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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.
 *
 * $PostgreSQL: pgsql/src/backend/regex/regc_cvec.c,v 1.6 2008/02/14 17:33:37 tgl Exp $
 *
 */

/*
 * Notes:
 * Only (selected) functions in _this_ file should treat chr* as non-constant.
 */

/*
 * newcvec - allocate a new cvec
 */
static struct cvec *
newcvec(int nchrs,                        /* to hold this many chrs... */
            int nranges)                  /* ... and this many ranges */
{
      size_t            nc = (size_t) nchrs + (size_t) nranges * 2;
      size_t            n = sizeof(struct cvec) + nc * sizeof(chr);
      struct cvec *cv = (struct cvec *) MALLOC(n);

      if (cv == NULL)
            return NULL;
      cv->chrspace = nchrs;
      cv->chrs = (chr *) (((char *) cv) + sizeof(struct cvec));
      cv->ranges = cv->chrs + nchrs;
      cv->rangespace = nranges;
      return clearcvec(cv);
}

/*
 * clearcvec - clear a possibly-new cvec
 * Returns pointer as convenience.
 */
static struct cvec *
clearcvec(struct cvec * cv)
{
      assert(cv != NULL);
      cv->nchrs = 0;
      cv->nranges = 0;
      return cv;
}

/*
 * addchr - add a chr to a cvec
 */
static void
addchr(struct cvec * cv,            /* character vector */
         chr c)                           /* character to add */
{
      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++;
}

/*
 * 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 */
{
      if (v->cv != NULL && nchrs <= v->cv->chrspace &&
            nranges <= v->cv->rangespace)
            return clearcvec(v->cv);

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

      return v->cv;
}

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

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