/***************************************************************************
*
* write_hdr
*
*   Writes the specified values into a 1000-byte header block of the 
*   specified file, using the new standard CDC distributed data header format. 
*
* LAST UPDATE: 26 November 1997
*
* ARGUMENTS:
*
*   Name         Type       Description
*   ----         ----       -----------
*   outfile     *FILE       (Opened) input data file pointer
*   file_str     char[80]   Character string with outfile name 
*   instr        char[20]   Instrument (sensor) 
*   mis_val      short      Missing value (e.g., -9999) 
*   fields       short      Number of fields per pixel 
*   pixels       short      Number of pixels per scanline 
*   hi_fields    short      Number of high-resolution fields 
*   hi_pixels    short      Number of high-res pixels per scanline
*   scale       *short      Scaling factor (one per field) 
*   offset      *short      Offset (bias) factor (one per field) 
*   var_desc   **char       Field variable description (one per field) 
*
* ORIGINAL AUTHORS:
*   Don Anderson and Wesley Berg, CIRES/CDC, November 1997
*
* RETURNS:   0   If successful
*          < 0   If error
*
* NOTES:
*   (1) The passed file descriptor ("outfile") must be for a file which
*       has already been opened for writing.
*   (2) Binary write (fwrite) continues up to the 1000th byte of the file
*       (end of header)
*
***************************************************************************/

#include <stdio.h>

 int write_hdr ( FILE *outfile, char file_str[], char satellite[],
                 char sensor[], short mis_val, short satid, short fields,
                 short pixels, short hi_fields, short hi_pixels, float *scale,
                 float *offset, char **units, char **var_desc )

 {

 char   buff[5000] ;      /* Buffer for filler bytes  */
 int    error_flag ;      /* Error flag               */
 short  i ;               /* Generic counter          */

 error_flag = 0 ;

 fwrite ( file_str, 1, 80, outfile ) ;
 fwrite ( satellite, 1, 20, outfile ) ;
 fwrite ( sensor, 1, 20, outfile ) ;
 fwrite ( &satid, 2, 1, outfile ) ;
 fwrite ( &fields, 2, 1, outfile ) ;
 fwrite ( &pixels, 2, 1, outfile ) ;
 fwrite ( &hi_fields, 2, 1, outfile ) ;
 fwrite ( &hi_pixels, 2, 1, outfile ) ;
 fwrite ( &mis_val, 2, 1, outfile ) ;
 for ( i = 0 ; i < fields + hi_fields ; i++ ) 
   {
   fwrite ( &scale[i], 4, 1, outfile ) ;
   fwrite ( &offset[i], 4, 1, outfile ) ;
   fwrite ( units[i], 1, 40, outfile ) ;
   fwrite ( var_desc[i], 1, 80, outfile ) ;
   }

 if ( ! fwrite ( buff, 1, 5000 - 132 - ((fields+hi_fields)*128), outfile ) )
   error_flag = -1 ;

 return ( error_flag ) ;

 }