eccodes/examples/C/bufr_get_keys.c

121 lines
3.7 KiB
C

/*
* (C) Copyright 2005- 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_get_keys
*
* Description: how to read values of different type of keys from 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;
long* descriptors = NULL;
double* values = NULL;
char* typicalDate = NULL;
long longVal;
double doubleVal;
size_t values_len = 0, desc_len = 0, len = 0;
int i, err = 0;
int cnt = 0;
const char* infile = "../../data/bufr/syno_multi.bufr";
in = fopen(infile, "rb");
if (!in) {
fprintf(stderr, "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) {
fprintf(stderr, "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);
/* read and print some data values */
/* long value */
CODES_CHECK(codes_get_long(h, "blockNumber", &longVal), 0);
printf(" blockNumber: %ld\n", longVal);
/* long value */
CODES_CHECK(codes_get_long(h, "stationNumber", &longVal), 0);
printf(" stationNumber: %ld\n", longVal);
/* double value */
CODES_CHECK(codes_get_double(h, "airTemperatureAt2M", &doubleVal), 0);
printf(" airTemperatureAt2M: %f\n", doubleVal);
/* ---- string value -----------------*/
/* get the size and allocate memory*/
CODES_CHECK(codes_get_length(h, "typicalDate", &len), 0);
typicalDate = (char*)malloc(len * sizeof(char));
/* get the values*/
codes_get_string(h, "typicalDate", typicalDate, &len);
printf(" typicalDate: %s\n", typicalDate);
/* ---- array of long ----------------*/
/* get the size and allocate memory*/
CODES_CHECK(codes_get_size(h, "bufrdcExpandedDescriptors", &desc_len), 0);
descriptors = (long*)malloc(desc_len * sizeof(long));
/* get the values */
CODES_CHECK(codes_get_long_array(h, "bufrdcExpandedDescriptors", descriptors, &desc_len), 0);
printf(" bufrdcExpandedDescriptors:\n");
for (i = 0; i < desc_len; i++) {
printf(" %ld\n", descriptors[i]);
}
/* ---- array of double ---------------*/
/* get the size and allocate memory*/
CODES_CHECK(codes_get_size(h, "numericValues", &values_len), 0);
values = (double*)malloc(values_len * sizeof(double));
/* get the values*/
CODES_CHECK(codes_get_double_array(h, "numericValues", values, &values_len), 0);
printf(" numericValues:\n");
for (i = 0; i < values_len; i++) {
printf(" %.10e\n", values[i]);
}
/* free allocated arrays */
free(descriptors);
free(values);
free(typicalDate);
/* delete handle */
codes_handle_delete(h);
cnt++;
}
fclose(in);
return 0;
}