gnushogi/pattern.c

   1 /*
   2  * FILE: pattern.c
   3  *
   4  * ----------------------------------------------------------------------
   5  * Copyright (c) 1993, 1994, 1995 Matthias Mutz
   6  * Copyright (c) 1999 Michael Vanier and the Free Software Foundation
   7  *
   8  * GNU SHOGI is based on GNU CHESS
   9  *
  10  * Copyright (c) 1988, 1989, 1990 John Stanback
  11  * Copyright (c) 1992 Free Software Foundation
  12  *
  13  * This file is part of GNU SHOGI.
  14  *
  15  * GNU Shogi is free software; you can redistribute it and/or modify it
  16  * under the terms of the GNU General Public License as published by the
  17  * Free Software Foundation; either version 1, or (at your option) any
  18  * later version.
  19  *
  20  * GNU Shogi is distributed in the hope that it will be useful, but WITHOUT
  21  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  22  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  23  * for more details.
  24  *
  25  * You should have received a copy of the GNU General Public License along
  26  * with GNU Shogi; see the file COPYING.  If not, write to the Free
  27  * Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  28  * ----------------------------------------------------------------------
  29  *
  30  */
  31
  32 #include "gnushogi.h"
  33 #include "pattern.h"
  34
  35 /* constants and pattern_data are generated by "pat2inc" */
  36 #include "pattern.inc"
  37
  38 struct Pattern_rec Pattern[MAX_PATTERN];
  39 struct OpeningSequence_rec OpeningSequence[MAX_OPENING_SEQUENCE];
  40
  41 small_short pattern_data[MAX_PATTERN_DATA];
  42
  43
  44 short
  45 ValueOfOpeningName (char *name)
  46 {
  47     short i;
  48     i = (name[0] == 'C') ? 0 : 100;
  49
  50     switch (name[7])
  51     {
  52     case 'S':
  53         i += 10;
  54         break;
  55
  56     case 'R':
  57         i += 20;
  58         break;
  59
  60     case 'U':
  61         i += 30;
  62         break;
  63
  64     default:
  65         i += 40;
  66         break;
  67     }
  68
  69     switch (name[9])
  70     {
  71     case 'S':
  72         i += 1;
  73         break;
  74
  75     case 'R':
  76         i += 2;
  77         break;
  78
  79     case 'U':
  80         i += 3;
  81         break;
  82
  83     default:
  84         i += 4;
  85         break;
  86     }
  87
  88     return i;
  89 }
  90
  91
  92 void
  93 NameOfOpeningValue (short i, char *name)
  94 {
  95     if (i < 100)
  96     {
  97         strcpy(name, "CASTLE_?_?");
  98     }
  99     else
 100     {
 101         strcpy(name, "ATTACK_?_?");
 102         i -= 100;
 103     }
 104
 105     switch (i / 10)
 106     {
 107     case 1:
 108         name[7] = 'S';
 109         break;
 110
 111     case 2:
 112         name[7] = 'R';
 113         break;
 114
 115     case 3:
 116         name[7] = 'U';
 117         break;
 118
 119     default:
 120         name[7] = '*';
 121         break;
 122     }
 123
 124     switch (i % 10)
 125     {
 126     case 1:
 127         name[9] = 'S';
 128         break;
 129
 130     case 2:
 131         name[9] = 'R';
 132         break;
 133
 134     case 3:
 135         name[9] = 'U';
 136         break;
 137
 138     default:
 139         name[9] = '*';
 140         break;
 141     }
 142 }
 143
 144
 145 void
 146 GetOpeningPatterns (short *max_opening_sequence)
 147 {
 148     short pindex = 0;
 149     short os = 0;
 150     short p = 0;
 151     short i;
 152
 153     do
 154     {
 155         OpeningSequence[os].opening_type = pattern_data[pindex++];
 156         OpeningSequence[os].first_pattern[0] = p;
 157
 158         for (i = 1; i < MAX_SEQUENCE; i++)
 159             OpeningSequence[os].first_pattern[i] = END_OF_PATTERNS;
 160
 161         do
 162         {
 163             Pattern[p].reachedGameCnt[black] = MAXMOVES;
 164             Pattern[p].reachedGameCnt[white] = MAXMOVES;
 165             Pattern[p].first_link = pindex;
 166
 167             while (pattern_data[pindex] != END_OF_LINKS)
 168                 pindex++;
 169             pindex++;
 170
 171             Pattern[p].first_field = pindex;
 172
 173             while (pattern_data[pindex] != END_OF_FIELDS)
 174                 pindex += 2;
 175             pindex++;
 176
 177             if (pattern_data[pindex] != END_OF_PATTERNS)
 178                 Pattern[p].next_pattern = p + 1;
 179             else
 180                 Pattern[p].next_pattern = END_OF_PATTERNS;
 181
 182             p++;
 183         }
 184         while (pattern_data[pindex] != END_OF_PATTERNS);
 185
 186         pindex++;
 187         os++;
 188     }
 189     while (pattern_data[pindex] != END_OF_SEQUENCES);
 190
 191     *max_opening_sequence = os;
 192 }
 193
 194
 195
 196 void
 197 ShowOpeningPatterns (short max_opening_sequence)
 198
 199 {
 200     short os, p, n, i;
 201
 202     for (os = 0; os < max_opening_sequence; os++)
 203     {
 204         char name[16];
 205         NameOfOpeningValue(OpeningSequence[os].opening_type, name);
 206         printf("Opening Type: %s\n", name);
 207
 208         for (p = OpeningSequence[os].first_pattern[0], n = 0;
 209              p != END_OF_PATTERNS;
 210              p = Pattern[p].next_pattern, n++)
 211         {
 212             printf("Pattern %d (%d) with links ", p, n);
 213
 214             for (i = Pattern[p].first_link;
 215                  pattern_data[i] != END_OF_LINKS;
 216                  i++)
 217             {
 218                 printf("%d ", pattern_data[i]);
 219             }
 220
 221             printf("\n");
 222             DisplayPattern(stdout, Pattern[p].first_field);
 223         }
 224     }
 225 }
 226
 227
 228
 229 void
 230 set_field (short i, struct PatternField *field)
 231 {
 232     field->piece  = pattern_data[i];
 233     field->square = pattern_data[i+1];
 234
 235     if (field->square < 0)
 236     {
 237         field->square = -(field->square);
 238         field->side   = white;
 239     }
 240     else
 241     {
 242         field->side  = black;
 243     }
 244 }
 245
 246
 247
 248 /*
 249  * piece_to_pattern_distance (side, piece, pside, pattern)
 250  *
 251  * Determine the minimum number of moves from the current position to a
 252  * specific pattern for a specific piece.  Consider the "side" piece of the
 253  * pattern.  The pattern should match for "pside".
 254  */
 255
 256 short
 257 piece_to_pattern_distance(short side, short piece,
 258                           short pside, short pattern)
 259 {
 260     short nP, P[4], nB, B[4]; /* at most 4 pieces of same kind */
 261     short i, j, r, dd, occupied, mindd, c[4], d[4];
 262     /* a "side" patternfield must match a "c1" piece on board: */
 263     short c1 = side ^ pside;
 264
 265     /*
 266      * If pside == white, a black piece in the pattern should match a white
 267      * piece on board, and vice versa. Furthermore, if pside == white,
 268      * reversed pattern should match board.
 269      */
 270
 271     /* special pawn handling */
 272
 273     if (piece == pawn)
 274     {
 275         mindd = occupied = 0;
 276
 277         for (i = Pattern[pattern].first_field;
 278              pattern_data[i] != END_OF_FIELDS;
 279              i += 2)
 280         {
 281             struct PatternField field;
 282             set_field(i, &field);
 283
 284             if ((field.side == side) && (field.piece == pawn))
 285             {
 286                 short t = field.square;
 287                 short pcol = column(t);
 288                 dd = CANNOT_REACH;
 289
 290                 if (PawnCnt[c1][(side == c1) ? pcol : (8 - pcol)])
 291                 {
 292                     /* there is a pawn on the column */
 293                     for (j = 0; j <= PieceCnt[c1]; j++)
 294                     {
 295                         short sq = (short)PieceList[c1][j];
 296
 297                         if (board[sq] == pawn)
 298                         {
 299                             if (pside == white)
 300                                 sq = NO_SQUARES - 1 - sq;
 301
 302                             if (column(sq) == pcol)
 303                             {
 304                                 dd = piece_distance (side, pawn, sq, t);
 305 #ifdef TEST_PATTERN
 306                                 printf("update %d pawn "
 307                                        "from %d to %d is %d\n",
 308                                        side, sq, t, dd);
 309 #endif
 310                                 break;
 311                             }
 312                         }
 313                     }
 314                 }
 315                 else
 316                 {
 317                     /* there is no pawn on the column; drop possible? */
 318                     if (Captured[c1][pawn])
 319                     {
 320                         dd = 1;
 321 #ifdef TEST_PATTERN
 322                         printf("update %d pawn drop to %d is %d\n",
 323                                side, t, dd);
 324 #endif
 325                     }
 326                 }
 327
 328                 if (dd >= 0)
 329                 {
 330                     /* Increment distance if pattern field is occupied */
 331                     short psq, pc;
 332
 333                     if (pside == black)
 334                     {
 335                         psq = t;
 336                         pc = field.side;
 337                     }
 338                     else
 339                     {
 340                         psq = (NO_SQUARES - 1 - t);
 341                         pc = ~field.side;
 342                     }
 343
 344                     if ((color[psq] == pc) && (board[psq] != pawn))
 345                     {
 346 #ifdef TEST_PATTERN
 347                         printf("square %d is occupied\n", psq);
 348 #endif
 349                         ++occupied;
 350                     }
 351
 352                     mindd += dd;
 353                 }
 354                 else
 355                 {
 356                     return CANNOT_REACH;
 357                 }
 358             }
 359         }
 360
 361         return mindd + occupied;
 362     }
 363
 364     /*
 365      * Determine list of "side" "piece"s in pattern.
 366      */
 367
 368     for (occupied = nP = 0, i = Pattern[pattern].first_field;
 369          pattern_data[i] != END_OF_FIELDS;
 370          i += 2)
 371     {
 372         struct PatternField field;
 373         set_field(i, &field);
 374
 375         if ((field.side == side) && (field.piece == piece))
 376         {
 377             short psq, pc;
 378             P[nP] = field.square;
 379 #ifdef TEST_PATTERN
 380             printf("pattern %d piece %d on square %d\n", side, piece, P[nP]);
 381 #endif
 382             nP++;
 383
 384             /* Increment distance if pattern field is occupied */
 385             if (pside == black)
 386             {
 387                 psq = field.square;
 388                 pc = field.side;
 389             }
 390             else
 391             {
 392                 psq = NO_SQUARES - 1 - field.square;
 393                 pc  = field.side ^ 1;
 394             }
 395
 396             if ((color[psq] == pc) && (board[psq] != field.piece))
 397             {
 398 #ifdef TEST_PATTERN
 399                 printf("square %d is occupied\n", psq);
 400 #endif
 401                 ++occupied;
 402             }
 403         }
 404     }
 405
 406     if (nP == 0)
 407         return 0;
 408
 409 #ifdef TEST_PATTERN
 410     printf("finding in pattern %d pieces %d of side %d\n", nP, piece, side);
 411 #endif
 412
 413     /*
 414      * Determine list of "side ^ pside" "piece"s captured or on board.
 415      */
 416
 417     for (nB = 0; nB < Captured[c1][piece]; nB++)
 418         B[nB] = NO_SQUARES + piece;
 419
 420     for (i = 0; i <= PieceCnt[c1]; i++)
 421     {
 422         short sq = PieceList[c1][i];
 423
 424         if (board[sq] == piece)
 425         {
 426             B[nB] = (pside == black) ? sq : (NO_SQUARES - 1 - sq);
 427 #ifdef TEST_PATTERN
 428             printf("%d piece %d on square %d\n", side, piece, B[nB]);
 429 #endif
 430             nB++;
 431         }
 432     }
 433
 434 #ifdef TEST_PATTERN
 435     printf("found on board %d pieces %d of side %d\n", nB, piece, side);
 436 #endif
 437
 438     if (nP > nB)
 439     {
 440         return CANNOT_REACH;
 441     }
 442
 443     /* Determine best assignment from board piece to pattern piece */
 444
 445     r = 0;
 446     c[0] = -1;
 447     mindd = CANNOT_REACH;
 448
 449     while ((r >= 0) && (mindd != 0))
 450     {
 451
 452         if (++c[r] == nB)
 453         {
 454             r--;
 455         }
 456         else
 457         {
 458             for (i = 0; i < r; i++)
 459             {
 460                 if (c[i] == c[r])
 461                     break;
 462             }
 463
 464             if (i == r)
 465             {
 466                 d[r] =  piece_distance (side, piece, B[c[r]], P[r]);
 467 #ifdef TEST_PATTERN
 468                 printf("update d[%d] from  %d to %d is %d\n",
 469                        r, B[c[r]], P[r], d[r]);
 470 #endif
 471                 if (d[r] < 0)
 472                 {
 473                     /* r--; */
 474                 }
 475                 else
 476                 {
 477                     if (++r == nP)
 478                     {
 479                         for (dd = i = 0; i < nP; i++)
 480                             dd += d[i];
 481
 482                         if ((dd < mindd) || (mindd < 0))
 483                         {
 484                             mindd = dd;
 485 #ifdef TEST_PATTERN
 486                             printf("update min %d\n", mindd);
 487 #endif
 488                         }
 489
 490                         r--;
 491                     }
 492                     else
 493                     {
 494                         c[r] = -1;
 495                     }
 496                 }
 497             }
 498         }
 499     }
 500
 501     if (mindd < 0)
 502         return CANNOT_REACH;
 503     else
 504         return (mindd + occupied);
 505
 506 }
 507
 508
 509
 510 /*
 511  * pattern_distance (pside, pattern)
 512  *
 513  * Determine the minimum number of moves for the pieces from
 514  * the current position to reach a pattern.
 515  * The result is CANNOT_REACH, if there is no possible sequence
 516  * of moves.
 517  *
 518  */
 519
 520 short
 521 pattern_distance (short pside, short pattern)
 522 {
 523     short side, piece, d, n;
 524
 525 #ifdef TEST_PATTERN
 526     printf("\nchecking pattern %d for pside=%d\n\n", pattern, pside);
 527 #endif
 528
 529     for (n = side = 0; side <= 1 && n >= 0; side++)
 530     {
 531         for (piece = pawn; piece <= king; piece++)
 532         {
 533             d = piece_to_pattern_distance (side, piece, pside, pattern);
 534
 535             if (d < 0)
 536             {
 537                 n = CANNOT_REACH;
 538                 break;
 539             }
 540             else
 541             {
 542                 n += d;
 543             }
 544         }
 545     }
 546
 547 #ifdef TEST_PATTERN
 548     printf("\ndistance to pattern is %d\n\n", n);
 549 #endif
 550
 551     return n;
 552 }
 553
 554
 555
 556 /*
 557  * board_to_pattern_distance(pside, osequence, pmplty, GameCnt)
 558  *
 559  * Determine the maximal difference of the number of moves from the pattern
 560  * to the initial position and to the current position.
 561  * Differences are weighted, i.e. the more closer a position is to a pattern
 562  * the more valuable is a move towards the pattern.
 563  * Patterns, which are at least "pmplty" halfmoves away, are not counted.
 564  */
 565
 566 short
 567 board_to_pattern_distance
 568 (short pside, short osequence, short pmplty, short GameCnt)
 569 {
 570     short i, d, dist, diff, weighted_diff;
 571     short maxdiff = 0, max_weighted_diff = 0;
 572     short pattern;
 573
 574     for (i = 0; i < MAX_SEQUENCE; i++)
 575     {
 576         for (pattern = OpeningSequence[osequence].first_pattern[i];
 577              pattern != END_OF_PATTERNS;
 578              pattern = Pattern[pattern].next_pattern)
 579         {
 580             if ((d = Pattern[pattern].distance[pside]) >= 0)
 581             {
 582                 if (pmplty > d)
 583                 {
 584                     dist = pattern_distance (pside, pattern);
 585                     if (dist >= 0)
 586                     {
 587                         /*
 588                          * "dist" is the distance of the current board
 589                          * position to the pattern.  "d - dist" is the
 590                          * difference between the current distance and the
 591                          * initial distance. Compute "diff" as the weighted
 592                          * difference.
 593                          */
 594
 595                         /* try to reach the nearest pattern */
 596                         weighted_diff = (diff = (d - dist)) * (pmplty - d);
 597
 598                         if (weighted_diff > max_weighted_diff)
 599                         {
 600 #ifdef COUNT_DIFF
 601                             maxdiff = diff;
 602 #else
 603                             maxdiff = weighted_diff;
 604 #endif
 605                             max_weighted_diff = weighted_diff;
 606                         }
 607
 608                         /*
 609                          * A reached pattern should not be considered in
 610                          * the future (if GameCnt >= 0)
 611                          */
 612
 613                         if (dist == 0 && GameCnt >= 0)
 614                             Pattern[pattern].reachedGameCnt[pside] = GameCnt;
 615                     }
 616                 }
 617             }
 618         }
 619     }
 620
 621     return maxdiff;
 622 }
 623
 624
 625
 626
 627 void
 628 DisplayPattern (FILE *fd, short n)
 629 {
 630     small_short pboard[NO_SQUARES], pcolor[NO_SQUARES];
 631     short sq, i,  r, c;
 632
 633     for (sq = 0; sq < NO_SQUARES; sq++)
 634     {
 635         pboard[sq] = no_piece;
 636         pcolor[sq] = neutral;
 637     }
 638
 639     for (i = n; pattern_data[i] != END_OF_FIELDS; i += 2)
 640     {
 641         struct PatternField field;
 642         set_field(i, &field);
 643         pboard[field.square] = field.piece;
 644         pcolor[field.square] = field.side;
 645     }
 646
 647     for (r = NO_ROWS - 1; r >= 0; r--)
 648     {
 649         for (c = 0; c < NO_COLS; c++)
 650         {
 651             sq = r*NO_COLS + c;
 652             i = pboard[sq];
 653
 654             if (i == no_piece)
 655                 fprintf(fd, " -");
 656             else
 657                 fprintf(fd, "%c%c", is_promoted[i] ? '+' : ' ',
 658                         pcolor[sq] ? pxx[i] : qxx[i]);
 659         }
 660
 661         fprintf(fd, "\n");
 662     }
 663
 664     fprintf(fd, "\n");
 665 }
 666
 667
 668
 669
 670 static void
 671 VisitReachable (int pside, short osequence, int k, int n, int remove)
 672 {
 673     short i, j;
 674     short pattern;
 675
 676     /* Adjust to sequence pattern n */
 677     for (i = 0, pattern = OpeningSequence[osequence].first_pattern[k];
 678          i < n; i++)
 679     {
 680         pattern = Pattern[pattern].next_pattern;
 681     }
 682
 683     /* do not perform visited link twice */
 684     if (Pattern[pattern].visited)
 685     {
 686         return;
 687     }
 688     else
 689     {
 690         Pattern[pattern].visited = true;
 691     }
 692
 693     /* Declare links unreachable */
 694     for (j = Pattern[pattern].first_link;
 695          pattern_data[j] != END_OF_LINKS; j++)
 696     {
 697         VisitReachable(pside, osequence, k, pattern_data[j], remove);
 698     }
 699
 700     /* Declare unreachable */
 701     if (remove && Pattern[pattern].distance[pside] >= 0)
 702     {
 703         Pattern[pattern].distance[pside] = IS_SUCCESSOR;
 704     }
 705 }
 706
 707
 708 /* simplified matching for opening type names */
 709
 710 #define match_char(a, b) \
 711 (a == b || (a == '*' && b != 'U') || (b == '*' && a != 'U'))
 712
 713 #define match_name(a, b, l) \
 714 (l > 8 && match_char(a[0], b[0]) && match_char(a[7], b[7]) \
 715 && match_char(a[9], b[9]))
 716
 717
 718 short
 719 locate_opening_sequence(short pside, char *s, short GameCnt)
 720 {
 721     short i, j, k, os, d;
 722     short l = strlen(s);
 723     short check_visited[MAX_SEQUENCE];
 724     char name[MAX_NAME], name2[MAX_NAME];
 725
 726     /*
 727      * Look for opening pattern name in the list of opening patterns.
 728      */
 729
 730     name[0] = '\0';
 731
 732     for (i = 1, os = 0; os < MAX_OPENING_SEQUENCE; os++)
 733     {
 734         /* locate matching opening type name */
 735         NameOfOpeningValue(OpeningSequence[os].opening_type, name);
 736
 737         if (match_name(s, name, l))
 738         {
 739             /* locate successor matching names */
 740             for (k = os + 1; k < MAX_OPENING_SEQUENCE; k++)
 741             {
 742                 NameOfOpeningValue(OpeningSequence[k].opening_type, name2);
 743
 744                 if (match_name(s, name2, l))
 745                 {
 746                     OpeningSequence[os].first_pattern[i++]
 747                         = OpeningSequence[k].first_pattern[0];
 748                 }
 749             }
 750
 751             break;
 752         }
 753     }
 754
 755     if (os >= MAX_OPENING_SEQUENCE)
 756     {
 757         return END_OF_SEQUENCES;
 758     }
 759     else
 760     {
 761         for (; i < MAX_SEQUENCE;
 762              OpeningSequence[os].first_pattern[i++] = END_OF_PATTERNS);
 763     }
 764
 765     /*
 766      * Determine patterns which can be reached from the current
 767      * board position. Only patterns which can be reached will be
 768      * checked in the following search.
 769      */
 770
 771     for (i = 0; i < MAX_SEQUENCE; i++)
 772     {
 773         check_visited[i] = false;
 774
 775         for (k = OpeningSequence[os].first_pattern[i];
 776              k != END_OF_PATTERNS;
 777              k = Pattern[k].next_pattern)
 778         {
 779             Pattern[k].visited = false;
 780         }
 781     }
 782
 783     for (i = 0; i < MAX_SEQUENCE; i++)
 784     {
 785         for (k = OpeningSequence[os].first_pattern[i];
 786              k != END_OF_PATTERNS;
 787              k = Pattern[k].next_pattern)
 788         {
 789             Pattern[k].distance[pside] = pattern_distance(pside, k);
 790
 791             /* Actually reached patterns need not to be observed. */
 792             if (Pattern[k].distance[pside] == 0)
 793             {
 794                 Pattern[k].distance[pside] = CANNOT_REACH;
 795                 check_visited[i] = Pattern[k].visited = true;
 796
 797                 for (j = Pattern[k].first_link;
 798                      pattern_data[j] != END_OF_LINKS; j++)
 799                 {
 800                     VisitReachable(pside, os, i, pattern_data[j], false);
 801                 }
 802             }
 803             else if ((GameCnt >= 0)
 804                      && (GameCnt >= Pattern[k].reachedGameCnt[pside]))
 805             {
 806                 Pattern[k].distance[pside] = IS_REACHED;
 807             }
 808
 809             if (Pattern[k].reachedGameCnt[pside] >= GameCnt)
 810                 Pattern[k].reachedGameCnt[pside] = MAXMOVES;
 811         }
 812     }
 813
 814     /*
 815      * Remove reachable patterns from search, which are successors of
 816      * reachable patterns. So, only the next pattern of a pattern sequence
 817      * is observed.
 818      */
 819
 820     for (i = 0; i < MAX_SEQUENCE; i++)
 821     {
 822         for (k = OpeningSequence[os].first_pattern[i];
 823              k != END_OF_PATTERNS;
 824              k = Pattern[k].next_pattern)
 825         {
 826             if (check_visited[i] && !Pattern[k].visited)
 827                 Pattern[k].distance[pside] = NOT_TO_REACH;
 828             else
 829                 Pattern[k].visited = false;
 830         }
 831     }
 832
 833     for (i = 0; i < MAX_SEQUENCE; i++)
 834     {
 835         for (k = OpeningSequence[os].first_pattern[i];
 836              k != END_OF_PATTERNS;
 837              k = Pattern[k].next_pattern)
 838         {
 839             if ((d = Pattern[k].distance[pside]) >= 0)
 840             {
 841                 for (j = Pattern[k].first_link;
 842                      pattern_data[j] != END_OF_LINKS; j++)
 843                 {
 844                     VisitReachable(pside, os, i, pattern_data[j], true);
 845                 }
 846             }
 847         }
 848     }
 849
 850     /*
 851      * Look to see whether there is still a reachable pattern.
 852      */
 853
 854     for (i = 0; i < MAX_SEQUENCE; i++)
 855     {
 856         for (k = OpeningSequence[os].first_pattern[i];
 857              k != END_OF_PATTERNS;
 858              k = Pattern[k].next_pattern)
 859         {
 860             if ((d = Pattern[k].distance[pside]) >= 0)
 861                 return os;
 862         }
 863     }
 864
 865     return END_OF_SEQUENCES;
 866 }
 867
 868
 869
 870
 871 void
 872 update_advance_bonus (short pside, short os)
 873 {
 874     struct PatternField field;
 875     short i, j, k, d;
 876
 877     for (j = 0; j < MAX_SEQUENCE; j++)
 878     {
 879         for (k = OpeningSequence[os].first_pattern[j];
 880              k != END_OF_PATTERNS;
 881              k = Pattern[k].next_pattern)
 882         {
 883             if ((d = Pattern[k].distance[pside]) >= 0)
 884             {
 885                 for (i = Pattern[k].first_field;
 886                      pattern_data[i] != END_OF_FIELDS; i += 2)
 887                 {
 888                     set_field(i, &field);
 889                     if (field.side == black)
 890                     {
 891                         short square = (pside == black)
 892                             ? field.square
 893                             : NO_SQUARES - 1 - field.square;
 894
 895                         (*Mpiece[field.piece])[pside][square]
 896                             += ADVNCM[field.piece];
 897                     }
 898                 }
 899             }
 900         }
 901     }
 902 }