/*

Stockfish, a UCI chess playing engine derived from Glaurung 2.1

Copyright (C) 2004-2008 Tord Romstad (Glaurung author)

Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad

Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad

Stockfish 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.

Stockfish 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 <http://www.gnu.org/licenses/>.

*/

#ifndef THREAD_H_INCLUDED

#define THREAD_H_INCLUDED

#include <atomic>

#include <condition_variable>

#include <mutex>

#include <thread>

#include <vector>

#include "material.h"

#include "movepick.h"

#include "pawns.h"

#include "position.h"

#include "search.h"

#include "thread_win32.h"

/// Thread class keeps together all the thread-related stuff. We use

/// per-thread pawn and material hash tables so that once we get a

/// pointer to an entry its life time is unlimited and we don't have

/// to care about someone changing the entry under our feet.

class Thread {

Mutex mutex;

ConditionVariable cv;

size_t idx;

bool exit = false, searching = true; // Set before starting std::thread

std::thread stdThread;

public:

explicit Thread(size_t);

virtual ~Thread();

virtual void search();

void clear();

void idle_loop();

void start_searching();

void wait_for_search_finished();

Pawns::Table pawnsTable;

Material::Table materialTable;

Endgames endgames;

size_t pvIdx, pvLast;

int selDepth, nmpMinPly;

Color nmpColor;

std::atomic<uint64_t> nodes, tbHits;

Position rootPos;

Search::RootMoves rootMoves;

Depth rootDepth, completedDepth;

CounterMoveHistory counterMoves;

ButterflyHistory mainHistory;

CapturePieceToHistory captureHistory;

ContinuationHistory continuationHistory;

Score contempt;

};

/// MainThread is a derived class specific for main thread

struct MainThread : public Thread {

using Thread::Thread;

void search() override;

void check_time();

double bestMoveChanges, previousTimeReduction;

Value previousScore;

int callsCnt;

};

/// ThreadPool struct handles all the threads-related stuff like init, starting,

/// parking and, most importantly, launching a thread. All the access to threads

/// is done through this class.

struct ThreadPool : public std::vector<Thread*> {

void start_thinking(Position&, StateListPtr&, const Search::LimitsType&, bool = false);

void clear();

void set(size_t);

MainThread* main() const { return static_cast<MainThread*>(front()); }

uint64_t nodes_searched() const { return accumulate(&Thread::nodes); }

uint64_t tb_hits() const { return accumulate(&Thread::tbHits); }

std::atomic_bool stop, ponder, stopOnPonderhit;

private:

StateListPtr setupStates;

uint64_t accumulate(std::atomic<uint64_t> Thread::* member) const {

uint64_t sum = 0;

for (Thread* th : *this)

sum += (th->*member).load(std::memory_order_relaxed);

return sum;

}

};

extern ThreadPool Threads;

#endif // #ifndef THREAD_H_INCLUDED