regcomp.c (9706B)
1 /* From libregexp but leaks extra classes when it runs out */ 2 3 4 #include <u.h> 5 #include <libc.h> 6 #include "regexp.h" 7 #include "/sys/src/libregexp/regcomp.h" 8 9 #define TRUE 1 10 #define FALSE 0 11 12 /* 13 * Parser Information 14 */ 15 typedef 16 struct Node 17 { 18 Reinst* first; 19 Reinst* last; 20 }Node; 21 22 #define NSTACK 20 23 static Node andstack[NSTACK]; 24 static Node *andp; 25 static int atorstack[NSTACK]; 26 static int* atorp; 27 static int cursubid; /* id of current subexpression */ 28 static int subidstack[NSTACK]; /* parallel to atorstack */ 29 static int* subidp; 30 static int lastwasand; /* Last token was operand */ 31 static int nbra; 32 static char* exprp; /* pointer to next character in source expression */ 33 static int lexdone; 34 static int nclass; 35 static Reclass*classp; 36 static Reinst* freep; 37 static int errors; 38 static Rune yyrune; /* last lex'd rune */ 39 static Reclass*yyclassp; /* last lex'd class */ 40 41 /* predeclared crap */ 42 static void operator(int); 43 static void pushand(Reinst*, Reinst*); 44 static void pushator(int); 45 static void evaluntil(int); 46 static int bldcclass(void); 47 48 static jmp_buf regkaboom; 49 50 static void 51 rcerror(char *s) 52 { 53 errors++; 54 regerror(s); 55 longjmp(regkaboom, 1); 56 } 57 58 static Reinst* 59 newinst(int t) 60 { 61 freep->type = t; 62 freep->left = 0; 63 freep->right = 0; 64 return freep++; 65 } 66 67 static void 68 operand(int t) 69 { 70 Reinst *i; 71 72 if(lastwasand) 73 operator(CAT); /* catenate is implicit */ 74 i = newinst(t); 75 76 if(t == CCLASS || t == NCCLASS) 77 i->cp = yyclassp; 78 if(t == RUNE) 79 i->r = yyrune; 80 81 pushand(i, i); 82 lastwasand = TRUE; 83 } 84 85 static void 86 operator(int t) 87 { 88 if(t==RBRA && --nbra<0) 89 rcerror("unmatched right paren"); 90 if(t==LBRA){ 91 if(++cursubid >= NSUBEXP) 92 rcerror ("too many subexpressions"); 93 nbra++; 94 if(lastwasand) 95 operator(CAT); 96 } else 97 evaluntil(t); 98 if(t != RBRA) 99 pushator(t); 100 lastwasand = FALSE; 101 if(t==STAR || t==QUEST || t==PLUS || t==RBRA) 102 lastwasand = TRUE; /* these look like operands */ 103 } 104 105 static void 106 regerr2(char *s, int c) 107 { 108 char buf[100]; 109 char *cp = buf; 110 while(*s) 111 *cp++ = *s++; 112 *cp++ = c; 113 *cp = '\0'; 114 rcerror(buf); 115 } 116 117 static void 118 cant(char *s) 119 { 120 char buf[100]; 121 strcpy(buf, "can't happen: "); 122 strcat(buf, s); 123 rcerror(buf); 124 } 125 126 static void 127 pushand(Reinst *f, Reinst *l) 128 { 129 if(andp >= &andstack[NSTACK]) 130 cant("operand stack overflow"); 131 andp->first = f; 132 andp->last = l; 133 andp++; 134 } 135 136 static void 137 pushator(int t) 138 { 139 if(atorp >= &atorstack[NSTACK]) 140 cant("operator stack overflow"); 141 *atorp++ = t; 142 *subidp++ = cursubid; 143 } 144 145 static Node* 146 popand(int op) 147 { 148 Reinst *inst; 149 150 if(andp <= &andstack[0]){ 151 regerr2("missing operand for ", op); 152 inst = newinst(NOP); 153 pushand(inst,inst); 154 } 155 return --andp; 156 } 157 158 static int 159 popator(void) 160 { 161 if(atorp <= &atorstack[0]) 162 cant("operator stack underflow"); 163 --subidp; 164 return *--atorp; 165 } 166 167 static void 168 evaluntil(int pri) 169 { 170 Node *op1, *op2; 171 Reinst *inst1, *inst2; 172 173 while(pri==RBRA || atorp[-1]>=pri){ 174 switch(popator()){ 175 default: 176 rcerror("unknown operator in evaluntil"); 177 break; 178 case LBRA: /* must have been RBRA */ 179 op1 = popand('('); 180 inst2 = newinst(RBRA); 181 inst2->subid = *subidp; 182 op1->last->next = inst2; 183 inst1 = newinst(LBRA); 184 inst1->subid = *subidp; 185 inst1->next = op1->first; 186 pushand(inst1, inst2); 187 return; 188 case OR: 189 op2 = popand('|'); 190 op1 = popand('|'); 191 inst2 = newinst(NOP); 192 op2->last->next = inst2; 193 op1->last->next = inst2; 194 inst1 = newinst(OR); 195 inst1->right = op1->first; 196 inst1->left = op2->first; 197 pushand(inst1, inst2); 198 break; 199 case CAT: 200 op2 = popand(0); 201 op1 = popand(0); 202 op1->last->next = op2->first; 203 pushand(op1->first, op2->last); 204 break; 205 case STAR: 206 op2 = popand('*'); 207 inst1 = newinst(OR); 208 op2->last->next = inst1; 209 inst1->right = op2->first; 210 pushand(inst1, inst1); 211 break; 212 case PLUS: 213 op2 = popand('+'); 214 inst1 = newinst(OR); 215 op2->last->next = inst1; 216 inst1->right = op2->first; 217 pushand(op2->first, inst1); 218 break; 219 case QUEST: 220 op2 = popand('?'); 221 inst1 = newinst(OR); 222 inst2 = newinst(NOP); 223 inst1->left = inst2; 224 inst1->right = op2->first; 225 op2->last->next = inst2; 226 pushand(inst1, inst2); 227 break; 228 } 229 } 230 } 231 232 static Reprog* 233 optimize(Reprog *pp) 234 { 235 Reinst *inst, *target; 236 int size; 237 Reprog *npp; 238 Reclass *cl; 239 int diff; 240 241 /* 242 * get rid of NOOP chains 243 */ 244 for(inst=pp->firstinst; inst->type!=END; inst++){ 245 target = inst->next; 246 while(target->type == NOP) 247 target = target->next; 248 inst->next = target; 249 } 250 251 /* 252 * The original allocation is for an area larger than 253 * necessary. Reallocate to the actual space used 254 * and then relocate the code. 255 */ 256 size = sizeof(Reprog) + (freep - pp->firstinst)*sizeof(Reinst); 257 npp = realloc(pp, size); 258 if(npp==0 || npp==pp) 259 return pp; 260 diff = (char *)npp - (char *)pp; 261 freep = (Reinst *)((char *)freep + diff); 262 for(inst=npp->firstinst; inst<freep; inst++){ 263 switch(inst->type){ 264 case OR: 265 case STAR: 266 case PLUS: 267 case QUEST: 268 *(char **)&inst->right += diff; 269 break; 270 case CCLASS: 271 case NCCLASS: 272 *(char **)&inst->right += diff; 273 cl = inst->cp; 274 *(char **)&cl->end += diff; 275 break; 276 } 277 *(char **)&inst->left += diff; 278 } 279 *(char **)&npp->startinst += diff; 280 return npp; 281 } 282 283 #ifdef DEBUG 284 static void 285 dumpstack(void){ 286 Node *stk; 287 int *ip; 288 289 print("operators\n"); 290 for(ip=atorstack; ip<atorp; ip++) 291 print("0%o\n", *ip); 292 print("operands\n"); 293 for(stk=andstack; stk<andp; stk++) 294 print("0%o\t0%o\n", stk->first->type, stk->last->type); 295 } 296 297 static void 298 dump(Reprog *pp) 299 { 300 Reinst *l; 301 Rune *p; 302 303 l = pp->firstinst; 304 do{ 305 print("%d:\t0%o\t%d\t%d", l-pp->firstinst, l->type, 306 l->left-pp->firstinst, l->right-pp->firstinst); 307 if(l->type == RUNE) 308 print("\t%C\n", l->r); 309 else if(l->type == CCLASS || l->type == NCCLASS){ 310 print("\t["); 311 if(l->type == NCCLASS) 312 print("^"); 313 for(p = l->cp->spans; p < l->cp->end; p += 2) 314 if(p[0] == p[1]) 315 print("%C", p[0]); 316 else 317 print("%C-%C", p[0], p[1]); 318 print("]\n"); 319 } else 320 print("\n"); 321 }while(l++->type); 322 } 323 #endif 324 325 static Reclass* 326 newclass(void) 327 { 328 if(nclass <= 0){ 329 classp = mallocz(128*sizeof(Reclass), 1); 330 if(classp == nil) 331 regerror("out of memory"); 332 nclass = 128; 333 } 334 return &classp[--nclass]; 335 } 336 337 static int 338 nextc(Rune *rp) 339 { 340 if(lexdone){ 341 *rp = 0; 342 return 1; 343 } 344 exprp += chartorune(rp, exprp); 345 if(*rp == L'\\'){ 346 exprp += chartorune(rp, exprp); 347 return 1; 348 } 349 if(*rp == 0) 350 lexdone = 1; 351 return 0; 352 } 353 354 static int 355 lex(int literal, int dot_type) 356 { 357 int quoted; 358 359 quoted = nextc(&yyrune); 360 if(literal || quoted){ 361 if(yyrune == 0) 362 return END; 363 return RUNE; 364 } 365 366 switch(yyrune){ 367 case 0: 368 return END; 369 case L'*': 370 return STAR; 371 case L'?': 372 return QUEST; 373 case L'+': 374 return PLUS; 375 case L'|': 376 return OR; 377 case L'.': 378 return dot_type; 379 case L'(': 380 return LBRA; 381 case L')': 382 return RBRA; 383 case L'^': 384 return BOL; 385 case L'$': 386 return EOL; 387 case L'[': 388 return bldcclass(); 389 } 390 return RUNE; 391 } 392 393 static int 394 bldcclass(void) 395 { 396 int type; 397 Rune r[NCCRUNE]; 398 Rune *p, *ep, *np; 399 Rune rune; 400 int quoted; 401 402 /* we have already seen the '[' */ 403 type = CCLASS; 404 yyclassp = newclass(); 405 406 /* look ahead for negation */ 407 /* SPECIAL CASE!!! negated classes don't match \n */ 408 ep = r; 409 quoted = nextc(&rune); 410 if(!quoted && rune == L'^'){ 411 type = NCCLASS; 412 quoted = nextc(&rune); 413 *ep++ = L'\n'; 414 *ep++ = L'\n'; 415 } 416 417 /* parse class into a set of spans */ 418 for(; ep<&r[NCCRUNE];){ 419 if(rune == 0){ 420 rcerror("malformed '[]'"); 421 return 0; 422 } 423 if(!quoted && rune == L']') 424 break; 425 if(!quoted && rune == L'-'){ 426 if(ep == r){ 427 rcerror("malformed '[]'"); 428 return 0; 429 } 430 quoted = nextc(&rune); 431 if((!quoted && rune == L']') || rune == 0){ 432 rcerror("malformed '[]'"); 433 return 0; 434 } 435 *(ep-1) = rune; 436 } else { 437 *ep++ = rune; 438 *ep++ = rune; 439 } 440 quoted = nextc(&rune); 441 } 442 443 /* sort on span start */ 444 for(p = r; p < ep; p += 2){ 445 for(np = p; np < ep; np += 2) 446 if(*np < *p){ 447 rune = np[0]; 448 np[0] = p[0]; 449 p[0] = rune; 450 rune = np[1]; 451 np[1] = p[1]; 452 p[1] = rune; 453 } 454 } 455 456 /* merge spans */ 457 np = yyclassp->spans; 458 p = r; 459 if(r == ep) 460 yyclassp->end = np; 461 else { 462 np[0] = *p++; 463 np[1] = *p++; 464 for(; p < ep; p += 2) 465 if(p[0] <= np[1]){ 466 if(p[1] > np[1]) 467 np[1] = p[1]; 468 } else { 469 np += 2; 470 np[0] = p[0]; 471 np[1] = p[1]; 472 } 473 yyclassp->end = np+2; 474 } 475 476 return type; 477 } 478 479 static Reprog* 480 regcomp1(char *s, int literal, int dot_type) 481 { 482 int token; 483 Reprog *pp; 484 485 /* get memory for the program */ 486 pp = malloc(sizeof(Reprog) + 6*sizeof(Reinst)*strlen(s)); 487 if(pp == 0){ 488 regerror("out of memory"); 489 return 0; 490 } 491 freep = pp->firstinst; 492 classp = pp->class; 493 errors = 0; 494 495 if(setjmp(regkaboom)) 496 goto out; 497 498 /* go compile the sucker */ 499 lexdone = 0; 500 exprp = s; 501 nclass = NCLASS; 502 nbra = 0; 503 atorp = atorstack; 504 andp = andstack; 505 subidp = subidstack; 506 lastwasand = FALSE; 507 cursubid = 0; 508 509 /* Start with a low priority operator to prime parser */ 510 pushator(START-1); 511 while((token = lex(literal, dot_type)) != END){ 512 if((token&0300) == OPERATOR) 513 operator(token); 514 else 515 operand(token); 516 } 517 518 /* Close with a low priority operator */ 519 evaluntil(START); 520 521 /* Force END */ 522 operand(END); 523 evaluntil(START); 524 #ifdef DEBUG 525 dumpstack(); 526 #endif 527 if(nbra) 528 rcerror("unmatched left paren"); 529 --andp; /* points to first and only operand */ 530 pp->startinst = andp->first; 531 #ifdef DEBUG 532 dump(pp); 533 #endif 534 pp = optimize(pp); 535 #ifdef DEBUG 536 print("start: %d\n", andp->first-pp->firstinst); 537 dump(pp); 538 #endif 539 out: 540 if(errors){ 541 free(pp); 542 pp = 0; 543 } 544 return pp; 545 } 546 547 extern Reprog* 548 regcomp(char *s) 549 { 550 return regcomp1(s, 0, ANY); 551 } 552 553 extern Reprog* 554 regcomplit(char *s) 555 { 556 return regcomp1(s, 1, ANY); 557 } 558 559 extern Reprog* 560 regcompnl(char *s) 561 { 562 return regcomp1(s, 0, ANYNL); 563 }