/*
- matcher - the actual matching engine
== static int matcher(struct re_guts *g, const char *string, \
== size_t nmatch, regmatch_t pmatch[], int eflags);
*/
static int /* 0 success, REG_NOMATCH failure */
matcher(struct re_guts *g,
const char *string,
size_t nmatch,
regmatch_t pmatch[],
int eflags)
{
const char *endp;
int 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;
/* Boyer-Moore algorithms variables */
const char *pp;
int cj, mj;
const char *mustfirst;
const char *mustlast;
int *matchjump;
int *charjump;
/* 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) {
if (g->charjump != NULL && g->matchjump != NULL) {
mustfirst = g->must;
mustlast = g->must + g->mlen - 1;
charjump = g->charjump;
matchjump = g->matchjump;
pp = mustlast;
for (dp = start+g->mlen-1; dp < stop;) {
/* Fast skip non-matches */
while (dp < stop && charjump[(int)*dp])
dp += charjump[(int)*dp];
if (dp >= stop)
break;
/* Greedy matcher */
/* We depend on not being used for
* for strings of length 1
*/
while (*--dp == *--pp && pp != mustfirst);
if (*dp == *pp)
break;
/* Jump to next possible match */
mj = matchjump[pp - mustfirst];
cj = charjump[(int)*dp];
dp += (cj < mj ? mj : cj);
pp = mustlast;
}
if (pp != mustfirst)
return(REG_NOMATCH);
} 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);
ZAPSTATE(&m->mbs);
/* Adjust start according to moffset, to speed things up */
if (g->moffset > -1)
start = ((dp - g->moffset) < start) ? 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 */
if (m->pmatch != NULL)
free((char *)m->pmatch);
if (m->lastpos != NULL)
free((char *)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 += XMBRTOWC(NULL, m->coldp,
m->endp - m->coldp, &m->mbs, 0);
}
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®_BACKR)) {
NOTE("dissecting");
dp = dissect(m, m->coldp, endp, gf, gl);
} else {
if (g->nplus > 0 && m->lastpos == NULL)
m->lastpos = malloc((g->nplus+1) *
sizeof(const 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");
/* recycle starting later */
start = m->coldp + XMBRTOWC(NULL, m->coldp,
stop - m->coldp, &m->mbs, 0);
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);
}
/*
- matcher - the actual matching engine
*/
static int /* 0 success, R_REGEX_NOMATCH failure */
matcher(struct re_guts *g, char *string, size_t nmatch, RRegexMatch pmatch[],
int eflags)
{
char *endp;
int i;
struct match mv;
struct match *m = &mv;
char *dp;
const sopno gf = g->firststate+1; /* +1 for OEND */
const sopno gl = g->laststate;
char *start;
char *stop;
/* simplify the situation where possible */
if (g->cflags&R_REGEX_NOSUB)
nmatch = 0;
if (eflags&R_REGEX_STARTEND) {
start = string + pmatch[0].rm_so;
stop = string + pmatch[0].rm_eo;
} else {
start = string;
stop = start + strlen(start);
}
if (stop < start)
return(R_REGEX_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(R_REGEX_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(m->lastpos);
STATETEARDOWN(m);
return(R_REGEX_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 = (RRegexMatch *)malloc((m->g->nsub + 1) *
sizeof(RRegexMatch));
if (m->pmatch == NULL) {
STATETEARDOWN(m);
return(R_REGEX_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&R_REGEX_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(R_REGEX_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);
}
