/**

 *

 * @copyright Copyright (c) 2019 Joachim Bauch <mail@joachim-bauch.de>

 *

 * @license GNU GPL version 3 or any later version

 *

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

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * This program 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 General Public License for more details.

 *

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

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

 *

 */

#include <stdint.h>

#include <stdlib.h>

#include <string.h>

#include "Lzma2Dec.h"

#include "common-alloc.h"

static const size_t kBufferSize = 8192;

static const size_t kMaxDictionarySize = 32 * 1024 * 1024;

// Limit maximum size to avoid running into timeouts with too large data.

static const size_t kMaxInputSize = 100 * 1024;

// Copied from sdk/C/Lzma2Dec.c

#define LZMA2_DIC_SIZE_FROM_PROP(p) \

    (((UInt32)2 | ((p) & 1)) << ((p) / 2 + 11))

static bool GetDictionarySize(Byte prop, size_t* size) {

  if (prop > 40) {

    return false;

  }

  *size = (prop == 40)

      ? 0xFFFFFFFF

      : LZMA2_DIC_SIZE_FROM_PROP(prop);

  return true;

}

extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {

  if (size < 1 || size > kMaxInputSize) {

    return 0;

  }

  size_t dictionarySize;

  if (!GetDictionarySize(data[0], &dictionarySize)) {

    return 0;

  }

  // Avoid using too much memory.

  if (dictionarySize > kMaxDictionarySize) {

    return 0;

  }

  CLzma2Dec dec;

  Lzma2Dec_Construct(&dec);

  if (Lzma2Dec_Allocate(&dec, data[0], &CommonAlloc) != SZ_OK) {

    return 0;

  }

  data += 1;

  size -= 1;

  Lzma2Dec_Init(&dec);

  while (size > 0) {

    Byte buf[kBufferSize];

    SRes res;

    SizeT srcLen = size;

    SizeT destLen = kBufferSize;

    ELzmaStatus status;

    res = Lzma2Dec_DecodeToBuf(&dec, buf, &destLen, data, &srcLen,

        LZMA_FINISH_ANY, &status);

    if (res != SZ_OK || status == LZMA_STATUS_FINISHED_WITH_MARK ||

        status == LZMA_STATUS_NEEDS_MORE_INPUT) {

      goto exit;

    }

    size -= srcLen;

    data += srcLen;

  }

exit:

  Lzma2Dec_Free(&dec, &CommonAlloc);

  return 0;

}