eccodes/examples/C/grib_clone.c

82 lines
2.0 KiB
C

/*
* Copyright 2005-2018 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_clone
*
* Description: How to create a new GRIB message by cloning
* an existing message.
*
*/
#include <stdio.h>
#include "eccodes.h"
static void usage(const char *app)
{
fprintf(stderr,"Usage is: %s input_file ouput_file\n", app);
}
int main(int argc, char *argv[])
{
FILE *in = NULL;
FILE *out = NULL;
codes_handle *source_handle = NULL;
const void *buffer = NULL;
size_t size = 0;
int err = 0;
if (argc != 3) {
usage(argv[0]);
return 1;
}
in = fopen(argv[1],"r");
out = fopen(argv[2],"w");
if (!in || !out) {
perror("ERROR: unable to open files");
fclose(out);
fclose(in);
return 1;
}
/* loop over the messages in the source grib and clone them */
while ((source_handle = codes_handle_new_from_file(0, in, PRODUCT_GRIB, &err))!=NULL)
{
codes_handle *clone_handle = codes_handle_clone(source_handle);
if (clone_handle == NULL) {
perror("ERROR: could not clone field");
return 1;
}
/* This is the place where you may wish to modify the clone */
/* E.g.
CODES_CHECK(codes_set_long(clone_handle, "centre", 250),0);
etc...
*/
/* get the coded message in a buffer */
CODES_CHECK(codes_get_message(clone_handle,&buffer,&size),0);
/* write the buffer to a file */
if(fwrite(buffer,1,size,out) != size) {
perror(argv[1]);
return 1;
}
codes_handle_delete(clone_handle);
codes_handle_delete(source_handle);
}
fclose(out);
fclose(in);
return 0;
}