/*

  This file is part of solidity.

  solidity 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.

  solidity 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 solidity.  If not, see <http://www.gnu.org/licenses/>.

*/

// SPDX-License-Identifier: GPL-3.0

#include <test/tools/ossfuzz/SolidityCustomMutatorInterface.h>

#include <test/tools/ossfuzz/SolidityGenerator.h>

#include <liblangutil/Exceptions.h>

using namespace solidity::test::fuzzer::mutator;

// Prototype as we can't use the FuzzerInterface.h header.

extern "C" size_t LLVMFuzzerMutate(uint8_t* _data, size_t _size, size_t _maxSize);

extern "C" size_t LLVMFuzzerCustomMutator(uint8_t* _data, size_t size, size_t _maxSize, unsigned int seed);

namespace

{

/// Define Solidity's custom mutator by implementing libFuzzer's

/// custom mutator external interface.

extern "C" size_t LLVMFuzzerCustomMutator(

  uint8_t* _data,

  size_t _size,

  size_t _maxSize,

  unsigned int _seed

)

{

  solAssert(_data, "libFuzzerInterface: libFuzzer supplied bad buffer");

  if (_maxSize <= _size || _size == 0)

    return LLVMFuzzerMutate(_data, _size, _maxSize);

  return SolidityCustomMutatorInterface{_data, _size, _maxSize, _seed}.generate();

}

}

SolidityCustomMutatorInterface::SolidityCustomMutatorInterface(

  uint8_t* _data,

  size_t _size,

  size_t _maxSize,

  unsigned int _seed

  ):

  data(_data),

  size(_size),

  maxMutantSize(_maxSize),

  generator(std::make_shared<SolidityGenerator>(_seed))

{}

size_t SolidityCustomMutatorInterface::generate()

{

  std::string testCase = generator->generateTestProgram();

  solAssert(

    !testCase.empty() && data,

    "Solc custom mutator: Invalid mutant or memory pointer"

  );

  size_t mutantSize = std::min(testCase.size(), maxMutantSize - 1);

  mempcpy(data, testCase.data(), mutantSize);

  return mutantSize;

}