eccodes/examples/C/bufr_subset.c

102 lines
3.4 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_subset
*
* Description: how to read data values from a given subset of a BUFR message.
*
*/
#include "eccodes.h"
#include <assert.h>
int main(int argc, char* argv[])
{
char key[200] = {0,};
FILE* in = NULL;
/* message handle. Required in all the eccodes calls acting on a message.*/
codes_handle* h = NULL;
long numberOfSubsets = 0;
long longVal;
double doubleVal;
size_t stringLen;
char stringVal[100] = {0,};
int i, err = 0;
int cnt = 0, ktype = 0;
const char* infile = "../../data/bufr/synop_multi_subset.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 all the descriptors i.e. unpack the data values */
CODES_CHECK(codes_set_long(h, "unpack", 1), 0);
/* find out the number of subsets */
CODES_CHECK(codes_get_long(h, "numberOfSubsets", &numberOfSubsets), 0);
printf(" numberOfSubsets: %ld\n", numberOfSubsets);
/* loop over the subsets */
for (i = 1; i <= numberOfSubsets; i++) {
snprintf(key, sizeof(key), "/subsetNumber=%d/blockNumber", i);
CODES_CHECK(codes_get_native_type(h, key, &ktype), 0);
/* printf("Type = %d\n", ktype); */
printf(" subsetNumber=%d", i);
/* read and print some data values */
CODES_CHECK(codes_get_long(h, key, &longVal), 0);
printf(" blockNumber=%ld", longVal);
snprintf(key, sizeof(key), "/subsetNumber=%d/stationNumber", i);
CODES_CHECK(codes_get_long(h, key, &longVal), 0);
printf(" stationNumber=%ld", longVal);
snprintf(key, sizeof(key), "/subsetNumber=%d/stationOrSiteName->units", i);
CODES_CHECK(codes_get_length(h, key, &stringLen), 0);
assert(stringLen == 10); /* should be "CCITT IA5" */
snprintf(key, sizeof(key), "/subsetNumber=%d/stationOrSiteName", i);
CODES_CHECK(codes_get_length(h, key, &stringLen), 0);
CODES_CHECK(codes_get_string(h, key, stringVal, &stringLen), 0);
assert(stringLen > 0 && stringLen < 17);
printf(" stationOrSiteName=\"%s\"", stringVal);
snprintf(key, sizeof(key), "/subsetNumber=%d/airTemperature", i);
CODES_CHECK(codes_get_double(h, key, &doubleVal), 0);
printf(" airTemperature=%g\n", doubleVal);
assert(doubleVal > 265 && doubleVal < 278);
}
/* delete handle */
codes_handle_delete(h);
cnt++;
}
fclose(in);
return 0;
}