postgres/src/backend/regex/regc_cvec.c

/*
 * Utility functions for handling cvecs
 * This file is #included by regcomp.c.
 *
 * Copyright (c) 1998, 1999 Henry Spencer.  All rights reserved.
 * 
 * Development of this software was funded, in part, by Cray Research Inc.,
 * UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics
 * Corporation, none of whom are responsible for the results.  The author
 * thanks all of them. 
 * 
 * Redistribution and use in source and binary forms -- with or without
 * modification -- are permitted for any purpose, provided that
 * redistributions in source form retain this entire copyright notice and
 * indicate the origin and nature of any modifications.
 * 
 * I'd appreciate being given credit for this package in the documentation
 * of software which uses it, but that is not a requirement.
 * 
 * THIS SOFTWARE IS PROVIDED ``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
 * HENRY SPENCER 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.
 *
 * $Header: /cvsroot/pgsql/src/backend/regex/regc_cvec.c,v 1.1 2003/02/05 17:41:32 tgl Exp $
 *
 */

/*
 * newcvec - allocate a new cvec
 */
static struct cvec *
newcvec(int nchrs,				/* to hold this many chrs... */
		int nranges,			/* ... and this many ranges... */
		int nmcces)				/* ... and this many MCCEs */
{
    size_t n;
    size_t nc;
    struct cvec *cv;

    nc = (size_t)nchrs + (size_t)nmcces*(MAXMCCE+1) + (size_t)nranges*2;
    n = sizeof(struct cvec) + (size_t)(nmcces-1)*sizeof(chr *)
	    + nc*sizeof(chr);
    cv = (struct cvec *)MALLOC(n);
    if (cv == NULL) {
	return NULL;
    }
    cv->chrspace = nchrs;
    cv->chrs = (chr *)&cv->mcces[nmcces];	/* chrs just after MCCE ptrs */
    cv->mccespace = nmcces;
    cv->ranges = cv->chrs + nchrs + nmcces*(MAXMCCE+1);
    cv->rangespace = nranges;
    return clearcvec(cv);
}

/*
 * clearcvec - clear a possibly-new cvec
 * Returns pointer as convenience.
 */
static struct cvec *
clearcvec(struct cvec *cv)
{
    int i;

    assert(cv != NULL);
    cv->nchrs = 0;
    assert(cv->chrs == (chr *)&cv->mcces[cv->mccespace]);
    cv->nmcces = 0;
    cv->nmccechrs = 0;
    cv->nranges = 0;
    for (i = 0; i < cv->mccespace; i++) {
	cv->mcces[i] = NULL;
    }

    return cv;
}

/*
 * addchr - add a chr to a cvec
 */
static void
addchr(struct cvec *cv,			/* character vector */
	   chr c)				/* character to add */
{
    assert(cv->nchrs < cv->chrspace - cv->nmccechrs);
    cv->chrs[cv->nchrs++] = (chr)c;
}

/*
 * addrange - add a range to a cvec
 */
static void
addrange(struct cvec *cv,			/* character vector */
		 chr from,				/* first character of range */
		 chr to)				/* last character of range */
{
    assert(cv->nranges < cv->rangespace);
    cv->ranges[cv->nranges*2] = (chr)from;
    cv->ranges[cv->nranges*2 + 1] = (chr)to;
    cv->nranges++;
}

/*
 * addmcce - add an MCCE to a cvec
 */
static void
addmcce(struct cvec *cv,			/* character vector */
		chr *startp,			/* beginning of text */
		chr *endp)				/* just past end of text */
{
    int len;
    int i;
    chr *s;
    chr *d;

    if (startp == NULL && endp == NULL) {
	return;
    }
    len = endp - startp;
    assert(len > 0);
    assert(cv->nchrs + len < cv->chrspace - cv->nmccechrs);
    assert(cv->nmcces < cv->mccespace);
    d = &cv->chrs[cv->chrspace - cv->nmccechrs - len - 1];
    cv->mcces[cv->nmcces++] = d;
    for (s = startp, i = len; i > 0; s++, i--) {
	*d++ = *s;
    }
    *d++ = 0;				/* endmarker */
    assert(d == &cv->chrs[cv->chrspace - cv->nmccechrs]);
    cv->nmccechrs += len + 1;
}

/*
 * haschr - does a cvec contain this chr?
 */
static int				/* predicate */
haschr(struct cvec *cv,			/* character vector */
	   chr c)				/* character to test for */
{
    int i;
    chr *p;

    for (p = cv->chrs, i = cv->nchrs; i > 0; p++, i--) {
	if (*p == c) {
	    return 1;
	}
    }
    for (p = cv->ranges, i = cv->nranges; i > 0; p += 2, i--) {
	if ((*p <= c) && (c <= *(p+1))) {
	    return 1;
	}
    }
    return 0;
}

/*
 * getcvec - get a cvec, remembering it as v->cv
 */
static struct cvec *
getcvec(struct vars *v,			/* context */
		int nchrs,				/* to hold this many chrs... */
		int nranges,			/* ... and this many ranges... */
		int nmcces)				/* ... and this many MCCEs */
{
    if (v->cv != NULL && nchrs <= v->cv->chrspace &&
	    nranges <= v->cv->rangespace && nmcces <= v->cv->mccespace) {
	return clearcvec(v->cv);
    }

    if (v->cv != NULL) {
	freecvec(v->cv);
    }
    v->cv = newcvec(nchrs, nranges, nmcces);
    if (v->cv == NULL) {
	ERR(REG_ESPACE);
    }

    return v->cv;
}

/*
 * freecvec - free a cvec
 */
static void
freecvec(struct cvec *cv)
{
    FREE(cv);
}