/**

 * This fuzz target performs a lz4 round-trip test (compress & decompress),

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

 */

#include <stddef.h>

#include <stdint.h>

#include <stdlib.h>

#include <string.h>

#include "fuzz_helpers.h"

#include "lz4.h"

#include "fuzz_data_producer.h"

int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)

{

    FUZZ_dataProducer_t *producer = FUZZ_dataProducer_create(data, size);

    size_t const partialCapacitySeed = FUZZ_dataProducer_retrieve32(producer);

    size = FUZZ_dataProducer_remainingBytes(producer);

    size_t const partialCapacity = FUZZ_getRange_from_uint32(partialCapacitySeed, 0, size);

    size_t const dstCapacity = LZ4_compressBound(size);

    size_t const largeSize = 64 * 1024 - 1;

    size_t const smallSize = 1024;

    char* const dstPlusLargePrefix = (char*)malloc(dstCapacity + largeSize);

    FUZZ_ASSERT(dstPlusLargePrefix);

    char* const dstPlusSmallPrefix = dstPlusLargePrefix + largeSize - smallSize;

    char* const largeDict = (char*)malloc(largeSize);

    FUZZ_ASSERT(largeDict);

    char* const smallDict = largeDict + largeSize - smallSize;

    char* const dst = dstPlusLargePrefix + largeSize;

    char* const rt = (char*)malloc(size);

    FUZZ_ASSERT(rt);

    /* Compression must succeed and round trip correctly. */

    int const dstSize = LZ4_compress_default((const char*)data, dst,

                                             size, dstCapacity);

    FUZZ_ASSERT(dstSize > 0);

    int const rtSize = LZ4_decompress_safe(dst, rt, dstSize, size);

    FUZZ_ASSERT_MSG(rtSize == size, "Incorrect size");

    FUZZ_ASSERT_MSG(!memcmp(data, rt, size), "Corruption!");

    /* Partial decompression must succeed. */

    {

        char* const partial = (char*)malloc(partialCapacity);

        FUZZ_ASSERT(partial);

        int const partialSize = LZ4_decompress_safe_partial(

                dst, partial, dstSize, partialCapacity, partialCapacity);

        FUZZ_ASSERT(partialSize >= 0);

        FUZZ_ASSERT_MSG(partialSize == partialCapacity, "Incorrect size");

        FUZZ_ASSERT_MSG(!memcmp(data, partial, partialSize), "Corruption!");

        free(partial);

    }

    /* Partial decompression using dict with no dict. */

    {

        char* const partial = (char*)malloc(partialCapacity);

        FUZZ_ASSERT(partial);

        int const partialSize = LZ4_decompress_safe_partial_usingDict(

                dst, partial, dstSize, partialCapacity, partialCapacity, NULL, 0);

        FUZZ_ASSERT(partialSize >= 0);

        FUZZ_ASSERT_MSG(partialSize == partialCapacity, "Incorrect size");

        FUZZ_ASSERT_MSG(!memcmp(data, partial, partialSize), "Corruption!");

        free(partial);

    }

    /* Partial decompression using dict with small prefix as dict */

    {

        char* const partial = (char*)malloc(partialCapacity);

        FUZZ_ASSERT(partial);

        int const partialSize = LZ4_decompress_safe_partial_usingDict(

                dst, partial, dstSize, partialCapacity, partialCapacity, dstPlusSmallPrefix, smallSize);

        FUZZ_ASSERT(partialSize >= 0);

        FUZZ_ASSERT_MSG(partialSize == partialCapacity, "Incorrect size");

        FUZZ_ASSERT_MSG(!memcmp(data, partial, partialSize), "Corruption!");

        free(partial);

    }

    /* Partial decompression using dict with large prefix as dict */

    {

        char* const partial = (char*)malloc(partialCapacity);

        FUZZ_ASSERT(partial);

        int const partialSize = LZ4_decompress_safe_partial_usingDict(

                dst, partial, dstSize, partialCapacity, partialCapacity, dstPlusLargePrefix, largeSize);

        FUZZ_ASSERT(partialSize >= 0);

        FUZZ_ASSERT_MSG(partialSize == partialCapacity, "Incorrect size");

        FUZZ_ASSERT_MSG(!memcmp(data, partial, partialSize), "Corruption!");

        free(partial);

    }

    /* Partial decompression using dict with small external dict */

    {

        char* const partial = (char*)malloc(partialCapacity);

        FUZZ_ASSERT(partial);

        int const partialSize = LZ4_decompress_safe_partial_usingDict(

                dst, partial, dstSize, partialCapacity, partialCapacity, smallDict, smallSize);

        FUZZ_ASSERT(partialSize >= 0);

        FUZZ_ASSERT_MSG(partialSize == partialCapacity, "Incorrect size");

        FUZZ_ASSERT_MSG(!memcmp(data, partial, partialSize), "Corruption!");

        free(partial);

    }

    /* Partial decompression using dict with large external dict */

    {

        char* const partial = (char*)malloc(partialCapacity);

        FUZZ_ASSERT(partial);

        int const partialSize = LZ4_decompress_safe_partial_usingDict(

                dst, partial, dstSize, partialCapacity, partialCapacity, largeDict, largeSize);

        FUZZ_ASSERT(partialSize >= 0);

        FUZZ_ASSERT_MSG(partialSize == partialCapacity, "Incorrect size");

        FUZZ_ASSERT_MSG(!memcmp(data, partial, partialSize), "Corruption!");

        free(partial);

    }

    free(dstPlusLargePrefix);

    free(largeDict);

    free(rt);

    FUZZ_dataProducer_free(producer);

    return 0;

}