| 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 | /** |
| 27 | * Get current round player integer |
| 28 | * @param round_count current round integer |
| 29 | * @return current round player |
| 30 | */ |
| 31 | unsigned int current_player(unsigned int round_count) { |
| 32 | |
| 33 | if (round_count % 2 != 0) { |
| 34 | return player_two; |
| 35 | } else { |
| 36 | return player_one; |
| 37 | } |
| 38 | } |
| 39 | |
| 40 | /** |
| 41 | * Get current round opponent integer |
| 42 | * @param current_player current round player |
| 43 | * @return current round opponent integer |
| 44 | */ |
| 45 | unsigned int current_opponent(unsigned int current_player) { |
| 46 | |
| 47 | if (current_player == player_one) { |
| 48 | return player_two; |
| 49 | } else { |
| 50 | return player_one; |
| 51 | } |
| 52 | } |
| 53 | |
| 54 | /* for consistency with ncurses, the board coordinates are in the following order: |
| 55 | * O--x--> |
| 56 | * | |
| 57 | * y |
| 58 | * | |
| 59 | * v |
| 60 | * The origin O has (1, 1) coordinates */ |
| 61 | |
| 62 | /** |
| 63 | * Get pawn value at coordinates (x,y) |
| 64 | * @param y y coordinate |
| 65 | * @param x x coordinate |
| 66 | * @param pawn_array array of played pawns |
| 67 | * @return pawn integer type |
| 68 | */ |
| 69 | unsigned int get_box_value(int y, int x, unsigned int pawn_array[board_size][board_size]) { |
| 70 | |
| 71 | return pawn_array[y-1][x-1]; |
| 72 | } |
| 73 | |
| 74 | bool is_box_type(int y, int x, unsigned int pawn_array[board_size][board_size], unsigned int type) { |
| 75 | |
| 76 | if (type > 2) { |
| 77 | return NULL; |
| 78 | } |
| 79 | if (get_box_value(y, x, pawn_array) == type) { |
| 80 | return true; |
| 81 | } else { |
| 82 | return false; |
| 83 | } |
| 84 | } |
| 85 | |
| 86 | static bool is_valid_coordinates(int y, int x) { |
| 87 | |
| 88 | if ((y > 0 && y < board_size + 1) && \ |
| 89 | (x > 0 && x < board_size + 1)) { |
| 90 | return true; |
| 91 | } else { |
| 92 | return false; |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | /* helper function to set a correct value at the (y, x) coordinates in the pawns array */ |
| 97 | void set_pawn(int y, int x, unsigned int type, unsigned int pawn_array[board_size][board_size]) { |
| 98 | |
| 99 | if (type > 0 && type < 3 && \ |
| 100 | is_valid_coordinates(y, x)) { |
| 101 | pawn_array[y-1][x-1] = type; |
| 102 | } //FIXME: else case should set invalid values to permit to catch errors |
| 103 | } |
| 104 | |
| 105 | /* reverse the pawn at (y, x) coordinates if it exists */ |
| 106 | static void reverse_pawn(int y, int x, unsigned int pawn_array[board_size][board_size]) { |
| 107 | |
| 108 | if (is_box_type(y, x, pawn_array, black)) { |
| 109 | set_pawn(y, x, white, pawn_array); |
| 110 | } else if (is_box_type(y, x, pawn_array, white)) { |
| 111 | set_pawn(y, x, black, pawn_array); |
| 112 | } |
| 113 | } |
| 114 | |
| 115 | void zero_pawns(unsigned int pawn_array[board_size][board_size]) { |
| 116 | |
| 117 | for (int i = 1; i <= board_size; i++) { |
| 118 | for (int j = 1; j <= board_size; j++) { |
| 119 | set_pawn(i, j, empty, pawn_array); |
| 120 | } |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | /* set the pawns in the start position */ |
| 125 | void init_pawns(unsigned int pawn_array[board_size][board_size]) { |
| 126 | |
| 127 | /* the 2D array zeroing is not necessary if it is properly initialized to zero */ |
| 128 | zero_pawns(pawn_array); |
| 129 | set_pawn(5, 4, black, pawn_array); |
| 130 | set_pawn(4, 5, black, pawn_array); |
| 131 | set_pawn(4, 4, white, pawn_array); |
| 132 | set_pawn(5, 5, white, pawn_array); |
| 133 | } |
| 134 | |
| 135 | unsigned int count_pawns_type(unsigned int pawn_array[board_size][board_size], unsigned int type) { |
| 136 | unsigned int count = 0; |
| 137 | |
| 138 | if (type > 2) { |
| 139 | return 0; |
| 140 | } |
| 141 | for (int i = 1; i <= board_size; i++) { |
| 142 | for (int j = 1; j <= board_size; j++) { |
| 143 | if (is_box_type(i, j, pawn_array, type)) { |
| 144 | count++; |
| 145 | } |
| 146 | } |
| 147 | } |
| 148 | return count; |
| 149 | } |
| 150 | |
| 151 | static void direction_to_coordinates(unsigned int direction, int* start_y, int* start_x) { |
| 152 | |
| 153 | if (direction == north) { |
| 154 | *start_y = *start_y - 1; |
| 155 | } else if (direction == north_east) { |
| 156 | *start_y = *start_y - 1; |
| 157 | *start_x = *start_x + 1; |
| 158 | } else if (direction == east) { |
| 159 | *start_x = *start_x + 1; |
| 160 | } else if (direction == south_east) { |
| 161 | *start_y = *start_y + 1; |
| 162 | *start_x = *start_x + 1; |
| 163 | } else if (direction == south) { |
| 164 | *start_y = *start_y + 1; |
| 165 | } else if (direction == south_west) { |
| 166 | *start_y = *start_y + 1; |
| 167 | *start_x = *start_x - 1; |
| 168 | } else if (direction == west) { |
| 169 | *start_x = *start_x - 1; |
| 170 | } else if (direction == north_west) { |
| 171 | *start_y = *start_y - 1; |
| 172 | *start_x = *start_x - 1; |
| 173 | } |
| 174 | } |
| 175 | |
| 176 | bool is_board_full(unsigned int pawn_array[board_size][board_size]) { |
| 177 | |
| 178 | /* an alternate method is to test the round count vs. 60 */ |
| 179 | for (int i = 1; i <= board_size; i++) { |
| 180 | for (int j = 1; j <= board_size; j++) { |
| 181 | if (is_box_type(i, j, pawn_array , empty)) { |
| 182 | return false; |
| 183 | } |
| 184 | } |
| 185 | } |
| 186 | return true; |
| 187 | } |
| 188 | |
| 189 | unsigned int eval_winner(unsigned int nb_white, unsigned int nb_black) { |
| 190 | |
| 191 | if (nb_white > nb_black) { |
| 192 | return player_two; |
| 193 | } else if (nb_white < nb_black) { |
| 194 | return player_one; |
| 195 | } else { |
| 196 | return 0; |
| 197 | } |
| 198 | } |
| 199 | |
| 200 | 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]) { |
| 201 | unsigned int nb_pawns_reversed = 0; |
| 202 | int moving_y = y, moving_x = x; |
| 203 | |
| 204 | /* count the pawns to reverse in the chosen direction */ |
| 205 | direction_to_coordinates(direction, &moving_y, &moving_x); |
| 206 | while (true) { |
| 207 | if (!is_valid_coordinates(moving_y, moving_x) || is_box_type(moving_y, moving_x, pawn_array, empty)) { |
| 208 | return 0; |
| 209 | } |
| 210 | if (is_box_type(moving_y, moving_x, pawn_array, current_player)) { |
| 211 | break; |
| 212 | } |
| 213 | nb_pawns_reversed++; |
| 214 | direction_to_coordinates(direction, &moving_y, &moving_x); |
| 215 | } |
| 216 | return nb_pawns_reversed; |
| 217 | } |
| 218 | |
| 219 | /* revert the pawns if needed in one direction */ |
| 220 | 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) { |
| 221 | unsigned int nb_pawns_reversed = 0; |
| 222 | int moving_y = y, moving_x = x; |
| 223 | |
| 224 | nb_pawns_reversed = count_pawn_to_reverse_one_direction(moving_y, moving_x, direction, current_player, pawn_array); |
| 225 | |
| 226 | /* now reverse the needed pawns */ |
| 227 | if (nb_pawns_reversed > 0 && !dry_run) { |
| 228 | moving_y = y, moving_x = x; |
| 229 | direction_to_coordinates(direction, &moving_y, &moving_x); |
| 230 | while (!is_box_type(moving_y, moving_x, pawn_array, current_player)) { |
| 231 | reverse_pawn(moving_y, moving_x, pawn_array); |
| 232 | direction_to_coordinates(direction, &moving_y, &moving_x); |
| 233 | } |
| 234 | } |
| 235 | return nb_pawns_reversed; |
| 236 | } |
| 237 | |
| 238 | /* loop optimized version of valid_shot function changing nothing to the pawns 2D array */ |
| 239 | bool is_legal_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 false; |
| 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, true); |
| 248 | if (nb_pawns_reversed > 0) { |
| 249 | return true; |
| 250 | } |
| 251 | } |
| 252 | return false; |
| 253 | } |
| 254 | |
| 255 | /* play the shot if legal and flip or reverse the necessary pawns */ |
| 256 | unsigned int valid_shot(int y, int x, unsigned int current_player, unsigned int pawn_array[board_size][board_size]) { |
| 257 | unsigned int nb_pawns_reversed = 0; |
| 258 | |
| 259 | if (!is_valid_coordinates(y, x) || !is_box_type(y, x, pawn_array, empty)) { |
| 260 | return 0; |
| 261 | } |
| 262 | |
| 263 | for (unsigned int direction = north; direction <= north_west; direction++) { |
| 264 | nb_pawns_reversed += reverse_one_direction(y, x, direction, current_player, pawn_array, false); |
| 265 | } |
| 266 | |
| 267 | if (nb_pawns_reversed == 0) { |
| 268 | return nb_pawns_reversed; |
| 269 | } |
| 270 | |
| 271 | set_pawn(y, x, current_player, pawn_array); |
| 272 | return nb_pawns_reversed; |
| 273 | } |
| 274 | |
| 275 | static void add_shots_list_cell(int y, int x, unsigned int type, struct shots_list_s* shots_list) { |
| 276 | struct shots_list_s* list_cell = (struct shots_list_s*)malloc(sizeof(struct shots_list_s)); |
| 277 | if (!list_cell) { |
| 278 | exit(EXIT_FAILURE); |
| 279 | } |
| 280 | |
| 281 | if (type > 0 && type < 5 && is_valid_coordinates(y, x)) { |
| 282 | list_cell->y = y; |
| 283 | list_cell->x = x; |
| 284 | list_cell->type = type; |
| 285 | list_add_tail(&(list_cell->list), &(shots_list->list)); |
| 286 | } |
| 287 | } |
| 288 | |
| 289 | void free_shots_list(struct shots_list_s* shots_list) { |
| 290 | struct shots_list_s* list_counter; |
| 291 | |
| 292 | while (!list_empty(&shots_list->list)) { |
| 293 | list_counter = list_entry(shots_list->list.next, struct shots_list_s, list); |
| 294 | list_del(&(list_counter->list)); |
| 295 | free(list_counter); |
| 296 | } |
| 297 | |
| 298 | } |
| 299 | |
| 300 | void build_playable_shots_list(unsigned int current_player, struct shots_list_s* shots_list, unsigned int pawn_array[board_size][board_size]) { |
| 301 | |
| 302 | for (unsigned int i = 0; i <= board_size; i++) { |
| 303 | for (unsigned int j = 0; j <= board_size; j++) { |
| 304 | if (is_legal_shot(i, j, current_player, pawn_array)) { |
| 305 | add_shots_list_cell(i, j, hint_allowed, shots_list); |
| 306 | /* FIXME: a neighbourhood detection is needed |
| 307 | } else if (is_box_type(i, j, pawn_array, empty)){ |
| 308 | add_shots_list_cell(i, j, hint_forbidden, shots_list); |
| 309 | */ |
| 310 | } |
| 311 | } |
| 312 | } |
| 313 | } |