Description
This example shows: how to copy a GRIB message in memory
Source code
grib_copy_message.f90
! (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. ! ! ! Description: how to copy a GRIB message in memory ! ! program copy use eccodes implicit none integer :: err, centre integer(kind=kindOfSize) :: byte_size integer :: infile,outfile integer :: igrib_in integer :: igrib_out character(len=1), dimension(:), allocatable :: message character(len=32) :: product_kind call codes_open_file(infile,'../../data/constant_field.grib1','r') call codes_open_file(outfile,'out.copy.grib1','w') ! A new GRIB message is loaded from file ! igrib_in is the GRIB id to be used in subsequent calls call codes_grib_new_from_file(infile, igrib_in) call codes_get_message_size(igrib_in, byte_size) allocate(message(byte_size), stat=err) call codes_copy_message(igrib_in, message) call codes_new_from_message(igrib_out, message) call codes_get(igrib_out, 'kindOfProduct', product_kind) write(*,*) 'kindOfProduct=',product_kind centre=80 call codes_set(igrib_out, 'centre', centre) ! Write message to a file call codes_write(igrib_out, outfile) call codes_release(igrib_out) call codes_release(igrib_in) call codes_close_file(infile) call codes_close_file(outfile) deallocate(message) end program copy
grib_copy_message.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_copy_message * * Description: How to copy a GRIB message in memory * */ #include <stdio.h> #include "eccodes.h" #include <assert.h> static void usage(const char *prog) { fprintf(stderr,"Usage is: %s input_file ouput_file\n", prog); } int main(int argc, char *argv[]) { FILE *in = NULL; codes_handle *source_handle = NULL; int err = 0; if (argc != 3) { usage(argv[0]); return 1; } in = fopen(argv[1],"r"); if (!in) { perror("ERROR: unable to input file"); return 1; } /* loop over the GRIB messages in the source */ while ((source_handle = codes_handle_new_from_file(0, in, PRODUCT_GRIB, &err))!=NULL) { size_t totalLength = 0, size = 0; const void* buffer = NULL; codes_handle* new_handle = NULL; CODES_CHECK(codes_get_message_size(source_handle,&totalLength),0); buffer=(unsigned char*)malloc(totalLength*sizeof(char)); CODES_CHECK(codes_get_message(source_handle, &buffer, &size),0); assert(size == totalLength); new_handle = codes_handle_new_from_message(0, buffer, totalLength); if (new_handle == NULL) { perror("ERROR: could not create GRIB handle from message"); return 1; } CODES_CHECK(codes_set_long(new_handle, "hour", 18),0); CODES_CHECK(codes_write_message(new_handle, argv[2], "w"),0); codes_handle_delete(new_handle); codes_handle_delete(source_handle); } fclose(in); return 0; }