/*

 * Copyright (c) Meta Platforms, Inc. and affiliates.

 * All rights reserved.

 *

 * This source code is licensed under both the BSD-style license (found in the

 * LICENSE file in the root directory of this source tree) and the GPLv2 (found

 * in the COPYING file in the root directory of this source tree).

 * You may select, at your option, one of the above-listed licenses.

 */

/**

 * This fuzz target attempts to decompress the fuzzed data with the simple

 * decompression function to ensure the decompressor never crashes.

 */

#include <stddef.h>

#include <stdlib.h>

#include <stdio.h>

#define ZSTD_STATIC_LINKING_ONLY

#include "fuzz_helpers.h"

#include "zstd.h"

#include "fuzz_data_producer.h"

static ZSTD_DCtx *dctx = NULL;

int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)

{

    /* Give a random portion of src data to the producer, to use for

    parameter generation. The rest will be used for (de)compression */

    FUZZ_dataProducer_t *producer = FUZZ_dataProducer_create(src, size);

    size = FUZZ_dataProducer_reserveDataPrefix(producer);

    if (!dctx) {

        dctx = ZSTD_createDCtx();

        FUZZ_ASSERT(dctx);

    }

    {

        size_t const bufSize = FUZZ_dataProducer_uint32Range(producer, 0, 10 * size);

        void *rBuf = FUZZ_malloc(bufSize);

        size_t const dSize = ZSTD_decompressDCtx(dctx, rBuf, bufSize, src, size);

        if (!ZSTD_isError(dSize)) {

            /* If decompression was successful, the content size from the frame header(s) should be valid. */

            unsigned long long const expectedSize = ZSTD_findDecompressedSize(src, size);

            FUZZ_ASSERT(expectedSize != ZSTD_CONTENTSIZE_ERROR);

            FUZZ_ASSERT(expectedSize == ZSTD_CONTENTSIZE_UNKNOWN || expectedSize == dSize);

        }

        free(rBuf);

    }

    FUZZ_dataProducer_free(producer);

#ifndef STATEFUL_FUZZING

    ZSTD_freeDCtx(dctx); dctx = NULL;

#endif

    return 0;

}