5 * "One Ring to rule them all, One Ring to find them..."
8 /* NOTE: this is derived from Henry Spencer's regexp code, and should not
9 * confused with the original package (see point 3 below). Thanks, Henry!
12 /* Additional note: this code is very heavily munged from Henry's version
13 * in places. In some spots I've traded clarity for efficiency, so don't
14 * blame Henry for some of the lack of readability.
17 /* The names of the functions have been changed from regcomp and
18 * regexec to pregcomp and pregexec in order to avoid conflicts
19 * with the POSIX routines of the same names.
24 * pregcomp and pregexec -- regsub and regerror are not used in perl
26 * Copyright (c) 1986 by University of Toronto.
27 * Written by Henry Spencer. Not derived from licensed software.
29 * Permission is granted to anyone to use this software for any
30 * purpose on any computer system, and to redistribute it freely,
31 * subject to the following restrictions:
33 * 1. The author is not responsible for the consequences of use of
34 * this software, no matter how awful, even if they arise
37 * 2. The origin of this software must not be misrepresented, either
38 * by explicit claim or by omission.
40 * 3. Altered versions must be plainly marked as such, and must not
41 * be misrepresented as being the original software.
43 **** Alterations to Henry's code are...
45 **** Copyright (c) 1991-1997, Larry Wall
47 **** You may distribute under the terms of either the GNU General Public
48 **** License or the Artistic License, as specified in the README file.
50 * Beware that some of this code is subtly aware of the way operator
51 * precedence is structured in regular expressions. Serious changes in
52 * regular-expression syntax might require a total rethink.
63 static I32 regnarrate = 0;
64 static char* regprogram = 0;
67 /* Current curly descriptor */
68 typedef struct curcur CURCUR;
70 int parenfloor; /* how far back to strip paren data */
71 int cur; /* how many instances of scan we've matched */
72 int min; /* the minimal number of scans to match */
73 int max; /* the maximal number of scans to match */
74 int minmod; /* whether to work our way up or down */
75 char * scan; /* the thing to match */
76 char * next; /* what has to match after it */
77 char * lastloc; /* where we started matching this scan */
78 CURCUR * oldcc; /* current curly before we started this one */
83 typedef I32 CHECKPOINT;
85 static CHECKPOINT regcppush _((I32 parenfloor));
86 static char * regcppop _((void));
92 int retval = savestack_ix;
93 int i = (regsize - parenfloor) * 3;
97 for (p = regsize; p > parenfloor; p--) {
98 SSPUSHPTR(regendp[p]);
99 SSPUSHPTR(regstartp[p]);
103 SSPUSHINT(*reglastparen);
106 SSPUSHINT(SAVEt_REGCONTEXT);
117 assert(i == SAVEt_REGCONTEXT);
119 input = (char *) SSPOPPTR;
120 *reglastparen = SSPOPINT;
122 for (i -= 3; i > 0; i -= 3) {
123 paren = (U32)SSPOPINT;
124 regstartp[paren] = (char *) SSPOPPTR;
125 tmps = (char*)SSPOPPTR;
126 if (paren <= *reglastparen)
127 regendp[paren] = tmps;
129 for (paren = *reglastparen + 1; paren <= regnpar; paren++) {
131 regstartp[paren] = Nullch;
132 regendp[paren] = Nullch;
147 assert(i == SAVEt_REGCONTEXT);
149 input = (char *) SSPOPPTR;
150 lastparen = SSPOPINT;
152 for (i -= 3; i > 0; i -= 3) {
153 paren = (U32)SSPOPINT;
154 startp = (char *) SSPOPPTR;
155 endp = (char *) SSPOPPTR;
156 if (paren <= *reglastparen && regendp[paren] == endp)
157 regstartp[paren] = startp;
161 #define regcpblow(cp) leave_scope(cp)
164 * pregexec and friends
171 static I32 regmatch _((char *prog));
172 static I32 regrepeat _((char *p, I32 max));
173 static I32 regtry _((regexp *prog, char *startpos));
174 static bool reginclass _((char *p, I32 c));
176 static bool regtainted; /* tainted information used? */
179 - pregexec - match a regexp against a string
182 pregexec(prog, stringarg, strend, strbeg, minend, screamer, safebase)
183 register regexp *prog;
185 register char *strend; /* pointer to null at end of string */
186 char *strbeg; /* real beginning of string */
187 I32 minend; /* end of match must be at least minend after stringarg */
189 I32 safebase; /* no need to remember string in subbase */
193 register char *startpos = stringarg;
195 I32 minlen = 0; /* must match at least this many chars */
196 I32 dontbother = 0; /* how many characters not to try at end */
204 regnarrate = debug & 512;
205 regprogram = prog->program;
209 if (prog == NULL || startpos == NULL) {
210 croak("NULL regexp parameter");
214 if (startpos == strbeg) /* is ^ valid at stringarg? */
217 regprev = stringarg[-1];
218 if (!multiline && regprev == '\n')
219 regprev = '\0'; /* force ^ to NOT match */
222 regprecomp = prog->precomp;
223 /* Check validity of program. */
224 if (UCHARAT(prog->program) != MAGIC) {
225 FAIL("corrupted regexp program");
228 regnpar = prog->nparens;
231 /* If there is a "must appear" string, look for it. */
233 if (prog->regmust != Nullsv &&
234 !(prog->reganch & ROPT_ANCH_GPOS) &&
235 (!(prog->reganch & ROPT_ANCH_BOL)
236 || (multiline && prog->regback >= 0)) )
238 if (stringarg == strbeg && screamer) {
239 if (screamfirst[BmRARE(prog->regmust)] >= 0)
240 s = screaminstr(screamer,prog->regmust);
245 s = fbm_instr((unsigned char*)s, (unsigned char*)strend,
248 ++BmUSEFUL(prog->regmust); /* hooray */
249 goto phooey; /* not present */
251 else if (prog->regback >= 0) {
255 minlen = prog->regback + SvCUR(prog->regmust);
257 else if (!prog->naughty && --BmUSEFUL(prog->regmust) < 0) { /* boo */
258 SvREFCNT_dec(prog->regmust);
259 prog->regmust = Nullsv; /* disable regmust */
264 minlen = SvCUR(prog->regmust);
268 /* Mark beginning of line for ^ . */
271 /* Mark end of line for $ (and such) */
274 /* see how far we have to get to not match where we matched before */
275 regtill = startpos+minend;
277 /* Simplest case: anchored match need be tried only once. */
278 /* [unless only anchor is BOL and multiline is set] */
279 if (prog->reganch & ROPT_ANCH) {
280 if (regtry(prog, startpos))
282 else if (!(prog->reganch & ROPT_ANCH_GPOS) &&
283 (multiline || (prog->reganch & ROPT_IMPLICIT)))
286 dontbother = minlen - 1;
287 strend -= dontbother;
288 /* for multiline we only have to try after newlines */
293 if (s < strend && regtry(prog, s))
301 /* Messy cases: unanchored match. */
302 if (prog->regstart) {
303 if (prog->reganch & ROPT_SKIP) { /* we have /x+whatever/ */
304 /* it must be a one character string */
305 char ch = SvPVX(prog->regstart)[0];
311 while (s < strend && *s == ch)
317 else if (SvTYPE(prog->regstart) == SVt_PVBM) {
318 /* We know what string it must start with. */
319 while ((s = fbm_instr((unsigned char*)s,
320 (unsigned char*)strend, prog->regstart)) != NULL)
327 else { /* Optimized fbm_instr: */
328 c = SvPVX(prog->regstart);
329 while ((s = ninstr(s, strend, c, c + SvCUR(prog->regstart))) != NULL)
339 if (c = prog->regstclass) {
340 I32 doevery = (prog->reganch & ROPT_SKIP) == 0;
343 dontbother = minlen - 1;
344 strend -= dontbother; /* don't bother with what can't match */
346 /* We know what class it must start with. */
351 if (reginclass(c, *s)) {
352 if (tmp && regtry(prog, s))
367 dontbother++,strend--;
368 tmp = (s != startpos) ? UCHARAT(s - 1) : regprev;
369 tmp = ((OP(c) == BOUND ? isALNUM(tmp) : isALNUM_LC(tmp)) != 0);
371 if (tmp == !(OP(c) == BOUND ? isALNUM(*s) : isALNUM_LC(*s))) {
378 if ((minlen || tmp) && regtry(prog,s))
386 dontbother++,strend--;
387 tmp = (s != startpos) ? UCHARAT(s - 1) : regprev;
388 tmp = ((OP(c) == NBOUND ? isALNUM(tmp) : isALNUM_LC(tmp)) != 0);
390 if (tmp == !(OP(c) == NBOUND ? isALNUM(*s) : isALNUM_LC(*s)))
392 else if (regtry(prog, s))
396 if ((minlen || !tmp) && regtry(prog,s))
402 if (tmp && regtry(prog, s))
415 if (isALNUM_LC(*s)) {
416 if (tmp && regtry(prog, s))
429 if (tmp && regtry(prog, s))
442 if (!isALNUM_LC(*s)) {
443 if (tmp && regtry(prog, s))
456 if (tmp && regtry(prog, s))
469 if (isSPACE_LC(*s)) {
470 if (tmp && regtry(prog, s))
483 if (tmp && regtry(prog, s))
496 if (!isSPACE_LC(*s)) {
497 if (tmp && regtry(prog, s))
510 if (tmp && regtry(prog, s))
523 if (tmp && regtry(prog, s))
537 dontbother = minlen - 1;
538 strend -= dontbother;
539 /* We don't know much -- general case. */
543 } while (s++ < strend);
550 strend += dontbother; /* uncheat */
551 prog->subbeg = strbeg;
552 prog->subend = strend;
553 prog->exec_tainted = regtainted;
555 /* make sure $`, $&, $', and $digit will work later */
556 if (strbeg != prog->subbase) {
559 Safefree(prog->subbase);
560 prog->subbase = Nullch;
564 I32 i = strend - startpos + (stringarg - strbeg);
565 s = savepvn(strbeg, i);
566 Safefree(prog->subbase);
568 prog->subbeg = prog->subbase;
569 prog->subend = prog->subbase + i;
570 s = prog->subbase + (stringarg - strbeg);
571 for (i = 0; i <= prog->nparens; i++) {
573 prog->startp[i] = s + (prog->startp[i] - startpos);
574 prog->endp[i] = s + (prog->endp[i] - startpos);
586 - regtry - try match at specific point
588 static I32 /* 0 failure, 1 success */
589 regtry(prog, startpos)
598 regstartp = prog->startp;
599 regendp = prog->endp;
600 reglastparen = &prog->lastparen;
607 for (i = prog->nparens; i >= 0; i--) {
612 if (regmatch(prog->program + 1) && reginput >= regtill) {
613 prog->startp[0] = startpos;
614 prog->endp[0] = reginput;
622 - regmatch - main matching routine
624 * Conceptually the strategy is simple: check to see whether the current
625 * node matches, call self recursively to see whether the rest matches,
626 * and then act accordingly. In practice we make some effort to avoid
627 * recursion, in particular by going through "ordinary" nodes (that don't
628 * need to know whether the rest of the match failed) by a loop instead of
631 /* [lwall] I've hoisted the register declarations to the outer block in order to
632 * maybe save a little bit of pushing and popping on the stack. It also takes
633 * advantage of machines that use a register save mask on subroutine entry.
635 static I32 /* 0 failure, 1 success */
639 register char *scan; /* Current node. */
640 char *next; /* Next node. */
641 register I32 nextchar;
642 register I32 n; /* no or next */
643 register I32 ln; /* len or last */
644 register char *s; /* operand or save */
645 register char *locinput = reginput;
646 register I32 c1, c2; /* case fold search */
649 static int regindent = 0;
653 nextchar = UCHARAT(locinput);
655 while (scan != NULL) {
657 #define sayYES goto yes
658 #define sayNO goto no
659 #define saySAME(x) if (x) goto yes; else goto no
661 SV *prop = sv_newmortal();
663 PerlIO_printf(Perl_debug_log, "%*s%2d%-8.8s\t<%.10s>\n",
664 regindent*2, "", scan - regprogram,
665 SvPVX(prop), locinput);
668 #define sayYES return 1
669 #define sayNO return 0
670 #define saySAME(x) return x
674 next = scan + NEXT(scan);
678 next = regnext(scan);
683 if (locinput == regbol
685 : ((nextchar || locinput < regeol) && locinput[-1] == '\n') )
687 /* regtill = regbol; */
692 if (locinput == regbol
694 : ((nextchar || locinput < regeol) && locinput[-1] == '\n') )
700 if (locinput == regbol && regprev == '\n')
704 if (locinput == regbol)
714 if ((nextchar || locinput < regeol) && nextchar != '\n')
719 if ((nextchar || locinput < regeol) && nextchar != '\n')
721 if (regeol - locinput > 1)
725 if (!nextchar && locinput >= regeol)
727 nextchar = UCHARAT(++locinput);
730 if (!nextchar && locinput >= regeol || nextchar == '\n')
732 nextchar = UCHARAT(++locinput);
737 /* Inline the first character, for speed. */
738 if (UCHARAT(s) != nextchar)
740 if (regeol - locinput < ln)
742 if (ln > 1 && memNE(s, locinput, ln))
745 nextchar = UCHARAT(locinput);
753 /* Inline the first character, for speed. */
754 if (UCHARAT(s) != nextchar &&
755 UCHARAT(s) != ((OP(scan) == EXACTF)
756 ? fold : fold_locale)[nextchar])
758 if (regeol - locinput < ln)
760 if (ln > 1 && (OP(scan) == EXACTF
761 ? ibcmp(s, locinput, ln)
762 : ibcmp_locale(s, locinput, ln)))
765 nextchar = UCHARAT(locinput);
770 nextchar = UCHARAT(locinput);
771 if (!reginclass(s, nextchar))
773 if (!nextchar && locinput >= regeol)
775 nextchar = UCHARAT(++locinput);
783 if (!(OP(scan) == ALNUM
784 ? isALNUM(nextchar) : isALNUM_LC(nextchar)))
786 nextchar = UCHARAT(++locinput);
792 if (!nextchar && locinput >= regeol)
794 if (OP(scan) == NALNUM
795 ? isALNUM(nextchar) : isALNUM_LC(nextchar))
797 nextchar = UCHARAT(++locinput);
805 /* was last char in word? */
806 ln = (locinput != regbol) ? UCHARAT(locinput - 1) : regprev;
807 if (OP(scan) == BOUND || OP(scan) == NBOUND) {
809 n = isALNUM(nextchar);
813 n = isALNUM_LC(nextchar);
815 if (((!ln) == (!n)) == (OP(scan) == BOUND || OP(scan) == BOUNDL))
822 if (!nextchar && locinput >= regeol)
824 if (!(OP(scan) == SPACE
825 ? isSPACE(nextchar) : isSPACE_LC(nextchar)))
827 nextchar = UCHARAT(++locinput);
835 if (OP(scan) == SPACE
836 ? isSPACE(nextchar) : isSPACE_LC(nextchar))
838 nextchar = UCHARAT(++locinput);
841 if (!isDIGIT(nextchar))
843 nextchar = UCHARAT(++locinput);
846 if (!nextchar && locinput >= regeol)
848 if (isDIGIT(nextchar))
850 nextchar = UCHARAT(++locinput);
857 n = ARG1(scan); /* which paren pair */
865 /* Inline the first character, for speed. */
866 if (UCHARAT(s) != nextchar &&
868 (UCHARAT(s) != ((OP(scan) == REFF
869 ? fold : fold_locale)[nextchar]))))
872 if (locinput + ln > regeol)
874 if (ln > 1 && (OP(scan) == REF
875 ? memNE(s, locinput, ln)
877 ? ibcmp(s, locinput, ln)
878 : ibcmp_locale(s, locinput, ln))))
881 nextchar = UCHARAT(locinput);
889 n = ARG1(scan); /* which paren pair */
890 regstartp[n] = locinput;
896 n = ARG1(scan); /* which paren pair */
897 regendp[n] = locinput;
898 if (n > *reglastparen)
903 CHECKPOINT cp = savestack_ix;
906 cc.parenfloor = *reglastparen;
910 cc.scan = NEXTOPER(scan) + 4;
915 n = regmatch(PREVOPER(next)); /* start on the WHILEM */
923 * This is really hard to understand, because after we match
924 * what we're trying to match, we must make sure the rest of
925 * the RE is going to match for sure, and to do that we have
926 * to go back UP the parse tree by recursing ever deeper. And
927 * if it fails, we have to reset our parent's current state
928 * that we can try again after backing off.
933 n = cc->cur + 1; /* how many we know we matched */
938 PerlIO_printf(Perl_debug_log, "%*s %ld %lx\n", regindent*2, "",
942 /* If degenerate scan matches "", assume scan done. */
944 if (locinput == cc->lastloc && n >= cc->min) {
947 if (regmatch(cc->next))
954 /* First just match a string of min scans. */
958 cc->lastloc = locinput;
959 if (regmatch(cc->scan))
965 /* Prefer next over scan for minimal matching. */
970 cp = regcppush(cc->parenfloor);
971 if (regmatch(cc->next)) {
973 sayYES; /* All done. */
979 if (n >= cc->max) /* Maximum greed exceeded? */
982 /* Try scanning more and see if it helps. */
985 cc->lastloc = locinput;
986 cp = regcppush(cc->parenfloor);
987 if (regmatch(cc->scan)) {
996 /* Prefer scan over next for maximal matching. */
998 if (n < cc->max) { /* More greed allowed? */
999 cp = regcppush(cc->parenfloor);
1001 cc->lastloc = locinput;
1002 if (regmatch(cc->scan)) {
1006 regcppop(); /* Restore some previous $<digit>s? */
1007 reginput = locinput;
1010 /* Failed deeper matches of scan, so see if this one works. */
1013 if (regmatch(cc->next))
1022 if (OP(next) != BRANCH) /* No choice. */
1023 next = NEXTOPER(scan);/* Avoid recursion. */
1025 int lastparen = *reglastparen;
1027 reginput = locinput;
1028 if (regmatch(NEXTOPER(scan)))
1030 for (n = *reglastparen; n > lastparen; n--)
1041 scan = regnext(scan);
1043 } while (scan != NULL && OP(scan) == BRANCH);
1053 ln = ARG1(scan); /* min to match */
1054 n = ARG2(scan); /* max to match */
1055 scan = NEXTOPER(scan) + 4;
1060 scan = NEXTOPER(scan);
1064 * Lookahead to avoid useless match attempts
1065 * when we know what character comes next.
1069 scan = NEXTOPER(scan);
1071 if (regkind[(U8)OP(next)] == EXACT) {
1072 c1 = UCHARAT(OPERAND(next) + 1);
1073 if (OP(next) == EXACTF)
1075 else if (OP(next) == EXACTFL)
1076 c2 = fold_locale[c1];
1082 reginput = locinput;
1085 if (ln && regrepeat(scan, ln) < ln)
1087 while (n >= ln || (n == 32767 && ln > 0)) { /* ln overflow ? */
1088 /* If it could work, try it. */
1090 UCHARAT(reginput) == c1 ||
1091 UCHARAT(reginput) == c2)
1096 /* Couldn't or didn't -- back up. */
1097 reginput = locinput + ln;
1098 if (regrepeat(scan, 1)) {
1100 reginput = locinput + ln;
1107 n = regrepeat(scan, n);
1108 if (ln < n && regkind[(U8)OP(next)] == EOL &&
1109 (!multiline || OP(next) == SEOL))
1110 ln = n; /* why back off? */
1112 /* If it could work, try it. */
1114 UCHARAT(reginput) == c1 ||
1115 UCHARAT(reginput) == c2)
1120 /* Couldn't or didn't -- back up. */
1122 reginput = locinput + n;
1128 reginput = locinput; /* put where regtry can find it */
1129 sayYES; /* Success! */
1131 reginput = locinput;
1132 scan = NEXTOPER(scan);
1133 if (!regmatch(scan))
1137 reginput = locinput;
1138 scan = NEXTOPER(scan);
1143 PerlIO_printf(PerlIO_stderr(), "%lx %d\n",
1144 (unsigned long)scan, scan[1]);
1145 FAIL("regexp memory corruption");
1151 * We get here only if there's trouble -- normally "case END" is
1152 * the terminating point.
1154 FAIL("corrupted regexp pointers");
1172 - regrepeat - repeatedly match something simple, report how many
1175 * [This routine now assumes that it will only match on things of length 1.
1176 * That was true before, but now we assume scan - reginput is the count,
1177 * rather than incrementing count on every character.]
1184 register char *scan;
1185 register char *opnd;
1187 register char *loceol = regeol;
1190 if (max != 32767 && max < loceol - scan)
1191 loceol = scan + max;
1195 while (scan < loceol && *scan != '\n')
1201 case EXACT: /* length of string is 1 */
1202 c = UCHARAT(++opnd);
1203 while (scan < loceol && UCHARAT(scan) == c)
1206 case EXACTF: /* length of string is 1 */
1207 c = UCHARAT(++opnd);
1208 while (scan < loceol &&
1209 (UCHARAT(scan) == c || UCHARAT(scan) == fold[c]))
1212 case EXACTFL: /* length of string is 1 */
1214 c = UCHARAT(++opnd);
1215 while (scan < loceol &&
1216 (UCHARAT(scan) == c || UCHARAT(scan) == fold_locale[c]))
1220 while (scan < loceol && reginclass(opnd, *scan))
1224 while (scan < loceol && isALNUM(*scan))
1229 while (scan < loceol && isALNUM_LC(*scan))
1233 while (scan < loceol && !isALNUM(*scan))
1238 while (scan < loceol && !isALNUM_LC(*scan))
1242 while (scan < loceol && isSPACE(*scan))
1247 while (scan < loceol && isSPACE_LC(*scan))
1251 while (scan < loceol && !isSPACE(*scan))
1256 while (scan < loceol && !isSPACE_LC(*scan))
1260 while (scan < loceol && isDIGIT(*scan))
1264 while (scan < loceol && !isDIGIT(*scan))
1267 default: /* Called on something of 0 width. */
1268 break; /* So match right here or not at all. */
1271 c = scan - reginput;
1278 - regclass - determine if a character falls into a character class
1290 if (p[1 + (c >> 3)] & (1 << (c & 7)))
1292 else if (flags & ANYOF_FOLD) {
1294 if (flags & ANYOF_LOCALE) {
1296 cf = fold_locale[c];
1300 if (p[1 + (cf >> 3)] & (1 << (cf & 7)))
1304 if (!match && (flags & ANYOF_ISA)) {
1307 if (((flags & ANYOF_ALNUML) && isALNUM_LC(c)) ||
1308 ((flags & ANYOF_NALNUML) && !isALNUM_LC(c)) ||
1309 ((flags & ANYOF_SPACEL) && isSPACE_LC(c)) ||
1310 ((flags & ANYOF_NSPACEL) && !isSPACE_LC(c)))
1316 return match ^ ((flags & ANYOF_INVERT) != 0);
1320 - regnext - dig the "next" pointer out of a node
1322 * [Note, when REGALIGN is defined there are two places in regmatch()
1323 * that bypass this code for speed.]
1329 register I32 offset;