// 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_STONE_H_

#define CC_STONE_H_

#include <cstdint>

#include "cc/check.h"

#include "cc/color.h"

#include "cc/group.h"

namespace minigo {

// Stone represents either a stone on the board or, when empty() == true, an

// empty point on the board.

// Stone tracks both the color (empty, black or white) and group the ID of the

// stone's.

class Stone {

public:

Stone() = default;

Stone(const Stone& other) = default;

Stone(Color color, GroupId group_id)

: value_(static_cast<uint16_t>(color) | (group_id << 2)) {

MG_DCHECK(color != Color::kEmpty);

}

Stone& operator=(const Stone& other) = default;

bool empty() const { return value_ == 0; }

Color color() const { return static_cast<Color>(value_ & 3); }

GroupId group_id() const { return value_ >> 2; }

private:

uint16_t value_ = 0;

};

} // namespace minigo

#endif // CC_STONE_H_