eccodes/examples/C/grib_multi.c

80 lines
2.6 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: grib_multi
*
* Description: How to decode GRIB2 multi-field messages.
* Try to turn the multi support on and off to
* see the difference. Default is OFF.
* For all the tools (e.g., grib_ls etc) multi support is ON.
*/
#include <stdio.h>
#include <assert.h>
#include "eccodes.h"
int main(int argc, char** argv)
{
int err = 0;
long parameterCategory = 0, parameterNumber = 0, discipline = 0;
FILE* in = NULL;
const char* filename = "../../data/multi.grib2";
codes_handle* h = NULL;
int mcount = 0;
/* turn off support for GRIB2 multi-field messages */
codes_grib_multi_support_off(NULL);
/* turn on support for GRIB2 multi-field messages */
codes_grib_multi_support_on(NULL);
in = fopen(filename, "rb");
if (!in) {
fprintf(stderr, "Error: unable to open file %s\n", filename);
return 1;
}
CODES_CHECK(codes_count_in_file(NULL, in, &mcount), 0);
assert(mcount == 56);
printf("count_in_file counted %d messages\n", mcount);
mcount = 0;
CODES_CHECK(codes_count_in_filename(NULL, filename, &mcount), 0);
assert(mcount == 56);
printf("count_in_filename counted %d messages\n", mcount);
mcount = 0;
while ((h = codes_handle_new_from_file(0, in, PRODUCT_GRIB, &err)) != NULL) {
CODES_CHECK(err, 0);
++mcount;
CODES_CHECK(codes_get_long(h, "discipline", &discipline), 0);
printf("discipline=%ld\n", discipline);
CODES_CHECK(codes_get_long(h, "parameterCategory", &parameterCategory), 0);
printf("parameterCategory=%ld\n", parameterCategory);
CODES_CHECK(codes_get_long(h, "parameterNumber", &parameterNumber), 0);
printf("parameterNumber=%ld\n", parameterNumber);
if (discipline == 0 && parameterCategory == 2) {
if (parameterNumber == 2) printf("-------- u -------\n");
if (parameterNumber == 3) printf("-------- v -------\n");
}
codes_handle_delete(h);
}
assert(mcount == 56);
printf("codes_handle_new_from_file counted %d messages\n", mcount);
fclose(in);
return 0;
}