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freebsd-skq/lib/libc/regex/engine.c
dcs 6ebebd878b Enhance the optimization provided by pre-matching. Fix style bugs with 
previous commits.

At the time we search the pattern for the "must" string, we now compute
the longest offset from the beginning of the pattern at which the must
string might be found. If that offset is found to be infinite (through
use of "+" or "*"), we set it to -1 to disable the heuristics applied
later.

After we are done with pre-matching, we use that offset and the point in
the text at which the must string was found to compute the earliest
point at which the pattern might be found.

Special care should be taken here. The variable "start" is passed to the
automata-processing functions fast() and slow() to indicate the point in
the text at which they should start working from. The real beginning of
the text is passed in a struct match variable m, which is used to check
for anchors. That variable, though, is initialized with "start", so we
must not adjust "start" before "m" is properly initialized.

Simple tests showed a speed increase from 100% to 400%, but they were
biased in that regexec() was called for the whole file instead of line
by line, and parenthized subexpressions were not searched for.

This change adds a single integer to the size of the "guts" structure,
and does not change the ABI.

Further improvements possible:

Since the speed increase observed here is so huge, one intuitive
optimization would be to introduce a bias in the function that computes
the "must" string so as to prefer a smaller string with a finite offset
over a larger one with an infinite offset. Tests have shown this to be a
bad idea, though, as the cost of false pre-matches far outweights the
benefits of a must offset, even in biased situations.

A number of other improvements suggest themselves, though:

	* identify the cases where the pattern is identical to the must
	string, and avoid entering fast() and slow() in these cases.

	* compute the maximum offset from the must string to the end of
	the pattern, and use that to set the point at which fast() and
	slow() should give up trying to find a match, and return then
	return to pre-matching.

	* return all the way to pre-matching if a "match" was found and
	later invalidated by back reference processing. Since back
	references are evil and should be avoided anyway, this is of
	little use.
2000-07-02 10:58:07 +00:00

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/*-
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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
*
* $FreeBSD$
*/
/*
* 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
#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
#endif
/* another structure passed up and down to avoid zillions of parameters */
struct match {
struct re_guts *g;
int eflags;
regmatch_t *pmatch; /* [nsub+1] (0 element unused) */
char *offp; /* offsets work from here */
char *beginp; /* start of string -- virtual NUL precedes */
char *endp; /* end of string -- virtual NUL here */
char *coldp; /* can be no match starting before here */
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 */
};
/* ========= begin header generated by ./mkh ========= */
#ifdef __cplusplus
extern "C" {
#endif
/* === engine.c === */
static int matcher __P((struct re_guts *g, char *string, size_t nmatch, regmatch_t pmatch[], int eflags));
static char *dissect __P((struct match *m, char *start, char *stop, sopno startst, sopno stopst));
static char *backref __P((struct match *m, char *start, char *stop, sopno startst, sopno stopst, sopno lev));
static char *fast __P((struct match *m, char *start, char *stop, sopno startst, sopno stopst));
static char *slow __P((struct match *m, char *start, char *stop, sopno startst, sopno stopst));
static states step __P((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 CODEMAX (BOL+5) /* highest code used */
#define NONCHAR(c) ((c) > CHAR_MAX)
#define NNONCHAR (CODEMAX-CHAR_MAX)
#ifdef REDEBUG
static void print __P((struct match *m, char *caption, states st, int ch, FILE *d));
#endif
#ifdef REDEBUG
static void at __P((struct match *m, char *title, char *start, char *stop, sopno startst, sopno stopst));
#endif
#ifdef REDEBUG
static char *pchar __P((int ch));
#endif
#ifdef __cplusplus
}
#endif
/* ========= end header generated by ./mkh ========= */
#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&REG_TRACE) printf("=%s\n", (str)); }
#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 matcher(register struct re_guts *g, char *string, \
== size_t nmatch, regmatch_t pmatch[], int eflags);
*/
static int /* 0 success, REG_NOMATCH failure */
matcher(g, string, nmatch, pmatch, eflags)
register struct re_guts *g;
char *string;
size_t nmatch;
regmatch_t pmatch[];
int eflags;
{
register char *endp;
register int i;
struct match mv;
register struct match *m = &mv;
register char *dp;
register const sopno gf = g->firststate+1; /* +1 for OEND */
register const sopno gl = g->laststate;
char *start;
char *stop;
/* Boyer-Moore algorithms variables */
register unsigned char *pp;
int cj, mj;
register unsigned char *mustfirst;
register unsigned char *mustlast;
register int mustlen;
register int *matchjump;
register int *charjump;
register unsigned char *bmp;
register unsigned char *bmps;
/* simplify the situation where possible */
if (g->cflags&REG_NOSUB)
nmatch = 0;
if (eflags&REG_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) {
if (g->charjump != NULL && g->matchjump != NULL) {
mustlen = -g->mlen;
mustfirst = g->must;
mustlast = g->must + g->mlen - 1;
charjump = g->charjump;
matchjump = g->matchjump;
bmps = stop;
pp = mustlast;
for (bmp = start+g->mlen-1; bmp < bmps;) {
/* Fast skip non-matches */
while (bmp < bmps && charjump[*bmp])
bmp += charjump[*bmp];
if (bmp >= bmps)
break;
/* Greedy matcher */
/* We depend on not being used for
* for strings of length 1
*/
while (*--bmp == *--pp && pp != mustfirst);
if (*bmp == *pp)
break;
/* Jump to next possible match */
mj = matchjump[pp - mustfirst];
cj = charjump[*bmp];
bmp += (cj < mj ? mj : cj);
pp = mustlast;
}
if (pp != mustfirst)
return(REG_NOMATCH);
dp = bmp;
} else {
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);
/* Adjust start according to moffset, to speed things up */
if (g->moffset > -1)
start = dp - g->moffset;
/* this loop does only one repetition except for backrefs */
for (;;) {
endp = fast(m, start, stop, gf, gl);
if (endp == NULL) { /* a miss */
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, he wants the subexpressions... */
if (m->pmatch == NULL)
m->pmatch = (regmatch_t *)malloc((m->g->nsub + 1) *
sizeof(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&REG_BACKR)) {
NOTE("dissecting");
dp = dissect(m, m->coldp, endp, gf, gl);
} else {
if (g->nplus > 0 && m->lastpos == NULL)
m->lastpos = (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);
}
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);
}
assert(dp == NULL || dp == endp);
if (dp != NULL) /* found a shorter one */
break;
/* despite initial appearances, there is no match here */
NOTE("false alarm");
start = m->coldp + 1; /* recycle starting later */
assert(start <= stop);
}
/* 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);
}
/*
- dissect - figure out what matched what, no back references
== static char *dissect(register struct match *m, char *start, \
== char *stop, sopno startst, sopno stopst);
*/
static char * /* == stop (success) always */
dissect(m, start, stop, startst, stopst)
register struct match *m;
char *start;
char *stop;
sopno startst;
sopno stopst;
{
register int i;
register sopno ss; /* start sop of current subRE */
register sopno es; /* end sop of current subRE */
register char *sp; /* start of string matched by it */
register char *stp; /* string matched by it cannot pass here */
register char *rest; /* start of rest of string */
register char *tail; /* string unmatched by rest of RE */
register sopno ssub; /* start sop of subsubRE */
register sopno esub; /* end sop of subsubRE */
register char *ssp; /* start of string matched by subsubRE */
register char *sep; /* end of string matched by subsubRE */
register char *oldssp; /* previous ssp */
register char *dp;
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 = 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 char *backref(register struct match *m, char *start, \
== char *stop, sopno startst, sopno stopst, sopno lev);
*/
static char * /* == stop (success) or NULL (failure) */
backref(m, start, stop, startst, stopst, lev)
register struct match *m;
char *start;
char *stop;
sopno startst;
sopno stopst;
sopno lev; /* PLUS nesting level */
{
register int i;
register sopno ss; /* start sop of current subRE */
register char *sp; /* start of string matched by it */
register sopno ssub; /* start sop of subsubRE */
register sopno esub; /* end sop of subsubRE */
register char *ssp; /* start of string matched by subsubRE */
register char *dp;
register size_t len;
register int hard;
register sop s;
register regoff_t offsave;
register 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&REG_NOTBOL)) ||
(sp < m->endp && *(sp-1) == '\n' &&
(m->g->cflags&REG_NEWLINE)) )
{ /* yes */ }
else
return(NULL);
break;
case OEOL:
if ( (sp == m->endp && !(m->eflags&REG_NOTEOL)) ||
(sp < m->endp && *sp == '\n' &&
(m->g->cflags&REG_NEWLINE)) )
{ /* yes */ }
else
return(NULL);
break;
case OBOW:
if (( (sp == m->beginp && !(m->eflags&REG_NOTBOL)) ||
(sp < m->endp && *(sp-1) == '\n' &&
(m->g->cflags&REG_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&REG_NOTEOL)) ||
(sp < m->endp && *sp == '\n' &&
(m->g->cflags&REG_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;
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));
break;
case OQUEST_: /* to null or not */
dp = backref(m, sp, stop, ss+1, stopst, lev);
if (dp != NULL)
return(dp); /* not */
return(backref(m, sp, stop, ss+OPND(s)+1, stopst, lev));
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));
break;
case O_PLUS:
if (sp == m->lastpos[lev]) /* last pass matched null */
return(backref(m, sp, stop, ss+1, stopst, lev-1));
/* try another pass */
m->lastpos[lev] = sp;
dp = backref(m, sp, stop, ss-OPND(s)+1, stopst, lev);
if (dp == NULL)
return(backref(m, sp, stop, ss+1, stopst, lev-1));
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);
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);
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);
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";
}
/*
- fast - step through the string at top speed
== static char *fast(register struct match *m, char *start, \
== char *stop, sopno startst, sopno stopst);
*/
static char * /* where tentative match ended, or NULL */
fast(m, start, stop, startst, stopst)
register struct match *m;
char *start;
char *stop;
sopno startst;
sopno stopst;
{
register states st = m->st;
register states fresh = m->fresh;
register states tmp = m->tmp;
register char *p = start;
register int c = (start == m->beginp) ? OUT : *(start-1);
register int lastc; /* previous c */
register int flagch;
register int i;
register 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&REG_NEWLINE) ||
(lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
flagch = BOL;
i = m->g->nbol;
}
if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
(c == OUT && !(m->eflags&REG_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 char *slow(register struct match *m, char *start, \
== char *stop, sopno startst, sopno stopst);
*/
static char * /* where it ended */
slow(m, start, stop, startst, stopst)
register struct match *m;
char *start;
char *stop;
sopno startst;
sopno stopst;
{
register states st = m->st;
register states empty = m->empty;
register states tmp = m->tmp;
register char *p = start;
register int c = (start == m->beginp) ? OUT : *(start-1);
register int lastc; /* previous c */
register int flagch;
register int i;
register 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&REG_NEWLINE) ||
(lastc == OUT && !(m->eflags&REG_NOTBOL)) ) {
flagch = BOL;
i = m->g->nbol;
}
if ( (c == '\n' && m->g->cflags&REG_NEWLINE) ||
(c == OUT && !(m->eflags&REG_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(register struct re_guts *g, sopno start, sopno stop, \
== register states bef, int ch, register 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 CODEMAX (BOL+5) // highest code used
== #define NONCHAR(c) ((c) > CHAR_MAX)
== #define NNONCHAR (CODEMAX-CHAR_MAX)
*/
static states
step(g, start, stop, bef, ch, aft)
register struct re_guts *g;
sopno start; /* start state within strip */
sopno stop; /* state after stop state within strip */
register states bef; /* states reachable before */
int ch; /* character or NONCHAR code */
register states aft; /* states already known reachable after */
{
register cset *cs;
register sop s;
register sopno pc;
register onestate here; /* note, macros know this name */
register sopno look;
register 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
== #ifdef REDEBUG
== static void print(struct match *m, char *caption, states st, \
== int ch, FILE *d);
== #endif
*/
static void
print(m, caption, st, ch, d)
struct match *m;
char *caption;
states st;
int ch;
FILE *d;
{
register struct re_guts *g = m->g;
register int i;
register int first = 1;
if (!(m->eflags&REG_TRACE))
return;
fprintf(d, "%s", caption);
if (ch != '\0')
fprintf(d, " %s", pchar(ch));
for (i = 0; i < g->nstates; i++)
if (ISSET(st, i)) {
fprintf(d, "%s%d", (first) ? "\t" : ", ", i);
first = 0;
}
fprintf(d, "\n");
}
/*
- at - print current situation
== #ifdef REDEBUG
== static void at(struct match *m, char *title, char *start, char *stop, \
== sopno startst, sopno stopst);
== #endif
*/
static void
at(m, title, start, stop, startst, stopst)
struct match *m;
char *title;
char *start;
char *stop;
sopno startst;
sopno stopst;
{
if (!(m->eflags&REG_TRACE))
return;
printf("%s %s-", title, pchar(*start));
printf("%s ", pchar(*stop));
printf("%ld-%ld\n", (long)startst, (long)stopst);
}
#ifndef PCHARDONE
#define PCHARDONE /* never again */
/*
- pchar - make a character printable
== #ifdef REDEBUG
== static char *pchar(int ch);
== #endif
*
* 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(ch)
int ch;
{
static char pbuf[10];
if (isprint((uch)ch) || ch == ' ')
sprintf(pbuf, "%c", ch);
else
sprintf(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
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