Import sources from 2011-03-30 iso image

sys/src/cmd/grep/comp.c

@@ -0,0 +1,285 @@
+#include	"grep.h"
+
+/*
+ * incremental compiler.
+ * add the branch c to the
+ * state s.
+ */
+void
+increment(State *s, int c)
+{
+	int i;
+	State *t, **tt;
+	Re *re1, *re2;
+
+	nfollow = 0;
+	gen++;
+	matched = 0;
+	for(i=0; i<s->count; i++)
+		fol1(s->re[i], c);
+	qsort(follow, nfollow, sizeof(*follow), fcmp);
+	for(tt=&state0; t = *tt;) {
+		if(t->count > nfollow) {
+			tt = &t->linkleft;
+			goto cont;
+		}
+		if(t->count < nfollow) {
+			tt = &t->linkright;
+			goto cont;
+		}
+		for(i=0; i<nfollow; i++) {
+			re1 = t->re[i];
+			re2 = follow[i];
+			if(re1 > re2) {
+				tt = &t->linkleft;
+				goto cont;
+			}
+			if(re1 < re2) {
+				tt = &t->linkright;
+				goto cont;
+			}
+		}
+		if(!!matched && !t->match) {
+			tt = &t->linkleft;
+			goto cont;
+		}
+		if(!matched && !!t->match) {
+			tt = &t->linkright;
+			goto cont;
+		}
+		s->next[c] = t;
+		return;
+	cont:;
+	}
+
+	t = sal(nfollow);
+	*tt = t;
+	for(i=0; i<nfollow; i++) {
+		re1 = follow[i];
+		t->re[i] = re1;
+	}
+	s->next[c] = t;
+	t->match = matched;
+}
+
+int
+fcmp(void *va, void *vb)
+{
+	Re **aa, **bb;
+	Re *a, *b;
+
+	aa = va;
+	bb = vb;
+	a = *aa;
+	b = *bb;
+	if(a > b)
+		return 1;
+	if(a < b)
+		return -1;
+	return 0;
+}
+
+void
+fol1(Re *r, int c)
+{
+	Re *r1;
+
+loop:
+	if(r->gen == gen)
+		return;
+	if(nfollow >= maxfollow)
+		error("nfollow");
+	r->gen = gen;
+	switch(r->type) {
+	default:
+		error("fol1");
+
+	case Tcase:
+		if(c >= 0 && c < 256)
+		if(r1 = r->cases[c])
+			follow[nfollow++] = r1;
+		if(r = r->next)
+			goto loop;
+		break;
+
+	case Talt:
+	case Tor:
+		fol1(r->alt, c);
+		r = r->next;
+		goto loop;
+
+	case Tbegin:
+		if(c == '\n' || c == Cbegin)
+			follow[nfollow++] = r->next;
+		break;
+
+	case Tend:
+		if(c == '\n') {
+			if(r->next == 0) {
+				matched = 1;
+				break;
+			}
+			r = r->next;
+			goto loop;
+		}
+		break;
+
+	case Tclass:
+		if(c >= r->lo && c <= r->hi)
+			follow[nfollow++] = r->next;
+		break;
+	}
+}
+
+Rune	tab1[] =
+{
+	0x007f,
+	0x07ff,
+};
+Rune	tab2[] =
+{
+	0x003f,
+	0x0fff,
+};
+
+Re2
+rclass(Rune p0, Rune p1)
+{
+	char xc0[6], xc1[6];
+	int i, n, m;
+	Re2 x;
+
+	if(p0 > p1)
+		return re2char(0xff, 0xff);	// no match
+
+	/*
+	 * bust range into same length
+	 * character sequences
+	 */
+	for(i=0; i<nelem(tab1); i++) {
+		m = tab1[i];
+		if(p0 <= m && p1 > m)
+			return re2or(rclass(p0, m), rclass(m+1, p1));
+	}
+
+	/*
+	 * bust range into part of a single page
+	 * or into full pages
+	 */
+	for(i=0; i<nelem(tab2); i++) {
+		m = tab2[i];
+		if((p0 & ~m) != (p1 & ~m)) {
+			if((p0 & m) != 0)
+				return re2or(rclass(p0, p0|m), rclass((p0|m)+1, p1));
+			if((p1 & m) != m)
+				return re2or(rclass(p0, (p1&~m)-1), rclass(p1&~m, p1));
+		}
+	}
+
+	n = runetochar(xc0, &p0);
+	i = runetochar(xc1, &p1);
+	if(i != n)
+		error("length");
+
+	x = re2char(xc0[0], xc1[0]);
+	for(i=1; i<n; i++)
+		x = re2cat(x, re2char(xc0[i], xc1[i]));
+	return x;
+}
+
+int
+pcmp(void *va, void *vb)
+{
+	int n;
+	Rune *a, *b;
+
+	a = va;
+	b = vb;
+
+	n = a[0] - b[0];
+	if(n)
+		return n;
+	return a[1] - b[1];
+}
+
+/*
+ * convert character chass into
+ * run-pair ranges of matches.
+ * this is 10646/utf specific and
+ * needs to be changed for some
+ * other input character set.
+ * this is the key to a fast
+ * regular search of characters
+ * by looking at sequential bytes.
+ */
+Re2
+re2class(char *s)
+{
+	Rune pairs[200+2], *p, *q, ov;
+	int nc;
+	Re2 x;
+
+	nc = 0;
+	if(*s == '^') {
+		nc = 1;
+		s++;
+	}
+
+	p = pairs;
+	s += chartorune(p, s);
+	for(;;) {
+		if(*p == '\\')
+			s += chartorune(p, s);
+		if(*p == 0)
+			break;
+		p[1] = *p;
+		p += 2;
+		if(p >= pairs + nelem(pairs) - 2)
+			error("class too big");
+		s += chartorune(p, s);
+		if(*p != '-')
+			continue;
+		s += chartorune(p, s);
+		if(*p == '\\')
+			s += chartorune(p, s);
+		if(*p == 0)
+			break;
+		p[-1] = *p;
+		s += chartorune(p, s);
+	}
+	*p = 0;
+	qsort(pairs, (p-pairs)/2, 2*sizeof(*pairs), pcmp);
+
+	q = pairs;
+	for(p=pairs+2; *p; p+=2) {
+		if(p[0] > p[1])
+			continue;
+		if(p[0] > q[1] || p[1] < q[0]) {
+			q[2] = p[0];
+			q[3] = p[1];
+			q += 2;
+			continue;
+		}
+		if(p[0] < q[0])
+			q[0] = p[0];
+		if(p[1] > q[1])
+			q[1] = p[1];
+	}
+	q[2] = 0;
+
+	p = pairs;
+	if(nc) {
+		x = rclass(0, p[0]-1);
+		ov = p[1]+1;
+		for(p+=2; *p; p+=2) {
+			x = re2or(x, rclass(ov, p[0]-1));
+			ov = p[1]+1;
+		}
+		x = re2or(x, rclass(ov, 0xffff));
+	} else {
+		x = rclass(p[0], p[1]);
+		for(p+=2; *p; p+=2)
+			x = re2or(x, rclass(p[0], p[1]));
+	}
+	return x;
+}