/*
 * 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.
 */

/*
 * Notes:
 * Only (selected) functions in _this_ file should treat chr* as non-constant.
 */

/*
 - newcvec - allocate a new cvec
 ^ static struct cvec *newcvec(int, int);
 */
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 *);
 */
static struct cvec *
clearcvec(
    struct cvec *cv)		/* character vector */
{
    assert(cv != NULL);
    cv->nchrs = 0;
    cv->nranges = 0;
    return cv;
}

/*
 - addchr - add a chr to a cvec
 ^ static VOID addchr(struct cvec *, pchr);
 */
static void
addchr(
    struct cvec *cv,		/* character vector */
    pchr c)			/* character to add */
{
    cv->chrs[cv->nchrs++] = (chr)c;
}

/*
 - addrange - add a range to a cvec
 ^ static VOID addrange(struct cvec *, pchr, pchr);
 */
static void
addrange(
    struct cvec *cv,		/* character vector */
    pchr from,			/* first character of range */
    pchr 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 *, int, int);
 */
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 *);
 */
static void
freecvec(
    struct cvec *cv)		/* character vector */
{
    FREE(cv);
}

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */