Replace regular expression package with Henry Spencer's latest version

(extracted from Tcl 8.4.1 release, as Henry still hasn't got round to
making it a separate library).  This solves a performance problem for
multibyte, as well as upgrading our regexp support to match recent Tcl
and nearly match recent Perl.

src/backend/regex/regc_cvec.c

@@ -0,0 +1,194 @@
+/*
+ * 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);
+}