text: /*
    Stockfish, a UCI chess playing engine derived from Glaurung 2.1
    Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
    Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, 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/>.
  */
  
  
  #if !defined(SQUARE_H_INCLUDED)
  #define SQUARE_H_INCLUDED
  
  ////
  //// Includes
  ////
  
  #include <cstdlib> // for abs()
  #include <string>
  
  #include "color.h"
  #include "misc.h"
  
  
  ////
  //// Types
  ////
  
  enum Square {
    SQ_A1, SQ_B1, SQ_C1, SQ_D1, SQ_E1, SQ_F1, SQ_G1, SQ_H1,
    SQ_A2, SQ_B2, SQ_C2, SQ_D2, SQ_E2, SQ_F2, SQ_G2, SQ_H2,
    SQ_A3, SQ_B3, SQ_C3, SQ_D3, SQ_E3, SQ_F3, SQ_G3, SQ_H3,
    SQ_A4, SQ_B4, SQ_C4, SQ_D4, SQ_E4, SQ_F4, SQ_G4, SQ_H4,
    SQ_A5, SQ_B5, SQ_C5, SQ_D5, SQ_E5, SQ_F5, SQ_G5, SQ_H5,
    SQ_A6, SQ_B6, SQ_C6, SQ_D6, SQ_E6, SQ_F6, SQ_G6, SQ_H6,
    SQ_A7, SQ_B7, SQ_C7, SQ_D7, SQ_E7, SQ_F7, SQ_G7, SQ_H7,
    SQ_A8, SQ_B8, SQ_C8, SQ_D8, SQ_E8, SQ_F8, SQ_G8, SQ_H8,
    SQ_NONE
  };
  
  enum File {
    FILE_A, FILE_B, FILE_C, FILE_D, FILE_E, FILE_F, FILE_G, FILE_H, FILE_NONE
  };
  
  enum Rank {
    RANK_1, RANK_2, RANK_3, RANK_4, RANK_5, RANK_6, RANK_7, RANK_8, RANK_NONE
  };
  
  enum SquareDelta {
    DELTA_SSW = -021, DELTA_SS = -020, DELTA_SSE = -017, DELTA_SWW = -012,
    DELTA_SW = -011, DELTA_S = -010, DELTA_SE = -07, DELTA_SEE = -06,
    DELTA_W = -01, DELTA_ZERO = 0, DELTA_E = 01, DELTA_NWW = 06, DELTA_NW = 07,
    DELTA_N = 010, DELTA_NE = 011, DELTA_NEE = 012, DELTA_NNW = 017,
    DELTA_NN = 020, DELTA_NNE = 021
  };
  
  
  ////
  //// Constants
  ////
  
  const int FlipMask = 070;
  const int FlopMask = 07;
  
  
  ////
  //// Inline functions
  ////
  
  inline File operator+ (File x, int i) { return File(int(x) + i); }
  inline File operator+ (File x, File y) { return x + int(y); }
  inline void operator++ (File &x, int) { x = File(int(x) + 1); }
  inline void operator+= (File &x, int i) { x = File(int(x) + i); }
  inline File operator- (File x, int i) { return File(int(x) - i); }
  inline void operator-- (File &x, int) { x = File(int(x) - 1); }
  inline void operator-= (File &x, int i) { x = File(int(x) - i); }
  
  inline Rank operator+ (Rank x, int i) { return Rank(int(x) + i); }
  inline Rank operator+ (Rank x, Rank y) { return x + int(y); }
  inline void operator++ (Rank &x, int) { x = Rank(int(x) + 1); }
  inline void operator+= (Rank &x, int i) { x = Rank(int(x) + i); }
  inline Rank operator- (Rank x, int i) { return Rank(int(x) - i); }
  inline void operator-- (Rank &x, int) { x = Rank(int(x) - 1); }
  inline void operator-= (Rank &x, int i) { x = Rank(int(x) - i); }
  
  inline Square operator+ (Square x, int i) { return Square(int(x) + i); }
  inline void operator++ (Square &x, int) { x = Square(int(x) + 1); }
  inline void operator+= (Square &x, int i) { x = Square(int(x) + i); }
  inline Square operator- (Square x, int i) { return Square(int(x) - i); }
  inline void operator-- (Square &x, int) { x = Square(int(x) - 1); }
  inline void operator-= (Square &x, int i) { x = Square(int(x) - i); }
  inline Square operator+ (Square x, SquareDelta i) { return Square(int(x) + i); }
  inline void operator+= (Square &x, SquareDelta i) { x = Square(int(x) + i); }
  inline Square operator- (Square x, SquareDelta i) { return Square(int(x) - i); }
  inline void operator-= (Square &x, SquareDelta i) { x = Square(int(x) - i); }
  inline SquareDelta operator- (Square x, Square y) {
    return SquareDelta(int(x) - int(y));
  }
  
  inline Square make_square(File f, Rank r) {
    return Square(int(f) | (int(r) << 3));
  }
  
  inline File square_file(Square s) {
    return File(int(s) & 7);
  }
  
  inline Rank square_rank(Square s) {
    return Rank(int(s) >> 3);
  }
  
  inline Square flip_square(Square s) {
    return Square(int(s) ^ FlipMask);
  }
  
  inline Square flop_square(Square s) {
    return Square(int(s) ^ FlopMask);
  }
  
  inline Square relative_square(Color c, Square s) {
    return Square(int(s) ^ (int(c) * FlipMask));
  }
  
  inline Rank relative_rank(Color c, Square s) {
    return square_rank(relative_square(c, s));
  }
  
  inline Color square_color(Square s) {
    return Color((int(square_file(s)) + int(square_rank(s))) & 1);
  }
  
  inline int file_distance(File f1, File f2) {
    return abs(int(f1) - int(f2));
  }
  
  inline int file_distance(Square s1, Square s2) {
    return file_distance(square_file(s1), square_file(s2));
  }
  
  inline int rank_distance(Rank r1, Rank r2) {
    return abs(int(r1) - int(r2));
  }
  
  inline int rank_distance(Square s1, Square s2) {
    return rank_distance(square_rank(s1), square_rank(s2));
  }
  
  inline int square_distance(Square s1, Square s2) {
    return Max(file_distance(s1, s2), rank_distance(s1, s2));
  }
  
  inline File file_from_char(char c) {
    return File(c - 'a') + FILE_A;
  }
  
  inline char file_to_char(File f) {
    return char(f - FILE_A + int('a'));
  }
  
  inline Rank rank_from_char(char c) {
    return Rank(c - '1') + RANK_1;
  }
  
  inline char rank_to_char(Rank r) {
    return char(r - RANK_1 + int('1'));
  }
  
  inline Square square_from_string(const std::string& str) {
    return make_square(file_from_char(str[0]), rank_from_char(str[1]));
  }
  
  inline const std::string square_to_string(Square s) {
    std::string str;
    str += file_to_char(square_file(s));
    str += rank_to_char(square_rank(s));
    return str;
  }
  
  inline bool file_is_ok(File f) {
    return f >= FILE_A && f <= FILE_H;
  }
  
  inline bool rank_is_ok(Rank r) {
    return r >= RANK_1 && r <= RANK_8;
  }
  
  inline bool square_is_ok(Square s) {
    return file_is_ok(square_file(s)) && rank_is_ok(square_rank(s));
  }
  
  #endif // !defined(SQUARE_H_INCLUDED)
  