Contents

/*
 * Copyright 2016-2017 Uber Technologies, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/** @file
 * @brief stdin/stdout filter that converts from integer H3 indexes to
 * k-rings
 *
 *  usage: `kRing [k]`
 *
 *  The program reads H3 indexes from stdin until EOF and outputs
 *  the H3 indexes within k-ring `k` to stdout.
 */

#include <stdio.h>
#include <stdlib.h>
#include "algos.h"
#include "h3Index.h"
#include "stackAlloc.h"
#include "utility.h"

void doCell(H3Index h, int k) {
    int maxSize = H3_EXPORT(maxKringSize)(k);
    H3Index* rings = calloc(maxSize, sizeof(H3Index));
    H3_EXPORT(kRing)(h, k, rings);

    for (int i = 0; i < maxSize; i++) {
        if (rings[i] != 0) {
            h3Println(rings[i]);
        }
    }

    free(rings);
}

int main(int argc, char* argv[]) {
    // check command line args
    if (argc != 2) {
        fprintf(stderr, "usage: %s [k]\n", argv[0]);
        exit(1);
    }

    int k = 0;
    if (argc > 1) {
        if (!sscanf(argv[1], "%d", &k)) error("k must be an integer");
    }

    // process the indexes on stdin
    char buff[BUFF_SIZE];
    while (1) {
        // get an index from stdin
        if (!fgets(buff, BUFF_SIZE, stdin)) {
            if (feof(stdin))
                break;
            else
                error("reading H3 index from stdin");
        }

        H3Index h3 = H3_EXPORT(stringToH3)(buff);
        doCell(h3, k);
    }
}

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
h3-3.4.0	ext/h3/src/src/apps/filters/kRing.c
h3-3.3.1	ext/h3/src/src/apps/filters/kRing.c