+/*
+ * Copyright (C) 2008 Carl Worth
+ *
+ * This program 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.
+ *
+ * This program 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/ .
+ *
+ * Author: Carl Worth <cworth@cworth.org>
+ */
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include <glib.h>
+
+#include "loa-board.h"
+
+/* Given an (x,y) position on the board, return the index of the array
+ * used to count pieces in diagonal rows running from upper-left to
+ * lower-right, (like a grave accent: à or like a backslash: \).
+ *
+ * This is the array to look into when a move occurs with dx and dy of
+ * the same sign. */
+static int
+_grave_index (int x, int y)
+{
+ return x - y + LOA_BOARD_SIZE - 1;
+}
+
+/* Given an (x,y) position on the board, return the index of the array
+ * used to count pieces in diagonal rows running from lower-left to
+ * upper-right, (like an acute accent: á or like a forward slash: /).
+ *
+ * This is the array to look into when a move occurs with dx and dy of
+ * opposite sign, (one positive, one negative). */
+static int
+_acute_index (int x, int y)
+{
+ return x + y;
+}
+
+static void
+loa_board_add_piece (loa_board_t *board, int x, int y, loa_cell_t cell)
+{
+ assert (cell == LOA_CELL_BLACK || cell == LOA_CELL_WHITE);
+ assert (board->cells[x][y] == LOA_CELL_EMPTY);
+
+ board->col_pieces[x]++;
+ board->row_pieces[y]++;
+ board->diag_grave_pieces[_grave_index (x, y)]++;
+ board->diag_acute_pieces[_acute_index (x, y)]++;
+
+ board->num_pieces[cell]++;
+
+ board->cells[x][y] = cell;
+}
+
+static loa_cell_t
+loa_board_remove_piece (loa_board_t *board, int x, int y)
+{
+ loa_cell_t cell;
+
+ cell = board->cells[x][y];
+
+ if (cell == LOA_CELL_EMPTY)
+ return LOA_CELL_EMPTY;
+
+ board->col_pieces[x]--;
+ board->row_pieces[y]--;
+ board->diag_grave_pieces[_grave_index (x, y)]--;
+ board->diag_acute_pieces[_acute_index (x, y)]--;
+
+ board->num_pieces[cell]--;
+
+ board->cells[x][y] = LOA_CELL_EMPTY;
+
+ return cell;
+}
+
+void
+loa_board_init (loa_board_t *board)
+{
+ int i, x, y;
+
+ for (x = 0; x < LOA_BOARD_SIZE; x++)
+ for (y = 0; y < LOA_BOARD_SIZE; y++)
+ board->cells[x][y] = LOA_CELL_EMPTY;
+
+ board->num_pieces[LOA_CELL_BLACK] = 0;
+ board->num_pieces[LOA_CELL_WHITE] = 0;
+
+ for (i = 0; i < LOA_BOARD_SIZE; i++) {
+ board->row_pieces[i] = 0;
+ board->col_pieces[i] = 0;
+ }
+
+ for (i = 0; i < LOA_DIAG_ARRAY_SIZE; i++) {
+ board->diag_grave_pieces[i] = 0;
+ board->diag_acute_pieces[i] = 0;
+ }
+
+ for (i = 1; i < LOA_BOARD_SIZE - 1; i++) {
+ loa_board_add_piece (board, i, 0, LOA_CELL_BLACK);
+ loa_board_add_piece (board, i, LOA_BOARD_SIZE - 1, LOA_CELL_BLACK);
+ loa_board_add_piece (board, 0, i, LOA_CELL_WHITE);
+ loa_board_add_piece (board, LOA_BOARD_SIZE - 1, i, LOA_CELL_WHITE);
+ }
+
+ board->player = LOA_PLAYER_BLACK;
+}
+
+static int
+loa_board_group_size_recursive (loa_board_t *board, int x, int y,
+ loa_cell_t cell,
+ uint64_t *visited)
+{
+ uint64_t bit;
+
+ if (x < 0 || y < 0)
+ return 0;
+
+ if (x >= LOA_BOARD_SIZE || y >= LOA_BOARD_SIZE)
+ return 0;
+
+ bit = 1ll << (x * LOA_BOARD_SIZE + y);
+ if (*visited & bit)
+ return 0;
+
+ *visited |= bit;
+
+ if (board->cells[x][y] != cell)
+ return 0;
+
+ return 1 +
+ loa_board_group_size_recursive (board, x-1, y-1, cell, visited) +
+ loa_board_group_size_recursive (board, x-1, y , cell, visited) +
+ loa_board_group_size_recursive (board, x-1, y+1, cell, visited) +
+ loa_board_group_size_recursive (board, x , y-1, cell, visited) +
+ loa_board_group_size_recursive (board, x , y , cell, visited) +
+ loa_board_group_size_recursive (board, x , y+1, cell, visited) +
+ loa_board_group_size_recursive (board, x+1, y-1, cell, visited) +
+ loa_board_group_size_recursive (board, x+1, y , cell, visited) +
+ loa_board_group_size_recursive (board, x+1, y+1, cell, visited);
+}
+
+static int
+loa_board_group_size (loa_board_t *board, int x, int y)
+{
+ uint64_t visited = 0ll;
+ loa_cell_t cell = board->cells[x][y];
+
+ return loa_board_group_size_recursive (board, x, y, cell, &visited);
+}
+
+int
+loa_board_is_won (loa_board_t *board, int x, int y)
+{
+ loa_cell_t cell = board->cells[x][y];
+
+ if (cell == LOA_CELL_EMPTY)
+ return 0;
+
+ if (loa_board_group_size (board, x, y) == board->num_pieces[cell])
+ return 1;
+
+ return 0;
+}
+
+static loa_bool_t
+loa_board_move_legal (loa_board_t *board,
+ int x1, int y1,
+ int x2, int y2,
+ char **error)
+{
+ int x, y;
+ int dx, dy;
+ int step_x, step_y;
+
+ if (x1 < 0 || y1 < 0 || x1 >= LOA_BOARD_SIZE || y1 >= LOA_BOARD_SIZE) {
+ *error = "Invalid coordinates (not on board)";
+ return FALSE;
+ }
+
+
+ if (board->cells[x1][y1] == LOA_CELL_EMPTY) {
+ *error = "There is no piece there to move";
+ return FALSE;
+ }
+
+ if (board->cells[x1][y1] != board->player) {
+ *error = "You cannot move your opponent's piece";
+ return FALSE;
+ }
+
+ if (board->cells[x2][y2] == board->cells[x1][y1]) {
+ *error = "You cannot capture your own piece";
+ return FALSE;
+ }
+
+ dx = x2 - x1;
+ dy = y2 - y1;
+
+ /* Here's the meat of Lines of Action legaility: Does the distance
+ * moved exactly match the number of pieces (of either color) in
+ * the row, column, or diagonal of the movement. */
+ if (dx == 0) {
+ /* Column */
+ if (abs (dy) != board->col_pieces[x1]) {
+ *error = "The move distance does not match the number of pieces in that column";
+ return FALSE;
+ }
+ } else if (dy == 0) {
+ /* Row */
+ if (abs (dx) != board->row_pieces[y1]) {
+ *error = "The move distance does not match the number of pieces in that row";
+ return FALSE;
+ }
+ } else {
+ if (abs (dx) != abs (dy)) {
+ *error = "That move is not in a row, column, or diagonal";
+ return FALSE;
+ }
+ /* Diagonal */
+ if ((dx > 0) == (dy > 0)) {
+ if (abs (dx) != board->diag_grave_pieces[_grave_index (x1, y1)]) {
+ *error = "The move distance does not match the number of pieces in that diagonal";
+ return FALSE;
+ }
+ } else {
+ if (abs (dx) != board->diag_acute_pieces[_acute_index (x1, y1)]) {
+ *error = "The move distance does not match the number of pieces in that diagonal";
+ return FALSE;
+ }
+ }
+ }
+
+ /* Finally, we have to ensure that no opponent pieces are being
+ * jumped. */
+ step_x = dx ? ((dx < 0) ? -1 : +1) : 0;
+ step_y = dy ? ((dy < 0) ? -1 : +1) : 0;
+ for (x = x1 + step_x, y = y1 + step_y;
+ x != x2 || y != y2;
+ x += step_x, y += step_y)
+ {
+ if (board->cells[x][y] != LOA_CELL_EMPTY &&
+ board->cells[x][y] != board->cells[x1][y1])
+ {
+ *error = "You cannot jump an opponent's piece";
+ return FALSE;
+ }
+ }
+
+ return TRUE;
+}
+
+static void
+loa_board_next_player (loa_board_t *board)
+{
+ if (board->player == LOA_PLAYER_BLACK)
+ board->player = LOA_PLAYER_WHITE;
+ else
+ board->player = LOA_PLAYER_BLACK;
+}
+
+/* XXX: Should check for a legal move for the current player and
+ * return FALSE in that case, (that is, it should be illegal to pass
+ * if there's a legal move available). */
+int
+loa_board_pass (loa_board_t *board)
+{
+ loa_board_next_player (board);
+
+ return TRUE;
+}
+
+int
+loa_board_move (loa_board_t *board,
+ int x1, int y1,
+ int x2, int y2,
+ char **error)
+{
+ loa_cell_t cell;
+
+ if (! loa_board_move_legal (board, x1, y1, x2, y2, error))
+ return FALSE;
+
+ cell = loa_board_remove_piece (board, x1, y1);
+ loa_board_remove_piece (board, x2, y2);
+ loa_board_add_piece (board, x2, y2, cell);
+
+ loa_board_next_player (board);
+
+ return TRUE;
+}
+
+/* A few different ideas for displaying boards:
+ *
+ * 8│ │●│●│●│●│●│●│ | 8| |*|*|*|*|*|*| |
+ * 7│○│ │ │ │ │ │ │○| 7|o| | | | | | |o|
+ * 6│○│ │ │ │ │ │ │○| 6|o| | | | | | |o|
+ * 5│○│ │ │ │ │ │ │○| 5|o| | | | | | |o|
+ * 4│○│ │ │ │ │ │ │○| 4|o| | | | | | |o|
+ * 3│○│ │ │ │ │ │ │○| 3|o| | | | | | |o|
+ * 2│○│ │ │ │ │ │ │○| 2|o| | | | | | |o|
+ * 1│ │●│●│●│●│●│●│ | 1| |*|*|*|*|*|*| |
+ * A B C D E F G H A B C D E F G H
+ *
+ * ┌───┬───┬───┬───┬───┬───┬───┬───┐ -------------------------------
+ * 8│ │ ● │ ● │ ● │ ● │ ● │ ● │ │ 8| | * | * | * | * | * | * | |
+ * ├───┼───┼───┼───┼───┼───┼───┼───┤ |---+---+---+---+---+---+---+---|
+ * 7│ ○ │ │ │ │ │ │ │ ○ │ 7| o | | | | | | | o |
+ * ├───┼───┼───┼───┼───┼───┼───┼───┤ |---+---+---+---+---+---+---+---|
+ * 6│ ○ │ │ │ │ │ │ │ ○ │ 6| o | | | | | | | o |
+ * ├───┼───┼───┼───┼───┼───┼───┼───┤ |---+---+---+---+---+---+---+---|
+ * 5│ ○ │ │ │ │ │ │ │ ○ │ 5| o | | | | | | | o |
+ * ├───┼───┼───┼───┼───┼───┼───┼───┤ |---+---+---+---+---+---+---+---|
+ * 4│ ○ │ │ │ │ │ │ │ ○ │ 4| o | | | | | | | o |
+ * ├───┼───┼───┼───┼───┼───┼───┼───┤ |---+---+---+---+---+---+---+---|
+ * 3│ ○ │ │ │ │ │ │ │ ○ │ 3| o | | | | | | | o |
+ * ├───┼───┼───┼───┼───┼───┼───┼───┤ |---+---+---+---+---+---+---+---|
+ * 2│ ○ │ │ │ │ │ │ │ ○ │ 2| o | | | | | | | o |
+ * ├───┼───┼───┼───┼───┼───┼───┼───┤ |---+---+---+---+---+---+---+---|
+ * 1│ │ ● │ ● │ ● │ ● │ ● │ ● │ │ 1| | * | * | * | * | * | * | |
+ * └───┴───┴───┴───┴───┴───┴───┴───┘ -------------------------------
+ * A B C D E F G H A B C D E F G H
+ */
+char *
+loa_board_to_string (loa_board_t *board)
+{
+ int x, y;
+ /* In order of BLACK, WHITE, EMPTY */
+ const char* cell_strings[] = {"●","○"," "};
+ const char board_header[] = "┌───┬───┬───┬───┬───┬───┬───┬───┐";
+ const char row_header[] = "│ ";
+ const char cell_separator[] = " │ ";
+ const char row_footer[] = " │";
+ const char row_separator[] = "├───┼───┼───┼───┼───┼───┼───┼───┤";
+ const char board_footer[] = "└───┴───┴───┴───┴───┴───┴───┴───┘";
+ char *board_string = g_strdup ("");
+
+#define APPEND(str) do { \
+ char *_new = g_strconcat (board_string, (str), NULL); \
+ free (board_string); \
+ board_string = _new; \
+} while (0)
+
+#define APPENDF(format, ...) do { \
+ char *str = g_strdup_printf (format, ## __VA_ARGS__); \
+ APPEND (str); \
+ free (str); \
+} while (0)
+
+ APPENDF (" %s\n", board_header);
+ for (y = 0; y < LOA_BOARD_SIZE; y++) {
+ APPENDF ("%d%s", LOA_BOARD_SIZE - y, row_header);
+ for (x = 0; x < LOA_BOARD_SIZE; x++) {
+ APPENDF ("%s", cell_strings[board->cells[x][y]]);
+ if (x != LOA_BOARD_SIZE - 1)
+ APPENDF ("%s", cell_separator);
+ }
+ APPENDF ("%s\n", row_footer);
+ if (y != LOA_BOARD_SIZE -1)
+ APPENDF (" %s\n", row_separator);
+ }
+ APPENDF (" %s\n", board_footer);
+
+ APPENDF (" ");
+ for (x = 0; x < LOA_BOARD_SIZE; x++) {
+ APPENDF ("%c", 'A' + x);
+ if (x != LOA_BOARD_SIZE - 1)
+ APPENDF (" ");
+ }
+ APPENDF ("\n");
+
+ return board_string;
+}
projects / loa / commitdiff