| 1 | /* |
| 2 | * ===================================================================================== |
| 3 | * |
| 4 | * Filename: othello.c |
| 5 | * |
| 6 | * Description: Handle the othello board content |
| 7 | * |
| 8 | * Version: 1.0 |
| 9 | * Created: 25/04/2017 15:16:08 |
| 10 | * Revision: none |
| 11 | * Compiler: gcc |
| 12 | * |
| 13 | * Author: Jerome Benoit (fraggle), jerome.benoit@piment-noir.org |
| 14 | * Organization: Piment Noir |
| 15 | * |
| 16 | * ===================================================================================== |
| 17 | */ |
| 18 | |
| 19 | #include <stdlib.h> |
| 20 | #include <stdbool.h> |
| 21 | #include <string.h> |
| 22 | |
| 23 | #include "othello.h" |
| 24 | #include "debug.h" |
| 25 | |
| 26 | unsigned int current_player(unsigned int round_count) { |
| 27 | |
| 28 | if (round_count % 2 != 0) { |
| 29 | return player_two; |
| 30 | } else { |
| 31 | return player_one; |
| 32 | } |
| 33 | } |
| 34 | |
| 35 | unsigned int current_opponent(unsigned int current_player) { |
| 36 | |
| 37 | if (current_player == player_one) { |
| 38 | return player_two; |
| 39 | } else { |
| 40 | return player_one; |
| 41 | } |
| 42 | } |
| 43 | |
| 44 | /* for consistency with ncurses, the board coordinates are in the following order: |
| 45 | * O--x--> |
| 46 | * | |
| 47 | * y |
| 48 | * | |
| 49 | * v |
| 50 | * The origin O has (1, 1) coordinates */ |
| 51 | |
| 52 | unsigned int get_box_value(int y, int x, unsigned int pawn_array[board_size][board_size]) { |
| 53 | |
| 54 | return pawn_array[y-1][x-1]; |
| 55 | } |
| 56 | |
| 57 | bool is_box_type(int y, int x, unsigned int pawn_array[board_size][board_size], unsigned int type) { |
| 58 | |
| 59 | if (type > 2) { |
| 60 | return NULL; |
| 61 | } |
| 62 | if (get_box_value(y, x, pawn_array) == type) { |
| 63 | return true; |
| 64 | } else { |
| 65 | return false; |
| 66 | } |
| 67 | } |
| 68 | |
| 69 | static bool is_valid_coordinates(int y, int x) { |
| 70 | |
| 71 | if ((y > 0 && y < board_size + 1) && \ |
| 72 | (x > 0 && x < board_size + 1)) { |
| 73 | return true; |
| 74 | } else { |
| 75 | return false; |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | /* helper function to set a correct value at the (y, x) coordinates in the pawns array */ |
| 80 | void set_pawn(int y, int x, unsigned int type, unsigned int pawn_array[board_size][board_size]) { |
| 81 | |
| 82 | if (type > 0 && type < 3 && \ |
| 83 | is_valid_coordinates(y, x)) { |
| 84 | pawn_array[y-1][x-1] = type; |
| 85 | } //FIXME: else case should set invalid values to permit to catch errors |
| 86 | } |
| 87 | |
| 88 | /* reverse the pawn at (y, x) coordinates if it exists */ |
| 89 | static void reverse_pawn(int y, int x, unsigned int pawn_array[board_size][board_size]) { |
| 90 | |
| 91 | if (is_box_type(y, x, pawn_array, black)) { |
| 92 | set_pawn(y, x, white, pawn_array); |
| 93 | } else if (is_box_type(y, x, pawn_array, white)) { |
| 94 | set_pawn(y, x, black, pawn_array); |
| 95 | } |
| 96 | } |
| 97 | |
| 98 | void zero_pawns(unsigned int pawn_array[board_size][board_size]) { |
| 99 | |
| 100 | for (int i = 1; i <= board_size; i++) { |
| 101 | for (int j = 1; j <= board_size; j++) { |
| 102 | set_pawn(i, j, empty, pawn_array); |
| 103 | } |
| 104 | } |
| 105 | } |
| 106 | |
| 107 | /* set the pawns in the start position */ |
| 108 | void init_pawns(unsigned int pawn_array[board_size][board_size]) { |
| 109 | |
| 110 | /* the 2D array zeroing is not necessary if it is properly initialized to zero */ |
| 111 | zero_pawns(pawn_array); |
| 112 | set_pawn(5, 4, black, pawn_array); |
| 113 | set_pawn(4, 5, black, pawn_array); |
| 114 | set_pawn(4, 4, white, pawn_array); |
| 115 | set_pawn(5, 5, white, pawn_array); |
| 116 | } |
| 117 | |
| 118 | unsigned int count_pawns_type(unsigned int pawn_array[board_size][board_size], unsigned int type) { |
| 119 | unsigned int count = 0; |
| 120 | |
| 121 | if (type > 2) { |
| 122 | return 0; |
| 123 | } |
| 124 | for (int i = 1; i <= board_size; i++) { |
| 125 | for (int j = 1; j <= board_size; j++) { |
| 126 | if (is_box_type(i, j, pawn_array, type)) { |
| 127 | count++; |
| 128 | } |
| 129 | } |
| 130 | } |
| 131 | return count; |
| 132 | } |
| 133 | |
| 134 | static void direction_to_coordinates(unsigned int direction, int* start_y, int* start_x) { |
| 135 | |
| 136 | if (direction == north) { |
| 137 | *start_y = *start_y - 1; |
| 138 | } else if (direction == north_east) { |
| 139 | *start_y = *start_y - 1; |
| 140 | *start_x = *start_x + 1; |
| 141 | } else if (direction == east) { |
| 142 | *start_x = *start_x + 1; |
| 143 | } else if (direction == south_east) { |
| 144 | *start_y = *start_y + 1; |
| 145 | *start_x = *start_x + 1; |
| 146 | } else if (direction == south) { |
| 147 | *start_y = *start_y + 1; |
| 148 | } else if (direction == south_west) { |
| 149 | *start_y = *start_y + 1; |
| 150 | *start_x = *start_x - 1; |
| 151 | } else if (direction == west) { |
| 152 | *start_x = *start_x - 1; |
| 153 | } else if (direction == north_west) { |
| 154 | *start_y = *start_y - 1; |
| 155 | *start_x = *start_x - 1; |
| 156 | } |
| 157 | } |
| 158 | |
| 159 | bool is_board_full(unsigned int pawn_array[board_size][board_size]) { |
| 160 | |
| 161 | /* an alternate method is to test the round count vs. 60 */ |
| 162 | for (int i = 1; i <= board_size; i++) { |
| 163 | for (int j = 1; j <= board_size; j++) { |
| 164 | if (is_box_type(i, j, pawn_array , empty)) { |
| 165 | return false; |
| 166 | } |
| 167 | } |
| 168 | } |
| 169 | return true; |
| 170 | } |
| 171 | |
| 172 | unsigned int eval_winner(unsigned int nb_white, unsigned int nb_black) { |
| 173 | |
| 174 | if (nb_white > nb_black) { |
| 175 | return player_two; |
| 176 | } else if (nb_white < nb_black) { |
| 177 | return player_one; |
| 178 | } else { |
| 179 | return 0; |
| 180 | } |
| 181 | } |
| 182 | |
| 183 | static unsigned int count_pawn_to_reverse_one_direction(int y, int x, int direction, unsigned int current_player, unsigned int pawn_array[board_size][board_size]) { |
| 184 | unsigned int nb_pawns_reversed = 0; |
| 185 | int moving_y = y, moving_x = x; |
| 186 | |
| 187 | /* count the pawns to reverse in the chosen direction */ |
| 188 | direction_to_coordinates(direction, &moving_y, &moving_x); |
| 189 | while (true) { |
| 190 | if (!is_valid_coordinates(moving_y, moving_x) || is_box_type(moving_y, moving_x, pawn_array, empty)) { |
| 191 | return 0; |
| 192 | } |
| 193 | if (is_box_type(moving_y, moving_x, pawn_array, current_player)) { |
| 194 | break; |
| 195 | } |
| 196 | nb_pawns_reversed++; |
| 197 | direction_to_coordinates(direction, &moving_y, &moving_x); |
| 198 | } |
| 199 | return nb_pawns_reversed; |
| 200 | } |
| 201 | |
| 202 | /* revert the pawns if needed in one direction */ |
| 203 | static unsigned int reverse_one_direction(int y, int x, int direction, unsigned int current_player, unsigned int pawn_array[board_size][board_size], bool dry_run) { |
| 204 | unsigned int nb_pawns_reversed = 0; |
| 205 | int moving_y = y, moving_x = x; |
| 206 | |
| 207 | nb_pawns_reversed = count_pawn_to_reverse_one_direction(moving_y, moving_x, direction, current_player, pawn_array); |
| 208 | |
| 209 | /* now reverse the needed pawns */ |
| 210 | if (nb_pawns_reversed > 0 && !dry_run) { |
| 211 | moving_y = y, moving_x = x; |
| 212 | direction_to_coordinates(direction, &moving_y, &moving_x); |
| 213 | while (!is_box_type(moving_y, moving_x, pawn_array, current_player)) { |
| 214 | reverse_pawn(moving_y, moving_x, pawn_array); |
| 215 | direction_to_coordinates(direction, &moving_y, &moving_x); |
| 216 | } |
| 217 | } |
| 218 | return nb_pawns_reversed; |
| 219 | } |
| 220 | |
| 221 | /* loop optimized version of valid_shot changing nothing to the pawns 2D array */ |
| 222 | static bool is_legal_shot(int y, int x, unsigned int current_player, unsigned int pawn_array[board_size][board_size]) { |
| 223 | unsigned int nb_pawns_reversed = 0; |
| 224 | |
| 225 | if (!is_valid_coordinates(y, x) || !is_box_type(y, x, pawn_array, empty)) { |
| 226 | return false; |
| 227 | } |
| 228 | |
| 229 | for (unsigned int direction = north; direction <= north_west; direction++) { |
| 230 | nb_pawns_reversed += reverse_one_direction(y, x, direction, current_player, pawn_array, true); |
| 231 | if (nb_pawns_reversed > 0) { |
| 232 | return true; |
| 233 | } |
| 234 | } |
| 235 | return false; |
| 236 | } |
| 237 | |
| 238 | /* play the shot if legal and flip or reverse the necessary pawns */ |
| 239 | unsigned int valid_shot(int y, int x, unsigned int current_player, unsigned int pawn_array[board_size][board_size]) { |
| 240 | unsigned int nb_pawns_reversed = 0; |
| 241 | |
| 242 | if (!is_valid_coordinates(y, x) || !is_box_type(y, x, pawn_array, empty)) { |
| 243 | return 0; |
| 244 | } |
| 245 | |
| 246 | for (unsigned int direction = north; direction <= north_west; direction++) { |
| 247 | nb_pawns_reversed += reverse_one_direction(y, x, direction, current_player, pawn_array, false); |
| 248 | } |
| 249 | |
| 250 | if (nb_pawns_reversed == 0) { |
| 251 | return nb_pawns_reversed; |
| 252 | } |
| 253 | |
| 254 | set_pawn(y, x, current_player, pawn_array); |
| 255 | return nb_pawns_reversed; |
| 256 | } |
| 257 | |
| 258 | static void add_shots_list_cell(int y, int x, unsigned int type, struct shots_list_s* shots_list) { |
| 259 | struct shots_list_s* list_cell = malloc(sizeof(struct shots_list_s)); |
| 260 | if (!list_cell) { |
| 261 | exit(EXIT_FAILURE); |
| 262 | } |
| 263 | |
| 264 | if (type > 0 && type < 5 && is_valid_coordinates(y, x)) { |
| 265 | list_cell->y = y; |
| 266 | list_cell->x = x; |
| 267 | list_cell->type = type; |
| 268 | list_add_tail(&(list_cell->list), &(shots_list->list)); |
| 269 | } |
| 270 | } |
| 271 | |
| 272 | void free_shots_list(struct shots_list_s* shots_list) { |
| 273 | struct shots_list_s* list_counter; |
| 274 | |
| 275 | while (!list_empty(&shots_list->list)) { |
| 276 | list_counter = list_entry(shots_list->list.next, struct shots_list_s, list); |
| 277 | list_del(&list_counter->list); |
| 278 | free(list_counter); |
| 279 | } |
| 280 | |
| 281 | } |
| 282 | |
| 283 | void build_playable_shots_list(unsigned int current_player, struct shots_list_s* shots_list, unsigned int pawn_array[board_size][board_size]) { |
| 284 | |
| 285 | for (unsigned int i = 0; i <= board_size; i++) { |
| 286 | for (unsigned int j = 0; j <= board_size; j++) { |
| 287 | if (is_legal_shot(i, j, current_player, pawn_array)) { |
| 288 | add_shots_list_cell(i, j, hint_allowed, shots_list); |
| 289 | /* FIXME: a neighbourhood detection is needed |
| 290 | } else if (is_box_type(i, j, pawn_array, empty)){ |
| 291 | add_shots_list_cell(i, j, hint_forbidden, shots_list); |
| 292 | */ |
| 293 | } |
| 294 | } |
| 295 | } |
| 296 | } |