| 1 | /* |
| 2 | * NFA utilities. |
| 3 | * This file is #included by regcomp.c. |
| 4 | * |
| 5 | * Copyright (c) 1998, 1999 Henry Spencer. All rights reserved. |
| 6 | * |
| 7 | * Development of this software was funded, in part, by Cray Research Inc., |
| 8 | * UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics |
| 9 | * Corporation, none of whom are responsible for the results. The author |
| 10 | * thanks all of them. |
| 11 | * |
| 12 | * Redistribution and use in source and binary forms -- with or without |
| 13 | * modification -- are permitted for any purpose, provided that |
| 14 | * redistributions in source form retain this entire copyright notice and |
| 15 | * indicate the origin and nature of any modifications. |
| 16 | * |
| 17 | * I'd appreciate being given credit for this package in the documentation |
| 18 | * of software which uses it, but that is not a requirement. |
| 19 | * |
| 20 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, |
| 21 | * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY |
| 22 | * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL |
| 23 | * HENRY SPENCER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| 24 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 25 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; |
| 26 | * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| 27 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| 28 | * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| 29 | * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 30 | * |
| 31 | * |
| 32 | * |
| 33 | * One or two things that technically ought to be in here |
| 34 | * are actually in color.c, thanks to some incestuous relationships in |
| 35 | * the color chains. |
| 36 | */ |
| 37 | |
| 38 | #define NISERR() VISERR(nfa->v) |
| 39 | #define NERR(e) VERR(nfa->v, (e)) |
| 40 | |
| 41 | |
| 42 | /* |
| 43 | - newnfa - set up an NFA |
| 44 | ^ static struct nfa *newnfa(struct vars *, struct colormap *, struct nfa *); |
| 45 | */ |
| 46 | static struct nfa * /* the NFA, or NULL */ |
| 47 | newnfa(v, cm, parent) |
| 48 | struct vars *v; |
| 49 | struct colormap *cm; |
| 50 | struct nfa *parent; /* NULL if primary NFA */ |
| 51 | { |
| 52 | struct nfa *nfa; |
| 53 | |
| 54 | nfa = (struct nfa *)MALLOC(sizeof(struct nfa)); |
| 55 | if (nfa == NULL) |
| 56 | return NULL; |
| 57 | |
| 58 | nfa->states = NULL; |
| 59 | nfa->slast = NULL; |
| 60 | nfa->free = NULL; |
| 61 | nfa->nstates = 0; |
| 62 | nfa->cm = cm; |
| 63 | nfa->v = v; |
| 64 | nfa->bos[0] = nfa->bos[1] = COLORLESS; |
| 65 | nfa->eos[0] = nfa->eos[1] = COLORLESS; |
| 66 | nfa->post = newfstate(nfa, '@'); /* number 0 */ |
| 67 | nfa->pre = newfstate(nfa, '>'); /* number 1 */ |
| 68 | nfa->parent = parent; |
| 69 | |
| 70 | nfa->init = newstate(nfa); /* may become invalid later */ |
| 71 | nfa->final = newstate(nfa); |
| 72 | if (ISERR()) { |
| 73 | freenfa(nfa); |
| 74 | return NULL; |
| 75 | } |
| 76 | rainbow(nfa, nfa->cm, PLAIN, COLORLESS, nfa->pre, nfa->init); |
| 77 | newarc(nfa, '^', 1, nfa->pre, nfa->init); |
| 78 | newarc(nfa, '^', 0, nfa->pre, nfa->init); |
| 79 | rainbow(nfa, nfa->cm, PLAIN, COLORLESS, nfa->final, nfa->post); |
| 80 | newarc(nfa, '$', 1, nfa->final, nfa->post); |
| 81 | newarc(nfa, '$', 0, nfa->final, nfa->post); |
| 82 | |
| 83 | if (ISERR()) { |
| 84 | freenfa(nfa); |
| 85 | return NULL; |
| 86 | } |
| 87 | return nfa; |
| 88 | } |
| 89 | |
| 90 | /* |
| 91 | - freenfa - free an entire NFA |
| 92 | ^ static VOID freenfa(struct nfa *); |
| 93 | */ |
| 94 | static VOID |
| 95 | freenfa(nfa) |
| 96 | struct nfa *nfa; |
| 97 | { |
| 98 | struct state *s; |
| 99 | |
| 100 | while ((s = nfa->states) != NULL) { |
| 101 | s->nins = s->nouts = 0; /* don't worry about arcs */ |
| 102 | freestate(nfa, s); |
| 103 | } |
| 104 | while ((s = nfa->free) != NULL) { |
| 105 | nfa->free = s->next; |
| 106 | destroystate(nfa, s); |
| 107 | } |
| 108 | |
| 109 | nfa->slast = NULL; |
| 110 | nfa->nstates = -1; |
| 111 | nfa->pre = NULL; |
| 112 | nfa->post = NULL; |
| 113 | FREE(nfa); |
| 114 | } |
| 115 | |
| 116 | /* |
| 117 | - newstate - allocate an NFA state, with zero flag value |
| 118 | ^ static struct state *newstate(struct nfa *); |
| 119 | */ |
| 120 | static struct state * /* NULL on error */ |
| 121 | newstate(nfa) |
| 122 | struct nfa *nfa; |
| 123 | { |
| 124 | struct state *s; |
| 125 | |
| 126 | if (nfa->free != NULL) { |
| 127 | s = nfa->free; |
| 128 | nfa->free = s->next; |
| 129 | } else { |
| 130 | s = (struct state *)MALLOC(sizeof(struct state)); |
| 131 | if (s == NULL) { |
| 132 | NERR(REG_ESPACE); |
| 133 | return NULL; |
| 134 | } |
| 135 | s->oas.next = NULL; |
| 136 | s->free = NULL; |
| 137 | s->noas = 0; |
| 138 | } |
| 139 | |
| 140 | assert(nfa->nstates >= 0); |
| 141 | s->no = nfa->nstates++; |
| 142 | s->flag = 0; |
| 143 | if (nfa->states == NULL) |
| 144 | nfa->states = s; |
| 145 | s->nins = 0; |
| 146 | s->ins = NULL; |
| 147 | s->nouts = 0; |
| 148 | s->outs = NULL; |
| 149 | s->tmp = NULL; |
| 150 | s->next = NULL; |
| 151 | if (nfa->slast != NULL) { |
| 152 | assert(nfa->slast->next == NULL); |
| 153 | nfa->slast->next = s; |
| 154 | } |
| 155 | s->prev = nfa->slast; |
| 156 | nfa->slast = s; |
| 157 | return s; |
| 158 | } |
| 159 | |
| 160 | /* |
| 161 | - newfstate - allocate an NFA state with a specified flag value |
| 162 | ^ static struct state *newfstate(struct nfa *, int flag); |
| 163 | */ |
| 164 | static struct state * /* NULL on error */ |
| 165 | newfstate(nfa, flag) |
| 166 | struct nfa *nfa; |
| 167 | int flag; |
| 168 | { |
| 169 | struct state *s; |
| 170 | |
| 171 | s = newstate(nfa); |
| 172 | if (s != NULL) |
| 173 | s->flag = (char)flag; |
| 174 | return s; |
| 175 | } |
| 176 | |
| 177 | /* |
| 178 | - dropstate - delete a state's inarcs and outarcs and free it |
| 179 | ^ static VOID dropstate(struct nfa *, struct state *); |
| 180 | */ |
| 181 | static VOID |
| 182 | dropstate(nfa, s) |
| 183 | struct nfa *nfa; |
| 184 | struct state *s; |
| 185 | { |
| 186 | struct arc *a; |
| 187 | |
| 188 | while ((a = s->ins) != NULL) |
| 189 | freearc(nfa, a); |
| 190 | while ((a = s->outs) != NULL) |
| 191 | freearc(nfa, a); |
| 192 | freestate(nfa, s); |
| 193 | } |
| 194 | |
| 195 | /* |
| 196 | - freestate - free a state, which has no in-arcs or out-arcs |
| 197 | ^ static VOID freestate(struct nfa *, struct state *); |
| 198 | */ |
| 199 | static VOID |
| 200 | freestate(nfa, s) |
| 201 | struct nfa *nfa; |
| 202 | struct state *s; |
| 203 | { |
| 204 | assert(s != NULL); |
| 205 | assert(s->nins == 0 && s->nouts == 0); |
| 206 | |
| 207 | s->no = FREESTATE; |
| 208 | s->flag = 0; |
| 209 | if (s->next != NULL) |
| 210 | s->next->prev = s->prev; |
| 211 | else { |
| 212 | assert(s == nfa->slast); |
| 213 | nfa->slast = s->prev; |
| 214 | } |
| 215 | if (s->prev != NULL) |
| 216 | s->prev->next = s->next; |
| 217 | else { |
| 218 | assert(s == nfa->states); |
| 219 | nfa->states = s->next; |
| 220 | } |
| 221 | s->prev = NULL; |
| 222 | s->next = nfa->free; /* don't delete it, put it on the free list */ |
| 223 | nfa->free = s; |
| 224 | } |
| 225 | |
| 226 | /* |
| 227 | - destroystate - really get rid of an already-freed state |
| 228 | ^ static VOID destroystate(struct nfa *, struct state *); |
| 229 | */ |
| 230 | static VOID |
| 231 | destroystate(nfa, s) |
| 232 | struct nfa *nfa; |
| 233 | struct state *s; |
| 234 | { |
| 235 | struct arcbatch *ab; |
| 236 | struct arcbatch *abnext; |
| 237 | |
| 238 | assert(s->no == FREESTATE); |
| 239 | for (ab = s->oas.next; ab != NULL; ab = abnext) { |
| 240 | abnext = ab->next; |
| 241 | FREE(ab); |
| 242 | } |
| 243 | s->ins = NULL; |
| 244 | s->outs = NULL; |
| 245 | s->next = NULL; |
| 246 | FREE(s); |
| 247 | } |
| 248 | |
| 249 | /* |
| 250 | - newarc - set up a new arc within an NFA |
| 251 | ^ static VOID newarc(struct nfa *, int, pcolor, struct state *, |
| 252 | ^ struct state *); |
| 253 | */ |
| 254 | static VOID |
| 255 | newarc(nfa, t, co, from, to) |
| 256 | struct nfa *nfa; |
| 257 | int t; |
| 258 | pcolor co; |
| 259 | struct state *from; |
| 260 | struct state *to; |
| 261 | { |
| 262 | struct arc *a; |
| 263 | |
| 264 | assert(from != NULL && to != NULL); |
| 265 | |
| 266 | /* check for duplicates */ |
| 267 | for (a = from->outs; a != NULL; a = a->outchain) |
| 268 | if (a->to == to && a->co == co && a->type == t) |
| 269 | return; |
| 270 | |
| 271 | a = allocarc(nfa, from); |
| 272 | if (NISERR()) |
| 273 | return; |
| 274 | assert(a != NULL); |
| 275 | |
| 276 | a->type = t; |
| 277 | a->co = (color)co; |
| 278 | a->to = to; |
| 279 | a->from = from; |
| 280 | |
| 281 | /* |
| 282 | * Put the new arc on the beginning, not the end, of the chains. |
| 283 | * Not only is this easier, it has the very useful side effect that |
| 284 | * deleting the most-recently-added arc is the cheapest case rather |
| 285 | * than the most expensive one. |
| 286 | */ |
| 287 | a->inchain = to->ins; |
| 288 | to->ins = a; |
| 289 | a->outchain = from->outs; |
| 290 | from->outs = a; |
| 291 | |
| 292 | from->nouts++; |
| 293 | to->nins++; |
| 294 | |
| 295 | if (COLORED(a) && nfa->parent == NULL) |
| 296 | colorchain(nfa->cm, a); |
| 297 | |
| 298 | return; |
| 299 | } |
| 300 | |
| 301 | /* |
| 302 | - allocarc - allocate a new out-arc within a state |
| 303 | ^ static struct arc *allocarc(struct nfa *, struct state *); |
| 304 | */ |
| 305 | static struct arc * /* NULL for failure */ |
| 306 | allocarc(nfa, s) |
| 307 | struct nfa *nfa; |
| 308 | struct state *s; |
| 309 | { |
| 310 | struct arc *a; |
| 311 | struct arcbatch *new; |
| 312 | int i; |
| 313 | |
| 314 | /* shortcut */ |
| 315 | if (s->free == NULL && s->noas < ABSIZE) { |
| 316 | a = &s->oas.a[s->noas]; |
| 317 | s->noas++; |
| 318 | return a; |
| 319 | } |
| 320 | |
| 321 | /* if none at hand, get more */ |
| 322 | if (s->free == NULL) { |
| 323 | new = (struct arcbatch *)MALLOC(sizeof(struct arcbatch)); |
| 324 | if (new == NULL) { |
| 325 | NERR(REG_ESPACE); |
| 326 | return NULL; |
| 327 | } |
| 328 | new->next = s->oas.next; |
| 329 | s->oas.next = new; |
| 330 | |
| 331 | for (i = 0; i < ABSIZE; i++) { |
| 332 | new->a[i].type = 0; |
| 333 | new->a[i].freechain = &new->a[i+1]; |
| 334 | } |
| 335 | new->a[ABSIZE-1].freechain = NULL; |
| 336 | s->free = &new->a[0]; |
| 337 | } |
| 338 | assert(s->free != NULL); |
| 339 | |
| 340 | a = s->free; |
| 341 | s->free = a->freechain; |
| 342 | return a; |
| 343 | } |
| 344 | |
| 345 | /* |
| 346 | - freearc - free an arc |
| 347 | ^ static VOID freearc(struct nfa *, struct arc *); |
| 348 | */ |
| 349 | static VOID |
| 350 | freearc(nfa, victim) |
| 351 | struct nfa *nfa; |
| 352 | struct arc *victim; |
| 353 | { |
| 354 | struct state *from = victim->from; |
| 355 | struct state *to = victim->to; |
| 356 | struct arc *a; |
| 357 | |
| 358 | assert(victim->type != 0); |
| 359 | |
| 360 | /* take it off color chain if necessary */ |
| 361 | if (COLORED(victim) && nfa->parent == NULL) |
| 362 | uncolorchain(nfa->cm, victim); |
| 363 | |
| 364 | /* take it off source's out-chain */ |
| 365 | assert(from != NULL); |
| 366 | assert(from->outs != NULL); |
| 367 | a = from->outs; |
| 368 | if (a == victim) /* simple case: first in chain */ |
| 369 | from->outs = victim->outchain; |
| 370 | else { |
| 371 | for (; a != NULL && a->outchain != victim; a = a->outchain) |
| 372 | continue; |
| 373 | assert(a != NULL); |
| 374 | a->outchain = victim->outchain; |
| 375 | } |
| 376 | from->nouts--; |
| 377 | |
| 378 | /* take it off target's in-chain */ |
| 379 | assert(to != NULL); |
| 380 | assert(to->ins != NULL); |
| 381 | a = to->ins; |
| 382 | if (a == victim) /* simple case: first in chain */ |
| 383 | to->ins = victim->inchain; |
| 384 | else { |
| 385 | for (; a != NULL && a->inchain != victim; a = a->inchain) |
| 386 | continue; |
| 387 | assert(a != NULL); |
| 388 | a->inchain = victim->inchain; |
| 389 | } |
| 390 | to->nins--; |
| 391 | |
| 392 | /* clean up and place on free list */ |
| 393 | victim->type = 0; |
| 394 | victim->from = NULL; /* precautions... */ |
| 395 | victim->to = NULL; |
| 396 | victim->inchain = NULL; |
| 397 | victim->outchain = NULL; |
| 398 | victim->freechain = from->free; |
| 399 | from->free = victim; |
| 400 | } |
| 401 | |
| 402 | /* |
| 403 | - findarc - find arc, if any, from given source with given type and color |
| 404 | * If there is more than one such arc, the result is random. |
| 405 | ^ static struct arc *findarc(struct state *, int, pcolor); |
| 406 | */ |
| 407 | static struct arc * |
| 408 | findarc(s, type, co) |
| 409 | struct state *s; |
| 410 | int type; |
| 411 | pcolor co; |
| 412 | { |
| 413 | struct arc *a; |
| 414 | |
| 415 | for (a = s->outs; a != NULL; a = a->outchain) |
| 416 | if (a->type == type && a->co == co) |
| 417 | return a; |
| 418 | return NULL; |
| 419 | } |
| 420 | |
| 421 | /* |
| 422 | - cparc - allocate a new arc within an NFA, copying details from old one |
| 423 | ^ static VOID cparc(struct nfa *, struct arc *, struct state *, |
| 424 | ^ struct state *); |
| 425 | */ |
| 426 | static VOID |
| 427 | cparc(nfa, oa, from, to) |
| 428 | struct nfa *nfa; |
| 429 | struct arc *oa; |
| 430 | struct state *from; |
| 431 | struct state *to; |
| 432 | { |
| 433 | newarc(nfa, oa->type, oa->co, from, to); |
| 434 | } |
| 435 | |
| 436 | /* |
| 437 | - moveins - move all in arcs of a state to another state |
| 438 | * You might think this could be done better by just updating the |
| 439 | * existing arcs, and you would be right if it weren't for the desire |
| 440 | * for duplicate suppression, which makes it easier to just make new |
| 441 | * ones to exploit the suppression built into newarc. |
| 442 | ^ static VOID moveins(struct nfa *, struct state *, struct state *); |
| 443 | */ |
| 444 | static VOID |
| 445 | moveins(nfa, old, new) |
| 446 | struct nfa *nfa; |
| 447 | struct state *old; |
| 448 | struct state *new; |
| 449 | { |
| 450 | struct arc *a; |
| 451 | |
| 452 | assert(old != new); |
| 453 | |
| 454 | while ((a = old->ins) != NULL) { |
| 455 | cparc(nfa, a, a->from, new); |
| 456 | freearc(nfa, a); |
| 457 | } |
| 458 | assert(old->nins == 0); |
| 459 | assert(old->ins == NULL); |
| 460 | } |
| 461 | |
| 462 | /* |
| 463 | - copyins - copy all in arcs of a state to another state |
| 464 | ^ static VOID copyins(struct nfa *, struct state *, struct state *); |
| 465 | */ |
| 466 | static VOID |
| 467 | copyins(nfa, old, new) |
| 468 | struct nfa *nfa; |
| 469 | struct state *old; |
| 470 | struct state *new; |
| 471 | { |
| 472 | struct arc *a; |
| 473 | |
| 474 | assert(old != new); |
| 475 | |
| 476 | for (a = old->ins; a != NULL; a = a->inchain) |
| 477 | cparc(nfa, a, a->from, new); |
| 478 | } |
| 479 | |
| 480 | /* |
| 481 | - moveouts - move all out arcs of a state to another state |
| 482 | ^ static VOID moveouts(struct nfa *, struct state *, struct state *); |
| 483 | */ |
| 484 | static VOID |
| 485 | moveouts(nfa, old, new) |
| 486 | struct nfa *nfa; |
| 487 | struct state *old; |
| 488 | struct state *new; |
| 489 | { |
| 490 | struct arc *a; |
| 491 | |
| 492 | assert(old != new); |
| 493 | |
| 494 | while ((a = old->outs) != NULL) { |
| 495 | cparc(nfa, a, new, a->to); |
| 496 | freearc(nfa, a); |
| 497 | } |
| 498 | } |
| 499 | |
| 500 | /* |
| 501 | - copyouts - copy all out arcs of a state to another state |
| 502 | ^ static VOID copyouts(struct nfa *, struct state *, struct state *); |
| 503 | */ |
| 504 | static VOID |
| 505 | copyouts(nfa, old, new) |
| 506 | struct nfa *nfa; |
| 507 | struct state *old; |
| 508 | struct state *new; |
| 509 | { |
| 510 | struct arc *a; |
| 511 | |
| 512 | assert(old != new); |
| 513 | |
| 514 | for (a = old->outs; a != NULL; a = a->outchain) |
| 515 | cparc(nfa, a, new, a->to); |
| 516 | } |
| 517 | |
| 518 | /* |
| 519 | - cloneouts - copy out arcs of a state to another state pair, modifying type |
| 520 | ^ static VOID cloneouts(struct nfa *, struct state *, struct state *, |
| 521 | ^ struct state *, int); |
| 522 | */ |
| 523 | static VOID |
| 524 | cloneouts(nfa, old, from, to, type) |
| 525 | struct nfa *nfa; |
| 526 | struct state *old; |
| 527 | struct state *from; |
| 528 | struct state *to; |
| 529 | int type; |
| 530 | { |
| 531 | struct arc *a; |
| 532 | |
| 533 | assert(old != from); |
| 534 | |
| 535 | for (a = old->outs; a != NULL; a = a->outchain) |
| 536 | newarc(nfa, type, a->co, from, to); |
| 537 | } |
| 538 | |
| 539 | /* |
| 540 | - delsub - delete a sub-NFA, updating subre pointers if necessary |
| 541 | * This uses a recursive traversal of the sub-NFA, marking already-seen |
| 542 | * states using their tmp pointer. |
| 543 | ^ static VOID delsub(struct nfa *, struct state *, struct state *); |
| 544 | */ |
| 545 | static VOID |
| 546 | delsub(nfa, lp, rp) |
| 547 | struct nfa *nfa; |
| 548 | struct state *lp; /* the sub-NFA goes from here... */ |
| 549 | struct state *rp; /* ...to here, *not* inclusive */ |
| 550 | { |
| 551 | assert(lp != rp); |
| 552 | |
| 553 | rp->tmp = rp; /* mark end */ |
| 554 | |
| 555 | deltraverse(nfa, lp, lp); |
| 556 | assert(lp->nouts == 0 && rp->nins == 0); /* did the job */ |
| 557 | assert(lp->no != FREESTATE && rp->no != FREESTATE); /* no more */ |
| 558 | |
| 559 | rp->tmp = NULL; /* unmark end */ |
| 560 | lp->tmp = NULL; /* and begin, marked by deltraverse */ |
| 561 | } |
| 562 | |
| 563 | /* |
| 564 | - deltraverse - the recursive heart of delsub |
| 565 | * This routine's basic job is to destroy all out-arcs of the state. |
| 566 | ^ static VOID deltraverse(struct nfa *, struct state *, struct state *); |
| 567 | */ |
| 568 | static VOID |
| 569 | deltraverse(nfa, leftend, s) |
| 570 | struct nfa *nfa; |
| 571 | struct state *leftend; |
| 572 | struct state *s; |
| 573 | { |
| 574 | struct arc *a; |
| 575 | struct state *to; |
| 576 | |
| 577 | if (s->nouts == 0) |
| 578 | return; /* nothing to do */ |
| 579 | if (s->tmp != NULL) |
| 580 | return; /* already in progress */ |
| 581 | |
| 582 | s->tmp = s; /* mark as in progress */ |
| 583 | |
| 584 | while ((a = s->outs) != NULL) { |
| 585 | to = a->to; |
| 586 | deltraverse(nfa, leftend, to); |
| 587 | assert(to->nouts == 0 || to->tmp != NULL); |
| 588 | freearc(nfa, a); |
| 589 | if (to->nins == 0 && to->tmp == NULL) { |
| 590 | assert(to->nouts == 0); |
| 591 | freestate(nfa, to); |
| 592 | } |
| 593 | } |
| 594 | |
| 595 | assert(s->no != FREESTATE); /* we're still here */ |
| 596 | assert(s == leftend || s->nins != 0); /* and still reachable */ |
| 597 | assert(s->nouts == 0); /* but have no outarcs */ |
| 598 | |
| 599 | s->tmp = NULL; /* we're done here */ |
| 600 | } |
| 601 | |
| 602 | /* |
| 603 | - dupnfa - duplicate sub-NFA |
| 604 | * Another recursive traversal, this time using tmp to point to duplicates |
| 605 | * as well as mark already-seen states. (You knew there was a reason why |
| 606 | * it's a state pointer, didn't you? :-)) |
| 607 | ^ static VOID dupnfa(struct nfa *, struct state *, struct state *, |
| 608 | ^ struct state *, struct state *); |
| 609 | */ |
| 610 | static VOID |
| 611 | dupnfa(nfa, start, stop, from, to) |
| 612 | struct nfa *nfa; |
| 613 | struct state *start; /* duplicate of subNFA starting here */ |
| 614 | struct state *stop; /* and stopping here */ |
| 615 | struct state *from; /* stringing duplicate from here */ |
| 616 | struct state *to; /* to here */ |
| 617 | { |
| 618 | if (start == stop) { |
| 619 | newarc(nfa, EMPTY, 0, from, to); |
| 620 | return; |
| 621 | } |
| 622 | |
| 623 | stop->tmp = to; |
| 624 | duptraverse(nfa, start, from); |
| 625 | /* done, except for clearing out the tmp pointers */ |
| 626 | |
| 627 | stop->tmp = NULL; |
| 628 | cleartraverse(nfa, start); |
| 629 | } |
| 630 | |
| 631 | /* |
| 632 | - duptraverse - recursive heart of dupnfa |
| 633 | ^ static VOID duptraverse(struct nfa *, struct state *, struct state *); |
| 634 | */ |
| 635 | static VOID |
| 636 | duptraverse(nfa, s, stmp) |
| 637 | struct nfa *nfa; |
| 638 | struct state *s; |
| 639 | struct state *stmp; /* s's duplicate, or NULL */ |
| 640 | { |
| 641 | struct arc *a; |
| 642 | |
| 643 | if (s->tmp != NULL) |
| 644 | return; /* already done */ |
| 645 | |
| 646 | s->tmp = (stmp == NULL) ? newstate(nfa) : stmp; |
| 647 | if (s->tmp == NULL) { |
| 648 | assert(NISERR()); |
| 649 | return; |
| 650 | } |
| 651 | |
| 652 | for (a = s->outs; a != NULL && !NISERR(); a = a->outchain) { |
| 653 | duptraverse(nfa, a->to, (struct state *)NULL); |
| 654 | assert(a->to->tmp != NULL); |
| 655 | cparc(nfa, a, s->tmp, a->to->tmp); |
| 656 | } |
| 657 | } |
| 658 | |
| 659 | /* |
| 660 | - cleartraverse - recursive cleanup for algorithms that leave tmp ptrs set |
| 661 | ^ static VOID cleartraverse(struct nfa *, struct state *); |
| 662 | */ |
| 663 | static VOID |
| 664 | cleartraverse(nfa, s) |
| 665 | struct nfa *nfa; |
| 666 | struct state *s; |
| 667 | { |
| 668 | struct arc *a; |
| 669 | |
| 670 | if (s->tmp == NULL) |
| 671 | return; |
| 672 | s->tmp = NULL; |
| 673 | |
| 674 | for (a = s->outs; a != NULL; a = a->outchain) |
| 675 | cleartraverse(nfa, a->to); |
| 676 | } |
| 677 | |
| 678 | /* |
| 679 | - specialcolors - fill in special colors for an NFA |
| 680 | ^ static VOID specialcolors(struct nfa *); |
| 681 | */ |
| 682 | static VOID |
| 683 | specialcolors(nfa) |
| 684 | struct nfa *nfa; |
| 685 | { |
| 686 | /* false colors for BOS, BOL, EOS, EOL */ |
| 687 | if (nfa->parent == NULL) { |
| 688 | nfa->bos[0] = pseudocolor(nfa->cm); |
| 689 | nfa->bos[1] = pseudocolor(nfa->cm); |
| 690 | nfa->eos[0] = pseudocolor(nfa->cm); |
| 691 | nfa->eos[1] = pseudocolor(nfa->cm); |
| 692 | } else { |
| 693 | assert(nfa->parent->bos[0] != COLORLESS); |
| 694 | nfa->bos[0] = nfa->parent->bos[0]; |
| 695 | assert(nfa->parent->bos[1] != COLORLESS); |
| 696 | nfa->bos[1] = nfa->parent->bos[1]; |
| 697 | assert(nfa->parent->eos[0] != COLORLESS); |
| 698 | nfa->eos[0] = nfa->parent->eos[0]; |
| 699 | assert(nfa->parent->eos[1] != COLORLESS); |
| 700 | nfa->eos[1] = nfa->parent->eos[1]; |
| 701 | } |
| 702 | } |
| 703 | |
| 704 | /* |
| 705 | - optimize - optimize an NFA |
| 706 | ^ static long optimize(struct nfa *, FILE *); |
| 707 | */ |
| 708 | static long /* re_info bits */ |
| 709 | optimize(nfa, f) |
| 710 | struct nfa *nfa; |
| 711 | FILE *f; /* for debug output; NULL none */ |
| 712 | { |
| 713 | int verbose = (f != NULL) ? 1 : 0; |
| 714 | |
| 715 | if (verbose) |
| 716 | fprintf(f, "\ninitial cleanup:\n"); |
| 717 | cleanup(nfa); /* may simplify situation */ |
| 718 | if (verbose) |
| 719 | dumpnfa(nfa, f); |
| 720 | if (verbose) |
| 721 | fprintf(f, "\nempties:\n"); |
| 722 | fixempties(nfa, f); /* get rid of EMPTY arcs */ |
| 723 | if (verbose) |
| 724 | fprintf(f, "\nconstraints:\n"); |
| 725 | pullback(nfa, f); /* pull back constraints backward */ |
| 726 | pushfwd(nfa, f); /* push fwd constraints forward */ |
| 727 | if (verbose) |
| 728 | fprintf(f, "\nfinal cleanup:\n"); |
| 729 | cleanup(nfa); /* final tidying */ |
| 730 | return analyze(nfa); /* and analysis */ |
| 731 | } |
| 732 | |
| 733 | /* |
| 734 | - pullback - pull back constraints backward to (with luck) eliminate them |
| 735 | ^ static VOID pullback(struct nfa *, FILE *); |
| 736 | */ |
| 737 | static VOID |
| 738 | pullback(nfa, f) |
| 739 | struct nfa *nfa; |
| 740 | FILE *f; /* for debug output; NULL none */ |
| 741 | { |
| 742 | struct state *s; |
| 743 | struct state *nexts; |
| 744 | struct arc *a; |
| 745 | struct arc *nexta; |
| 746 | int progress; |
| 747 | |
| 748 | /* find and pull until there are no more */ |
| 749 | do { |
| 750 | progress = 0; |
| 751 | for (s = nfa->states; s != NULL && !NISERR(); s = nexts) { |
| 752 | nexts = s->next; |
| 753 | for (a = s->outs; a != NULL && !NISERR(); a = nexta) { |
| 754 | nexta = a->outchain; |
| 755 | if (a->type == '^' || a->type == BEHIND) |
| 756 | if (pull(nfa, a)) |
| 757 | progress = 1; |
| 758 | assert(nexta == NULL || s->no != FREESTATE); |
| 759 | } |
| 760 | } |
| 761 | if (progress && f != NULL) |
| 762 | dumpnfa(nfa, f); |
| 763 | } while (progress && !NISERR()); |
| 764 | if (NISERR()) |
| 765 | return; |
| 766 | |
| 767 | for (a = nfa->pre->outs; a != NULL; a = nexta) { |
| 768 | nexta = a->outchain; |
| 769 | if (a->type == '^') { |
| 770 | assert(a->co == 0 || a->co == 1); |
| 771 | newarc(nfa, PLAIN, nfa->bos[a->co], a->from, a->to); |
| 772 | freearc(nfa, a); |
| 773 | } |
| 774 | } |
| 775 | } |
| 776 | |
| 777 | /* |
| 778 | - pull - pull a back constraint backward past its source state |
| 779 | * A significant property of this function is that it deletes at most |
| 780 | * one state -- the constraint's from state -- and only if the constraint |
| 781 | * was that state's last outarc. |
| 782 | ^ static int pull(struct nfa *, struct arc *); |
| 783 | */ |
| 784 | static int /* 0 couldn't, 1 could */ |
| 785 | pull(nfa, con) |
| 786 | struct nfa *nfa; |
| 787 | struct arc *con; |
| 788 | { |
| 789 | struct state *from = con->from; |
| 790 | struct state *to = con->to; |
| 791 | struct arc *a; |
| 792 | struct arc *nexta; |
| 793 | struct state *s; |
| 794 | |
| 795 | if (from == to) { /* circular constraint is pointless */ |
| 796 | freearc(nfa, con); |
| 797 | return 1; |
| 798 | } |
| 799 | if (from->flag) /* can't pull back beyond start */ |
| 800 | return 0; |
| 801 | if (from->nins == 0) { /* unreachable */ |
| 802 | freearc(nfa, con); |
| 803 | return 1; |
| 804 | } |
| 805 | |
| 806 | /* first, clone from state if necessary to avoid other outarcs */ |
| 807 | if (from->nouts > 1) { |
| 808 | s = newstate(nfa); |
| 809 | if (NISERR()) |
| 810 | return 0; |
| 811 | assert(to != from); /* con is not an inarc */ |
| 812 | copyins(nfa, from, s); /* duplicate inarcs */ |
| 813 | cparc(nfa, con, s, to); /* move constraint arc */ |
| 814 | freearc(nfa, con); |
| 815 | from = s; |
| 816 | con = from->outs; |
| 817 | } |
| 818 | assert(from->nouts == 1); |
| 819 | |
| 820 | /* propagate the constraint into the from state's inarcs */ |
| 821 | for (a = from->ins; a != NULL; a = nexta) { |
| 822 | nexta = a->inchain; |
| 823 | switch (combine(con, a)) { |
| 824 | case INCOMPATIBLE: /* destroy the arc */ |
| 825 | freearc(nfa, a); |
| 826 | break; |
| 827 | case SATISFIED: /* no action needed */ |
| 828 | break; |
| 829 | case COMPATIBLE: /* swap the two arcs, more or less */ |
| 830 | s = newstate(nfa); |
| 831 | if (NISERR()) |
| 832 | return 0; |
| 833 | cparc(nfa, a, s, to); /* anticipate move */ |
| 834 | cparc(nfa, con, a->from, s); |
| 835 | if (NISERR()) |
| 836 | return 0; |
| 837 | freearc(nfa, a); |
| 838 | break; |
| 839 | default: |
| 840 | assert(NOTREACHED); |
| 841 | break; |
| 842 | } |
| 843 | } |
| 844 | |
| 845 | /* remaining inarcs, if any, incorporate the constraint */ |
| 846 | moveins(nfa, from, to); |
| 847 | dropstate(nfa, from); /* will free the constraint */ |
| 848 | return 1; |
| 849 | } |
| 850 | |
| 851 | /* |
| 852 | - pushfwd - push forward constraints forward to (with luck) eliminate them |
| 853 | ^ static VOID pushfwd(struct nfa *, FILE *); |
| 854 | */ |
| 855 | static VOID |
| 856 | pushfwd(nfa, f) |
| 857 | struct nfa *nfa; |
| 858 | FILE *f; /* for debug output; NULL none */ |
| 859 | { |
| 860 | struct state *s; |
| 861 | struct state *nexts; |
| 862 | struct arc *a; |
| 863 | struct arc *nexta; |
| 864 | int progress; |
| 865 | |
| 866 | /* find and push until there are no more */ |
| 867 | do { |
| 868 | progress = 0; |
| 869 | for (s = nfa->states; s != NULL && !NISERR(); s = nexts) { |
| 870 | nexts = s->next; |
| 871 | for (a = s->ins; a != NULL && !NISERR(); a = nexta) { |
| 872 | nexta = a->inchain; |
| 873 | if (a->type == '$' || a->type == AHEAD) |
| 874 | if (push(nfa, a)) |
| 875 | progress = 1; |
| 876 | assert(nexta == NULL || s->no != FREESTATE); |
| 877 | } |
| 878 | } |
| 879 | if (progress && f != NULL) |
| 880 | dumpnfa(nfa, f); |
| 881 | } while (progress && !NISERR()); |
| 882 | if (NISERR()) |
| 883 | return; |
| 884 | |
| 885 | for (a = nfa->post->ins; a != NULL; a = nexta) { |
| 886 | nexta = a->inchain; |
| 887 | if (a->type == '$') { |
| 888 | assert(a->co == 0 || a->co == 1); |
| 889 | newarc(nfa, PLAIN, nfa->eos[a->co], a->from, a->to); |
| 890 | freearc(nfa, a); |
| 891 | } |
| 892 | } |
| 893 | } |
| 894 | |
| 895 | /* |
| 896 | - push - push a forward constraint forward past its destination state |
| 897 | * A significant property of this function is that it deletes at most |
| 898 | * one state -- the constraint's to state -- and only if the constraint |
| 899 | * was that state's last inarc. |
| 900 | ^ static int push(struct nfa *, struct arc *); |
| 901 | */ |
| 902 | static int /* 0 couldn't, 1 could */ |
| 903 | push(nfa, con) |
| 904 | struct nfa *nfa; |
| 905 | struct arc *con; |
| 906 | { |
| 907 | struct state *from = con->from; |
| 908 | struct state *to = con->to; |
| 909 | struct arc *a; |
| 910 | struct arc *nexta; |
| 911 | struct state *s; |
| 912 | |
| 913 | if (to == from) { /* circular constraint is pointless */ |
| 914 | freearc(nfa, con); |
| 915 | return 1; |
| 916 | } |
| 917 | if (to->flag) /* can't push forward beyond end */ |
| 918 | return 0; |
| 919 | if (to->nouts == 0) { /* dead end */ |
| 920 | freearc(nfa, con); |
| 921 | return 1; |
| 922 | } |
| 923 | |
| 924 | /* first, clone to state if necessary to avoid other inarcs */ |
| 925 | if (to->nins > 1) { |
| 926 | s = newstate(nfa); |
| 927 | if (NISERR()) |
| 928 | return 0; |
| 929 | copyouts(nfa, to, s); /* duplicate outarcs */ |
| 930 | cparc(nfa, con, from, s); /* move constraint */ |
| 931 | freearc(nfa, con); |
| 932 | to = s; |
| 933 | con = to->ins; |
| 934 | } |
| 935 | assert(to->nins == 1); |
| 936 | |
| 937 | /* propagate the constraint into the to state's outarcs */ |
| 938 | for (a = to->outs; a != NULL; a = nexta) { |
| 939 | nexta = a->outchain; |
| 940 | switch (combine(con, a)) { |
| 941 | case INCOMPATIBLE: /* destroy the arc */ |
| 942 | freearc(nfa, a); |
| 943 | break; |
| 944 | case SATISFIED: /* no action needed */ |
| 945 | break; |
| 946 | case COMPATIBLE: /* swap the two arcs, more or less */ |
| 947 | s = newstate(nfa); |
| 948 | if (NISERR()) |
| 949 | return 0; |
| 950 | cparc(nfa, con, s, a->to); /* anticipate move */ |
| 951 | cparc(nfa, a, from, s); |
| 952 | if (NISERR()) |
| 953 | return 0; |
| 954 | freearc(nfa, a); |
| 955 | break; |
| 956 | default: |
| 957 | assert(NOTREACHED); |
| 958 | break; |
| 959 | } |
| 960 | } |
| 961 | |
| 962 | /* remaining outarcs, if any, incorporate the constraint */ |
| 963 | moveouts(nfa, to, from); |
| 964 | dropstate(nfa, to); /* will free the constraint */ |
| 965 | return 1; |
| 966 | } |
| 967 | |
| 968 | /* |
| 969 | - combine - constraint lands on an arc, what happens? |
| 970 | ^ #def INCOMPATIBLE 1 // destroys arc |
| 971 | ^ #def SATISFIED 2 // constraint satisfied |
| 972 | ^ #def COMPATIBLE 3 // compatible but not satisfied yet |
| 973 | ^ static int combine(struct arc *, struct arc *); |
| 974 | */ |
| 975 | |
| 976 | /* FIXME Required for CW 8 on Mac since it's not in limits.h */ |
| 977 | #ifndef __CHAR_BIT__ |
| 978 | #define __CHAR_BIT__ 8 |
| 979 | #endif |
| 980 | |
| 981 | |
| 982 | static int |
| 983 | combine(con, a) |
| 984 | struct arc *con; |
| 985 | struct arc *a; |
| 986 | { |
| 987 | # define CA(ct,at) (((ct)<<CHAR_BIT) | (at)) |
| 988 | |
| 989 | switch (CA(con->type, a->type)) { |
| 990 | case CA('^', PLAIN): /* newlines are handled separately */ |
| 991 | case CA('$', PLAIN): |
| 992 | return INCOMPATIBLE; |
| 993 | break; |
| 994 | case CA(AHEAD, PLAIN): /* color constraints meet colors */ |
| 995 | case CA(BEHIND, PLAIN): |
| 996 | if (con->co == a->co) |
| 997 | return SATISFIED; |
| 998 | return INCOMPATIBLE; |
| 999 | break; |
| 1000 | case CA('^', '^'): /* collision, similar constraints */ |
| 1001 | case CA('$', '$'): |
| 1002 | case CA(AHEAD, AHEAD): |
| 1003 | case CA(BEHIND, BEHIND): |
| 1004 | if (con->co == a->co) /* true duplication */ |
| 1005 | return SATISFIED; |
| 1006 | return INCOMPATIBLE; |
| 1007 | break; |
| 1008 | case CA('^', BEHIND): /* collision, dissimilar constraints */ |
| 1009 | case CA(BEHIND, '^'): |
| 1010 | case CA('$', AHEAD): |
| 1011 | case CA(AHEAD, '$'): |
| 1012 | return INCOMPATIBLE; |
| 1013 | break; |
| 1014 | case CA('^', '$'): /* constraints passing each other */ |
| 1015 | case CA('^', AHEAD): |
| 1016 | case CA(BEHIND, '$'): |
| 1017 | case CA(BEHIND, AHEAD): |
| 1018 | case CA('$', '^'): |
| 1019 | case CA('$', BEHIND): |
| 1020 | case CA(AHEAD, '^'): |
| 1021 | case CA(AHEAD, BEHIND): |
| 1022 | case CA('^', LACON): |
| 1023 | case CA(BEHIND, LACON): |
| 1024 | case CA('$', LACON): |
| 1025 | case CA(AHEAD, LACON): |
| 1026 | return COMPATIBLE; |
| 1027 | break; |
| 1028 | } |
| 1029 | assert(NOTREACHED); |
| 1030 | return INCOMPATIBLE; /* for benefit of blind compilers */ |
| 1031 | } |
| 1032 | |
| 1033 | /* |
| 1034 | - fixempties - get rid of EMPTY arcs |
| 1035 | ^ static VOID fixempties(struct nfa *, FILE *); |
| 1036 | */ |
| 1037 | static VOID |
| 1038 | fixempties(nfa, f) |
| 1039 | struct nfa *nfa; |
| 1040 | FILE *f; /* for debug output; NULL none */ |
| 1041 | { |
| 1042 | struct state *s; |
| 1043 | struct state *nexts; |
| 1044 | struct arc *a; |
| 1045 | struct arc *nexta; |
| 1046 | int progress; |
| 1047 | |
| 1048 | /* find and eliminate empties until there are no more */ |
| 1049 | do { |
| 1050 | progress = 0; |
| 1051 | for (s = nfa->states; s != NULL && !NISERR(); s = nexts) { |
| 1052 | nexts = s->next; |
| 1053 | for (a = s->outs; a != NULL && !NISERR(); a = nexta) { |
| 1054 | nexta = a->outchain; |
| 1055 | if (a->type == EMPTY && unempty(nfa, a)) |
| 1056 | progress = 1; |
| 1057 | assert(nexta == NULL || s->no != FREESTATE); |
| 1058 | } |
| 1059 | } |
| 1060 | if (progress && f != NULL) |
| 1061 | dumpnfa(nfa, f); |
| 1062 | } while (progress && !NISERR()); |
| 1063 | } |
| 1064 | |
| 1065 | /* |
| 1066 | - unempty - optimize out an EMPTY arc, if possible |
| 1067 | * Actually, as it stands this function always succeeds, but the return |
| 1068 | * value is kept with an eye on possible future changes. |
| 1069 | ^ static int unempty(struct nfa *, struct arc *); |
| 1070 | */ |
| 1071 | static int /* 0 couldn't, 1 could */ |
| 1072 | unempty(nfa, a) |
| 1073 | struct nfa *nfa; |
| 1074 | struct arc *a; |
| 1075 | { |
| 1076 | struct state *from = a->from; |
| 1077 | struct state *to = a->to; |
| 1078 | int usefrom; /* work on from, as opposed to to? */ |
| 1079 | |
| 1080 | assert(a->type == EMPTY); |
| 1081 | assert(from != nfa->pre && to != nfa->post); |
| 1082 | |
| 1083 | if (from == to) { /* vacuous loop */ |
| 1084 | freearc(nfa, a); |
| 1085 | return 1; |
| 1086 | } |
| 1087 | |
| 1088 | /* decide which end to work on */ |
| 1089 | usefrom = 1; /* default: attack from */ |
| 1090 | if (from->nouts > to->nins) |
| 1091 | usefrom = 0; |
| 1092 | else if (from->nouts == to->nins) { |
| 1093 | /* decide on secondary issue: move/copy fewest arcs */ |
| 1094 | if (from->nins > to->nouts) |
| 1095 | usefrom = 0; |
| 1096 | } |
| 1097 | |
| 1098 | freearc(nfa, a); |
| 1099 | if (usefrom) { |
| 1100 | if (from->nouts == 0) { |
| 1101 | /* was the state's only outarc */ |
| 1102 | moveins(nfa, from, to); |
| 1103 | freestate(nfa, from); |
| 1104 | } else |
| 1105 | copyins(nfa, from, to); |
| 1106 | } else { |
| 1107 | if (to->nins == 0) { |
| 1108 | /* was the state's only inarc */ |
| 1109 | moveouts(nfa, to, from); |
| 1110 | freestate(nfa, to); |
| 1111 | } else |
| 1112 | copyouts(nfa, to, from); |
| 1113 | } |
| 1114 | |
| 1115 | return 1; |
| 1116 | } |
| 1117 | |
| 1118 | /* |
| 1119 | - cleanup - clean up NFA after optimizations |
| 1120 | ^ static VOID cleanup(struct nfa *); |
| 1121 | */ |
| 1122 | static VOID |
| 1123 | cleanup(nfa) |
| 1124 | struct nfa *nfa; |
| 1125 | { |
| 1126 | struct state *s; |
| 1127 | struct state *nexts; |
| 1128 | int n; |
| 1129 | |
| 1130 | /* clear out unreachable or dead-end states */ |
| 1131 | /* use pre to mark reachable, then post to mark can-reach-post */ |
| 1132 | markreachable(nfa, nfa->pre, (struct state *)NULL, nfa->pre); |
| 1133 | markcanreach(nfa, nfa->post, nfa->pre, nfa->post); |
| 1134 | for (s = nfa->states; s != NULL; s = nexts) { |
| 1135 | nexts = s->next; |
| 1136 | if (s->tmp != nfa->post && !s->flag) |
| 1137 | dropstate(nfa, s); |
| 1138 | } |
| 1139 | assert(nfa->post->nins == 0 || nfa->post->tmp == nfa->post); |
| 1140 | cleartraverse(nfa, nfa->pre); |
| 1141 | assert(nfa->post->nins == 0 || nfa->post->tmp == NULL); |
| 1142 | /* the nins==0 (final unreachable) case will be caught later */ |
| 1143 | |
| 1144 | /* renumber surviving states */ |
| 1145 | n = 0; |
| 1146 | for (s = nfa->states; s != NULL; s = s->next) |
| 1147 | s->no = n++; |
| 1148 | nfa->nstates = n; |
| 1149 | } |
| 1150 | |
| 1151 | /* |
| 1152 | - markreachable - recursive marking of reachable states |
| 1153 | ^ static VOID markreachable(struct nfa *, struct state *, struct state *, |
| 1154 | ^ struct state *); |
| 1155 | */ |
| 1156 | static VOID |
| 1157 | markreachable(nfa, s, okay, mark) |
| 1158 | struct nfa *nfa; |
| 1159 | struct state *s; |
| 1160 | struct state *okay; /* consider only states with this mark */ |
| 1161 | struct state *mark; /* the value to mark with */ |
| 1162 | { |
| 1163 | struct arc *a; |
| 1164 | |
| 1165 | if (s->tmp != okay) |
| 1166 | return; |
| 1167 | s->tmp = mark; |
| 1168 | |
| 1169 | for (a = s->outs; a != NULL; a = a->outchain) |
| 1170 | markreachable(nfa, a->to, okay, mark); |
| 1171 | } |
| 1172 | |
| 1173 | /* |
| 1174 | - markcanreach - recursive marking of states which can reach here |
| 1175 | ^ static VOID markcanreach(struct nfa *, struct state *, struct state *, |
| 1176 | ^ struct state *); |
| 1177 | */ |
| 1178 | static VOID |
| 1179 | markcanreach(nfa, s, okay, mark) |
| 1180 | struct nfa *nfa; |
| 1181 | struct state *s; |
| 1182 | struct state *okay; /* consider only states with this mark */ |
| 1183 | struct state *mark; /* the value to mark with */ |
| 1184 | { |
| 1185 | struct arc *a; |
| 1186 | |
| 1187 | if (s->tmp != okay) |
| 1188 | return; |
| 1189 | s->tmp = mark; |
| 1190 | |
| 1191 | for (a = s->ins; a != NULL; a = a->inchain) |
| 1192 | markcanreach(nfa, a->from, okay, mark); |
| 1193 | } |
| 1194 | |
| 1195 | /* |
| 1196 | - analyze - ascertain potentially-useful facts about an optimized NFA |
| 1197 | ^ static long analyze(struct nfa *); |
| 1198 | */ |
| 1199 | static long /* re_info bits to be ORed in */ |
| 1200 | analyze(nfa) |
| 1201 | struct nfa *nfa; |
| 1202 | { |
| 1203 | struct arc *a; |
| 1204 | struct arc *aa; |
| 1205 | |
| 1206 | if (nfa->pre->outs == NULL) |
| 1207 | return REG_UIMPOSSIBLE; |
| 1208 | for (a = nfa->pre->outs; a != NULL; a = a->outchain) |
| 1209 | for (aa = a->to->outs; aa != NULL; aa = aa->outchain) |
| 1210 | if (aa->to == nfa->post) |
| 1211 | return REG_UEMPTYMATCH; |
| 1212 | return 0; |
| 1213 | } |
| 1214 | |
| 1215 | /* |
| 1216 | - compact - compact an NFA |
| 1217 | ^ static VOID compact(struct nfa *, struct cnfa *); |
| 1218 | */ |
| 1219 | static VOID |
| 1220 | compact(nfa, cnfa) |
| 1221 | struct nfa *nfa; |
| 1222 | struct cnfa *cnfa; |
| 1223 | { |
| 1224 | struct state *s; |
| 1225 | struct arc *a; |
| 1226 | size_t nstates; |
| 1227 | size_t narcs; |
| 1228 | struct carc *ca; |
| 1229 | struct carc *first; |
| 1230 | |
| 1231 | assert (!NISERR()); |
| 1232 | |
| 1233 | nstates = 0; |
| 1234 | narcs = 0; |
| 1235 | for (s = nfa->states; s != NULL; s = s->next) { |
| 1236 | nstates++; |
| 1237 | narcs += 1 + s->nouts + 1; |
| 1238 | /* 1 as a fake for flags, nouts for arcs, 1 as endmarker */ |
| 1239 | } |
| 1240 | |
| 1241 | cnfa->states = (struct carc **)MALLOC(nstates * sizeof(struct carc *)); |
| 1242 | cnfa->arcs = (struct carc *)MALLOC(narcs * sizeof(struct carc)); |
| 1243 | if (cnfa->states == NULL || cnfa->arcs == NULL) { |
| 1244 | if (cnfa->states != NULL) |
| 1245 | FREE(cnfa->states); |
| 1246 | if (cnfa->arcs != NULL) |
| 1247 | FREE(cnfa->arcs); |
| 1248 | NERR(REG_ESPACE); |
| 1249 | return; |
| 1250 | } |
| 1251 | cnfa->nstates = nstates; |
| 1252 | cnfa->pre = nfa->pre->no; |
| 1253 | cnfa->post = nfa->post->no; |
| 1254 | cnfa->bos[0] = nfa->bos[0]; |
| 1255 | cnfa->bos[1] = nfa->bos[1]; |
| 1256 | cnfa->eos[0] = nfa->eos[0]; |
| 1257 | cnfa->eos[1] = nfa->eos[1]; |
| 1258 | cnfa->ncolors = maxcolor(nfa->cm) + 1; |
| 1259 | cnfa->flags = 0; |
| 1260 | |
| 1261 | ca = cnfa->arcs; |
| 1262 | for (s = nfa->states; s != NULL; s = s->next) { |
| 1263 | assert((size_t)s->no < nstates); |
| 1264 | cnfa->states[s->no] = ca; |
| 1265 | ca->co = 0; /* clear and skip flags "arc" */ |
| 1266 | ca++; |
| 1267 | first = ca; |
| 1268 | for (a = s->outs; a != NULL; a = a->outchain) |
| 1269 | switch (a->type) { |
| 1270 | case PLAIN: |
| 1271 | ca->co = a->co; |
| 1272 | ca->to = a->to->no; |
| 1273 | ca++; |
| 1274 | break; |
| 1275 | case LACON: |
| 1276 | assert(s->no != cnfa->pre); |
| 1277 | ca->co = (color)(cnfa->ncolors + a->co); |
| 1278 | ca->to = a->to->no; |
| 1279 | ca++; |
| 1280 | cnfa->flags |= HASLACONS; |
| 1281 | break; |
| 1282 | default: |
| 1283 | assert(NOTREACHED); |
| 1284 | break; |
| 1285 | } |
| 1286 | carcsort(first, ca-1); |
| 1287 | ca->co = COLORLESS; |
| 1288 | ca->to = 0; |
| 1289 | ca++; |
| 1290 | } |
| 1291 | assert(ca == &cnfa->arcs[narcs]); |
| 1292 | assert(cnfa->nstates != 0); |
| 1293 | |
| 1294 | /* mark no-progress states */ |
| 1295 | for (a = nfa->pre->outs; a != NULL; a = a->outchain) |
| 1296 | cnfa->states[a->to->no]->co = 1; |
| 1297 | cnfa->states[nfa->pre->no]->co = 1; |
| 1298 | } |
| 1299 | |
| 1300 | /* |
| 1301 | - carcsort - sort compacted-NFA arcs by color |
| 1302 | * Really dumb algorithm, but if the list is long enough for that to matter, |
| 1303 | * you're in real trouble anyway. |
| 1304 | ^ static VOID carcsort(struct carc *, struct carc *); |
| 1305 | */ |
| 1306 | static VOID |
| 1307 | carcsort(first, last) |
| 1308 | struct carc *first; |
| 1309 | struct carc *last; |
| 1310 | { |
| 1311 | struct carc *p; |
| 1312 | struct carc *q; |
| 1313 | struct carc tmp; |
| 1314 | |
| 1315 | if (last - first <= 1) |
| 1316 | return; |
| 1317 | |
| 1318 | for (p = first; p <= last; p++) |
| 1319 | for (q = p; q <= last; q++) |
| 1320 | if (p->co > q->co || |
| 1321 | (p->co == q->co && p->to > q->to)) { |
| 1322 | assert(p != q); |
| 1323 | tmp = *p; |
| 1324 | *p = *q; |
| 1325 | *q = tmp; |
| 1326 | } |
| 1327 | } |
| 1328 | |
| 1329 | /* |
| 1330 | - freecnfa - free a compacted NFA |
| 1331 | ^ static VOID freecnfa(struct cnfa *); |
| 1332 | */ |
| 1333 | static VOID |
| 1334 | freecnfa(cnfa) |
| 1335 | struct cnfa *cnfa; |
| 1336 | { |
| 1337 | assert(cnfa->nstates != 0); /* not empty already */ |
| 1338 | cnfa->nstates = 0; |
| 1339 | FREE(cnfa->states); |
| 1340 | FREE(cnfa->arcs); |
| 1341 | } |
| 1342 | |
| 1343 | /* |
| 1344 | - dumpnfa - dump an NFA in human-readable form |
| 1345 | ^ static VOID dumpnfa(struct nfa *, FILE *); |
| 1346 | */ |
| 1347 | static VOID |
| 1348 | dumpnfa(nfa, f) |
| 1349 | struct nfa *nfa; |
| 1350 | FILE *f; |
| 1351 | { |
| 1352 | #ifdef REG_DEBUG |
| 1353 | struct state *s; |
| 1354 | |
| 1355 | fprintf(f, "pre %d, post %d", nfa->pre->no, nfa->post->no); |
| 1356 | if (nfa->bos[0] != COLORLESS) |
| 1357 | fprintf(f, ", bos [%ld]", (long)nfa->bos[0]); |
| 1358 | if (nfa->bos[1] != COLORLESS) |
| 1359 | fprintf(f, ", bol [%ld]", (long)nfa->bos[1]); |
| 1360 | if (nfa->eos[0] != COLORLESS) |
| 1361 | fprintf(f, ", eos [%ld]", (long)nfa->eos[0]); |
| 1362 | if (nfa->eos[1] != COLORLESS) |
| 1363 | fprintf(f, ", eol [%ld]", (long)nfa->eos[1]); |
| 1364 | fprintf(f, "\n"); |
| 1365 | for (s = nfa->states; s != NULL; s = s->next) |
| 1366 | dumpstate(s, f); |
| 1367 | if (nfa->parent == NULL) |
| 1368 | dumpcolors(nfa->cm, f); |
| 1369 | fflush(f); |
| 1370 | #endif |
| 1371 | } |
| 1372 | |
| 1373 | #ifdef REG_DEBUG /* subordinates of dumpnfa */ |
| 1374 | /* |
| 1375 | ^ #ifdef REG_DEBUG |
| 1376 | */ |
| 1377 | |
| 1378 | /* |
| 1379 | - dumpstate - dump an NFA state in human-readable form |
| 1380 | ^ static VOID dumpstate(struct state *, FILE *); |
| 1381 | */ |
| 1382 | static VOID |
| 1383 | dumpstate(s, f) |
| 1384 | struct state *s; |
| 1385 | FILE *f; |
| 1386 | { |
| 1387 | struct arc *a; |
| 1388 | |
| 1389 | fprintf(f, "%d%s%c", s->no, (s->tmp != NULL) ? "T" : "", |
| 1390 | (s->flag) ? s->flag : '.'); |
| 1391 | if (s->prev != NULL && s->prev->next != s) |
| 1392 | fprintf(f, "\tstate chain bad\n"); |
| 1393 | if (s->nouts == 0) |
| 1394 | fprintf(f, "\tno out arcs\n"); |
| 1395 | else |
| 1396 | dumparcs(s, f); |
| 1397 | fflush(f); |
| 1398 | for (a = s->ins; a != NULL; a = a->inchain) { |
| 1399 | if (a->to != s) |
| 1400 | fprintf(f, "\tlink from %d to %d on %d's in-chain\n", |
| 1401 | a->from->no, a->to->no, s->no); |
| 1402 | } |
| 1403 | } |
| 1404 | |
| 1405 | /* |
| 1406 | - dumparcs - dump out-arcs in human-readable form |
| 1407 | ^ static VOID dumparcs(struct state *, FILE *); |
| 1408 | */ |
| 1409 | static VOID |
| 1410 | dumparcs(s, f) |
| 1411 | struct state *s; |
| 1412 | FILE *f; |
| 1413 | { |
| 1414 | int pos; |
| 1415 | |
| 1416 | assert(s->nouts > 0); |
| 1417 | /* printing arcs in reverse order is usually clearer */ |
| 1418 | pos = dumprarcs(s->outs, s, f, 1); |
| 1419 | if (pos != 1) |
| 1420 | fprintf(f, "\n"); |
| 1421 | } |
| 1422 | |
| 1423 | /* |
| 1424 | - dumprarcs - dump remaining outarcs, recursively, in reverse order |
| 1425 | ^ static int dumprarcs(struct arc *, struct state *, FILE *, int); |
| 1426 | */ |
| 1427 | static int /* resulting print position */ |
| 1428 | dumprarcs(a, s, f, pos) |
| 1429 | struct arc *a; |
| 1430 | struct state *s; |
| 1431 | FILE *f; |
| 1432 | int pos; /* initial print position */ |
| 1433 | { |
| 1434 | if (a->outchain != NULL) |
| 1435 | pos = dumprarcs(a->outchain, s, f, pos); |
| 1436 | dumparc(a, s, f); |
| 1437 | if (pos == 5) { |
| 1438 | fprintf(f, "\n"); |
| 1439 | pos = 1; |
| 1440 | } else |
| 1441 | pos++; |
| 1442 | return pos; |
| 1443 | } |
| 1444 | |
| 1445 | /* |
| 1446 | - dumparc - dump one outarc in readable form, including prefixing tab |
| 1447 | ^ static VOID dumparc(struct arc *, struct state *, FILE *); |
| 1448 | */ |
| 1449 | static VOID |
| 1450 | dumparc(a, s, f) |
| 1451 | struct arc *a; |
| 1452 | struct state *s; |
| 1453 | FILE *f; |
| 1454 | { |
| 1455 | struct arc *aa; |
| 1456 | struct arcbatch *ab; |
| 1457 | |
| 1458 | fprintf(f, "\t"); |
| 1459 | switch (a->type) { |
| 1460 | case PLAIN: |
| 1461 | fprintf(f, "[%ld]", (long)a->co); |
| 1462 | break; |
| 1463 | case AHEAD: |
| 1464 | fprintf(f, ">%ld>", (long)a->co); |
| 1465 | break; |
| 1466 | case BEHIND: |
| 1467 | fprintf(f, "<%ld<", (long)a->co); |
| 1468 | break; |
| 1469 | case LACON: |
| 1470 | fprintf(f, ":%ld:", (long)a->co); |
| 1471 | break; |
| 1472 | case '^': |
| 1473 | case '$': |
| 1474 | fprintf(f, "%c%d", a->type, (int)a->co); |
| 1475 | break; |
| 1476 | case EMPTY: |
| 1477 | break; |
| 1478 | default: |
| 1479 | fprintf(f, "0x%x/0%lo", a->type, (long)a->co); |
| 1480 | break; |
| 1481 | } |
| 1482 | if (a->from != s) |
| 1483 | fprintf(f, "?%d?", a->from->no); |
| 1484 | for (ab = &a->from->oas; ab != NULL; ab = ab->next) { |
| 1485 | for (aa = &ab->a[0]; aa < &ab->a[ABSIZE]; aa++) |
| 1486 | if (aa == a) |
| 1487 | break; /* NOTE BREAK OUT */ |
| 1488 | if (aa < &ab->a[ABSIZE]) /* propagate break */ |
| 1489 | break; /* NOTE BREAK OUT */ |
| 1490 | } |
| 1491 | if (ab == NULL) |
| 1492 | fprintf(f, "?!?"); /* not in allocated space */ |
| 1493 | fprintf(f, "->"); |
| 1494 | if (a->to == NULL) { |
| 1495 | fprintf(f, "NULL"); |
| 1496 | return; |
| 1497 | } |
| 1498 | fprintf(f, "%d", a->to->no); |
| 1499 | for (aa = a->to->ins; aa != NULL; aa = aa->inchain) |
| 1500 | if (aa == a) |
| 1501 | break; /* NOTE BREAK OUT */ |
| 1502 | if (aa == NULL) |
| 1503 | fprintf(f, "?!?"); /* missing from in-chain */ |
| 1504 | } |
| 1505 | |
| 1506 | /* |
| 1507 | ^ #endif |
| 1508 | */ |
| 1509 | #endif /* ifdef REG_DEBUG */ |
| 1510 | |
| 1511 | /* |
| 1512 | - dumpcnfa - dump a compacted NFA in human-readable form |
| 1513 | ^ static VOID dumpcnfa(struct cnfa *, FILE *); |
| 1514 | */ |
| 1515 | static VOID |
| 1516 | dumpcnfa(cnfa, f) |
| 1517 | struct cnfa *cnfa; |
| 1518 | FILE *f; |
| 1519 | { |
| 1520 | #ifdef REG_DEBUG |
| 1521 | int st; |
| 1522 | |
| 1523 | fprintf(f, "pre %d, post %d", cnfa->pre, cnfa->post); |
| 1524 | if (cnfa->bos[0] != COLORLESS) |
| 1525 | fprintf(f, ", bos [%ld]", (long)cnfa->bos[0]); |
| 1526 | if (cnfa->bos[1] != COLORLESS) |
| 1527 | fprintf(f, ", bol [%ld]", (long)cnfa->bos[1]); |
| 1528 | if (cnfa->eos[0] != COLORLESS) |
| 1529 | fprintf(f, ", eos [%ld]", (long)cnfa->eos[0]); |
| 1530 | if (cnfa->eos[1] != COLORLESS) |
| 1531 | fprintf(f, ", eol [%ld]", (long)cnfa->eos[1]); |
| 1532 | if (cnfa->flags&HASLACONS) |
| 1533 | fprintf(f, ", haslacons"); |
| 1534 | fprintf(f, "\n"); |
| 1535 | for (st = 0; st < cnfa->nstates; st++) |
| 1536 | dumpcstate(st, cnfa->states[st], cnfa, f); |
| 1537 | fflush(f); |
| 1538 | #endif |
| 1539 | } |
| 1540 | |
| 1541 | #ifdef REG_DEBUG /* subordinates of dumpcnfa */ |
| 1542 | /* |
| 1543 | ^ #ifdef REG_DEBUG |
| 1544 | */ |
| 1545 | |
| 1546 | /* |
| 1547 | - dumpcstate - dump a compacted-NFA state in human-readable form |
| 1548 | ^ static VOID dumpcstate(int, struct carc *, struct cnfa *, FILE *); |
| 1549 | */ |
| 1550 | static VOID |
| 1551 | dumpcstate(st, ca, cnfa, f) |
| 1552 | int st; |
| 1553 | struct carc *ca; |
| 1554 | struct cnfa *cnfa; |
| 1555 | FILE *f; |
| 1556 | { |
| 1557 | int i; |
| 1558 | int pos; |
| 1559 | |
| 1560 | fprintf(f, "%d%s", st, (ca[0].co) ? ":" : "."); |
| 1561 | pos = 1; |
| 1562 | for (i = 1; ca[i].co != COLORLESS; i++) { |
| 1563 | if (ca[i].co < cnfa->ncolors) |
| 1564 | fprintf(f, "\t[%ld]->%d", (long)ca[i].co, ca[i].to); |
| 1565 | else |
| 1566 | fprintf(f, "\t:%ld:->%d", (long)ca[i].co-cnfa->ncolors, |
| 1567 | ca[i].to); |
| 1568 | if (pos == 5) { |
| 1569 | fprintf(f, "\n"); |
| 1570 | pos = 1; |
| 1571 | } else |
| 1572 | pos++; |
| 1573 | } |
| 1574 | if (i == 1 || pos != 1) |
| 1575 | fprintf(f, "\n"); |
| 1576 | fflush(f); |
| 1577 | } |
| 1578 | |
| 1579 | /* |
| 1580 | ^ #endif |
| 1581 | */ |
| 1582 | #endif /* ifdef REG_DEBUG */ |