// SPDX-License-Identifier: 0BSD

///////////////////////////////////////////////////////////////////////////////

//

/// \file       fuzz_encode_stream.c

/// \brief      Fuzz test program for .xz encoding

//

//  Authors:    Maksym Vatsyk

//              Lasse Collin

//

///////////////////////////////////////////////////////////////////////////////

#include <inttypes.h>

#include <stdlib.h>

#include <stdio.h>

#include "lzma.h"

#include "fuzz_common.h"

extern int

LLVMFuzzerTestOneInput(const uint8_t *inbuf, size_t inbuf_size)

{

  if (inbuf_size == 0) {

    fprintf(stderr, "no input data provided\n");

    return 0;

  }

  // Set the LZMA options based on the first input byte. The fuzzer

  // will learn through its mutational genetic algorithm with the

  // code coverage feedback that the first byte must be one of the

  // values with a switch case label. This allows us to have one fuzz

  // target cover many critical code paths so the fuzz resources can

  // be used efficiently.

  uint32_t preset_level;

  const uint8_t decider = inbuf[0];

  switch (decider) {

  case 0:

  case 1:

  case 5:

    preset_level = (uint32_t)decider;

    break;

  case 6:

    preset_level = 0 | LZMA_PRESET_EXTREME;

    break;

  case 7:

    preset_level = 3 | LZMA_PRESET_EXTREME;

    break;

  default:

    return 0;

  }

  // Initialize lzma_options with the above preset level

  lzma_options_lzma opt_lzma;

  if (lzma_lzma_preset(&opt_lzma, preset_level)){

    fprintf(stderr, "lzma_lzma_preset() failed\n");

    abort();

  }

  // Set the filter chain as only LZMA2.

  lzma_filter filters[2] = {

    {

      .id = LZMA_FILTER_LZMA2,

      .options = &opt_lzma,

    }, {

      .id = LZMA_VLI_UNKNOWN,

    }

  };

  // initialize empty LZMA stream

  lzma_stream strm = LZMA_STREAM_INIT;

  // Initialize the stream encoder using the above

  // stream, filter chain and CRC64.

  lzma_ret ret = lzma_stream_encoder(&strm, filters, LZMA_CHECK_CRC64);

  if (ret != LZMA_OK) {

    fprintf(stderr, "lzma_stream_encoder() failed (%d)\n", ret);

    abort();

  }

  fuzz_code(&strm, inbuf  + 1, inbuf_size - 1);

  // Free the allocated memory.

  lzma_end(&strm);

  return 0;

}