/disk01/web/ocssw/build/src/l0fix_modis/l0fix_modis.c

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/*----------------------------------------------------------------------
Copyright (C) 2000,  Space Science and Engineering Center, University
of Wisconsin-Madison, Madison WI.
      
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
------------------------------------------------------------------------*/


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <PGS_TD.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

#define buffsize_mb 0.5
#define primary_hdr_size 6


int main (int argc, char *argv[])
{
  int              n_packets = 0;
  int              read_cnt;
  long             strm_pos = 0;
  int              packet_length = 0;
  int              buf_pos = 0;
  int              buf_pos_last;
  int              bytes_left;
  int              last_pkt_in_file;
  int              last_pkt_in_buffer;
  int              found_start_time;
  int              buffsize;
  int              write;
  int              n_night=0;
  int              n_day=0;
  struct stat      filestat;
  
  static int pkt_len_off = 4;
  static int time_off = primary_hdr_size;
  static int time_cnt = 8;
  static int L0_true = 0;
  static int L0_false = 1;
  static int day_pkt_size = 642;
  static int night_pkt_size = 276;
  static unsigned char time_tag[8];

  char *cptr = (char *) &n_packets;

  double taitime_start;
  double taitime_stop;
  double taitime_tag;
  double taitime_good;
  double eps=1e-6;
  size_t status;

  char  utc_str[28];
  unsigned char *buffer, outbuf[384];
  FILE *stream, *stream_w=NULL;

  /*
    1) Get start and stop times

    ./fix_L0 L0file -1 -1

    2) fix L0

    ./fix_L0 L0file starttime stoptime outputL0
  */

  printf("fix_L0: Version as of 07/16/07\n\n");

  stream = fopen( argv[1], "r");
  if (stream == NULL) {
    printf("%s not found.\n", argv[1]);
    exit (-1);
  }
  fseek( stream, (long) 0, SEEK_SET);

  taitime_start = atof(argv[2]);
  taitime_stop  = atof(argv[3]);

  if (taitime_stop == -1) {
    taitime_stop=1e30;
  } else {
    stream_w = fopen( argv[4], "wb");
  }

  buffsize = buffsize_mb*1000000;
  buffer = (unsigned char *) malloc( buffsize*sizeof(unsigned char) );
  if ( buffer == NULL ) 
  {
    fseek( stream, (long) 0, SEEK_SET);
    return 1;
  }

  last_pkt_in_file = L0_false;
  found_start_time = L0_false;

  while ( last_pkt_in_file == L0_false )
  {
    last_pkt_in_buffer = L0_false;

    read_cnt = fread( buffer, sizeof(char), buffsize, stream );

    buf_pos = 0;
    while ( last_pkt_in_buffer == L0_false )
    {
      bytes_left = read_cnt - buf_pos;
      if ( bytes_left < day_pkt_size )
      {
        if ( bytes_left == 0 ) {
          last_pkt_in_buffer = L0_true;
          continue;
        }
        else if ((bytes_left == night_pkt_size) ||
                 (bytes_left == 2*night_pkt_size)) {
        }
        else if ( feof(stream) == 0 ) {
          last_pkt_in_buffer = L0_true;
          fseek( stream, strm_pos, SEEK_SET );
          continue;
        } else {
      free( buffer );

      printf("%d Total packets read\n", n_packets);
      printf("taitime_stop: %f\n", taitime_good);

      if (stream_w != NULL) fclose(stream_w);
      fclose(stream);

      if (atof(argv[2]) != -1) {
        stat(argv[4], &filestat);
        if (n_day*642+n_night*276 != filestat.st_size) {
          printf("output filesize discrepency.\n");
          printf("Computed filesize: %d\n", n_day*642+n_night*276);
          printf("Actual filesize:   %d\n", (int)filestat.st_size);
          return 3;
        }
      }

      return 0;
    }
      }

      packet_length = buffer[buf_pos + (pkt_len_off)]*256 +
                      buffer[buf_pos + pkt_len_off+1];
      packet_length += 1;
      packet_length += primary_hdr_size;

      write = 1;
      if (( packet_length != 642 ) && ( packet_length != 276 ))
      {
        if ( n_packets > 0 ) {
          printf("Packet with invalid length found %d %d\n", 
         n_packets, packet_length);
      write = 0;
        } 
      }


      memcpy( time_tag, &buffer[buf_pos + time_off], time_cnt );
      PGS_TD_EOSAMtoTAI( time_tag, &taitime_tag);

      //      if (n_packets == 300000) printf("%f\n", taitime_tag);

      if ( taitime_tag < taitime_start-eps || taitime_tag > taitime_stop+eps)
      {
    printf("Bad L0 packet: %d %d\n",
           taitime_tag < taitime_start,
           taitime_tag > taitime_stop);
    printf("Bad L0 packet: %f %f %f\n", 
           taitime_start, taitime_tag, taitime_stop);
    write = 0;
      }

      if (taitime_start == -1 && found_start_time == L0_false) {
      printf("taitime_start: %f\n", taitime_tag);
      found_start_time = L0_true;
      }

      if (write && stream_w != NULL) {
    status = fwrite(&buffer[buf_pos], packet_length, 1, stream_w);
    if (status != 1) {
      exit(4);
    }
      }

      if (write)
    taitime_good = taitime_tag;

      strm_pos += (long) packet_length;
      buf_pos_last = buf_pos;
      buf_pos += packet_length;
      n_packets++;

      if (write) {
    if (packet_length == 642) n_day++;
    if (packet_length == 276) n_night++;
      }

      if ((n_packets % 100000) == 0) {
    printf("%10d packets read\n", n_packets);
      }

    }

    if ( feof(stream) != 0 )
    {
      last_pkt_in_file = L0_true;
    }

    if ( ferror(stream) != 0 )
    {
      free( buffer );
      fseek( stream, (long) 0, SEEK_SET);
      return 2;
    }
  }
  free( buffer );

  printf("%d Total packets read\n", n_packets);
  printf("taitime_stop: %f\n", taitime_good);

  if (stream_w != NULL) fclose(stream_w);
  fclose(stream);

  if (atof(argv[2]) != -1) {
    stat(argv[4], &filestat);
    if (n_day*642+n_night*276 != filestat.st_size) {
      printf("output filesize discrepency.\n");
      printf("Computed filesize: %d\n", n_day*642+n_night*276);
      printf("Actual filesize:   %d\n", (int)filestat.st_size);
      return 3;
    }
  }

  return 0;
}