olivechess Code

#include <cassert>
#include <iomanip>
#include <sstream>
#include <stack>

#include "movegen.h"
#include "notation.h"
#include "position.h"

using namespace std;

static const char* PieceToChar[COLOR_NB] = { " PNBRQK", " pnbrqk" };


/// score_to_uci() converts a value to a string suitable for use with the UCI
/// protocol specifications:
///
/// cp <x>     The score from the engine's point of view in centipawns.
/// mate <y>   Mate in y moves, not plies. If the engine is getting mated
///            use negative values for y.

string score_to_uci(Value v, Value alpha, Value beta)
{

    stringstream ss;

    if (abs(v) < VALUE_MATE_IN_MAX_PLY)
        ss << "cp " << v * 100 / PawnValueEg;
    else
        ss << "mate " << (v > 0 ? VALUE_MATE - v + 1 : -VALUE_MATE - v) / 2;

    ss << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : "");

    return ss.str();
}


/// move_to_uci() converts a move to a string in coordinate notation
/// (g1f3, a7a8q, etc.). The only special case is castling moves, where we print
/// in the e1g1 notation in normal chess mode, and in e1h1 notation in chess960
/// mode. Internally castling moves are always encoded as "king captures rook".

const string move_to_uci(Move m, bool chess960)
{

    Square from = from_sq(m);
    Square to = to_sq(m);

    if (m == MOVE_NONE)
        return "(none)";

    if (m == MOVE_NULL)
        return "0000";

    if (type_of(m) == CASTLING && !chess960)
        to = make_square(to > from ? FILE_G : FILE_C, rank_of(from));

    string move = to_string(from) + to_string(to);

    if (type_of(m) == PROMOTION)
        move += PieceToChar[BLACK][promotion_type(m)]; // Lower case

    return move;
}


/// move_from_uci() takes a position and a string representing a move in
/// simple coordinate notation and returns an equivalent legal Move if any.

Move move_from_uci(const Position& pos, string& str)
{

    if (str.length() == 5) // Junior could send promotion piece in uppercase
        str[4] = char(tolower(str[4]));

    for (MoveList<LEGAL> it(pos); *it; ++it)
        if (str == move_to_uci(*it, pos.is_chess960()))
            return *it;

    return MOVE_NONE;
}


/// move_to_san() takes a position and a legal Move as input and returns its
/// short algebraic notation representation.

const string move_to_san(Position& pos, Move m)
{

    if (m == MOVE_NONE)
        return "(none)";

    if (m == MOVE_NULL)
        return "(null)";

    assert(MoveList<LEGAL>(pos).contains(m));

    Bitboard others, b;
    string san;
    Color us = pos.side_to_move();
    Square from = from_sq(m);
    Square to = to_sq(m);
    Piece pc = pos.piece_on(from);
    PieceType pt = type_of(pc);

    if (type_of(m) == CASTLING)
        san = to > from ? "O-O" : "O-O-O";
    else
    {
        if (pt != PAWN)
        {
            san = PieceToChar[WHITE][pt]; // Upper case

            // A disambiguation occurs if we have more then one piece of type 'pt'
            // that can reach 'to' with a legal move.
            others = b = (pos.attacks_from(pc, to) & pos.pieces(us, pt)) ^ from;

            while (b)
            {
                Square s = pop_lsb(&b);
                if (!pos.legal(make_move(s, to), pos.pinned_pieces(us)))
                    others ^= s;
            }

            if (!others)
            {
                /* Disambiguation is not needed */
            }

            else if (!(others & file_bb(from)))
                san += to_char(file_of(from));

            else if (!(others & rank_bb(from)))
                san += to_char(rank_of(from));

            else
                san += to_string(from);
        }
        else if (pos.capture(m))
            san = to_char(file_of(from));

        if (pos.capture(m))
            san += 'x';

        san += to_string(to);

        if (type_of(m) == PROMOTION)
            san += string("=") + PieceToChar[WHITE][promotion_type(m)];
    }

    if (pos.gives_check(m, CheckInfo(pos)))
    {
        StateInfo st;
        pos.do_move(m, st);
        san += MoveList<LEGAL>(pos).size() ? "+" : "#";
        pos.undo_move(m);
    }

    return san;
}


/// pretty_pv() formats human-readable search information, typically to be
/// appended to the search log file. It uses the two helpers below to pretty
/// format the time and score respectively.

static string format(int64_t msecs)
{

    const int MSecMinute = 1000 * 60;
    const int MSecHour   = 1000 * 60 * 60;

    int64_t hours   =   msecs / MSecHour;
    int64_t minutes =  (msecs % MSecHour) / MSecMinute;
    int64_t seconds = ((msecs % MSecHour) % MSecMinute) / 1000;

    stringstream ss;

    if (hours)
        ss << hours << ':';

    ss << setfill('0') << setw(2) << minutes << ':' << setw(2) << seconds;

    return ss.str();
}

static string format(Value v)
{

    stringstream ss;

    if (v >= VALUE_MATE_IN_MAX_PLY)
        ss << "#" << (VALUE_MATE - v + 1) / 2;

    else if (v <= VALUE_MATED_IN_MAX_PLY)
        ss << "-#" << (VALUE_MATE + v) / 2;

    else
        ss << setprecision(2) << fixed << showpos << double(v) / PawnValueEg;

    return ss.str();
}

string pretty_pv(Position& pos, int depth, Value value, int64_t msecs, Move pv[])
{

    const uint64_t K = 1000;
    const uint64_t M = 1000000;

    std::stack<StateInfo> st;
    Move* m = pv;
    string san, str, padding;
    stringstream ss;

    ss << setw(2) << depth << setw(8) << format(value) << setw(8) << format(msecs);

    if (pos.nodes_searched() < M)
        ss << setw(8) << pos.nodes_searched() / 1 << "  ";

    else if (pos.nodes_searched() < K * M)
        ss << setw(7) << pos.nodes_searched() / K << "K  ";

    else
        ss << setw(7) << pos.nodes_searched() / M << "M  ";

    str = ss.str();
    padding = string(str.length(), ' ');

    while (*m != MOVE_NONE)
    {
        san = move_to_san(pos, *m) + ' ';

        if ((str.length() + san.length()) % 80 <= san.length()) // Exceed 80 cols
            str += "\n" + padding;

        str += san;

        st.push(StateInfo());
        pos.do_move(*m++, st.top());
    }

    while (m != pv)
        pos.undo_move(*--m);

    return str;
}