Description

This example shows: how to create a new BUFR message by cloning an existing message.

Source code

bufr_clone.f90
! 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.
!
!  FORTRAN 90 implementation: bufr_clone
!
!  Description: how to create a new BUFR message by cloning
!               an existing message.
!
!
program bufr_clone
  use eccodes
  implicit none
  integer       :: i,iret
  integer       :: infile,outfile
  integer       :: ibufr_in
  integer       :: ibufr_out

  ! Open source file
  call codes_open_file(infile,'../../data/bufr/syno_multi.bufr','r')

  ! Open target file
  call codes_open_file(outfile,'bufr_clone_test_f.clone.bufr','w')

  ! The first bufr message is loaded from file,
  ! ibufr is the bufr id to be used in subsequent calls
  call codes_bufr_new_from_file(infile,ibufr_in,iret)

  ! Create several clones of this message and alter them
  ! in different ways
  do i=1,3

    ! Clone the current handle
    call codes_clone(ibufr_in, ibufr_out)

    ! This is the place where you may wish to modify the clone
    ! E.g. we change the bufrHeaderCentre
    call codes_set(ibufr_out,'bufrHeaderCentre',222)

    ! Write cloned messages to a file
    call codes_write(ibufr_out,outfile)

    ! Release the clone's handle
    call codes_release(ibufr_out)
  end do

  ! Release the original handle
  call codes_release(ibufr_in)

  call codes_close_file(infile)
  call codes_close_file(outfile)

end program bufr_clone
bufr_clone.py
# 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.
#

#
# Python implementation: bufr_clone
#
# Description: how to create a new BUFR message by cloning
# an existing message.
#

from __future__ import absolute_import
import sys
import traceback

from eccodes import *

INPUT = '../../data/bufr/syno_1.bufr'
OUTPUT = 'bufr_clone_test_p.clone.bufr'
VERBOSE = 1  # verbose error reporting


def example():
    # open BUFR file
    fin = open(INPUT, 'rb')

    # open output BUFR file
    fout = open(OUTPUT, 'wb')

    # get handle for message
    bufr = codes_bufr_new_from_file(fin)

    # create several clones of this message and alter them
    # in different ways
    for centre in range(0, 3):
        # clone the message
        clone_id = codes_clone(bufr)

        # this is the place where you may wish to modify the clone
        codes_set(clone_id, 'bufrHeaderCentre', centre)

        # write the cloned message to a file
        codes_write(clone_id, fout)

        # release the clone's handle
        codes_release(clone_id)

    # release the source's handle
    codes_release(bufr)

    fin.close()
    fout.close()


def main():
    try:
        example()
    except CodesInternalError as err:
        if VERBOSE:
            traceback.print_exc(file=sys.stderr)
        else:
            sys.stderr.write(err.msg + '\n')

        return 1


if __name__ == "__main__":
    sys.exit(main())
bufr_clone.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_clone
 *
 * Description: how to create new BUFR messages 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;

    /* message handle. Required in all the ecCodes calls acting on a message.*/
    codes_handle *source_handle = NULL;

    const void *buffer = NULL;
    size_t size = 0;
    int i, err = 0;

    if (argc != 3) {
        usage(argv[0]);
        return 1;
    }

    in = fopen(argv[1],"rb");
    out = fopen(argv[2],"wb");

    /* open input and output */
    if (!in || !out) {
        perror("ERROR: unable to open files");
        if (out) fclose(out);
        if (in) fclose(in);
        return 1;
    }

    /* create a handle for the first message */
    source_handle = codes_handle_new_from_file(NULL, in, PRODUCT_BUFR, &err);

    if (source_handle == NULL) {
        perror("ERROR: could not create handle for message");
        fclose(out);
        fclose(in);
        return 1;
    }

    /* create several clones of this message and alter them
       in different ways */

    for(i=0; i < 3; i++) {

        /* clone the current handle */
        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. we change the bufrHeaderCentre */

        CODES_CHECK(codes_set_long(clone_handle, "bufrHeaderCentre", 222),0);

        /* 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("ERROR: could not write message to file");
            return 1;
        }

        /* release the clone's handle */
        codes_handle_delete(clone_handle);
    }

    /* release the source's handle */
    codes_handle_delete(source_handle);

    fclose(out);
    fclose(in);

    return 0;
}