eccodes/examples/C/large_grib1.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.
 */

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "eccodes.h"

/* See JIRA issue GRIB-361 */
int main(void)
{
    const int ni = 2880;
    const int nj = 2880;
    size_t numbytes = 0;
    double* values;
    int i                = 0;
    codes_handle* h      = NULL;
    const char* filename = "bigfile.grib";

#ifndef ECCODES_ON_WINDOWS
    unsigned int seed = time(NULL);
#endif

    numbytes = ni * nj * sizeof(double);
    values = (double*)malloc(numbytes);
    if (!values) {
        fprintf(stderr, "Malloc failed - requested %zu bytes\n", numbytes);
        return 1;
    }

    for (i = 0; i < ni * nj; i++) {
        #ifndef ECCODES_ON_WINDOWS
            double r  = rand_r(&seed) * 1.0 / RAND_MAX;
        #else
            double r  = rand() * 1.0 / RAND_MAX;
        #endif
        values[i] = r;
    }

    h = codes_grib_handle_new_from_samples(0, "GRIB1");

    CODES_CHECK(codes_set_long(h, "Ni", ni), 0);
    CODES_CHECK(codes_set_long(h, "Nj", nj), 0);
    CODES_CHECK(codes_set_long(h, "centre", 86), 0);
    CODES_CHECK(codes_set_long(h, "process", 100), 0);
    CODES_CHECK(codes_set_long(h, "indicatorOfTypeOfLevel", 105), 0);
    CODES_CHECK(codes_set_long(h, "level", 2), 0);
    CODES_CHECK(codes_set_long(h, "indicatorOfParameter", 1), 0);
    CODES_CHECK(codes_set_long(h, "table2Version", 1), 0);
    CODES_CHECK(codes_set_long(h, "dataDate", 20130424), 0);
    CODES_CHECK(codes_set_long(h, "dataTime", 0), 0);
    CODES_CHECK(codes_set_long(h, "startStep", 0), 0);
    CODES_CHECK(codes_set_long(h, "endStep", 0), 0);

    CODES_CHECK(codes_set_long(h, "bitmapPresent", 1), 0);

    CODES_CHECK(codes_set_double(h, "iDirectionIncrementInDegrees", 0.125), 0);
    CODES_CHECK(codes_set_double(h, "jDirectionIncrementInDegrees", 0.125), 0);
    CODES_CHECK(codes_set_long(h, "iScansNegatively", 0), 0);
    CODES_CHECK(codes_set_long(h, "jScansPositively", 1), 0);

    CODES_CHECK(codes_set_double(h, "latitudeOfFirstGridPointInDegrees", -90), 0);
    CODES_CHECK(codes_set_double(h, "latitudeOfLastGridPointInDegrees", 90), 0);
    CODES_CHECK(codes_set_double(h, "longitudeOfFirstGridPointInDegrees", -180), 0);
    CODES_CHECK(codes_set_double(h, "longitudeOfLastGridPointInDegrees", 180), 0);

    CODES_CHECK(codes_set_double_array(h, "values", values, ni * nj), 0);

    codes_write_message(h, filename, "w");

    codes_handle_delete(h);
    free(values);

    return 0;
}