ignored.\n", lastblockstart);
            else
            {
              int pos;
              if(!strcmp("COMMENT", lastblockstart+60))
                pos = hdata.numheaders;
              else
              {
                for(pos = 0; pos < hdata.numheaders; ++pos)
                {
                  if(!strcmp(hdata.data.unnamed[pos]+60, lastblockstart+60))
                    break;
                }
                if(!strcmp("# / TYPES OF OBSERV", lastblockstart+60)
                || !strcmp("TIME OF FIRST OBS", lastblockstart+60))
                {
                  RTCM3Error("Overwriting header '%s' is dangerous.\n",
                  lastblockstart+60);
                }
              }
              if(pos >= MAXHEADERLINES)
              {
                RTCM3Error("Maximum number of header lines of %d reached.\n",
                MAXHEADERLINES);
              }
              else if(!strcmp("END OF HEADER", lastblockstart+60))
              {
                RTCM3Error("End of header ignored.\n");
              }
              else
              {
                hdata.data.unnamed[pos] = lastblockstart;
                if(pos == hdata.numheaders)
                  ++hdata.numheaders;
              }
            }
            lastblockstart = buffer+i+1;
          }
        }
      }
      else
      {
        RTCM3Error("Could not read data from headerfile '%s'.\n",
        Parser->headerfile);
      }
      fclose(fh);
    }
    else
    {
      RTCM3Error("Could not open header datafile '%s'.\n",
      Parser->headerfile);
    }
  }

#ifndef NO_RTCM3_MAIN
  for(i = 0; i < hdata.numheaders; ++i)
    RTCM3Text("%s\n", hdata.data.unnamed[i]);
  RTCM3Text("                                                            "
  "END OF HEADER\n");
#endif
}

void HandleByte(struct RTCM3ParserData *Parser, unsigned int byte)
{
  Parser->Message[Parser->MessageSize++] = byte;
  if(Parser->MessageSize >= Parser->NeedBytes)
  {
    int r;
    while((r = RTCM3Parser(Parser)))
    {
      int i, j, o;
      struct converttimeinfo cti;

      if(Parser->init < NUMSTARTSKIP) /* skip first epochs to detect correct data types */
      {
        ++Parser->init;

        if(Parser->init == NUMSTARTSKIP)
          HandleHeader(Parser);
        else
        {
          for(i = 0; i < Parser->Data.numsats; ++i)
            Parser->startflags |= Parser->Data.dataflags[i];
          continue;
        }
      }
      if(r == 2 && !Parser->validwarning)
      {
        RTCM3Text("No valid RINEX! All values are modulo 299792.458!"
        "           COMMENT\n");
        Parser->validwarning = 1;
      }

      converttime(&cti, Parser->Data.week,
      (int)floor(Parser->Data.timeofweek/1000.0));
      RTCM3Text(" %02d %2d %2d %2d %2d %10.7f  0%3d",
      cti.year%100, cti.month, cti.day, cti.hour, cti.minute, cti.second
      + fmod(Parser->Data.timeofweek/1000.0,1.0), Parser->Data.numsats);
      for(i = 0; i < 12 && i < Parser->Data.numsats; ++i)
      {
        if(Parser->Data.satellites[i] <= PRN_GPS_END)
          RTCM3Text("G%02d", Parser->Data.satellites[i]);
        else if(Parser->Data.satellites[i] >= PRN_GLONASS_START
        && Parser->Data.satellites[i] <= PRN_GLONASS_END)
          RTCM3Text("R%02d", Parser->Data.satellites[i] - (PRN_GLONASS_START-1));
        else
          RTCM3Text("%3d", Parser->Data.satellites[i]);
      }
      RTCM3Text("\n");
      o = 12;
      j = Parser->Data.numsats - 12;
      while(j > 0)
      {
        RTCM3Text("                                ");
        for(i = o; i < o+12 && i < Parser->Data.numsats; ++i)
        {
          if(Parser->Data.satellites[i] <= PRN_GPS_END)
            RTCM3Text("G%02d", Parser->Data.satellites[i]);
          else if(Parser->Data.satellites[i] >= PRN_GLONASS_START
          && Parser->Data.satellites[i] <= PRN_GLONASS_END)
            RTCM3Text("R%02d", Parser->Data.satellites[i] - (PRN_GLONASS_START-1));
          else if(Parser->Data.satellites[i] >= PRN_WAAS_START
          && Parser->Data.satellites[i] <= PRN_WAAS_END)
            RTCM3Text("S%02d", Parser->Data.satellites[i] - PRN_WAAS_START);
          else
            RTCM3Text("%3d", Parser->Data.satellites[i]);
        }
        RTCM3Text("\n");
        j -= 12;
        o += 12;
      }
      for(i = 0; i < Parser->Data.numsats; ++i)
      {
        for(j = 0; j < Parser->numdatatypes; ++j)
        {
          int v = 0;
          int df = Parser->dataflag[j];
          int pos = Parser->datapos[j];
          if((Parser->Data.dataflags[i] & df)
          && !isnan(Parser->Data.measdata[i][pos])
          && !isinf(Parser->Data.measdata[i][pos]))
          {
            v = 1;
          }
          else
          {
            df = Parser->dataflag2[j];
            pos = Parser->datapos2[j];

            if((Parser->Data.dataflags[i] & df)
            && !isnan(Parser->Data.measdata[i][pos])
            && !isinf(Parser->Data.measdata[i][pos]))
            {
              v = 1;
            }
          }

          if(!v)
          { /* no or illegal data */
            RTCM3Text("                ");
          }
          else
          {
            char lli = ' ';
            char snr = ' ';
            if(df & (GNSSDF_L1CDATA|GNSSDF_L1PDATA))
            {
              if(Parser->Data.dataflags[i] & GNSSDF_LOCKLOSSL1)
                lli = '1';
              snr = '0'+Parser->Data.snrL1[i];
            }
            if(df & (GNSSDF_L2CDATA|GNSSDF_L2PDATA))
            {
              if(Parser->Data.dataflags[i] & GNSSDF_LOCKLOSSL2)
                lli = '1';
              snr = '0'+Parser->Data.snrL2[i];
            }
            RTCM3Text("%14.3f%c%c",
            Parser->Data.measdata[i][pos],lli,snr);
          }
          if(j%5 == 4 || j == Parser->numdatatypes-1)
            RTCM3Text("\n");
        }
      }
    }
  }
}

#ifndef NO_RTCM3_MAIN
static char datestr[]     = "$Date: 2007/01/11 14:10:13 $";

/* The string, which is send as agent in HTTP request */
#define AGENTSTRING "NTRIP NtripRTCM3ToRINEX"

#define MAXDATASIZE 1000 /* max number of bytes we can get at once */

static const char encodingTable [64] = {
  'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P',
  'Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f',
  'g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v',
  'w','x','y','z','0','1','2','3','4','5','6','7','8','9','+','/'
};

/* does not buffer overrun, but breaks directly after an error */
/* returns the number of required bytes */
static int encode(char *buf, int size, const char *user, const char *pwd)
{
  unsigned char inbuf[3];
  char *out = buf;
  int i, sep = 0, fill = 0, bytes = 0;

  while(*user || *pwd)
  {
    i = 0;
    while(i < 3 && *user) inbuf[i++] = *(user++);
    if(i < 3 && !sep)    {inbuf[i++] = ':'; ++sep; }
    while(i < 3 && *pwd)  inbuf[i++] = *(pwd++);
    while(i < 3)         {inbuf[i++] = 0; ++fill; }
    if(out-buf < size-1)
      *(out++) = encodingTable[(inbuf [0] & 0xFC) >> 2];
    if(out-buf < size-1)
      *(out++) = encodingTable[((inbuf [0] & 0x03) << 4)
               | ((inbuf [1] & 0xF0) >> 4)];
    if(out-buf < size-1)
    {
      if(fill == 2)
        *(out++) = '=';
      else
        *(out++) = encodingTable[((inbuf [1] & 0x0F) << 2)
                 | ((inbuf [2] & 0xC0) >> 6)];
    }
    if(out-buf < size-1)
    {
      if(fill >= 1)
        *(out++) = '=';
      else
        *(out++) = encodingTable[inbuf [2] & 0x3F];
    }
    bytes += 4;
  }
  if(out-buf < size)
    *out = 0;
  return bytes;
}

static int stop = 0;

struct Args
{
  const char *server;
  int         port;
  const char *user;
  const char *password;
  const char *data;
  const char *headerfile;
};

/* option parsing */
#ifdef NO_LONG_OPTS
#define LONG_OPT(a)
#else
#define LONG_OPT(a) a
static struct option opts[] = {
{ "data",       required_argument, 0, 'd'},
{ "server",     required_argument, 0, 's'},
{ "password",   required_argument, 0, 'p'},
{ "port",       required_argument, 0, 'r'},
{ "header",     required_argument, 0, 'f'},
{ "user",       required_argument, 0, 'u'},
{ "help",       no_argument,       0, 'h'},
{0,0,0,0}};
#endif
#define ARGOPT "-d:hp:r:s:u:f:"

static const char *geturl(const char *url, struct Args *args)
{
  static char buf[1000];
  static char *Buffer = buf;
  static char *Bufend = buf+sizeof(buf);

  if(strncmp("ntrip:", url, 6))
    return "URL must start with 'ntrip:'.";
  url += 6; /* skip ntrip: */

  if(*url != '@' && *url != '/')
  {
    /* scan for mountpoint */
    args->data = Buffer;
    while(*url && *url != '@' && *url != '/' && Buffer != Bufend)
      *(Buffer++) = *(url++);
    if(Buffer == args->data)
      return "Mountpoint required.";
    else if(Buffer >= Bufend-1)
      return "Parsing buffer too short.";
    *(Buffer++) = 0;
  }

  if(*url == '/') /* username and password */
  {
    ++url;
    args->user = Buffer;
    while(*url && *url != '@' && *url != ':' && Buffer != Bufend)
      *(Buffer++) = *(url++);
    if(Buffer == args->user)
      return "Username cannot be empty.";
    else if(Buffer >= Bufend-1)
      return "Parsing buffer too short.";
    *(Buffer++) = 0;

    if(*url == ':') ++url;

    args->password = Buffer;
    while(*url && *url != '@' && Buffer != Bufend)
      *(Buffer++) = *(url++);
    if(Buffer == args->password)
      return "Password cannot be empty.";
    else if(Buffer >= Bufend-1)
      return "Parsing buffer too short.";
    *(Buffer++) = 0;
  }

  if(*url == '@') /* server */
  {
    ++url;
    args->server = Buffer;
    while(*url && *url != ':' && Buffer != Bufend)
      *(Buffer++) = *(url++);
    if(Buffer == args->server)
      return "Servername cannot be empty.";
    else if(Buffer >= Bufend-1)
      return "Parsing buffer too short.";
    *(Buffer++) = 0;

    if(*url == ':')
    {
      char *s2 = 0;
      args->port = strtol(++url, &s2, 10);
      if(*s2 || args->port <= 0 || args->port > 0xFFFF)
        return "Illegal port number.";
      url = s2;
    }
  }

  return *url ? "Garbage at end of server string." : 0;
}

static int getargs(int argc, char **argv, struct Args *args)
{
  int res = 1;
  int getoptr;
  int help = 0;
  char *t;

  args->server = "www.euref-ip.net";
  args->port = 2101;
  args->user = "";
  args->password = "";
  args->data = 0;
  args->headerfile = 0;
  help = 0;

  do
  {
#ifdef NO_LONG_OPTS
    switch((getoptr = getopt(argc, argv, ARGOPT)))
#else
    switch((getoptr = getopt_long(argc, argv, ARGOPT, opts, 0)))
#endif
    {
    case 's': args->server = optarg; break;
    case 'u': args->user = optarg; break;
    case 'p': args->password = optarg; break;
    case 'd': args->data = optarg; break;
    case 'f': args->headerfile = optarg; break;
    case 'h': help=1; break;
    case 'r': 
      args->port = strtoul(optarg, &t, 10);
      if((t && *t) || args->port < 1 || args->port > 65535)
        res = 0;
      break;
    case 1:
      {
        const char *err;
        if((err = geturl(optarg, args)))
        {
          RTCM3Error("%s\n\n", err);
          res = 0;
        }
      }
      break;
    case -1: break;
    }
  } while(getoptr != -1 || !res);

  datestr[0] = datestr[7];
  datestr[1] = datestr[8];
  datestr[2] = datestr[9];
  datestr[3] = datestr[10];
  datestr[5] = datestr[12];
  datestr[6] = datestr[13];
  datestr[8] = datestr[15];
  datestr[9] = datestr[16];
  datestr[4] = datestr[7] = '-';
  datestr[10] = 0;

  if(!res || help)
  {
    RTCM3Error("Version %s (%s) GPL\nUsage: %s -s server -u user ...\n"
    " -d " LONG_OPT("--data       ") "the requested data set\n"
    " -f " LONG_OPT("--headerfile ") "file for RINEX header information\n"
    " -s " LONG_OPT("--server     ") "the server name or address\n"
    " -p " LONG_OPT("--password   ") "the login password\n"
    " -r " LONG_OPT("--port       ") "the server port number (default 2101)\n"
    " -u " LONG_OPT("--user       ") "the user name\n"
    "or using an URL:\n%s ntrip:mountpoint[/username[:password]][@server[:port]]\n"
    , revisionstr, datestr, argv[0], argv[0]);
    exit(1);
  }
  return res;
}

/* let the output complete a block if necessary */
static void signalhandler(int sig)
{
  if(!stop)
  {
    RTCM3Error("Stop signal number %d received. "
    "Trying to terminate gentle.\n", sig);
    stop = 1;
    alarm(1);
  }
}

/* for some reason we had to abort hard (maybe waiting for data */
#ifdef __GNUC__
static __attribute__ ((noreturn)) void signalhandler_alarm(
int sig __attribute__((__unused__)))
#else /* __GNUC__ */
static void signalhandler_alarm(int sig)
#endif /* __GNUC__ */
{
  RTCM3Error("Programm forcefully terminated.\n");
  exit(1);
}

int main(int argc, char **argv)
{
  struct Args args;
  struct RTCM3ParserData Parser;

  setbuf(stdout, 0);
  setbuf(stdin, 0);
  setbuf(stderr, 0);

  {
    char *a;
    int i=0;
    for(a = revisionstr+11; *a && *a != ' '; ++a)
      revisionstr[i++] = *a;
    revisionstr[i] = 0;
  }

  signal(SIGINT, signalhandler);
  signal(SIGALRM,signalhandler_alarm);
  signal(SIGQUIT,signalhandler);
  signal(SIGTERM,signalhandler);
  signal(SIGPIPE,signalhandler);
  memset(&Parser, 0, sizeof(Parser));
  {
    time_t tim;
    tim = time(0) - ((10*365+2+5)*24*60*60+LEAPSECONDS);
    Parser.GPSWeek = tim/(7*24*60*60);
    Parser.GPSTOW = tim%(7*24*60*60);
  }

  if(getargs(argc, argv, &args))
  {
    int i, sockfd, numbytes;  
    char buf[MAXDATASIZE];
    struct hostent *he;
    struct sockaddr_in their_addr; /* connector's address information */

    Parser.headerfile = args.headerfile;

    if(!(he=gethostbyname(args.server)))
    {
      RTCM3Error("Function gethostbyname: %s\n", strerror(errno));
      exit(1);
    }
    if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
    {
      RTCM3Error("Function socket: %s\n", strerror(errno));
      exit(1);
    }
    their_addr.sin_family = AF_INET;    /* host byte order */
    their_addr.sin_port = htons(args.port);  /* short, network byte order */
    their_addr.sin_addr = *((struct in_addr *)he->h_addr);
    memset(&(their_addr.sin_zero), '\0', 8);
    if(connect(sockfd, (struct sockaddr *)&their_addr,
    sizeof(struct sockaddr)) == -1)
    {
      RTCM3Error("Function connect: %s\n", strerror(errno));
      exit(1);
    }

    if(!args.data)
    {
      i = snprintf(buf, MAXDATASIZE,
      "GET / HTTP/1.0\r\n"
      "User-Agent: %s/%s\r\n"
#ifdef UNUSED
      "Accept: */*\r\n"
      "Connection: close\r\n"
#endif
      "\r\n"
      , AGENTSTRING, revisionstr);
    }
    else
    {
      i=snprintf(buf, MAXDATASIZE-40, /* leave some space for login */
      "GET /%s HTTP/1.0\r\n"
      "User-Agent: %s/%s\r\n"
#ifdef UNUSED
      "Accept: */*\r\n"
      "Connection: close\r\n"
#endif
      "Authorization: Basic "
      , args.data, AGENTSTRING, revisionstr);
      if(i > MAXDATASIZE-40 && i < 0) /* second check for old glibc */
      {
        RTCM3Error("Requested data too long\n");
        exit(1);
      }
      i += encode(buf+i, MAXDATASIZE-i-4, args.user, args.password);
      if(i > MAXDATASIZE-4)
      {
        RTCM3Error("Username and/or password too long\n");
        exit(1);
      }
      buf[i++] = '\r';
      buf[i++] = '\n';
      buf[i++] = '\r';
      buf[i++] = '\n';
    }
    if(send(sockfd, buf, (size_t)i, 0) != i)
    {
      RTCM3Error("Function send: %s\n", strerror(errno));
      exit(1);
    }
    if(args.data)
    {
      int k = 0;
      while(!stop && (numbytes=recv(sockfd, buf, MAXDATASIZE-1, 0)) != -1)
      {
        if(!k)
        {
          if(numbytes < 12 || strncmp("ICY 200 OK\r\n", buf, 12))
          {
            RTCM3Error("Could not get the requested data: ");
            for(k = 0; k < numbytes && buf[k] != '\n' && buf[k] != '\r'; ++k)
            {
              RTCM3Error("%c", isprint(buf[k]) ? buf[k] : '.');
            }
            RTCM3Error("\n");
            exit(1);
          }
          ++k;
        }
        else
        {
          int z;
          for(z = 0; z < numbytes && !stop; ++z)
            HandleByte(&Parser, (unsigned int) buf[z]);
        }
      }
    }
    else
    {
      while((numbytes=recv(sockfd, buf, MAXDATASIZE-1, 0)) > 0)
      {
        fwrite(buf, (size_t)numbytes, 1, stdout);
      }
    }

    close(sockfd);
  }
  return 0;
}
#endif /* NO_RTCM3_MAIN */