pattern.c

   1 #define DEBUG
   2 #include <assert.h>
   3 #include <ctype.h>
   4 #include <inttypes.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7
   8 #include "board.h"
   9 #include "debug.h"
  10 #include "pattern.h"
  11 #include "patternsp.h"
  12 #include "patternprob.h"
  13 #include "tactics/ladder.h"
  14 #include "tactics/selfatari.h"
  15 #include "tactics/util.h"
  16
  17 #define CAPTURE_COUNTSTONES_MAX ((1 << CAPTURE_COUNTSTONES_PAYLOAD_SIZE) - 1)
  18
  19
  20 struct pattern_config DEFAULT_PATTERN_CONFIG = {
  21         .bdist_max = 4,
  22
  23         .spat_min = 3, .spat_max = MAX_PATTERN_DIST,
  24         .spat_largest = true,
  25 };
  26
  27 #define PF_MATCH 15
  28
  29 pattern_spec PATTERN_SPEC_MATCH_DEFAULT = {
  30         [FEAT_CAPTURE] = ~0,
  31         [FEAT_AESCAPE] = ~0,
  32         [FEAT_SELFATARI] = ~0,
  33         [FEAT_ATARI] = ~0,
  34         [FEAT_BORDER] = ~0,
  35         [FEAT_CONTIGUITY] = 0,
  36         [FEAT_SPATIAL] = ~0,
  37 };
  38
  39 static const struct feature_info {
  40         char *name;
  41         int payloads;
  42 } features[FEAT_MAX] = {
  43         [FEAT_CAPTURE] = { .name = "capture", .payloads = 64 },
  44         [FEAT_AESCAPE] = { .name = "atariescape", .payloads = 16 },
  45         [FEAT_SELFATARI] = { .name = "selfatari", .payloads = 4 },
  46         [FEAT_ATARI] = { .name = "atari", .payloads = 4 },
  47         [FEAT_BORDER] = { .name = "border", .payloads = -1 },
  48         [FEAT_CONTIGUITY] = { .name = "cont", .payloads = 2 },
  49         [FEAT_SPATIAL] = { .name = "s", .payloads = -1 },
  50 };
  51
  52 char *
  53 feature2str(char *str, struct feature *f)
  54 {
  55         return str + sprintf(str + strlen(str), "%s:%d", features[f->id].name, f->payload);
  56 }
  57
  58 char *
  59 str2feature(char *str, struct feature *f)
  60 {
  61         while (isspace(*str)) str++;
  62
  63         int unsigned flen = strcspn(str, ":");
  64         for (unsigned int i = 0; i < sizeof(features)/sizeof(features[0]); i++)
  65                 if (strlen(features[i].name) == flen && !strncmp(features[i].name, str, flen)) {
  66                         f->id = i;
  67                         goto found;
  68                 }
  69         fprintf(stderr, "invalid featurespec: %s[%d]\n", str, flen);
  70         exit(EXIT_FAILURE);
  71
  72 found:
  73         str += flen + 1;
  74         f->payload = strtoull(str, &str, 10);
  75         return str;
  76 }
  77
  78 char *
  79 feature_name(enum feature_id f)
  80 {
  81         return features[f].name;
  82 }
  83
  84 int
  85 feature_payloads(struct pattern_setup *pat, enum feature_id f)
  86 {
  87         switch (f) {
  88                 case FEAT_CAPTURE:
  89                         int payloads = features[f].payloads;
  90                         if (pat->ps[FEAT_CAPTURE] & (1<<PF_CAPTURE_COUNTSTONES))
  91                                 payloads *= CAPTURE_COUNTSTONES_MAX + 1;
  92                         return payloads;
  93                 case FEAT_SPATIAL:
  94                         assert(features[f].payloads < 0);
  95                         return pat->pc.spat_dict->nspatials;
  96                 case FEAT_BORDER:
  97                         assert(features[f].payloads < 0);
  98                         return pat->pc.bdist_max + 1;
  99                 default:
 100                         assert(features[f].payloads > 0);
 101                         return features[f].payloads;
 102         }
 103 }
 104
 105
 106 void
 107 patterns_init(struct pattern_setup *pat, char *arg, bool will_append, bool load_prob)
 108 {
 109         char *pdict_file = NULL;
 110
 111         memset(pat, 0, sizeof(*pat));
 112
 113         pat->pc = DEFAULT_PATTERN_CONFIG;
 114         pat->pc.spat_dict = spatial_dict_init(will_append, !load_prob);
 115
 116         memcpy(&pat->ps, PATTERN_SPEC_MATCH_DEFAULT, sizeof(pattern_spec));
 117
 118         if (arg) {
 119                 char *optspec, *next = arg;
 120                 while (*next) {
 121                         optspec = next;
 122                         next += strcspn(next, ":");
 123                         if (*next) { *next++ = 0; } else { *next = 0; }
 124
 125                         char *optname = optspec;
 126                         char *optval = strchr(optspec, '=');
 127                         if (optval) *optval++ = 0;
 128
 129                         /* See pattern.h:pattern_config for description and
 130                          * pattern.c:DEFAULT_PATTERN_CONFIG for default values
 131                          * of the following options. */
 132                         if (!strcasecmp(optname, "bdist_max") && optval) {
 133                                 pat->pc.bdist_max = atoi(optval);
 134                         } else if (!strcasecmp(optname, "spat_min") && optval) {
 135                                 pat->pc.spat_min = atoi(optval);
 136                         } else if (!strcasecmp(optname, "spat_max") && optval) {
 137                                 pat->pc.spat_max = atoi(optval);
 138                         } else if (!strcasecmp(optname, "spat_largest")) {
 139                                 pat->pc.spat_largest = !optval || atoi(optval);
 140
 141                         } else if (!strcasecmp(optname, "pdict_file") && optval) {
 142                                 pdict_file = optval;
 143
 144                         } else {
 145                                 fprintf(stderr, "patterns: Invalid argument %s or missing value\n", optname);
 146                                 exit(EXIT_FAILURE);
 147                         }
 148                 }
 149         }
 150
 151         if (load_prob && pat->pc.spat_dict) {
 152                 pat->pd = pattern_pdict_init(pdict_file, &pat->pc);
 153         }
 154 }
 155
 156
 157 /* pattern_spec helpers */
 158 #define PS_ANY(F) (ps[FEAT_ ## F] & (1 << PF_MATCH))
 159 #define PS_PF(F, P) (ps[FEAT_ ## F] & (1 << PF_ ## F ## _ ## P))
 160
 161 static struct feature *
 162 pattern_match_capture(struct pattern_config *pc, pattern_spec ps,
 163                       struct pattern *p, struct feature *f,
 164                       struct board *b, struct move *m)
 165 {
 166         f->id = FEAT_CAPTURE; f->payload = 0;
 167 #ifdef BOARD_TRAITS
 168         if (!trait_at(b, m->coord, m->color).cap)
 169                 return f;
 170         /* Capturable! */
 171         if ((ps[FEAT_CAPTURE] & ~(1<<PF_CAPTURE_1STONE | 1<<PF_CAPTURE_TRAPPED | 1<<PF_CAPTURE_CONNECTION)) == 1<<PF_MATCH) {
 172                 if (PS_PF(CAPTURE, 1STONE))
 173                         f->payload |= (trait_at(b, m->coord, m->color).cap1 == trait_at(b, m->coord, m->color).cap) << PF_CAPTURE_1STONE;
 174                 if (PS_PF(CAPTURE, TRAPPED))
 175                         f->payload |= (!trait_at(b, m->coord, stone_other(m->color)).safe) << PF_CAPTURE_TRAPPED;
 176                 if (PS_PF(CAPTURE, CONNECTION))
 177                         f->payload |= (trait_at(b, m->coord, m->color).cap < neighbor_count_at(b, m->coord, stone_other(m->color))) << PF_CAPTURE_CONNECTION;
 178                 (f++, p->n++);
 179                 return f;
 180         }
 181         /* We need to know details, so we still have to go through
 182          * the neighbors. */
 183 #endif
 184
 185         /* We look at neighboring groups we could capture, and also if the
 186          * opponent could save them. */
 187         /* This is very similar in spirit to board_safe_to_play(), and almost
 188          * a color inverse of pattern_match_aescape(). */
 189
 190         /* Whether an escape move would be safe for the opponent. */
 191         int captures = 0;
 192         coord_t onelib = -1;
 193         int extra_libs = 0, connectable_groups = 0;
 194         bool onestone = false, multistone = false;
 195         int captured_stones = 0;
 196
 197         foreach_neighbor(b, m->coord, {
 198                 if (board_at(b, c) != stone_other(m->color)) {
 199                         if (board_at(b, c) == S_NONE)
 200                                 extra_libs++; // free point
 201                         else if (board_at(b, c) == m->color && board_group_info(b, group_at(b, c)).libs == 1)
 202                                 extra_libs += 2; // capturable enemy group
 203                         continue;
 204                 }
 205
 206                 group_t g = group_at(b, c); assert(g);
 207                 if (board_group_info(b, g).libs > 1) {
 208                         connectable_groups++;
 209                         if (board_group_info(b, g).libs > 2) {
 210                                 extra_libs += 2; // connected out
 211                         } else {
 212                                 /* This is a bit tricky; we connect our 2-lib
 213                                  * group to another 2-lib group, which counts
 214                                  * as one liberty, but only if the other lib
 215                                  * is not shared too. */
 216                                 if (onelib == -1) {
 217                                         onelib = board_group_other_lib(b, g, c);
 218                                         extra_libs++;
 219                                 } else {
 220                                         if (c == onelib)
 221                                                 extra_libs--; // take that back
 222                                         else
 223                                                 extra_libs++;
 224                                 }
 225                         }
 226                         continue;
 227                 }
 228
 229                 /* Capture! */
 230                 captures++;
 231
 232                 if (PS_PF(CAPTURE, LADDER))
 233                         f->payload |= is_ladder(b, m->coord, g, true) << PF_CAPTURE_LADDER;
 234                 /* TODO: is_ladder() is too conservative in some
 235                  * very obvious situations, look at complete.gtp. */
 236
 237                 if (PS_PF(CAPTURE, ATARIDEF))
 238                 foreach_in_group(b, g) {
 239                         foreach_neighbor(b, c, {
 240                                 assert(board_at(b, c) != S_NONE || c == m->coord);
 241                                 if (board_at(b, c) != m->color)
 242                                         continue;
 243                                 group_t g = group_at(b, c);
 244                                 if (!g || board_group_info(b, g).libs != 1)
 245                                         continue;
 246                                 /* A neighboring group of ours is in atari. */
 247                                 f->payload |= 1 << PF_CAPTURE_ATARIDEF;
 248                         });
 249                 } foreach_in_group_end;
 250
 251                 if (PS_PF(CAPTURE, KO)
 252                     && group_is_onestone(b, g)
 253                     && neighbor_count_at(b, m->coord, stone_other(m->color))
 254                        + neighbor_count_at(b, m->coord, S_OFFBOARD) == 4)
 255                         f->payload |= 1 << PF_CAPTURE_KO;
 256
 257                 if (PS_PF(CAPTURE, COUNTSTONES)
 258                     && captured_stones < CAPTURE_COUNTSTONES_MAX)
 259                         captured_stones += group_stone_count(b, g, CAPTURE_COUNTSTONES_MAX - captured_stones);
 260
 261                 if (group_is_onestone(b, g))
 262                         onestone = true;
 263                 else
 264                         multistone = true;
 265         });
 266
 267         if (captures > 0) {
 268                 if (PS_PF(CAPTURE, 1STONE))
 269                         f->payload |= (onestone && !multistone) << PF_CAPTURE_1STONE;
 270                 if (PS_PF(CAPTURE, TRAPPED))
 271                         f->payload |= (extra_libs < 2) << PF_CAPTURE_TRAPPED;
 272                 if (PS_PF(CAPTURE, CONNECTION))
 273                         f->payload |= (connectable_groups > 0) << PF_CAPTURE_CONNECTION;
 274                 if (PS_PF(CAPTURE, COUNTSTONES))
 275                         f->payload |= captured_stones << PF_CAPTURE_COUNTSTONES;
 276                 (f++, p->n++);
 277         }
 278         return f;
 279 }
 280
 281 static struct feature *
 282 pattern_match_aescape(struct pattern_config *pc, pattern_spec ps,
 283                       struct pattern *p, struct feature *f,
 284                       struct board *b, struct move *m)
 285 {
 286         f->id = FEAT_AESCAPE; f->payload = 0;
 287 #ifdef BOARD_TRAITS
 288         if (!trait_at(b, m->coord, stone_other(m->color)).cap)
 289                 return f;
 290         /* Opponent can capture something! */
 291         if ((ps[FEAT_AESCAPE] & ~(1<<PF_AESCAPE_1STONE | 1<<PF_AESCAPE_TRAPPED | 1<<PF_AESCAPE_CONNECTION)) == 1<<PF_MATCH) {
 292                 if (PS_PF(AESCAPE, 1STONE))
 293                         f->payload |= (trait_at(b, m->coord, stone_other(m->color)).cap1 == trait_at(b, m->coord, stone_other(m->color)).cap) << PF_AESCAPE_1STONE;
 294                 if (PS_PF(AESCAPE, TRAPPED))
 295                         f->payload |= (!trait_at(b, m->coord, m->color).safe) << PF_AESCAPE_TRAPPED;
 296                 if (PS_PF(AESCAPE, CONNECTION))
 297                         f->payload |= (trait_at(b, m->coord, stone_other(m->color)).cap < neighbor_count_at(b, m->coord, m->color)) << PF_AESCAPE_CONNECTION;
 298                 (f++, p->n++);
 299                 return f;
 300         }
 301         /* We need to know details, so we still have to go through
 302          * the neighbors. */
 303 #endif
 304
 305         /* Find if a neighboring group of ours is in atari, AND that we provide
 306          * a liberty to connect out. XXX: No connect-and-die check. */
 307         /* This is very similar in spirit to board_safe_to_play(). */
 308         group_t in_atari = -1;
 309         coord_t onelib = -1;
 310         int extra_libs = 0, connectable_groups = 0;
 311         bool onestone = false, multistone = false;
 312
 313         foreach_neighbor(b, m->coord, {
 314                 if (board_at(b, c) != m->color) {
 315                         if (board_at(b, c) == S_NONE)
 316                                 extra_libs++; // free point
 317                         else if (board_at(b, c) == stone_other(m->color) && board_group_info(b, group_at(b, c)).libs == 1) {
 318                                 extra_libs += 2; // capturable enemy group
 319                                 /* XXX: We just consider this move safe
 320                                  * unconditionally. */
 321                         }
 322                         continue;
 323                 }
 324                 group_t g = group_at(b, c); assert(g);
 325                 if (board_group_info(b, g).libs > 1) {
 326                         connectable_groups++;
 327                         if (board_group_info(b, g).libs > 2) {
 328                                 extra_libs += 2; // connected out
 329                         } else {
 330                                 /* This is a bit tricky; we connect our 2-lib
 331                                  * group to another 2-lib group, which counts
 332                                  * as one liberty, but only if the other lib
 333                                  * is not shared too. */
 334                                 if (onelib == -1) {
 335                                         onelib = board_group_other_lib(b, g, c);
 336                                         extra_libs++;
 337                                 } else {
 338                                         if (c == onelib)
 339                                                 extra_libs--; // take that back
 340                                         else
 341                                                 extra_libs++;
 342                                 }
 343                         }
 344                         continue;
 345                 }
 346
 347                 /* In atari! */
 348                 in_atari = g;
 349
 350                 if (PS_PF(AESCAPE, LADDER))
 351                         f->payload |= is_ladder(b, m->coord, g, true) << PF_AESCAPE_LADDER;
 352                 /* TODO: is_ladder() is too conservative in some
 353                  * very obvious situations, look at complete.gtp. */
 354
 355                 if (group_is_onestone(b, g))
 356                         onestone = true;
 357                 else
 358                         multistone = true;
 359         });
 360
 361         if (in_atari >= 0) {
 362                 if (PS_PF(AESCAPE, 1STONE))
 363                         f->payload |= (onestone && !multistone) << PF_AESCAPE_1STONE;
 364                 if (PS_PF(AESCAPE, TRAPPED))
 365                         f->payload |= (extra_libs < 2) << PF_AESCAPE_TRAPPED;
 366                 if (PS_PF(AESCAPE, CONNECTION))
 367                         f->payload |= (connectable_groups > 0) << PF_AESCAPE_CONNECTION;
 368                 (f++, p->n++);
 369         }
 370         return f;
 371 }
 372
 373 static struct feature *
 374 pattern_match_atari(struct pattern_config *pc, pattern_spec ps,
 375                     struct pattern *p, struct feature *f,
 376                     struct board *b, struct move *m)
 377 {
 378         foreach_neighbor(b, m->coord, {
 379                 if (board_at(b, c) != stone_other(m->color))
 380                         continue;
 381                 group_t g = group_at(b, c);
 382                 if (!g || board_group_info(b, g).libs != 2)
 383                         continue;
 384
 385                 /* Can atari! */
 386                 f->id = FEAT_ATARI; f->payload = 0;
 387
 388                 if (PS_PF(ATARI, LADDER)) {
 389                         /* Opponent will escape by the other lib. */
 390                         coord_t lib = board_group_other_lib(b, g, m->coord);
 391                         /* TODO: is_ladder() is too conservative in some
 392                          * very obvious situations, look at complete.gtp. */
 393                         f->payload |= wouldbe_ladder(b, g, lib, m->coord, stone_other(m->color)) << PF_ATARI_LADDER;
 394                 }
 395
 396                 if (PS_PF(ATARI, KO) && !is_pass(b->ko.coord))
 397                         f->payload |= 1 << PF_ATARI_KO;
 398
 399                 (f++, p->n++);
 400         });
 401         return f;
 402 }
 403
 404 #ifndef BOARD_SPATHASH
 405 #undef BOARD_SPATHASH_MAXD
 406 #define BOARD_SPATHASH_MAXD 1
 407 #endif
 408
 409 /* Match spatial features that are too distant to be pre-matched
 410  * incrementally. */
 411 struct feature *
 412 pattern_match_spatial_outer(struct pattern_config *pc, pattern_spec ps,
 413                             struct pattern *p, struct feature *f,
 414                             struct board *b, struct move *m, hash_t h)
 415 {
 416         /* We record all spatial patterns black-to-play; simply
 417          * reverse all colors if we are white-to-play. */
 418         static enum stone bt_black[4] = { S_NONE, S_BLACK, S_WHITE, S_OFFBOARD };
 419         static enum stone bt_white[4] = { S_NONE, S_WHITE, S_BLACK, S_OFFBOARD };
 420         enum stone (*bt)[4] = m->color == S_WHITE ? &bt_white : &bt_black;
 421
 422         for (unsigned int d = BOARD_SPATHASH_MAXD + 1; d <= pc->spat_max; d++) {
 423                 /* Recompute missing outer circles:
 424                  * Go through all points in given distance. */
 425                 for (unsigned int j = ptind[d]; j < ptind[d + 1]; j++) {
 426                         ptcoords_at(x, y, m->coord, b, j);
 427                         h ^= pthashes[0][j][(*bt)[board_atxy(b, x, y)]];
 428                 }
 429                 if (d < pc->spat_min)
 430                         continue;
 431                 /* Record spatial feature, one per distance. */
 432                 unsigned int sid = spatial_dict_get(pc->spat_dict, d, h & spatial_hash_mask);
 433                 if (sid > 0) {
 434                         f->id = FEAT_SPATIAL;
 435                         f->payload = sid;
 436                         if (!pc->spat_largest)
 437                                 (f++, p->n++);
 438                 } /* else not found, ignore */
 439         }
 440         return f;
 441 }
 442
 443 struct feature *
 444 pattern_match_spatial(struct pattern_config *pc, pattern_spec ps,
 445                       struct pattern *p, struct feature *f,
 446                       struct board *b, struct move *m)
 447 {
 448         /* XXX: This is partially duplicated from spatial_from_board(), but
 449          * we build a hash instead of spatial record. */
 450
 451         assert(pc->spat_min > 0);
 452         f->id = -1;
 453
 454         hash_t h = pthashes[0][0][S_NONE];
 455 #ifdef BOARD_SPATHASH
 456         bool w_to_play = m->color == S_WHITE;
 457         for (int d = 2; d <= BOARD_SPATHASH_MAXD; d++) {
 458                 /* Reuse all incrementally matched data. */
 459                 h ^= b->spathash[m->coord][d - 1][w_to_play];
 460                 if (d < pc->spat_min)
 461                         continue;
 462                 /* Record spatial feature, one per distance. */
 463                 unsigned int sid = spatial_dict_get(pc->spat_dict, d, h & spatial_hash_mask);
 464                 if (sid > 0) {
 465                         f->id = FEAT_SPATIAL;
 466                         f->payload = sid;
 467                         if (!pc->spat_largest)
 468                                 (f++, p->n++);
 469                 } /* else not found, ignore */
 470         }
 471 #else
 472         assert(BOARD_SPATHASH_MAXD < 2);
 473 #endif
 474         if (unlikely(pc->spat_max > BOARD_SPATHASH_MAXD))
 475                 f = pattern_match_spatial_outer(pc, ps, p, f, b, m, h);
 476         if (pc->spat_largest && f->id == FEAT_SPATIAL)
 477                 (f++, p->n++);
 478         return f;
 479 }
 480
 481
 482 void
 483 pattern_match(struct pattern_config *pc, pattern_spec ps,
 484               struct pattern *p, struct board *b, struct move *m)
 485 {
 486         p->n = 0;
 487         struct feature *f = &p->f[0];
 488
 489         /* TODO: We should match pretty much all of these features
 490          * incrementally. */
 491
 492         if (PS_ANY(CAPTURE)) {
 493                 f = pattern_match_capture(pc, ps, p, f, b, m);
 494         }
 495
 496         if (PS_ANY(AESCAPE)) {
 497                 f = pattern_match_aescape(pc, ps, p, f, b, m);
 498         }
 499
 500         if (PS_ANY(SELFATARI)) {
 501                 bool simple = false;
 502                 if (PS_PF(SELFATARI, STUPID)) {
 503 #ifdef BOARD_TRAITS
 504                         if (!b->precise_selfatari)
 505                                 simple = !trait_at(b, m->coord, m->color).safe;
 506                         else
 507 #endif
 508                         simple = !board_safe_to_play(b, m->coord, m->color);
 509                 }
 510                 bool thorough = false;
 511                 if (PS_PF(SELFATARI, SMART)) {
 512 #ifdef BOARD_TRAITS
 513                         if (b->precise_selfatari)
 514                                 thorough = !trait_at(b, m->coord, m->color).safe;
 515                         else
 516 #endif
 517                         thorough = is_bad_selfatari(b, m->color, m->coord);
 518                 }
 519                 if (simple || thorough) {
 520                         f->id = FEAT_SELFATARI;
 521                         f->payload = simple << PF_SELFATARI_STUPID;
 522                         f->payload |= thorough << PF_SELFATARI_SMART;
 523                         (f++, p->n++);
 524                 }
 525         }
 526
 527         if (PS_ANY(ATARI)) {
 528                 f = pattern_match_atari(pc, ps, p, f, b, m);
 529         }
 530
 531         if (PS_ANY(BORDER)) {
 532                 unsigned int bdist = coord_edge_distance(m->coord, b);
 533                 if (bdist <= pc->bdist_max) {
 534                         f->id = FEAT_BORDER;
 535                         f->payload = bdist;
 536                         (f++, p->n++);
 537                 }
 538         }
 539
 540         if (PS_ANY(CONTIGUITY) && !is_pass(b->last_move.coord)
 541             && coord_is_8adjecent(m->coord, b->last_move.coord, b)) {
 542                 f->id = FEAT_CONTIGUITY;
 543                 f->payload = 1;
 544                 (f++, p->n++);
 545         }
 546
 547         if (PS_ANY(SPATIAL) && pc->spat_max > 0 && pc->spat_dict) {
 548                 f = pattern_match_spatial(pc, ps, p, f, b, m);
 549         }
 550 }
 551
 552 char *
 553 pattern2str(char *str, struct pattern *p)
 554 {
 555         str = stpcpy(str, "(");
 556         for (int i = 0; i < p->n; i++) {
 557                 if (i > 0) str = stpcpy(str, " ");
 558                 str = feature2str(str, &p->f[i]);
 559         }
 560         str = stpcpy(str, ")");
 561         return str;
 562 }
 563
 564 char *
 565 str2pattern(char *str, struct pattern *p)
 566 {
 567         p->n = 0;
 568         while (isspace(*str)) str++;
 569         if (*str++ != '(') {
 570                 fprintf(stderr, "invalid patternspec: %s\n", str);
 571                 exit(EXIT_FAILURE);
 572         }
 573
 574         while (*str != ')') {
 575                 str = str2feature(str, &p->f[p->n++]);
 576         }
 577
 578         str++;
 579         return str;
 580 }