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Make the m4 machine stack dynamically sized.

Fix strspace automatic extension.
The assumption that simply updating the current pointer works is false,
there are cases where previous entries on the stack would absorp vast
amounts of string space, and overload the non-updated entries.

To fix it, we use a shadow copy of the stack, which only records which
entries are pointers within strspace, so that a resize can adjust all
those pointers at once.

Reviewed by millert@

/*	$OpenBSD: misc.c,v 1.19 2000/07/02 01:17:00 espie Exp $	*/
/*	$NetBSD: misc.c,v 1.6 1995/09/28 05:37:41 tls Exp $	*/

/*
 * Copyright (c) 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Ozan Yigit at York University.
 *
 * 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.
 */

#ifndef lint
#if 0
static char sccsid[] = "@(#)misc.c	8.1 (Berkeley) 6/6/93";
#else
static char rcsid[] = "$OpenBSD: misc.c,v 1.19 2000/07/02 01:17:00 espie Exp $";
#endif
#endif /* not lint */

#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <err.h>
#include "mdef.h"
#include "stdd.h"
#include "extern.h"
#include "pathnames.h"


char *ep;		/* first free char in strspace */
static char *strspace;	/* string space for evaluation */
static char *endest;	/* end of string space	       */
static size_t strsize = STRSPMAX;
static size_t bufsize = BUFSIZE;

char *buf;			/* push-back buffer	       */
char *bufbase;			/* the base for current ilevel */
char *bbase[MAXINP];		/* the base for each ilevel    */
char *bp; 			/* first available character   */
static char *endpbb;			/* end of push-back buffer     */


static void enlarge_bufspace __P((void));
static void enlarge_strspace __P((void));
/*
 * find the index of second str in the first str.
 */
ptrdiff_t
indx(s1, s2)
	const char *s1;
	const char *s2;
{
	char *t;

	t = strstr(s1, s2);
	if (t == NULL)
		return (-1);
	else
		return (t - s1);
}
/*
 *  putback - push character back onto input
 */
void
putback(c)
	int c;
{
	if (c == EOF)
		return;
	if (bp >= endpbb)
		enlarge_bufspace();
	*bp++ = c;
}

/*
 *  pbstr - push string back onto input
 *          putback is replicated to improve
 *          performance.
 */
void
pbstr(s)
	const char *s;
{
	size_t n;

	n = strlen(s);
	while (endpbb - bp <= n)
		enlarge_bufspace();
	while (n > 0)
		*bp++ = s[--n];
}

/*
 *  pbnum - convert number to string, push back on input.
 */
void
pbnum(n)
	int n;
{
	int num;

	num = (n < 0) ? -n : n;
	do {
		putback(num % 10 + '0');
	}
	while ((num /= 10) > 0);

	if (n < 0)
		putback('-');
}

/*
 *  pbunsigned - convert unsigned long to string, push back on input.
 */
void
pbunsigned(n)
	unsigned long n;
{
	do {
		putback(n % 10 + '0');
	}
	while ((n /= 10) > 0);
}

void 
initspaces()
{
	int i;

	strspace = xalloc(strsize+1);
	ep = strspace;
	endest = strspace+strsize;
	buf = (char *)xalloc(bufsize);
	bufbase = buf;
	bp = buf;
	endpbb = buf + bufsize;
	for (i = 0; i < MAXINP; i++)
		bbase[i] = buf;
}

static void 
enlarge_strspace()
{
	char *newstrspace;
	int i;

	strsize *= 2;
	newstrspace = malloc(strsize + 1);
	if (!newstrspace)
		errx(1, "string space overflow");
	memcpy(newstrspace, strspace, strsize/2);
	for (i = 0; i <= sp; i++) 
		if (sstack[i])
			mstack[i].sstr = (mstack[i].sstr - strspace) 
			    + newstrspace;
	ep = (ep-strspace) + newstrspace;
	free(strspace);
	strspace = newstrspace;
	endest = strspace + strsize;
}

static void
enlarge_bufspace()
{
	char *newbuf;
	int i;

	bufsize *= 2;
	newbuf = realloc(buf, bufsize);
	if (!newbuf)
		errx(1, "too many characters pushed back");
	for (i = 0; i < MAXINP; i++)
		bbase[i] = (bbase[i]-buf)+newbuf;
	bp = (bp-buf)+newbuf;
	bufbase = (bufbase-buf)+newbuf;
	buf = newbuf;
	endpbb = buf+bufsize;
}

/*
 *  chrsave - put single char on string space
 */
void
chrsave(c)
	int c;
{
	if (ep >= endest) 
		enlarge_strspace();
	*ep++ = c;
}

/*
 * read in a diversion file, and dispose it.
 */
void
getdiv(n)
	int n;
{
	int c;

	if (active == outfile[n])
		errx(1, "undivert: diversion still active");
	rewind(outfile[n]);
	while ((c = getc(outfile[n])) != EOF)
		putc(c, active);
	(void) fclose(outfile[n]);
	outfile[n] = NULL;
}

void
onintr(signo)
	int signo;
{
	errx(1, "interrupted.");
}

/*
 * killdiv - get rid of the diversion files
 */
void
killdiv()
{
	int n;

	for (n = 0; n < MAXOUT; n++)
		if (outfile[n] != NULL) {
			(void) fclose(outfile[n]);
		}
}

void *
xalloc(n)
	size_t n;
{
	char *p = malloc(n);

	if (p == NULL)
		err(1, "malloc");
	return p;
}

char *
xstrdup(s)
	const char *s;
{
	char *p = strdup(s);
	if (p == NULL)
		err(1, "strdup");
	return p;
}

void
usage()
{
	fprintf(stderr, "usage: m4 [-Dname[=val]] [-Uname] [-I dirname...]\n");
	exit(1);
}

int 
obtain_char(f)
	struct input_file *f;
{
	if (f->c == EOF)
		return EOF;
	else if (f->c == '\n')
		f->lineno++;

	f->c = fgetc(f->file);
	return f->c;
}

void 
set_input(f, real, name)
	struct input_file *f;
	FILE *real;
	const char *name;
{
	f->file = real;
	f->lineno = 1;
	f->c = 0;
	f->name = xstrdup(name);
}

void 
release_input(f)
	struct input_file *f;
{
	if (f->file != stdin)
	    fclose(f->file);
	f->c = EOF;
	/*
	 * XXX can't free filename, as there might still be 
	 * error information pointing to it.
	 */
}

void
doprintlineno(f)
	struct input_file *f;
{
	pbunsigned(f->lineno);
}

void
doprintfilename(f)
	struct input_file *f;
{
	pbstr(f->name);
}