1/* 2 * DFA routines 3 * This file is #included by regexec.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/* 34 - longest - longest-preferred matching engine 35 ^ static chr *longest(struct vars *, struct dfa *, chr *, chr *, int *); 36 */ 37static chr * /* endpoint, or NULL */ 38longest(v, d, start, stop, hitstopp) 39struct vars *v; /* used only for debug and exec flags */ 40struct dfa *d; 41chr *start; /* where the match should start */ 42chr *stop; /* match must end at or before here */ 43int *hitstopp; /* record whether hit v->stop, if non-NULL */ 44{ 45 chr *cp; 46 chr *realstop = (stop == v->stop) ? stop : stop + 1; 47 color co; 48 struct sset *css; 49 struct sset *ss; 50 chr *post; 51 int i; 52 struct colormap *cm = d->cm; 53 54 /* initialize */ 55 css = initialize(v, d, start); 56 cp = start; 57 if (hitstopp != NULL) 58 *hitstopp = 0; 59 60 /* startup */ 61 FDEBUG(("+++ startup +++\n")); 62 if (cp == v->start) { 63 co = d->cnfa->bos[(v->eflags®_NOTBOL) ? 0 : 1]; 64 FDEBUG(("color %ld\n", (long)co)); 65 } else { 66 co = GETCOLOR(cm, *(cp - 1)); 67 FDEBUG(("char %c, color %ld\n", (char)*(cp-1), (long)co)); 68 } 69 css = miss(v, d, css, co, cp, start); 70 if (css == NULL) 71 return NULL; 72 css->lastseen = cp; 73 74 /* main loop */ 75 if (v->eflags®_FTRACE) 76 while (cp < realstop) { 77 FDEBUG(("+++ at c%d +++\n", css - d->ssets)); 78 co = GETCOLOR(cm, *cp); 79 FDEBUG(("char %c, color %ld\n", (char)*cp, (long)co)); 80 ss = css->outs[co]; 81 if (ss == NULL) { 82 ss = miss(v, d, css, co, cp+1, start); 83 if (ss == NULL) 84 break; /* NOTE BREAK OUT */ 85 } 86 cp++; 87 ss->lastseen = cp; 88 css = ss; 89 } 90 else 91 while (cp < realstop) { 92 co = GETCOLOR(cm, *cp); 93 ss = css->outs[co]; 94 if (ss == NULL) { 95 ss = miss(v, d, css, co, cp+1, start); 96 if (ss == NULL) 97 break; /* NOTE BREAK OUT */ 98 } 99 cp++; 100 ss->lastseen = cp; 101 css = ss; 102 } 103 104 /* shutdown */ 105 FDEBUG(("+++ shutdown at c%d +++\n", css - d->ssets)); 106 if (cp == v->stop && stop == v->stop) { 107 if (hitstopp != NULL) 108 *hitstopp = 1; 109 co = d->cnfa->eos[(v->eflags®_NOTEOL) ? 0 : 1]; 110 FDEBUG(("color %ld\n", (long)co)); 111 ss = miss(v, d, css, co, cp, start); 112 /* special case: match ended at eol? */ 113 if (ss != NULL && (ss->flags&POSTSTATE)) 114 return cp; 115 else if (ss != NULL) 116 ss->lastseen = cp; /* to be tidy */ 117 } 118 119 /* find last match, if any */ 120 post = d->lastpost; 121 for (ss = d->ssets, i = d->nssused; i > 0; ss++, i--) 122 if ((ss->flags&POSTSTATE) && post != ss->lastseen && 123 (post == NULL || post < ss->lastseen)) 124 post = ss->lastseen; 125 if (post != NULL) /* found one */ 126 return post - 1; 127 128 return NULL; 129} 130 131/* 132 - shortest - shortest-preferred matching engine 133 ^ static chr *shortest(struct vars *, struct dfa *, chr *, chr *, chr *, 134 ^ chr **, int *); 135 */ 136static chr * /* endpoint, or NULL */ 137shortest(v, d, start, min, max, coldp, hitstopp) 138struct vars *v; 139struct dfa *d; 140chr *start; /* where the match should start */ 141chr *min; /* match must end at or after here */ 142chr *max; /* match must end at or before here */ 143chr **coldp; /* store coldstart pointer here, if nonNULL */ 144int *hitstopp; /* record whether hit v->stop, if non-NULL */ 145{ 146 chr *cp; 147 chr *realmin = (min == v->stop) ? min : min + 1; 148 chr *realmax = (max == v->stop) ? max : max + 1; 149 color co; 150 struct sset *css; 151 struct sset *ss; 152 struct colormap *cm = d->cm; 153 154 /* initialize */ 155 css = initialize(v, d, start); 156 cp = start; 157 if (hitstopp != NULL) 158 *hitstopp = 0; 159 160 /* startup */ 161 FDEBUG(("--- startup ---\n")); 162 if (cp == v->start) { 163 co = d->cnfa->bos[(v->eflags®_NOTBOL) ? 0 : 1]; 164 FDEBUG(("color %ld\n", (long)co)); 165 } else { 166 co = GETCOLOR(cm, *(cp - 1)); 167 FDEBUG(("char %c, color %ld\n", (char)*(cp-1), (long)co)); 168 } 169 css = miss(v, d, css, co, cp, start); 170 if (css == NULL) 171 return NULL; 172 css->lastseen = cp; 173 ss = css; 174 175 /* main loop */ 176 if (v->eflags®_FTRACE) 177 while (cp < realmax) { 178 FDEBUG(("--- at c%d ---\n", css - d->ssets)); 179 co = GETCOLOR(cm, *cp); 180 FDEBUG(("char %c, color %ld\n", (char)*cp, (long)co)); 181 ss = css->outs[co]; 182 if (ss == NULL) { 183 ss = miss(v, d, css, co, cp+1, start); 184 if (ss == NULL) 185 break; /* NOTE BREAK OUT */ 186 } 187 cp++; 188 ss->lastseen = cp; 189 css = ss; 190 if ((ss->flags&POSTSTATE) && cp >= realmin) 191 break; /* NOTE BREAK OUT */ 192 } 193 else 194 while (cp < realmax) { 195 co = GETCOLOR(cm, *cp); 196 ss = css->outs[co]; 197 if (ss == NULL) { 198 ss = miss(v, d, css, co, cp+1, start); 199 if (ss == NULL) 200 break; /* NOTE BREAK OUT */ 201 } 202 cp++; 203 ss->lastseen = cp; 204 css = ss; 205 if ((ss->flags&POSTSTATE) && cp >= realmin) 206 break; /* NOTE BREAK OUT */ 207 } 208 209 if (ss == NULL) 210 return NULL; 211 212 if (coldp != NULL) /* report last no-progress state set, if any */ 213 *coldp = lastcold(v, d); 214 215 if ((ss->flags&POSTSTATE) && cp > min) { 216 assert(cp >= realmin); 217 cp--; 218 } else if (cp == v->stop && max == v->stop) { 219 co = d->cnfa->eos[(v->eflags®_NOTEOL) ? 0 : 1]; 220 FDEBUG(("color %ld\n", (long)co)); 221 ss = miss(v, d, css, co, cp, start); 222 /* match might have ended at eol */ 223 if ((ss == NULL || !(ss->flags&POSTSTATE)) && hitstopp != NULL) 224 *hitstopp = 1; 225 } 226 227 if (ss == NULL || !(ss->flags&POSTSTATE)) 228 return NULL; 229 230 return cp; 231} 232 233/* 234 - lastcold - determine last point at which no progress had been made 235 ^ static chr *lastcold(struct vars *, struct dfa *); 236 */ 237static chr * /* endpoint, or NULL */ 238lastcold(v, d) 239struct vars *v; 240struct dfa *d; 241{ 242 struct sset *ss; 243 chr *nopr; 244 int i; 245 246 nopr = d->lastnopr; 247 if (nopr == NULL) 248 nopr = v->start; 249 for (ss = d->ssets, i = d->nssused; i > 0; ss++, i--) 250 if ((ss->flags&NOPROGRESS) && nopr < ss->lastseen) 251 nopr = ss->lastseen; 252 return nopr; 253} 254 255/* 256 - newdfa - set up a fresh DFA 257 ^ static struct dfa *newdfa(struct vars *, struct cnfa *, 258 ^ struct colormap *, struct smalldfa *); 259 */ 260 261/* FIXME Required for CW 8 on Mac since it's not in limits.h */ 262#ifndef __CHAR_BIT__ 263#define __CHAR_BIT__ 8 264#endif 265 266static struct dfa * 267newdfa(v, cnfa, cm, small) 268struct vars *v; 269struct cnfa *cnfa; 270struct colormap *cm; 271struct smalldfa *small; /* preallocated space, may be NULL */ 272{ 273 struct dfa *d; 274 size_t nss = cnfa->nstates * 2; 275 int wordsper = (cnfa->nstates + UBITS - 1) / UBITS; 276 struct smalldfa *smallwas = small; 277 278 assert(cnfa != NULL && cnfa->nstates != 0); 279 280 if (nss <= FEWSTATES && cnfa->ncolors <= FEWCOLORS) { 281 assert(wordsper == 1); 282 if (small == NULL) { 283 small = (struct smalldfa *)MALLOC( 284 sizeof(struct smalldfa)); 285 if (small == NULL) { 286 ERR(REG_ESPACE); 287 return NULL; 288 } 289 } 290 d = &small->dfa; 291 d->ssets = small->ssets; 292 d->statesarea = small->statesarea; 293 d->work = &d->statesarea[nss]; 294 d->outsarea = small->outsarea; 295 d->incarea = small->incarea; 296 d->cptsmalloced = 0; 297 d->mallocarea = (smallwas == NULL) ? (char *)small : NULL; 298 } else { 299 d = (struct dfa *)MALLOC(sizeof(struct dfa)); 300 if (d == NULL) { 301 ERR(REG_ESPACE); 302 return NULL; 303 } 304 d->ssets = (struct sset *)MALLOC(nss * sizeof(struct sset)); 305 d->statesarea = (unsigned *)MALLOC((nss+WORK) * wordsper * 306 sizeof(unsigned)); 307 d->work = &d->statesarea[nss * wordsper]; 308 d->outsarea = (struct sset **)MALLOC(nss * cnfa->ncolors * 309 sizeof(struct sset *)); 310 d->incarea = (struct arcp *)MALLOC(nss * cnfa->ncolors * 311 sizeof(struct arcp)); 312 d->cptsmalloced = 1; 313 d->mallocarea = (char *)d; 314 if (d->ssets == NULL || d->statesarea == NULL || 315 d->outsarea == NULL || d->incarea == NULL) { 316 freedfa(d); 317 ERR(REG_ESPACE); 318 return NULL; 319 } 320 } 321 322 d->nssets = (v->eflags®_SMALL) ? 7 : nss; 323 d->nssused = 0; 324 d->nstates = cnfa->nstates; 325 d->ncolors = cnfa->ncolors; 326 d->wordsper = wordsper; 327 d->cnfa = cnfa; 328 d->cm = cm; 329 d->lastpost = NULL; 330 d->lastnopr = NULL; 331 d->search = d->ssets; 332 333 /* initialization of sset fields is done as needed */ 334 335 return d; 336} 337 338/* 339 - freedfa - free a DFA 340 ^ static VOID freedfa(struct dfa *); 341 */ 342static VOID 343freedfa(d) 344struct dfa *d; 345{ 346 if (d->cptsmalloced) { 347 if (d->ssets != NULL) 348 FREE(d->ssets); 349 if (d->statesarea != NULL) 350 FREE(d->statesarea); 351 if (d->outsarea != NULL) 352 FREE(d->outsarea); 353 if (d->incarea != NULL) 354 FREE(d->incarea); 355 } 356 357 if (d->mallocarea != NULL) 358 FREE(d->mallocarea); 359} 360 361/* 362 - hash - construct a hash code for a bitvector 363 * There are probably better ways, but they're more expensive. 364 ^ static unsigned hash(unsigned *, int); 365 */ 366static unsigned 367hash(uv, n) 368unsigned *uv; 369int n; 370{ 371 int i; 372 unsigned h; 373 374 h = 0; 375 for (i = 0; i < n; i++) 376 h ^= uv[i]; 377 return h; 378} 379 380/* 381 - initialize - hand-craft a cache entry for startup, otherwise get ready 382 ^ static struct sset *initialize(struct vars *, struct dfa *, chr *); 383 */ 384static struct sset * 385initialize(v, d, start) 386struct vars *v; /* used only for debug flags */ 387struct dfa *d; 388chr *start; 389{ 390 struct sset *ss; 391 int i; 392 393 /* is previous one still there? */ 394 if (d->nssused > 0 && (d->ssets[0].flags&STARTER)) 395 ss = &d->ssets[0]; 396 else { /* no, must (re)build it */ 397 ss = getvacant(v, d, start, start); 398 for (i = 0; i < d->wordsper; i++) 399 ss->states[i] = 0; 400 BSET(ss->states, d->cnfa->pre); 401 ss->hash = HASH(ss->states, d->wordsper); 402 assert(d->cnfa->pre != d->cnfa->post); 403 ss->flags = STARTER|LOCKED|NOPROGRESS; 404 /* lastseen dealt with below */ 405 } 406 407 for (i = 0; i < d->nssused; i++) 408 d->ssets[i].lastseen = NULL; 409 ss->lastseen = start; /* maybe untrue, but harmless */ 410 d->lastpost = NULL; 411 d->lastnopr = NULL; 412 return ss; 413} 414 415/* 416 - miss - handle a cache miss 417 ^ static struct sset *miss(struct vars *, struct dfa *, struct sset *, 418 ^ pcolor, chr *, chr *); 419 */ 420static struct sset * /* NULL if goes to empty set */ 421miss(v, d, css, co, cp, start) 422struct vars *v; /* used only for debug flags */ 423struct dfa *d; 424struct sset *css; 425pcolor co; 426chr *cp; /* next chr */ 427chr *start; /* where the attempt got started */ 428{ 429 struct cnfa *cnfa = d->cnfa; 430 int i; 431 unsigned h; 432 struct carc *ca; 433 struct sset *p; 434 int ispost; 435 int noprogress; 436 int gotstate; 437 int dolacons; 438 int sawlacons; 439 440 /* for convenience, we can be called even if it might not be a miss */ 441 if (css->outs[co] != NULL) { 442 FDEBUG(("hit\n")); 443 return css->outs[co]; 444 } 445 FDEBUG(("miss\n")); 446 447 /* first, what set of states would we end up in? */ 448 for (i = 0; i < d->wordsper; i++) 449 d->work[i] = 0; 450 ispost = 0; 451 noprogress = 1; 452 gotstate = 0; 453 for (i = 0; i < d->nstates; i++) 454 if (ISBSET(css->states, i)) 455 for (ca = cnfa->states[i]+1; ca->co != COLORLESS; ca++) 456 if (ca->co == co) { 457 BSET(d->work, ca->to); 458 gotstate = 1; 459 if (ca->to == cnfa->post) 460 ispost = 1; 461 if (!cnfa->states[ca->to]->co) 462 noprogress = 0; 463 FDEBUG(("%d -> %d\n", i, ca->to)); 464 } 465 dolacons = (gotstate) ? (cnfa->flags&HASLACONS) : 0; 466 sawlacons = 0; 467 while (dolacons) { /* transitive closure */ 468 dolacons = 0; 469 for (i = 0; i < d->nstates; i++) 470 if (ISBSET(d->work, i)) 471 for (ca = cnfa->states[i]+1; ca->co != COLORLESS; 472 ca++) { 473 if (ca->co <= cnfa->ncolors) 474 continue; /* NOTE CONTINUE */ 475 sawlacons = 1; 476 if (ISBSET(d->work, ca->to)) 477 continue; /* NOTE CONTINUE */ 478 if (!lacon(v, cnfa, cp, ca->co)) 479 continue; /* NOTE CONTINUE */ 480 BSET(d->work, ca->to); 481 dolacons = 1; 482 if (ca->to == cnfa->post) 483 ispost = 1; 484 if (!cnfa->states[ca->to]->co) 485 noprogress = 0; 486 FDEBUG(("%d :> %d\n", i, ca->to)); 487 } 488 } 489 if (!gotstate) 490 return NULL; 491 h = HASH(d->work, d->wordsper); 492 493 /* next, is that in the cache? */ 494 for (p = d->ssets, i = d->nssused; i > 0; p++, i--) 495 if (HIT(h, d->work, p, d->wordsper)) { 496 FDEBUG(("cached c%d\n", p - d->ssets)); 497 break; /* NOTE BREAK OUT */ 498 } 499 if (i == 0) { /* nope, need a new cache entry */ 500 p = getvacant(v, d, cp, start); 501 assert(p != css); 502 for (i = 0; i < d->wordsper; i++) 503 p->states[i] = d->work[i]; 504 p->hash = h; 505 p->flags = (ispost) ? POSTSTATE : 0; 506 if (noprogress) 507 p->flags |= NOPROGRESS; 508 /* lastseen to be dealt with by caller */ 509 } 510 511 if (!sawlacons) { /* lookahead conds. always cache miss */ 512 FDEBUG(("c%d[%d]->c%d\n", css - d->ssets, co, p - d->ssets)); 513 css->outs[co] = p; 514 css->inchain[co] = p->ins; 515 p->ins.ss = css; 516 p->ins.co = (color)co; 517 } 518 return p; 519} 520 521/* 522 - lacon - lookahead-constraint checker for miss() 523 ^ static int lacon(struct vars *, struct cnfa *, chr *, pcolor); 524 */ 525static int /* predicate: constraint satisfied? */ 526lacon(v, pcnfa, cp, co) 527struct vars *v; 528struct cnfa *pcnfa; /* parent cnfa */ 529chr *cp; 530pcolor co; /* "color" of the lookahead constraint */ 531{ 532 int n; 533 struct subre *sub; 534 struct dfa *d; 535 struct smalldfa sd; 536 chr *end; 537 538 n = co - pcnfa->ncolors; 539 assert(n < v->g->nlacons && v->g->lacons != NULL); 540 FDEBUG(("=== testing lacon %d\n", n)); 541 sub = &v->g->lacons[n]; 542 d = newdfa(v, &sub->cnfa, &v->g->cmap, &sd); 543 if (d == NULL) { 544 ERR(REG_ESPACE); 545 return 0; 546 } 547 end = longest(v, d, cp, v->stop, (int *)NULL); 548 freedfa(d); 549 FDEBUG(("=== lacon %d match %d\n", n, (end != NULL))); 550 return (sub->subno) ? (end != NULL) : (end == NULL); 551} 552 553/* 554 - getvacant - get a vacant state set 555 * This routine clears out the inarcs and outarcs, but does not otherwise 556 * clear the innards of the state set -- that's up to the caller. 557 ^ static struct sset *getvacant(struct vars *, struct dfa *, chr *, chr *); 558 */ 559static struct sset * 560getvacant(v, d, cp, start) 561struct vars *v; /* used only for debug flags */ 562struct dfa *d; 563chr *cp; 564chr *start; 565{ 566 int i; 567 struct sset *ss; 568 struct sset *p; 569 struct arcp ap; 570 struct arcp lastap; 571 color co; 572 573 ss = pickss(v, d, cp, start); 574 assert(!(ss->flags&LOCKED)); 575 576 /* clear out its inarcs, including self-referential ones */ 577 ap = ss->ins; 578 while ((p = ap.ss) != NULL) { 579 co = ap.co; 580 FDEBUG(("zapping c%d's %ld outarc\n", p - d->ssets, (long)co)); 581 p->outs[co] = NULL; 582 ap = p->inchain[co]; 583 p->inchain[co].ss = NULL; /* paranoia */ 584 } 585 ss->ins.ss = NULL; 586 587 /* take it off the inarc chains of the ssets reached by its outarcs */ 588 for (i = 0; i < d->ncolors; i++) { 589 p = ss->outs[i]; 590 assert(p != ss); /* not self-referential */ 591 if (p == NULL) 592 continue; /* NOTE CONTINUE */ 593 FDEBUG(("del outarc %d from c%d's in chn\n", i, p - d->ssets)); 594 if (p->ins.ss == ss && p->ins.co == i) 595 p->ins = ss->inchain[i]; 596 else { 597 assert(p->ins.ss != NULL); 598 for (ap = p->ins; ap.ss != NULL && 599 !(ap.ss == ss && ap.co == i); 600 ap = ap.ss->inchain[ap.co]) 601 lastap = ap; 602 assert(ap.ss != NULL); 603 lastap.ss->inchain[lastap.co] = ss->inchain[i]; 604 } 605 ss->outs[i] = NULL; 606 ss->inchain[i].ss = NULL; 607 } 608 609 /* if ss was a success state, may need to remember location */ 610 if ((ss->flags&POSTSTATE) && ss->lastseen != d->lastpost && 611 (d->lastpost == NULL || d->lastpost < ss->lastseen)) 612 d->lastpost = ss->lastseen; 613 614 /* likewise for a no-progress state */ 615 if ((ss->flags&NOPROGRESS) && ss->lastseen != d->lastnopr && 616 (d->lastnopr == NULL || d->lastnopr < ss->lastseen)) 617 d->lastnopr = ss->lastseen; 618 619 return ss; 620} 621 622/* 623 - pickss - pick the next stateset to be used 624 ^ static struct sset *pickss(struct vars *, struct dfa *, chr *, chr *); 625 */ 626static struct sset * 627pickss(v, d, cp, start) 628struct vars *v; /* used only for debug flags */ 629struct dfa *d; 630chr *cp; 631chr *start; 632{ 633 int i; 634 struct sset *ss; 635 struct sset *end; 636 chr *ancient; 637 638 /* shortcut for cases where cache isn't full */ 639 if (d->nssused < d->nssets) { 640 i = d->nssused; 641 d->nssused++; 642 ss = &d->ssets[i]; 643 FDEBUG(("new c%d\n", i)); 644 /* set up innards */ 645 ss->states = &d->statesarea[i * d->wordsper]; 646 ss->flags = 0; 647 ss->ins.ss = NULL; 648 ss->ins.co = WHITE; /* give it some value */ 649 ss->outs = &d->outsarea[i * d->ncolors]; 650 ss->inchain = &d->incarea[i * d->ncolors]; 651 for (i = 0; i < d->ncolors; i++) { 652 ss->outs[i] = NULL; 653 ss->inchain[i].ss = NULL; 654 } 655 return ss; 656 } 657 658 /* look for oldest, or old enough anyway */ 659 if (cp - start > d->nssets*2/3) /* oldest 33% are expendable */ 660 ancient = cp - d->nssets*2/3; 661 else 662 ancient = start; 663 for (ss = d->search, end = &d->ssets[d->nssets]; ss < end; ss++) 664 if ((ss->lastseen == NULL || ss->lastseen < ancient) && 665 !(ss->flags&LOCKED)) { 666 d->search = ss + 1; 667 FDEBUG(("replacing c%d\n", ss - d->ssets)); 668 return ss; 669 } 670 for (ss = d->ssets, end = d->search; ss < end; ss++) 671 if ((ss->lastseen == NULL || ss->lastseen < ancient) && 672 !(ss->flags&LOCKED)) { 673 d->search = ss + 1; 674 FDEBUG(("replacing c%d\n", ss - d->ssets)); 675 return ss; 676 } 677 678 /* nobody's old enough?!? -- something's really wrong */ 679 FDEBUG(("can't find victim to replace!\n")); 680 assert(NOTREACHED); 681 ERR(REG_ASSERT); 682 return d->ssets; 683} 684