fa *mkdfa(const char *s, int anchor) /* does the real work of making a dfa */
/* anchor = 1 for anchored matches, else 0 */
{
Node *p, *p1;
fa *f;
p = reparse(s);
p1 = op2(CAT, op2(STAR, op2(ALL, NIL, NIL), NIL), p);
/* put ALL STAR in front of reg. exp. */
p1 = op2(CAT, p1, op2(FINAL, NIL, NIL));
/* put FINAL after reg. exp. */
poscnt = 0;
penter(p1); /* enter parent pointers and leaf indices */
if ((f = (fa *) calloc(1, sizeof(fa) + poscnt*sizeof(rrow))) == NULL)
overflo("out of space for fa");
f->accept = poscnt-1; /* penter has computed number of positions in re */
cfoll(f, p1); /* set up follow sets */
freetr(p1);
if ((f->posns[0] = (int *) calloc(1, *(f->re[0].lfollow)*sizeof(int))) == NULL)
overflo("out of space in makedfa");
if ((f->posns[1] = (int *) calloc(1, sizeof(int))) == NULL)
overflo("out of space in makedfa");
*f->posns[1] = 0;
f->initstat = makeinit(f, anchor);
f->anchor = anchor;
f->restr = (uschar *) tostring(s);
return f;
}
void
cfail() {
struct words *queue[QSIZE];
struct words **front, **rear;
struct words *state;
int bstart;
char c;
struct words *s;
s = w;
front = rear = queue;
init: if ((s->inp) != 0) {
*rear++ = s->nst;
if (rear >= &queue[QSIZE - 1])
overflo();
}
if ((s = s->link) != 0) {
goto init;
}
while (rear != front) {
s = *front;
if (front == &queue[QSIZE-1])
front = queue;
else front++;
cloop: if ((c = s->inp) != 0) {
bstart = 0;
*rear = (q = s->nst);
if (front < rear)
if (rear >= &queue[QSIZE-1])
if (front == queue) overflo();
else rear = queue;
else rear++;
else
if (++rear == front) overflo();
state = s->fail;
floop: if (state == 0) {
state = w;
bstart = 1;
}
if (state->inp == c) {
qloop: q->fail = state->nst;
if ((state->nst)->out == 1)
q->out = 1;
if ((q = q->link) != 0)
goto qloop;
}
else if ((state = state->link) != 0)
goto floop;
else if (bstart == 0){
state = 0;
goto floop;
}
}
if ((s = s->link) != 0)
goto cloop;
}
}
int makeinit(fa *f, int anchor)
{
int i, k;
f->curstat = 2;
f->out[2] = 0;
f->reset = 0;
k = *(f->re[0].lfollow);
xfree(f->posns[2]);
if ((f->posns[2] = (int *) calloc(1, (k+1)*sizeof(int))) == NULL)
overflo("out of space in makeinit");
for (i=0; i <= k; i++) {
(f->posns[2])[i] = (f->re[0].lfollow)[i];
}
if ((f->posns[2])[1] == f->accept)
f->out[2] = 1;
for (i=0; i < NCHARS; i++)
f->gototab[2][i] = 0;
f->curstat = cgoto(f, 2, HAT);
if (anchor) {
*f->posns[2] = k-1; /* leave out position 0 */
for (i=0; i < k; i++) {
(f->posns[0])[i] = (f->posns[2])[i];
}
f->out[0] = f->out[2];
if (f->curstat != 2)
--(*f->posns[f->curstat]);
}
return f->curstat;
}
int pmatch(fa *f, const char *p0) /* longest match, for sub */
{
int s, ns;
uschar *p = (uschar *) p0;
uschar *q;
int i, k;
/* s = f->reset ? makeinit(f,1) : f->initstat; */
if (f->reset) {
f->initstat = s = makeinit(f,1);
} else {
s = f->initstat;
}
patbeg = (char *) p;
patlen = -1;
do {
q = p;
do {
if (f->out[s]) /* final state */
patlen = q-p;
/* assert(*q < NCHARS); */
if ((ns = f->gototab[s][*q]) != 0)
s = ns;
else
s = cgoto(f, s, *q);
if (s == 1) { /* no transition */
if (patlen >= 0) {
patbeg = (char *) p;
return(1);
}
else
goto nextin; /* no match */
}
} while (*q++ != 0);
if (f->out[s])
patlen = q-p-1; /* don't count $ */
if (patlen >= 0) {
patbeg = (char *) p;
return(1);
}
nextin:
s = 2;
if (f->reset) {
for (i = 2; i <= f->curstat; i++)
xfree(f->posns[i]);
k = *f->posns[0];
if ((f->posns[2] = (int *) calloc(1, (k+1)*sizeof(int))) == NULL)
overflo("out of space in pmatch");
for (i = 0; i <= k; i++)
(f->posns[2])[i] = (f->posns[0])[i];
f->initstat = f->curstat = 2;
f->out[2] = f->out[0];
for (i = 0; i < NCHARS; i++)
f->gototab[2][i] = 0;
}
} while (*p++ != 0);
return (0);
}
void cfoll(fa *f, Node *v) /* enter follow set of each leaf of vertex v into lfollow[leaf] */
{
int i;
int *p;
switch (type(v)) {
ELEAF
LEAF
f->re[info(v)].ltype = type(v);
f->re[info(v)].lval.np = right(v);
while (f->accept >= maxsetvec) { /* guessing here! */
setvec = reallocarray(setvec, maxsetvec,
4 * sizeof(int));
tmpset = reallocarray(tmpset, maxsetvec,
4 * sizeof(int));
if (setvec == 0 || tmpset == 0)
overflo("out of space in cfoll()");
maxsetvec *= 4;
}
for (i = 0; i <= f->accept; i++)
setvec[i] = 0;
setcnt = 0;
follow(v); /* computes setvec and setcnt */
if ((p = (int *) calloc(setcnt+1, sizeof(int))) == NULL)
overflo("out of space building follow set");
f->re[info(v)].lfollow = p;
*p = setcnt;
for (i = f->accept; i >= 0; i--)
if (setvec[i] == 1)
*++p = i;
break;
UNARY
cfoll(f,left(v));
break;
case CAT:
case OR:
cfoll(f,left(v));
cfoll(f,right(v));
break;
default: /* can't happen */
FATAL("can't happen: unknown type %d in cfoll", type(v));
}
}
/**
* make automaton.
*/
void
cgotofn(const char *pattern) {
int c;
struct words *s;
s = smax = w;
nword: for(;;) {
c = *pattern++;
if (c==0)
return;
if (c == '\n') {
s->out = 1;
s = w;
} else {
loop: if (s->inp == c) {
s = s->nst;
continue;
}
if (s->inp == 0) goto enter;
if (s->link == 0) {
if (smax >= &w[MAXSIZ - 1])
overflo();
s->link = ++smax;
s = smax;
goto enter;
}
s = s->link;
goto loop;
}
}
enter:
do {
s->inp = c;
if (smax >= &w[MAXSIZ - 1])
overflo();
s->nst = ++smax;
s = smax;
} while ((c = *pattern++) != '\n' && c!=0);
smax->out = 1;
s = w;
if (c != 0)
goto nword;
}
int nematch(fa *f, char *p0) /* non-empty match, for sub */
{
int s, ns;
uschar *p = (uschar *) p0;
uschar *q;
int i, k;
s = f->reset ? makeinit(f,1) : f->initstat;
patlen = -1;
while (*p) {
q = p;
do {
if (f->out[s]) /* final state */
patlen = q-p;
if ((ns = f->gototab[s][*q]) != 0)
s = ns;
else
s = cgoto(f, s, *q);
if (s == 1) /* no transition */
if (patlen > 0) {
patbeg = (char *) p;
return(1);
} else
goto nnextin; /* no nonempty match */
} while (*q++ != 0);
if (f->out[s])
patlen = q-p-1; /* don't count $ */
if (patlen > 0 ) {
patbeg = (char *) p;
return(1);
}
nnextin:
s = 2;
if (f->reset) {
for (i = 2; i <= f->curstat; i++)
xfree(f->posns[i]);
k = *f->posns[0];
if ((f->posns[2] = (int *) calloc(1, (k+1)*sizeof(int))) == NULL)
overflo("out of state space");
for (i = 0; i <= k; i++)
(f->posns[2])[i] = (f->posns[0])[i];
f->initstat = f->curstat = 2;
f->out[2] = f->out[0];
for (i = 0; i < NCHARS; i++)
f->gototab[2][i] = 0;
}
p++;
}
return (0);
}
int first(Node *p) /* collects initially active leaves of p into setvec */
/* returns 0 if p matches empty string */
{
int b, lp;
switch (type(p)) {
ELEAF
LEAF
lp = info(p); /* look for high-water mark of subscripts */
while (setcnt >= maxsetvec || lp >= maxsetvec) { /* guessing here! */
setvec = reallocarray(setvec, maxsetvec,
4 * sizeof(int));
tmpset = reallocarray(tmpset, maxsetvec,
4 * sizeof(int));
if (setvec == 0 || tmpset == 0)
overflo("out of space in first()");
maxsetvec *= 4;
}
if (type(p) == EMPTYRE) {
setvec[lp] = 0;
return(0);
}
if (setvec[lp] != 1) {
setvec[lp] = 1;
setcnt++;
}
if (type(p) == CCL && (*(char *) right(p)) == '\0')
return(0); /* empty CCL */
else return(1);
case PLUS:
if (first(left(p)) == 0) return(0);
return(1);
case STAR:
case QUEST:
first(left(p));
return(0);
case CAT:
if (first(left(p)) == 0 && first(right(p)) == 0) return(0);
return(1);
case OR:
b = first(right(p));
if (first(left(p)) == 0 || b == 0) return(0);
return(1);
}
FATAL("can't happen: unknown type %d in first", type(p)); /* can't happen */
return(-1);
}
fa *makedfa(const char *s, int anchor) /* returns dfa for reg expr s */
{
int i, use, nuse;
fa *pfa;
static int now = 1;
if (setvec == 0) { /* first time through any RE */
maxsetvec = MAXLIN;
setvec = (int *) malloc(maxsetvec * sizeof(int));
tmpset = (int *) malloc(maxsetvec * sizeof(int));
if (setvec == 0 || tmpset == 0)
overflo("out of space initializing makedfa");
}
if (compile_time) /* a constant for sure */
return mkdfa(s, anchor);
for (i = 0; i < nfatab; i++) /* is it there already? */
if (fatab[i]->anchor == anchor
&& strcmp((const char *) fatab[i]->restr, s) == 0) {
fatab[i]->use = now++;
return fatab[i];
}
pfa = mkdfa(s, anchor);
if (nfatab < NFA) { /* room for another */
fatab[nfatab] = pfa;
fatab[nfatab]->use = now++;
nfatab++;
return pfa;
}
use = fatab[0]->use; /* replace least-recently used */
nuse = 0;
for (i = 1; i < nfatab; i++)
if (fatab[i]->use < use) {
use = fatab[i]->use;
nuse = i;
}
freefa(fatab[nuse]);
fatab[nuse] = pfa;
pfa->use = now++;
return pfa;
}
int cgoto(fa *f, int s, int c)
{
int i, j, k;
int *p, *q;
assert(c == HAT || c < NCHARS);
while (f->accept >= maxsetvec) { /* guessing here! */
maxsetvec *= 4;
setvec = (int *) realloc(setvec, maxsetvec * sizeof(int));
tmpset = (int *) realloc(tmpset, maxsetvec * sizeof(int));
if (setvec == 0 || tmpset == 0)
overflo("out of space in cgoto()");
}
for (i = 0; i <= f->accept; i++)
setvec[i] = 0;
setcnt = 0;
/* compute positions of gototab[s,c] into setvec */
p = f->posns[s];
for (i = 1; i <= *p; i++) {
if ((k = f->re[p[i]].ltype) != FINAL) {
if ((k == CHAR && c == ptoi(f->re[p[i]].lval.np))
|| (k == DOT && c != 0 && c != HAT)
|| (k == ALL && c != 0)
|| (k == EMPTYRE && c != 0)
|| (k == CCL && member(c, (char *) f->re[p[i]].lval.up))
|| (k == NCCL && !member(c, (char *) f->re[p[i]].lval.up) && c != 0 && c != HAT)) {
q = f->re[p[i]].lfollow;
for (j = 1; j <= *q; j++) {
if (q[j] >= maxsetvec) {
maxsetvec *= 4;
setvec = (int *) realloc(setvec, maxsetvec * sizeof(int));
tmpset = (int *) realloc(setvec, maxsetvec * sizeof(int));
if (setvec == 0 || tmpset == 0)
overflo("cgoto overflow");
}
if (setvec[q[j]] == 0) {
setcnt++;
setvec[q[j]] = 1;
}
}
}
}
}
/* determine if setvec is a previous state */
tmpset[0] = setcnt;
j = 1;
for (i = f->accept; i >= 0; i--)
if (setvec[i]) {
tmpset[j++] = i;
}
/* tmpset == previous state? */
for (i = 1; i <= f->curstat; i++) {
p = f->posns[i];
if ((k = tmpset[0]) != p[0])
goto different;
for (j = 1; j <= k; j++)
if (tmpset[j] != p[j])
goto different;
/* setvec is state i */
f->gototab[s][c] = i;
return i;
different:
;
}
/* add tmpset to current set of states */
if (f->curstat >= NSTATES-1) {
f->curstat = 2;
f->reset = 1;
for (i = 2; i < NSTATES; i++)
xfree(f->posns[i]);
} else
++(f->curstat);
for (i = 0; i < NCHARS; i++)
f->gototab[f->curstat][i] = 0;
xfree(f->posns[f->curstat]);
if ((p = (int *) calloc(1, (setcnt+1)*sizeof(int))) == NULL)
overflo("out of space in cgoto");
f->posns[f->curstat] = p;
f->gototab[s][c] = f->curstat;
for (i = 0; i <= setcnt; i++)
p[i] = tmpset[i];
if (setvec[f->accept])
f->out[f->curstat] = 1;
else
f->out[f->curstat] = 0;
return f->curstat;
}
