/*

 *    Copyright (C) 2016-2026 Grok Image Compression Inc.

 *

 *    This source code is free software: you can redistribute it and/or  modify

 *    it under the terms of the GNU Affero General Public License, version 3,

 *    as published by the Free Software Foundation.

 *

 *    This source code is distributed in the hope that it will be useful,

 *    but WITHOUT ANY WARRANTY; without even the implied warranty of

 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *    GNU Affero General Public License for more details.

 *

 *    You should have received a copy of the GNU Affero General Public License

 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.

 *

 */

#include <climits>

#include <cstddef>

#include <cstdint>

#include <cstdio>

#include <cstdlib>

#include <cstring>

#include <unistd.h>

#include "grok.h"

extern "C" int LLVMFuzzerInitialize(int* argc, char*** argv);

extern "C" int LLVMFuzzerTestOneInput(const uint8_t* buf, size_t len);

static int temp_file_descriptor = -1;

static char temp_file_path[] = "/tmp/grk_mercury_fuzz_XXXXXX";

struct Initializer

{

  Initializer()

  {

    setenv("GRK_MERCURY", "1", 1);

    temp_file_descriptor = mkstemp(temp_file_path);

    grk_initialize(nullptr, 0, nullptr);

  }

};

int LLVMFuzzerInitialize(int* argc, char*** argv)

{

  static Initializer init;

  return 0;

}

int LLVMFuzzerTestOneInput(const uint8_t* buf, size_t len)

{

  grk_header_info headerInfo = {};

  grk_decompress_parameters parameters = {};

  // bound the decoded area so a huge declared canvas cannot OOM the fuzzer.

  // mercury still runs when this window covers the whole image (<=1024);

  // larger images fall back to the classic windowed decode.

  parameters.dw_x1 = 1024;

  parameters.dw_y1 = 1024;

  grk_object* codec = nullptr;

  grk_stream_params stream_params = {};

  if(temp_file_descriptor < 0)

    return 0;

  if(ftruncate(temp_file_descriptor, 0) != 0)

    return 0;

  if(lseek(temp_file_descriptor, 0, SEEK_SET) != 0)

    return 0;

  size_t written = 0;

  while(written < len)

  {

    ssize_t count = write(temp_file_descriptor, buf + written, len - written);

    if(count <= 0)

      return 0;

    written += (size_t)count;

  }

  strncpy(stream_params.file, temp_file_path, sizeof(stream_params.file) - 1);

  codec = grk_decompress_init(&stream_params, &parameters);

  if(!codec)

    goto cleanup;

  if(!grk_decompress_read_header(codec, &headerInfo))

    goto cleanup;

  if(!grk_decompress(codec, nullptr))

    goto cleanup;

cleanup:

  grk_object_unref(codec);

  return 0;

}