static char rcsid[]="$Id: testgmf.c,v 1.0 1992/07/28 23:07:53 maurer $";      
/***********************************************************************      
                                                                              
  testgmf.c                                                                   
                                                                              
  Function:  program illustrates how to read GMF G-matrix file                
                                                                              
  This file is part of the STARLab Magellan Altimeter Data Processing         
  Software.  Joe Twicken, June 1992.                                          
                                                                              
***********************************************************************/      
/* $Log: testgmf.c,v $                                                        
 * Revision 1.0  1992/07/28  23:07:53  maurer                                 
 * Initial revision                                                           
 * */                                                                         
                                                                              
#include <stdio.h>                                                            
                                                                              
#include "scvdr.h"                                                            
#include "scvparse.h"                                                         
                                                                              
#include "scvparse.i"                                                         
#include "scv_rdr.i"                                                          
                                                                              
#define RECNUM 10               /* Number data recs to read at once */        
                                                                              
int                                                                           
main(argc,argv)                                                               
int argc;                       /* Number of program arguments */             
char *argv[];                   /* Argument strings */                        
{                                                                             
        sfdu sf1;               /* CCSDS header SFDU label */                 
        sfdu sf2;               /* Keyword/value SFDU label */                
        sfdu sf3;               /* G-matrix header SFDU label */              
        sfdu sf4;               /* Aggr start marker SFDU label */            
                                                                              
        keyval_t *kv2;          /* Catalog keyword/value list */              
        keyval_t *kv4;          /* Aggr smarker keyword/value list */         
                                                                              
        gh_rec gh;              /* G-matrix header record */                  
        gr_rec gr[RECNUM];      /* G-matrix data records */                   
                                                                              
        int ng;                 /* Number of data records remaining */        
        int nread;              /* Number of data records to read */          
        int Gnum;               /* G-matrix ID number */                      
                                                                              
        float gbr;              /* Angle-range G-matrix value */              
                                                                              
        char product_file_name[80];/* Product file name */                    
                                                                              
        FILE *f_gmf;            /* GMF file pointer */                        
                                                                              
        /* Check usage */                                                     
                                                                              
        if (argc != 2) {                                                      
                fprintf(stderr,"usage: testgmf gmf_file\n");                  
                exit(1);                                                      
        }                                                                     
                                                                              
        /* Open the GMF file for reading */                                   
                                                                              
        if ((f_gmf = fopen(argv[1],"r")) == NULL) {                           
                fprintf(stderr,                                               
                        "testgmf: [main] can't open %s\n",argv[1]);           
                exit(2);                                                      
        }                                                                     
                                                                              
        /* Read the 4 header SFDU's. Remember to free the keyword/value       
           list pointers with free_catalog() when they are no longer          
           needed */                                                          
                                                                              
        if (hdr_read(f_gmf,&sf1,&sf2,&kv2,&sf3,&gh,&sf4,&kv4)) {              
                fprintf(stderr,                                               
                        "testgmf: [main] can't read gmf header\n");           
                exit(3);                                                      
        }                                                                     
                                                                              
        /* Do something with the header values. The example here shows        
           how to get the number of G-matrices and product file name */       
                                                                              
        ng = (int) gh.gh_ng;                                                  
        strncpy(product_file_name,kv2[0].val,sizeof(product_file_name));      
                                                                              
        /* Allocate space for the variable length fields in the               
           G-matrix data records. gmf_allocn() need only be                   
           called once per file; sufficient memory space is allocated         
           to accommodate the largest possible data record */                 
                                                                              
        if (gmf_allocn(gr,RECNUM,&gh)) {                                      
                fprintf(stderr,                                               
                "testgmf: [main] can't allocate memory space\n");             
                exit(4);                                                      
        }                                                                     
                                                                              
        /* Read G-matrix data records, 10 at a time */                        
                                                                              
        while (ng > 0) {                                                      
                                                                              
                /* Read the data records 10 at a time. Note that              
                   gmf_readn() returns the number of records                  
                   successfully read */                                       
                                                                              
                nread = (ng > RECNUM) ? RECNUM : ng;                          
                if (gmf_readn(f_gmf,gr,nread) != nread) {                     
                        fprintf(stderr,                                       
                        "testgmf: [main] can't read gmf data recs\n");        
                        exit(5);                                              
                }                                                             
                ng -= nread;                                                  
                                                                              
                /* Do something with the data values. The example             
                   here shows how to read the G-matrix ID number and          
                   the first angle-range G-matrix value for the first         
                   data record */                                             
                                                                              
                Gnum = (int) gr[0].gr_Gnum;                                   
                gbr  = gr[0].gr_gbr[0];                                       
        }                                                                     
                                                                              
        /* Free the memory allocated for the variable length fields           
           in the G-matrix data records. The gmf_freen() routine must         
           be called once for each call to gmf_allocn() */                    
                                                                              
        gmf_freen(gr,RECNUM);                                                 
                                                                              
        /* Free the header keyword/value lists */                             
                                                                              
        free_catalog(kv2);                                                    
        free_catalog(kv4);                                                    
                                                                              
        /* Close the GMF file */                                              
                                                                              
        fclose(f_gmf);                                                        
                                                                              
        return(0);                                                            
}