| 1 | /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *\ |
| 2 | * This is GNU Go, a Go program. Contact gnugo@gnu.org, or see * |
| 3 | * http://www.gnu.org/software/gnugo/ for more information. * |
| 4 | * * |
| 5 | * Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, * |
| 6 | * 2008 and 2009 by the Free Software Foundation. * |
| 7 | * * |
| 8 | * This program is free software; you can redistribute it and/or * |
| 9 | * modify it under the terms of the GNU General Public License as * |
| 10 | * published by the Free Software Foundation - version 3 or * |
| 11 | * (at your option) any later version. * |
| 12 | * * |
| 13 | * This program is distributed in the hope that it will be useful, * |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of * |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * |
| 16 | * GNU General Public License in file COPYING for more details. * |
| 17 | * * |
| 18 | * You should have received a copy of the GNU General Public * |
| 19 | * License along with this program; if not, write to the Free * |
| 20 | * Software Foundation, Inc., 51 Franklin Street, Fifth Floor, * |
| 21 | * Boston, MA 02111, USA. * |
| 22 | \* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| 23 | |
| 24 | |
| 25 | /* The functions in this file implements a go board with incremental |
| 26 | * update of strings and liberties. |
| 27 | * |
| 28 | * See the Texinfo documentation (Utility Functions: Incremental Board) |
| 29 | * for an introduction. |
| 30 | */ |
| 31 | |
| 32 | #include "board.h" |
| 33 | #include "hash.h" |
| 34 | #include "sgftree.h" |
| 35 | #include "gg_utils.h" |
| 36 | |
| 37 | #include <stdio.h> |
| 38 | #include <string.h> |
| 39 | #include <stdlib.h> |
| 40 | #include <stdarg.h> |
| 41 | |
| 42 | |
| 43 | /* This can be used for internal checks w/in board.c that should |
| 44 | * typically not be necessary (for speed). |
| 45 | */ |
| 46 | #if 1 |
| 47 | #define PARANOID1(x, pos) ASSERT1(x, pos) |
| 48 | #else |
| 49 | #define PARANOID1(x, pos) |
| 50 | #endif |
| 51 | |
| 52 | |
| 53 | /* ================================================================ */ |
| 54 | /* data structures */ |
| 55 | /* ================================================================ */ |
| 56 | |
| 57 | |
| 58 | /* Incremental string data. */ |
| 59 | struct string_data { |
| 60 | int color; /* Color of string, BLACK or WHITE */ |
| 61 | int size; /* Number of stones in string. */ |
| 62 | int origin; /* Coordinates of "origin", i.e. */ |
| 63 | /* "upper left" stone. */ |
| 64 | int liberties; /* Number of liberties. */ |
| 65 | int neighbors; /* Number of neighbor strings */ |
| 66 | int mark; /* General purpose mark. */ |
| 67 | }; |
| 68 | |
| 69 | struct string_liberties_data { |
| 70 | int list[MAX_LIBERTIES]; /* Coordinates of liberties. */ |
| 71 | }; |
| 72 | |
| 73 | struct string_neighbors_data { |
| 74 | int list[MAXCHAIN]; /* List of neighbor string numbers. */ |
| 75 | }; |
| 76 | |
| 77 | /* we keep the address and the old value */ |
| 78 | struct change_stack_entry { |
| 79 | int *address; |
| 80 | int value; |
| 81 | }; |
| 82 | |
| 83 | /* we keep the address and the old value */ |
| 84 | struct vertex_stack_entry { |
| 85 | Intersection *address; |
| 86 | int value; |
| 87 | }; |
| 88 | |
| 89 | |
| 90 | /* Experimental results show that the average number of change stack |
| 91 | * entries per move usually is in the 20-30 range and very seldom |
| 92 | * exceeds 40. But since we have no way to recover from running out of |
| 93 | * stack space, we allocate with a substantial safety margin. |
| 94 | */ |
| 95 | #define STACK_SIZE 80 * MAXSTACK |
| 96 | |
| 97 | |
| 98 | #define CLEAR_STACKS() do { \ |
| 99 | change_stack_pointer = change_stack; \ |
| 100 | vertex_stack_pointer = vertex_stack; \ |
| 101 | VALGRIND_MAKE_WRITABLE(change_stack, sizeof(change_stack)); \ |
| 102 | VALGRIND_MAKE_WRITABLE(vertex_stack, sizeof(vertex_stack)); \ |
| 103 | } while (0) |
| 104 | |
| 105 | /* Begin a record : address == NULL */ |
| 106 | #define BEGIN_CHANGE_RECORD()\ |
| 107 | ((change_stack_pointer++)->address = NULL,\ |
| 108 | (vertex_stack_pointer++)->address = NULL) |
| 109 | |
| 110 | /* Save a value : store the address and the value in the stack */ |
| 111 | #define PUSH_VALUE(v)\ |
| 112 | (change_stack_pointer->address = &(v),\ |
| 113 | (change_stack_pointer++)->value = (v)) |
| 114 | |
| 115 | /* Save a board value : store the address and the value in the stack */ |
| 116 | #define PUSH_VERTEX(v)\ |
| 117 | (vertex_stack_pointer->address = &(v),\ |
| 118 | (vertex_stack_pointer++)->value = (v)) |
| 119 | |
| 120 | #define POP_MOVE()\ |
| 121 | while ((--change_stack_pointer)->address)\ |
| 122 | *(change_stack_pointer->address) =\ |
| 123 | change_stack_pointer->value |
| 124 | |
| 125 | |
| 126 | #define POP_VERTICES()\ |
| 127 | while ((--vertex_stack_pointer)->address)\ |
| 128 | *(vertex_stack_pointer->address) =\ |
| 129 | vertex_stack_pointer->value |
| 130 | |
| 131 | |
| 132 | /* ================================================================ */ |
| 133 | /* static data structures */ |
| 134 | /* ================================================================ */ |
| 135 | |
| 136 | |
| 137 | /* Main array of string information. */ |
| 138 | static struct string_data string[MAX_STRINGS]; |
| 139 | static struct string_liberties_data string_libs[MAX_STRINGS]; |
| 140 | static struct string_neighbors_data string_neighbors[MAX_STRINGS]; |
| 141 | |
| 142 | /* Stacks and stack pointers. */ |
| 143 | static struct change_stack_entry change_stack[STACK_SIZE]; |
| 144 | static struct change_stack_entry *change_stack_pointer; |
| 145 | |
| 146 | static struct vertex_stack_entry vertex_stack[STACK_SIZE]; |
| 147 | static struct vertex_stack_entry *vertex_stack_pointer; |
| 148 | |
| 149 | |
| 150 | /* Index into list of strings. The index is only valid if there is a |
| 151 | * stone at the vertex. |
| 152 | */ |
| 153 | static int string_number[BOARDMAX]; |
| 154 | |
| 155 | |
| 156 | /* The stones in a string are linked together in a cyclic list. |
| 157 | * These are the coordinates to the next stone in the string. |
| 158 | */ |
| 159 | static int next_stone[BOARDMAX]; |
| 160 | |
| 161 | |
| 162 | /* ---------------------------------------------------------------- */ |
| 163 | |
| 164 | |
| 165 | /* Macros to traverse the stones of a string. |
| 166 | * |
| 167 | * Usage: |
| 168 | * int s, pos; |
| 169 | * s = find_the_string() |
| 170 | * pos = FIRST_STONE(s); |
| 171 | * do { |
| 172 | * use_stone(pos); |
| 173 | * pos = NEXT_STONE(pos); |
| 174 | * } while (!BACK_TO_FIRST_STONE(s, pos)); |
| 175 | */ |
| 176 | #define FIRST_STONE(s) \ |
| 177 | (string[s].origin) |
| 178 | |
| 179 | #define NEXT_STONE(pos) \ |
| 180 | (next_stone[pos]) |
| 181 | |
| 182 | #define BACK_TO_FIRST_STONE(s, pos) \ |
| 183 | ((pos) == string[s].origin) |
| 184 | |
| 185 | |
| 186 | /* Assorted useful macros. |
| 187 | * |
| 188 | * Some of them could have been functions but are implemented as |
| 189 | * macros for speed. |
| 190 | */ |
| 191 | |
| 192 | #define LIBERTY(pos) \ |
| 193 | (board[pos] == EMPTY) |
| 194 | |
| 195 | #define UNMARKED_LIBERTY(pos) \ |
| 196 | (board[pos] == EMPTY && ml[pos] != liberty_mark) |
| 197 | |
| 198 | #define MARK_LIBERTY(pos) \ |
| 199 | ml[pos] = liberty_mark |
| 200 | |
| 201 | #define UNMARKED_STRING(pos) \ |
| 202 | (string[string_number[pos]].mark != string_mark) |
| 203 | |
| 204 | /* Note that these two macros are not complementary. Both return |
| 205 | * false if board[pos] != color. |
| 206 | */ |
| 207 | #define UNMARKED_COLOR_STRING(pos, color)\ |
| 208 | (board[pos] == color\ |
| 209 | && string[string_number[pos]].mark != string_mark) |
| 210 | |
| 211 | #define MARKED_COLOR_STRING(pos, color)\ |
| 212 | (board[pos] == color\ |
| 213 | && string[string_number[pos]].mark == string_mark) |
| 214 | |
| 215 | #define MARK_STRING(pos) string[string_number[pos]].mark = string_mark |
| 216 | |
| 217 | #define STRING_AT_VERTEX(pos, s, color)\ |
| 218 | ((board[pos] == color) && string_number[pos] == (s)) |
| 219 | |
| 220 | #define NEIGHBOR_OF_STRING(pos, s, color)\ |
| 221 | (STRING_AT_VERTEX(SOUTH(pos), s, color)\ |
| 222 | || STRING_AT_VERTEX(WEST(pos), s, color)\ |
| 223 | || STRING_AT_VERTEX(NORTH(pos), s, color)\ |
| 224 | || STRING_AT_VERTEX(EAST(pos), s, color)) |
| 225 | |
| 226 | /* These four macros have rather confusing names. It should be read as: |
| 227 | * "(pos) is a neighbor of string (s) of (color) in any direction except |
| 228 | * the specified one". |
| 229 | */ |
| 230 | #define NON_SOUTH_NEIGHBOR_OF_STRING(pos, s, color)\ |
| 231 | (STRING_AT_VERTEX(SOUTH(pos), s, color)\ |
| 232 | || STRING_AT_VERTEX(WEST(pos), s, color)\ |
| 233 | || STRING_AT_VERTEX(EAST(pos), s, color)) |
| 234 | |
| 235 | #define NON_WEST_NEIGHBOR_OF_STRING(pos, s, color)\ |
| 236 | (STRING_AT_VERTEX(WEST(pos), s, color)\ |
| 237 | || STRING_AT_VERTEX(NORTH(pos), s, color)\ |
| 238 | || STRING_AT_VERTEX(SOUTH(pos), s, color)) |
| 239 | |
| 240 | #define NON_NORTH_NEIGHBOR_OF_STRING(pos, s, color)\ |
| 241 | (STRING_AT_VERTEX(NORTH(pos), s, color)\ |
| 242 | || STRING_AT_VERTEX(EAST(pos), s, color)\ |
| 243 | || STRING_AT_VERTEX(WEST(pos), s, color)) |
| 244 | |
| 245 | #define NON_EAST_NEIGHBOR_OF_STRING(pos, s, color)\ |
| 246 | (STRING_AT_VERTEX(EAST(pos), s, color)\ |
| 247 | || STRING_AT_VERTEX(SOUTH(pos), s, color)\ |
| 248 | || STRING_AT_VERTEX(NORTH(pos), s, color)) |
| 249 | |
| 250 | #define LIBERTIES(pos)\ |
| 251 | string[string_number[pos]].liberties |
| 252 | |
| 253 | #define COUNTSTONES(pos) \ |
| 254 | string[string_number[pos]].size |
| 255 | |
| 256 | #define ADD_LIBERTY(s, pos)\ |
| 257 | do {\ |
| 258 | if (string[s].liberties < MAX_LIBERTIES)\ |
| 259 | string_libs[s].list[string[s].liberties] = pos;\ |
| 260 | string[s].liberties++;\ |
| 261 | } while (0) |
| 262 | |
| 263 | #define ADD_AND_MARK_LIBERTY(s, pos)\ |
| 264 | do {\ |
| 265 | if (string[s].liberties < MAX_LIBERTIES)\ |
| 266 | string_libs[s].list[string[s].liberties] = pos;\ |
| 267 | string[s].liberties++;\ |
| 268 | ml[pos] = liberty_mark;\ |
| 269 | } while (0) |
| 270 | |
| 271 | #define ADD_NEIGHBOR(s, pos)\ |
| 272 | string_neighbors[s].list[string[s].neighbors++] = string_number[pos] |
| 273 | |
| 274 | #define DO_ADD_STONE(pos, color)\ |
| 275 | do {\ |
| 276 | PUSH_VERTEX(board[pos]);\ |
| 277 | board[pos] = color;\ |
| 278 | hashdata_invert_stone(&board_hash, pos, color);\ |
| 279 | } while (0) |
| 280 | |
| 281 | #define DO_REMOVE_STONE(pos)\ |
| 282 | do {\ |
| 283 | PUSH_VERTEX(board[pos]);\ |
| 284 | hashdata_invert_stone(&board_hash, pos, board[pos]);\ |
| 285 | board[pos] = EMPTY;\ |
| 286 | } while (0) |
| 287 | |
| 288 | |
| 289 | /* ---------------------------------------------------------------- */ |
| 290 | |
| 291 | |
| 292 | |
| 293 | /* Number of the next free string. */ |
| 294 | static int next_string; |
| 295 | |
| 296 | |
| 297 | /* For marking purposes. */ |
| 298 | static int ml[BOARDMAX]; |
| 299 | static int liberty_mark; |
| 300 | static int string_mark; |
| 301 | |
| 302 | |
| 303 | /* Forward declarations. */ |
| 304 | static void really_do_trymove(int pos, int color); |
| 305 | static int do_trymove(int pos, int color, int ignore_ko); |
| 306 | static void undo_trymove(void); |
| 307 | |
| 308 | static int do_approxlib(int pos, int color, int maxlib, int *libs); |
| 309 | static int slow_approxlib(int pos, int color, int maxlib, int *libs); |
| 310 | static int do_accuratelib(int pos, int color, int maxlib, int *libs); |
| 311 | |
| 312 | static int is_superko_violation(int pos, int color, enum ko_rules type); |
| 313 | |
| 314 | static void new_position(void); |
| 315 | static int propagate_string(int stone, int str); |
| 316 | static void find_liberties_and_neighbors(int s); |
| 317 | static int do_remove_string(int s); |
| 318 | static void do_commit_suicide(int pos, int color); |
| 319 | static void do_play_move(int pos, int color); |
| 320 | |
| 321 | static int komaster, kom_pos; |
| 322 | |
| 323 | |
| 324 | /* Statistics. */ |
| 325 | static int trymove_counter = 0; |
| 326 | |
| 327 | /* Coordinates for the eight directions, ordered |
| 328 | * south, west, north, east, southwest, northwest, northeast, southeast. |
| 329 | */ |
| 330 | int deltai[8] = { 1, 0, -1, 0, 1, -1, -1, 1}; |
| 331 | int deltaj[8] = { 0, -1, 0, 1, -1, -1, 1, 1}; |
| 332 | int delta[8] = { NS, -1, -NS, 1, NS-1, -NS-1, -NS+1, NS+1}; |
| 333 | |
| 334 | |
| 335 | /* ================================================================ */ |
| 336 | /* Board initialization */ |
| 337 | /* ================================================================ */ |
| 338 | |
| 339 | /* |
| 340 | * Save board state. |
| 341 | */ |
| 342 | |
| 343 | void |
| 344 | store_board(struct board_state *state) |
| 345 | { |
| 346 | int k; |
| 347 | |
| 348 | gg_assert(stackp == 0); |
| 349 | |
| 350 | state->board_size = board_size; |
| 351 | |
| 352 | memcpy(state->board, board, sizeof(board)); |
| 353 | memcpy(state->initial_board, initial_board, sizeof(initial_board)); |
| 354 | |
| 355 | state->board_ko_pos = board_ko_pos; |
| 356 | state->white_captured = white_captured; |
| 357 | state->black_captured = black_captured; |
| 358 | |
| 359 | state->initial_board_ko_pos = initial_board_ko_pos; |
| 360 | state->initial_white_captured = initial_white_captured; |
| 361 | state->initial_black_captured = initial_black_captured; |
| 362 | |
| 363 | state->move_history_pointer = move_history_pointer; |
| 364 | for (k = 0; k < move_history_pointer; k++) { |
| 365 | state->move_history_color[k] = move_history_color[k]; |
| 366 | state->move_history_pos[k] = move_history_pos[k]; |
| 367 | state->move_history_hash[k] = move_history_hash[k]; |
| 368 | } |
| 369 | |
| 370 | state->komi = komi; |
| 371 | state->handicap = handicap; |
| 372 | state->move_number = movenum; |
| 373 | } |
| 374 | |
| 375 | |
| 376 | /* |
| 377 | * Restore a saved board state. |
| 378 | */ |
| 379 | |
| 380 | void |
| 381 | restore_board(struct board_state *state) |
| 382 | { |
| 383 | int k; |
| 384 | |
| 385 | gg_assert(stackp == 0); |
| 386 | |
| 387 | board_size = state->board_size; |
| 388 | |
| 389 | memcpy(board, state->board, sizeof(board)); |
| 390 | memcpy(initial_board, state->initial_board, sizeof(initial_board)); |
| 391 | |
| 392 | board_ko_pos = state->board_ko_pos; |
| 393 | white_captured = state->white_captured; |
| 394 | black_captured = state->black_captured; |
| 395 | |
| 396 | initial_board_ko_pos = state->initial_board_ko_pos; |
| 397 | initial_white_captured = state->initial_white_captured; |
| 398 | initial_black_captured = state->initial_black_captured; |
| 399 | |
| 400 | move_history_pointer = state->move_history_pointer; |
| 401 | for (k = 0; k < move_history_pointer; k++) { |
| 402 | move_history_color[k] = state->move_history_color[k]; |
| 403 | move_history_pos[k] = state->move_history_pos[k]; |
| 404 | move_history_hash[k] = state->move_history_hash[k]; |
| 405 | } |
| 406 | |
| 407 | komi = state->komi; |
| 408 | handicap = state->handicap; |
| 409 | movenum = state->move_number; |
| 410 | |
| 411 | hashdata_recalc(&board_hash, board, board_ko_pos); |
| 412 | new_position(); |
| 413 | } |
| 414 | |
| 415 | |
| 416 | /* |
| 417 | * Clear the internal board. |
| 418 | */ |
| 419 | |
| 420 | void |
| 421 | clear_board(void) |
| 422 | { |
| 423 | int k; |
| 424 | |
| 425 | gg_assert(board_size > 0 && board_size <= MAX_BOARD); |
| 426 | |
| 427 | memset(board, EMPTY, sizeof(board)); |
| 428 | memset(initial_board, EMPTY, sizeof(initial_board)); |
| 429 | for (k = 0; k < BOARDSIZE; k++) { |
| 430 | if (!ON_BOARD2(I(k), J(k))) { |
| 431 | board[k] = GRAY; |
| 432 | initial_board[k] = GRAY; |
| 433 | } |
| 434 | } |
| 435 | |
| 436 | board_ko_pos = NO_MOVE; |
| 437 | white_captured = 0; |
| 438 | black_captured = 0; |
| 439 | |
| 440 | komaster = EMPTY; |
| 441 | kom_pos = NO_MOVE; |
| 442 | |
| 443 | initial_board_ko_pos = NO_MOVE; |
| 444 | initial_white_captured = 0; |
| 445 | initial_black_captured = 0; |
| 446 | |
| 447 | move_history_pointer = 0; |
| 448 | movenum = 0; |
| 449 | |
| 450 | handicap = 0; |
| 451 | |
| 452 | hashdata_recalc(&board_hash, board, board_ko_pos); |
| 453 | new_position(); |
| 454 | } |
| 455 | |
| 456 | /* Test the integrity of the gray border. */ |
| 457 | int |
| 458 | test_gray_border(void) |
| 459 | { |
| 460 | int k; |
| 461 | |
| 462 | gg_assert(board_size > 0 && board_size <= MAX_BOARD); |
| 463 | |
| 464 | for (k = 0; k < BOARDSIZE; k++) |
| 465 | if (!ON_BOARD2(I(k), J(k))) |
| 466 | if (board[k] != GRAY) |
| 467 | return k; |
| 468 | |
| 469 | return -1; |
| 470 | } |
| 471 | |
| 472 | |
| 473 | /* ================================================================ */ |
| 474 | /* Temporary moves */ |
| 475 | /* ================================================================ */ |
| 476 | |
| 477 | |
| 478 | /* Stack of trial moves to get to current |
| 479 | * position and which color made them. Perhaps |
| 480 | * this should be one array of a structure |
| 481 | */ |
| 482 | static int stack[MAXSTACK]; |
| 483 | static int move_color[MAXSTACK]; |
| 484 | |
| 485 | static Hash_data board_hash_stack[MAXSTACK]; |
| 486 | |
| 487 | /* |
| 488 | * trymove pushes the position onto the stack, and makes a move |
| 489 | * at pos of color. Returns one if the move is legal. The |
| 490 | * stack pointer is only incremented if the move is legal. |
| 491 | * |
| 492 | * The way to use this is: |
| 493 | * |
| 494 | * if (trymove(...)) { |
| 495 | * ... |
| 496 | * popgo(); |
| 497 | * } |
| 498 | * |
| 499 | * The message can be written as a comment to an sgf file using |
| 500 | * sgfdump(). str can be NO_MOVE if it is not needed but otherwise |
| 501 | * the location of str is included in the comment. |
| 502 | */ |
| 503 | |
| 504 | int |
| 505 | trymove(int pos, int color, const char *message, int str) |
| 506 | { |
| 507 | UNUSED(str); |
| 508 | /* Do the real work elsewhere. */ |
| 509 | if (!do_trymove(pos, color, 0)) |
| 510 | return 0; |
| 511 | |
| 512 | /* Store the move in an sgf tree if one is available. */ |
| 513 | if (sgf_dumptree) { |
| 514 | char buf[100]; |
| 515 | |
| 516 | if (message == NULL) |
| 517 | message = "UNKNOWN"; |
| 518 | |
| 519 | if (pos == NO_MOVE) { |
| 520 | if (komaster != EMPTY) |
| 521 | gg_snprintf(buf, 100, "%s (variation %d, hash %s, komaster %s:%s)", |
| 522 | message, count_variations, hashdata_to_string(&board_hash), |
| 523 | color_to_string(komaster), location_to_string(kom_pos)); |
| 524 | else |
| 525 | gg_snprintf(buf, 100, "%s (variation %d, hash %s)", message, |
| 526 | count_variations, hashdata_to_string(&board_hash)); |
| 527 | } |
| 528 | else { |
| 529 | if (komaster != EMPTY) |
| 530 | gg_snprintf(buf, 100, |
| 531 | "%s at %s (variation %d, hash %s, komaster %s:%s)", |
| 532 | message, location_to_string(pos), count_variations, |
| 533 | hashdata_to_string(&board_hash), |
| 534 | color_to_string(komaster), |
| 535 | location_to_string(kom_pos)); |
| 536 | else |
| 537 | gg_snprintf(buf, 100, "%s at %s (variation %d, hash %s)", |
| 538 | message, location_to_string(pos), count_variations, |
| 539 | hashdata_to_string(&board_hash)); |
| 540 | } |
| 541 | sgftreeAddPlayLast(sgf_dumptree, color, I(pos), J(pos)); |
| 542 | sgftreeAddComment(sgf_dumptree, buf); |
| 543 | } |
| 544 | |
| 545 | if (count_variations) |
| 546 | count_variations++; |
| 547 | stats.nodes++; |
| 548 | |
| 549 | return 1; |
| 550 | } |
| 551 | |
| 552 | |
| 553 | /* |
| 554 | * tryko pushes the position onto the stack, and makes a move |
| 555 | * at (pos) of (color). The move is allowed even if it is an |
| 556 | * illegal ko capture. It is to be imagined that (color) has |
| 557 | * made an intervening ko threat which was answered and now |
| 558 | * the continuation is to be explored. |
| 559 | * |
| 560 | * Return 1 if the move is legal with the above caveat. Returns |
| 561 | * zero if it is not legal because of suicide. |
| 562 | */ |
| 563 | |
| 564 | int |
| 565 | tryko(int pos, int color, const char *message) |
| 566 | { |
| 567 | /* Do the real work elsewhere. */ |
| 568 | if (!do_trymove(pos, color, 1)) |
| 569 | return 0; |
| 570 | |
| 571 | if (sgf_dumptree) { |
| 572 | char buf[100]; |
| 573 | if (message == NULL) |
| 574 | message = "UNKNOWN"; |
| 575 | if (komaster != EMPTY) |
| 576 | gg_snprintf(buf, 100, "tryko: %s (variation %d, %s, komaster %s:%s)", |
| 577 | message, count_variations, hashdata_to_string(&board_hash), |
| 578 | color_to_string(komaster), location_to_string(kom_pos)); |
| 579 | else |
| 580 | gg_snprintf(buf, 100, "tryko: %s (variation %d, %s)", message, |
| 581 | count_variations, hashdata_to_string(&board_hash)); |
| 582 | |
| 583 | /* Add two pass moves to the SGF output to simulate the ko threat |
| 584 | * and the answer. |
| 585 | * |
| 586 | * The reason we add these is that certain SGF viewers, including |
| 587 | * Cgoban 1, won't properly display variations with illegal ko |
| 588 | * captures. SGF FF[4] compliant browsers should have no problem |
| 589 | * with this, though. |
| 590 | */ |
| 591 | sgftreeAddPlayLast(sgf_dumptree, color, -1, -1); |
| 592 | sgftreeAddComment(sgf_dumptree, "tenuki (ko threat)"); |
| 593 | sgftreeAddPlayLast(sgf_dumptree, OTHER_COLOR(color), -1, -1); |
| 594 | sgftreeAddComment(sgf_dumptree, "tenuki (answers ko threat)"); |
| 595 | |
| 596 | sgftreeAddPlayLast(sgf_dumptree, color, I(pos), J(pos)); |
| 597 | sgftreeAddComment(sgf_dumptree, buf); |
| 598 | } |
| 599 | |
| 600 | if (count_variations) |
| 601 | count_variations++; |
| 602 | stats.nodes++; |
| 603 | |
| 604 | return 1; |
| 605 | } |
| 606 | |
| 607 | /* Really, really make a temporary move. It is assumed that all |
| 608 | * necessary checks have already been made and likewise that various |
| 609 | * administrative bookkeeping outside of the actual board logic has |
| 610 | * either been done or is not needed. |
| 611 | */ |
| 612 | static void |
| 613 | really_do_trymove(int pos, int color) |
| 614 | { |
| 615 | BEGIN_CHANGE_RECORD(); |
| 616 | PUSH_VALUE(board_ko_pos); |
| 617 | |
| 618 | /* |
| 619 | * FIXME: Do we really have to store board_hash in a stack? |
| 620 | * |
| 621 | * Answer: No, we don't. But for every stone that we add |
| 622 | * or remove, we must call hashdata_invert_stone(). This is |
| 623 | * not difficult per se, but the whole board.c |
| 624 | * will have to be checked, and there is lots of room |
| 625 | * for mistakes. |
| 626 | * |
| 627 | * At the same time, profiling shows that storing the |
| 628 | * hashdata in a stack doesn't take a lot of time, so |
| 629 | * this is not an urgent FIXME. |
| 630 | */ |
| 631 | memcpy(&board_hash_stack[stackp], &board_hash, sizeof(board_hash)); |
| 632 | |
| 633 | if (board_ko_pos != NO_MOVE) |
| 634 | hashdata_invert_ko(&board_hash, board_ko_pos); |
| 635 | |
| 636 | board_ko_pos = NO_MOVE; |
| 637 | |
| 638 | stackp++; |
| 639 | |
| 640 | if (pos != PASS_MOVE) { |
| 641 | PUSH_VALUE(black_captured); |
| 642 | PUSH_VALUE(white_captured); |
| 643 | do_play_move(pos, color); |
| 644 | } |
| 645 | } |
| 646 | |
| 647 | /* |
| 648 | * Do the main work of trymove() and tryko(), i.e. the common parts. |
| 649 | * The ignore_ko flag tells whether an illegal ko capture may be done. |
| 650 | * Return 1 if the move was valid, otherwise 0. |
| 651 | */ |
| 652 | |
| 653 | static int |
| 654 | do_trymove(int pos, int color, int ignore_ko) |
| 655 | { |
| 656 | /* 1. The color must be BLACK or WHITE. */ |
| 657 | gg_assert(color == BLACK || color == WHITE); |
| 658 | |
| 659 | if (pos != PASS_MOVE) { |
| 660 | /* 2. Unless pass, the move must be inside the board. */ |
| 661 | ASSERT_ON_BOARD1(pos); |
| 662 | |
| 663 | /* Update the reading tree shadow. */ |
| 664 | shadow[pos] = 1; |
| 665 | |
| 666 | /* 3. The location must be empty. */ |
| 667 | if (board[pos] != EMPTY) |
| 668 | return 0; |
| 669 | |
| 670 | /* 4. The location must not be the ko point, unless ignore_ko == 1. */ |
| 671 | if (!ignore_ko && pos == board_ko_pos) { |
| 672 | if (board[WEST(pos)] == OTHER_COLOR(color) |
| 673 | || board[EAST(pos)] == OTHER_COLOR(color)) { |
| 674 | return 0; |
| 675 | } |
| 676 | } |
| 677 | |
| 678 | /* 5. Test for suicide. */ |
| 679 | if (is_suicide(pos, color)) |
| 680 | return 0; |
| 681 | } |
| 682 | |
| 683 | /* Check for stack overflow. */ |
| 684 | if (stackp >= MAXSTACK-2) { |
| 685 | fprintf(stderr, |
| 686 | "gnugo: Truncating search. This is beyond my reading ability!\n"); |
| 687 | /* FIXME: Perhaps it's best to just assert here and be done with it? */ |
| 688 | if (0) { |
| 689 | ASSERT1(0 && "trymove stack overflow", pos); |
| 690 | } |
| 691 | #if 0 |
| 692 | if (verbose > 0) { |
| 693 | showboard(0); |
| 694 | dump_stack(); |
| 695 | } |
| 696 | #endif |
| 697 | fflush(stderr); |
| 698 | return 0; |
| 699 | } |
| 700 | |
| 701 | |
| 702 | /* Only count trymove when we do create a new position. */ |
| 703 | trymove_counter++; |
| 704 | |
| 705 | /* So far, so good. Now push the move on the move stack. These are |
| 706 | * needed for dump_stack(). |
| 707 | */ |
| 708 | stack[stackp] = pos; |
| 709 | move_color[stackp] = color; |
| 710 | |
| 711 | really_do_trymove(pos, color); |
| 712 | |
| 713 | return 1; |
| 714 | } |
| 715 | |
| 716 | |
| 717 | /* |
| 718 | * popgo pops the position from the stack. |
| 719 | */ |
| 720 | |
| 721 | void |
| 722 | popgo() |
| 723 | { |
| 724 | undo_trymove(); |
| 725 | |
| 726 | if (sgf_dumptree) { |
| 727 | char buf[100]; |
| 728 | int is_tryko = 0; |
| 729 | char *sgf_comment; |
| 730 | |
| 731 | /* FIXME: Change the sgfGet*Property() interface so that either |
| 732 | * "C" instead of "C " works or the SGFXX symbols are used. |
| 733 | */ |
| 734 | if (sgfGetCharProperty(sgf_dumptree->lastnode, "C ", &sgf_comment) |
| 735 | && strncmp(sgf_comment, "tryko:", 6) == 0) |
| 736 | is_tryko = 1; |
| 737 | |
| 738 | gg_snprintf(buf, 100, "(next variation: %d)", count_variations); |
| 739 | sgftreeAddComment(sgf_dumptree, buf); |
| 740 | sgf_dumptree->lastnode = sgf_dumptree->lastnode->parent; |
| 741 | |
| 742 | /* After tryko() we need to undo two pass nodes too. */ |
| 743 | if (is_tryko) |
| 744 | sgf_dumptree->lastnode = sgf_dumptree->lastnode->parent->parent; |
| 745 | } |
| 746 | } |
| 747 | |
| 748 | |
| 749 | /* Restore board state to the position before the last move. This is |
| 750 | * accomplished by popping everything that was stored on the stacks |
| 751 | * since the last BEGIN_CHANGE_RECORD(). Also stackp is decreased and |
| 752 | * board hash is restored from stack. |
| 753 | * |
| 754 | * This undoes the effects of do_trymove() or really_do_trymove() and |
| 755 | * is appropriate to call instead of popgo() if you have not passed |
| 756 | * through trymove() or tryko(). |
| 757 | */ |
| 758 | |
| 759 | static void |
| 760 | undo_trymove() |
| 761 | { |
| 762 | gg_assert(change_stack_pointer - change_stack <= STACK_SIZE); |
| 763 | |
| 764 | if (0) { |
| 765 | gprintf("Change stack size = %d\n", change_stack_pointer - change_stack); |
| 766 | gprintf("Vertex stack size = %d\n", vertex_stack_pointer - vertex_stack); |
| 767 | } |
| 768 | |
| 769 | POP_MOVE(); |
| 770 | POP_VERTICES(); |
| 771 | |
| 772 | stackp--; |
| 773 | memcpy(&board_hash, &(board_hash_stack[stackp]), sizeof(board_hash)); |
| 774 | } |
| 775 | |
| 776 | |
| 777 | |
| 778 | /* |
| 779 | * dump_stack() for use under gdb prints the move stack. |
| 780 | */ |
| 781 | |
| 782 | void |
| 783 | dump_stack(void) |
| 784 | { |
| 785 | do_dump_stack(); |
| 786 | |
| 787 | #if !TRACE_READ_RESULTS |
| 788 | if (count_variations) |
| 789 | gprintf("%o (variation %d)", count_variations-1); |
| 790 | #else |
| 791 | gprintf("%o (%s)", hashdata_to_string(&board_hash)); |
| 792 | #endif |
| 793 | |
| 794 | gprintf("%o\n"); |
| 795 | fflush(stderr); |
| 796 | } |
| 797 | |
| 798 | /* Bare bones of dump_stack(). */ |
| 799 | void |
| 800 | do_dump_stack(void) |
| 801 | { |
| 802 | int n; |
| 803 | |
| 804 | for (n = 0; n < stackp; n++) |
| 805 | gprintf("%o%s:%1m ", move_color[n] == BLACK ? "B" : "W", stack[n]); |
| 806 | } |
| 807 | |
| 808 | /* ================================================================ */ |
| 809 | /* Permanent moves */ |
| 810 | /* ================================================================ */ |
| 811 | |
| 812 | |
| 813 | static void |
| 814 | reset_move_history(void) |
| 815 | { |
| 816 | memcpy(initial_board, board, sizeof(board)); |
| 817 | initial_board_ko_pos = board_ko_pos; |
| 818 | initial_white_captured = white_captured; |
| 819 | initial_black_captured = black_captured; |
| 820 | move_history_pointer = 0; |
| 821 | } |
| 822 | |
| 823 | /* Place a stone on the board and update the board_hash. This operation |
| 824 | * destroys all move history. |
| 825 | */ |
| 826 | |
| 827 | void |
| 828 | add_stone(int pos, int color) |
| 829 | { |
| 830 | ASSERT1(stackp == 0, pos); |
| 831 | ASSERT_ON_BOARD1(pos); |
| 832 | ASSERT1(board[pos] == EMPTY, pos); |
| 833 | |
| 834 | board[pos] = color; |
| 835 | hashdata_invert_stone(&board_hash, pos, color); |
| 836 | reset_move_history(); |
| 837 | new_position(); |
| 838 | } |
| 839 | |
| 840 | |
| 841 | /* Remove a stone from the board and update the board_hash. This |
| 842 | * operation destroys the move history. |
| 843 | */ |
| 844 | |
| 845 | void |
| 846 | remove_stone(int pos) |
| 847 | { |
| 848 | ASSERT1(stackp == 0, pos); |
| 849 | ASSERT_ON_BOARD1(pos); |
| 850 | ASSERT1(IS_STONE(board[pos]), pos); |
| 851 | |
| 852 | hashdata_invert_stone(&board_hash, pos, board[pos]); |
| 853 | board[pos] = EMPTY; |
| 854 | reset_move_history(); |
| 855 | new_position(); |
| 856 | } |
| 857 | |
| 858 | |
| 859 | /* Play a move. Basically the same as play_move() below, but doesn't store |
| 860 | * the move in history list. |
| 861 | * |
| 862 | * Set `update_internals' to zero if you want to play several moves in a |
| 863 | * row to avoid overhead caused by new_position(). Don't forget to call |
| 864 | * it yourself after all the moves have been played. |
| 865 | */ |
| 866 | static void |
| 867 | play_move_no_history(int pos, int color, int update_internals) |
| 868 | { |
| 869 | #if CHECK_HASHING |
| 870 | Hash_data oldkey; |
| 871 | |
| 872 | /* Check the hash table to see if it corresponds to the cumulative one. */ |
| 873 | hashdata_recalc(&oldkey, board, board_ko_pos); |
| 874 | gg_assert(hashdata_is_equal(oldkey, board_hash)); |
| 875 | #endif |
| 876 | |
| 877 | if (board_ko_pos != NO_MOVE) |
| 878 | hashdata_invert_ko(&board_hash, board_ko_pos); |
| 879 | board_ko_pos = NO_MOVE; |
| 880 | |
| 881 | /* If the move is a pass, we can skip some steps. */ |
| 882 | if (pos != PASS_MOVE) { |
| 883 | ASSERT_ON_BOARD1(pos); |
| 884 | ASSERT1(board[pos] == EMPTY, pos); |
| 885 | |
| 886 | /* Do play the move. */ |
| 887 | if (!is_suicide(pos, color)) |
| 888 | do_play_move(pos, color); |
| 889 | else |
| 890 | do_commit_suicide(pos, color); |
| 891 | |
| 892 | #if CHECK_HASHING |
| 893 | /* Check the hash table to see if it equals the previous one. */ |
| 894 | hashdata_recalc(&oldkey, board, board_ko_pos); |
| 895 | gg_assert(hashdata_is_equal(oldkey, board_hash)); |
| 896 | #endif |
| 897 | } |
| 898 | |
| 899 | if (update_internals || next_string == MAX_STRINGS) |
| 900 | new_position(); |
| 901 | else |
| 902 | CLEAR_STACKS(); |
| 903 | } |
| 904 | |
| 905 | /* Load the initial position and replay the first n moves. */ |
| 906 | static void |
| 907 | replay_move_history(int n) |
| 908 | { |
| 909 | int k; |
| 910 | |
| 911 | memcpy(board, initial_board, sizeof(board)); |
| 912 | board_ko_pos = initial_board_ko_pos; |
| 913 | white_captured = initial_white_captured; |
| 914 | black_captured = initial_black_captured; |
| 915 | new_position(); |
| 916 | |
| 917 | for (k = 0; k < n; k++) |
| 918 | play_move_no_history(move_history_pos[k], move_history_color[k], 0); |
| 919 | |
| 920 | new_position(); |
| 921 | } |
| 922 | |
| 923 | /* Play a move. If you want to test for legality you should first call |
| 924 | * is_legal(). This function strictly follows the algorithm: |
| 925 | * 1. Place a stone of given color on the board. |
| 926 | * 2. If there are any adjacent opponent strings without liberties, |
| 927 | * remove them and increase the prisoner count. |
| 928 | * 3. If the newly placed stone is part of a string without liberties, |
| 929 | * remove it and increase the prisoner count. |
| 930 | * |
| 931 | * In spite of the name "permanent move", this move can (usually) be |
| 932 | * unplayed by undo_move(), but it is significantly more costly than |
| 933 | * unplaying a temporary move. There are limitations on the available |
| 934 | * move history, so under certain circumstances the move may not be |
| 935 | * possible to unplay at a later time. |
| 936 | */ |
| 937 | void |
| 938 | play_move(int pos, int color) |
| 939 | { |
| 940 | ASSERT1(stackp == 0, pos); |
| 941 | ASSERT1(color == WHITE || color == BLACK, pos); |
| 942 | ASSERT1(pos == PASS_MOVE || ON_BOARD1(pos), pos); |
| 943 | ASSERT1(pos == PASS_MOVE || board[pos] == EMPTY, pos); |
| 944 | ASSERT1(komaster == EMPTY && kom_pos == NO_MOVE, pos); |
| 945 | |
| 946 | if (move_history_pointer >= MAX_MOVE_HISTORY) { |
| 947 | /* The move history is full. We resolve this by collapsing the |
| 948 | * first about 10% of the moves into the initial position. |
| 949 | */ |
| 950 | int number_collapsed_moves = 1 + MAX_MOVE_HISTORY / 10; |
| 951 | int k; |
| 952 | Intersection saved_board[BOARDSIZE]; |
| 953 | int saved_board_ko_pos = board_ko_pos; |
| 954 | int saved_white_captured = white_captured; |
| 955 | int saved_black_captured = black_captured; |
| 956 | memcpy(saved_board, board, sizeof(board)); |
| 957 | |
| 958 | replay_move_history(number_collapsed_moves); |
| 959 | |
| 960 | memcpy(initial_board, board, sizeof(board)); |
| 961 | initial_board_ko_pos = board_ko_pos; |
| 962 | initial_white_captured = white_captured; |
| 963 | initial_black_captured = black_captured; |
| 964 | |
| 965 | for (k = number_collapsed_moves; k < move_history_pointer; k++) { |
| 966 | move_history_color[k - number_collapsed_moves] = move_history_color[k]; |
| 967 | move_history_pos[k - number_collapsed_moves] = move_history_pos[k]; |
| 968 | move_history_hash[k - number_collapsed_moves] = move_history_hash[k]; |
| 969 | } |
| 970 | move_history_pointer -= number_collapsed_moves; |
| 971 | |
| 972 | memcpy(board, saved_board, sizeof(board)); |
| 973 | board_ko_pos = saved_board_ko_pos; |
| 974 | white_captured = saved_white_captured; |
| 975 | black_captured = saved_black_captured; |
| 976 | new_position(); |
| 977 | } |
| 978 | |
| 979 | move_history_color[move_history_pointer] = color; |
| 980 | move_history_pos[move_history_pointer] = pos; |
| 981 | move_history_hash[move_history_pointer] = board_hash; |
| 982 | if (board_ko_pos != NO_MOVE) |
| 983 | hashdata_invert_ko(&move_history_hash[move_history_pointer], board_ko_pos); |
| 984 | move_history_pointer++; |
| 985 | |
| 986 | play_move_no_history(pos, color, 1); |
| 987 | |
| 988 | movenum++; |
| 989 | } |
| 990 | |
| 991 | |
| 992 | /* Undo n permanent moves. Returns 1 if successful and 0 if it fails. |
| 993 | * If n moves cannot be undone, no move is undone. |
| 994 | */ |
| 995 | int |
| 996 | undo_move(int n) |
| 997 | { |
| 998 | gg_assert(stackp == 0); |
| 999 | |
| 1000 | /* Fail if and only if the move history is too short. */ |
| 1001 | if (move_history_pointer < n) |
| 1002 | return 0; |
| 1003 | |
| 1004 | replay_move_history(move_history_pointer - n); |
| 1005 | move_history_pointer -= n; |
| 1006 | movenum -= n; |
| 1007 | |
| 1008 | return 1; |
| 1009 | } |
| 1010 | |
| 1011 | |
| 1012 | /* Return the last move done by the opponent to color. Both if no move |
| 1013 | * was found or if the last move was a pass, PASS_MOVE is returned. |
| 1014 | */ |
| 1015 | int |
| 1016 | get_last_opponent_move(int color) |
| 1017 | { |
| 1018 | int k; |
| 1019 | |
| 1020 | for (k = move_history_pointer - 1; k >= 0; k--) |
| 1021 | if (move_history_color[k] == OTHER_COLOR(color)) |
| 1022 | return move_history_pos[k]; |
| 1023 | |
| 1024 | return PASS_MOVE; |
| 1025 | } |
| 1026 | |
| 1027 | /* Return the last move done by anyone. Both if no move was found or |
| 1028 | * if the last move was a pass, PASS_MOVE is returned. |
| 1029 | */ |
| 1030 | int |
| 1031 | get_last_move() |
| 1032 | { |
| 1033 | if (move_history_pointer == 0) |
| 1034 | return PASS_MOVE; |
| 1035 | |
| 1036 | return move_history_pos[move_history_pointer - 1]; |
| 1037 | } |
| 1038 | |
| 1039 | /* Return the color of the player doing the last move. If no move was |
| 1040 | * found, EMPTY is returned. |
| 1041 | */ |
| 1042 | int |
| 1043 | get_last_player() |
| 1044 | { |
| 1045 | if (move_history_pointer == 0) |
| 1046 | return EMPTY; |
| 1047 | |
| 1048 | return move_history_color[move_history_pointer - 1]; |
| 1049 | } |
| 1050 | |
| 1051 | |
| 1052 | /* ================================================================ */ |
| 1053 | /* Utility functions */ |
| 1054 | /* ================================================================ */ |
| 1055 | |
| 1056 | |
| 1057 | /* |
| 1058 | * Test if the move is a pass or not. Return 1 if it is. |
| 1059 | */ |
| 1060 | |
| 1061 | int |
| 1062 | is_pass(int pos) |
| 1063 | { |
| 1064 | return pos == 0; |
| 1065 | } |
| 1066 | |
| 1067 | |
| 1068 | /* |
| 1069 | * is_legal(pos, color) determines whether the move (color) at pos is |
| 1070 | * legal. This is for internal use in the engine and always assumes |
| 1071 | * that suicide is allowed and only simple ko restrictions, no |
| 1072 | * superko, regardless of the rules actually used in the game. |
| 1073 | * |
| 1074 | * Use is_allowed_move() if you want to take alternative suicide and |
| 1075 | * ko rules into account. |
| 1076 | */ |
| 1077 | |
| 1078 | int |
| 1079 | is_legal(int pos, int color) |
| 1080 | { |
| 1081 | /* 0. A pass move is always legal. */ |
| 1082 | if (pos == PASS_MOVE) |
| 1083 | return 1; |
| 1084 | |
| 1085 | /* 1. The move must be inside the board. */ |
| 1086 | ASSERT_ON_BOARD1(pos); |
| 1087 | |
| 1088 | /* 2. The location must be empty. */ |
| 1089 | if (board[pos] != EMPTY) |
| 1090 | return 0; |
| 1091 | |
| 1092 | /* 3. The location must not be the ko point. */ |
| 1093 | if (pos == board_ko_pos) { |
| 1094 | /* The ko position is guaranteed to have all neighbors of the |
| 1095 | * same color, or off board. If that color is the same as the |
| 1096 | * move the ko is being filled, which is always allowed. This |
| 1097 | * could be tested with has_neighbor() but here a faster test |
| 1098 | * suffices. |
| 1099 | */ |
| 1100 | if (board[WEST(pos)] == OTHER_COLOR(color) |
| 1101 | || board[EAST(pos)] == OTHER_COLOR(color)) { |
| 1102 | return 0; |
| 1103 | } |
| 1104 | } |
| 1105 | |
| 1106 | /* Check for stack overflow. */ |
| 1107 | if (stackp >= MAXSTACK-2) { |
| 1108 | fprintf(stderr, |
| 1109 | "gnugo: Truncating search. This is beyond my reading ability!\n"); |
| 1110 | /* FIXME: Perhaps it's best to just assert here and be done with it? */ |
| 1111 | if (0) { |
| 1112 | ASSERT1(0 && "is_legal stack overflow", pos); |
| 1113 | } |
| 1114 | return 0; |
| 1115 | } |
| 1116 | |
| 1117 | /* Check for suicide. */ |
| 1118 | if (is_suicide(pos, color)) |
| 1119 | return 0; |
| 1120 | |
| 1121 | return 1; |
| 1122 | } |
| 1123 | |
| 1124 | |
| 1125 | /* |
| 1126 | * is_suicide(pos, color) determines whether the move (color) at |
| 1127 | * (pos) would be a suicide. |
| 1128 | * |
| 1129 | * This is the case if |
| 1130 | * 1. There is no neighboring empty intersection. |
| 1131 | * 2. There is no neighboring opponent string with exactly one liberty. |
| 1132 | * 3. There is no neighboring friendly string with more than one liberty. |
| 1133 | */ |
| 1134 | int |
| 1135 | is_suicide(int pos, int color) |
| 1136 | { |
| 1137 | ASSERT_ON_BOARD1(pos); |
| 1138 | ASSERT1(board[pos] == EMPTY, pos); |
| 1139 | |
| 1140 | /* Check for suicide. */ |
| 1141 | if (LIBERTY(SOUTH(pos)) |
| 1142 | || (ON_BOARD(SOUTH(pos)) |
| 1143 | && ((board[SOUTH(pos)] == color) ^ (LIBERTIES(SOUTH(pos)) == 1)))) |
| 1144 | return 0; |
| 1145 | |
| 1146 | if (LIBERTY(WEST(pos)) |
| 1147 | || (ON_BOARD(WEST(pos)) |
| 1148 | && ((board[WEST(pos)] == color) ^ (LIBERTIES(WEST(pos)) == 1)))) |
| 1149 | return 0; |
| 1150 | |
| 1151 | if (LIBERTY(NORTH(pos)) |
| 1152 | || (ON_BOARD(NORTH(pos)) |
| 1153 | && ((board[NORTH(pos)] == color) ^ (LIBERTIES(NORTH(pos)) == 1)))) |
| 1154 | return 0; |
| 1155 | |
| 1156 | if (LIBERTY(EAST(pos)) |
| 1157 | || (ON_BOARD(EAST(pos)) |
| 1158 | && ((board[EAST(pos)] == color) ^ (LIBERTIES(EAST(pos)) == 1)))) |
| 1159 | return 0; |
| 1160 | |
| 1161 | return 1; |
| 1162 | } |
| 1163 | |
| 1164 | |
| 1165 | /* |
| 1166 | * is_illegal_ko_capture(pos, color) determines whether the move |
| 1167 | * (color) at (pos) would be an illegal ko capture. |
| 1168 | */ |
| 1169 | int |
| 1170 | is_illegal_ko_capture(int pos, int color) |
| 1171 | { |
| 1172 | ASSERT_ON_BOARD1(pos); |
| 1173 | ASSERT1(board[pos] == EMPTY, pos); |
| 1174 | |
| 1175 | return (pos == board_ko_pos |
| 1176 | && ((board[WEST(pos)] == OTHER_COLOR(color)) |
| 1177 | || (board[EAST(pos)] == OTHER_COLOR(color)))); |
| 1178 | } |
| 1179 | |
| 1180 | /* |
| 1181 | * is_allowed_move(int pos, int color) determines whether a move is |
| 1182 | * legal with respect to the suicide and ko rules in play. |
| 1183 | * |
| 1184 | * This function is only valid when stackp == 0 since there is no |
| 1185 | * tracking of superko for trymoves. |
| 1186 | */ |
| 1187 | int |
| 1188 | is_allowed_move(int pos, int color) |
| 1189 | { |
| 1190 | gg_assert(stackp == 0); |
| 1191 | |
| 1192 | /* 1. A pass move is always legal, no matter what. */ |
| 1193 | if (pos == PASS_MOVE) |
| 1194 | return 1; |
| 1195 | |
| 1196 | /* 2. The move must be inside the board. */ |
| 1197 | ASSERT_ON_BOARD1(pos); |
| 1198 | |
| 1199 | /* 3. The location must be empty. */ |
| 1200 | if (board[pos] != EMPTY) |
| 1201 | return 0; |
| 1202 | |
| 1203 | /* 4. Simple ko repetition is only allowed if no ko rule is in use. |
| 1204 | * For superko rules this check is redundant. |
| 1205 | * |
| 1206 | * The ko position is guaranteed to have all neighbors of the |
| 1207 | * same color, or off board. If that color is the same as the |
| 1208 | * move the ko is being filled, which is always allowed. This |
| 1209 | * could be tested with has_neighbor() but here a faster test |
| 1210 | * suffices. |
| 1211 | */ |
| 1212 | if (ko_rule != NONE |
| 1213 | && pos == board_ko_pos |
| 1214 | && (board[WEST(pos)] == OTHER_COLOR(color) |
| 1215 | || board[EAST(pos)] == OTHER_COLOR(color))) |
| 1216 | return 0; |
| 1217 | |
| 1218 | /* 5. Check for suicide. Suicide rule options: |
| 1219 | * FORBIDDEN - No suicides allowed. |
| 1220 | * ALLOWED - Suicide of more than one stone allowed. |
| 1221 | * ALL_ALLOWED - All suicides allowed. |
| 1222 | */ |
| 1223 | if (is_suicide(pos, color)) |
| 1224 | if (suicide_rule == FORBIDDEN |
| 1225 | || (suicide_rule == ALLOWED |
| 1226 | && !has_neighbor(pos, color))) |
| 1227 | return 0; |
| 1228 | |
| 1229 | /* 6. Check for whole board repetitions. The superko options are |
| 1230 | * SIMPLE, NONE - No superko restrictions. |
| 1231 | * PSK - Repetition of a previous position forbidden. |
| 1232 | * SSK - Repetition of a previous position with the same |
| 1233 | * player to move forbidden. |
| 1234 | */ |
| 1235 | if (is_superko_violation(pos, color, ko_rule)) |
| 1236 | return 0; |
| 1237 | |
| 1238 | return 1; |
| 1239 | } |
| 1240 | |
| 1241 | /* Necessary work to set the new komaster state. */ |
| 1242 | static void |
| 1243 | set_new_komaster(int new_komaster) |
| 1244 | { |
| 1245 | PUSH_VALUE(komaster); |
| 1246 | hashdata_invert_komaster(&board_hash, komaster); |
| 1247 | komaster = new_komaster; |
| 1248 | hashdata_invert_komaster(&board_hash, komaster); |
| 1249 | } |
| 1250 | |
| 1251 | /* Necessary work to set the new komaster position. */ |
| 1252 | static void |
| 1253 | set_new_kom_pos(int new_kom_pos) |
| 1254 | { |
| 1255 | PUSH_VALUE(kom_pos); |
| 1256 | hashdata_invert_kom_pos(&board_hash, kom_pos); |
| 1257 | kom_pos = new_kom_pos; |
| 1258 | hashdata_invert_kom_pos(&board_hash, kom_pos); |
| 1259 | } |
| 1260 | |
| 1261 | /* Variation of trymove()/tryko() where ko captures (both conditional |
| 1262 | * and unconditional) must follow a komaster scheme. |
| 1263 | * |
| 1264 | * Historical note: Up to GNU Go 3.4 five different komaster schemes |
| 1265 | * were implemented and could easily be switched between. In GNU Go |
| 1266 | * 3.5.1 four of them were removed to simplify the code and because it |
| 1267 | * no longer seemed interesting to be able to switch. The remaining |
| 1268 | * komaster scheme was previously known as komaster scheme 5 (or V). |
| 1269 | * |
| 1270 | * FIXME: This function could be optimized by integrating the |
| 1271 | * trymove()/tryko() code. |
| 1272 | */ |
| 1273 | |
| 1274 | /* V. Complex scheme, O to move. |
| 1275 | * |
| 1276 | * 1. Komaster is EMPTY. |
| 1277 | * 1a) Unconditional ko capture is allowed. |
| 1278 | * Komaster remains EMPTY if previous move was not a ko capture. |
| 1279 | * Komaster is set to WEAK_KO if previous move was a ko capture |
| 1280 | * and kom_pos is set to the old value of board_ko_pos. |
| 1281 | * 1b) Conditional ko capture is allowed. Komaster is set to O and |
| 1282 | * kom_pos to the location of the ko, where a stone was |
| 1283 | * just removed. |
| 1284 | * |
| 1285 | * 2. Komaster is O: |
| 1286 | * 2a) Only nested ko captures are allowed. Kom_pos is moved to the |
| 1287 | * new removed stone. |
| 1288 | * 2b) If komaster fills the ko at kom_pos then komaster reverts to |
| 1289 | * EMPTY. |
| 1290 | * |
| 1291 | * 3. Komaster is X: |
| 1292 | * Play at kom_pos is not allowed. Any other ko capture |
| 1293 | * is allowed. If O takes another ko, komaster becomes GRAY_X. |
| 1294 | * |
| 1295 | * 4. Komaster is GRAY_O or GRAY_X: |
| 1296 | * Ko captures are not allowed. If the ko at kom_pos is |
| 1297 | * filled then the komaster reverts to EMPTY. |
| 1298 | * |
| 1299 | * 5. Komaster is WEAK_KO: |
| 1300 | * 5a) After a non-ko move komaster reverts to EMPTY. |
| 1301 | * 5b) Unconditional ko capture is only allowed if it is nested ko capture. |
| 1302 | * Komaster is changed to WEAK_X and kom_pos to the old value of |
| 1303 | * board_ko_pos. |
| 1304 | * 5c) Conditional ko capture is allowed according to the rules of 1b. |
| 1305 | */ |
| 1306 | int |
| 1307 | komaster_trymove(int pos, int color, const char *message, int str, |
| 1308 | int *is_conditional_ko, int consider_conditional_ko) |
| 1309 | { |
| 1310 | int other = OTHER_COLOR(color); |
| 1311 | int ko_move; |
| 1312 | int kpos; |
| 1313 | int previous_board_ko_pos = board_ko_pos; |
| 1314 | |
| 1315 | *is_conditional_ko = 0; |
| 1316 | ko_move = is_ko(pos, color, &kpos); |
| 1317 | |
| 1318 | if (ko_move) { |
| 1319 | /* If opponent is komaster we may not capture his ko. */ |
| 1320 | if (komaster == other && pos == kom_pos) |
| 1321 | return 0; |
| 1322 | |
| 1323 | /* If komaster is gray we may not capture ko at all. */ |
| 1324 | if (komaster == GRAY_WHITE || komaster == GRAY_BLACK) |
| 1325 | return 0; |
| 1326 | |
| 1327 | /* If we are komaster, we may only do nested captures. */ |
| 1328 | if (komaster == color && !DIAGONAL_NEIGHBORS(kpos, kom_pos)) |
| 1329 | return 0; |
| 1330 | |
| 1331 | /* If komaster is WEAK_KO, we may only do nested ko capture or |
| 1332 | * conditional ko capture. |
| 1333 | */ |
| 1334 | if (komaster == WEAK_KO) { |
| 1335 | if (pos != board_ko_pos && !DIAGONAL_NEIGHBORS(kpos, kom_pos)) |
| 1336 | return 0; |
| 1337 | } |
| 1338 | } |
| 1339 | |
| 1340 | if (!trymove(pos, color, message, str)) { |
| 1341 | if (!consider_conditional_ko) |
| 1342 | return 0; |
| 1343 | |
| 1344 | if (!tryko(pos, color, message)) |
| 1345 | return 0; /* Suicide. */ |
| 1346 | |
| 1347 | *is_conditional_ko = 1; |
| 1348 | |
| 1349 | /* Conditional ko capture, set komaster parameters. */ |
| 1350 | if (komaster == EMPTY || komaster == WEAK_KO) { |
| 1351 | set_new_komaster(color); |
| 1352 | set_new_kom_pos(kpos); |
| 1353 | return 1; |
| 1354 | } |
| 1355 | } |
| 1356 | |
| 1357 | if (!ko_move) { |
| 1358 | /* If we are komaster, check whether the ko was resolved by the |
| 1359 | * current move. If that is the case, revert komaster to EMPTY. |
| 1360 | * |
| 1361 | * The ko has been resolved in favor of the komaster if it has |
| 1362 | * been filled, or if it is no longer a ko and an opponent move |
| 1363 | * there is suicide. |
| 1364 | */ |
| 1365 | if (((komaster == color |
| 1366 | || (komaster == GRAY_WHITE && color == WHITE) |
| 1367 | || (komaster == GRAY_BLACK && color == BLACK)) |
| 1368 | && (IS_STONE(board[kom_pos]) |
| 1369 | || (!is_ko(kom_pos, other, NULL) |
| 1370 | && is_suicide(kom_pos, other))))) { |
| 1371 | set_new_komaster(EMPTY); |
| 1372 | set_new_kom_pos(NO_MOVE); |
| 1373 | } |
| 1374 | |
| 1375 | if (komaster == WEAK_KO) { |
| 1376 | set_new_komaster(EMPTY); |
| 1377 | set_new_kom_pos(NO_MOVE); |
| 1378 | } |
| 1379 | |
| 1380 | return 1; |
| 1381 | } |
| 1382 | |
| 1383 | if (komaster == other) { |
| 1384 | if (color == WHITE) |
| 1385 | set_new_komaster(GRAY_BLACK); |
| 1386 | else |
| 1387 | set_new_komaster(GRAY_WHITE); |
| 1388 | } |
| 1389 | else if (komaster == color) { |
| 1390 | /* This is where we update kom_pos after a nested capture. */ |
| 1391 | set_new_kom_pos(kpos); |
| 1392 | } |
| 1393 | else { |
| 1394 | /* We can reach here when komaster is EMPTY or WEAK_KO. If previous |
| 1395 | * move was also a ko capture, we now set komaster to WEAK_KO. |
| 1396 | */ |
| 1397 | if (previous_board_ko_pos != NO_MOVE) { |
| 1398 | set_new_komaster(WEAK_KO); |
| 1399 | set_new_kom_pos(previous_board_ko_pos); |
| 1400 | } |
| 1401 | } |
| 1402 | |
| 1403 | return 1; |
| 1404 | } |
| 1405 | |
| 1406 | int |
| 1407 | get_komaster() |
| 1408 | { |
| 1409 | return komaster; |
| 1410 | } |
| 1411 | |
| 1412 | int |
| 1413 | get_kom_pos() |
| 1414 | { |
| 1415 | return kom_pos; |
| 1416 | } |
| 1417 | |
| 1418 | |
| 1419 | /* Determine whether vertex is on the edge. */ |
| 1420 | int |
| 1421 | is_edge_vertex(int pos) |
| 1422 | { |
| 1423 | ASSERT_ON_BOARD1(pos); |
| 1424 | if (!ON_BOARD(SW(pos)) |
| 1425 | || !ON_BOARD(NE(pos))) |
| 1426 | return 1; |
| 1427 | |
| 1428 | return 0; |
| 1429 | } |
| 1430 | |
| 1431 | /* Distance to the edge. */ |
| 1432 | int |
| 1433 | edge_distance(int pos) |
| 1434 | { |
| 1435 | int i = I(pos); |
| 1436 | int j = J(pos); |
| 1437 | ASSERT_ON_BOARD1(pos); |
| 1438 | return gg_min(gg_min(i, board_size-1 - i), gg_min(j, board_size-1 - j)); |
| 1439 | } |
| 1440 | |
| 1441 | |
| 1442 | /* Determine whether vertex is a corner. */ |
| 1443 | int |
| 1444 | is_corner_vertex(int pos) |
| 1445 | { |
| 1446 | ASSERT_ON_BOARD1(pos); |
| 1447 | if ((!ON_BOARD(WEST(pos)) || !ON_BOARD(EAST(pos))) |
| 1448 | && (!ON_BOARD(SOUTH(pos)) || !ON_BOARD(NORTH(pos)))) |
| 1449 | return 1; |
| 1450 | |
| 1451 | return 0; |
| 1452 | } |
| 1453 | |
| 1454 | |
| 1455 | /* Reorientation of point pos. This function could have been |
| 1456 | * implemented using the rotate() function in utils/gg_utils.c but we |
| 1457 | * don't want to make libboard dependent on utils. |
| 1458 | */ |
| 1459 | int |
| 1460 | rotate1(int pos, int rot) |
| 1461 | { |
| 1462 | int bs = board_size - 1; |
| 1463 | int i = I(pos); |
| 1464 | int j = J(pos); |
| 1465 | gg_assert(rot >= 0 && rot < 8); |
| 1466 | |
| 1467 | if (pos == PASS_MOVE) |
| 1468 | return PASS_MOVE; |
| 1469 | |
| 1470 | if (rot == 0) |
| 1471 | return pos; /* identity map */ |
| 1472 | if (rot == 1) |
| 1473 | return POS(bs - j, i); /* rotation over 90 degrees */ |
| 1474 | if (rot == 2) |
| 1475 | return POS(bs - i, bs - j); /* rotation over 180 degrees */ |
| 1476 | if (rot == 3) |
| 1477 | return POS(j, bs - i); /* rotation over 270 degrees */ |
| 1478 | if (rot == 4) |
| 1479 | return POS(j, i); /* flip along diagonal */ |
| 1480 | if (rot == 5) |
| 1481 | return POS(bs - i, j); /* flip */ |
| 1482 | if (rot == 6) |
| 1483 | return POS(bs - j, bs - i); /* flip along diagonal */ |
| 1484 | if (rot == 7) |
| 1485 | return POS(i, bs - j); /* flip */ |
| 1486 | |
| 1487 | return PASS_MOVE; /* unreachable */ |
| 1488 | } |
| 1489 | |
| 1490 | |
| 1491 | /* Returns true if the empty vertex respectively the string at pos1 is |
| 1492 | * adjacent to the empty vertex respectively the string at pos2. |
| 1493 | */ |
| 1494 | int |
| 1495 | are_neighbors(int pos1, int pos2) |
| 1496 | { |
| 1497 | if (board[pos1] == EMPTY) { |
| 1498 | if (board[pos2] == EMPTY) |
| 1499 | return (gg_abs(pos1 - pos2) == NS || gg_abs(pos1 - pos2) == WE); |
| 1500 | else |
| 1501 | return neighbor_of_string(pos1, pos2); |
| 1502 | } |
| 1503 | else { |
| 1504 | if (board[pos2] == EMPTY) |
| 1505 | return neighbor_of_string(pos2, pos1); |
| 1506 | else |
| 1507 | return adjacent_strings(pos1, pos2); |
| 1508 | } |
| 1509 | } |
| 1510 | |
| 1511 | |
| 1512 | /* Count the number of liberties of the string at pos. pos must not be |
| 1513 | * empty. |
| 1514 | */ |
| 1515 | int |
| 1516 | countlib(int str) |
| 1517 | { |
| 1518 | ASSERT1(IS_STONE(board[str]), str); |
| 1519 | |
| 1520 | /* We already know the number of liberties. Just look it up. */ |
| 1521 | return string[string_number[str]].liberties; |
| 1522 | } |
| 1523 | |
| 1524 | |
| 1525 | /* Find the liberties of the string at str. str must not be |
| 1526 | * empty. The locations of up to maxlib liberties are written into |
| 1527 | * libs[]. The full number of liberties is returned. |
| 1528 | * |
| 1529 | * If you want the locations of all liberties, whatever their number, |
| 1530 | * you should pass MAXLIBS as the value for maxlib and allocate space |
| 1531 | * for libs[] accordingly. |
| 1532 | */ |
| 1533 | |
| 1534 | int |
| 1535 | findlib(int str, int maxlib, int *libs) |
| 1536 | { |
| 1537 | int k; |
| 1538 | int liberties; |
| 1539 | int s; |
| 1540 | |
| 1541 | ASSERT1(IS_STONE(board[str]), str); |
| 1542 | ASSERT1(libs != NULL, str); |
| 1543 | |
| 1544 | /* We already have the list of liberties and only need to copy it to |
| 1545 | * libs[]. |
| 1546 | * |
| 1547 | * However, if the string has more than MAX_LIBERTIES liberties the |
| 1548 | * list is truncated and if maxlib is also larger than MAX_LIBERTIES |
| 1549 | * we have to traverse the stones in the string in order to find |
| 1550 | * where the liberties are. |
| 1551 | */ |
| 1552 | s = string_number[str]; |
| 1553 | liberties = string[s].liberties; |
| 1554 | |
| 1555 | if (liberties <= MAX_LIBERTIES || maxlib <= MAX_LIBERTIES) { |
| 1556 | /* The easy case, it suffices to copy liberty locations from the |
| 1557 | * incrementally updated list. |
| 1558 | */ |
| 1559 | for (k = 0; k < maxlib && k < liberties; k++) |
| 1560 | libs[k] = string_libs[s].list[k]; |
| 1561 | } |
| 1562 | else { |
| 1563 | /* The harder case, where we have to traverse the stones in the |
| 1564 | * string. We don't have to check explicitly if we are back to |
| 1565 | * the start of the chain since we will run out of liberties |
| 1566 | * before that happens. |
| 1567 | */ |
| 1568 | int pos; |
| 1569 | liberty_mark++; |
| 1570 | for (k = 0, pos = FIRST_STONE(s); |
| 1571 | k < maxlib && k < liberties; |
| 1572 | pos = NEXT_STONE(pos)) { |
| 1573 | if (UNMARKED_LIBERTY(SOUTH(pos))) { |
| 1574 | libs[k++] = SOUTH(pos); |
| 1575 | MARK_LIBERTY(SOUTH(pos)); |
| 1576 | if (k >= maxlib) |
| 1577 | break; |
| 1578 | } |
| 1579 | |
| 1580 | if (UNMARKED_LIBERTY(WEST(pos))) { |
| 1581 | libs[k++] = WEST(pos); |
| 1582 | MARK_LIBERTY(WEST(pos)); |
| 1583 | if (k >= maxlib) |
| 1584 | break; |
| 1585 | } |
| 1586 | |
| 1587 | if (UNMARKED_LIBERTY(NORTH(pos))) { |
| 1588 | libs[k++] = NORTH(pos); |
| 1589 | MARK_LIBERTY(NORTH(pos)); |
| 1590 | if (k >= maxlib) |
| 1591 | break; |
| 1592 | } |
| 1593 | |
| 1594 | if (UNMARKED_LIBERTY(EAST(pos))) { |
| 1595 | libs[k++] = EAST(pos); |
| 1596 | MARK_LIBERTY(EAST(pos)); |
| 1597 | if (k >= maxlib) |
| 1598 | break; |
| 1599 | } |
| 1600 | } |
| 1601 | } |
| 1602 | |
| 1603 | return liberties; |
| 1604 | } |
| 1605 | |
| 1606 | /* Count the liberties a stone of the given color would get if played |
| 1607 | * at (pos). The location (pos) must be empty. |
| 1608 | * |
| 1609 | * The intent of this function is to be as fast as possible, not |
| 1610 | * necessarily complete. But if it returns a positive value (meaning |
| 1611 | * it has succeeded), the value is guaranteed to be correct. |
| 1612 | * |
| 1613 | * Captures are ignored based on the ignore_capture flag. The function |
| 1614 | * fails if there are more than two neighbor strings of the same |
| 1615 | * color. In this case, the return value is -1. Captures are handled |
| 1616 | * in a very limited way, so if ignore_capture is 0, and a capture is |
| 1617 | * required, it will often return -1. |
| 1618 | * |
| 1619 | * Note well, that it relies on incremental data. |
| 1620 | */ |
| 1621 | |
| 1622 | int |
| 1623 | fastlib(int pos, int color, int ignore_captures) |
| 1624 | { |
| 1625 | int ally1 = -1; |
| 1626 | int ally2 = -1; |
| 1627 | int fast_liberties = 0; |
| 1628 | |
| 1629 | ASSERT1(board[pos] == EMPTY, pos); |
| 1630 | ASSERT1(IS_STONE(color), pos); |
| 1631 | |
| 1632 | /* Find neighboring strings of the same color. If there are more than two of |
| 1633 | * them, we give up (it's too difficult to count their common liberties). |
| 1634 | */ |
| 1635 | if (board[SOUTH(pos)] == color) { |
| 1636 | ally1 = string_number[SOUTH(pos)]; |
| 1637 | |
| 1638 | if (board[WEST(pos)] == color |
| 1639 | && string_number[WEST(pos)] != ally1) { |
| 1640 | ally2 = string_number[WEST(pos)]; |
| 1641 | |
| 1642 | if (board[NORTH(pos)] == color |
| 1643 | && string_number[NORTH(pos)] != ally1 |
| 1644 | && string_number[NORTH(pos)] != ally2) |
| 1645 | return -1; |
| 1646 | } |
| 1647 | else if (board[NORTH(pos)] == color |
| 1648 | && string_number[NORTH(pos)] != ally1) |
| 1649 | ally2 = string_number[NORTH(pos)]; |
| 1650 | |
| 1651 | if (board[EAST(pos)] == color |
| 1652 | && string_number[EAST(pos)] != ally1) { |
| 1653 | if (ally2 < 0) |
| 1654 | ally2 = string_number[EAST(pos)]; |
| 1655 | else if (string_number[EAST(pos)] != ally2) |
| 1656 | return -1; |
| 1657 | } |
| 1658 | } |
| 1659 | else if (board[WEST(pos)] == color) { |
| 1660 | ally1 = string_number[WEST(pos)]; |
| 1661 | |
| 1662 | if (board[NORTH(pos)] == color |
| 1663 | && string_number[NORTH(pos)] != ally1) { |
| 1664 | ally2 = string_number[NORTH(pos)]; |
| 1665 | |
| 1666 | if (board[EAST(pos)] == color |
| 1667 | && string_number[EAST(pos)] != ally1 |
| 1668 | && string_number[EAST(pos)] != ally2) |
| 1669 | return -1; |
| 1670 | } |
| 1671 | else if (board[EAST(pos)] == color |
| 1672 | && string_number[EAST(pos)] != ally1) |
| 1673 | ally2 = string_number[EAST(pos)]; |
| 1674 | } |
| 1675 | else if (board[NORTH(pos)] == color) { |
| 1676 | ally1 = string_number[NORTH(pos)]; |
| 1677 | |
| 1678 | if (board[EAST(pos)] == color |
| 1679 | && string_number[EAST(pos)] != ally1) |
| 1680 | ally2 = string_number[EAST(pos)]; |
| 1681 | } |
| 1682 | else if (board[EAST(pos)] == color) |
| 1683 | ally1 = string_number[EAST(pos)]; |
| 1684 | |
| 1685 | /* If we are to ignore captures, the things are very easy. */ |
| 1686 | if (ignore_captures) { |
| 1687 | if (ally1 < 0) { /* No allies */ |
| 1688 | if (LIBERTY(SOUTH(pos))) |
| 1689 | fast_liberties++; |
| 1690 | if (LIBERTY(WEST(pos))) |
| 1691 | fast_liberties++; |
| 1692 | if (LIBERTY(NORTH(pos))) |
| 1693 | fast_liberties++; |
| 1694 | if (LIBERTY(EAST(pos))) |
| 1695 | fast_liberties++; |
| 1696 | } |
| 1697 | else if (ally2 < 0) { /* One ally */ |
| 1698 | if (LIBERTY(SOUTH(pos)) |
| 1699 | && !NON_SOUTH_NEIGHBOR_OF_STRING(SOUTH(pos), ally1, color)) |
| 1700 | fast_liberties++; |
| 1701 | if (LIBERTY(WEST(pos)) |
| 1702 | && !NON_WEST_NEIGHBOR_OF_STRING(WEST(pos), ally1, color)) |
| 1703 | fast_liberties++; |
| 1704 | if (LIBERTY(NORTH(pos)) |
| 1705 | && !NON_NORTH_NEIGHBOR_OF_STRING(NORTH(pos), ally1, color)) |
| 1706 | fast_liberties++; |
| 1707 | if (LIBERTY(EAST(pos)) |
| 1708 | && !NON_EAST_NEIGHBOR_OF_STRING(EAST(pos), ally1, color)) |
| 1709 | fast_liberties++; |
| 1710 | |
| 1711 | fast_liberties += string[ally1].liberties - 1; |
| 1712 | } |
| 1713 | else { /* Two allies */ |
| 1714 | if (LIBERTY(SOUTH(pos)) |
| 1715 | && !NON_SOUTH_NEIGHBOR_OF_STRING(SOUTH(pos), ally1, color) |
| 1716 | && !NON_SOUTH_NEIGHBOR_OF_STRING(SOUTH(pos), ally2, color)) |
| 1717 | fast_liberties++; |
| 1718 | if (LIBERTY(WEST(pos)) |
| 1719 | && !NON_WEST_NEIGHBOR_OF_STRING(WEST(pos), ally1, color) |
| 1720 | && !NON_WEST_NEIGHBOR_OF_STRING(WEST(pos), ally2, color)) |
| 1721 | fast_liberties++; |
| 1722 | if (LIBERTY(NORTH(pos)) |
| 1723 | && !NON_NORTH_NEIGHBOR_OF_STRING(NORTH(pos), ally1, color) |
| 1724 | && !NON_NORTH_NEIGHBOR_OF_STRING(NORTH(pos), ally2, color)) |
| 1725 | fast_liberties++; |
| 1726 | if (LIBERTY(EAST(pos)) |
| 1727 | && !NON_EAST_NEIGHBOR_OF_STRING(EAST(pos), ally1, color) |
| 1728 | && !NON_EAST_NEIGHBOR_OF_STRING(EAST(pos), ally2, color)) |
| 1729 | fast_liberties++; |
| 1730 | |
| 1731 | fast_liberties += string[ally1].liberties + string[ally2].liberties |
| 1732 | - count_common_libs(string[ally1].origin, string[ally2].origin) - 1; |
| 1733 | } |
| 1734 | } |
| 1735 | /* We are to take captures into account. This case is much more rare, so |
| 1736 | * it is not optimized much. |
| 1737 | */ |
| 1738 | else { |
| 1739 | int k; |
| 1740 | |
| 1741 | for (k = 0; k < 4; k++) { |
| 1742 | int neighbor = pos + delta[k]; |
| 1743 | |
| 1744 | if (LIBERTY(neighbor) |
| 1745 | && (ally1 < 0 || !NEIGHBOR_OF_STRING(neighbor, ally1, color)) |
| 1746 | && (ally2 < 0 || !NEIGHBOR_OF_STRING(neighbor, ally2, color))) |
| 1747 | fast_liberties++; |
| 1748 | else if (board[neighbor] == OTHER_COLOR(color) /* A capture */ |
| 1749 | && LIBERTIES(neighbor) == 1) { |
| 1750 | int neighbor_size = COUNTSTONES(neighbor); |
| 1751 | |
| 1752 | if (neighbor_size == 1 || (neighbor_size == 2 && ally1 < 0)) |
| 1753 | fast_liberties++; |
| 1754 | else |
| 1755 | return -1; |
| 1756 | } |
| 1757 | } |
| 1758 | |
| 1759 | if (ally1 >= 0) { |
| 1760 | fast_liberties += string[ally1].liberties - 1; |
| 1761 | if (ally2 >= 0) |
| 1762 | fast_liberties += string[ally2].liberties |
| 1763 | - count_common_libs(string[ally1].origin, string[ally2].origin); |
| 1764 | } |
| 1765 | } |
| 1766 | |
| 1767 | return fast_liberties; |
| 1768 | } |
| 1769 | |
| 1770 | |
| 1771 | /* Effectively true unless we store full position in hash. */ |
| 1772 | #define USE_BOARD_CACHES (NUM_HASHVALUES <= 4) |
| 1773 | |
| 1774 | struct board_cache_entry { |
| 1775 | int threshold; |
| 1776 | int liberties; |
| 1777 | Hash_data position_hash; |
| 1778 | }; |
| 1779 | |
| 1780 | |
| 1781 | /* approxlib() cache. */ |
| 1782 | static struct board_cache_entry approxlib_cache[BOARDMAX][2]; |
| 1783 | |
| 1784 | |
| 1785 | /* Clears approxlib() cache. This function should be called only once |
| 1786 | * during engine initialization. Sets thresholds to zero. |
| 1787 | */ |
| 1788 | void |
| 1789 | clear_approxlib_cache(void) |
| 1790 | { |
| 1791 | int pos; |
| 1792 | |
| 1793 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 1794 | approxlib_cache[pos][0].threshold = 0; |
| 1795 | approxlib_cache[pos][1].threshold = 0; |
| 1796 | } |
| 1797 | } |
| 1798 | |
| 1799 | |
| 1800 | /* Find the liberties a stone of the given color would get if played |
| 1801 | * at (pos), ignoring possible captures of opponent stones. (pos) |
| 1802 | * must be empty. If libs != NULL, the locations of up to maxlib |
| 1803 | * liberties are written into libs[]. The counting of liberties may |
| 1804 | * or may not be halted when maxlib is reached. The number of liberties |
| 1805 | * found is returned. |
| 1806 | * |
| 1807 | * If you want the number or the locations of all liberties, however |
| 1808 | * many they are, you should pass MAXLIBS as the value for maxlib and |
| 1809 | * allocate space for libs[] accordingly. |
| 1810 | */ |
| 1811 | int |
| 1812 | approxlib(int pos, int color, int maxlib, int *libs) |
| 1813 | { |
| 1814 | int liberties; |
| 1815 | |
| 1816 | #ifdef USE_BOARD_CACHES |
| 1817 | |
| 1818 | struct board_cache_entry *entry = &approxlib_cache[pos][color - 1]; |
| 1819 | |
| 1820 | ASSERT1(board[pos] == EMPTY, pos); |
| 1821 | ASSERT1(IS_STONE(color), pos); |
| 1822 | |
| 1823 | if (!libs) { |
| 1824 | /* First see if this result is cached. */ |
| 1825 | if (hashdata_is_equal(board_hash, entry->position_hash) |
| 1826 | && maxlib <= entry->threshold) { |
| 1827 | return entry->liberties; |
| 1828 | } |
| 1829 | |
| 1830 | liberties = fastlib(pos, color, 1); |
| 1831 | if (liberties >= 0) { |
| 1832 | /* Since fastlib() always returns precise result and doesn't take |
| 1833 | * `maxlib' into account, we set threshold to MAXLIBS so that this |
| 1834 | * result is used regardless of any `maxlib' passed. |
| 1835 | */ |
| 1836 | entry->threshold = MAXLIBS; |
| 1837 | entry->liberties = liberties; |
| 1838 | entry->position_hash = board_hash; |
| 1839 | |
| 1840 | return liberties; |
| 1841 | } |
| 1842 | } |
| 1843 | |
| 1844 | /* We initialize the cache entry threshold to `maxlib'. If do_approxlib() |
| 1845 | * or slow_approxlib() finds all the liberties (that is, they don't use |
| 1846 | * `maxlib' value for an early return), they will set threshold to |
| 1847 | * MAXLIBS themselves. |
| 1848 | */ |
| 1849 | entry->threshold = maxlib; |
| 1850 | |
| 1851 | if (maxlib <= MAX_LIBERTIES) |
| 1852 | liberties = do_approxlib(pos, color, maxlib, libs); |
| 1853 | else |
| 1854 | liberties = slow_approxlib(pos, color, maxlib, libs); |
| 1855 | |
| 1856 | entry->liberties = liberties; |
| 1857 | entry->position_hash = board_hash; |
| 1858 | |
| 1859 | #else /* not USE_BOARD_CACHES */ |
| 1860 | |
| 1861 | ASSERT1(board[pos] == EMPTY, pos); |
| 1862 | ASSERT1(IS_STONE(color), pos); |
| 1863 | |
| 1864 | if (!libs) { |
| 1865 | liberties = fastlib(pos, color, 1); |
| 1866 | if (liberties >= 0) |
| 1867 | return liberties; |
| 1868 | } |
| 1869 | |
| 1870 | if (maxlib <= MAX_LIBERTIES) |
| 1871 | liberties = do_approxlib(pos, color, maxlib, libs); |
| 1872 | else |
| 1873 | liberties = slow_approxlib(pos, color, maxlib, libs); |
| 1874 | |
| 1875 | #endif /* not USE_BOARD_CACHES */ |
| 1876 | |
| 1877 | return liberties; |
| 1878 | } |
| 1879 | |
| 1880 | |
| 1881 | /* Does the real work of approxlib(). */ |
| 1882 | static int |
| 1883 | do_approxlib(int pos, int color, int maxlib, int *libs) |
| 1884 | { |
| 1885 | int k; |
| 1886 | int liberties = 0; |
| 1887 | |
| 1888 | /* Look for empty neighbors and the liberties of the adjacent |
| 1889 | * strings of the given color. The algorithm below won't work |
| 1890 | * correctly if any of the adjacent strings have more than |
| 1891 | * MAX_LIBERTIES liberties AND maxlib is larger than MAX_LIBERTIES. |
| 1892 | * therefore approxlib() calls more robust slow_approxlib() if |
| 1893 | * this might be the case. |
| 1894 | */ |
| 1895 | |
| 1896 | /* Start by marking pos itself so it isn't counted among its own |
| 1897 | * liberties. |
| 1898 | */ |
| 1899 | liberty_mark++; |
| 1900 | MARK_LIBERTY(pos); |
| 1901 | |
| 1902 | if (UNMARKED_LIBERTY(SOUTH(pos))) { |
| 1903 | if (libs != NULL) |
| 1904 | libs[liberties] = SOUTH(pos); |
| 1905 | liberties++; |
| 1906 | /* Stop counting if we reach maxlib. */ |
| 1907 | if (liberties >= maxlib) |
| 1908 | return liberties; |
| 1909 | MARK_LIBERTY(SOUTH(pos)); |
| 1910 | } |
| 1911 | else if (board[SOUTH(pos)] == color) { |
| 1912 | int s = string_number[SOUTH(pos)]; |
| 1913 | for (k = 0; k < string[s].liberties; k++) { |
| 1914 | int lib = string_libs[s].list[k]; |
| 1915 | if (UNMARKED_LIBERTY(lib)) { |
| 1916 | if (libs != NULL) |
| 1917 | libs[liberties] = lib; |
| 1918 | liberties++; |
| 1919 | if (liberties >= maxlib) |
| 1920 | return liberties; |
| 1921 | MARK_LIBERTY(lib); |
| 1922 | } |
| 1923 | } |
| 1924 | } |
| 1925 | |
| 1926 | if (UNMARKED_LIBERTY(WEST(pos))) { |
| 1927 | if (libs != NULL) |
| 1928 | libs[liberties] = WEST(pos); |
| 1929 | liberties++; |
| 1930 | /* Stop counting if we reach maxlib. */ |
| 1931 | if (liberties >= maxlib) |
| 1932 | return liberties; |
| 1933 | MARK_LIBERTY(WEST(pos)); |
| 1934 | } |
| 1935 | else if (board[WEST(pos)] == color) { |
| 1936 | int s = string_number[WEST(pos)]; |
| 1937 | for (k = 0; k < string[s].liberties; k++) { |
| 1938 | int lib = string_libs[s].list[k]; |
| 1939 | if (UNMARKED_LIBERTY(lib)) { |
| 1940 | if (libs != NULL) |
| 1941 | libs[liberties] = lib; |
| 1942 | liberties++; |
| 1943 | if (liberties >= maxlib) |
| 1944 | return liberties; |
| 1945 | MARK_LIBERTY(lib); |
| 1946 | } |
| 1947 | } |
| 1948 | } |
| 1949 | |
| 1950 | if (UNMARKED_LIBERTY(NORTH(pos))) { |
| 1951 | if (libs != NULL) |
| 1952 | libs[liberties] = NORTH(pos); |
| 1953 | liberties++; |
| 1954 | /* Stop counting if we reach maxlib. */ |
| 1955 | if (liberties >= maxlib) |
| 1956 | return liberties; |
| 1957 | MARK_LIBERTY(NORTH(pos)); |
| 1958 | } |
| 1959 | else if (board[NORTH(pos)] == color) { |
| 1960 | int s = string_number[NORTH(pos)]; |
| 1961 | for (k = 0; k < string[s].liberties; k++) { |
| 1962 | int lib = string_libs[s].list[k]; |
| 1963 | if (UNMARKED_LIBERTY(lib)) { |
| 1964 | if (libs != NULL) |
| 1965 | libs[liberties] = lib; |
| 1966 | liberties++; |
| 1967 | if (liberties >= maxlib) |
| 1968 | return liberties; |
| 1969 | MARK_LIBERTY(lib); |
| 1970 | } |
| 1971 | } |
| 1972 | } |
| 1973 | |
| 1974 | if (UNMARKED_LIBERTY(EAST(pos))) { |
| 1975 | if (libs != NULL) |
| 1976 | libs[liberties] = EAST(pos); |
| 1977 | liberties++; |
| 1978 | /* Unneeded since we're about to leave. */ |
| 1979 | #if 0 |
| 1980 | if (liberties >= maxlib) |
| 1981 | return liberties; |
| 1982 | MARK_LIBERTY(EAST(pos)); |
| 1983 | #endif |
| 1984 | } |
| 1985 | else if (board[EAST(pos)] == color) { |
| 1986 | int s = string_number[EAST(pos)]; |
| 1987 | for (k = 0; k < string[s].liberties; k++) { |
| 1988 | int lib = string_libs[s].list[k]; |
| 1989 | if (UNMARKED_LIBERTY(lib)) { |
| 1990 | if (libs != NULL) |
| 1991 | libs[liberties] = lib; |
| 1992 | liberties++; |
| 1993 | if (liberties >= maxlib) |
| 1994 | return liberties; |
| 1995 | MARK_LIBERTY(lib); |
| 1996 | } |
| 1997 | } |
| 1998 | } |
| 1999 | |
| 2000 | #if USE_BOARD_CACHES |
| 2001 | /* If we reach here, then we have counted _all_ the liberties, so |
| 2002 | * we set threshold to MAXLIBS (the result is the same regardless |
| 2003 | * of `maxlib' value). |
| 2004 | */ |
| 2005 | if (!libs) |
| 2006 | approxlib_cache[pos][color - 1].threshold = MAXLIBS; |
| 2007 | #endif |
| 2008 | return liberties; |
| 2009 | } |
| 2010 | |
| 2011 | |
| 2012 | /* Find the liberties a move of the given color at pos would have, |
| 2013 | * excluding possible captures, by traversing all adjacent friendly |
| 2014 | * strings. This is a fallback used by approxlib() when a faster |
| 2015 | * algorithm can't be used. |
| 2016 | */ |
| 2017 | static int |
| 2018 | slow_approxlib(int pos, int color, int maxlib, int *libs) |
| 2019 | { |
| 2020 | int k; |
| 2021 | int liberties = 0; |
| 2022 | |
| 2023 | liberty_mark++; |
| 2024 | MARK_LIBERTY(pos); |
| 2025 | string_mark++; |
| 2026 | for (k = 0; k < 4; k++) { |
| 2027 | int d = delta[k]; |
| 2028 | if (UNMARKED_LIBERTY(pos + d)) { |
| 2029 | if (libs) |
| 2030 | libs[liberties] = pos + d; |
| 2031 | liberties++; |
| 2032 | if (liberties == maxlib) |
| 2033 | return liberties; |
| 2034 | MARK_LIBERTY(pos + d); |
| 2035 | } |
| 2036 | else if (board[pos + d] == color |
| 2037 | && UNMARKED_STRING(pos + d)) { |
| 2038 | int s = string_number[pos + d]; |
| 2039 | int pos2; |
| 2040 | pos2 = FIRST_STONE(s); |
| 2041 | do { |
| 2042 | int l; |
| 2043 | for (l = 0; l < 4; l++) { |
| 2044 | int d2 = delta[l]; |
| 2045 | if (UNMARKED_LIBERTY(pos2 + d2)) { |
| 2046 | if (libs) |
| 2047 | libs[liberties] = pos2 + d2; |
| 2048 | liberties++; |
| 2049 | if (liberties == maxlib) |
| 2050 | return liberties; |
| 2051 | MARK_LIBERTY(pos2 + d2); |
| 2052 | } |
| 2053 | } |
| 2054 | |
| 2055 | pos2 = NEXT_STONE(pos2); |
| 2056 | } while (!BACK_TO_FIRST_STONE(s, pos2)); |
| 2057 | MARK_STRING(pos + d); |
| 2058 | } |
| 2059 | } |
| 2060 | |
| 2061 | #if USE_BOARD_CACHES |
| 2062 | /* If we reach here, then we have counted _all_ the liberties, so |
| 2063 | * we set threshold to MAXLIBS (the result is the same regardless |
| 2064 | * of `maxlib' value). |
| 2065 | */ |
| 2066 | if (!libs) |
| 2067 | approxlib_cache[pos][color - 1].threshold = MAXLIBS; |
| 2068 | #endif |
| 2069 | return liberties; |
| 2070 | } |
| 2071 | |
| 2072 | |
| 2073 | /* accuratelib() cache. */ |
| 2074 | static struct board_cache_entry accuratelib_cache[BOARDMAX][2]; |
| 2075 | |
| 2076 | |
| 2077 | /* Clears accuratelib() cache. This function should be called only once |
| 2078 | * during engine initialization. Sets thresholds to zero. |
| 2079 | */ |
| 2080 | void |
| 2081 | clear_accuratelib_cache(void) |
| 2082 | { |
| 2083 | int pos; |
| 2084 | |
| 2085 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 2086 | accuratelib_cache[pos][0].threshold = 0; |
| 2087 | accuratelib_cache[pos][1].threshold = 0; |
| 2088 | } |
| 2089 | } |
| 2090 | |
| 2091 | |
| 2092 | /* Find the liberties a stone of the given color would get if played |
| 2093 | * at (pos). This function takes into consideration all captures. Its |
| 2094 | * return value is exact in that sense it counts all the liberties, |
| 2095 | * unless (maxlib) allows it to stop earlier. (pos) must be empty. If |
| 2096 | * libs != NULL, the locations of up to maxlib liberties are written |
| 2097 | * into libs[]. The counting of liberties may or may not be halted |
| 2098 | * when maxlib is reached. The number of found liberties is returned. |
| 2099 | * |
| 2100 | * This function guarantees that liberties which are not results of |
| 2101 | * captures come first in libs[] array. To find whether all the |
| 2102 | * liberties starting from a given one are results of captures, one |
| 2103 | * may use if (board[libs[k]] != EMPTY) construction. |
| 2104 | * |
| 2105 | * If you want the number or the locations of all liberties, however |
| 2106 | * many they are, you should pass MAXLIBS as the value for maxlib and |
| 2107 | * allocate space for libs[] accordingly. |
| 2108 | */ |
| 2109 | int |
| 2110 | accuratelib(int pos, int color, int maxlib, int *libs) |
| 2111 | { |
| 2112 | int liberties; |
| 2113 | |
| 2114 | #ifdef USE_BOARD_CACHES |
| 2115 | |
| 2116 | struct board_cache_entry *entry = &accuratelib_cache[pos][color - 1]; |
| 2117 | |
| 2118 | ASSERT1(board[pos] == EMPTY, pos); |
| 2119 | ASSERT1(IS_STONE(color), pos); |
| 2120 | |
| 2121 | if (!libs) { |
| 2122 | /* First see if this result is cached. */ |
| 2123 | if (hashdata_is_equal(board_hash, entry->position_hash) |
| 2124 | && maxlib <= entry->threshold) { |
| 2125 | return entry->liberties; |
| 2126 | } |
| 2127 | |
| 2128 | liberties = fastlib(pos, color, 0); |
| 2129 | if (liberties >= 0) { |
| 2130 | /* Since fastlib() always returns precise result and doesn't take |
| 2131 | * `maxlib' into account, we set threshold to MAXLIBS so that this |
| 2132 | * result is used regardless of any `maxlib' passed. |
| 2133 | */ |
| 2134 | entry->threshold = MAXLIBS; |
| 2135 | entry->liberties = liberties; |
| 2136 | entry->position_hash = board_hash; |
| 2137 | |
| 2138 | return liberties; |
| 2139 | } |
| 2140 | } |
| 2141 | |
| 2142 | liberties = do_accuratelib(pos, color, maxlib, libs); |
| 2143 | |
| 2144 | /* If accuratelib() found less than `maxlib' liberties, then its |
| 2145 | * result is certainly independent of `maxlib' and we set threshold |
| 2146 | * to MAXLIBS. |
| 2147 | */ |
| 2148 | entry->threshold = liberties < maxlib ? MAXLIBS : maxlib; |
| 2149 | entry->liberties = liberties; |
| 2150 | entry->position_hash = board_hash; |
| 2151 | |
| 2152 | #else /* not USE_BOARD_CACHES */ |
| 2153 | |
| 2154 | ASSERT1(board[pos] == EMPTY, pos); |
| 2155 | ASSERT1(IS_STONE(color), pos); |
| 2156 | |
| 2157 | if (!libs) { |
| 2158 | liberties = fastlib(pos, color, 0); |
| 2159 | if (liberties >= 0) |
| 2160 | return liberties; |
| 2161 | } |
| 2162 | |
| 2163 | liberties = do_accuratelib(pos, color, maxlib, libs); |
| 2164 | |
| 2165 | #endif /* not USE_BOARD_CACHES */ |
| 2166 | |
| 2167 | return liberties; |
| 2168 | } |
| 2169 | |
| 2170 | |
| 2171 | /* Does the real work of accuratelib(). */ |
| 2172 | static int |
| 2173 | do_accuratelib(int pos, int color, int maxlib, int *libs) |
| 2174 | { |
| 2175 | int k, l; |
| 2176 | int liberties = 0; |
| 2177 | int lib; |
| 2178 | int captured[4]; |
| 2179 | int captures = 0; |
| 2180 | |
| 2181 | string_mark++; |
| 2182 | liberty_mark++; |
| 2183 | MARK_LIBERTY(pos); |
| 2184 | |
| 2185 | for (k = 0; k < 4; k++) { |
| 2186 | int pos2 = pos + delta[k]; |
| 2187 | if (UNMARKED_LIBERTY(pos2)) { |
| 2188 | /* A trivial liberty */ |
| 2189 | if (libs) |
| 2190 | libs[liberties] = pos2; |
| 2191 | liberties++; |
| 2192 | if (liberties >= maxlib) |
| 2193 | return liberties; |
| 2194 | |
| 2195 | MARK_LIBERTY(pos2); |
| 2196 | } |
| 2197 | else if (UNMARKED_COLOR_STRING(pos2, color)) { |
| 2198 | /* An own neighbor string */ |
| 2199 | struct string_data *s = &string[string_number[pos2]]; |
| 2200 | struct string_liberties_data *sl = &string_libs[string_number[pos2]]; |
| 2201 | |
| 2202 | if (s->liberties <= MAX_LIBERTIES || maxlib <= MAX_LIBERTIES - 1) { |
| 2203 | /* The easy case - we already have all (necessary) liberties of |
| 2204 | * the string listed |
| 2205 | */ |
| 2206 | for (l = 0; l < s->liberties; l++) { |
| 2207 | lib = sl->list[l]; |
| 2208 | if (UNMARKED_LIBERTY(lib)) { |
| 2209 | if (libs) |
| 2210 | libs[liberties] = lib; |
| 2211 | liberties++; |
| 2212 | if (liberties >= maxlib) |
| 2213 | return liberties; |
| 2214 | |
| 2215 | MARK_LIBERTY(lib); |
| 2216 | } |
| 2217 | } |
| 2218 | } |
| 2219 | else { |
| 2220 | /* The harder case - we need to find all the liberties of the |
| 2221 | * string by traversing its stones. We stop as soon as we have |
| 2222 | * traversed all the stones or have reached maxlib. Unfortunately, |
| 2223 | * we cannot use the trick from findlib() since some of the |
| 2224 | * liberties may already have been marked. |
| 2225 | */ |
| 2226 | int stone = pos2; |
| 2227 | do { |
| 2228 | if (UNMARKED_LIBERTY(SOUTH(stone))) { |
| 2229 | if (libs) |
| 2230 | libs[liberties] = SOUTH(stone); |
| 2231 | liberties++; |
| 2232 | if (liberties >= maxlib) |
| 2233 | return liberties; |
| 2234 | |
| 2235 | MARK_LIBERTY(SOUTH(stone)); |
| 2236 | } |
| 2237 | |
| 2238 | if (UNMARKED_LIBERTY(WEST(stone))) { |
| 2239 | if (libs) |
| 2240 | libs[liberties] = WEST(stone); |
| 2241 | liberties++; |
| 2242 | if (liberties >= maxlib) |
| 2243 | return liberties; |
| 2244 | |
| 2245 | MARK_LIBERTY(WEST(stone)); |
| 2246 | } |
| 2247 | |
| 2248 | if (UNMARKED_LIBERTY(NORTH(stone))) { |
| 2249 | if (libs) |
| 2250 | libs[liberties] = NORTH(stone); |
| 2251 | liberties++; |
| 2252 | if (liberties >= maxlib) |
| 2253 | return liberties; |
| 2254 | |
| 2255 | MARK_LIBERTY(NORTH(stone)); |
| 2256 | } |
| 2257 | |
| 2258 | if (UNMARKED_LIBERTY(EAST(stone))) { |
| 2259 | if (libs) |
| 2260 | libs[liberties] = EAST(stone); |
| 2261 | liberties++; |
| 2262 | if (liberties >= maxlib) |
| 2263 | return liberties; |
| 2264 | |
| 2265 | MARK_LIBERTY(EAST(stone)); |
| 2266 | } |
| 2267 | |
| 2268 | stone = NEXT_STONE(stone); |
| 2269 | } while (stone != pos2); |
| 2270 | } |
| 2271 | |
| 2272 | MARK_STRING(pos2); |
| 2273 | } |
| 2274 | else if (board[pos2] == OTHER_COLOR(color) |
| 2275 | && string[string_number[pos2]].liberties == 1) { |
| 2276 | /* A capture. */ |
| 2277 | captured[captures++] = pos2; |
| 2278 | } |
| 2279 | } |
| 2280 | |
| 2281 | /* Now we look at all the captures found in the previous step */ |
| 2282 | for (k = 0; k < captures; k++) { |
| 2283 | lib = captured[k]; |
| 2284 | |
| 2285 | /* Add the stone adjacent to (pos) to the list of liberties if |
| 2286 | * it is not also adjacent to an own marked string (otherwise, |
| 2287 | * it will be added later). |
| 2288 | */ |
| 2289 | if (!MARKED_COLOR_STRING(SOUTH(lib), color) |
| 2290 | && !MARKED_COLOR_STRING(WEST(lib), color) |
| 2291 | && !MARKED_COLOR_STRING(NORTH(lib), color) |
| 2292 | && !MARKED_COLOR_STRING(EAST(lib), color)) { |
| 2293 | if (libs) |
| 2294 | libs[liberties] = lib; |
| 2295 | liberties++; |
| 2296 | if (liberties >= maxlib) |
| 2297 | return liberties; |
| 2298 | } |
| 2299 | |
| 2300 | /* Check if we already know of this capture. */ |
| 2301 | for (l = 0; l < k; l++) |
| 2302 | if (string_number[captured[l]] == string_number[lib]) |
| 2303 | break; |
| 2304 | |
| 2305 | if (l == k) { |
| 2306 | /* Traverse all the stones of the capture and add to the list |
| 2307 | * of liberties those, which are adjacent to at least one own |
| 2308 | * marked string. |
| 2309 | */ |
| 2310 | do { |
| 2311 | if (MARKED_COLOR_STRING(SOUTH(lib), color) |
| 2312 | || MARKED_COLOR_STRING(WEST(lib), color) |
| 2313 | || MARKED_COLOR_STRING(NORTH(lib), color) |
| 2314 | || MARKED_COLOR_STRING(EAST(lib), color)) { |
| 2315 | if (libs) |
| 2316 | libs[liberties] = lib; |
| 2317 | liberties++; |
| 2318 | if (liberties >= maxlib) |
| 2319 | return liberties; |
| 2320 | } |
| 2321 | |
| 2322 | lib = NEXT_STONE(lib); |
| 2323 | } while (lib != captured[k]); |
| 2324 | } |
| 2325 | } |
| 2326 | |
| 2327 | return liberties; |
| 2328 | } |
| 2329 | |
| 2330 | |
| 2331 | /* Find the number of common liberties of the two strings at str1 and str2. |
| 2332 | */ |
| 2333 | |
| 2334 | int |
| 2335 | count_common_libs(int str1, int str2) |
| 2336 | { |
| 2337 | int all_libs1[MAXLIBS], *libs1; |
| 2338 | int liberties1, liberties2; |
| 2339 | int commonlibs = 0; |
| 2340 | int k, n, tmp; |
| 2341 | |
| 2342 | ASSERT_ON_BOARD1(str1); |
| 2343 | ASSERT_ON_BOARD1(str2); |
| 2344 | ASSERT1(IS_STONE(board[str1]), str1); |
| 2345 | ASSERT1(IS_STONE(board[str2]), str2); |
| 2346 | |
| 2347 | n = string_number[str1]; |
| 2348 | liberties1 = string[n].liberties; |
| 2349 | |
| 2350 | if (liberties1 > string[string_number[str2]].liberties) { |
| 2351 | n = string_number[str2]; |
| 2352 | liberties1 = string[n].liberties; |
| 2353 | tmp = str1; |
| 2354 | str1 = str2; |
| 2355 | str2 = tmp; |
| 2356 | } |
| 2357 | |
| 2358 | if (liberties1 <= MAX_LIBERTIES) { |
| 2359 | /* Speed optimization: don't copy liberties with findlib */ |
| 2360 | libs1 = string_libs[n].list; |
| 2361 | n = string_number[str2]; |
| 2362 | liberties2 = string[n].liberties; |
| 2363 | |
| 2364 | if (liberties2 <= MAX_LIBERTIES) { |
| 2365 | /* Speed optimization: NEIGHBOR_OF_STRING is quite expensive */ |
| 2366 | liberty_mark++; |
| 2367 | |
| 2368 | for (k = 0; k < liberties1; k++) |
| 2369 | MARK_LIBERTY(libs1[k]); |
| 2370 | |
| 2371 | libs1 = string_libs[n].list; |
| 2372 | for (k = 0; k < liberties2; k++) |
| 2373 | if (!UNMARKED_LIBERTY(libs1[k])) |
| 2374 | commonlibs++; |
| 2375 | |
| 2376 | return commonlibs; |
| 2377 | } |
| 2378 | } |
| 2379 | else { |
| 2380 | findlib(str1, MAXLIBS, all_libs1); |
| 2381 | libs1 = all_libs1; |
| 2382 | } |
| 2383 | |
| 2384 | for (k = 0; k < liberties1; k++) |
| 2385 | if (NEIGHBOR_OF_STRING(libs1[k], string_number[str2], board[str2])) |
| 2386 | commonlibs++; |
| 2387 | |
| 2388 | return commonlibs; |
| 2389 | } |
| 2390 | |
| 2391 | |
| 2392 | /* Find the common liberties of the two strings at str1 and str2. The |
| 2393 | * locations of up to maxlib common liberties are written into libs[]. |
| 2394 | * The full number of common liberties is returned. |
| 2395 | * |
| 2396 | * If you want the locations of all common liberties, whatever their |
| 2397 | * number, you should pass MAXLIBS as the value for maxlib and |
| 2398 | * allocate space for libs[] accordingly. |
| 2399 | */ |
| 2400 | |
| 2401 | int |
| 2402 | find_common_libs(int str1, int str2, int maxlib, int *libs) |
| 2403 | { |
| 2404 | int all_libs1[MAXLIBS], *libs1; |
| 2405 | int liberties1, liberties2; |
| 2406 | int commonlibs = 0; |
| 2407 | int k, n, tmp; |
| 2408 | |
| 2409 | ASSERT_ON_BOARD1(str1); |
| 2410 | ASSERT_ON_BOARD1(str2); |
| 2411 | ASSERT1(IS_STONE(board[str1]), str1); |
| 2412 | ASSERT1(IS_STONE(board[str2]), str2); |
| 2413 | ASSERT1(libs != NULL, str1); |
| 2414 | |
| 2415 | n = string_number[str1]; |
| 2416 | liberties1 = string[n].liberties; |
| 2417 | |
| 2418 | if (liberties1 > string[string_number[str2]].liberties) { |
| 2419 | n = string_number[str2]; |
| 2420 | liberties1 = string[n].liberties; |
| 2421 | tmp = str1; |
| 2422 | str1 = str2; |
| 2423 | str2 = tmp; |
| 2424 | } |
| 2425 | |
| 2426 | if (liberties1 <= MAX_LIBERTIES) { |
| 2427 | /* Speed optimization: don't copy liberties with findlib */ |
| 2428 | libs1 = string_libs[n].list; |
| 2429 | n = string_number[str2]; |
| 2430 | liberties2 = string[n].liberties; |
| 2431 | |
| 2432 | if (liberties2 <= MAX_LIBERTIES) { |
| 2433 | /* Speed optimization: NEIGHBOR_OF_STRING is quite expensive */ |
| 2434 | liberty_mark++; |
| 2435 | |
| 2436 | for (k = 0; k < liberties1; k++) |
| 2437 | MARK_LIBERTY(libs1[k]); |
| 2438 | |
| 2439 | libs1 = string_libs[n].list; |
| 2440 | for (k = 0; k < liberties2; k++) |
| 2441 | if (!UNMARKED_LIBERTY(libs1[k])) { |
| 2442 | if (commonlibs < maxlib) |
| 2443 | libs[commonlibs] = libs1[k]; |
| 2444 | commonlibs++; |
| 2445 | } |
| 2446 | |
| 2447 | return commonlibs; |
| 2448 | } |
| 2449 | } |
| 2450 | else { |
| 2451 | findlib(str1, MAXLIBS, all_libs1); |
| 2452 | libs1 = all_libs1; |
| 2453 | } |
| 2454 | |
| 2455 | for (k = 0; k < liberties1; k++) |
| 2456 | if (NEIGHBOR_OF_STRING(libs1[k], string_number[str2], board[str2])) { |
| 2457 | if (commonlibs < maxlib) |
| 2458 | libs[commonlibs] = libs1[k]; |
| 2459 | commonlibs++; |
| 2460 | } |
| 2461 | |
| 2462 | return commonlibs; |
| 2463 | } |
| 2464 | |
| 2465 | |
| 2466 | /* Determine whether two strings have at least one common liberty. |
| 2467 | * If they do and lib != NULL, one common liberty is returned in *lib. |
| 2468 | */ |
| 2469 | int |
| 2470 | have_common_lib(int str1, int str2, int *lib) |
| 2471 | { |
| 2472 | int all_libs1[MAXLIBS], *libs1; |
| 2473 | int liberties1; |
| 2474 | int k, n, tmp; |
| 2475 | |
| 2476 | ASSERT_ON_BOARD1(str1); |
| 2477 | ASSERT_ON_BOARD1(str2); |
| 2478 | ASSERT1(IS_STONE(board[str1]), str1); |
| 2479 | ASSERT1(IS_STONE(board[str2]), str2); |
| 2480 | |
| 2481 | n = string_number[str1]; |
| 2482 | liberties1 = string[n].liberties; |
| 2483 | |
| 2484 | if (liberties1 > string[string_number[str2]].liberties) { |
| 2485 | n = string_number[str2]; |
| 2486 | liberties1 = string[n].liberties; |
| 2487 | tmp = str1; |
| 2488 | str1 = str2; |
| 2489 | str2 = tmp; |
| 2490 | } |
| 2491 | |
| 2492 | if (liberties1 <= MAX_LIBERTIES) |
| 2493 | /* Speed optimization: don't copy liberties with findlib */ |
| 2494 | libs1 = string_libs[n].list; |
| 2495 | else { |
| 2496 | findlib(str1, MAXLIBS, all_libs1); |
| 2497 | libs1 = all_libs1; |
| 2498 | } |
| 2499 | |
| 2500 | for (k = 0; k < liberties1; k++) { |
| 2501 | if (NEIGHBOR_OF_STRING(libs1[k], string_number[str2], board[str2])) { |
| 2502 | if (lib) |
| 2503 | *lib = libs1[k]; |
| 2504 | return 1; |
| 2505 | } |
| 2506 | } |
| 2507 | |
| 2508 | return 0; |
| 2509 | } |
| 2510 | |
| 2511 | |
| 2512 | |
| 2513 | /* |
| 2514 | * Report the number of stones in a string. |
| 2515 | */ |
| 2516 | |
| 2517 | int |
| 2518 | countstones(int str) |
| 2519 | { |
| 2520 | ASSERT_ON_BOARD1(str); |
| 2521 | ASSERT1(IS_STONE(board[str]), str); |
| 2522 | |
| 2523 | return COUNTSTONES(str); |
| 2524 | } |
| 2525 | |
| 2526 | |
| 2527 | /* Find the stones of the string at str. str must not be |
| 2528 | * empty. The locations of up to maxstones stones are written into |
| 2529 | * stones[]. The full number of stones is returned. |
| 2530 | */ |
| 2531 | |
| 2532 | int |
| 2533 | findstones(int str, int maxstones, int *stones) |
| 2534 | { |
| 2535 | int s; |
| 2536 | int size; |
| 2537 | int pos; |
| 2538 | int k; |
| 2539 | |
| 2540 | ASSERT_ON_BOARD1(str); |
| 2541 | ASSERT1(IS_STONE(board[str]), str); |
| 2542 | |
| 2543 | s = string_number[str]; |
| 2544 | size = string[s].size; |
| 2545 | |
| 2546 | /* Traverse the stones of the string, by following the cyclic chain. */ |
| 2547 | pos = FIRST_STONE(s); |
| 2548 | for (k = 0; k < maxstones && k < size; k++) { |
| 2549 | stones[k] = pos; |
| 2550 | pos = NEXT_STONE(pos); |
| 2551 | } |
| 2552 | |
| 2553 | return size; |
| 2554 | } |
| 2555 | |
| 2556 | |
| 2557 | /* Counts how many stones in str1 are directly adjacent to str2. |
| 2558 | * A limit can be given in the maxstones parameter so that the |
| 2559 | * function returns immediately. See fast_defense() in reading.c |
| 2560 | */ |
| 2561 | |
| 2562 | int |
| 2563 | count_adjacent_stones(int str1, int str2, int maxstones) |
| 2564 | { |
| 2565 | int s1, s2; |
| 2566 | int size; |
| 2567 | int pos; |
| 2568 | int k; |
| 2569 | int count = 0; |
| 2570 | |
| 2571 | ASSERT_ON_BOARD1(str1); |
| 2572 | ASSERT1(IS_STONE(board[str1]), str1); |
| 2573 | ASSERT_ON_BOARD1(str2); |
| 2574 | ASSERT1(IS_STONE(board[str2]), str2); |
| 2575 | |
| 2576 | s1 = string_number[str1]; |
| 2577 | s2 = string_number[str2]; |
| 2578 | size = string[s1].size; |
| 2579 | |
| 2580 | /* Traverse the stones of the string, by following the cyclic chain. */ |
| 2581 | pos = FIRST_STONE(s1); |
| 2582 | for (k = 0; k < size && count < maxstones; k++) { |
| 2583 | if (NEIGHBOR_OF_STRING(pos, s2, board[str2])) |
| 2584 | count++; |
| 2585 | pos = NEXT_STONE(pos); |
| 2586 | } |
| 2587 | |
| 2588 | return count; |
| 2589 | } |
| 2590 | |
| 2591 | |
| 2592 | /* chainlinks returns (in the (adj) array) the chains surrounding |
| 2593 | * the string at (str). The number of chains is returned. |
| 2594 | */ |
| 2595 | |
| 2596 | int |
| 2597 | chainlinks(int str, int adj[MAXCHAIN]) |
| 2598 | { |
| 2599 | struct string_data *s; |
| 2600 | struct string_neighbors_data *sn; |
| 2601 | int k; |
| 2602 | |
| 2603 | ASSERT1(IS_STONE(board[str]), str); |
| 2604 | |
| 2605 | /* We already have the list ready, just copy it and fill in the |
| 2606 | * desired information. |
| 2607 | */ |
| 2608 | s = &string[string_number[str]]; |
| 2609 | sn = &string_neighbors[string_number[str]]; |
| 2610 | for (k = 0; k < s->neighbors; k++) |
| 2611 | adj[k] = string[sn->list[k]].origin; |
| 2612 | |
| 2613 | return s->neighbors; |
| 2614 | } |
| 2615 | |
| 2616 | |
| 2617 | /* chainlinks2 returns (in adj array) those chains surrounding |
| 2618 | * the string at str which have exactly lib liberties. The number |
| 2619 | * of such chains is returned. |
| 2620 | */ |
| 2621 | |
| 2622 | int |
| 2623 | chainlinks2(int str, int adj[MAXCHAIN], int lib) |
| 2624 | { |
| 2625 | struct string_data *s, *t; |
| 2626 | struct string_neighbors_data *sn; |
| 2627 | int k; |
| 2628 | int neighbors; |
| 2629 | |
| 2630 | ASSERT1(IS_STONE(board[str]), str); |
| 2631 | |
| 2632 | /* We already have the list ready, just copy the strings with the |
| 2633 | * right number of liberties. |
| 2634 | */ |
| 2635 | neighbors = 0; |
| 2636 | s = &string[string_number[str]]; |
| 2637 | sn = &string_neighbors[string_number[str]]; |
| 2638 | for (k = 0; k < s->neighbors; k++) { |
| 2639 | t = &string[sn->list[k]]; |
| 2640 | if (t->liberties == lib) |
| 2641 | adj[neighbors++] = t->origin; |
| 2642 | } |
| 2643 | return neighbors; |
| 2644 | } |
| 2645 | |
| 2646 | |
| 2647 | /* chainlinks3 returns (in adj array) those chains surrounding |
| 2648 | * the string at str, which have less or equal lib liberties. |
| 2649 | * The number of such chains is returned. |
| 2650 | */ |
| 2651 | |
| 2652 | int |
| 2653 | chainlinks3(int str, int adj[MAXCHAIN], int lib) |
| 2654 | { |
| 2655 | struct string_data *s, *t; |
| 2656 | struct string_neighbors_data *sn; |
| 2657 | int k; |
| 2658 | int neighbors; |
| 2659 | |
| 2660 | ASSERT1(IS_STONE(board[str]), str); |
| 2661 | |
| 2662 | /* We already have the list ready, just copy the strings with the |
| 2663 | * right number of liberties. |
| 2664 | */ |
| 2665 | neighbors = 0; |
| 2666 | s = &string[string_number[str]]; |
| 2667 | sn = &string_neighbors[string_number[str]]; |
| 2668 | for (k = 0; k < s->neighbors; k++) { |
| 2669 | t = &string[sn->list[k]]; |
| 2670 | if (t->liberties <= lib) |
| 2671 | adj[neighbors++] = t->origin; |
| 2672 | } |
| 2673 | return neighbors; |
| 2674 | } |
| 2675 | |
| 2676 | |
| 2677 | /* extended_chainlinks() returns (in the (adj) array) the opponent |
| 2678 | * strings being directly adjacent to (str) or having a common liberty |
| 2679 | * with (str). The number of such strings is returned. |
| 2680 | * |
| 2681 | * If the both_colors parameter is true, also own strings sharing a |
| 2682 | * liberty are returned. |
| 2683 | */ |
| 2684 | |
| 2685 | int |
| 2686 | extended_chainlinks(int str, int adj[MAXCHAIN], int both_colors) |
| 2687 | { |
| 2688 | struct string_data *s; |
| 2689 | struct string_neighbors_data *sn; |
| 2690 | int n; |
| 2691 | int k; |
| 2692 | int r; |
| 2693 | int libs[MAXLIBS]; |
| 2694 | int liberties; |
| 2695 | |
| 2696 | ASSERT1(IS_STONE(board[str]), str); |
| 2697 | |
| 2698 | /* We already have the list of directly adjacent strings ready, just |
| 2699 | * copy it and mark the strings. |
| 2700 | */ |
| 2701 | s = &string[string_number[str]]; |
| 2702 | sn = &string_neighbors[string_number[str]]; |
| 2703 | string_mark++; |
| 2704 | for (n = 0; n < s->neighbors; n++) { |
| 2705 | adj[n] = string[sn->list[n]].origin; |
| 2706 | MARK_STRING(adj[n]); |
| 2707 | } |
| 2708 | |
| 2709 | /* Get the liberties. */ |
| 2710 | liberties = findlib(str, MAXLIBS, libs); |
| 2711 | |
| 2712 | /* Look for unmarked opponent strings next to a liberty and add the |
| 2713 | * ones which are found to the output. |
| 2714 | */ |
| 2715 | for (r = 0; r < liberties; r++) { |
| 2716 | for (k = 0; k < 4; k++) { |
| 2717 | if ((board[libs[r] + delta[k]] == OTHER_COLOR(board[str]) |
| 2718 | || (both_colors && board[libs[r] + delta[k]] == board[str])) |
| 2719 | && UNMARKED_STRING(libs[r] + delta[k])) { |
| 2720 | adj[n] = string[string_number[libs[r] + delta[k]]].origin; |
| 2721 | MARK_STRING(adj[n]); |
| 2722 | n++; |
| 2723 | } |
| 2724 | } |
| 2725 | } |
| 2726 | |
| 2727 | return n; |
| 2728 | } |
| 2729 | |
| 2730 | |
| 2731 | /* Returns true if a move by (color) fits a shape like: |
| 2732 | * |
| 2733 | * ----- |
| 2734 | * O.O*X (O=color) |
| 2735 | * OOXXX |
| 2736 | * |
| 2737 | * More specifically the move should have the following properties: |
| 2738 | * - The move is a self-atari |
| 2739 | * - The move forms a string of exactly two stones |
| 2740 | * - When the opponent captures, the capturing stone becomes a single |
| 2741 | * stone in atari |
| 2742 | * - When capturing back the original position is repeated |
| 2743 | */ |
| 2744 | |
| 2745 | int |
| 2746 | send_two_return_one(int move, int color) |
| 2747 | { |
| 2748 | int other = OTHER_COLOR(color); |
| 2749 | int lib = NO_MOVE; |
| 2750 | int friendly_neighbor = NO_MOVE; |
| 2751 | int k; |
| 2752 | |
| 2753 | ASSERT1(board[move] == EMPTY, move); |
| 2754 | |
| 2755 | for (k = 0; k < 4; k++) { |
| 2756 | int pos = move + delta[k]; |
| 2757 | if (board[pos] == EMPTY) |
| 2758 | return 0; |
| 2759 | if (board[pos] == color) { |
| 2760 | int s; |
| 2761 | if (friendly_neighbor != NO_MOVE) |
| 2762 | return 0; |
| 2763 | friendly_neighbor = pos; |
| 2764 | s = string_number[pos]; |
| 2765 | if (string[s].size != 1 || string[s].liberties != 2) |
| 2766 | return 0; |
| 2767 | lib = string_libs[s].list[0] + string_libs[s].list[1] - move; |
| 2768 | } |
| 2769 | else if (board[pos] == other |
| 2770 | && string[string_number[pos]].liberties == 1) |
| 2771 | return 0; |
| 2772 | } |
| 2773 | |
| 2774 | if (friendly_neighbor == NO_MOVE) |
| 2775 | return 0; |
| 2776 | |
| 2777 | for (k = 0; k < 4; k++) { |
| 2778 | int pos = lib + delta[k]; |
| 2779 | if (board[pos] == EMPTY || board[pos] == other) |
| 2780 | return 0; |
| 2781 | if (board[pos] == color && |
| 2782 | string[string_number[pos]].liberties < 2) |
| 2783 | return 0; |
| 2784 | } |
| 2785 | |
| 2786 | return 1; |
| 2787 | } |
| 2788 | |
| 2789 | |
| 2790 | /* |
| 2791 | * Find the origin of a worm, i.e. the point with the |
| 2792 | * smallest 1D board coordinate. The idea is to have a canonical |
| 2793 | * reference point for a string. |
| 2794 | */ |
| 2795 | |
| 2796 | int |
| 2797 | find_origin(int str) |
| 2798 | { |
| 2799 | ASSERT1(IS_STONE(board[str]), str); |
| 2800 | |
| 2801 | return string[string_number[str]].origin; |
| 2802 | } |
| 2803 | |
| 2804 | |
| 2805 | /* Determine whether a move by color at (pos) would be a self atari, |
| 2806 | * i.e. whether it would get more than one liberty. This function |
| 2807 | * returns true also for the case of a suicide move. |
| 2808 | */ |
| 2809 | |
| 2810 | int |
| 2811 | is_self_atari(int pos, int color) |
| 2812 | { |
| 2813 | int other = OTHER_COLOR(color); |
| 2814 | /* number of empty neighbors */ |
| 2815 | int trivial_liberties = 0; |
| 2816 | /* number of captured opponent strings */ |
| 2817 | int captures = 0; |
| 2818 | /* Whether there is a friendly neighbor with a spare liberty. If it |
| 2819 | * has more than one spare liberty we immediately return 0. |
| 2820 | */ |
| 2821 | int far_liberties = 0; |
| 2822 | |
| 2823 | ASSERT_ON_BOARD1(pos); |
| 2824 | ASSERT1(board[pos] == EMPTY, pos); |
| 2825 | ASSERT1(IS_STONE(color), pos); |
| 2826 | |
| 2827 | /* 1. Try first to solve the problem without much work. */ |
| 2828 | string_mark++; |
| 2829 | |
| 2830 | if (LIBERTY(SOUTH(pos))) |
| 2831 | trivial_liberties++; |
| 2832 | else if (board[SOUTH(pos)] == color) { |
| 2833 | if (LIBERTIES(SOUTH(pos)) > 2) |
| 2834 | return 0; |
| 2835 | if (LIBERTIES(SOUTH(pos)) == 2) |
| 2836 | far_liberties++; |
| 2837 | } |
| 2838 | else if (board[SOUTH(pos)] == other |
| 2839 | && LIBERTIES(SOUTH(pos)) == 1 && UNMARKED_STRING(SOUTH(pos))) { |
| 2840 | captures++; |
| 2841 | MARK_STRING(SOUTH(pos)); |
| 2842 | } |
| 2843 | |
| 2844 | if (LIBERTY(WEST(pos))) |
| 2845 | trivial_liberties++; |
| 2846 | else if (board[WEST(pos)] == color) { |
| 2847 | if (LIBERTIES(WEST(pos)) > 2) |
| 2848 | return 0; |
| 2849 | if (LIBERTIES(WEST(pos)) == 2) |
| 2850 | far_liberties++; |
| 2851 | } |
| 2852 | else if (board[WEST(pos)] == other |
| 2853 | && LIBERTIES(WEST(pos)) == 1 && UNMARKED_STRING(WEST(pos))) { |
| 2854 | captures++; |
| 2855 | MARK_STRING(WEST(pos)); |
| 2856 | } |
| 2857 | |
| 2858 | if (LIBERTY(NORTH(pos))) |
| 2859 | trivial_liberties++; |
| 2860 | else if (board[NORTH(pos)] == color) { |
| 2861 | if (LIBERTIES(NORTH(pos)) > 2) |
| 2862 | return 0; |
| 2863 | if (LIBERTIES(NORTH(pos)) == 2) |
| 2864 | far_liberties++; |
| 2865 | } |
| 2866 | else if (board[NORTH(pos)] == other |
| 2867 | && LIBERTIES(NORTH(pos)) == 1 && UNMARKED_STRING(NORTH(pos))) { |
| 2868 | captures++; |
| 2869 | MARK_STRING(NORTH(pos)); |
| 2870 | } |
| 2871 | |
| 2872 | if (LIBERTY(EAST(pos))) |
| 2873 | trivial_liberties++; |
| 2874 | else if (board[EAST(pos)] == color) { |
| 2875 | if (LIBERTIES(EAST(pos)) > 2) |
| 2876 | return 0; |
| 2877 | if (LIBERTIES(EAST(pos)) == 2) |
| 2878 | far_liberties++; |
| 2879 | } |
| 2880 | else if (board[EAST(pos)] == other |
| 2881 | && LIBERTIES(EAST(pos)) == 1 && UNMARKED_STRING(EAST(pos))) { |
| 2882 | captures++; |
| 2883 | #if 0 |
| 2884 | MARK_STRING(EAST(pos)); |
| 2885 | #endif |
| 2886 | } |
| 2887 | |
| 2888 | /* Each captured string is guaranteed to produce at least one |
| 2889 | * liberty. These are disjoint from both trivial liberties and far |
| 2890 | * liberties. The two latter may however coincide. |
| 2891 | */ |
| 2892 | if (trivial_liberties + captures >= 2) |
| 2893 | return 0; |
| 2894 | |
| 2895 | if ((far_liberties > 0) + captures >= 2) |
| 2896 | return 0; |
| 2897 | |
| 2898 | if (captures == 0 && far_liberties + trivial_liberties <= 1) |
| 2899 | return 1; |
| 2900 | |
| 2901 | /* 2. It was not so easy. We use accuratelib() in this case. */ |
| 2902 | return accuratelib(pos, color, 2, NULL) <= 1; |
| 2903 | } |
| 2904 | |
| 2905 | |
| 2906 | /* |
| 2907 | * Returns true if pos is a liberty of the string at str. |
| 2908 | */ |
| 2909 | |
| 2910 | int |
| 2911 | liberty_of_string(int pos, int str) |
| 2912 | { |
| 2913 | ASSERT_ON_BOARD1(pos); |
| 2914 | ASSERT_ON_BOARD1(str); |
| 2915 | if (IS_STONE(board[pos])) |
| 2916 | return 0; |
| 2917 | |
| 2918 | return NEIGHBOR_OF_STRING(pos, string_number[str], board[str]); |
| 2919 | } |
| 2920 | |
| 2921 | |
| 2922 | /* |
| 2923 | * Returns true if pos is a second order liberty of the string at str. |
| 2924 | */ |
| 2925 | int |
| 2926 | second_order_liberty_of_string(int pos, int str) |
| 2927 | { |
| 2928 | int k; |
| 2929 | ASSERT_ON_BOARD1(pos); |
| 2930 | ASSERT_ON_BOARD1(str); |
| 2931 | |
| 2932 | for (k = 0; k < 4; k++) |
| 2933 | if (board[pos + delta[k]] == EMPTY |
| 2934 | && NEIGHBOR_OF_STRING(pos + delta[k], string_number[str], board[str])) |
| 2935 | return 1; |
| 2936 | |
| 2937 | return 0; |
| 2938 | } |
| 2939 | |
| 2940 | |
| 2941 | /* |
| 2942 | * Returns true if pos is adjacent to the string at str. |
| 2943 | */ |
| 2944 | |
| 2945 | int |
| 2946 | neighbor_of_string(int pos, int str) |
| 2947 | { |
| 2948 | int color = board[str]; |
| 2949 | |
| 2950 | ASSERT1(IS_STONE(color), str); |
| 2951 | ASSERT_ON_BOARD1(pos); |
| 2952 | |
| 2953 | return NEIGHBOR_OF_STRING(pos, string_number[str], color); |
| 2954 | } |
| 2955 | |
| 2956 | /* |
| 2957 | * Returns true if (pos) has a neighbor of color (color). |
| 2958 | */ |
| 2959 | |
| 2960 | int |
| 2961 | has_neighbor(int pos, int color) |
| 2962 | { |
| 2963 | ASSERT_ON_BOARD1(pos); |
| 2964 | ASSERT1(IS_STONE(color), pos); |
| 2965 | |
| 2966 | return (board[SOUTH(pos)] == color |
| 2967 | || board[WEST(pos)] == color |
| 2968 | || board[NORTH(pos)] == color |
| 2969 | || board[EAST(pos)] == color); |
| 2970 | } |
| 2971 | |
| 2972 | /* |
| 2973 | * Returns true if str1 and str2 belong to the same string. |
| 2974 | */ |
| 2975 | |
| 2976 | int |
| 2977 | same_string(int str1, int str2) |
| 2978 | { |
| 2979 | ASSERT_ON_BOARD1(str1); |
| 2980 | ASSERT_ON_BOARD1(str2); |
| 2981 | ASSERT1(IS_STONE(board[str1]), str1); |
| 2982 | ASSERT1(IS_STONE(board[str2]), str2); |
| 2983 | |
| 2984 | return string_number[str1] == string_number[str2]; |
| 2985 | } |
| 2986 | |
| 2987 | |
| 2988 | /* |
| 2989 | * Returns true if the strings at str1 and str2 are adjacent. |
| 2990 | */ |
| 2991 | |
| 2992 | int |
| 2993 | adjacent_strings(int str1, int str2) |
| 2994 | { |
| 2995 | int s1, s2; |
| 2996 | int k; |
| 2997 | |
| 2998 | ASSERT_ON_BOARD1(str1); |
| 2999 | ASSERT_ON_BOARD1(str2); |
| 3000 | ASSERT1(IS_STONE(board[str1]), str1); |
| 3001 | ASSERT1(IS_STONE(board[str2]), str2); |
| 3002 | |
| 3003 | s1 = string_number[str1]; |
| 3004 | s2 = string_number[str2]; |
| 3005 | |
| 3006 | for (k = 0; k < string[s1].neighbors; k++) |
| 3007 | if (string_neighbors[s1].list[k] == s2) |
| 3008 | return 1; |
| 3009 | |
| 3010 | return 0; |
| 3011 | } |
| 3012 | |
| 3013 | |
| 3014 | /* |
| 3015 | * Return true if the move (pos) by (color) is a ko capture |
| 3016 | * (whether capture is legal on this move or not). If so, |
| 3017 | * and if ko_pos is not a NULL pointer, then |
| 3018 | * *ko_pos returns the location of the captured ko stone. |
| 3019 | * If the move is not a ko capture, *ko_pos is set to 0. |
| 3020 | * |
| 3021 | * A move is a ko capture if and only if |
| 3022 | * 1. All neighbors are opponent stones. |
| 3023 | * 2. The number of captured stones is exactly one. |
| 3024 | */ |
| 3025 | |
| 3026 | int |
| 3027 | is_ko(int pos, int color, int *ko_pos) |
| 3028 | { |
| 3029 | int other = OTHER_COLOR(color); |
| 3030 | int captures = 0; |
| 3031 | int kpos = 0; |
| 3032 | |
| 3033 | ASSERT_ON_BOARD1(pos); |
| 3034 | ASSERT1(color == WHITE || color == BLACK, pos); |
| 3035 | |
| 3036 | if (ON_BOARD(SOUTH(pos))) { |
| 3037 | if (board[SOUTH(pos)] != other) |
| 3038 | return 0; |
| 3039 | else if (LIBERTIES(SOUTH(pos)) == 1) { |
| 3040 | kpos = SOUTH(pos); |
| 3041 | captures += string[string_number[SOUTH(pos)]].size; |
| 3042 | if (captures > 1) |
| 3043 | return 0; |
| 3044 | } |
| 3045 | } |
| 3046 | |
| 3047 | if (ON_BOARD(WEST(pos))) { |
| 3048 | if (board[WEST(pos)] != other) |
| 3049 | return 0; |
| 3050 | else if (LIBERTIES(WEST(pos)) == 1) { |
| 3051 | kpos = WEST(pos); |
| 3052 | captures += string[string_number[WEST(pos)]].size; |
| 3053 | if (captures > 1) |
| 3054 | return 0; |
| 3055 | } |
| 3056 | } |
| 3057 | |
| 3058 | if (ON_BOARD(NORTH(pos))) { |
| 3059 | if (board[NORTH(pos)] != other) |
| 3060 | return 0; |
| 3061 | else if (LIBERTIES(NORTH(pos)) == 1) { |
| 3062 | kpos = NORTH(pos); |
| 3063 | captures += string[string_number[NORTH(pos)]].size; |
| 3064 | if (captures > 1) |
| 3065 | return 0; |
| 3066 | } |
| 3067 | } |
| 3068 | |
| 3069 | if (ON_BOARD(EAST(pos))) { |
| 3070 | if (board[EAST(pos)] != other) |
| 3071 | return 0; |
| 3072 | else if (LIBERTIES(EAST(pos)) == 1) { |
| 3073 | kpos = EAST(pos); |
| 3074 | captures += string[string_number[EAST(pos)]].size; |
| 3075 | if (captures > 1) |
| 3076 | return 0; |
| 3077 | } |
| 3078 | } |
| 3079 | |
| 3080 | if (captures == 1) { |
| 3081 | if (ko_pos) |
| 3082 | *ko_pos = kpos; |
| 3083 | return 1; |
| 3084 | } |
| 3085 | return 0; |
| 3086 | } |
| 3087 | |
| 3088 | |
| 3089 | /* Return true if pos is either a stone, which if captured would give |
| 3090 | * ko, or if pos is an empty intersection adjacent to a ko stone. |
| 3091 | */ |
| 3092 | int |
| 3093 | is_ko_point(int pos) |
| 3094 | { |
| 3095 | ASSERT_ON_BOARD1(pos); |
| 3096 | |
| 3097 | if (board[pos] == EMPTY) { |
| 3098 | int color; |
| 3099 | if (ON_BOARD(SOUTH(pos))) |
| 3100 | color = board[SOUTH(pos)]; |
| 3101 | else |
| 3102 | color = board[NORTH(pos)]; |
| 3103 | if (IS_STONE(color) && is_ko(pos, OTHER_COLOR(color), NULL)) |
| 3104 | return 1; |
| 3105 | } |
| 3106 | else { |
| 3107 | struct string_data *s = &string[string_number[pos]]; |
| 3108 | struct string_liberties_data *sl = &string_libs[string_number[pos]]; |
| 3109 | if (s->liberties == 1 && s->size == 1 |
| 3110 | && is_ko(sl->list[0], OTHER_COLOR(s->color), NULL)) |
| 3111 | return 1; |
| 3112 | } |
| 3113 | |
| 3114 | return 0; |
| 3115 | } |
| 3116 | |
| 3117 | |
| 3118 | /* Return true if a move by color at pos is a superko violation |
| 3119 | * according to the specified type of ko rules. This function does not |
| 3120 | * detect simple ko unless it's also a superko violation. |
| 3121 | * |
| 3122 | * The superko detection is done by comparing board hashes from |
| 3123 | * previous positions. For this to work correctly it's necessary to |
| 3124 | * remove the contribution to the hash from the simple ko position. |
| 3125 | * The move_history_hash array contains board hashes for previous |
| 3126 | * positions, also without simple ko position contributions. |
| 3127 | */ |
| 3128 | static int |
| 3129 | is_superko_violation(int pos, int color, enum ko_rules type) |
| 3130 | { |
| 3131 | Hash_data this_board_hash = board_hash; |
| 3132 | Hash_data new_board_hash; |
| 3133 | int k; |
| 3134 | |
| 3135 | /* No superko violations if the ko rule is not a superko rule. */ |
| 3136 | if (type == NONE || type == SIMPLE) |
| 3137 | return 0; |
| 3138 | |
| 3139 | if (board_ko_pos != NO_MOVE) |
| 3140 | hashdata_invert_ko(&this_board_hash, board_ko_pos); |
| 3141 | |
| 3142 | really_do_trymove(pos, color); |
| 3143 | new_board_hash = board_hash; |
| 3144 | if (board_ko_pos != NO_MOVE) |
| 3145 | hashdata_invert_ko(&new_board_hash, board_ko_pos); |
| 3146 | undo_trymove(); |
| 3147 | |
| 3148 | /* The current position is only a problem with positional superko |
| 3149 | * and a single stone suicide. |
| 3150 | */ |
| 3151 | if (type == PSK && hashdata_is_equal(this_board_hash, new_board_hash)) |
| 3152 | return 1; |
| 3153 | |
| 3154 | for (k = move_history_pointer - 1; k >= 0; k--) |
| 3155 | if (hashdata_is_equal(move_history_hash[k], new_board_hash) |
| 3156 | && (type == PSK |
| 3157 | || move_history_color[k] == OTHER_COLOR(color))) |
| 3158 | return 1; |
| 3159 | |
| 3160 | return 0; |
| 3161 | } |
| 3162 | |
| 3163 | /* Returns 1 if at least one string is captured when color plays at pos. |
| 3164 | */ |
| 3165 | int |
| 3166 | does_capture_something(int pos, int color) |
| 3167 | { |
| 3168 | int other = OTHER_COLOR(color); |
| 3169 | |
| 3170 | ASSERT1(board[pos] == EMPTY, pos); |
| 3171 | |
| 3172 | if (board[SOUTH(pos)] == other && LIBERTIES(SOUTH(pos)) == 1) |
| 3173 | return 1; |
| 3174 | |
| 3175 | if (board[WEST(pos)] == other && LIBERTIES(WEST(pos)) == 1) |
| 3176 | return 1; |
| 3177 | |
| 3178 | if (board[NORTH(pos)] == other && LIBERTIES(NORTH(pos)) == 1) |
| 3179 | return 1; |
| 3180 | |
| 3181 | if (board[EAST(pos)] == other && LIBERTIES(EAST(pos)) == 1) |
| 3182 | return 1; |
| 3183 | |
| 3184 | return 0; |
| 3185 | } |
| 3186 | |
| 3187 | |
| 3188 | /* For each stone in the string at pos, set mx to value mark. */ |
| 3189 | void |
| 3190 | mark_string(int str, signed char mx[BOARDMAX], signed char mark) |
| 3191 | { |
| 3192 | int pos = str; |
| 3193 | |
| 3194 | ASSERT1(IS_STONE(board[str]), str); |
| 3195 | |
| 3196 | do { |
| 3197 | mx[pos] = mark; |
| 3198 | pos = NEXT_STONE(pos); |
| 3199 | } while (pos != str); |
| 3200 | } |
| 3201 | |
| 3202 | |
| 3203 | /* Returns true if at least one move has been played at pos |
| 3204 | * at deeper than level 'cutoff' in the reading tree. |
| 3205 | */ |
| 3206 | int |
| 3207 | move_in_stack(int pos, int cutoff) |
| 3208 | { |
| 3209 | int k; |
| 3210 | for (k = cutoff; k < stackp; k++) |
| 3211 | if (stack[k] == pos) |
| 3212 | return 1; |
| 3213 | |
| 3214 | return 0; |
| 3215 | } |
| 3216 | |
| 3217 | |
| 3218 | /* Retrieve a move from the move stack. */ |
| 3219 | void |
| 3220 | get_move_from_stack(int k, int *move, int *color) |
| 3221 | { |
| 3222 | gg_assert(k < stackp); |
| 3223 | *move = stack[k]; |
| 3224 | *color = move_color[k]; |
| 3225 | } |
| 3226 | |
| 3227 | /* Return the number of stones of the indicated color(s) on the board. |
| 3228 | * This only counts stones in the permanent position, not stones placed |
| 3229 | * by trymove() or tryko(). Use stones_on_board(BLACK | WHITE) to get |
| 3230 | * the total number of stones on the board. |
| 3231 | * |
| 3232 | * FIXME: This seems wrong, it uses the modified board, not the permanent |
| 3233 | * one. /ab |
| 3234 | */ |
| 3235 | int |
| 3236 | stones_on_board(int color) |
| 3237 | { |
| 3238 | static int stone_count_for_position = -1; |
| 3239 | static int white_stones = 0; |
| 3240 | static int black_stones = 0; |
| 3241 | |
| 3242 | gg_assert(stackp == 0); |
| 3243 | |
| 3244 | if (stone_count_for_position != position_number) { |
| 3245 | int pos; |
| 3246 | white_stones = 0; |
| 3247 | black_stones = 0; |
| 3248 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 3249 | if (board[pos] == WHITE) |
| 3250 | white_stones++; |
| 3251 | else if (board[pos] == BLACK) |
| 3252 | black_stones++; |
| 3253 | } |
| 3254 | |
| 3255 | stone_count_for_position = position_number; |
| 3256 | } |
| 3257 | |
| 3258 | return ((color & BLACK ? black_stones : 0) + |
| 3259 | (color & WHITE ? white_stones : 0)); |
| 3260 | } |
| 3261 | |
| 3262 | |
| 3263 | /* ===================== Statistics ============================= */ |
| 3264 | |
| 3265 | |
| 3266 | /* Clear statistics. */ |
| 3267 | void |
| 3268 | reset_trymove_counter() |
| 3269 | { |
| 3270 | trymove_counter = 0; |
| 3271 | } |
| 3272 | |
| 3273 | |
| 3274 | /* Retrieve statistics. */ |
| 3275 | int |
| 3276 | get_trymove_counter() |
| 3277 | { |
| 3278 | return trymove_counter; |
| 3279 | } |
| 3280 | |
| 3281 | |
| 3282 | /* ================================================================ */ |
| 3283 | /* Lower level functions */ |
| 3284 | /* ================================================================ */ |
| 3285 | |
| 3286 | |
| 3287 | /* This function should be called if the board is modified by other |
| 3288 | * means than do_play_move() or undo_trymove(). |
| 3289 | * |
| 3290 | * We have reached a new position. Increase the position counter and |
| 3291 | * re-initialize the incremental strings. |
| 3292 | * |
| 3293 | * Set up incremental board structures and populate them with the |
| 3294 | * strings available in the position given by board[]. Clear the stacks |
| 3295 | * and start the mark numbers from zero. All undo information is lost |
| 3296 | * by calling this function. |
| 3297 | */ |
| 3298 | |
| 3299 | static void |
| 3300 | new_position(void) |
| 3301 | { |
| 3302 | int pos; |
| 3303 | int s; |
| 3304 | |
| 3305 | position_number++; |
| 3306 | next_string = 0; |
| 3307 | liberty_mark = 0; |
| 3308 | string_mark = 0; |
| 3309 | CLEAR_STACKS(); |
| 3310 | |
| 3311 | memset(string, 0, sizeof(string)); |
| 3312 | memset(string_libs, 0, sizeof(string_libs)); |
| 3313 | memset(string_neighbors, 0, sizeof(string_neighbors)); |
| 3314 | memset(ml, 0, sizeof(ml)); |
| 3315 | VALGRIND_MAKE_WRITABLE(next_stone, sizeof(next_stone)); |
| 3316 | |
| 3317 | /* propagate_string relies on non-assigned stones to have |
| 3318 | * string_number -1. |
| 3319 | */ |
| 3320 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) |
| 3321 | if (ON_BOARD(pos)) |
| 3322 | string_number[pos] = -1; |
| 3323 | |
| 3324 | /* Find the existing strings. */ |
| 3325 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 3326 | if (!ON_BOARD(pos)) |
| 3327 | continue; |
| 3328 | if (IS_STONE(board[pos]) && string_number[pos] == -1) { |
| 3329 | string_number[pos] = next_string; |
| 3330 | string[next_string].size = propagate_string(pos, pos); |
| 3331 | string[next_string].color = board[pos]; |
| 3332 | string[next_string].origin = pos; |
| 3333 | string[next_string].mark = 0; |
| 3334 | next_string++; |
| 3335 | PARANOID1(next_string < MAX_STRINGS, pos); |
| 3336 | } |
| 3337 | } |
| 3338 | |
| 3339 | /* Fill in liberty and neighbor info. */ |
| 3340 | for (s = 0; s < next_string; s++) { |
| 3341 | find_liberties_and_neighbors(s); |
| 3342 | } |
| 3343 | } |
| 3344 | |
| 3345 | |
| 3346 | #if 0 |
| 3347 | |
| 3348 | /* |
| 3349 | * Debug function. Dump all string information. |
| 3350 | */ |
| 3351 | |
| 3352 | static void |
| 3353 | dump_incremental_board(void) |
| 3354 | { |
| 3355 | int pos; |
| 3356 | int s; |
| 3357 | int i; |
| 3358 | |
| 3359 | for (pos = BOARDMIN; pos < BOARDMAX; pos++) { |
| 3360 | if (!ON_BOARD(pos)) |
| 3361 | continue; |
| 3362 | if (board[pos] == EMPTY) |
| 3363 | fprintf(stderr, " . "); |
| 3364 | else |
| 3365 | fprintf(stderr, "%2d ", string_number[pos]); |
| 3366 | fprintf(stderr, "\n"); |
| 3367 | } |
| 3368 | |
| 3369 | for (s = 0; s < next_string; s++) { |
| 3370 | if (board[string[s].origin] == EMPTY) |
| 3371 | continue; |
| 3372 | |
| 3373 | gprintf("%o%d %s %1m size %d, %d liberties, %d neighbors\n", s, |
| 3374 | color_to_string(string[s].color), |
| 3375 | string[s].origin, string[s].size, |
| 3376 | string[s].liberties, string[s].neighbors); |
| 3377 | gprintf("%ostones:"); |
| 3378 | |
| 3379 | pos = FIRST_STONE(s); |
| 3380 | do { |
| 3381 | gprintf("%o %1m", pos); |
| 3382 | pos = NEXT_STONE(pos); |
| 3383 | } while (!BACK_TO_FIRST_STONE(s, pos)); |
| 3384 | |
| 3385 | gprintf("%o\nliberties:"); |
| 3386 | for (i = 0; i < string[s].liberties; i++) |
| 3387 | gprintf("%o %1m", string[s].libs[i]); |
| 3388 | |
| 3389 | gprintf("%o\nneighbors:"); |
| 3390 | for (i = 0; i < string[s].neighbors; i++) |
| 3391 | gprintf("%o %d(%1m)", string[s].neighborlist[i], |
| 3392 | string[string[s].neighborlist[i]].origin); |
| 3393 | gprintf("%o\n\n"); |
| 3394 | } |
| 3395 | } |
| 3396 | #endif |
| 3397 | |
| 3398 | |
| 3399 | /* Build a string and its cyclic list representation from scratch. |
| 3400 | * propagate_string(stone, str) adds the stone (stone) to the string |
| 3401 | * (str) and recursively continues with not already included friendly |
| 3402 | * neighbors. To start a new string at (stone), use |
| 3403 | * propagate_string(stone, stone). The size of the string is returned. |
| 3404 | */ |
| 3405 | |
| 3406 | static int |
| 3407 | propagate_string(int stone, int str) |
| 3408 | { |
| 3409 | int size = 1; |
| 3410 | int k; |
| 3411 | |
| 3412 | if (stone == str) { |
| 3413 | /* Start a new string. */ |
| 3414 | next_stone[stone] = stone; |
| 3415 | } |
| 3416 | else { |
| 3417 | /* Link the stone at (stone) to the string including (str) */ |
| 3418 | string_number[stone] = string_number[str]; |
| 3419 | next_stone[stone] = next_stone[str]; |
| 3420 | next_stone[str] = stone; |
| 3421 | } |
| 3422 | |
| 3423 | /* Look in all four directions for more stones to add. */ |
| 3424 | for (k = 0; k < 4; k++) { |
| 3425 | int d = delta[k]; |
| 3426 | if (ON_BOARD(stone + d) |
| 3427 | && board[stone + d] == board[stone] |
| 3428 | && string_number[stone + d] == -1) |
| 3429 | size += propagate_string(stone + d, str); |
| 3430 | } |
| 3431 | |
| 3432 | return size; |
| 3433 | } |
| 3434 | |
| 3435 | |
| 3436 | /* Build the lists of liberties and neighbors of a string from |
| 3437 | * scratch. No information is pushed onto the stack by this function. |
| 3438 | */ |
| 3439 | |
| 3440 | static void |
| 3441 | find_liberties_and_neighbors(int s) |
| 3442 | { |
| 3443 | int pos; |
| 3444 | int other = OTHER_COLOR(string[s].color); |
| 3445 | |
| 3446 | /* Clear the marks. */ |
| 3447 | liberty_mark++; |
| 3448 | string_mark++; |
| 3449 | |
| 3450 | /* Traverse the stones of the string, by following the cyclic chain. */ |
| 3451 | pos = FIRST_STONE(s); |
| 3452 | do { |
| 3453 | /* Look in each direction for new liberties or new neighbors. Mark |
| 3454 | * already visited liberties and neighbors. |
| 3455 | */ |
| 3456 | if (UNMARKED_LIBERTY(SOUTH(pos))) { |
| 3457 | ADD_AND_MARK_LIBERTY(s, SOUTH(pos)); |
| 3458 | } |
| 3459 | else if (UNMARKED_COLOR_STRING(SOUTH(pos), other)) { |
| 3460 | ADD_NEIGHBOR(s, SOUTH(pos)); |
| 3461 | MARK_STRING(SOUTH(pos)); |
| 3462 | } |
| 3463 | |
| 3464 | if (UNMARKED_LIBERTY(WEST(pos))) { |
| 3465 | ADD_AND_MARK_LIBERTY(s, WEST(pos)); |
| 3466 | } |
| 3467 | else if (UNMARKED_COLOR_STRING(WEST(pos), other)) { |
| 3468 | ADD_NEIGHBOR(s, WEST(pos)); |
| 3469 | MARK_STRING(WEST(pos)); |
| 3470 | } |
| 3471 | |
| 3472 | if (UNMARKED_LIBERTY(NORTH(pos))) { |
| 3473 | ADD_AND_MARK_LIBERTY(s, NORTH(pos)); |
| 3474 | } |
| 3475 | else if (UNMARKED_COLOR_STRING(NORTH(pos), other)) { |
| 3476 | ADD_NEIGHBOR(s, NORTH(pos)); |
| 3477 | MARK_STRING(NORTH(pos)); |
| 3478 | } |
| 3479 | |
| 3480 | if (UNMARKED_LIBERTY(EAST(pos))) { |
| 3481 | ADD_AND_MARK_LIBERTY(s, EAST(pos)); |
| 3482 | } |
| 3483 | else if (UNMARKED_COLOR_STRING(EAST(pos), other)) { |
| 3484 | ADD_NEIGHBOR(s, EAST(pos)); |
| 3485 | MARK_STRING(EAST(pos)); |
| 3486 | } |
| 3487 | |
| 3488 | pos = NEXT_STONE(pos); |
| 3489 | } while (!BACK_TO_FIRST_STONE(s, pos)); |
| 3490 | } |
| 3491 | |
| 3492 | |
| 3493 | /* Update the liberties of a string from scratch, first pushing the |
| 3494 | * old information. |
| 3495 | */ |
| 3496 | |
| 3497 | static void |
| 3498 | update_liberties(int s) |
| 3499 | { |
| 3500 | int pos; |
| 3501 | int k; |
| 3502 | |
| 3503 | /* Push the old information. */ |
| 3504 | PUSH_VALUE(string[s].liberties); |
| 3505 | for (k = 0; k < string[s].liberties && k < MAX_LIBERTIES; k++) { |
| 3506 | PUSH_VALUE(string_libs[s].list[k]); |
| 3507 | } |
| 3508 | string[s].liberties = 0; |
| 3509 | |
| 3510 | /* Clear the liberty mark. */ |
| 3511 | liberty_mark++; |
| 3512 | |
| 3513 | /* Traverse the stones of the string, by following the cyclic chain. */ |
| 3514 | pos = FIRST_STONE(s); |
| 3515 | do { |
| 3516 | /* Look in each direction for new liberties. Mark already visited |
| 3517 | * liberties. |
| 3518 | */ |
| 3519 | if (UNMARKED_LIBERTY(SOUTH(pos))) { |
| 3520 | ADD_AND_MARK_LIBERTY(s, SOUTH(pos)); |
| 3521 | } |
| 3522 | |
| 3523 | if (UNMARKED_LIBERTY(WEST(pos))) { |
| 3524 | ADD_AND_MARK_LIBERTY(s, WEST(pos)); |
| 3525 | } |
| 3526 | |
| 3527 | if (UNMARKED_LIBERTY(NORTH(pos))) { |
| 3528 | ADD_AND_MARK_LIBERTY(s, NORTH(pos)); |
| 3529 | } |
| 3530 | |
| 3531 | if (UNMARKED_LIBERTY(EAST(pos))) { |
| 3532 | ADD_AND_MARK_LIBERTY(s, EAST(pos)); |
| 3533 | } |
| 3534 | |
| 3535 | pos = NEXT_STONE(pos); |
| 3536 | } while (!BACK_TO_FIRST_STONE(s, pos)); |
| 3537 | } |
| 3538 | |
| 3539 | |
| 3540 | /* Remove a string from the list of neighbors and push the changed |
| 3541 | * information. |
| 3542 | */ |
| 3543 | |
| 3544 | static void |
| 3545 | remove_neighbor(int str_number, int n) |
| 3546 | { |
| 3547 | int k; |
| 3548 | int done = 0; |
| 3549 | struct string_data *s = &string[str_number]; |
| 3550 | struct string_neighbors_data *sn = &string_neighbors[str_number]; |
| 3551 | for (k = 0; k < s->neighbors; k++) |
| 3552 | if (sn->list[k] == n) { |
| 3553 | /* We need to push the last entry too because it may become |
| 3554 | * destroyed later. |
| 3555 | */ |
| 3556 | PUSH_VALUE(sn->list[s->neighbors - 1]); |
| 3557 | PUSH_VALUE(sn->list[k]); |
| 3558 | PUSH_VALUE(s->neighbors); |
| 3559 | sn->list[k] = sn->list[s->neighbors - 1]; |
| 3560 | s->neighbors--; |
| 3561 | done = 1; |
| 3562 | break; |
| 3563 | } |
| 3564 | gg_assert(done); |
| 3565 | } |
| 3566 | |
| 3567 | |
| 3568 | /* Remove one liberty from the list of liberties, pushing changed |
| 3569 | * information. If the string had more liberties than the size of the |
| 3570 | * list, rebuild the list from scratch. |
| 3571 | */ |
| 3572 | |
| 3573 | static void |
| 3574 | remove_liberty(int str_number, int pos) |
| 3575 | { |
| 3576 | int k; |
| 3577 | struct string_data *s = &string[str_number]; |
| 3578 | struct string_liberties_data *sl = &string_libs[str_number]; |
| 3579 | |
| 3580 | if (s->liberties > MAX_LIBERTIES) |
| 3581 | update_liberties(str_number); |
| 3582 | else { |
| 3583 | for (k = 0; k < s->liberties; k++) |
| 3584 | if (sl->list[k] == pos) { |
| 3585 | /* We need to push the last entry too because it may become |
| 3586 | * destroyed later. |
| 3587 | */ |
| 3588 | PUSH_VALUE(sl->list[s->liberties - 1]); |
| 3589 | PUSH_VALUE(sl->list[k]); |
| 3590 | PUSH_VALUE(s->liberties); |
| 3591 | sl->list[k] = sl->list[s->liberties - 1]; |
| 3592 | s->liberties--; |
| 3593 | break; |
| 3594 | } |
| 3595 | } |
| 3596 | } |
| 3597 | |
| 3598 | |
| 3599 | /* Remove a string from the board, pushing necessary information to |
| 3600 | * restore it. Return the number of removed stones. |
| 3601 | */ |
| 3602 | |
| 3603 | static int |
| 3604 | do_remove_string(int s) |
| 3605 | { |
| 3606 | int pos; |
| 3607 | int k; |
| 3608 | int size = string[s].size; |
| 3609 | |
| 3610 | /* Traverse the stones of the string, by following the cyclic chain. */ |
| 3611 | pos = FIRST_STONE(s); |
| 3612 | do { |
| 3613 | /* Push color, string number and cyclic chain pointers. */ |
| 3614 | PUSH_VALUE(string_number[pos]); |
| 3615 | PUSH_VALUE(next_stone[pos]); |
| 3616 | DO_REMOVE_STONE(pos); |
| 3617 | pos = NEXT_STONE(pos); |
| 3618 | } while (!BACK_TO_FIRST_STONE(s, pos)); |
| 3619 | |
| 3620 | /* The neighboring strings have obtained some new liberties and lost |
| 3621 | * a neighbor. For speed reasons we handle two most common cases |
| 3622 | * when string size is 1 or 2 stones here instead of calling |
| 3623 | * update_liberties(). |
| 3624 | */ |
| 3625 | if (size == 1) { |
| 3626 | for (k = 0; k < string[s].neighbors; k++) { |
| 3627 | int neighbor = string_neighbors[s].list[k]; |
| 3628 | |
| 3629 | remove_neighbor(neighbor, s); |
| 3630 | PUSH_VALUE(string[neighbor].liberties); |
| 3631 | |
| 3632 | if (string[neighbor].liberties < MAX_LIBERTIES) |
| 3633 | string_libs[neighbor].list[string[neighbor].liberties] = pos; |
| 3634 | string[neighbor].liberties++; |
| 3635 | } |
| 3636 | } |
| 3637 | else if (size == 2) { |
| 3638 | int other = OTHER_COLOR(string[s].color); |
| 3639 | int pos2 = NEXT_STONE(pos); |
| 3640 | |
| 3641 | for (k = 0; k < string[s].neighbors; k++) { |
| 3642 | int neighbor = string_neighbors[s].list[k]; |
| 3643 | |
| 3644 | remove_neighbor(neighbor, s); |
| 3645 | PUSH_VALUE(string[neighbor].liberties); |
| 3646 | |
| 3647 | if (NEIGHBOR_OF_STRING(pos, neighbor, other)) { |
| 3648 | if (string[neighbor].liberties < MAX_LIBERTIES) |
| 3649 | string_libs[neighbor].list[string[neighbor].liberties] = pos; |
| 3650 | string[neighbor].liberties++; |
| 3651 | } |
| 3652 | |
| 3653 | if (NEIGHBOR_OF_STRING(pos2, neighbor, other)) { |
| 3654 | if (string[neighbor].liberties < MAX_LIBERTIES) |
| 3655 | string_libs[neighbor].list[string[neighbor].liberties] = pos2; |
| 3656 | string[neighbor].liberties++; |
| 3657 | } |
| 3658 | } |
| 3659 | } |
| 3660 | else { |
| 3661 | for (k = 0; k < string[s].neighbors; k++) { |
| 3662 | remove_neighbor(string_neighbors[s].list[k], s); |
| 3663 | update_liberties(string_neighbors[s].list[k]); |
| 3664 | } |
| 3665 | } |
| 3666 | |
| 3667 | /* Update the number of captured stones. These are assumed to |
| 3668 | * already have been pushed. |
| 3669 | */ |
| 3670 | if (string[s].color == WHITE) |
| 3671 | white_captured += size; |
| 3672 | else |
| 3673 | black_captured += size; |
| 3674 | |
| 3675 | return size; |
| 3676 | } |
| 3677 | |
| 3678 | |
| 3679 | /* We have played an isolated new stone and need to create a new |
| 3680 | * string for it. |
| 3681 | */ |
| 3682 | static void |
| 3683 | create_new_string(int pos) |
| 3684 | { |
| 3685 | int s; |
| 3686 | int color = board[pos]; |
| 3687 | int other = OTHER_COLOR(color); |
| 3688 | |
| 3689 | /* Get the next free string number. */ |
| 3690 | PUSH_VALUE(next_string); |
| 3691 | s = next_string++; |
| 3692 | PARANOID1(s < MAX_STRINGS, pos); |
| 3693 | string_number[pos] = s; |
| 3694 | /* Set up a size one cycle for the string. */ |
| 3695 | next_stone[pos] = pos; |
| 3696 | |
| 3697 | /* Set trivially known values and initialize the rest to zero. */ |
| 3698 | string[s].color = color; |
| 3699 | string[s].size = 1; |
| 3700 | string[s].origin = pos; |
| 3701 | string[s].liberties = 0; |
| 3702 | string[s].neighbors = 0; |
| 3703 | string[s].mark = 0; |
| 3704 | |
| 3705 | /* Clear the string mark. */ |
| 3706 | string_mark++; |
| 3707 | |
| 3708 | /* In each direction, look for a liberty or a nonmarked opponent |
| 3709 | * neighbor. Mark visited neighbors. There is no need to mark the |
| 3710 | * liberties since we can't find them twice. */ |
| 3711 | if (LIBERTY(SOUTH(pos))) { |
| 3712 | ADD_LIBERTY(s, SOUTH(pos)); |
| 3713 | } |
| 3714 | else if (UNMARKED_COLOR_STRING(SOUTH(pos), other)) { |
| 3715 | int s2 = string_number[SOUTH(pos)]; |
| 3716 | /* Add the neighbor to our list. */ |
| 3717 | ADD_NEIGHBOR(s, SOUTH(pos)); |
| 3718 | /* Add us to our neighbor's list. */ |
| 3719 | PUSH_VALUE(string[s2].neighbors); |
| 3720 | ADD_NEIGHBOR(s2, pos); |
| 3721 | MARK_STRING(SOUTH(pos)); |
| 3722 | } |
| 3723 | |
| 3724 | if (LIBERTY(WEST(pos))) { |
| 3725 | ADD_LIBERTY(s, WEST(pos)); |
| 3726 | } |
| 3727 | else if (UNMARKED_COLOR_STRING(WEST(pos), other)) { |
| 3728 | int s2 = string_number[WEST(pos)]; |
| 3729 | /* Add the neighbor to our list. */ |
| 3730 | ADD_NEIGHBOR(s, WEST(pos)); |
| 3731 | /* Add us to our neighbor's list. */ |
| 3732 | PUSH_VALUE(string[s2].neighbors); |
| 3733 | ADD_NEIGHBOR(s2, pos); |
| 3734 | MARK_STRING(WEST(pos)); |
| 3735 | } |
| 3736 | |
| 3737 | if (LIBERTY(NORTH(pos))) { |
| 3738 | ADD_LIBERTY(s, NORTH(pos)); |
| 3739 | } |
| 3740 | else if (UNMARKED_COLOR_STRING(NORTH(pos), other)) { |
| 3741 | int s2 = string_number[NORTH(pos)]; |
| 3742 | /* Add the neighbor to our list. */ |
| 3743 | ADD_NEIGHBOR(s, NORTH(pos)); |
| 3744 | /* Add us to our neighbor's list. */ |
| 3745 | PUSH_VALUE(string[s2].neighbors); |
| 3746 | ADD_NEIGHBOR(s2, pos); |
| 3747 | MARK_STRING(NORTH(pos)); |
| 3748 | } |
| 3749 | |
| 3750 | if (LIBERTY(EAST(pos))) { |
| 3751 | ADD_LIBERTY(s, EAST(pos)); |
| 3752 | } |
| 3753 | else if (UNMARKED_COLOR_STRING(EAST(pos), other)) { |
| 3754 | int s2 = string_number[EAST(pos)]; |
| 3755 | /* Add the neighbor to our list. */ |
| 3756 | ADD_NEIGHBOR(s, EAST(pos)); |
| 3757 | /* Add us to our neighbor's list. */ |
| 3758 | PUSH_VALUE(string[s2].neighbors); |
| 3759 | ADD_NEIGHBOR(s2, pos); |
| 3760 | /* No need to mark since no visits left. */ |
| 3761 | #if 0 |
| 3762 | MARK_STRING(EAST(pos)); |
| 3763 | #endif |
| 3764 | } |
| 3765 | } |
| 3766 | |
| 3767 | |
| 3768 | /* We have played a stone with exactly one friendly neighbor. Add the |
| 3769 | * new stone to that string. |
| 3770 | */ |
| 3771 | static void |
| 3772 | extend_neighbor_string(int pos, int s) |
| 3773 | { |
| 3774 | int k; |
| 3775 | int liberties_updated = 0; |
| 3776 | int color = board[pos]; |
| 3777 | int other = OTHER_COLOR(color); |
| 3778 | |
| 3779 | /* Link in the stone in the cyclic list. */ |
| 3780 | int pos2 = string[s].origin; |
| 3781 | next_stone[pos] = next_stone[pos2]; |
| 3782 | PUSH_VALUE(next_stone[pos2]); |
| 3783 | next_stone[pos2] = pos; |
| 3784 | |
| 3785 | /* Do we need to update the origin? */ |
| 3786 | if (pos < pos2) { |
| 3787 | PUSH_VALUE(string[s].origin); |
| 3788 | string[s].origin = pos; |
| 3789 | } |
| 3790 | |
| 3791 | string_number[pos] = s; |
| 3792 | |
| 3793 | /* The size of the string has increased by one. */ |
| 3794 | PUSH_VALUE(string[s].size); |
| 3795 | string[s].size++; |
| 3796 | |
| 3797 | /* If s has too many liberties, we don't know where they all are and |
| 3798 | * can't update the liberties with the algorithm we otherwise |
| 3799 | * use. In that case we can only recompute the liberties from |
| 3800 | * scratch. |
| 3801 | */ |
| 3802 | if (string[s].liberties > MAX_LIBERTIES) { |
| 3803 | update_liberties(s); |
| 3804 | liberties_updated = 1; |
| 3805 | } |
| 3806 | else { |
| 3807 | /* The place of the new stone is no longer a liberty. */ |
| 3808 | remove_liberty(s, pos); |
| 3809 | } |
| 3810 | |
| 3811 | /* Mark old neighbors of the string. */ |
| 3812 | string_mark++; |
| 3813 | for (k = 0; k < string[s].neighbors; k++) |
| 3814 | string[string_neighbors[s].list[k]].mark = string_mark; |
| 3815 | |
| 3816 | /* Look at the neighbor locations of pos for new liberties and/or |
| 3817 | * neighbor strings. |
| 3818 | */ |
| 3819 | |
| 3820 | /* If we find a liberty, look two steps away to determine whether |
| 3821 | * this already is a liberty of s. |
| 3822 | */ |
| 3823 | if (LIBERTY(SOUTH(pos))) { |
| 3824 | if (!liberties_updated |
| 3825 | && !NON_SOUTH_NEIGHBOR_OF_STRING(SOUTH(pos), s, color)) |
| 3826 | ADD_LIBERTY(s, SOUTH(pos)); |
| 3827 | } |
| 3828 | else if (UNMARKED_COLOR_STRING(SOUTH(pos), other)) { |
| 3829 | int s2 = string_number[SOUTH(pos)]; |
| 3830 | PUSH_VALUE(string[s].neighbors); |
| 3831 | ADD_NEIGHBOR(s, SOUTH(pos)); |
| 3832 | PUSH_VALUE(string[s2].neighbors); |
| 3833 | ADD_NEIGHBOR(s2, pos); |
| 3834 | MARK_STRING(SOUTH(pos)); |
| 3835 | } |
| 3836 | |
| 3837 | if (LIBERTY(WEST(pos))) { |
| 3838 | if (!liberties_updated |
| 3839 | && !NON_WEST_NEIGHBOR_OF_STRING(WEST(pos), s, color)) |
| 3840 | ADD_LIBERTY(s, WEST(pos)); |
| 3841 | } |
| 3842 | else if (UNMARKED_COLOR_STRING(WEST(pos), other)) { |
| 3843 | int s2 = string_number[WEST(pos)]; |
| 3844 | PUSH_VALUE(string[s].neighbors); |
| 3845 | ADD_NEIGHBOR(s, WEST(pos)); |
| 3846 | PUSH_VALUE(string[s2].neighbors); |
| 3847 | ADD_NEIGHBOR(s2, pos); |
| 3848 | MARK_STRING(WEST(pos)); |
| 3849 | } |
| 3850 | |
| 3851 | if (LIBERTY(NORTH(pos))) { |
| 3852 | if (!liberties_updated |
| 3853 | && !NON_NORTH_NEIGHBOR_OF_STRING(NORTH(pos), s, color)) |
| 3854 | ADD_LIBERTY(s, NORTH(pos)); |
| 3855 | } |
| 3856 | else if (UNMARKED_COLOR_STRING(NORTH(pos), other)) { |
| 3857 | int s2 = string_number[NORTH(pos)]; |
| 3858 | PUSH_VALUE(string[s].neighbors); |
| 3859 | ADD_NEIGHBOR(s, NORTH(pos)); |
| 3860 | PUSH_VALUE(string[s2].neighbors); |
| 3861 | ADD_NEIGHBOR(s2, pos); |
| 3862 | MARK_STRING(NORTH(pos)); |
| 3863 | } |
| 3864 | |
| 3865 | if (LIBERTY(EAST(pos))) { |
| 3866 | if (!liberties_updated |
| 3867 | && !NON_EAST_NEIGHBOR_OF_STRING(EAST(pos), s, color)) |
| 3868 | ADD_LIBERTY(s, EAST(pos)); |
| 3869 | } |
| 3870 | else if (UNMARKED_COLOR_STRING(EAST(pos), other)) { |
| 3871 | int s2 = string_number[EAST(pos)]; |
| 3872 | PUSH_VALUE(string[s].neighbors); |
| 3873 | ADD_NEIGHBOR(s, EAST(pos)); |
| 3874 | PUSH_VALUE(string[s2].neighbors); |
| 3875 | ADD_NEIGHBOR(s2, pos); |
| 3876 | #if 0 |
| 3877 | MARK_STRING(EAST(pos)); |
| 3878 | #endif |
| 3879 | } |
| 3880 | |
| 3881 | } |
| 3882 | |
| 3883 | |
| 3884 | /* Incorporate the string at pos with the string s. |
| 3885 | */ |
| 3886 | |
| 3887 | static void |
| 3888 | assimilate_string(int s, int pos) |
| 3889 | { |
| 3890 | int k; |
| 3891 | int last; |
| 3892 | int s2 = string_number[pos]; |
| 3893 | string[s].size += string[s2].size; |
| 3894 | |
| 3895 | /* Walk through the s2 stones and change string number. Also pick up |
| 3896 | * the last stone in the cycle for later use. |
| 3897 | */ |
| 3898 | pos = FIRST_STONE(s2); |
| 3899 | do { |
| 3900 | PUSH_VALUE(string_number[pos]); |
| 3901 | string_number[pos] = s; |
| 3902 | last = pos; |
| 3903 | pos = NEXT_STONE(pos); |
| 3904 | } while (!BACK_TO_FIRST_STONE(s2, pos)); |
| 3905 | |
| 3906 | /* Link the two cycles together. */ |
| 3907 | { |
| 3908 | int pos2 = string[s].origin; |
| 3909 | PUSH_VALUE(next_stone[last]); |
| 3910 | PUSH_VALUE(next_stone[pos2]); |
| 3911 | next_stone[last] = next_stone[pos2]; |
| 3912 | next_stone[pos2] = string[s2].origin; |
| 3913 | |
| 3914 | /* Do we need to update the origin? */ |
| 3915 | if (string[s2].origin < pos2) |
| 3916 | string[s].origin = string[s2].origin; |
| 3917 | } |
| 3918 | |
| 3919 | /* Pick up the liberties of s2 that we don't already have. |
| 3920 | * It is assumed that the liberties of s have been marked before |
| 3921 | * this function is called. |
| 3922 | */ |
| 3923 | if (string[s2].liberties <= MAX_LIBERTIES) { |
| 3924 | for (k = 0; k < string[s2].liberties; k++) { |
| 3925 | int pos2 = string_libs[s2].list[k]; |
| 3926 | if (UNMARKED_LIBERTY(pos2)) { |
| 3927 | ADD_AND_MARK_LIBERTY(s, pos2); |
| 3928 | } |
| 3929 | } |
| 3930 | } |
| 3931 | else { |
| 3932 | /* If s2 had too many liberties the above strategy wouldn't be |
| 3933 | * effective, since not all liberties are listed in |
| 3934 | * libs[] the chain of stones for s2 is no |
| 3935 | * longer available (it has already been merged with s) so we |
| 3936 | * can't reconstruct the s2 liberties. Instead we capitulate and |
| 3937 | * rebuild the list of liberties for s (including the neighbor |
| 3938 | * strings assimilated so far) from scratch. |
| 3939 | */ |
| 3940 | liberty_mark++; /* Reset the mark. */ |
| 3941 | string[s].liberties = 0; /* To avoid pushing the current list. */ |
| 3942 | update_liberties(s); |
| 3943 | } |
| 3944 | |
| 3945 | /* Remove s2 as neighbor to the neighbors of s2 and instead add s if |
| 3946 | * they don't already have added it. Also add the neighbors of s2 as |
| 3947 | * neighbors of s, unless they already have been added. The already |
| 3948 | * known neighbors of s are assumed to have been marked before this |
| 3949 | * function is called. |
| 3950 | */ |
| 3951 | for (k = 0; k < string[s2].neighbors; k++) { |
| 3952 | int t = string_neighbors[s2].list[k]; |
| 3953 | remove_neighbor(t, s2); |
| 3954 | if (string[t].mark != string_mark) { |
| 3955 | PUSH_VALUE(string[t].neighbors); |
| 3956 | string_neighbors[t].list[string[t].neighbors++] = s; |
| 3957 | string_neighbors[s].list[string[s].neighbors++] = t; |
| 3958 | string[t].mark = string_mark; |
| 3959 | } |
| 3960 | } |
| 3961 | } |
| 3962 | |
| 3963 | |
| 3964 | /* Create a new string for the stone at pos and assimilate all |
| 3965 | * friendly neighbor strings. |
| 3966 | */ |
| 3967 | |
| 3968 | static void |
| 3969 | assimilate_neighbor_strings(int pos) |
| 3970 | { |
| 3971 | int s; |
| 3972 | int color = board[pos]; |
| 3973 | int other = OTHER_COLOR(color); |
| 3974 | |
| 3975 | /* Get the next free string number. */ |
| 3976 | PUSH_VALUE(next_string); |
| 3977 | s = next_string++; |
| 3978 | PARANOID1(s < MAX_STRINGS, pos); |
| 3979 | string_number[pos] = s; |
| 3980 | /* Set up a size one cycle for the string. */ |
| 3981 | next_stone[pos] = pos; |
| 3982 | |
| 3983 | /* Set trivially known values and initialize the rest to zero. */ |
| 3984 | string[s].color = color; |
| 3985 | string[s].size = 1; |
| 3986 | string[s].origin = pos; |
| 3987 | string[s].liberties = 0; |
| 3988 | string[s].neighbors = 0; |
| 3989 | |
| 3990 | /* Clear the marks. */ |
| 3991 | liberty_mark++; |
| 3992 | string_mark++; |
| 3993 | |
| 3994 | /* Mark ourselves. */ |
| 3995 | string[s].mark = string_mark; |
| 3996 | |
| 3997 | /* Look in each direction for |
| 3998 | * |
| 3999 | * 1. liberty: Add if not already visited. |
| 4000 | * 2. opponent string: Add it among our neighbors and us among its |
| 4001 | * neighbors, unless already visited. |
| 4002 | * 3. friendly string: Assimilate. |
| 4003 | */ |
| 4004 | if (UNMARKED_LIBERTY(SOUTH(pos))) { |
| 4005 | ADD_AND_MARK_LIBERTY(s, SOUTH(pos)); |
| 4006 | } |
| 4007 | else if (UNMARKED_COLOR_STRING(SOUTH(pos), other)) { |
| 4008 | ADD_NEIGHBOR(s, SOUTH(pos)); |
| 4009 | PUSH_VALUE(string[string_number[SOUTH(pos)]].neighbors); |
| 4010 | ADD_NEIGHBOR(string_number[SOUTH(pos)], pos); |
| 4011 | MARK_STRING(SOUTH(pos)); |
| 4012 | } |
| 4013 | else if (UNMARKED_COLOR_STRING(SOUTH(pos), color)) { |
| 4014 | assimilate_string(s, SOUTH(pos)); |
| 4015 | } |
| 4016 | |
| 4017 | if (UNMARKED_LIBERTY(WEST(pos))) { |
| 4018 | ADD_AND_MARK_LIBERTY(s, WEST(pos)); |
| 4019 | } |
| 4020 | else if (UNMARKED_COLOR_STRING(WEST(pos), other)) { |
| 4021 | ADD_NEIGHBOR(s, WEST(pos)); |
| 4022 | PUSH_VALUE(string[string_number[WEST(pos)]].neighbors); |
| 4023 | ADD_NEIGHBOR(string_number[WEST(pos)], pos); |
| 4024 | MARK_STRING(WEST(pos)); |
| 4025 | } |
| 4026 | else if (UNMARKED_COLOR_STRING(WEST(pos), color)) { |
| 4027 | assimilate_string(s, WEST(pos)); |
| 4028 | } |
| 4029 | |
| 4030 | if (UNMARKED_LIBERTY(NORTH(pos))) { |
| 4031 | ADD_AND_MARK_LIBERTY(s, NORTH(pos)); |
| 4032 | } |
| 4033 | else if (UNMARKED_COLOR_STRING(NORTH(pos), other)) { |
| 4034 | ADD_NEIGHBOR(s, NORTH(pos)); |
| 4035 | PUSH_VALUE(string[string_number[NORTH(pos)]].neighbors); |
| 4036 | ADD_NEIGHBOR(string_number[NORTH(pos)], pos); |
| 4037 | MARK_STRING(NORTH(pos)); |
| 4038 | } |
| 4039 | else if (UNMARKED_COLOR_STRING(NORTH(pos), color)) { |
| 4040 | assimilate_string(s, NORTH(pos)); |
| 4041 | } |
| 4042 | |
| 4043 | if (UNMARKED_LIBERTY(EAST(pos))) { |
| 4044 | #if 0 |
| 4045 | ADD_AND_MARK_LIBERTY(s, EAST(pos)); |
| 4046 | #else |
| 4047 | ADD_LIBERTY(s, EAST(pos)); |
| 4048 | #endif |
| 4049 | } |
| 4050 | else if (UNMARKED_COLOR_STRING(EAST(pos), other)) { |
| 4051 | ADD_NEIGHBOR(s, EAST(pos)); |
| 4052 | PUSH_VALUE(string[string_number[EAST(pos)]].neighbors); |
| 4053 | ADD_NEIGHBOR(string_number[EAST(pos)], pos); |
| 4054 | #if 0 |
| 4055 | MARK_STRING(EAST(pos)); |
| 4056 | #endif |
| 4057 | } |
| 4058 | else if (UNMARKED_COLOR_STRING(EAST(pos), color)) { |
| 4059 | assimilate_string(s, EAST(pos)); |
| 4060 | } |
| 4061 | } |
| 4062 | |
| 4063 | |
| 4064 | /* Suicide at `pos' (the function assumes that the move is indeed suicidal). |
| 4065 | * Remove the neighboring friendly strings. |
| 4066 | */ |
| 4067 | |
| 4068 | static void |
| 4069 | do_commit_suicide(int pos, int color) |
| 4070 | { |
| 4071 | if (board[SOUTH(pos)] == color) |
| 4072 | do_remove_string(string_number[SOUTH(pos)]); |
| 4073 | |
| 4074 | if (board[WEST(pos)] == color) |
| 4075 | do_remove_string(string_number[WEST(pos)]); |
| 4076 | |
| 4077 | if (board[NORTH(pos)] == color) |
| 4078 | do_remove_string(string_number[NORTH(pos)]); |
| 4079 | |
| 4080 | if (board[EAST(pos)] == color) |
| 4081 | do_remove_string(string_number[EAST(pos)]); |
| 4082 | |
| 4083 | /* Count the stone we "played" as captured. */ |
| 4084 | if (color == WHITE) |
| 4085 | white_captured++; |
| 4086 | else |
| 4087 | black_captured++; |
| 4088 | } |
| 4089 | |
| 4090 | |
| 4091 | /* Play a move without legality checking. This is a low-level function, |
| 4092 | * it assumes that the move is not a suicide. Such cases must be handled |
| 4093 | * where the function is called. |
| 4094 | */ |
| 4095 | |
| 4096 | static void |
| 4097 | do_play_move(int pos, int color) |
| 4098 | { |
| 4099 | int other = OTHER_COLOR(color); |
| 4100 | int captured_stones = 0; |
| 4101 | int neighbor_allies = 0; |
| 4102 | int s = -1; |
| 4103 | |
| 4104 | /* Clear string mark. */ |
| 4105 | string_mark++; |
| 4106 | |
| 4107 | /* Put down the stone. We also set its string number to -1 for a while |
| 4108 | * so that NEIGHBOR_OF_STRING() and friends don't get confused with the |
| 4109 | * stone. |
| 4110 | */ |
| 4111 | DO_ADD_STONE(pos, color); |
| 4112 | string_number[pos] = -1; |
| 4113 | |
| 4114 | /* Look in all directions. Count the number of neighbor strings of the same |
| 4115 | * color, remove captured strings and remove `pos' as liberty for opponent |
| 4116 | * strings that are not captured. |
| 4117 | */ |
| 4118 | if (board[SOUTH(pos)] == color) { |
| 4119 | neighbor_allies++; |
| 4120 | s = string_number[SOUTH(pos)]; |
| 4121 | MARK_STRING(SOUTH(pos)); |
| 4122 | } |
| 4123 | else if (board[SOUTH(pos)] == other) { |
| 4124 | if (LIBERTIES(SOUTH(pos)) > 1) { |
| 4125 | remove_liberty(string_number[SOUTH(pos)], pos); |
| 4126 | MARK_STRING(SOUTH(pos)); |
| 4127 | } |
| 4128 | else |
| 4129 | captured_stones += do_remove_string(string_number[SOUTH(pos)]); |
| 4130 | } |
| 4131 | |
| 4132 | if (UNMARKED_COLOR_STRING(WEST(pos), color)) { |
| 4133 | neighbor_allies++; |
| 4134 | s = string_number[WEST(pos)]; |
| 4135 | MARK_STRING(WEST(pos)); |
| 4136 | } |
| 4137 | else if (UNMARKED_COLOR_STRING(WEST(pos), other)) { |
| 4138 | if (LIBERTIES(WEST(pos)) > 1) { |
| 4139 | remove_liberty(string_number[WEST(pos)], pos); |
| 4140 | MARK_STRING(WEST(pos)); |
| 4141 | } |
| 4142 | else |
| 4143 | captured_stones += do_remove_string(string_number[WEST(pos)]); |
| 4144 | } |
| 4145 | |
| 4146 | if (UNMARKED_COLOR_STRING(NORTH(pos), color)) { |
| 4147 | neighbor_allies++; |
| 4148 | s = string_number[NORTH(pos)]; |
| 4149 | MARK_STRING(NORTH(pos)); |
| 4150 | } |
| 4151 | else if (UNMARKED_COLOR_STRING(NORTH(pos), other)) { |
| 4152 | if (LIBERTIES(NORTH(pos)) > 1) { |
| 4153 | remove_liberty(string_number[NORTH(pos)], pos); |
| 4154 | MARK_STRING(NORTH(pos)); |
| 4155 | } |
| 4156 | else |
| 4157 | captured_stones += do_remove_string(string_number[NORTH(pos)]); |
| 4158 | } |
| 4159 | |
| 4160 | if (UNMARKED_COLOR_STRING(EAST(pos), color)) { |
| 4161 | neighbor_allies++; |
| 4162 | s = string_number[EAST(pos)]; |
| 4163 | #if 0 |
| 4164 | MARK_STRING(EAST(pos)); |
| 4165 | #endif |
| 4166 | } |
| 4167 | else if (UNMARKED_COLOR_STRING(EAST(pos), other)) { |
| 4168 | if (LIBERTIES(EAST(pos)) > 1) { |
| 4169 | remove_liberty(string_number[EAST(pos)], pos); |
| 4170 | #if 0 |
| 4171 | MARK_STRING(EAST(pos)); |
| 4172 | #endif |
| 4173 | } |
| 4174 | else |
| 4175 | captured_stones += do_remove_string(string_number[EAST(pos)]); |
| 4176 | } |
| 4177 | |
| 4178 | /* Choose strategy depending on the number of friendly neighbors. */ |
| 4179 | if (neighbor_allies == 0) |
| 4180 | create_new_string(pos); |
| 4181 | else if (neighbor_allies == 1) { |
| 4182 | gg_assert(s >= 0); |
| 4183 | extend_neighbor_string(pos, s); |
| 4184 | return; /* can't be a ko, we're done */ |
| 4185 | } |
| 4186 | else { |
| 4187 | assimilate_neighbor_strings(pos); |
| 4188 | return; /* can't be a ko, we're done */ |
| 4189 | } |
| 4190 | |
| 4191 | /* Check whether this move was a ko capture and if so set |
| 4192 | * board_ko_pos. |
| 4193 | * |
| 4194 | * No need to push board_ko_pos on the stack, |
| 4195 | * because this has been done earlier. |
| 4196 | */ |
| 4197 | s = string_number[pos]; |
| 4198 | if (string[s].liberties == 1 |
| 4199 | && string[s].size == 1 |
| 4200 | && captured_stones == 1) { |
| 4201 | /* In case of a double ko: clear old ko position first. */ |
| 4202 | if (board_ko_pos != NO_MOVE) |
| 4203 | hashdata_invert_ko(&board_hash, board_ko_pos); |
| 4204 | board_ko_pos = string_libs[s].list[0]; |
| 4205 | hashdata_invert_ko(&board_hash, board_ko_pos); |
| 4206 | } |
| 4207 | } |
| 4208 | |
| 4209 | |
| 4210 | |
| 4211 | /* ================================================================ * |
| 4212 | * The following functions don't actually belong here. They are |
| 4213 | * only here because they are faster here where they have access to |
| 4214 | * the incremental data structures. |
| 4215 | * ================================================================ */ |
| 4216 | |
| 4217 | |
| 4218 | /* Help collect the data needed by order_moves() in reading.c. |
| 4219 | * It's the caller's responsibility to initialize the result parameters. |
| 4220 | */ |
| 4221 | #define NO_UNROLL 0 |
| 4222 | void |
| 4223 | incremental_order_moves(int move, int color, int str, |
| 4224 | int *number_edges, int *number_same_string, |
| 4225 | int *number_own, int *number_opponent, |
| 4226 | int *captured_stones, int *threatened_stones, |
| 4227 | int *saved_stones, int *number_open) |
| 4228 | { |
| 4229 | #if NO_UNROLL == 1 |
| 4230 | int pos; |
| 4231 | int k; |
| 4232 | |
| 4233 | /* Clear the string mark. */ |
| 4234 | string_mark++; |
| 4235 | |
| 4236 | for (k = 0; k < 4; k++) { |
| 4237 | pos = move + delta[k]; |
| 4238 | if (!ON_BOARD(pos)) |
| 4239 | (*number_edges)++; |
| 4240 | else if (board[pos] == EMPTY) |
| 4241 | (*number_open)++; |
| 4242 | else { |
| 4243 | int s = string_number[pos]; |
| 4244 | if (string_number[str] == s) |
| 4245 | (*number_same_string)++; |
| 4246 | |
| 4247 | if (board[pos] == color) { |
| 4248 | (*number_own)++; |
| 4249 | if (string[s].liberties == 1) |
| 4250 | (*saved_stones) += string[s].size; |
| 4251 | } |
| 4252 | else { |
| 4253 | (*number_opponent)++; |
| 4254 | if (string[s].liberties == 1) { |
| 4255 | int r; |
| 4256 | struct string_data *t; |
| 4257 | (*captured_stones) += string[s].size; |
| 4258 | for (r = 0; r < string[s].neighbors; r++) { |
| 4259 | t = &string[string[s].neighborlist[r]]; |
| 4260 | if (t->liberties == 1) |
| 4261 | (*saved_stones) += t->size; |
| 4262 | } |
| 4263 | } |
| 4264 | else if (string[s].liberties == 2 && UNMARKED_STRING(pos)) { |
| 4265 | (*threatened_stones) += string[s].size; |
| 4266 | MARK_STRING(pos); |
| 4267 | } |
| 4268 | } |
| 4269 | } |
| 4270 | } |
| 4271 | |
| 4272 | #else |
| 4273 | #define code1(arg) \ |
| 4274 | if (!ON_BOARD(arg)) \ |
| 4275 | (*number_edges)++; \ |
| 4276 | else if (board[arg] == EMPTY) \ |
| 4277 | (*number_open)++; \ |
| 4278 | else { \ |
| 4279 | int s = string_number[arg]; \ |
| 4280 | if (string_number[str] == s) \ |
| 4281 | (*number_same_string)++; \ |
| 4282 | if (board[arg] == color) { \ |
| 4283 | (*number_own)++; \ |
| 4284 | if (string[s].liberties == 1) \ |
| 4285 | (*saved_stones) += string[s].size; \ |
| 4286 | } \ |
| 4287 | else { \ |
| 4288 | (*number_opponent)++; \ |
| 4289 | if (string[s].liberties == 1) { \ |
| 4290 | int r; \ |
| 4291 | struct string_data *t; \ |
| 4292 | (*captured_stones) += string[s].size; \ |
| 4293 | for (r = 0; r < string[s].neighbors; r++) { \ |
| 4294 | t = &string[string_neighbors[s].list[r]]; \ |
| 4295 | if (t->liberties == 1) \ |
| 4296 | (*saved_stones) += t->size; \ |
| 4297 | } \ |
| 4298 | } \ |
| 4299 | else if (string[s].liberties == 2 && UNMARKED_STRING(arg)) { \ |
| 4300 | (*threatened_stones) += string[s].size; \ |
| 4301 | MARK_STRING(arg); \ |
| 4302 | } \ |
| 4303 | } \ |
| 4304 | } |
| 4305 | |
| 4306 | /* Clear the string mark. */ |
| 4307 | string_mark++; |
| 4308 | |
| 4309 | code1(SOUTH(move)); |
| 4310 | code1(WEST(move)); |
| 4311 | code1(NORTH(move)); |
| 4312 | code1(EAST(move)); |
| 4313 | #endif |
| 4314 | } |
| 4315 | |
| 4316 | |
| 4317 | int |
| 4318 | square_dist(int pos1, int pos2) |
| 4319 | { |
| 4320 | int idist = I(pos1) - I(pos2); |
| 4321 | int jdist = J(pos1) - J(pos2); |
| 4322 | return idist*idist + jdist*jdist; |
| 4323 | } |
| 4324 | |
| 4325 | |
| 4326 | /* |
| 4327 | * Local Variables: |
| 4328 | * tab-width: 8 |
| 4329 | * c-basic-offset: 2 |
| 4330 | * End: |
| 4331 | */ |