engine.c

关系型数据库 Postgresql 6.5.2

					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 0;
}

/*
 - fast - step through the string at top speed
 == static char *fast(struct match *m, char *start, \
 ==		char *stop, sopno startst, sopno stopst);
 */
static pg_wchar *				/* where tentative match ended, or NULL */
fast(m, start, stop, startst, stopst)
struct match *m;
pg_wchar   *start;
pg_wchar   *stop;
sopno		startst;
sopno		stopst;
{
	states		st = m->st;
	states		fresh = m->fresh;
	states		tmp = m->tmp;
	pg_wchar   *p = start;
	int			c = (start == m->beginp) ? OUT : *(start - 1);
	int			lastc;			/* previous c */
	int			flagch;
	int			i;
	pg_wchar   *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(struct match *m, char *start, \
 ==		char *stop, sopno startst, sopno stopst);
 */
static pg_wchar *				/* where it ended */
slow(m, start, stop, startst, stopst)
struct match *m;
pg_wchar   *start;
pg_wchar   *stop;
sopno		startst;
sopno		stopst;
{
	states		st = m->st;
	states		empty = m->empty;
	states		tmp = m->tmp;
	pg_wchar   *p = start;
	int			c = (start == m->beginp) ? OUT : *(start - 1);
	int			lastc;			/* previous c */
	int			flagch;
	int			i;
	pg_wchar   *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(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)
 */
static states
step(g, start, stop, bef, ch, aft)
struct re_guts *g;
sopno		start;				/* start state within strip */
sopno		stop;				/* state after stop state within strip */
states		bef;				/* states reachable before */
int			ch;					/* character or NONCHAR code */
states		aft;				/* states already known reachable after */
{
	cset	   *cs;
	sop			s;
	sopno		pc;
	onestate	here;			/* note, macros know this name */
	sopno		look;
	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 != (pg_wchar) OPND(s));
				if (ch == (pg_wchar) 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;
pg_wchar   *caption;
states		st;
int			ch;
FILE	   *d;
{
	struct re_guts *g = m->g;
	int			i;
	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, pg_wchar *title, pg_wchar *start, pg_wchar *stop, \
 ==												sopno startst, sopno stopst);
 == #endif
 */
static void
at(m, title, start, stop, startst, stopst)
struct match *m;
pg_wchar   *title;
pg_wchar   *start;
pg_wchar   *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 int
pg_isprint(int c)
{
#ifdef MULTIBYTE
	return (c >= 0 && c <= UCHAR_MAX && isprint(c));
#else
	return (isprint(c));
#endif
}

static pg_wchar *				/* -> representation */
pchar(ch)
int			ch;
{
	static pg_wchar pbuf[10];

	if (pg_isprint(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