/*
- findmust - fill in must and mlen with longest mandatory literal string
*
* This algorithm could do fancy things like analyzing the operands of |
* for common subsequences. Someday. This code is simple and finds most
* of the interesting cases.
*
* Note that must and mlen got initialized during setup.
*/
static void
findmust(struct parse *p, struct re_guts *g)
{
sop *scan;
sop *start; /* start initialized in the default case, after that */
sop *newstart; /* newstart was initialized in the OCHAR case */
sopno newlen;
sop s;
char *cp;
sopno i;
/* avoid making error situations worse */
if (p->error != 0)
return;
/* find the longest OCHAR sequence in strip */
newlen = 0;
scan = g->strip + 1;
do {
s = *scan++;
switch (OP(s)) {
case OCHAR: /* sequence member */
if (newlen == 0) /* new sequence */
newstart = scan - 1;
newlen++;
break;
case OPLUS_: /* things that don't break one */
case OLPAREN:
case ORPAREN:
break;
case OQUEST_: /* things that must be skipped */
case OCH_:
scan--;
do {
scan += OPND(s);
s = *scan;
/* assert() interferes w debug printouts */
if (OP(s) != O_QUEST && OP(s) != O_CH &&
OP(s) != OOR2) {
g->iflags |= REGEX_BAD;
return;
}
} while (OP(s) != O_QUEST && OP(s) != O_CH);
/* fallthrough */
default: /* things that break a sequence */
if (newlen > g->mlen) { /* ends one */
start = newstart;
g->mlen = newlen;
}
newlen = 0;
break;
}
} while (OP(s) != OEND);
if (g->mlen == 0) /* there isn't one */
return;
/* turn it into a character string */
g->must = cli_malloc((size_t)g->mlen + 1);
if (g->must == NULL) { /* argh; just forget it */
g->mlen = 0;
return;
}
cp = g->must;
scan = start;
for (i = g->mlen; i > 0; i--) {
while (OP(s = *scan++) != OCHAR)
continue;
assert(cp < g->must + g->mlen);
*cp++ = (char)OPND(s);
}
assert(cp == g->must + g->mlen);
*cp++ = '\0'; /* just on general principles */
}
/*
- step - map set of states reachable before char to set reachable after
== static states step(struct re_guts *g, sopno start, sopno stop, \
== states bef, int ch, states aft);
== #define BOL (OUT-1)
== #define EOL (BOL-1)
== #define BOLEOL (BOL-2)
== #define NOTHING (BOL-3)
== #define BOW (BOL-4)
== #define EOW (BOL-5)
== #define BADCHAR (BOL-6)
== #define NONCHAR(c) ((c) <= OUT)
*/
static states
step(struct re_guts *g,
sopno start, /* start state within strip */
sopno stop, /* state after stop state within strip */
states bef, /* states reachable before */
wint_t ch, /* character or NONCHAR code */
states aft) /* states already known reachable after */
{
cset *cs;
sop s;
sopno pc;
onestate here; /* note, macros know this name */
sopno look;
int i;
for (pc = start, INIT(here, pc); pc != stop; pc++, INC(here)) {
s = g->strip[pc];
switch (OP(s)) {
case OEND:
assert(pc == stop-1);
break;
case OCHAR:
/* only characters can match */
assert(!NONCHAR(ch) || ch != OPND(s));
if (ch == OPND(s))
FWD(aft, bef, 1);
break;
case OBOL:
if (ch == BOL || ch == BOLEOL)
FWD(aft, bef, 1);
break;
case OEOL:
if (ch == EOL || ch == BOLEOL)
FWD(aft, bef, 1);
break;
case OBOW:
if (ch == BOW)
FWD(aft, bef, 1);
break;
case OEOW:
if (ch == EOW)
FWD(aft, bef, 1);
break;
case OANY:
if (!NONCHAR(ch))
FWD(aft, bef, 1);
break;
case OANYOF:
cs = &g->sets[OPND(s)];
if (!NONCHAR(ch) && CHIN(cs, ch))
FWD(aft, bef, 1);
break;
case OBACK_: /* ignored here */
case O_BACK:
FWD(aft, aft, 1);
break;
case OPLUS_: /* forward, this is just an empty */
FWD(aft, aft, 1);
break;
case O_PLUS: /* both forward and back */
FWD(aft, aft, 1);
i = ISSETBACK(aft, OPND(s));
BACK(aft, aft, OPND(s));
if (!i && ISSETBACK(aft, OPND(s))) {
/* oho, must reconsider loop body */
pc -= OPND(s) + 1;
INIT(here, pc);
}
break;
case OQUEST_: /* two branches, both forward */
FWD(aft, aft, 1);
FWD(aft, aft, OPND(s));
break;
case O_QUEST: /* just an empty */
FWD(aft, aft, 1);
break;
case OLPAREN: /* not significant here */
case ORPAREN:
FWD(aft, aft, 1);
break;
case OCH_: /* mark the first two branches */
FWD(aft, aft, 1);
assert(OP(g->strip[pc+OPND(s)]) == OOR2);
FWD(aft, aft, OPND(s));
break;
case OOR1: /* done a branch, find the O_CH */
if (ISSTATEIN(aft, here)) {
for (look = 1;
OP(s = g->strip[pc+look]) != O_CH;
look += OPND(s))
assert(OP(s) == OOR2);
FWD(aft, aft, look);
}
break;
case OOR2: /* propagate OCH_'s marking */
FWD(aft, aft, 1);
if (OP(g->strip[pc+OPND(s)]) != O_CH) {
assert(OP(g->strip[pc+OPND(s)]) == OOR2);
FWD(aft, aft, OPND(s));
}
break;
case O_CH: /* just empty */
FWD(aft, aft, 1);
break;
default: /* ooooops... */
assert(nope);
break;
}
}
return(aft);
}
/*
- dissect - figure out what matched what, no back references
== static const char *dissect(struct match *m, const char *start, \
== const char *stop, sopno startst, sopno stopst);
*/
static const char * /* == stop (success) always */
dissect(struct match *m,
const char *start,
const char *stop,
sopno startst,
sopno stopst)
{
int i;
sopno ss; /* start sop of current subRE */
sopno es; /* end sop of current subRE */
const char *sp; /* start of string matched by it */
const char *stp; /* string matched by it cannot pass here */
const char *rest; /* start of rest of string */
const char *tail; /* string unmatched by rest of RE */
sopno ssub; /* start sop of subsubRE */
sopno esub; /* end sop of subsubRE */
const char *ssp; /* start of string matched by subsubRE */
const char *sep; /* end of string matched by subsubRE */
const char *oldssp; /* previous ssp */
const char *dp __unused; /* actually used for assert checks */
AT("diss", start, stop, startst, stopst);
sp = start;
for (ss = startst; ss < stopst; ss = es) {
/* identify end of subRE */
es = ss;
switch (OP(m->g->strip[es])) {
case OPLUS_:
case OQUEST_:
es += OPND(m->g->strip[es]);
break;
case OCH_:
while (OP(m->g->strip[es]) != O_CH)
es += OPND(m->g->strip[es]);
break;
}
es++;
/* figure out what it matched */
switch (OP(m->g->strip[ss])) {
case OEND:
assert(nope);
break;
case OCHAR:
sp += XMBRTOWC(NULL, sp, stop - start, &m->mbs, 0);
break;
case OBOL:
case OEOL:
case OBOW:
case OEOW:
break;
case OANY:
case OANYOF:
sp += XMBRTOWC(NULL, sp, stop - start, &m->mbs, 0);
break;
case OBACK_:
case O_BACK:
assert(nope);
break;
/* cases where length of match is hard to find */
case OQUEST_:
stp = stop;
for (;;) {
/* how long could this one be? */
rest = slow(m, sp, stp, ss, es);
assert(rest != NULL); /* it did match */
/* could the rest match the rest? */
tail = slow(m, rest, stop, es, stopst);
if (tail == stop)
break; /* yes! */
/* no -- try a shorter match for this one */
stp = rest - 1;
assert(stp >= sp); /* it did work */
}
ssub = ss + 1;
esub = es - 1;
/* did innards match? */
if (slow(m, sp, rest, ssub, esub) != NULL) {
dp = dissect(m, sp, rest, ssub, esub);
assert(dp == rest);
} else /* no */
assert(sp == rest);
sp = rest;
break;
case OPLUS_:
stp = stop;
for (;;) {
/* how long could this one be? */
rest = slow(m, sp, stp, ss, es);
assert(rest != NULL); /* it did match */
/* could the rest match the rest? */
tail = slow(m, rest, stop, es, stopst);
if (tail == stop)
break; /* yes! */
/* no -- try a shorter match for this one */
stp = rest - 1;
assert(stp >= sp); /* it did work */
}
ssub = ss + 1;
esub = es - 1;
ssp = sp;
oldssp = ssp;
for (;;) { /* find last match of innards */
sep = slow(m, ssp, rest, ssub, esub);
if (sep == NULL || sep == ssp)
break; /* failed or matched null */
oldssp = ssp; /* on to next try */
ssp = sep;
}
if (sep == NULL) {
/* last successful match */
sep = ssp;
ssp = oldssp;
}
assert(sep == rest); /* must exhaust substring */
assert(slow(m, ssp, sep, ssub, esub) == rest);
dp = dissect(m, ssp, sep, ssub, esub);
assert(dp == sep);
sp = rest;
break;
case OCH_:
stp = stop;
for (;;) {
/* how long could this one be? */
rest = slow(m, sp, stp, ss, es);
assert(rest != NULL); /* it did match */
/* could the rest match the rest? */
tail = slow(m, rest, stop, es, stopst);
if (tail == stop)
break; /* yes! */
/* no -- try a shorter match for this one */
stp = rest - 1;
assert(stp >= sp); /* it did work */
}
ssub = ss + 1;
esub = ss + OPND(m->g->strip[ss]) - 1;
assert(OP(m->g->strip[esub]) == OOR1);
for (;;) { /* find first matching branch */
if (slow(m, sp, rest, ssub, esub) == rest)
break; /* it matched all of it */
/* that one missed, try next one */
assert(OP(m->g->strip[esub]) == OOR1);
esub++;
assert(OP(m->g->strip[esub]) == OOR2);
ssub = esub + 1;
esub += OPND(m->g->strip[esub]);
if (OP(m->g->strip[esub]) == OOR2)
esub--;
else
assert(OP(m->g->strip[esub]) == O_CH);
}
dp = dissect(m, sp, rest, ssub, esub);
assert(dp == rest);
sp = rest;
break;
case O_PLUS:
case O_QUEST:
case OOR1:
case OOR2:
case O_CH:
assert(nope);
break;
case OLPAREN:
i = OPND(m->g->strip[ss]);
assert(0 < i && i <= m->g->nsub);
m->pmatch[i].rm_so = sp - m->offp;
break;
case ORPAREN:
i = OPND(m->g->strip[ss]);
assert(0 < i && i <= m->g->nsub);
m->pmatch[i].rm_eo = sp - m->offp;
break;
default: /* uh oh */
assert(nope);
break;
}
}
assert(sp == stop);
return(sp);
}
/*
- backref - figure out what matched what, figuring in back references
== static const char *backref(struct match *m, const char *start, \
== const char *stop, sopno startst, sopno stopst, sopno lev);
*/
static const char * /* == stop (success) or NULL (failure) */
backref(struct match *m,
const char *start,
const char *stop,
sopno startst,
sopno stopst,
sopno lev, /* PLUS nesting level */
int rec)
{
int i;
sopno ss; /* start sop of current subRE */
const char *sp; /* start of string matched by it */
sopno ssub; /* start sop of subsubRE */
sopno esub; /* end sop of subsubRE */
const char *ssp; /* start of string matched by subsubRE */
const char *dp;
size_t len;
int hard;
sop s;
regoff_t offsave;
cset *cs;
wint_t wc;
AT("back", start, stop, startst, stopst);
sp = start;
/* get as far as we can with easy stuff */
hard = 0;
for (ss = startst; !hard && ss < stopst; ss++)
switch (OP(s = m->g->strip[ss])) {
case OCHAR:
if (sp == stop)
return(NULL);
sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
if (wc != OPND(s))
return(NULL);
break;
case OANY:
if (sp == stop)
return(NULL);
sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
if (wc == BADCHAR)
return (NULL);
break;
case OANYOF:
if (sp == stop)
return (NULL);
cs = &m->g->sets[OPND(s)];
sp += XMBRTOWC(&wc, sp, stop - sp, &m->mbs, BADCHAR);
if (wc == BADCHAR || !CHIN(cs, wc))
return(NULL);
break;
case OBOL:
if ( (sp == m->beginp && !(m->eflags®_NOTBOL)) ||
(sp < m->endp && *(sp-1) == '\n' &&
(m->g->cflags®_NEWLINE)) )
{ /* yes */ }
else
return(NULL);
break;
case OEOL:
if ( (sp == m->endp && !(m->eflags®_NOTEOL)) ||
(sp < m->endp && *sp == '\n' &&
(m->g->cflags®_NEWLINE)) )
{ /* yes */ }
else
return(NULL);
break;
case OBOW:
if (( (sp == m->beginp && !(m->eflags®_NOTBOL)) ||
(sp < m->endp && *(sp-1) == '\n' &&
(m->g->cflags®_NEWLINE)) ||
(sp > m->beginp &&
!ISWORD(*(sp-1))) ) &&
(sp < m->endp && ISWORD(*sp)) )
{ /* yes */ }
else
return(NULL);
break;
case OEOW:
if (( (sp == m->endp && !(m->eflags®_NOTEOL)) ||
(sp < m->endp && *sp == '\n' &&
(m->g->cflags®_NEWLINE)) ||
(sp < m->endp && !ISWORD(*sp)) ) &&
(sp > m->beginp && ISWORD(*(sp-1))) )
{ /* yes */ }
else
return(NULL);
break;
case O_QUEST:
break;
case OOR1: /* matches null but needs to skip */
ss++;
s = m->g->strip[ss];
do {
assert(OP(s) == OOR2);
ss += OPND(s);
} while (OP(s = m->g->strip[ss]) != O_CH);
/* note that the ss++ gets us past the O_CH */
break;
default: /* have to make a choice */
hard = 1;
break;
}
if (!hard) { /* that was it! */
if (sp != stop)
return(NULL);
return(sp);
}
ss--; /* adjust for the for's final increment */
/* the hard stuff */
AT("hard", sp, stop, ss, stopst);
s = m->g->strip[ss];
switch (OP(s)) {
case OBACK_: /* the vilest depths */
i = OPND(s);
assert(0 < i && i <= m->g->nsub);
if (m->pmatch[i].rm_eo == -1)
return(NULL);
assert(m->pmatch[i].rm_so != -1);
len = m->pmatch[i].rm_eo - m->pmatch[i].rm_so;
if (len == 0 && rec++ > MAX_RECURSION)
return(NULL);
assert(stop - m->beginp >= len);
if (sp > stop - len)
return(NULL); /* not enough left to match */
ssp = m->offp + m->pmatch[i].rm_so;
if (memcmp(sp, ssp, len) != 0)
return(NULL);
while (m->g->strip[ss] != SOP(O_BACK, i))
ss++;
return(backref(m, sp+len, stop, ss+1, stopst, lev, rec));
break;
case OQUEST_: /* to null or not */
dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
if (dp != NULL)
return(dp); /* not */
return(backref(m, sp, stop, ss+OPND(s)+1, stopst, lev, rec));
break;
case OPLUS_:
assert(m->lastpos != NULL);
assert(lev+1 <= m->g->nplus);
m->lastpos[lev+1] = sp;
return(backref(m, sp, stop, ss+1, stopst, lev+1, rec));
break;
case O_PLUS:
if (sp == m->lastpos[lev]) /* last pass matched null */
return(backref(m, sp, stop, ss+1, stopst, lev-1, rec));
/* try another pass */
m->lastpos[lev] = sp;
dp = backref(m, sp, stop, ss-OPND(s)+1, stopst, lev, rec);
if (dp == NULL)
return(backref(m, sp, stop, ss+1, stopst, lev-1, rec));
else
return(dp);
break;
case OCH_: /* find the right one, if any */
ssub = ss + 1;
esub = ss + OPND(s) - 1;
assert(OP(m->g->strip[esub]) == OOR1);
for (;;) { /* find first matching branch */
dp = backref(m, sp, stop, ssub, esub, lev, rec);
if (dp != NULL)
return(dp);
/* that one missed, try next one */
if (OP(m->g->strip[esub]) == O_CH)
return(NULL); /* there is none */
esub++;
assert(OP(m->g->strip[esub]) == OOR2);
ssub = esub + 1;
esub += OPND(m->g->strip[esub]);
if (OP(m->g->strip[esub]) == OOR2)
esub--;
else
assert(OP(m->g->strip[esub]) == O_CH);
}
break;
case OLPAREN: /* must undo assignment if rest fails */
i = OPND(s);
assert(0 < i && i <= m->g->nsub);
offsave = m->pmatch[i].rm_so;
m->pmatch[i].rm_so = sp - m->offp;
dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
if (dp != NULL)
return(dp);
m->pmatch[i].rm_so = offsave;
return(NULL);
break;
case ORPAREN: /* must undo assignment if rest fails */
i = OPND(s);
assert(0 < i && i <= m->g->nsub);
offsave = m->pmatch[i].rm_eo;
m->pmatch[i].rm_eo = sp - m->offp;
dp = backref(m, sp, stop, ss+1, stopst, lev, rec);
if (dp != NULL)
return(dp);
m->pmatch[i].rm_eo = offsave;
return(NULL);
break;
default: /* uh oh */
assert(nope);
break;
}
/* "can't happen" */
assert(nope);
/* NOTREACHED */
return "shut up gcc";
}
/*
* s_print - print the strip for debugging
*/
static void
s_print(struct re_guts *g, FILE *d)
{
sop *s;
cset *cs;
int done = 0;
sop opnd;
int col = 0;
ssize_t last;
sopno offset = 2;
# define GAP() { if (offset % 5 == 0) { \
if (col > 40) { \
fprintf(d, "\n\t"); \
col = 0; \
} else { \
fprintf(d, " "); \
col++; \
} \
} else \
col++; \
offset++; \
}
if (OP(g->strip[0]) != OEND)
fprintf(d, "missing initial OEND!\n");
for (s = &g->strip[1]; !done; s++) {
opnd = OPND(*s);
switch (OP(*s)) {
case OEND:
fprintf(d, "\n");
done = 1;
break;
case OCHAR:
if (strchr("\\|()^$.[+*?{}!<> ", (char)opnd) != NULL)
fprintf(d, "\\%c", (char)opnd);
else
fprintf(d, "%s", regchar((char)opnd));
break;
case OBOL:
fprintf(d, "^");
break;
case OEOL:
fprintf(d, "$");
break;
case OBOW:
fprintf(d, "\\{");
break;
case OEOW:
fprintf(d, "\\}");
break;
case OANY:
fprintf(d, ".");
break;
case OANYOF:
fprintf(d, "[(%ld)", (long)opnd);
#ifdef __NetBSD__
cs = &g->sets[opnd];
last = -1;
for (size_t i = 0; i < g->csetsize+1; i++) /* +1 flushes */
if (CHIN(cs, i) && i < g->csetsize) {
if (last < 0) {
fprintf(d, "%s", regchar(i));
last = i;
}
} else {
if (last >= 0) {
if (last != (ssize_t)i - 1)
fprintf(d, "-%s",
regchar(i - 1));
last = -1;
}
}
#endif
fprintf(d, "]");
break;
case OBACK_:
fprintf(d, "(\\<%ld>", (long)opnd);
break;
case O_BACK:
fprintf(d, "<%ld>\\)", (long)opnd);
break;
case OPLUS_:
fprintf(d, "(+");
if (OP(*(s+opnd)) != O_PLUS)
fprintf(d, "<%ld>", (long)opnd);
break;
case O_PLUS:
if (OP(*(s-opnd)) != OPLUS_)
fprintf(d, "<%ld>", (long)opnd);
fprintf(d, "+)");
break;
case OQUEST_:
fprintf(d, "(?");
if (OP(*(s+opnd)) != O_QUEST)
fprintf(d, "<%ld>", (long)opnd);
break;
case O_QUEST:
if (OP(*(s-opnd)) != OQUEST_)
fprintf(d, "<%ld>", (long)opnd);
fprintf(d, "?)");
break;
case OLPAREN:
fprintf(d, "((<%ld>", (long)opnd);
break;
case ORPAREN:
fprintf(d, "<%ld>))", (long)opnd);
break;
case OCH_:
fprintf(d, "<");
if (OP(*(s+opnd)) != OOR2)
fprintf(d, "<%ld>", (long)opnd);
break;
case OOR1:
if (OP(*(s-opnd)) != OOR1 && OP(*(s-opnd)) != OCH_)
fprintf(d, "<%ld>", (long)opnd);
fprintf(d, "|");
break;
case OOR2:
fprintf(d, "|");
if (OP(*(s+opnd)) != OOR2 && OP(*(s+opnd)) != O_CH)
fprintf(d, "<%ld>", (long)opnd);
break;
case O_CH:
if (OP(*(s-opnd)) != OOR1)
fprintf(d, "<%ld>", (long)opnd);
fprintf(d, ">");
break;
default:
#ifdef __FreeBSD__
fprintf(d, "!%ld(%ld)!", OP(*s), opnd);
#else
fprintf(d, "!%d(%d)!", OP(*s), opnd);
#endif
break;
}
if (!done)
GAP();
}
}
