/*

 * Copyright 2021 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 Fuzzer program for cellToParent and cellToChildren functions

 */

#include "aflHarness.h"

#include "h3api.h"

#include "utility.h"

#define MAX_CHILDREN_DIFF 10

typedef struct {

    H3Index index;

    int parentRes;

    int childRes;

} inputArgs;

int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {

    if (size < sizeof(inputArgs)) {

        return 0;

    }

    const inputArgs *args = (const inputArgs *)data;

    H3Index parent;

    H3_EXPORT(cellToParent)(args->index, args->parentRes, &parent);

    H3Index out;

    H3_EXPORT(cellToCenterChild)(args->index, args->childRes, &out);

    // Check for underflow before using args->childRes in subtraction.

    // getResolution will always produce outputs in the range of [0, 15], never

    // negative.

    if (args->childRes >= INT32_MIN + H3_EXPORT(getResolution)(args->index)) {

        int resDiff = args->childRes - H3_EXPORT(getResolution)(args->index);

        if (resDiff < MAX_CHILDREN_DIFF) {

            int64_t childrenSize;

            H3Error err = H3_EXPORT(cellToChildrenSize)(

                args->index, args->childRes, &childrenSize);

            if (!err) {

                H3Index *children = calloc(childrenSize, sizeof(H3Index));

                H3_EXPORT(cellToChildren)

                (args->index, args->childRes, children);

                free(children);

            }

        }

    }

    return 0;

}

AFL_HARNESS_MAIN(sizeof(inputArgs));