1 /* ttt.c - client-server tic-tac-toe game
3 * Copyright © 2005 Carl Worth
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2, or (at your option)
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software Foundation,
17 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 * Author: Carl Worth <cworth@cworth.org>
23 #include "ttt-board.h"
24 #include "ttt-error.h"
26 /* Initialize an empty board. */
28 ttt_board_init (ttt_board_t *board)
31 for (i = 0; i < TTT_BOARD_MAX_CELLS; i++)
33 board->cells[i] = TTT_CELL_EMPTY;
35 board->current_player = TTT_CELL_X;
38 /* Initialize a board from its string representation.
40 * Returns: TTT_BOARD_SUCCESS or TTT_BOARD_INVALID_BOARD if the board
41 * string could not be properly parsed.
44 ttt_board_init_from_string (ttt_board_t *board,
50 /* Return the string representation of a board.
52 * The return value is a malloc()ed string that should be free()ed
53 * when no longer needed.
55 * Errors: If out-of-memory occurs, this function will not return.
58 ttt_board_to_string (ttt_board_t *board)
65 board->cells[0], board->cells[1], board->cells[2],
66 board->cells[3], board->cells[4], board->cells[5],
67 board->cells[6], board->cells[7], board->cells[8]);
71 /* Write a string representation of a board to the provided file.
73 * Errors: If out-of-memory or a file IO error occurs, this function
77 ttt_board_write (ttt_board_t *board, FILE *file)
81 s = ttt_board_to_string (board);
83 xfwrite (s, 1, strlen (s) + 1, file);
88 /* Makes a new move in the given board.
90 * The move value is a number from 0 to 9 giving the position to be
97 * Returns: TTT_ERROR_NONE if a move is made succesfully. TTT_ERROR_NOT_VALID_MOVE
98 * if a move is invalid (the given cell is not empty).
101 ttt_error_t ttt_board_make_move (ttt_board_t *board, int move)
103 if (board->cells[move] != TTT_CELL_EMPTY)
104 return TTT_ERROR_NOT_VALID_MOVE;
106 board->cells[move] = board->current_player;
108 if (board->current_player == TTT_CELL_X)
109 board->current_player = TTT_CELL_O;
111 board->current_player = TTT_CELL_X;
112 return TTT_ERROR_NONE;
115 /* Checks to see if a player has won the game and should be called
118 * Returns: TTT_CELL_X if X's win. TTT_CELL_O if O's
119 * win. TTT_CELL_EMPTY if no win. The game can then check the value
120 * of the return and declare the winner.
123 ttt_cell_t ttt_board_is_won (ttt_board_t *board)
127 /* Loop over rows and columns looking for a win. */
128 for (i = 0; i < 3; i++)
130 /* Check the current column */
131 if (board->cells[i] != TTT_CELL_EMPTY &&
132 board->cells[i] == board->cells[i + 3] &&
133 board->cells[i] == board->cells[i + 6])
135 return board->cells[i];
138 /* Check the current row */
139 if (board->cells[i * 3] != TTT_CELL_EMPTY &&
140 board->cells[i * 3] == board->cells[(i * 3) + 1] &&
141 board->cells[i * 3] == board->cells[(i * 3) + 2])
143 return board->cells[i * 3];
147 if (board->cells[0] != TTT_CELL_EMPTY &&
148 board->cells[0] == board->cells[4] &&
149 board->cells[0]== board->cells[8])
151 return board->cells[0];
154 if (board->cells[2] != TTT_CELL_EMPTY &&
155 board->cells[2] == board->cells[4] &&
156 board->cells[2]== board->cells[6])
158 return board->cells[2];
161 return TTT_CELL_EMPTY;