/**

 * 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 performs a zstd round-trip test (compress & decompress),

 * compares the result with the original, and calls abort() on corruption.

 */

#define ZSTD_STATIC_LINKING_ONLY

#include <stddef.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include "fuzz_helpers.h"

#include "zstd.h"

#include "zstd_helpers.h"

#include "fuzz_data_producer.h"

#include "fuzz_third_party_seq_prod.h"

static ZSTD_CCtx *cctx = NULL;

static ZSTD_DCtx *dctx = NULL;

static void* cBuf = NULL;

static void* rBuf = NULL;

static size_t bufSize = 0;

static size_t roundTripTest(void *result, size_t resultCapacity,

                            void *compressed, size_t compressedCapacity,

                            const void *src, size_t srcSize,

                            int cLevel)

{

    ZSTD_parameters const params = ZSTD_getParams(cLevel, srcSize, 0);

    size_t ret = ZSTD_compressBegin_advanced(cctx, NULL, 0, params, srcSize);

    FUZZ_ZASSERT(ret);

    ret = ZSTD_compressBlock(cctx, compressed, compressedCapacity, src, srcSize);

    FUZZ_ZASSERT(ret);

    if (ret == 0) {

        FUZZ_ASSERT(resultCapacity >= srcSize);

        if (srcSize > 0) {

            memcpy(result, src, srcSize);

        }

        return srcSize;

    }

    ZSTD_decompressBegin(dctx);

    return ZSTD_decompressBlock(dctx, result, resultCapacity, compressed, ret);

}

int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)

{

    FUZZ_SEQ_PROD_SETUP();

    /* 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);

    int const cLevel = FUZZ_dataProducer_int32Range(producer, kMinClevel, kMaxClevel);

    size_t neededBufSize = size;

    if (size > ZSTD_BLOCKSIZE_MAX)

        size = ZSTD_BLOCKSIZE_MAX;

    /* Allocate all buffers and contexts if not already allocated */

    if (neededBufSize > bufSize || !cBuf || !rBuf) {

        free(cBuf);

        free(rBuf);

        cBuf = FUZZ_malloc(neededBufSize);

        rBuf = FUZZ_malloc(neededBufSize);

        bufSize = neededBufSize;

    }

    if (!cctx) {

        cctx = ZSTD_createCCtx();

        FUZZ_ASSERT(cctx);

    }

    if (!dctx) {

        dctx = ZSTD_createDCtx();

        FUZZ_ASSERT(dctx);

    }

    {

        size_t const result =

            roundTripTest(rBuf, neededBufSize, cBuf, neededBufSize, src, size,

              cLevel);

        FUZZ_ZASSERT(result);

        FUZZ_ASSERT_MSG(result == size, "Incorrect regenerated size");

        FUZZ_ASSERT_MSG(!FUZZ_memcmp(src, rBuf, size), "Corruption!");

    }

    FUZZ_dataProducer_free(producer);

#ifndef STATEFUL_FUZZING

    ZSTD_freeCCtx(cctx); cctx = NULL;

    ZSTD_freeDCtx(dctx); dctx = NULL;

#endif

    FUZZ_SEQ_PROD_TEARDOWN();

    return 0;

}