regcomp.c

关系型数据库 Postgresql 6.5.2

/*-
 * Copyright (c) 1992, 1993, 1994 Henry Spencer.
 * Copyright (c) 1992, 1993, 1994
 *		The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Henry Spencer.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *	  notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *	  notice, this list of conditions and the following disclaimer in the
 *	  documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *	  must display the following acknowledgement:
 *		This product includes software developed by the University of
 *		California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *	  may be used to endorse or promote products derived from this software
 *	  without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.	IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *		@(#)regcomp.c	8.5 (Berkeley) 3/20/94
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)regcomp.c	8.5 (Berkeley) 3/20/94";

#endif	 /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <limits.h>
#include <stdlib.h>
#include <assert.h>

#include <regex/regex.h>
#include <regex/utils.h>
#include <regex/regex2.h>
#include <regex/cclass.h>
#include <regex/cname.h>

/*
 * parse structure, passed up and down to avoid global variables and
 * other clumsinesses
 */
struct parse
{
	pg_wchar   *next;			/* next character in RE */
	pg_wchar   *end;			/* end of string (-> NUL normally) */
	int			error;			/* has an error been seen? */
	sop		   *strip;			/* malloced strip */
	sopno		ssize;			/* malloced strip size (allocated) */
	sopno		slen;			/* malloced strip length (used) */
	int			ncsalloc;		/* number of csets allocated */
	struct re_guts *g;
#define  NPAREN  10				/* we need to remember () 1-9 for back
								 * refs */
	sopno		pbegin[NPAREN]; /* -> ( ([0] unused) */
	sopno		pend[NPAREN];	/* -> ) ([0] unused) */
};

/* ========= begin header generated by ./mkh ========= */
#ifdef __cplusplus
extern		"C"
{
#endif

/* === regcomp.c === */
	static void p_ere(struct parse * p, int stop);
	static void p_ere_exp(struct parse * p);
	static void p_str(struct parse * p);
	static void p_bre(struct parse * p, int end1, int end2);
	static int	p_simp_re(struct parse * p, int starordinary);
	static int	p_count(struct parse * p);
	static void p_bracket(struct parse * p);
	static void p_b_term(struct parse * p, cset *cs);
	static void p_b_cclass(struct parse * p, cset *cs);
	static void p_b_eclass(struct parse * p, cset *cs);
	static pg_wchar p_b_symbol(struct parse * p);
	static char p_b_coll_elem(struct parse * p, int endc);
#ifdef MULTIBYTE
	static unsigned char othercase(int ch);
#else
	static char othercase(int ch);
#endif
	static void bothcases(struct parse * p, int ch);
	static void ordinary(struct parse * p, int ch);
	static void nonnewline(struct parse * p);
	static void repeat(struct parse * p, sopno start, int from, int to);
	static int	seterr(struct parse * p, int e);
	static cset *allocset(struct parse * p);
	static void freeset(struct parse * p, cset *cs);
	static int	freezeset(struct parse * p, cset *cs);
	static int	firstch(struct parse * p, cset *cs);
	static int	nch(struct parse * p, cset *cs);
	static void mcadd(struct parse * p, cset *cs, char *cp);
	static void mcinvert(struct parse * p, cset *cs);
	static void mccase(struct parse * p, cset *cs);
	static int	isinsets(struct re_guts * g, int c);
	static int	samesets(struct re_guts * g, int c1, int c2);
	static void categorize(struct parse * p, struct re_guts * g);
	static sopno dupl(struct parse * p, sopno start, sopno finish);
	static void doemit(struct parse * p, sop op, size_t opnd);
	static void doinsert(struct parse * p, sop op, size_t opnd, sopno pos);
	static void dofwd(struct parse * p, sopno pos, sop value);
	static void enlarge(struct parse * p, sopno size);
	static void stripsnug(struct parse * p, struct re_guts * g);
	static void findmust(struct parse * p, struct re_guts * g);
	static sopno pluscount(struct parse * p, struct re_guts * g);
	static int	pg_isdigit(int c);
	static int	pg_isalpha(int c);
	static int	pg_isupper(int c);
	static int	pg_islower(int c);

#ifdef __cplusplus
}

#endif
/* ========= end header generated by ./mkh ========= */

static pg_wchar nuls[10];		/* place to point scanner in event of
								 * error */

/*
 * macros for use with parse structure
 * BEWARE:	these know that the parse structure is named `p' !!!
 */
#define PEEK()	(*p->next)
#define PEEK2() (*(p->next+1))
#define MORE()	(p->next < p->end)
#define MORE2() (p->next+1 < p->end)
#define SEE(c)	(MORE() && PEEK() == (c))
#define SEETWO(a, b)	(MORE() && MORE2() && PEEK() == (a) && PEEK2() == (b))
#define EAT(c)	((SEE(c)) ? (NEXT(), 1) : 0)
#define EATTWO(a, b)	((SEETWO(a, b)) ? (NEXT2(), 1) : 0)
#define NEXT()	(p->next++)
#define NEXT2() (p->next += 2)
#define NEXTn(n)		(p->next += (n))
#define GETNEXT()		(*p->next++)
#define SETERROR(e)		seterr(p, (e))
#define REQUIRE(co, e)	if (!(co)) SETERROR(e)
#define MUSTSEE(c, e)	REQUIRE(MORE() && PEEK() == (c), e)
#define MUSTEAT(c, e)	REQUIRE(MORE() && GETNEXT() == (c), e)
#define MUSTNOTSEE(c, e)		REQUIRE(!MORE() || PEEK() != (c), e)
#define EMIT(op, sopnd) doemit(p, (sop)(op), (size_t)(sopnd))
#define INSERT(op, pos) doinsert(p, (sop)(op), HERE()-(pos)+1, pos)
#define AHEAD(pos)				dofwd(p, pos, HERE()-(pos))
#define ASTERN(sop, pos)		EMIT(sop, HERE()-pos)
#define HERE()			(p->slen)
#define THERE()			(p->slen - 1)
#define THERETHERE()	(p->slen - 2)
#define DROP(n) (p->slen -= (n))

#ifndef NDEBUG
static int	never = 0;			/* for use in asserts; shuts lint up */

#else
#define never	0				/* some <assert.h>s have bugs too */
#endif

/*
 - regcomp - interface for parser and compilation
 = extern int regcomp(regex_t *, const char *, int);
 = #define		REG_BASIC		0000
 = #define		REG_EXTENDED	0001
 = #define		REG_ICASE		0002
 = #define		REG_NOSUB		0004
 = #define		REG_NEWLINE		0010
 = #define		REG_NOSPEC		0020
 = #define		REG_PEND		0040
 = #define		REG_DUMP		0200
 */
int								/* 0 success, otherwise REG_something */
pg95_regcomp(preg, pattern, cflags)
regex_t    *preg;
const char *pattern;
int			cflags;
{
	struct parse pa;
	struct re_guts *g;
	struct parse *p = &pa;
	int			i;
	size_t		len;

#ifdef MULTIBYTE
	pg_wchar   *wcp;

#endif

#ifdef REDEBUG
#define  GOODFLAGS(f)	 (f)
#else
#define  GOODFLAGS(f)	 ((f)&~REG_DUMP)
#endif

	cflags = GOODFLAGS(cflags);
	if ((cflags & REG_EXTENDED) && (cflags & REG_NOSPEC))
		return REG_INVARG;

	if (cflags & REG_PEND)
	{
#ifdef MULTIBYTE
		wcp = preg->patsave;
		if (preg->re_endp < wcp)
			return REG_INVARG;
		len = preg->re_endp - wcp;
#else
		if (preg->re_endp < pattern)
			return REG_INVARG;
		len = preg->re_endp - pattern;
#endif
	}
	else
	{
#ifdef MULTIBYTE
		wcp = (pg_wchar *) malloc((strlen(pattern) + 1) * sizeof(pg_wchar));
		if (wcp == NULL)
			return REG_ESPACE;
		preg->patsave = wcp;
		(void) pg_mb2wchar((unsigned char *) pattern, wcp);
		len = pg_wchar_strlen(wcp);
#else

		len = strlen((char *) pattern);
#endif
	}

	/* do the mallocs early so failure handling is easy */
	g = (struct re_guts *) malloc(sizeof(struct re_guts) +
								  (NC - 1) * sizeof(cat_t));
	if (g == NULL)
		return REG_ESPACE;
	p->ssize = len / (size_t) 2 *(size_t) 3 + (size_t) 1;		/* ugh */

	p->strip = (sop *) malloc(p->ssize * sizeof(sop));
	p->slen = 0;
	if (p->strip == NULL)
	{
		free((char *) g);
		return REG_ESPACE;
	}

	/* set things up */
	p->g = g;
#ifdef MULTIBYTE
	p->next = wcp;
#else
	p->next = (pg_wchar *) pattern;		/* convenience; we do not modify
										 * it */
#endif
	p->end = p->next + len;
	p->error = 0;
	p->ncsalloc = 0;
	for (i = 0; i < NPAREN; i++)
	{
		p->pbegin[i] = 0;
		p->pend[i] = 0;
	}
	g->csetsize = NC;
	g->sets = NULL;
	g->setbits = NULL;
	g->ncsets = 0;
	g->cflags = cflags;
	g->iflags = 0;
	g->nbol = 0;
	g->neol = 0;
	g->must = NULL;
	g->mlen = 0;
	g->nsub = 0;
	g->ncategories = 1;			/* category 0 is "everything else" */
	g->categories = &g->catspace[-(CHAR_MIN)];
	memset((char *) g->catspace, 0, NC * sizeof(cat_t));
	g->backrefs = 0;

	/* do it */
	EMIT(OEND, 0);
	g->firststate = THERE();
	if (cflags & REG_EXTENDED)
		p_ere(p, OUT);
	else if (cflags & REG_NOSPEC)
		p_str(p);
	else
		p_bre(p, OUT, OUT);
	EMIT(OEND, 0);
	g->laststate = THERE();

	/* tidy up loose ends and fill things in */
	categorize(p, g);
	stripsnug(p, g);
	findmust(p, g);
	g->nplus = pluscount(p, g);
	g->magic = MAGIC2;
	preg->re_nsub = g->nsub;
	preg->re_g = g;
	preg->re_magic = MAGIC1;
#ifndef REDEBUG
	/* not debugging, so can't rely on the assert() in regexec() */
	if (g->iflags & BAD)
		SETERROR(REG_ASSERT);
#endif

	/* win or lose, we're done */
	if (p->error != 0)			/* lose */
		pg95_regfree(preg);
	return p->error;
}

/*
 - p_ere - ERE parser top level, concatenation and alternation
 == static void p_ere(struct parse *p, int stop);
 */
static void
p_ere(p, stop)
struct parse *p;
int			stop;				/* character this ERE should end at */
{
	char		c;
	sopno		prevback = 0;
	sopno		prevfwd = 0;
	sopno		conc;
	int			first = 1;		/* is this the first alternative? */

	for (;;)
	{
		/* do a bunch of concatenated expressions */
		conc = HERE();
		while (MORE() && (c = PEEK()) != '|' && c != stop)
			p_ere_exp(p);
		REQUIRE(HERE() != conc, REG_EMPTY);		/* require nonempty */

		if (!EAT('|'))
			break;				/* NOTE BREAK OUT */

		if (first)
		{
			INSERT(OCH_, conc); /* offset is wrong */
			prevfwd = conc;
			prevback = conc;
			first = 0;
		}
		ASTERN(OOR1, prevback);
		prevback = THERE();
		AHEAD(prevfwd);			/* fix previous offset */
		prevfwd = HERE();
		EMIT(OOR2, 0);			/* offset is very wrong */
	}

	if (!first)
	{							/* tail-end fixups */
		AHEAD(prevfwd);
		ASTERN(O_CH, prevback);
	}

	assert(!MORE() || SEE(stop));
}

/*
 - p_ere_exp - parse one subERE, an atom possibly followed by a repetition op
 == static void p_ere_exp(struct parse *p);
 */
static void
p_ere_exp(p)
struct parse *p;
{
	pg_wchar	c;
	sopno		pos;
	int			count;
	int			count2;
	sopno		subno;
	int			wascaret = 0;

	assert(MORE());				/* caller should have ensured this */
	c = GETNEXT();

	pos = HERE();
	switch (c)
	{
		case '(':
			REQUIRE(MORE(), REG_EPAREN);
			p->g->nsub++;
			subno = p->g->nsub;
			if (subno < NPAREN)
				p->pbegin[subno] = HERE();
			EMIT(OLPAREN, subno);
			if (!SEE(')'))
				p_ere(p, ')');
			if (subno < NPAREN)
			{
				p->pend[subno] = HERE();
				assert(p->pend[subno] != 0);
			}
			EMIT(ORPAREN, subno);
			MUSTEAT(')', REG_EPAREN);
			break;
#ifndef POSIX_MISTAKE
		case ')':				/* happens only if no current unmatched ( */

			/*
			 * You may ask, why the ifndef?  Because I didn't notice this
			 * until slightly too late for 1003.2, and none of the other
			 * 1003.2 regular-expression reviewers noticed it at all.  So
			 * an unmatched ) is legal POSIX, at least until we can get it
			 * fixed.
			 */
			SETERROR(REG_EPAREN);
			break;
#endif
		case '^':
			EMIT(OBOL, 0);
			p->g->iflags |= USEBOL;
			p->g->nbol++;
			wascaret = 1;
			break;
		case '$':
			EMIT(OEOL, 0);
			p->g->iflags |= USEEOL;
			p->g->neol++;
			break;
		case '|':
			SETERROR(REG_EMPTY);
			break;
		case '*':
		case '+':
		case '?':
			SETERROR(REG_BADRPT);
			break;
		case '.':
			if (p->g->cflags & REG_NEWLINE)
				nonnewline(p);
			else
				EMIT(OANY, 0);
			break;
		case '[':
			p_bracket(p);
			break;
		case '\\':
			REQUIRE(MORE(), REG_EESCAPE);
			c = GETNEXT();
			ordinary(p, c);
			break;
		case '{':				/* okay as ordinary except if digit
								 * follows */
			REQUIRE(!MORE() || !pg_isdigit(PEEK()), REG_BADRPT);
			/* FALLTHROUGH */
		default:
			ordinary(p, c);
			break;
	}

	if (!MORE())
		return;
	c = PEEK();
	/* we call { a repetition if followed by a digit */
	if (!(c == '*' || c == '+' || c == '?' ||
		  (c == '{' && MORE2() && pg_isdigit(PEEK2()))))
		return;					/* no repetition, we're done */
	NEXT();

	REQUIRE(!wascaret, REG_BADRPT);
	switch (c)
	{
		case '*':				/* implemented as +? */
			/* this case does not require the (y|) trick, noKLUDGE */
			INSERT(OPLUS_, pos);
			ASTERN(O_PLUS, pos);
			INSERT(OQUEST_, pos);
			ASTERN(O_QUEST, pos);
			break;
		case '+':
			INSERT(OPLUS_, pos);
			ASTERN(O_PLUS, pos);
			break;
		case '?':
			/* KLUDGE: emit y? as (y|) until subtle bug gets fixed */
			INSERT(OCH_, pos);	/* offset slightly wrong */
			ASTERN(OOR1, pos);	/* this one's right */
			AHEAD(pos);			/* fix the OCH_ */
			EMIT(OOR2, 0);		/* offset very wrong... */
			AHEAD(THERE());		/* ...so fix it */
			ASTERN(O_CH, THERETHERE());
			break;
		case '{':
			count = p_count(p);
			if (EAT(','))
			{
				if (pg_isdigit(PEEK()))
				{
					count2 = p_count(p);
					REQUIRE(count <= count2, REG_BADBR);
				}
				else
/* single number with comma */
					count2 = INFINITY;
			}
			else
/* just a single number */
				count2 = count;
			repeat(p, pos, count, count2);
			if (!EAT('}'))
			{					/* error heuristics */
				while (MORE() && PEEK() != '}')
					NEXT();
				REQUIRE(MORE(), REG_EBRACE);
				SETERROR(REG_BADBR);
			}
			break;
	}

	if (!MORE())
		return;
	c = PEEK();
	if (!(c == '*' || c == '+' || c == '?' ||
		  (c == '{' && MORE2() && pg_isdigit(PEEK2()))))
		return;
	SETERROR(REG_BADRPT);
}

/*
 - p_str - string (no metacharacters) "parser"
 == static void p_str(struct parse *p);
 */
static void
p_str(p)
struct parse *p;
{
	REQUIRE(MORE(), REG_EMPTY);
	while (MORE())
		ordinary(p, GETNEXT());
}

/*
 - p_bre - BRE parser top level, anchoring and concatenation
 == static void p_bre(struct parse *p, int end1, \
 ==		int end2);
 * Giving end1 as OUT essentially eliminates the end1/end2 check.
 *
 * This implementation is a bit of a kludge, in that a trailing $ is first
 * taken as an ordinary character and then revised to be an anchor.  The
 * only undesirable side effect is that '$' gets included as a character
 * category in such cases.	This is fairly harmless; not worth fixing.
 * The amount of lookahead needed to avoid this kludge is excessive.
 */
static void
p_bre(p, end1, end2)
struct parse *p;
int			end1;				/* first terminating character */
int			end2;				/* second terminating character */
{
	sopno		start = HERE();
	int			first = 1;		/* first subexpression? */
	int			wasdollar = 0;

	if (EAT('^'))
	{
		EMIT(OBOL, 0);
		p->g->iflags |= USEBOL;
		p->g->nbol++;
	}
	while (MORE() && !SEETWO(end1, end2))
	{
		wasdollar = p_simp_re(p, first);
		first = 0;
	}
	if (wasdollar)
	{							/* oops, that was a trailing anchor */
		DROP(1);
		EMIT(OEOL, 0);
		p->g->iflags |= USEEOL;
		p->g->neol++;
	}

	REQUIRE(HERE() != start, REG_EMPTY);		/* require nonempty */
}

/*
 - p_simp_re - parse a simple RE, an atom possibly followed by a repetition
 == static int p_simp_re(struct parse *p, int starordinary);
 */
static int						/* was the simple RE an unbackslashed $? */
p_simp_re(p, starordinary)
struct parse *p;
int			starordinary;		/* is a leading * an ordinary character? */
{
	int			c;
	int			count;
	int			count2;
	sopno		pos;
	int			i;
	sopno		subno;

#define  BACKSL  (1<<24)

	pos = HERE();				/* repetion op, if any, covers from here */

	assert(MORE());				/* caller should have ensured this */
	c = GETNEXT();
	if (c == '\\')
	{
		REQUIRE(MORE(), REG_EESCAPE);
#ifdef MULTIBYTE
		c = BACKSL | (pg_wchar) GETNEXT();
#else
		c = BACKSL | (unsigned char) GETNEXT();
#endif
	}
	switch (c)
	{
		case '.':
			if (p->g->cflags & REG_NEWLINE)
				nonnewline(p);
			else
				EMIT(OANY, 0);
			break;
		case '[':
			p_bracket(p);
			break;
		case BACKSL | '{':
			SETERROR(REG_BADRPT);
			break;
		case BACKSL | '(':
			p->g->nsub++;
			subno = p->g->nsub;
			if (subno < NPAREN)