typedef I32 CHECKPOINT;
-CHECKPOINT regcppush _((I32 parenfloor));
-char * regcppop _((void));
+static CHECKPOINT regcppush _((I32 parenfloor));
+static char * regcppop _((void));
-CHECKPOINT
+static CHECKPOINT
regcppush(parenfloor)
I32 parenfloor;
{
return retval;
}
-char*
+static char *
regcppop()
{
I32 i = SSPOPINT;
static I32 regmatch _((char *prog));
static I32 regrepeat _((char *p, I32 max));
static I32 regtry _((regexp *prog, char *startpos));
+static bool reginclass _((char *p, I32 c));
+
+static bool regtainted; /* tainted information used? */
/*
- pregexec - match a regexp against a string
I32 safebase; /* no need to remember string in subbase */
{
register char *s;
- register I32 i;
register char *c;
register char *startpos = stringarg;
register I32 tmp;
CURCUR cc;
cc.cur = 0;
+ cc.oldcc = 0;
regcc = &cc;
#ifdef DEBUGGING
if (!multiline && regprev == '\n')
regprev = '\0'; /* force ^ to NOT match */
}
+
regprecomp = prog->precomp;
- regnpar = prog->nparens;
/* Check validity of program. */
if (UCHARAT(prog->program) != MAGIC) {
FAIL("corrupted regexp program");
}
- if (prog->do_folding) {
- i = strend - startpos;
- New(1101,c,i+1,char);
- Copy(startpos, c, i+1, char);
- startpos = c;
- strend = startpos + i;
- for (s = startpos; s < strend; s++)
- if (isUPPER(*s))
- *s = toLOWER(*s);
- }
+ regnpar = prog->nparens;
+ regtainted = FALSE;
/* If there is a "must appear" string, look for it. */
s = startpos;
if (prog->regstart) {
if (prog->reganch & ROPT_SKIP) { /* we have /x+whatever/ */
/* it must be a one character string */
- i = SvPVX(prog->regstart)[0];
+ char ch = SvPVX(prog->regstart)[0];
while (s < strend) {
- if (*s == i) {
+ if (*s == ch) {
if (regtry(prog, s))
goto got_it;
s++;
- while (s < strend && *s == i)
+ while (s < strend && *s == ch)
s++;
}
s++;
case ANYOF:
c = OPERAND(c);
while (s < strend) {
- i = UCHARAT(s);
- if (!(c[i >> 3] & (1 << (i&7)))) {
+ if (reginclass(c, *s)) {
if (tmp && regtry(prog, s))
goto got_it;
else
s++;
}
break;
+ case BOUNDL:
+ regtainted = TRUE;
+ /* FALL THROUGH */
case BOUND:
if (minlen)
dontbother++,strend--;
- if (s != startpos) {
- i = s[-1];
- tmp = isALNUM(i);
- }
- else
- tmp = isALNUM(regprev); /* assume not alphanumeric */
+ tmp = (s != startpos) ? UCHARAT(s - 1) : regprev;
+ tmp = ((OP(c) == BOUND ? isALNUM(tmp) : isALNUM_LC(tmp)) != 0);
while (s < strend) {
- i = *s;
- if (tmp != isALNUM(i)) {
+ if (tmp == !(OP(c) == BOUND ? isALNUM(*s) : isALNUM_LC(*s))) {
tmp = !tmp;
if (regtry(prog, s))
goto got_it;
if ((minlen || tmp) && regtry(prog,s))
goto got_it;
break;
+ case NBOUNDL:
+ regtainted = TRUE;
+ /* FALL THROUGH */
case NBOUND:
if (minlen)
dontbother++,strend--;
- if (s != startpos) {
- i = s[-1];
- tmp = isALNUM(i);
- }
- else
- tmp = isALNUM(regprev); /* assume not alphanumeric */
+ tmp = (s != startpos) ? UCHARAT(s - 1) : regprev;
+ tmp = ((OP(c) == NBOUND ? isALNUM(tmp) : isALNUM_LC(tmp)) != 0);
while (s < strend) {
- i = *s;
- if (tmp != isALNUM(i))
+ if (tmp == !(OP(c) == NBOUND ? isALNUM(*s) : isALNUM_LC(*s)))
tmp = !tmp;
else if (regtry(prog, s))
goto got_it;
break;
case ALNUM:
while (s < strend) {
- i = *s;
- if (isALNUM(i)) {
+ if (isALNUM(*s)) {
+ if (tmp && regtry(prog, s))
+ goto got_it;
+ else
+ tmp = doevery;
+ }
+ else
+ tmp = 1;
+ s++;
+ }
+ break;
+ case ALNUML:
+ regtainted = TRUE;
+ while (s < strend) {
+ if (isALNUM_LC(*s)) {
if (tmp && regtry(prog, s))
goto got_it;
else
break;
case NALNUM:
while (s < strend) {
- i = *s;
- if (!isALNUM(i)) {
+ if (!isALNUM(*s)) {
+ if (tmp && regtry(prog, s))
+ goto got_it;
+ else
+ tmp = doevery;
+ }
+ else
+ tmp = 1;
+ s++;
+ }
+ break;
+ case NALNUML:
+ regtainted = TRUE;
+ while (s < strend) {
+ if (!isALNUM_LC(*s)) {
if (tmp && regtry(prog, s))
goto got_it;
else
s++;
}
break;
+ case SPACEL:
+ regtainted = TRUE;
+ while (s < strend) {
+ if (isSPACE_LC(*s)) {
+ if (tmp && regtry(prog, s))
+ goto got_it;
+ else
+ tmp = doevery;
+ }
+ else
+ tmp = 1;
+ s++;
+ }
+ break;
case NSPACE:
while (s < strend) {
if (!isSPACE(*s)) {
s++;
}
break;
+ case NSPACEL:
+ regtainted = TRUE;
+ while (s < strend) {
+ if (!isSPACE_LC(*s)) {
+ if (tmp && regtry(prog, s))
+ goto got_it;
+ else
+ tmp = doevery;
+ }
+ else
+ tmp = 1;
+ s++;
+ }
+ break;
case DIGIT:
while (s < strend) {
if (isDIGIT(*s)) {
strend += dontbother; /* uncheat */
prog->subbeg = strbeg;
prog->subend = strend;
- if ((!safebase && (prog->nparens || sawampersand)) || prog->do_folding) {
- i = strend - startpos + (stringarg - strbeg);
- if (safebase) { /* no need for $digit later */
- s = strbeg;
- prog->subend = s+i;
- }
- else if (strbeg != prog->subbase) {
- s = savepvn(strbeg,i); /* so $digit will work later */
- if (prog->subbase)
- Safefree(prog->subbase);
- prog->subbeg = prog->subbase = s;
- prog->subend = s+i;
- }
- else {
- prog->subbeg = s = prog->subbase;
- prog->subend = s+i;
- }
- s += (stringarg - strbeg);
+ prog->exec_tainted = regtainted;
+
+ /* make sure $`, $&, $', and $digit will work later */
+ if (!safebase && (strbeg != prog->subbase)) {
+ I32 i = strend - startpos + (stringarg - strbeg);
+ s = savepvn(strbeg, i);
+ Safefree(prog->subbase);
+ prog->subbase = s;
+ prog->subbeg = prog->subbase;
+ prog->subend = prog->subbase + i;
+ s = prog->subbase + (stringarg - strbeg);
for (i = 0; i <= prog->nparens; i++) {
if (prog->endp[i]) {
prog->startp[i] = s + (prog->startp[i] - startpos);
prog->endp[i] = s + (prog->endp[i] - startpos);
}
}
- if (prog->do_folding)
- Safefree(startpos);
}
return 1;
phooey:
- if (prog->do_folding)
- Safefree(startpos);
return 0;
}
register I32 ln; /* len or last */
register char *s; /* operand or save */
register char *locinput = reginput;
+ register I32 c1, c2; /* case fold search */
int minmod = 0;
+#ifdef DEBUGGING
+ static int regindent = 0;
+ regindent++;
+#endif
- nextchar = *locinput;
+ nextchar = UCHARAT(locinput);
scan = prog;
while (scan != NULL) {
#ifdef DEBUGGING
- if (regnarrate)
- fprintf(stderr, "%2d%-8.8s\t<%.10s>\n",
+#define sayYES goto yes
+#define sayNO goto no
+#define saySAME(x) if (x) goto yes; else goto no
+ if (regnarrate) {
+ PerlIO_printf(Perl_debug_log, "%*s%2d%-8.8s\t<%.10s>\n", regindent*2, "",
scan - regprogram, regprop(scan), locinput);
+ }
+#else
+#define sayYES return 1
+#define sayNO return 0
+#define saySAME(x) return x
#endif
#ifdef REGALIGN
/* regtill = regbol; */
break;
}
- return 0;
+ sayNO;
case MBOL:
if (locinput == regbol
? regprev == '\n'
{
break;
}
- return 0;
+ sayNO;
case SBOL:
if (locinput == regbol && regprev == '\n')
break;
- return 0;
+ sayNO;
case GBOL:
if (locinput == regbol)
break;
- return 0;
+ sayNO;
case EOL:
if (multiline)
goto meol;
case MEOL:
meol:
if ((nextchar || locinput < regeol) && nextchar != '\n')
- return 0;
+ sayNO;
break;
case SEOL:
seol:
if ((nextchar || locinput < regeol) && nextchar != '\n')
- return 0;
+ sayNO;
if (regeol - locinput > 1)
- return 0;
+ sayNO;
break;
case SANY:
if (!nextchar && locinput >= regeol)
- return 0;
- nextchar = *++locinput;
+ sayNO;
+ nextchar = UCHARAT(++locinput);
break;
case ANY:
if (!nextchar && locinput >= regeol || nextchar == '\n')
- return 0;
- nextchar = *++locinput;
+ sayNO;
+ nextchar = UCHARAT(++locinput);
+ break;
+ case EXACT:
+ s = OPERAND(scan);
+ ln = *s++;
+ /* Inline the first character, for speed. */
+ if (UCHARAT(s) != nextchar)
+ sayNO;
+ if (regeol - locinput < ln)
+ sayNO;
+ if (ln > 1 && memNE(s, locinput, ln))
+ sayNO;
+ locinput += ln;
+ nextchar = UCHARAT(locinput);
break;
- case EXACTLY:
+ case EXACTFL:
+ regtainted = TRUE;
+ /* FALL THROUGH */
+ case EXACTF:
s = OPERAND(scan);
ln = *s++;
/* Inline the first character, for speed. */
- if (*s != nextchar)
- return 0;
+ if (UCHARAT(s) != nextchar &&
+ UCHARAT(s) != ((OP(scan) == EXACTF)
+ ? fold : fold_locale)[nextchar])
+ sayNO;
if (regeol - locinput < ln)
- return 0;
- if (ln > 1 && bcmp(s, locinput, ln) != 0)
- return 0;
+ sayNO;
+ if (ln > 1 && (OP(scan) == EXACTF
+ ? ibcmp(s, locinput, ln)
+ : ibcmp_locale(s, locinput, ln)))
+ sayNO;
locinput += ln;
- nextchar = *locinput;
+ nextchar = UCHARAT(locinput);
break;
case ANYOF:
s = OPERAND(scan);
if (nextchar < 0)
nextchar = UCHARAT(locinput);
- if (s[nextchar >> 3] & (1 << (nextchar&7)))
- return 0;
+ if (!reginclass(s, nextchar))
+ sayNO;
if (!nextchar && locinput >= regeol)
- return 0;
- nextchar = *++locinput;
+ sayNO;
+ nextchar = UCHARAT(++locinput);
break;
+ case ALNUML:
+ regtainted = TRUE;
+ /* FALL THROUGH */
case ALNUM:
if (!nextchar)
- return 0;
- if (!isALNUM(nextchar))
- return 0;
- nextchar = *++locinput;
+ sayNO;
+ if (!(OP(scan) == ALNUM
+ ? isALNUM(nextchar) : isALNUM_LC(nextchar)))
+ sayNO;
+ nextchar = UCHARAT(++locinput);
break;
+ case NALNUML:
+ regtainted = TRUE;
+ /* FALL THROUGH */
case NALNUM:
if (!nextchar && locinput >= regeol)
- return 0;
- if (isALNUM(nextchar))
- return 0;
- nextchar = *++locinput;
+ sayNO;
+ if (OP(scan) == NALNUM
+ ? isALNUM(nextchar) : isALNUM_LC(nextchar))
+ sayNO;
+ nextchar = UCHARAT(++locinput);
break;
- case NBOUND:
+ case BOUNDL:
+ case NBOUNDL:
+ regtainted = TRUE;
+ /* FALL THROUGH */
case BOUND:
- if (locinput == regbol) /* was last char in word? */
- ln = isALNUM(regprev);
- else
- ln = isALNUM(locinput[-1]);
- n = isALNUM(nextchar); /* is next char in word? */
- if ((ln == n) == (OP(scan) == BOUND))
- return 0;
+ case NBOUND:
+ /* was last char in word? */
+ ln = (locinput != regbol) ? UCHARAT(locinput - 1) : regprev;
+ if (OP(scan) == BOUND || OP(scan) == NBOUND) {
+ ln = isALNUM(ln);
+ n = isALNUM(nextchar);
+ }
+ else {
+ ln = isALNUM_LC(ln);
+ n = isALNUM_LC(nextchar);
+ }
+ if (((!ln) == (!n)) == (OP(scan) == BOUND || OP(scan) == BOUNDL))
+ sayNO;
break;
+ case SPACEL:
+ regtainted = TRUE;
+ /* FALL THROUGH */
case SPACE:
if (!nextchar && locinput >= regeol)
- return 0;
- if (!isSPACE(nextchar))
- return 0;
- nextchar = *++locinput;
+ sayNO;
+ if (!(OP(scan) == SPACE
+ ? isSPACE(nextchar) : isSPACE_LC(nextchar)))
+ sayNO;
+ nextchar = UCHARAT(++locinput);
break;
+ case NSPACEL:
+ regtainted = TRUE;
+ /* FALL THROUGH */
case NSPACE:
if (!nextchar)
- return 0;
- if (isSPACE(nextchar))
- return 0;
- nextchar = *++locinput;
+ sayNO;
+ if (OP(scan) == SPACE
+ ? isSPACE(nextchar) : isSPACE_LC(nextchar))
+ sayNO;
+ nextchar = UCHARAT(++locinput);
break;
case DIGIT:
if (!isDIGIT(nextchar))
- return 0;
- nextchar = *++locinput;
+ sayNO;
+ nextchar = UCHARAT(++locinput);
break;
case NDIGIT:
if (!nextchar && locinput >= regeol)
- return 0;
+ sayNO;
if (isDIGIT(nextchar))
- return 0;
- nextchar = *++locinput;
+ sayNO;
+ nextchar = UCHARAT(++locinput);
break;
case REF:
n = ARG1(scan); /* which paren pair */
s = regstartp[n];
if (!s)
- return 0;
+ sayNO;
if (!regendp[n])
- return 0;
+ sayNO;
if (s == regendp[n])
break;
/* Inline the first character, for speed. */
- if (*s != nextchar)
- return 0;
+ if (UCHARAT(s) != nextchar)
+ sayNO;
ln = regendp[n] - s;
if (locinput + ln > regeol)
- return 0;
- if (ln > 1 && bcmp(s, locinput, ln) != 0)
- return 0;
+ sayNO;
+ if (ln > 1 && memNE(s, locinput, ln))
+ sayNO;
locinput += ln;
- nextchar = *locinput;
+ nextchar = UCHARAT(locinput);
break;
case NOTHING:
n = regmatch(PREVOPER(next)); /* start on the WHILEM */
regcpblow(cp);
regcc = cc.oldcc;
- return n;
+ saySAME(n);
}
/* NOT REACHED */
case WHILEM: {
* that we can try again after backing off.
*/
+ CHECKPOINT cp;
CURCUR* cc = regcc;
- n = cc->cur + 1;
+ n = cc->cur + 1; /* how many we know we matched */
reginput = locinput;
+#ifdef DEBUGGING
+ if (regnarrate)
+ PerlIO_printf(Perl_debug_log, "%*s %d %lx\n", regindent*2, "",
+ n, (long)cc);
+#endif
+
/* If degenerate scan matches "", assume scan done. */
if (locinput == cc->lastloc) {
regcc = cc->oldcc;
ln = regcc->cur;
if (regmatch(cc->next))
- return TRUE;
+ sayYES;
regcc->cur = ln;
regcc = cc;
- return FALSE;
+ sayNO;
}
/* First just match a string of min scans. */
if (n < cc->min) {
cc->cur = n;
cc->lastloc = locinput;
- return regmatch(cc->scan);
+ if (regmatch(cc->scan))
+ sayYES;
+ cc->cur = n - 1;
+ sayNO;
}
/* Prefer next over scan for minimal matching. */
if (cc->minmod) {
regcc = cc->oldcc;
ln = regcc->cur;
- if (regmatch(cc->next))
- return TRUE; /* All done. */
+ cp = regcppush(cc->parenfloor);
+ if (regmatch(cc->next)) {
+ regcpblow(cp);
+ sayYES; /* All done. */
+ }
+ regcppop();
regcc->cur = ln;
regcc = cc;
if (n >= cc->max) /* Maximum greed exceeded? */
- return FALSE;
+ sayNO;
/* Try scanning more and see if it helps. */
reginput = locinput;
cc->cur = n;
cc->lastloc = locinput;
- return regmatch(cc->scan);
+ cp = regcppush(cc->parenfloor);
+ if (regmatch(cc->scan)) {
+ regcpblow(cp);
+ sayYES;
+ }
+ regcppop();
+ cc->cur = n - 1;
+ sayNO;
}
/* Prefer scan over next for maximal matching. */
if (n < cc->max) { /* More greed allowed? */
- regcppush(cc->parenfloor);
+ cp = regcppush(cc->parenfloor);
cc->cur = n;
cc->lastloc = locinput;
- if (regmatch(cc->scan))
- return TRUE;
+ if (regmatch(cc->scan)) {
+ regcpblow(cp);
+ sayYES;
+ }
regcppop(); /* Restore some previous $<digit>s? */
reginput = locinput;
}
regcc = cc->oldcc;
ln = regcc->cur;
if (regmatch(cc->next))
- return TRUE;
+ sayYES;
regcc->cur = ln;
regcc = cc;
- return FALSE;
+ cc->cur = n - 1;
+ sayNO;
}
/* NOT REACHED */
case BRANCH: {
do {
reginput = locinput;
if (regmatch(NEXTOPER(scan)))
- return 1;
+ sayYES;
for (n = *reglastparen; n > lastparen; n--)
regendp[n] = 0;
*reglastparen = n;
scan = regnext(scan);
#endif
} while (scan != NULL && OP(scan) == BRANCH);
- return 0;
+ sayNO;
/* NOTREACHED */
}
}
n = 32767;
scan = NEXTOPER(scan);
repeat:
- if (OP(next) == EXACTLY)
- nextchar = *(OPERAND(next)+1);
+ if (regkind[(U8)OP(next)] == EXACT) {
+ c1 = UCHARAT(OPERAND(next) + 1);
+ if (OP(next) == EXACTF)
+ c2 = fold[c1];
+ else if (OP(next) == EXACTFL)
+ c2 = fold_locale[c1];
+ else
+ c2 = c1;
+ }
else
- nextchar = -1000;
+ c1 = c2 = -1000;
reginput = locinput;
if (minmod) {
minmod = 0;
if (ln && regrepeat(scan, ln) < ln)
- return 0;
+ sayNO;
while (n >= ln || (n == 32767 && ln > 0)) { /* ln overflow ? */
/* If it could work, try it. */
- if (nextchar == -1000 || *reginput == nextchar)
+ if (c1 == -1000 ||
+ UCHARAT(reginput) == c1 ||
+ UCHARAT(reginput) == c2)
+ {
if (regmatch(next))
- return 1;
+ sayYES;
+ }
/* Couldn't or didn't -- back up. */
reginput = locinput + ln;
if (regrepeat(scan, 1)) {
reginput = locinput + ln;
}
else
- return 0;
+ sayNO;
}
}
else {
ln = n; /* why back off? */
while (n >= ln) {
/* If it could work, try it. */
- if (nextchar == -1000 || *reginput == nextchar)
+ if (c1 == -1000 ||
+ UCHARAT(reginput) == c1 ||
+ UCHARAT(reginput) == c2)
+ {
if (regmatch(next))
- return 1;
+ sayYES;
+ }
/* Couldn't or didn't -- back up. */
n--;
reginput = locinput + n;
}
}
- return 0;
+ sayNO;
case SUCCEED:
case END:
reginput = locinput; /* put where regtry can find it */
- return 1; /* Success! */
+ sayYES; /* Success! */
case IFMATCH:
reginput = locinput;
scan = NEXTOPER(scan);
if (!regmatch(scan))
- return 0;
+ sayNO;
break;
case UNLESSM:
reginput = locinput;
scan = NEXTOPER(scan);
if (regmatch(scan))
- return 0;
+ sayNO;
break;
default:
- fprintf(stderr, "%x %d\n",(unsigned)scan,scan[1]);
+ PerlIO_printf(PerlIO_stderr(), "%x %d\n",(unsigned)scan,scan[1]);
FAIL("regexp memory corruption");
}
scan = next;
*/
FAIL("corrupted regexp pointers");
/*NOTREACHED*/
+ sayNO;
+
+yes:
+#ifdef DEBUGGING
+ regindent--;
+#endif
+ return 1;
+
+no:
+#ifdef DEBUGGING
+ regindent--;
+#endif
return 0;
}
case SANY:
scan = loceol;
break;
- case EXACTLY: /* length of string is 1 */
- opnd++;
- while (scan < loceol && *opnd == *scan)
+ case EXACT: /* length of string is 1 */
+ c = UCHARAT(++opnd);
+ while (scan < loceol && UCHARAT(scan) == c)
+ scan++;
+ break;
+ case EXACTF: /* length of string is 1 */
+ c = UCHARAT(++opnd);
+ while (scan < loceol &&
+ (UCHARAT(scan) == c || UCHARAT(scan) == fold[c]))
+ scan++;
+ break;
+ case EXACTFL: /* length of string is 1 */
+ regtainted = TRUE;
+ c = UCHARAT(++opnd);
+ while (scan < loceol &&
+ (UCHARAT(scan) == c || UCHARAT(scan) == fold_locale[c]))
scan++;
break;
case ANYOF:
- c = UCHARAT(scan);
- while (scan < loceol && !(opnd[c >> 3] & (1 << (c & 7)))) {
+ while (scan < loceol && reginclass(opnd, *scan))
scan++;
- c = UCHARAT(scan);
- }
break;
case ALNUM:
while (scan < loceol && isALNUM(*scan))
scan++;
break;
+ case ALNUML:
+ regtainted = TRUE;
+ while (scan < loceol && isALNUM_LC(*scan))
+ scan++;
+ break;
case NALNUM:
while (scan < loceol && !isALNUM(*scan))
scan++;
break;
+ case NALNUML:
+ regtainted = TRUE;
+ while (scan < loceol && !isALNUM_LC(*scan))
+ scan++;
+ break;
case SPACE:
while (scan < loceol && isSPACE(*scan))
scan++;
break;
+ case SPACEL:
+ regtainted = TRUE;
+ while (scan < loceol && isSPACE_LC(*scan))
+ scan++;
+ break;
case NSPACE:
while (scan < loceol && !isSPACE(*scan))
scan++;
break;
+ case NSPACEL:
+ regtainted = TRUE;
+ while (scan < loceol && !isSPACE_LC(*scan))
+ scan++;
+ break;
case DIGIT:
while (scan < loceol && isDIGIT(*scan))
scan++;
}
/*
+ - regclass - determine if a character falls into a character class
+ */
+
+static bool
+reginclass(p, c)
+register char *p;
+register I32 c;
+{
+ char flags = *p;
+ bool match = FALSE;
+
+ c &= 0xFF;
+ if (p[1 + (c >> 3)] & (1 << (c & 7)))
+ match = TRUE;
+ else if (flags & ANYOF_FOLD) {
+ I32 cf;
+ if (flags & ANYOF_LOCALE) {
+ regtainted = TRUE;
+ cf = fold_locale[c];
+ }
+ else
+ cf = fold[c];
+ if (p[1 + (cf >> 3)] & (1 << (cf & 7)))
+ match = TRUE;
+ }
+
+ if (!match && (flags & ANYOF_ISA)) {
+ regtainted = TRUE;
+
+ if (((flags & ANYOF_ALNUML) && isALNUM_LC(c)) ||
+ ((flags & ANYOF_NALNUML) && !isALNUM_LC(c)) ||
+ ((flags & ANYOF_SPACEL) && isSPACE_LC(c)) ||
+ ((flags & ANYOF_NSPACEL) && !isSPACE_LC(c)))
+ {
+ match = TRUE;
+ }
+ }
+
+ return match ^ ((flags & ANYOF_INVERT) != 0);
+}
+
+/*
- regnext - dig the "next" pointer out of a node
*
* [Note, when REGALIGN is defined there are two places in regmatch()