eccodes/examples/C/grib_keys_iterator.c

98 lines
2.7 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: grib_keys_iterator
*
* Description:
* Example on how to use keys_iterator functions and the
* codes_keys_iterator structure to get all the available
* keys in a GRIB message.
*
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "eccodes.h"
#define MAX_VAL_LEN 1024
static void usage(char* progname);
int main(int argc, char* argv[])
{
/* to skip read only and computed keys
unsigned long key_iterator_filter_flags=CODES_KEYS_ITERATOR_SKIP_READ_ONLY |
CODES_KEYS_ITERATOR_SKIP_COMPUTED;
*/
unsigned long key_iterator_filter_flags = CODES_KEYS_ITERATOR_ALL_KEYS |
CODES_KEYS_ITERATOR_SKIP_DUPLICATES;
/* choose a namespace. E.g. "ls", "time", "parameter", "geography", "statistics" */
const char* name_space = "ls";
/* name_space=NULL to get all the keys */
/* char* name_space=0; */
FILE* f = NULL;
codes_handle* h = NULL;
int err = 0;
int msg_count = 0;
char value[MAX_VAL_LEN];
size_t vlen = MAX_VAL_LEN;
if (argc != 2) usage(argv[0]);
f = fopen(argv[1], "rb");
if (!f) {
perror(argv[1]);
exit(1);
}
while ((h = codes_handle_new_from_file(0, f, PRODUCT_GRIB, &err)) != NULL) {
codes_keys_iterator* kiter = NULL;
msg_count++;
printf("-- GRIB N. %d --\n", msg_count);
kiter = codes_keys_iterator_new(h, key_iterator_filter_flags, name_space);
if (!kiter) {
fprintf(stderr, "Error: Unable to create keys iterator\n");
exit(1);
}
while (codes_keys_iterator_next(kiter)) {
const char* name = codes_keys_iterator_get_name(kiter);
vlen = MAX_VAL_LEN;
memset(value, 0, vlen);
CODES_CHECK(codes_get_string(h, name, value, &vlen), name);
printf("%s = %s\n", name, value);
/* alternative way of getting the string value */
CODES_CHECK(codes_keys_iterator_get_string(kiter, value, &vlen), 0);
}
codes_keys_iterator_delete(kiter);
codes_handle_delete(h);
}
fclose(f);
return 0;
}
static void usage(char* progname)
{
printf("\nUsage: %s grib_file\n", progname);
exit(1);
}