// Copyright 2018 Google LLC

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

// http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#ifndef CC_ZOBRIST_H_

#define CC_ZOBRIST_H_

#include <algorithm>

#include <array>

#include <cstdint>

#include "cc/color.h"

#include "cc/constants.h"

#include "cc/coord.h"

namespace minigo {

namespace zobrist {

using Hash = uint64_t;

namespace internal {

extern Hash kBlackToPlayHash;

extern Hash kOpponentPassedHash;

extern std::array<std::array<Hash, 3>, kNumMoves> kMoveHashes;

extern std::array<Hash, kN * kN> kIllegalEmptyPointHashes;

} // namespace internal

// Non-zero when it's black's turn.

inline Hash ToPlayHash(Color color) {

return color == Color::kBlack ? internal::kBlackToPlayHash : 0;

}

// Hash set when the previous move was a pass.

inline Hash OpponentPassedHash() { return internal::kOpponentPassedHash; }

// Hashes for moves by black and white.

inline Hash MoveHash(Coord c, Color color) {

return internal::kMoveHashes[c][static_cast<int>(color)];

}

// Hashes used for empty points that can't be played because of things like

// self-capture, ko or positional superko.

inline Hash IllegalEmptyPointHash(Coord c) {

return internal::kIllegalEmptyPointHashes[c];

}

void Init(uint64_t seed);

} // namespace zobrist

} // namespace minigo

#endif // CC_ZOBRIST_H_