/**

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

 * decompression function to ensure the decompressor never crashes.

 */

#include <stddef.h>

#include <stdint.h>

#include <stdlib.h>

#include <string.h>

#include "fuzz_helpers.h"

#include "fuzz_data_producer.h"

#include "lz4.h"

#define LZ4F_STATIC_LINKING_ONLY

#include "lz4frame.h"

#include "lz4_helpers.h"

static void decompress(LZ4F_dctx* dctx, void* dst, size_t dstCapacity,

                       const void* src, size_t srcSize,

                       const void* dict, size_t dictSize,

                       const LZ4F_decompressOptions_t* opts)

{

    LZ4F_resetDecompressionContext(dctx);

    if (dictSize == 0)

        LZ4F_decompress(dctx, dst, &dstCapacity, src, &srcSize, opts);

    else

        LZ4F_decompress_usingDict(dctx, dst, &dstCapacity, src, &srcSize,

                                  dict, dictSize, opts);

}

int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)

{

    FUZZ_dataProducer_t *producer = FUZZ_dataProducer_create(data, size);

    size_t const dstCapacitySeed = FUZZ_dataProducer_retrieve32(producer);

    size_t const dictSizeSeed = FUZZ_dataProducer_retrieve32(producer);

    size = FUZZ_dataProducer_remainingBytes(producer);

    size_t const dstCapacity = FUZZ_getRange_from_uint32(

      dstCapacitySeed, 0, 4 * size);

    size_t const largeDictSize = 64 * 1024;

    size_t const dictSize = FUZZ_getRange_from_uint32(

      dictSizeSeed, 0, largeDictSize);

    char* const dst = (char*)malloc(dstCapacity);

    char* const dict = (char*)malloc(dictSize);

    LZ4F_decompressOptions_t opts;

    LZ4F_dctx* dctx;

    LZ4F_createDecompressionContext(&dctx, LZ4F_VERSION);

    FUZZ_ASSERT(dctx);

    FUZZ_ASSERT(dst);

    FUZZ_ASSERT(dict);

    /* Prepare the dictionary. The data doesn't matter for decompression. */

    memset(dict, 0, dictSize);

    /* Decompress using multiple configurations. */

    memset(&opts, 0, sizeof(opts));

    opts.stableDst = 0;

    decompress(dctx, dst, dstCapacity, data, size, NULL, 0, &opts);

    opts.stableDst = 1;

    decompress(dctx, dst, dstCapacity, data, size, NULL, 0, &opts);

    opts.stableDst = 0;

    decompress(dctx, dst, dstCapacity, data, size, dict, dictSize, &opts);

    opts.stableDst = 1;

    decompress(dctx, dst, dstCapacity, data, size, dict, dictSize, &opts);

    LZ4F_freeDecompressionContext(dctx);

    free(dst);

    free(dict);

    FUZZ_dataProducer_free(producer);

    return 0;

}