/*-
* This code is derived from OpenBSD's libc/regex, original license follows:
*
* Copyright (c) 1992, 1993, 1994 Henry Spencer.
* Copyright (c) 1992, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Henry Spencer.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)engine.c 8.5 (Berkeley) 3/20/94
*/
/*
* The matching engine and friends. This file is #included by regexec.c
* after suitable #defines of a variety of macros used herein, so that
* different state representations can be used without duplicating masses
* of code.
*/
#ifdef SNAMES
#define matcher smatcher
#define fast sfast
#define slow sslow
#define dissect sdissect
#define backref sbackref
#define step sstep
#define print sprint
#define at sat
#define match smat
#define nope snope
#define step_back sstep_back
#endif
#ifdef LNAMES
#define matcher lmatcher
#define fast lfast
#define slow lslow
#define dissect ldissect
#define backref lbackref
#define step lstep
#define print lprint
#define at lat
#define match lmat
#define nope lnope
#define step_back lstep_back
#endif
/* another structure passed up and down to avoid zillions of parameters */
struct match {
struct re_guts *g;
int eflags;
llvm_regmatch_t *pmatch; /* [nsub+1] (0 element unused) */
const char *offp; /* offsets work from here */
const char *beginp; /* start of string -- virtual NUL precedes */
const char *endp; /* end of string -- virtual NUL here */
const char *coldp; /* can be no match starting before here */
const char **lastpos; /* [nplus+1] */
STATEVARS;
states st; /* current states */
states fresh; /* states for a fresh start */
states tmp; /* temporary */
states empty; /* empty set of states */
};
static int matcher(struct re_guts *, const char *, size_t,
llvm_regmatch_t[], int);
static const char *dissect(struct match *, const char *, const char *, sopno,
sopno);
static const char *backref(struct match *, const char *, const char *, sopno,
sopno, sopno, int);
static const char *fast(struct match *, const char *, const char *, sopno, sopno);
static const char *slow(struct match *, const char *, const char *, sopno, sopno);
static states step(struct re_guts *, sopno, sopno, states, int, states);
#define MAX_RECURSION 100
#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 CODEMAX (BOL+5) /* highest code used */
#define NONCHAR(c) ((c) > CHAR_MAX)
#define NNONCHAR (CODEMAX-CHAR_MAX)
#ifdef REDEBUG
static void print(struct match *, char *, states, int, FILE *);
#endif
#ifdef REDEBUG
static void at(struct match *, char *, char *, char *, sopno, sopno);
#endif
#ifdef REDEBUG
static char *pchar(int);
#endif
#ifdef REDEBUG
#define SP(t, s, c) print(m, t, s, c, stdout)
#define AT(t, p1, p2, s1, s2) at(m, t, p1, p2, s1, s2)
#define NOTE(str) { if (m->eflags®_TRACE) (void)printf("=%s\n", (str)); }
static int nope = 0;
#else
#define SP(t, s, c) /* nothing */
#define AT(t, p1, p2, s1, s2) /* nothing */
#define NOTE(s) /* nothing */
#endif
/*
- matcher - the actual matching engine
*/
static int /* 0 success, REG_NOMATCH failure */
matcher(struct re_guts *g, const char *string, size_t nmatch,
llvm_regmatch_t pmatch[],
int eflags)
{
const char *endp;
size_t i;
struct match mv;
struct match *m = &mv;
const char *dp;
const sopno gf = g->firststate+1; /* +1 for OEND */
const sopno gl = g->laststate;
const char *start;
const char *stop;
/* simplify the situation where possible */
if (g->cflags®_NOSUB)
nmatch = 0;
if (eflags®_STARTEND) {
start = string + pmatch[0].rm_so;
stop = string + pmatch[0].rm_eo;
} else {
start = string;
stop = start + strlen(start);
}
if (stop < start)
return(REG_INVARG);
/* prescreening; this does wonders for this rather slow code */
if (g->must != NULL) {
for (dp = start; dp < stop; dp++)
if (*dp == g->must[0] && stop - dp >= g->mlen &&
memcmp(dp, g->must, (size_t)g->mlen) == 0)
break;
if (dp == stop) /* we didn't find g->must */
return(REG_NOMATCH);
}
/* match struct setup */
m->g = g;
m->eflags = eflags;
m->pmatch = NULL;
m->lastpos = NULL;
m->offp = string;
m->beginp = start;
m->endp = stop;
STATESETUP(m, 4);
SETUP(m->st);
SETUP(m->fresh);
SETUP(m->tmp);
SETUP(m->empty);
CLEAR(m->empty);
/* this loop does only one repetition except for backrefs */
for (;;) {
endp = fast(m, start, stop, gf, gl);
if (endp == NULL) { /* a miss */
free(m->pmatch);
free((void*)m->lastpos);
STATETEARDOWN(m);
return(REG_NOMATCH);
}
if (nmatch == 0 && !g->backrefs)
break; /* no further info needed */
/* where? */
assert(m->coldp != NULL);
for (;;) {
NOTE("finding start");
endp = slow(m, m->coldp, stop, gf, gl);
if (endp != NULL)
break;
assert(m->coldp < m->endp);
m->coldp++;
}
if (nmatch == 1 && !g->backrefs)
break; /* no further info needed */
/* oh my, they want the subexpressions... */
if (m->pmatch == NULL)
m->pmatch = (llvm_regmatch_t *)malloc((m->g->nsub + 1) *
sizeof(llvm_regmatch_t));
if (m->pmatch == NULL) {
STATETEARDOWN(m);
return(REG_ESPACE);
}
for (i = 1; i <= m->g->nsub; i++)
m->pmatch[i].rm_so = m->pmatch[i].rm_eo = -1;
if (!g->backrefs && !(m->eflags®_BACKR)) {
NOTE("dissecting");
dp = dissect(m, m->coldp, endp, gf, gl);
} else {
if (g->nplus > 0 && m->lastpos == NULL)
m->lastpos = (const char **)malloc((g->nplus+1) *
sizeof(char *));
if (g->nplus > 0 && m->lastpos == NULL) {
free(m->pmatch);
STATETEARDOWN(m);
return(REG_ESPACE);
}
NOTE("backref dissect");
dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
}
if (dp != NULL)
break;
/* uh-oh... we couldn't find a subexpression-level match */
assert(g->backrefs); /* must be back references doing it */
assert(g->nplus == 0 || m->lastpos != NULL);
for (;;) {
if (dp != NULL || endp <= m->coldp)
break; /* defeat */
NOTE("backoff");
endp = slow(m, m->coldp, endp-1, gf, gl);
if (endp == NULL)
break; /* defeat */
/* try it on a shorter possibility */
#ifndef NDEBUG
for (i = 1; i <= m->g->nsub; i++) {
assert(m->pmatch[i].rm_so == -1);
assert(m->pmatch[i].rm_eo == -1);
}
#endif
NOTE("backoff dissect");
dp = backref(m, m->coldp, endp, gf, gl, (sopno)0, 0);
}
assert(dp == NULL || dp == endp);
if (dp != NULL) /* found a shorter one */
break;
/* despite initial appearances, there is no match here */
NOTE("false alarm");
if (m->coldp == stop)
break;
start = m->coldp + 1; /* recycle starting later */
}
/* fill in the details if requested */
if (nmatch > 0) {
pmatch[0].rm_so = m->coldp - m->offp;
pmatch[0].rm_eo = endp - m->offp;
}
if (nmatch > 1) {
assert(m->pmatch != NULL);
for (i = 1; i < nmatch; i++)
if (i <= m->g->nsub)
pmatch[i] = m->pmatch[i];
else {
pmatch[i].rm_so = -1;
pmatch[i].rm_eo = -1;
}
}
if (m->pmatch != NULL)
free((char *)m->pmatch);
if (m->lastpos != NULL)
free((char *)m->lastpos);
STATETEARDOWN(m);
return(0);
}
/* Step back from "stop" to a position where the strip startst..stopst might
* match. This can always conservatively return "stop - 1", but may return an
* earlier position if matches at later positions are impossible. */
static const char *
step_back(struct re_guts *g, const char *start, const char *stop, sopno startst,
sopno stopst)
{
/* Always step back at least one character. */
assert(stop > start);
const char *res = stop - 1;
/* Check whether the strip startst..stropst starts with a fixed character,
* ignoring any closing parentheses. If not, return a conservative result. */
for (;;) {
if (startst >= stopst)
return res;
if (OP(g->strip[startst]) != ORPAREN)
break;
startst++;
}
if (OP(g->strip[startst]) != OCHAR)
return res;
/* Find the character that starts the following match. */
char ch = OPND(g->strip[startst]);
for (; res != start; --res) {
if (*res == ch)
break;
}
return res;
}
/*
- dissect - figure out what matched what, no back references
*/
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 */
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++;
break;
case OBOL:
case OEOL:
case OBOW:
case OEOW:
break;
case OANY:
case OANYOF:
sp++;
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 = step_back(m->g, sp, rest, es, stopst);
assert(stp >= sp); /* it did work */
}
ssub = ss + 1;
esub = es - 1;
/* did innards match? */
if (slow(m, sp, rest, ssub, esub) != NULL) {
const char *dp = dissect(m, sp, rest, ssub, esub);
(void)dp; /* avoid warning if assertions off */
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 = step_back(m->g, sp, rest, es, stopst);
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);
{
const char *dp = dissect(m, ssp, sep, ssub, esub);
(void)dp; /* avoid warning if assertions off */
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);
}
{
const char *dp = dissect(m, sp, rest, ssub, esub);
(void)dp; /* avoid warning if assertions off */
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 * /* == stop (success) or NULL (failure) */
backref(struct match *m, const char *start, const char *stop, sopno startst,
sopno stopst, sopno lev, int rec) /* PLUS nesting level */
{
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;
llvm_regoff_t offsave;
cset *cs;
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 || *sp++ != (char)OPND(s))
return(NULL);
break;
case OANY:
if (sp == stop)
return(NULL);
sp++;
break;
case OANYOF:
cs = &m->g->sets[OPND(s)];
if (sp == stop || !CHIN(cs, *sp++))
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 NULL;
}
/*
- fast - step through the string at top speed
*/
static const char * /* where tentative match ended, or NULL */
fast(struct match *m, const char *start, const char *stop, sopno startst,
sopno stopst)
{
states st = m->st;
states fresh = m->fresh;
states tmp = m->tmp;
const char *p = start;
int c = (start == m->beginp) ? OUT : *(start-1);
int lastc; /* previous c */
int flagch;
int i;
const char *coldp; /* last p after which no match was underway */
CLEAR(st);
SET1(st, startst);
st = step(m->g, startst, stopst, st, NOTHING, st);
ASSIGN(fresh, st);
SP("start", st, *p);
coldp = NULL;
for (;;) {
/* next character */
lastc = c;
c = (p == m->endp) ? OUT : *p;
if (EQ(st, fresh))
coldp = p;
/* is there an EOL and/or BOL between lastc and c? */
flagch = '\0';
i = 0;
if ( (lastc == '\n' && m->g->cflags®_NEWLINE) ||
(lastc == OUT && !(m->eflags®_NOTBOL)) ) {
flagch = BOL;
i = m->g->nbol;
}
if ( (c == '\n' && m->g->cflags®_NEWLINE) ||
(c == OUT && !(m->eflags®_NOTEOL)) ) {
flagch = (flagch == BOL) ? BOLEOL : EOL;
i += m->g->neol;
}
if (i != 0) {
for (; i > 0; i--)
st = step(m->g, startst, stopst, st, flagch, st);
SP("boleol", st, c);
}
/* how about a word boundary? */
if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
(c != OUT && ISWORD(c)) ) {
flagch = BOW;
}
if ( (lastc != OUT && ISWORD(lastc)) &&
(flagch == EOL || (c != OUT && !ISWORD(c))) ) {
flagch = EOW;
}
if (flagch == BOW || flagch == EOW) {
st = step(m->g, startst, stopst, st, flagch, st);
SP("boweow", st, c);
}
/* are we done? */
if (ISSET(st, stopst) || p == stop)
break; /* NOTE BREAK OUT */
/* no, we must deal with this character */
ASSIGN(tmp, st);
ASSIGN(st, fresh);
assert(c != OUT);
st = step(m->g, startst, stopst, tmp, c, st);
SP("aft", st, c);
assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
p++;
}
assert(coldp != NULL);
m->coldp = coldp;
if (ISSET(st, stopst))
return(p+1);
else
return(NULL);
}
/*
- slow - step through the string more deliberately
*/
static const char * /* where it ended */
slow(struct match *m, const char *start, const char *stop, sopno startst,
sopno stopst)
{
states st = m->st;
states empty = m->empty;
states tmp = m->tmp;
const char *p = start;
int c = (start == m->beginp) ? OUT : *(start-1);
int lastc; /* previous c */
int flagch;
int i;
const char *matchp; /* last p at which a match ended */
AT("slow", start, stop, startst, stopst);
CLEAR(st);
SET1(st, startst);
SP("sstart", st, *p);
st = step(m->g, startst, stopst, st, NOTHING, st);
matchp = NULL;
for (;;) {
/* next character */
lastc = c;
c = (p == m->endp) ? OUT : *p;
/* is there an EOL and/or BOL between lastc and c? */
flagch = '\0';
i = 0;
if ( (lastc == '\n' && m->g->cflags®_NEWLINE) ||
(lastc == OUT && !(m->eflags®_NOTBOL)) ) {
flagch = BOL;
i = m->g->nbol;
}
if ( (c == '\n' && m->g->cflags®_NEWLINE) ||
(c == OUT && !(m->eflags®_NOTEOL)) ) {
flagch = (flagch == BOL) ? BOLEOL : EOL;
i += m->g->neol;
}
if (i != 0) {
for (; i > 0; i--)
st = step(m->g, startst, stopst, st, flagch, st);
SP("sboleol", st, c);
}
/* how about a word boundary? */
if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) &&
(c != OUT && ISWORD(c)) ) {
flagch = BOW;
}
if ( (lastc != OUT && ISWORD(lastc)) &&
(flagch == EOL || (c != OUT && !ISWORD(c))) ) {
flagch = EOW;
}
if (flagch == BOW || flagch == EOW) {
st = step(m->g, startst, stopst, st, flagch, st);
SP("sboweow", st, c);
}
/* are we done? */
if (ISSET(st, stopst))
matchp = p;
if (EQ(st, empty) || p == stop)
break; /* NOTE BREAK OUT */
/* no, we must deal with this character */
ASSIGN(tmp, st);
ASSIGN(st, empty);
assert(c != OUT);
st = step(m->g, startst, stopst, tmp, c, st);
SP("saft", st, c);
assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st));
p++;
}
return(matchp);
}
/*
- step - map set of states reachable before char to set reachable after
*/
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 */
int 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 != (char)OPND(s));
if (ch == (char)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);
}
#ifdef REDEBUG
/*
- print - print a set of states
*/
static void
print(struct match *m, char *caption, states st, int ch, FILE *d)
{
struct re_guts *g = m->g;
int i;
int first = 1;
if (!(m->eflags®_TRACE))
return;
(void)fprintf(d, "%s", caption);
if (ch != '\0')
(void)fprintf(d, " %s", pchar(ch));
for (i = 0; i < g->nstates; i++)
if (ISSET(st, i)) {
(void)fprintf(d, "%s%d", (first) ? "\t" : ", ", i);
first = 0;
}
(void)fprintf(d, "\n");
}
/*
- at - print current situation
*/
static void
at(struct match *m, char *title, char *start, char *stop, sopno startst,
sopno stopst)
{
if (!(m->eflags®_TRACE))
return;
(void)printf("%s %s-", title, pchar(*start));
(void)printf("%s ", pchar(*stop));
(void)printf("%ld-%ld\n", (long)startst, (long)stopst);
}
#ifndef PCHARDONE
#define PCHARDONE /* never again */
/*
- pchar - make a character printable
*
* Is this identical to regchar() over in debug.c? Well, yes. But a
* duplicate here avoids having a debugging-capable regexec.o tied to
* a matching debug.o, and this is convenient. It all disappears in
* the non-debug compilation anyway, so it doesn't matter much.
*/
static char * /* -> representation */
pchar(int ch)
{
static char pbuf[10];
if (isPrint(ch) || ch == ' ')
(void)snprintf(pbuf, sizeof pbuf, "%c", ch);
else
(void)snprintf(pbuf, sizeof pbuf, "\\%o", ch);
return(pbuf);
}
#endif
#endif
#undef matcher
#undef fast
#undef slow
#undef dissect
#undef backref
#undef step
#undef print
#undef at
#undef match
#undef nope
#undef step_back