ack/util/LLgen/lib/rec

/* 
 * Some grammar independent code.
 * This file is copied into Lpars.c.
 */

# ifndef lint
static char *rcsid = "$Header$";
# endif

unsigned int	LLtcnt[LL_NTERMINALS];
unsigned int	LLscnt[LL_NSETS];
int		LLcsymb, LLsymb;
static int	LLlevel;

/* In this file are defined: */
extern		LLread();
extern int	LLskip();
extern int	LLnext();
#ifndef LL_FASTER
extern		LLscan();
#endif
extern		LLerror();
# ifndef LLNOFIRSTS
extern int	LLfirst();
# endif
extern		LLnewlevel();
extern		LLoldlevel();

#ifdef LL_USERHOOK
static		LLdoskip();
#endif

#ifndef LL_FASTER
LLscan(t) {
	/*
	 * Check if the next symbol is equal to the parameter
	 */
	if ((LLsymb = LL_LEXI()) == t) {
		return;
	}
	/*
	 * If we come here, an error has been detected
	 */
	LLerror(t);
}
#endif

LLread() {
	for (;;) {
		if ((LLcsymb = LLindex[(LLsymb = LL_LEXI())]) >= 0) return;
		LLmessage(0);
	}
	/* NOTREACHED */
}

LLerror(t) {
	register int i;

	if (t == EOFILE && LLsymb <= 0) return;
#ifdef LL_NEWMESS
	if (t == EOFILE) {
#ifdef LL_USERHOOK
		static int lst[] = { EOFILE, 0 };
		LLuserhook(EOFILE, lst);
#endif LL_USERHOOK
		if (LLsymb != EOFILE && LLsymb > 0) {
			LLmessage(-1);
			while ((LLsymb = LL_LEXI()) > 0 && LLsymb != EOFILE) 
				/* nothing */ ;
		}
		return;
	}
#endif
	if ((LLcsymb = LLindex[LLsymb]) < 0) {
		LLmessage(0);
		LLread();
	}
	i = LLindex[t];
	LLtcnt[i]++;
#ifdef LL_USERHOOK
	if (LLdoskip(t)) /* nothing */;
#else
	if (LLskip()) /* nothing */;
#endif
	LLtcnt[i]--;
	if (LLsymb != t) LLmessage(t);
}

# ifndef LLNOFIRSTS
LLfirst(x, d) {
	register int i;

	return (i = LLindex[x]) >= 0 &&
		(LLsets[d + (i >> 3)] & (1 << (i & 07)));
}
# endif

LLnext(n) {
	/*	returns: 0 if the current symbol is'nt skipped, and it
			 is'nt a member of "n",
			 1 if we have a new symbol, but it is'nt a member,
			 2 if the current symbol is a member,
			 and 3 if we have a new symbol and it is a member.
		So, the low order bit indicates wether we have a new symbol,
		and the next bit indicates wether it is a member of "n".
	*/

	int retval = 0;

	if (LLskip()) retval = 1;
	if (n <= 0 && LLsets[(LLcsymb >> 3) - n] & (1 << (LLcsymb & 07))) {
		retval |= 2;
	}
	else if (n > 0 && LLcsymb == LLindex[n]) retval |= 2;
	return retval;
}

LLskip() {
	/*	returns 0 if the current symbol is'nt skipped, and
		1 if it is, t.i., we have a new symbol
	*/
#ifdef LL_USERHOOK
	return LLdoskip(0);
}

static int
LLuserhook(exp, list)
	int *list;
{
	int old = LLsymb;
	LL_USERHOOK(exp, list);
	LLread();
	return LLsymb != old;
}

static
LLmklist(list)
	register int *list;
{
	char Xset[LL_SSIZE];
	register char *p;
	register int i;

	for (p = &Xset[0]; p < &Xset[LL_SSIZE]; ) *p++ = 0;
	for (i = 0; i < LL_NTERMINALS; i++) {
		if (LLtcnt[i] != 0) Xset[i >> 3] |= (1 << (i & 07));
	}
	for (i = LL_NSETS - 1; i >= 0; i--) if (LLscnt[i] != 0) {
		register char *q = &LLsets[LL_SSIZE * i];

		p = &Xset[0];
		while (p < &Xset[LL_SSIZE]) *p++ |= *q++;
	}
	for (i = 0; i < LL_NTERMINALS; i++) {
		if (Xset[i >> 3] & (1 << (i & 07))) {
			*list++ = LLtok[i];
		}
	}
	*list = 0;
}

static
LLdoskip(exp) {
	int LLx;
	int list[LL_NTERMINALS+1];
#endif LL_USERHOOK
	register int i;
	int retval;
	int LLi, LLb;

	retval = 0;
#ifdef LL_USERHOOK
	LLmklist(list);
	LLx = LLuserhook(exp, list);
	if (LLx) retval = 1;
#endif LL_USERHOOK
	for (;;) {
		if (LLtcnt[LLcsymb] != 0) {
#ifdef LL_USERHOOK
			if (!exp || !LLx || LLcsymb == LLindex[exp])
#endif
			return retval;
		}
		LLi = LLcsymb >> 3;
		LLb = 1 << (LLcsymb & 07);
		for (i = LL_NSETS - 1; i >= 0; i--) {
			if (LLscnt[i] != 0) {
				if (LLsets[LL_SSIZE*i+LLi] & LLb) {
#ifdef LL_USERHOOK
					if (!exp || !LLx || LLcsymb == LLindex[exp])
#endif
					return retval;
				}
			}
		}
#ifdef LL_USERHOOK
		if (LLx) {
			LLx = LLuserhook(exp, list);
			continue;
		}
#endif LL_USERHOOK
		LLmessage(0);
		retval = 1;
		LLread();
	}
	/* NOTREACHED */
}

LLnewlevel(LLsinfo) unsigned int *LLsinfo; {
	register int i;

	if (LLlevel++) {
		LLsinfo[LL_NSETS+LL_NTERMINALS] = (unsigned) LLsymb;
		LLsinfo[LL_NSETS+LL_NTERMINALS+1] = (unsigned) LLcsymb;
		for (i = LL_NTERMINALS - 1; i >= 0; i--) {
			LLsinfo[i] = LLtcnt[i];
			LLtcnt[i] = 0;
		}
		for (i = LL_NSETS - 1; i >= 0; i--) {
			LLsinfo[LL_NTERMINALS+i] = LLscnt[i];
			LLscnt[i] = 0;
		}
	}
	LLtincr(0);
}

LLoldlevel(LLsinfo) unsigned int *LLsinfo; {
	register int i;

	LLtdecr(0);
# ifdef LL_DEBUG
	for (i = 0; i < LL_NTERMINALS; i++) LL_assert(LLtcnt[i] == 0);
	for (i = 0; i < LL_NSETS; i++) LL_assert(LLscnt[i] == 0);
# endif
	if (--LLlevel) {
		for (i = LL_NSETS - 1; i >= 0; i--) {
			LLscnt[i] = LLsinfo[LL_NTERMINALS+i];
		}
		for (i = LL_NTERMINALS - 1; i >= 0; i--) {
			LLtcnt[i] = LLsinfo[i];
		}
		LLsymb = (int) LLsinfo[LL_NSETS+LL_NTERMINALS];
		LLcsymb = (int) LLsinfo[LL_NSETS+LL_NTERMINALS+1];
	}
}