/*
@(#) File name: fsdf_vtoc.c  Release: 1.1  Date: 7/28/94, 14:00:09
*/
/****************************************************************************
FUNCTION:

	VTOC_read

AUTHOR: Meng-chun Lin, Mail stop 157B, EOSDIS LANGLEY DAAC, Hampton, VA 23666
	(804)864-8657.  e-mail: M.LIN@LaRC.NASA.GOV

PURPOSE/DESCRIPTION:

	Function VTOC_read() reads a record of FIRE Standard Data Format (SDF) 
	Volume Table Of Contents (VTOC).  This can either be a record in the 
	VTOC file or the first physical record of the ancillary and/or 
	observation data files.  The VTOC records are in ASCII format.  There 
	are 10 fields defined in a SDF VTOC record with a total of 160 bytes.  
	Each field is separated with at least a blank.  See NOTES section for 
	the detailed fields definitions.
	
	Bytes 81 through 160 is defined for geometry description.  In SRB 
	data, however, they are subdivided into the following fields: 
	81 - 88		keyword ( AUXFIL=) to identify ancillary file name
	89 - 96		ancillary file name
	97 - 160	blanks
	
INVOCATION:
	returned_value = VTOC_read (fptr, rec_size, &toc);

  WHERE 
	<fptr> - I
	   is the file pointer for the Volume Table of Contents (VTOC) file,
	   ancillary file, or observation data files.
	<rec_size> - I
	   is the size of each VTOC record (some data sets come in 80 bytes 
	   long, some 160 bytes long).
	<toc> - I, o
	   returns a record that stores all individual field values from 
	   reading a VTOC record.
	<returned_value> - O
	   returns the length of a VTOC record string when there is no error,
	   or returns 0 when it's a blank line (or extra "CR" character).  
	   It returns -1 if it's a bad file pointer or end of file is reached.

FILE/RECORD REFERENCES:	None.

EXTERNAL ROUTINES: None.

NOTES:
1.	The field definitions for VTOC file are described as follows: 

	field pos. 	field descriptions 
	(starts with 1)
	-------------	--------------------------------------------------
	1 - 4		file sequence number
	6 - 11		record number within a file 
	13 - 20		record name
	22 - 35		earliest observation date and gmt in file
	37 - 50		latest observation date and gmt in file 
	52 - 57		northern most latitude covered by data in the file 
	59 - 64		southern most latitude covered by data in the file
	66 - 72		western most longitude covered by data in the file
	74 - 80		eastern most longitude covered by data in the file

Fields 81 through 160 are used for geometry description.  In SRB data, 
however, they are subdivided into the following fields: 
	81 - 88		keyword ( AUXFIL=) to identify ancillary file name
	89 - 96		ancillary file name
	97 - 160	blank fields

2.	Because the VTOC records of some data sets come with two "Carriage 
	Return" characters at the end of the record.  The next call to this  
	function will result in a blank line (i.e., a return value of 0).

*****************************************************************************/
#ifdef sccs
static char sccsid[] = "File: fsdf_vtoc.c  Release: 1.1  Date: 7/28/94, 14:00:09"
#endif

	/* System include files. */
#include <stdio.h>
#include <sys/types.h>
#include <string.h> 

	/* Local C library include file. */
#include "fire_sdf.h"

int  VTOC_read (fptr, rec_size, toc)
FILE  *fptr;
int  rec_size;
vtoc_data  *toc;		/* Data type defined in local include file. */
{

    int  len;
    char  buf[240], *s;


    if (fptr == NULL)    return (-1); 

	/*** FIRE SDF VTOC records are in ASCII format. */
    if (fgets (buf, rec_size+1, fptr) != NULL)    {
	len = str_trim (buf, 0);
	/*** The following if statement is needed because the VTOC of some  
	 *** data sets come with two "Carriage Return" characters at the end 
	 *** of the record.  The extra CR character will cause the next read 
	 *** to be a blank line. 
	 ***/
	if (strlen (buf) == 0)   return (0);
	
	sscanf (buf, "%d %d %s", &(toc->fnum), &(toc->rnum), toc->fname);
	sscanf (&(buf[BEG_GMT-1]), "%14s", toc->i_date_gmt);
	sscanf (&(buf[END_GMT-1]), "%14s", toc->o_date_gmt);
	sscanf (&(buf[BEG_LATLON-1]), "%f %f %f %f", &(toc->nlat_max),
	          &(toc->slat_max), &(toc->wlon_max), &(toc->elon_max));
	if (strlen(buf) > (AUX_FLDS - 1))
	    sscanf (&(buf[AUX_FLDS - 1]), "%s", toc->aux_file);
	


/****************************************************************************
 *  The "aux_file" field is specific for different data.  For example, SRB 
 *  data use this field to define the map grids (ancillary files).  Other 
 *  specific definition should be define as a conditional compilation and 
 *  codes are added from here.
 ****************************************************************************/
	/*****  SRB data specific, tape no. p0101 through p0115   *****/
#ifdef  SRB
        if (strstr (toc->aux_file, KEYWORD_AUX) != (char *)NULL)    {
            s = &toc->aux_file[0]+sizeof(KEYWORD_AUX)-1;
            strcpy (toc->aux_file, s);
        } else    {
            fprintf (stderr, "ERROR: ' AUXFIL=' keyword not found.  ");
            fprintf (stderr, "The file may be bad.\n");
            strcpy (toc->aux_file, "\0");
        }

#endif	/* SRB */
        return (strlen (buf));
    } else
        return (-1);
}