Commit | Line | Data |
a687059c |
1 | /* NOTE: this is derived from Henry Spencer's regexp code, and should not |
2 | * confused with the original package (see point 3 below). Thanks, Henry! |
3 | */ |
4 | |
5 | /* Additional note: this code is very heavily munged from Henry's version |
6 | * in places. In some spots I've traded clarity for efficiency, so don't |
7 | * blame Henry for some of the lack of readability. |
8 | */ |
9 | |
ac58e20f |
10 | /* $Header: regexec.c,v 3.0.1.3 90/02/28 18:14:39 lwall Locked $ |
a687059c |
11 | * |
12 | * $Log: regexec.c,v $ |
ac58e20f |
13 | * Revision 3.0.1.3 90/02/28 18:14:39 lwall |
14 | * patch9: /[\200-\377]/ didn't work on machines with signed chars |
15 | * patch9: \d, \w, and \s could misfire on characters with high bit set |
16 | * patch9: /\bfoo/i didn't work |
17 | * |
663a0e37 |
18 | * Revision 3.0.1.2 89/12/21 20:16:27 lwall |
19 | * patch7: certain patterns didn't match correctly at end of string |
20 | * |
ae986130 |
21 | * Revision 3.0.1.1 89/11/11 04:52:04 lwall |
22 | * patch2: /\b$foo/ didn't work |
23 | * |
a687059c |
24 | * Revision 3.0 89/10/18 15:22:53 lwall |
25 | * 3.0 baseline |
26 | * |
27 | */ |
28 | |
29 | /* |
30 | * regcomp and regexec -- regsub and regerror are not used in perl |
31 | * |
32 | * Copyright (c) 1986 by University of Toronto. |
33 | * Written by Henry Spencer. Not derived from licensed software. |
34 | * |
35 | * Permission is granted to anyone to use this software for any |
36 | * purpose on any computer system, and to redistribute it freely, |
37 | * subject to the following restrictions: |
38 | * |
39 | * 1. The author is not responsible for the consequences of use of |
40 | * this software, no matter how awful, even if they arise |
41 | * from defects in it. |
42 | * |
43 | * 2. The origin of this software must not be misrepresented, either |
44 | * by explicit claim or by omission. |
45 | * |
46 | * 3. Altered versions must be plainly marked as such, and must not |
47 | * be misrepresented as being the original software. |
48 | * |
49 | **** Alterations to Henry's code are... |
50 | **** |
51 | **** Copyright (c) 1989, Larry Wall |
52 | **** |
53 | **** You may distribute under the terms of the GNU General Public License |
54 | **** as specified in the README file that comes with the perl 3.0 kit. |
55 | * |
56 | * Beware that some of this code is subtly aware of the way operator |
57 | * precedence is structured in regular expressions. Serious changes in |
58 | * regular-expression syntax might require a total rethink. |
59 | */ |
60 | #include "EXTERN.h" |
61 | #include "perl.h" |
62 | #include "regcomp.h" |
63 | |
64 | #ifndef STATIC |
65 | #define STATIC static |
66 | #endif |
67 | |
68 | #ifdef DEBUGGING |
69 | int regnarrate = 0; |
70 | #endif |
71 | |
ac58e20f |
72 | #define isALNUM(c) (isascii(c) && (isalpha(c) || isdigit(c) || c == '_')) |
73 | #define isSPACE(c) (isascii(c) && isspace(c)) |
74 | #define isDIGIT(c) (isascii(c) && isdigit(c)) |
75 | #define isUPPER(c) (isascii(c) && isupper(c)) |
76 | |
a687059c |
77 | /* |
78 | * regexec and friends |
79 | */ |
80 | |
81 | /* |
82 | * Global work variables for regexec(). |
83 | */ |
84 | static char *regprecomp; |
85 | static char *reginput; /* String-input pointer. */ |
ac58e20f |
86 | static char regprev; /* char before regbol, \n if none */ |
a687059c |
87 | static char *regbol; /* Beginning of input, for ^ check. */ |
88 | static char *regeol; /* End of input, for $ check. */ |
89 | static char **regstartp; /* Pointer to startp array. */ |
90 | static char **regendp; /* Ditto for endp. */ |
91 | static char *reglastparen; /* Similarly for lastparen. */ |
92 | static char *regtill; |
93 | |
94 | static char *regmystartp[10]; /* For remembering backreferences. */ |
95 | static char *regmyendp[10]; |
96 | |
97 | /* |
98 | * Forwards. |
99 | */ |
100 | STATIC int regtry(); |
101 | STATIC int regmatch(); |
102 | STATIC int regrepeat(); |
103 | |
104 | extern int multiline; |
105 | |
106 | /* |
107 | - regexec - match a regexp against a string |
108 | */ |
109 | int |
110 | regexec(prog, stringarg, strend, strbeg, minend, screamer, safebase) |
111 | register regexp *prog; |
112 | char *stringarg; |
113 | register char *strend; /* pointer to null at end of string */ |
114 | char *strbeg; /* real beginning of string */ |
115 | int minend; /* end of match must be at least minend after stringarg */ |
116 | STR *screamer; |
117 | int safebase; /* no need to remember string in subbase */ |
118 | { |
119 | register char *s; |
120 | register int i; |
121 | register char *c; |
122 | register char *string = stringarg; |
123 | register int tmp; |
124 | int minlen = 0; /* must match at least this many chars */ |
125 | int dontbother = 0; /* how many characters not to try at end */ |
a687059c |
126 | |
127 | /* Be paranoid... */ |
128 | if (prog == NULL || string == NULL) { |
129 | fatal("NULL regexp parameter"); |
130 | return(0); |
131 | } |
132 | |
ac58e20f |
133 | if (string == strbeg) /* is ^ valid at stringarg? */ |
134 | regprev = '\n'; |
135 | else |
136 | regprev = stringarg[-1]; |
a687059c |
137 | regprecomp = prog->precomp; |
138 | /* Check validity of program. */ |
139 | if (UCHARAT(prog->program) != MAGIC) { |
140 | FAIL("corrupted regexp program"); |
141 | } |
142 | |
143 | if (prog->do_folding) { |
144 | safebase = FALSE; |
145 | i = strend - string; |
146 | New(1101,c,i+1,char); |
147 | (void)bcopy(string, c, i+1); |
148 | string = c; |
149 | strend = string + i; |
150 | for (s = string; s < strend; s++) |
ac58e20f |
151 | if (isUPPER(*s)) |
a687059c |
152 | *s = tolower(*s); |
153 | } |
154 | |
155 | /* If there is a "must appear" string, look for it. */ |
156 | s = string; |
157 | if (prog->regmust != Nullstr) { |
ac58e20f |
158 | if (stringarg == strbeg && screamer) { |
a687059c |
159 | if (screamfirst[prog->regmust->str_rare] >= 0) |
160 | s = screaminstr(screamer,prog->regmust); |
161 | else |
162 | s = Nullch; |
163 | } |
164 | #ifndef lint |
165 | else |
166 | s = fbminstr((unsigned char*)s, (unsigned char*)strend, |
167 | prog->regmust); |
168 | #endif |
169 | if (!s) { |
170 | ++prog->regmust->str_u.str_useful; /* hooray */ |
171 | goto phooey; /* not present */ |
172 | } |
173 | else if (prog->regback >= 0) { |
174 | s -= prog->regback; |
175 | if (s < string) |
176 | s = string; |
177 | minlen = prog->regback + prog->regmust->str_cur; |
178 | } |
179 | else if (--prog->regmust->str_u.str_useful < 0) { /* boo */ |
180 | str_free(prog->regmust); |
181 | prog->regmust = Nullstr; /* disable regmust */ |
182 | s = string; |
183 | } |
184 | else { |
185 | s = string; |
186 | minlen = prog->regmust->str_cur; |
187 | } |
188 | } |
189 | |
190 | /* Mark beginning of line for ^ . */ |
ac58e20f |
191 | regbol = string; |
a687059c |
192 | |
193 | /* Mark end of line for $ (and such) */ |
194 | regeol = strend; |
195 | |
196 | /* see how far we have to get to not match where we matched before */ |
197 | regtill = string+minend; |
198 | |
199 | /* Simplest case: anchored match need be tried only once. */ |
200 | /* [unless multiline is set] */ |
201 | if (prog->reganch) { |
202 | if (regtry(prog, string)) |
203 | goto got_it; |
204 | else if (multiline) { |
205 | if (minlen) |
206 | dontbother = minlen - 1; |
207 | strend -= dontbother; |
208 | /* for multiline we only have to try after newlines */ |
209 | if (s > string) |
210 | s--; |
211 | for (; s < strend; s++) { |
212 | if (*s == '\n') { |
213 | if (++s < strend && regtry(prog, s)) |
214 | goto got_it; |
215 | } |
216 | } |
217 | } |
218 | goto phooey; |
219 | } |
220 | |
221 | /* Messy cases: unanchored match. */ |
222 | if (prog->regstart) { |
223 | /* We know what string it must start with. */ |
224 | if (prog->regstart->str_pok == 3) { |
225 | #ifndef lint |
226 | while ((s = fbminstr((unsigned char*)s, |
227 | (unsigned char*)strend, prog->regstart)) != NULL) |
228 | #else |
229 | while (s = Nullch) |
230 | #endif |
231 | { |
232 | if (regtry(prog, s)) |
233 | goto got_it; |
234 | s++; |
235 | } |
236 | } |
237 | else { |
238 | c = prog->regstart->str_ptr; |
239 | while ((s = ninstr(s, strend, |
240 | c, c + prog->regstart->str_cur )) != NULL) { |
241 | if (regtry(prog, s)) |
242 | goto got_it; |
243 | s++; |
244 | } |
245 | } |
246 | goto phooey; |
247 | } |
248 | if (c = prog->regstclass) { |
249 | if (minlen) |
250 | dontbother = minlen - 1; |
251 | strend -= dontbother; /* don't bother with what can't match */ |
252 | /* We know what class it must start with. */ |
253 | switch (OP(c)) { |
254 | case ANYOF: case ANYBUT: |
255 | c = OPERAND(c); |
256 | while (s < strend) { |
ac58e20f |
257 | i = UCHARAT(s); |
a687059c |
258 | if (!(c[i >> 3] & (1 << (i&7)))) |
259 | if (regtry(prog, s)) |
260 | goto got_it; |
261 | s++; |
262 | } |
263 | break; |
264 | case BOUND: |
265 | if (minlen) |
266 | dontbother++,strend--; |
267 | if (s != string) { |
268 | i = s[-1]; |
ac58e20f |
269 | tmp = isALNUM(i); |
a687059c |
270 | } |
271 | else |
ac58e20f |
272 | tmp = isALNUM(regprev); /* assume not alphanumeric */ |
a687059c |
273 | while (s < strend) { |
274 | i = *s; |
ac58e20f |
275 | if (tmp != isALNUM(i)) { |
a687059c |
276 | tmp = !tmp; |
277 | if (regtry(prog, s)) |
278 | goto got_it; |
279 | } |
280 | s++; |
281 | } |
ae986130 |
282 | if ((minlen || tmp) && regtry(prog,s)) |
a687059c |
283 | goto got_it; |
284 | break; |
285 | case NBOUND: |
286 | if (minlen) |
287 | dontbother++,strend--; |
288 | if (s != string) { |
289 | i = s[-1]; |
ac58e20f |
290 | tmp = isALNUM(i); |
a687059c |
291 | } |
292 | else |
ac58e20f |
293 | tmp = isALNUM(regprev); /* assume not alphanumeric */ |
a687059c |
294 | while (s < strend) { |
295 | i = *s; |
ac58e20f |
296 | if (tmp != isALNUM(i)) |
a687059c |
297 | tmp = !tmp; |
298 | else if (regtry(prog, s)) |
299 | goto got_it; |
300 | s++; |
301 | } |
ae986130 |
302 | if ((minlen || !tmp) && regtry(prog,s)) |
a687059c |
303 | goto got_it; |
304 | break; |
305 | case ALNUM: |
306 | while (s < strend) { |
307 | i = *s; |
ac58e20f |
308 | if (isALNUM(i)) |
a687059c |
309 | if (regtry(prog, s)) |
310 | goto got_it; |
311 | s++; |
312 | } |
313 | break; |
314 | case NALNUM: |
315 | while (s < strend) { |
316 | i = *s; |
ac58e20f |
317 | if (!isALNUM(i)) |
a687059c |
318 | if (regtry(prog, s)) |
319 | goto got_it; |
320 | s++; |
321 | } |
322 | break; |
323 | case SPACE: |
324 | while (s < strend) { |
ac58e20f |
325 | if (isSPACE(*s)) |
a687059c |
326 | if (regtry(prog, s)) |
327 | goto got_it; |
328 | s++; |
329 | } |
330 | break; |
331 | case NSPACE: |
332 | while (s < strend) { |
ac58e20f |
333 | if (!isSPACE(*s)) |
a687059c |
334 | if (regtry(prog, s)) |
335 | goto got_it; |
336 | s++; |
337 | } |
338 | break; |
339 | case DIGIT: |
340 | while (s < strend) { |
ac58e20f |
341 | if (isDIGIT(*s)) |
a687059c |
342 | if (regtry(prog, s)) |
343 | goto got_it; |
344 | s++; |
345 | } |
346 | break; |
347 | case NDIGIT: |
348 | while (s < strend) { |
ac58e20f |
349 | if (!isDIGIT(*s)) |
a687059c |
350 | if (regtry(prog, s)) |
351 | goto got_it; |
352 | s++; |
353 | } |
354 | break; |
355 | } |
356 | } |
357 | else { |
663a0e37 |
358 | if (minlen) |
359 | dontbother = minlen - 1; |
a687059c |
360 | strend -= dontbother; |
361 | /* We don't know much -- general case. */ |
362 | do { |
363 | if (regtry(prog, s)) |
364 | goto got_it; |
365 | } while (s++ < strend); |
366 | } |
367 | |
368 | /* Failure. */ |
369 | goto phooey; |
370 | |
371 | got_it: |
372 | if ((!safebase && (prog->nparens || sawampersand)) || prog->do_folding){ |
373 | strend += dontbother; /* uncheat */ |
374 | if (safebase) /* no need for $digit later */ |
375 | s = strbeg; |
376 | else if (strbeg != prog->subbase) { |
377 | i = strend - string + (stringarg - strbeg); |
378 | s = nsavestr(strbeg,i); /* so $digit will work later */ |
379 | if (prog->subbase) |
380 | Safefree(prog->subbase); |
381 | prog->subbase = s; |
382 | } |
383 | else |
384 | s = prog->subbase; |
385 | s += (stringarg - strbeg); |
386 | for (i = 0; i <= prog->nparens; i++) { |
387 | if (prog->endp[i]) { |
388 | prog->startp[i] = s + (prog->startp[i] - string); |
389 | prog->endp[i] = s + (prog->endp[i] - string); |
390 | } |
391 | } |
392 | if (prog->do_folding) |
393 | Safefree(string); |
394 | } |
395 | return(1); |
396 | |
397 | phooey: |
398 | if (prog->do_folding) |
399 | Safefree(string); |
400 | return(0); |
401 | } |
402 | |
403 | /* |
404 | - regtry - try match at specific point |
405 | */ |
406 | static int /* 0 failure, 1 success */ |
407 | regtry(prog, string) |
408 | regexp *prog; |
409 | char *string; |
410 | { |
411 | register int i; |
412 | register char **sp; |
413 | register char **ep; |
414 | |
415 | reginput = string; |
416 | regstartp = prog->startp; |
417 | regendp = prog->endp; |
418 | reglastparen = &prog->lastparen; |
419 | prog->lastparen = 0; |
420 | |
421 | sp = prog->startp; |
422 | ep = prog->endp; |
423 | if (prog->nparens) { |
424 | for (i = NSUBEXP; i > 0; i--) { |
425 | *sp++ = NULL; |
426 | *ep++ = NULL; |
427 | } |
428 | } |
429 | if (regmatch(prog->program + 1) && reginput >= regtill) { |
430 | prog->startp[0] = string; |
431 | prog->endp[0] = reginput; |
432 | return(1); |
433 | } else |
434 | return(0); |
435 | } |
436 | |
437 | /* |
438 | - regmatch - main matching routine |
439 | * |
440 | * Conceptually the strategy is simple: check to see whether the current |
441 | * node matches, call self recursively to see whether the rest matches, |
442 | * and then act accordingly. In practice we make some effort to avoid |
443 | * recursion, in particular by going through "ordinary" nodes (that don't |
444 | * need to know whether the rest of the match failed) by a loop instead of |
445 | * by recursion. |
446 | */ |
447 | /* [lwall] I've hoisted the register declarations to the outer block in order to |
448 | * maybe save a little bit of pushing and popping on the stack. It also takes |
449 | * advantage of machines that use a register save mask on subroutine entry. |
450 | */ |
451 | static int /* 0 failure, 1 success */ |
452 | regmatch(prog) |
453 | char *prog; |
454 | { |
455 | register char *scan; /* Current node. */ |
456 | char *next; /* Next node. */ |
457 | register int nextchar; |
458 | register int n; /* no or next */ |
459 | register int ln; /* len or last */ |
460 | register char *s; /* operand or save */ |
461 | register char *locinput = reginput; |
462 | |
463 | nextchar = *locinput; |
464 | scan = prog; |
465 | #ifdef DEBUGGING |
466 | if (scan != NULL && regnarrate) |
467 | fprintf(stderr, "%s(\n", regprop(scan)); |
468 | #endif |
469 | while (scan != NULL) { |
470 | #ifdef DEBUGGING |
471 | if (regnarrate) |
472 | fprintf(stderr, "%s...\n", regprop(scan)); |
473 | #endif |
474 | |
475 | #ifdef REGALIGN |
476 | next = scan + NEXT(scan); |
477 | if (next == scan) |
478 | next = NULL; |
479 | #else |
480 | next = regnext(scan); |
481 | #endif |
482 | |
483 | switch (OP(scan)) { |
484 | case BOL: |
ac58e20f |
485 | if (locinput == regbol ? regprev == '\n' : |
a687059c |
486 | ((nextchar || locinput < regeol) && |
487 | locinput[-1] == '\n') ) |
488 | { |
489 | regtill--; |
490 | break; |
491 | } |
492 | return(0); |
493 | case EOL: |
494 | if ((nextchar || locinput < regeol) && nextchar != '\n') |
495 | return(0); |
496 | regtill--; |
497 | break; |
498 | case ANY: |
499 | if ((nextchar == '\0' && locinput >= regeol) || |
500 | nextchar == '\n') |
501 | return(0); |
502 | nextchar = *++locinput; |
503 | break; |
504 | case EXACTLY: |
505 | s = OPERAND(scan); |
506 | ln = *s++; |
507 | /* Inline the first character, for speed. */ |
508 | if (*s != nextchar) |
509 | return(0); |
510 | if (locinput + ln > regeol) |
511 | return 0; |
512 | if (ln > 1 && bcmp(s, locinput, ln) != 0) |
513 | return(0); |
514 | locinput += ln; |
515 | nextchar = *locinput; |
516 | break; |
517 | case ANYOF: |
518 | case ANYBUT: |
519 | s = OPERAND(scan); |
520 | if (nextchar < 0) |
521 | nextchar = UCHARAT(locinput); |
522 | if (s[nextchar >> 3] & (1 << (nextchar&7))) |
523 | return(0); |
524 | nextchar = *++locinput; |
525 | if (!nextchar && locinput > regeol) |
526 | return 0; |
527 | break; |
528 | case ALNUM: |
529 | if (!nextchar) |
530 | return(0); |
ac58e20f |
531 | if (!isALNUM(nextchar)) |
a687059c |
532 | return(0); |
533 | nextchar = *++locinput; |
534 | break; |
535 | case NALNUM: |
536 | if (!nextchar && locinput >= regeol) |
537 | return(0); |
ac58e20f |
538 | if (isALNUM(nextchar)) |
a687059c |
539 | return(0); |
540 | nextchar = *++locinput; |
541 | break; |
542 | case NBOUND: |
543 | case BOUND: |
544 | if (locinput == regbol) /* was last char in word? */ |
ac58e20f |
545 | ln = isALNUM(regprev); |
a687059c |
546 | else |
ac58e20f |
547 | ln = isALNUM(locinput[-1]); |
548 | n = isALNUM(nextchar); /* is next char in word? */ |
a687059c |
549 | if ((ln == n) == (OP(scan) == BOUND)) |
550 | return(0); |
551 | break; |
552 | case SPACE: |
553 | if (!nextchar && locinput >= regeol) |
554 | return(0); |
ac58e20f |
555 | if (!isSPACE(nextchar)) |
a687059c |
556 | return(0); |
557 | nextchar = *++locinput; |
558 | break; |
559 | case NSPACE: |
560 | if (!nextchar) |
561 | return(0); |
ac58e20f |
562 | if (isSPACE(nextchar)) |
a687059c |
563 | return(0); |
564 | nextchar = *++locinput; |
565 | break; |
566 | case DIGIT: |
ac58e20f |
567 | if (!isDIGIT(nextchar)) |
a687059c |
568 | return(0); |
569 | nextchar = *++locinput; |
570 | break; |
571 | case NDIGIT: |
572 | if (!nextchar && locinput >= regeol) |
573 | return(0); |
ac58e20f |
574 | if (isDIGIT(nextchar)) |
a687059c |
575 | return(0); |
576 | nextchar = *++locinput; |
577 | break; |
578 | case REF: |
579 | case REF+1: |
580 | case REF+2: |
581 | case REF+3: |
582 | case REF+4: |
583 | case REF+5: |
584 | case REF+6: |
585 | case REF+7: |
586 | case REF+8: |
587 | case REF+9: |
588 | n = OP(scan) - REF; |
589 | s = regmystartp[n]; |
590 | if (!s) |
591 | return(0); |
592 | if (!regmyendp[n]) |
593 | return(0); |
594 | if (s == regmyendp[n]) |
595 | break; |
596 | /* Inline the first character, for speed. */ |
597 | if (*s != nextchar) |
598 | return(0); |
599 | ln = regmyendp[n] - s; |
600 | if (locinput + ln > regeol) |
601 | return 0; |
602 | if (ln > 1 && bcmp(s, locinput, ln) != 0) |
603 | return(0); |
604 | locinput += ln; |
605 | nextchar = *locinput; |
606 | break; |
607 | |
608 | case NOTHING: |
609 | break; |
610 | case BACK: |
611 | break; |
612 | case OPEN+1: |
613 | case OPEN+2: |
614 | case OPEN+3: |
615 | case OPEN+4: |
616 | case OPEN+5: |
617 | case OPEN+6: |
618 | case OPEN+7: |
619 | case OPEN+8: |
620 | case OPEN+9: |
621 | n = OP(scan) - OPEN; |
622 | reginput = locinput; |
623 | |
624 | regmystartp[n] = locinput; /* for REF */ |
625 | if (regmatch(next)) { |
626 | /* |
627 | * Don't set startp if some later |
628 | * invocation of the same parentheses |
629 | * already has. |
630 | */ |
631 | if (regstartp[n] == NULL) |
632 | regstartp[n] = locinput; |
633 | return(1); |
634 | } else |
635 | return(0); |
636 | /* NOTREACHED */ |
637 | case CLOSE+1: |
638 | case CLOSE+2: |
639 | case CLOSE+3: |
640 | case CLOSE+4: |
641 | case CLOSE+5: |
642 | case CLOSE+6: |
643 | case CLOSE+7: |
644 | case CLOSE+8: |
645 | case CLOSE+9: { |
646 | n = OP(scan) - CLOSE; |
647 | reginput = locinput; |
648 | |
649 | regmyendp[n] = locinput; /* for REF */ |
650 | if (regmatch(next)) { |
651 | /* |
652 | * Don't set endp if some later |
653 | * invocation of the same parentheses |
654 | * already has. |
655 | */ |
656 | if (regendp[n] == NULL) { |
657 | regendp[n] = locinput; |
658 | if (n > *reglastparen) |
659 | *reglastparen = n; |
660 | } |
661 | return(1); |
662 | } else |
663 | return(0); |
664 | } |
665 | /*NOTREACHED*/ |
666 | case BRANCH: { |
667 | if (OP(next) != BRANCH) /* No choice. */ |
668 | next = NEXTOPER(scan); /* Avoid recursion. */ |
669 | else { |
670 | do { |
671 | reginput = locinput; |
672 | if (regmatch(NEXTOPER(scan))) |
673 | return(1); |
674 | #ifdef REGALIGN |
675 | if (n = NEXT(scan)) |
676 | scan += n; |
677 | else |
678 | scan = NULL; |
679 | #else |
680 | scan = regnext(scan); |
681 | #endif |
682 | } while (scan != NULL && OP(scan) == BRANCH); |
683 | return(0); |
684 | /* NOTREACHED */ |
685 | } |
686 | } |
687 | break; |
688 | case STAR: |
689 | case PLUS: |
690 | /* |
691 | * Lookahead to avoid useless match attempts |
692 | * when we know what character comes next. |
693 | */ |
694 | if (OP(next) == EXACTLY) |
695 | nextchar = *(OPERAND(next)+1); |
696 | else |
697 | nextchar = -1000; |
698 | ln = (OP(scan) == STAR) ? 0 : 1; |
699 | reginput = locinput; |
700 | n = regrepeat(NEXTOPER(scan)); |
701 | while (n >= ln) { |
702 | /* If it could work, try it. */ |
703 | if (nextchar == -1000 || *reginput == nextchar) |
704 | if (regmatch(next)) |
705 | return(1); |
706 | /* Couldn't or didn't -- back up. */ |
707 | n--; |
708 | reginput = locinput + n; |
709 | } |
710 | return(0); |
711 | case END: |
712 | reginput = locinput; /* put where regtry can find it */ |
713 | return(1); /* Success! */ |
714 | default: |
715 | printf("%x %d\n",scan,scan[1]); |
716 | FAIL("regexp memory corruption"); |
717 | } |
718 | |
719 | scan = next; |
720 | } |
721 | |
722 | /* |
723 | * We get here only if there's trouble -- normally "case END" is |
724 | * the terminating point. |
725 | */ |
726 | FAIL("corrupted regexp pointers"); |
727 | /*NOTREACHED*/ |
728 | #ifdef lint |
729 | return 0; |
730 | #endif |
731 | } |
732 | |
733 | /* |
734 | - regrepeat - repeatedly match something simple, report how many |
735 | */ |
736 | /* |
737 | * [This routine now assumes that it will only match on things of length 1. |
738 | * That was true before, but now we assume scan - reginput is the count, |
739 | * rather than incrementing count on every character.] |
740 | */ |
741 | static int |
742 | regrepeat(p) |
743 | char *p; |
744 | { |
745 | register char *scan; |
746 | register char *opnd; |
747 | register int c; |
748 | register char *loceol = regeol; |
749 | |
750 | scan = reginput; |
751 | opnd = OPERAND(p); |
752 | switch (OP(p)) { |
753 | case ANY: |
754 | while (scan < loceol && *scan != '\n') |
755 | scan++; |
756 | break; |
757 | case EXACTLY: /* length of string is 1 */ |
758 | opnd++; |
759 | while (scan < loceol && *opnd == *scan) |
760 | scan++; |
761 | break; |
762 | case ANYOF: |
763 | case ANYBUT: |
764 | c = UCHARAT(scan); |
765 | while (scan < loceol && !(opnd[c >> 3] & (1 << (c & 7)))) { |
766 | scan++; |
767 | c = UCHARAT(scan); |
768 | } |
769 | break; |
770 | case ALNUM: |
ac58e20f |
771 | while (isALNUM(*scan)) |
a687059c |
772 | scan++; |
773 | break; |
774 | case NALNUM: |
ac58e20f |
775 | while (scan < loceol && !isALNUM(*scan)) |
a687059c |
776 | scan++; |
777 | break; |
778 | case SPACE: |
ac58e20f |
779 | while (scan < loceol && isSPACE(*scan)) |
a687059c |
780 | scan++; |
781 | break; |
782 | case NSPACE: |
ac58e20f |
783 | while (scan < loceol && !isSPACE(*scan)) |
a687059c |
784 | scan++; |
785 | break; |
786 | case DIGIT: |
ac58e20f |
787 | while (isDIGIT(*scan)) |
a687059c |
788 | scan++; |
789 | break; |
790 | case NDIGIT: |
ac58e20f |
791 | while (scan < loceol && !isDIGIT(*scan)) |
a687059c |
792 | scan++; |
793 | break; |
794 | default: /* Oh dear. Called inappropriately. */ |
795 | FAIL("internal regexp foulup"); |
796 | /* NOTREACHED */ |
797 | } |
798 | |
799 | c = scan - reginput; |
800 | reginput = scan; |
801 | |
802 | return(c); |
803 | } |
804 | |
805 | /* |
806 | - regnext - dig the "next" pointer out of a node |
807 | * |
808 | * [Note, when REGALIGN is defined there are two places in regmatch() |
809 | * that bypass this code for speed.] |
810 | */ |
811 | char * |
812 | regnext(p) |
813 | register char *p; |
814 | { |
815 | register int offset; |
816 | |
817 | if (p == ®dummy) |
818 | return(NULL); |
819 | |
820 | offset = NEXT(p); |
821 | if (offset == 0) |
822 | return(NULL); |
823 | |
824 | #ifdef REGALIGN |
825 | return(p+offset); |
826 | #else |
827 | if (OP(p) == BACK) |
828 | return(p-offset); |
829 | else |
830 | return(p+offset); |
831 | #endif |
832 | } |