#include <stdio.h>

#include "grib_api.h"

void usage(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;

	grib_handle *source_handle = NULL;
	grib_handle *clone_handle = NULL;
	const void *buffer = NULL;
	size_t size = 0;
	int err = 0;

	/* check number of arguments */
	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 input files");
		return 1;
	}

	/* loop over the messages in the source grib and clone them */
	while ((source_handle = grib_handle_new_from_file(0,in,&err))!=NULL) {
		clone_handle = grib_handle_clone(source_handle);

		if (clone_handle == NULL) {
			perror("ERROR: coult not clone field");
			return 1;
		}

		/* get the coded message in a buffer */
		GRIB_CHECK(grib_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;
		}
	}

	grib_handle_delete(source_handle);
	grib_handle_delete(clone_handle);

	fclose(out);
	fclose(in);

	return 0;
}