eccodes/examples/C/bufr_attributes.c

/*
 * Copyright 2005-2015 ECMWF.
 *
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
 *
 * In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
 * virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
 */

/*
 * C Implementation: bufr_attributes
 *
 * Description: how to read attributes of keys in BUFR messages.
 *
 */

#include "eccodes.h"


int main(int argc,char* argv[])
{
    FILE* in = NULL;
    
    /* message handle. Required in all the eccodes calls acting on a message.*/
    codes_handle* h=NULL;
    
    char* units= NULL;
    char* unitsPercent= NULL;
    long longVal;
    double doubleVal;
    size_t values_len=0, desc_len=0, len=0;
    int i, err=0;
    int cnt=0;
    char* infile = "../../data/bufr/syno_multi.bufr";

    in=fopen(infile,"r");
    if (!in) {
        printf("ERROR: unable to open file %s\n", infile);
        return 1;
    }
    
    /* loop over the messages in the bufr file */
    while ((h = codes_handle_new_from_file(NULL,in,PRODUCT_BUFR,&err)) != NULL || err != CODES_SUCCESS)
    {
        if (h == NULL) {
            printf("Error: unable to create handle for message %d\n",cnt);
            cnt++;
            continue;
        }
    
        printf("message: %d\n",cnt);
    
        /* we need to instruct ecCodes to expand the descriptors 
          i.e. unpack the data values */
        CODES_CHECK(codes_set_long(h,"unpack",1),0);
    
        /* ----------------------------------------------------------------
           We will read the value and all the attributes available for
           the 2m temperature.
        -------------------------------------------------------------------*/ 
        
        /* get the value as double */
        CODES_CHECK(codes_get_double(h,"airTemperatureAt2M",&doubleVal),0);
        printf("  airTemperatureAt2M: %.2f\n",doubleVal);
    
        /* get the element's code (see BUFR code table B) */
        CODES_CHECK(codes_get_long(h,"airTemperatureAt2M->code",&longVal),0);
        printf("  airTemperatureAt2M->code: %ld\n",longVal);
        
        /* get the element's units (see BUFR code table B) */
        
        /* get the size and allocate memory*/
        CODES_CHECK(codes_get_length(h, "airTemperatureAt2M->units", &len), 0);
        units = (char*)malloc(len*sizeof(char));
        
        /* get the values*/
        codes_get_string(h, "airTemperatureAt2M->units", units, &len);
        printf("  airTemperatureAt2M->units: %s\n", units);
    
        /* get the element's scale (see BUFR code table B) */
        CODES_CHECK(codes_get_long(h,"airTemperatureAt2M->scale",&longVal),0);
        printf("  airTemperatureAt2M->scale: %ld\n",longVal);
        
        /* get the element's reference (see BUFR code table B) */
        CODES_CHECK(codes_get_long(h,"airTemperatureAt2M->reference",&longVal),0);
        printf("  airTemperatureAt2M->reference: %ld\n",longVal);
        
         /* get the element's width (see BUFR code table B) */
        CODES_CHECK(codes_get_long(h,"airTemperatureAt2M->width",&longVal),0);
        printf("  airTemperatureAt2M->width: %ld\n",longVal);
    
        /* --------------------------------------------------------------------
           The 2m temperature data element in this message has an associated 
           field: percentConfidence. Its value and attributes can be accessed 
           in a similar manner as was shown above for 2m temperature. 
        -------------------------------------------------------------------*/ 
        
         /* get the value as long */
        CODES_CHECK(codes_get_long(h,"airTemperatureAt2M->percentConfidence",&longVal),0);
        printf("  airTemperatureAt2M->percentConfidence: %ld\n",longVal);
        
        /* get the element's code (see BUFR code table B) */
        CODES_CHECK(codes_get_long(h,"airTemperatureAt2M->percentConfidence->code",&longVal),0);
        printf("  airTemperatureAt2M->percentConfidence->code: %ld\n",longVal);
        
        /* get the element's units (see BUFR code table B) */
        
        /* get the size and allocate memory*/
        CODES_CHECK(codes_get_length(h, "airTemperatureAt2M->percentConfidence->units", &len), 0);
        unitsPercent = (char*)malloc(len*sizeof(char));
        
        /* get the values*/
        codes_get_string(h, "airTemperatureAt2M->percentConfidence->units", unitsPercent, &len);
        printf("  airTemperatureAt2M->percentConfidence->units: %s\n", unitsPercent);
    
        /* get the element's scale (see BUFR code table B) */
        CODES_CHECK(codes_get_long(h,"airTemperatureAt2M->percentConfidence->scale",&longVal),0);
        printf("  airTemperatureAt2M->percentConfidence->scale: %ld\n",longVal);
        
        /* get the element's reference (see BUFR code table B) */
        CODES_CHECK(codes_get_long(h,"airTemperatureAt2M->percentConfidence->reference",&longVal),0);
        printf("  airTemperatureAt2M->percentConfidence->reference: %ld\n",longVal);
        
         /* get the element's width (see BUFR code table B) */
        CODES_CHECK(codes_get_long(h,"airTemperatureAt2M->percentConfidence->width",&longVal),0);
        printf("  airTemperatureAt2M->percentConfidence->width: %ld\n",longVal);
        

        /* free allocated arrays */      
        free(units);
        free(unitsPercent);
    
        /* delete handle */
        codes_handle_delete(h);
        
        cnt++;
    }
    
    fclose(in);
    return 0;
}