* =====================================================================================
*/
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include "othello.h"
+#include "debug.h"
+
+unsigned int current_player(unsigned int round_count) {
+
+ if (round_count % 2 != 0) {
+ return player_two;
+ } else {
+ return player_one;
+ }
+}
+
+unsigned int current_opponent(unsigned int current_player) {
+
+ if (current_player == player_one) {
+ return player_two;
+ } else {
+ return player_one;
+ }
+}
+
+/* for consistency with ncurses, the board coordinates are in the following order:
+ * O--x-->
+ * |
+ * y
+ * |
+ * v
+ * The origin O has (1, 1) coordinates */
+
+unsigned int get_box_value(int y, int x, unsigned int pawn_array[board_size][board_size]) {
+
+ return pawn_array[y-1][x-1];
+}
+
+bool is_box_type(int y, int x, unsigned int pawn_array[board_size][board_size], unsigned int type) {
+
+ if (type > 2) {
+ return NULL;
+ }
+ if (get_box_value(y, x, pawn_array) == type) {
+ return true;
+ } else {
+ return false;
+ }
+}
+
+static bool is_valid_coordinates(int y, int x) {
+
+ if ((y > 0 && y < board_size + 1) && \
+ (x > 0 && x < board_size + 1)) {
+ return true;
+ } else {
+ return false;
+ }
+}
+
+/* helper function to set a correct value at the (y, x) coordinates in the pawns array */
+void set_pawn(int y, int x, unsigned int type, unsigned int pawn_array[board_size][board_size]) {
+
+ if (type > 0 && type < 3 && \
+ is_valid_coordinates(y, x)) {
+ pawn_array[y-1][x-1] = type;
+ }
+}
+
+/* reverse the pawn at (y, x) coordinates if it exists */
+static void reverse_pawn(int y, int x, unsigned int pawn_array[board_size][board_size]) {
+
+ if (is_box_type(y, x, pawn_array, black)) {
+ set_pawn(y, x, white, pawn_array);
+ } else if (is_box_type(y, x, pawn_array, white)) {
+ set_pawn(y, x, black, pawn_array);
+ }
+}
+
+void zero_pawns(unsigned int pawn_array[board_size][board_size]) {
+
+ for (int i = 1; i <= board_size; i++) {
+ for (int j = 1; j <= board_size; j++) {
+ set_pawn(i, j, empty, pawn_array);
+ }
+ }
+}
+
+/* set the pawns in the start position */
+void init_pawns(unsigned int pawn_array[board_size][board_size]) {
+
+ /* the 2D array zeroing is not necessary if it is properly initialized to zero */
+ zero_pawns(pawn_array);
+ set_pawn(5, 4, black, pawn_array);
+ set_pawn(4, 5, black, pawn_array);
+ set_pawn(4, 4, white, pawn_array);
+ set_pawn(5, 5, white, pawn_array);
+}
+
+unsigned int count_pawns_type(unsigned int pawn_array[board_size][board_size], unsigned int type) {
+ unsigned int count = 0;
+
+ if (type > 2) {
+ return 0;
+ }
+ for (int i = 1; i <= board_size; i++) {
+ for (int j = 1; j <= board_size; j++) {
+ if (is_box_type(i, j, pawn_array, type)) {
+ count++;
+ }
+ }
+ }
+ return count;
+}
+
+static void direction_to_coordinates(unsigned int direction, int* start_y, int* start_x) {
+
+ if (direction == north) {
+ *start_y = *start_y - 1;
+ } else if (direction == north_east) {
+ *start_y = *start_y - 1;
+ *start_x = *start_x + 1;
+ } else if (direction == east) {
+ *start_x = *start_x + 1;
+ } else if (direction == south_east) {
+ *start_y = *start_y + 1;
+ *start_x = *start_x + 1;
+ } else if (direction == south) {
+ *start_y = *start_y + 1;
+ } else if (direction == south_west) {
+ *start_y = *start_y + 1;
+ *start_x = *start_x - 1;
+ } else if (direction == west) {
+ *start_x = *start_x - 1;
+ } else if (direction == north_west) {
+ *start_y = *start_y - 1;
+ *start_x = *start_x - 1;
+ }
+}
+
+bool is_board_full(unsigned int pawn_array[board_size][board_size]) {
+
+ /* an alternate method is to test the round count vs. 60 */
+ for (int i = 1; i <= board_size; i++) {
+ for (int j = 1; j <= board_size; j++) {
+ if (is_box_type(i, j, pawn_array , empty)) {
+ return false;
+ }
+ }
+ }
+ return true;
+}
+
+unsigned int eval_winner(unsigned int nb_white, unsigned int nb_black) {
+
+ if (nb_white > nb_black) {
+ return player_two;
+ } else if (nb_white < nb_black) {
+ return player_one;
+ } else {
+ return 0;
+ }
+}
+
+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]) {
+ unsigned int nb_pawns_reversed = 0;
+ int moving_y = y, moving_x = x;
+
+ /* count the pawns to reverse in the chosen direction */
+ direction_to_coordinates(direction, &moving_y, &moving_x);
+ while (true) {
+ if (!is_valid_coordinates(moving_y, moving_x) || is_box_type(moving_y, moving_x, pawn_array, empty)) {
+ return 0;
+ }
+ if (is_box_type(moving_y, moving_x, pawn_array, current_player)) {
+ break;
+ }
+ nb_pawns_reversed++;
+ direction_to_coordinates(direction, &moving_y, &moving_x);
+ }
+ return nb_pawns_reversed;
+}
+
+/* revert the pawns if needed in one direction */
+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) {
+ unsigned int nb_pawns_reversed = 0;
+ int moving_y = y, moving_x = x;
+
+ nb_pawns_reversed = count_pawn_to_reverse_one_direction(moving_y, moving_x, direction, current_player, pawn_array);
+
+ /* now reverse the needed pawns */
+ if (nb_pawns_reversed > 0 && !dry_run) {
+ moving_y = y, moving_x = x;
+ direction_to_coordinates(direction, &moving_y, &moving_x);
+ while (!is_box_type(moving_y, moving_x, pawn_array, current_player)) {
+ reverse_pawn(moving_y, moving_x, pawn_array);
+ direction_to_coordinates(direction, &moving_y, &moving_x);
+ }
+ }
+ return nb_pawns_reversed;
+}
+
+/* loop optimized version of valid_shot changing nothing to the pawns 2D array */
+static bool is_legal_shot(int y, int x, unsigned int current_player, unsigned int pawn_array[board_size][board_size]) {
+ unsigned int nb_pawns_reversed = 0;
+
+ if (!is_valid_coordinates(y, x) || !is_box_type(y, x, pawn_array, empty)) {
+ return false;
+ }
+
+ for (unsigned int direction = north; direction <= north_west; direction++) {
+ nb_pawns_reversed += reverse_one_direction(y, x, direction, current_player, pawn_array, true);
+ if (nb_pawns_reversed > 0) {
+ return true;
+ }
+ }
+}
+
+/* play the shot if legal and flip or reverse the necessary pawns */
+unsigned int valid_shot(int y, int x, unsigned int current_player, unsigned int pawn_array[board_size][board_size]) {
+ unsigned int nb_pawns_reversed = 0;
+
+ if (!is_valid_coordinates(y, x) || !is_box_type(y, x, pawn_array, empty)) {
+ return 0;
+ }
+
+ for (unsigned int direction = north; direction <= north_west; direction++) {
+ nb_pawns_reversed += reverse_one_direction(y, x, direction, current_player, pawn_array, false);
+ }
+
+ if (nb_pawns_reversed == 0) {
+ return 0;
+ }
+
+ set_pawn(y, x, current_player, pawn_array);
+ return nb_pawns_reversed;
+}
repositories / Project_algorithmic_C.git / blobdiff