Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	usr.bin/m4/misc.c	Lines:	108	171	63.2 %
Date:	2017-11-13	Branches:	43	88	48.9 %


/*	$OpenBSD: misc.c,v 1.47 2017/06/15 13:48:42 bcallah 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. 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.
 */

#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdint.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 */
char *endest;		/* end of string space	       */
static size_t strsize = STRSPMAX;
static size_t bufsize = BUFSIZE;

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


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

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

/*
 *  pbstr - push string back onto input
 *          pushback is replicated to improve
 *          performance.
 */
void
pbstr(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(int n)
{
	pbnumbase(n, 10, 0);
}

void
pbnumbase(int n, int base, int d)
{
	static char digits[36] = "0123456789abcdefghijklmnopqrstuvwxyz";
	int num;
	int printed = 0;

	if (base > 36)
		m4errx(1, "base %d > 36: not supported.", base);

	if (base < 2)
		m4errx(1, "bad base %d for conversion.", base);

	num = (n < 0) ? -n : n;
	do {
		pushback(digits[num % base]);
		printed++;
	}
	while ((num /= base) > 0);

	if (n < 0)
		printed++;
	while (printed++ < d)
		pushback('0');

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

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

void
initspaces()
{
	int i;

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

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] == STORAGE_STRSPACE)
			mstack[i].sstr = (mstack[i].sstr - strspace)
			    + newstrspace;
	ep = (ep-strspace) + newstrspace;
	free(strspace);
	strspace = newstrspace;
	endest = strspace + strsize;
}

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

	bufsize += bufsize/2;
	newbuf = xrealloc(buf, bufsize, "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(int c)
{
	if (ep >= endest)
		enlarge_strspace();
	*ep++ = c;
}

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

	if (active == outfile[n])
		m4errx(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(int signo)
{
#define intrmessage	"m4: interrupted.\n"
	write(STDERR_FILENO, intrmessage, sizeof(intrmessage)-1);
	_exit(1);
}

/*
 * 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]);
		}
}

extern char *__progname;

void
m4errx(int eval, const char *fmt, ...)
{
	fprintf(stderr, "%s: ", __progname);
	fprintf(stderr, "%s at line %lu: ", CURRENT_NAME, CURRENT_LINE);
	if (fmt != NULL) {
		va_list ap;

		va_start(ap, fmt);
		vfprintf(stderr, fmt, ap);
		va_end(ap);
	}
	fprintf(stderr, "\n");
	exit(eval);
}

/*
 * resizedivs: allocate more diversion files */
void
resizedivs(int n)
{
	int i;

	outfile = xreallocarray(outfile, n, sizeof(FILE *),
	    "too many diverts %d", n);
	for (i = maxout; i < n; i++)
		outfile[i] = NULL;
	maxout = n;
}

void *
xalloc(size_t n, const char *fmt, ...)
{
	void *p = malloc(n);

	if (p == NULL) {
		if (fmt == NULL)
			err(1, "malloc");
		else {
			va_list va;

			va_start(va, fmt);
			verr(1, fmt, va);
			va_end(va);
		}
	}
	return p;
}

void *
xcalloc(size_t n, size_t s, const char *fmt, ...)
{
	void *p = calloc(n, s);

	if (p == NULL) {
		if (fmt == NULL)
			err(1, "calloc");
		else {
			va_list va;

			va_start(va, fmt);
			verr(1, fmt, va);
			va_end(va);
		}
	}
	return p;
}

void *
xrealloc(void *old, size_t n, const char *fmt, ...)
{
	char *p = realloc(old, n);

	if (p == NULL) {
		free(old);
		if (fmt == NULL)
			err(1, "realloc");
		else {
			va_list va;

			va_start(va, fmt);
			verr(1, fmt, va);
			va_end(va);
		}
	}
	return p;
}

void *
xreallocarray(void *old, size_t s1, size_t s2, const char *fmt, ...)
{
	void *p = reallocarray(old, s1, s2);

	if (p == NULL) {
		free(old);
		if (fmt == NULL)
			err(1, "reallocarray");
		else {
			va_list va;

			va_start(va, fmt);
			verr(1, fmt, va);
			va_end(va);
		}
	}
	return p;
}

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

void
usage(void)
{
	fprintf(stderr, "usage: m4 [-EgPs] [-Dname[=value]] [-d flags] "
			"[-I dirname] [-o filename]\n"
			"\t[-t macro] [-Uname] [file ...]\n");
	exit(1);
}

int
obtain_char(struct input_file *f)
{
	if (f->c == EOF)
		return EOF;

	f->c = fgetc(f->file);
	if (f->c == '\n')
		f->lineno++;

	return f->c;
}

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

void
do_emit_synchline()
{
	fprintf(active, "#line %lu \"%s\"\n",
	    infile[ilevel].lineno, infile[ilevel].name);
	infile[ilevel].synch_lineno = infile[ilevel].lineno;
}

void
release_input(struct input_file *f)
{
	if (ferror(f->file))
		errx(1, "Fatal error reading from %s\n", f->name);
	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(struct input_file *f)
{
	pbunsigned(f->lineno);
}

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

/*
 * buffer_mark/dump_buffer: allows one to save a mark in a buffer,
 * and later dump everything that was added since then to a file.
 */
size_t
buffer_mark()
{
	return bp - buf;
}


void
dump_buffer(FILE *f, size_t m)
{
	unsigned char *s;

	for (s = bp; s-buf > m;)
		fputc(*--s, f);
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: misc.c,v 1.47 2017/06/15 13:48:42 bcallah Exp $ */
2			/* $NetBSD: misc.c,v 1.6 1995/09/28 05:37:41 tls Exp $ */
3
4			/*
5			* Copyright (c) 1989, 1993
6			* The Regents of the University of California. All rights reserved.
7			*
8			* This code is derived from software contributed to Berkeley by
9			* Ozan Yigit at York University.
10			*
11			* Redistribution and use in source and binary forms, with or without
12			* modification, are permitted provided that the following conditions
13			* are met:
14			* 1. Redistributions of source code must retain the above copyright
15			* notice, this list of conditions and the following disclaimer.
16			* 2. Redistributions in binary form must reproduce the above copyright
17			* notice, this list of conditions and the following disclaimer in the
18			* documentation and/or other materials provided with the distribution.
19			* 3. Neither the name of the University nor the names of its contributors
20			* may be used to endorse or promote products derived from this software
21			* without specific prior written permission.
22			*
23			* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24			* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26			* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27			* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28			* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29			* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31			* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32			* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33			* SUCH DAMAGE.
34			*/
35
36			#include <sys/types.h>
37			#include <errno.h>
38			#include <unistd.h>
39			#include <stdarg.h>
40			#include <stdio.h>
41			#include <stdint.h>
42			#include <stdlib.h>
43			#include <stddef.h>
44			#include <string.h>
45			#include <err.h>
46			#include "mdef.h"
47			#include "stdd.h"
48			#include "extern.h"
49			#include "pathnames.h"
50
51
52			char ep; / first free char in strspace */
53			static char strspace; / string space for evaluation */
54			char endest; / end of string space */
55			static size_t strsize = STRSPMAX;
56			static size_t bufsize = BUFSIZE;
57
58			unsigned char buf; / push-back buffer */
59			unsigned char bufbase; / the base for current ilevel */
60			unsigned char bbase[MAXINP]; / the base for each ilevel */
61			unsigned char bp; / first available character */
62			unsigned char endpbb; / end of push-back buffer */
63
64
65			/*
66			* find the index of second str in the first str.
67			*/
68			ptrdiff_t
69			indx(const char s1, const char s2)
70			{
71			char *t;
72
73			t = strstr(s1, s2);
74			if (t == NULL)
75			return (-1);
76			else
77			return (t - s1);
78			}
79			/*
80			* pushback - push character back onto input
81			*/
82			void
83			pushback(int c)
84			{
85	✓✓	44999724	if (c == EOF)
86			return;
87	✗✓	22499857	if (bp >= endpbb)
88			enlarge_bufspace();
89		22499857	*bp++ = c;
90		44999719	}
91
92			/*
93			* pbstr - push string back onto input
94			* pushback is replicated to improve
95			* performance.
96			*/
97			void
98			pbstr(const char *s)
99			{
100			size_t n;
101
102		14583086	n = strlen(s);
103	✓✓	14583232	while (endpbb - bp <= n)
104		73	enlarge_bufspace();
105	✓✓	104134018	while (n > 0)
106		44775466	*bp++ = s[--n];
107		7291543	}
108
109			/*
110			* pbnum - convert number to string, push back on input.
111			*/
112			void
113			pbnum(int n)
114			{
115		3643492	pbnumbase(n, 10, 0);
116		1821746	}
117
118			void
119			pbnumbase(int n, int base, int d)
120			{
121			static char digits[36] = "0123456789abcdefghijklmnopqrstuvwxyz";
122			int num;
123			int printed = 0;
124
125	✗✓	3643552	if (base > 36)
126			m4errx(1, "base %d > 36: not supported.", base);
127
128	✗✓	1821776	if (base < 2)
129			m4errx(1, "bad base %d for conversion.", base);
130
131		1821776	num = (n < 0) ? -n : n;
132		1821776	do {
133		1842711	pushback(digits[num % base]);
134		1842711	printed++;
135	✓✓	1842711	}
136		1842711	while ((num /= base) > 0);
137
138	✓✓	1821776	if (n < 0)
139		5	printed++;
140	✗✓	3643552	while (printed++ < d)
141			pushback('0');
142
143	✓✓	1821776	if (n < 0)
144		5	pushback('-');
145		1821776	}
146
147			/*
148			* pbunsigned - convert unsigned long to string, push back on input.
149			*/
150			void
151			pbunsigned(unsigned long n)
152			{
153			do {
154			pushback(n % 10 + '0');
155			}
156			while ((n /= 10) > 0);
157			}
158
159			void
160			initspaces()
161			{
162			int i;
163
164		378	strspace = xalloc(strsize+1, NULL);
165		189	ep = strspace;
166		189	endest = strspace+strsize;
167		189	buf = xalloc(bufsize, NULL);
168		189	bufbase = buf;
169		189	bp = buf;
170		189	endpbb = buf + bufsize;
171	✓✓	4158	for (i = 0; i < MAXINP; i++)
172		1890	bbase[i] = buf;
173		189	}
174
175			void
176			enlarge_strspace()
177			{
178			char *newstrspace;
179			int i;
180
181		82	strsize *= 2;
182		41	newstrspace = malloc(strsize + 1);
183	✗✓	41	if (!newstrspace)
184			errx(1, "string space overflow");
185		41	memcpy(newstrspace, strspace, strsize/2);
186	✓✓	7078	for (i = 0; i <= sp; i++)
187	✓✓	3498	if (sstack[i] == STORAGE_STRSPACE)
188		1284	mstack[i].sstr = (mstack[i].sstr - strspace)
189		642	+ newstrspace;
190		41	ep = (ep-strspace) + newstrspace;
191		41	free(strspace);
192		41	strspace = newstrspace;
193		41	endest = strspace + strsize;
194		41	}
195
196			void
197			enlarge_bufspace()
198			{
199			unsigned char *newbuf;
200			int i;
201
202		146	bufsize += bufsize/2;
203		73	newbuf = xrealloc(buf, bufsize, "too many characters pushed back");
204	✓✓	1606	for (i = 0; i < MAXINP; i++)
205		730	bbase[i] = (bbase[i]-buf)+newbuf;
206		73	bp = (bp-buf)+newbuf;
207		73	bufbase = (bufbase-buf)+newbuf;
208		73	buf = newbuf;
209		73	endpbb = buf+bufsize;
210		73	}
211
212			/*
213			* chrsave - put single char on string space
214			*/
215			void
216			chrsave(int c)
217			{
218	✓✓	30373516	if (ep >= endest)
219		25	enlarge_strspace();
220		15186758	*ep++ = c;
221		15186758	}
222
223			/*
224			* read in a diversion file, and dispose it.
225			*/
226			void
227			getdiv(int n)
228			{
229			int c;
230
231			if (active == outfile[n])
232			m4errx(1, "undivert: diversion still active.");
233			rewind(outfile[n]);
234			while ((c = getc(outfile[n])) != EOF)
235			putc(c, active);
236			(void) fclose(outfile[n]);
237			outfile[n] = NULL;
238			}
239
240			void
241			onintr(int signo)
242			{
243			#define intrmessage "m4: interrupted.\n"
244			write(STDERR_FILENO, intrmessage, sizeof(intrmessage)-1);
245			_exit(1);
246			}
247
248			/*
249			* killdiv - get rid of the diversion files
250			*/
251			void
252			killdiv()
253			{
254			int n;
255
256			for (n = 0; n < maxout; n++)
257			if (outfile[n] != NULL) {
258			(void) fclose(outfile[n]);
259			}
260			}
261
262			extern char *__progname;
263
264			void
265			m4errx(int eval, const char *fmt, ...)
266			{
267			fprintf(stderr, "%s: ", __progname);
268			fprintf(stderr, "%s at line %lu: ", CURRENT_NAME, CURRENT_LINE);
269			if (fmt != NULL) {
270			va_list ap;
271
272			va_start(ap, fmt);
273			vfprintf(stderr, fmt, ap);
274			va_end(ap);
275			}
276			fprintf(stderr, "\n");
277			exit(eval);
278			}
279
280			/*
281			* resizedivs: allocate more diversion files */
282			void
283			resizedivs(int n)
284			{
285			int i;
286
287		378	outfile = xreallocarray(outfile, n, sizeof(FILE *),
288			"too many diverts %d", n);
289	✓✓	4158	for (i = maxout; i < n; i++)
290		1890	outfile[i] = NULL;
291		189	maxout = n;
292		189	}
293
294			void *
295			xalloc(size_t n, const char *fmt, ...)
296			{
297		37282	void *p = malloc(n);
298
299	✗✓	18641	if (p == NULL) {
300			if (fmt == NULL)
301			err(1, "malloc");
302			else {
303			va_list va;
304
305			va_start(va, fmt);
306			verr(1, fmt, va);
307			va_end(va);
308			}
309			}
310		18641	return p;
311			}
312
313			void *
314			xcalloc(size_t n, size_t s, const char *fmt, ...)
315			{
316		378	void *p = calloc(n, s);
317
318	✗✓	189	if (p == NULL) {
319			if (fmt == NULL)
320			err(1, "calloc");
321			else {
322			va_list va;
323
324			va_start(va, fmt);
325			verr(1, fmt, va);
326			va_end(va);
327			}
328			}
329		189	return p;
330			}
331
332			void *
333			xrealloc(void old, size_t n, const char fmt, ...)
334			{
335		226	char *p = realloc(old, n);
336
337	✗✓	113	if (p == NULL) {
338			free(old);
339			if (fmt == NULL)
340			err(1, "realloc");
341			else {
342			va_list va;
343
344			va_start(va, fmt);
345			verr(1, fmt, va);
346			va_end(va);
347			}
348			}
349		113	return p;
350			}
351
352			void *
353			xreallocarray(void old, size_t s1, size_t s2, const char fmt, ...)
354			{
355		876	void *p = reallocarray(old, s1, s2);
356
357	✗✓	438	if (p == NULL) {
358			free(old);
359			if (fmt == NULL)
360			err(1, "reallocarray");
361			else {
362			va_list va;
363
364			va_start(va, fmt);
365			verr(1, fmt, va);
366			va_end(va);
367			}
368			}
369		438	return p;
370			}
371
372			char *
373			xstrdup(const char *s)
374			{
375		17216	char *p = strdup(s);
376	✗✓	8608	if (p == NULL)
377			err(1, "strdup");
378		8608	return p;
379			}
380
381			void
382			usage(void)
383			{
384			fprintf(stderr, "usage: m4 [-EgPs] [-Dname[=value]] [-d flags] "
385			"[-I dirname] [-o filename]\n"
386			"\t[-t macro] [-Uname] [file ...]\n");
387			exit(1);
388			}
389
390			int
391			obtain_char(struct input_file *f)
392			{
393	✓✓	1366844	if (f->c == EOF)
394		50	return EOF;
395
396		683372	f->c = fgetc(f->file);
397	✓✓	683372	if (f->c == '\n')
398		20798	f->lineno++;
399
400		683372	return f->c;
401		683422	}
402
403			void
404			set_input(struct input_file f, FILE real, const char *name)
405			{
406		398	f->file = real;
407		199	f->lineno = 1;
408		199	f->c = 0;
409		199	f->name = xstrdup(name);
410	✓✓	209	emit_synchline();
411		199	}
412
413			void
414			do_emit_synchline()
415			{
416		120	fprintf(active, "#line %lu \"%s\"\n",
417		40	infile[ilevel].lineno, infile[ilevel].name);
418		40	infile[ilevel].synch_lineno = infile[ilevel].lineno;
419		40	}
420
421			void
422			release_input(struct input_file *f)
423			{
424	✓✗✗✓ ✗✗	510	if (ferror(f->file))
425			errx(1, "Fatal error reading from %s\n", f->name);
426	✓✗	170	if (f->file != stdin)
427		170	fclose(f->file);
428		170	f->c = EOF;
429			/*
430			* XXX can't free filename, as there might still be
431			* error information pointing to it.
432			*/
433		170	}
434
435			void
436			doprintlineno(struct input_file *f)
437			{
438			pbunsigned(f->lineno);
439			}
440
441			void
442			doprintfilename(struct input_file *f)
443			{
444		10	pbstr(rquote);
445		5	pbstr(f->name);
446		5	pbstr(lquote);
447		5	}
448
449			/*
450			* buffer_mark/dump_buffer: allows one to save a mark in a buffer,
451			* and later dump everything that was added since then to a file.
452			*/
453			size_t
454			buffer_mark()
455			{
456			return bp - buf;
457			}
458
459
460			void
461			dump_buffer(FILE *f, size_t m)
462			{
463			unsigned char *s;
464
465			for (s = bp; s-buf > m;)
466			fputc(*--s, f);
467			}