eccodes/tests/grib_multi_from_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.
 */

/*
 * test: reading GRIB2 multi fields messages from memory
 */

#include "grib_api_internal.h"
#include <assert.h>


static void usage(const char* prog)
{
    fprintf(stderr, "usage: %s [-m] file.grib\n", prog);
    exit(1);
}

int main(int argc, char* argv[])
{
    struct stat finfo;
    char shortName[20] = {
        0,
    };
    size_t len;
    grib_handle* h = NULL;
    size_t fsize;
    unsigned char* data = NULL;
    unsigned char* p    = NULL;
    void* pdata         = NULL;
    int error           = 0;
    int count           = 0;
    char* filename      = NULL;
    FILE* f             = NULL;
    long level          = 0;
    grib_context* c     = grib_context_get_default();
    int multi_support   = 0;

    if (argc == 3 && !strcmp(argv[1], "-m")) {
        grib_multi_support_on(c);
        multi_support = 1;
        filename = argv[2];
    }
    else if (argc == 2)
        filename = argv[1];
    else
        usage(argv[0]);

    assert(filename);
    f = fopen(filename, "rb");
    if (!f) {
        perror(filename);
        exit(1);
    }

    stat(filename, &finfo);
    fsize = finfo.st_size;

    data = (unsigned char*)malloc(fsize);
    p    = data;

    if (!data) {
        fprintf(stderr, "unable to allocate %ld bytes\n", (long)fsize);
        exit(1);
    }

    if (fread(data, 1, fsize, f) != fsize) {
        perror(filename);
        exit(1);
    }
    fclose(f);
    pdata = &data;

    while ((h = grib_handle_new_from_multi_message(c, (void**)pdata, &fsize, &error)) != NULL) {
        count++;
        len = 20;
        GRIB_CHECK(grib_get_string(h, "shortName", shortName, &len), "shortName");
        GRIB_CHECK(grib_get_long(h, "level", &level), "level");
        printf("%d %s %ld\n", count, shortName, level);
        if (!multi_support) {
            grib_context_free(c, h->buffer->data); /* See grib_handle_delete and grib_buffer_delete */
        }
        grib_handle_delete(h);
    }

    free(p);

    return 0;
}