/**

 * 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"

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 = FUZZ_dataProducer_remainingBytes(producer);

    size_t const dstCapacity = FUZZ_getRange_from_uint32(dstCapacitySeed, 0, 4 * size);

    size_t const smallDictSize = size + 1;

    size_t const largeDictSize = 64 * 1024 - 1;

    size_t const dictSize = MAX(smallDictSize, largeDictSize);

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

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

    char* const largeDict = dict;

    char* const dataAfterDict = dict + dictSize;

    char* const smallDict = dataAfterDict - smallDictSize;

    FUZZ_ASSERT(dst);

    FUZZ_ASSERT(dict);

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

    memset(dict, 0, dictSize);

    memcpy(dataAfterDict, data, size);

    /* Decompress using each possible dictionary configuration. */

    /* No dictionary. */

    LZ4_decompress_safe_usingDict((char const*)data, dst, size,

                                  dstCapacity, NULL, 0);

    /* Small external dictionary. */

    LZ4_decompress_safe_usingDict((char const*)data, dst, size,

                                  dstCapacity, smallDict, smallDictSize);

    /* Large external dictionary. */

    LZ4_decompress_safe_usingDict((char const*)data, dst, size,

                                  dstCapacity, largeDict, largeDictSize);

    /* Small prefix. */

    LZ4_decompress_safe_usingDict((char const*)dataAfterDict, dst, size,

                                  dstCapacity, smallDict, smallDictSize);

    /* Large prefix. */

    LZ4_decompress_safe_usingDict((char const*)dataAfterDict, dst, size,

                                  dstCapacity, largeDict, largeDictSize);

    /* Partial decompression. */

    LZ4_decompress_safe_partial((char const*)data, dst, size,

                                dstCapacity, dstCapacity);

    /* Partial decompression using each possible dictionary configuration. */

    /* Partial decompression with no dictionary. */

    LZ4_decompress_safe_partial_usingDict((char const*)data, dst, size,

                                  dstCapacity, dstCapacity, NULL, 0);

    /* Partial decompression with small external dictionary. */

    LZ4_decompress_safe_partial_usingDict((char const*)data, dst, size,

                                  dstCapacity, dstCapacity, smallDict, smallDictSize);

    /* Partial decompression with large external dictionary. */

    LZ4_decompress_safe_partial_usingDict((char const*)data, dst, size,

                                  dstCapacity, dstCapacity, largeDict, largeDictSize);

    /* Partial decompression with small prefix. */

    LZ4_decompress_safe_partial_usingDict((char const*)dataAfterDict, dst, size,

                                  dstCapacity, dstCapacity, smallDict, smallDictSize);

    /* Partial decompression with large prefix. */

    LZ4_decompress_safe_partial_usingDict((char const*)dataAfterDict, dst, size,

                                  dstCapacity, dstCapacity, largeDict, largeDictSize);

    free(dst);

    free(dict);

    FUZZ_dataProducer_free(producer);

    return 0;

}