xref: /freebsd/usr.bin/sed/process.c (revision 0b3105a37d7adcadcb720112fed4dc4e8040be99)
1 /*-
2  * Copyright (c) 1992 Diomidis Spinellis.
3  * Copyright (c) 1992, 1993, 1994
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * This code is derived from software contributed to Berkeley by
7  * Diomidis Spinellis of Imperial College, University of London.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #ifndef lint
38 static const char sccsid[] = "@(#)process.c	8.6 (Berkeley) 4/20/94";
39 #endif
40 
41 #include <sys/types.h>
42 #include <sys/stat.h>
43 #include <sys/ioctl.h>
44 #include <sys/uio.h>
45 
46 #include <ctype.h>
47 #include <err.h>
48 #include <errno.h>
49 #include <fcntl.h>
50 #include <limits.h>
51 #include <regex.h>
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <string.h>
55 #include <unistd.h>
56 #include <wchar.h>
57 #include <wctype.h>
58 
59 #include "defs.h"
60 #include "extern.h"
61 
62 static SPACE HS, PS, SS, YS;
63 #define	pd		PS.deleted
64 #define	ps		PS.space
65 #define	psl		PS.len
66 #define	psanl		PS.append_newline
67 #define	hs		HS.space
68 #define	hsl		HS.len
69 
70 static inline int	 applies(struct s_command *);
71 static void		 do_tr(struct s_tr *);
72 static void		 flush_appends(void);
73 static void		 lputs(char *, size_t);
74 static int		 regexec_e(regex_t *, const char *, int, int, size_t);
75 static void		 regsub(SPACE *, char *, char *);
76 static int		 substitute(struct s_command *);
77 
78 struct s_appends *appends;	/* Array of pointers to strings to append. */
79 static int appendx;		/* Index into appends array. */
80 int appendnum;			/* Size of appends array. */
81 
82 static int lastaddr;		/* Set by applies if last address of a range. */
83 static int sdone;		/* If any substitutes since last line input. */
84 				/* Iov structure for 'w' commands. */
85 static regex_t *defpreg;
86 size_t maxnsub;
87 regmatch_t *match;
88 
89 #define OUT() do {							\
90 	fwrite(ps, 1, psl, outfile);					\
91 	if (psanl) fputc('\n', outfile);				\
92 } while (0)
93 
94 void
95 process(void)
96 {
97 	struct s_command *cp;
98 	SPACE tspace;
99 	size_t oldpsl = 0;
100 	char *p;
101 	int oldpsanl;
102 
103 	p = NULL;
104 
105 	for (linenum = 0; mf_fgets(&PS, REPLACE);) {
106 		pd = 0;
107 top:
108 		cp = prog;
109 redirect:
110 		while (cp != NULL) {
111 			if (!applies(cp)) {
112 				cp = cp->next;
113 				continue;
114 			}
115 			switch (cp->code) {
116 			case '{':
117 				cp = cp->u.c;
118 				goto redirect;
119 			case 'a':
120 				if (appendx >= appendnum)
121 					if ((appends = realloc(appends,
122 					    sizeof(struct s_appends) *
123 					    (appendnum *= 2))) == NULL)
124 						err(1, "realloc");
125 				appends[appendx].type = AP_STRING;
126 				appends[appendx].s = cp->t;
127 				appends[appendx].len = strlen(cp->t);
128 				appendx++;
129 				break;
130 			case 'b':
131 				cp = cp->u.c;
132 				goto redirect;
133 			case 'c':
134 				pd = 1;
135 				psl = 0;
136 				if (cp->a2 == NULL || lastaddr || lastline())
137 					(void)fprintf(outfile, "%s", cp->t);
138 				break;
139 			case 'd':
140 				pd = 1;
141 				goto new;
142 			case 'D':
143 				if (pd)
144 					goto new;
145 				if (psl == 0 ||
146 				    (p = memchr(ps, '\n', psl)) == NULL) {
147 					pd = 1;
148 					goto new;
149 				} else {
150 					psl -= (p + 1) - ps;
151 					memmove(ps, p + 1, psl);
152 					goto top;
153 				}
154 			case 'g':
155 				cspace(&PS, hs, hsl, REPLACE);
156 				break;
157 			case 'G':
158 				cspace(&PS, "\n", 1, APPEND);
159 				cspace(&PS, hs, hsl, APPEND);
160 				break;
161 			case 'h':
162 				cspace(&HS, ps, psl, REPLACE);
163 				break;
164 			case 'H':
165 				cspace(&HS, "\n", 1, APPEND);
166 				cspace(&HS, ps, psl, APPEND);
167 				break;
168 			case 'i':
169 				(void)fprintf(outfile, "%s", cp->t);
170 				break;
171 			case 'l':
172 				lputs(ps, psl);
173 				break;
174 			case 'n':
175 				if (!nflag && !pd)
176 					OUT();
177 				flush_appends();
178 				if (!mf_fgets(&PS, REPLACE))
179 					exit(0);
180 				pd = 0;
181 				break;
182 			case 'N':
183 				flush_appends();
184 				cspace(&PS, "\n", 1, APPEND);
185 				if (!mf_fgets(&PS, APPEND))
186 					exit(0);
187 				break;
188 			case 'p':
189 				if (pd)
190 					break;
191 				OUT();
192 				break;
193 			case 'P':
194 				if (pd)
195 					break;
196 				if ((p = memchr(ps, '\n', psl)) != NULL) {
197 					oldpsl = psl;
198 					oldpsanl = psanl;
199 					psl = p - ps;
200 					psanl = 1;
201 				}
202 				OUT();
203 				if (p != NULL) {
204 					psl = oldpsl;
205 					psanl = oldpsanl;
206 				}
207 				break;
208 			case 'q':
209 				if (!nflag && !pd)
210 					OUT();
211 				flush_appends();
212 				exit(0);
213 			case 'r':
214 				if (appendx >= appendnum)
215 					if ((appends = realloc(appends,
216 					    sizeof(struct s_appends) *
217 					    (appendnum *= 2))) == NULL)
218 						err(1, "realloc");
219 				appends[appendx].type = AP_FILE;
220 				appends[appendx].s = cp->t;
221 				appends[appendx].len = strlen(cp->t);
222 				appendx++;
223 				break;
224 			case 's':
225 				sdone |= substitute(cp);
226 				break;
227 			case 't':
228 				if (sdone) {
229 					sdone = 0;
230 					cp = cp->u.c;
231 					goto redirect;
232 				}
233 				break;
234 			case 'w':
235 				if (pd)
236 					break;
237 				if (cp->u.fd == -1 && (cp->u.fd = open(cp->t,
238 				    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
239 				    DEFFILEMODE)) == -1)
240 					err(1, "%s", cp->t);
241 				if (write(cp->u.fd, ps, psl) != (ssize_t)psl ||
242 				    write(cp->u.fd, "\n", 1) != 1)
243 					err(1, "%s", cp->t);
244 				break;
245 			case 'x':
246 				/*
247 				 * If the hold space is null, make it empty
248 				 * but not null.  Otherwise the pattern space
249 				 * will become null after the swap, which is
250 				 * an abnormal condition.
251 				 */
252 				if (hs == NULL)
253 					cspace(&HS, "", 0, REPLACE);
254 				tspace = PS;
255 				PS = HS;
256 				psanl = tspace.append_newline;
257 				HS = tspace;
258 				break;
259 			case 'y':
260 				if (pd || psl == 0)
261 					break;
262 				do_tr(cp->u.y);
263 				break;
264 			case ':':
265 			case '}':
266 				break;
267 			case '=':
268 				(void)fprintf(outfile, "%lu\n", linenum);
269 			}
270 			cp = cp->next;
271 		} /* for all cp */
272 
273 new:		if (!nflag && !pd)
274 			OUT();
275 		flush_appends();
276 	} /* for all lines */
277 }
278 
279 /*
280  * TRUE if the address passed matches the current program state
281  * (lastline, linenumber, ps).
282  */
283 #define	MATCH(a)							\
284 	((a)->type == AT_RE ? regexec_e((a)->u.r, ps, 0, 1, psl) :	\
285 	    (a)->type == AT_LINE ? linenum == (a)->u.l : lastline())
286 
287 /*
288  * Return TRUE if the command applies to the current line.  Sets the start
289  * line for process ranges.  Interprets the non-select (``!'') flag.
290  */
291 static inline int
292 applies(struct s_command *cp)
293 {
294 	int r;
295 
296 	lastaddr = 0;
297 	if (cp->a1 == NULL && cp->a2 == NULL)
298 		r = 1;
299 	else if (cp->a2)
300 		if (cp->startline > 0) {
301                         switch (cp->a2->type) {
302                         case AT_RELLINE:
303                                 if (linenum - cp->startline <= cp->a2->u.l)
304                                         r = 1;
305                                 else {
306 				        cp->startline = 0;
307 				        r = 0;
308                                 }
309                                 break;
310                         default:
311                                 if (MATCH(cp->a2)) {
312                                         cp->startline = 0;
313                                         lastaddr = 1;
314                                         r = 1;
315                                 } else if (cp->a2->type == AT_LINE &&
316                                             linenum > cp->a2->u.l) {
317                                         /*
318                                          * We missed the 2nd address due to a
319                                          * branch, so just close the range and
320                                          * return false.
321                                          */
322                                         cp->startline = 0;
323                                         r = 0;
324                                 } else
325                                         r = 1;
326                         }
327 		} else if (cp->a1 && MATCH(cp->a1)) {
328 			/*
329 			 * If the second address is a number less than or
330 			 * equal to the line number first selected, only
331 			 * one line shall be selected.
332 			 *	-- POSIX 1003.2
333 			 * Likewise if the relative second line address is zero.
334 			 */
335 			if ((cp->a2->type == AT_LINE &&
336 			    linenum >= cp->a2->u.l) ||
337 			    (cp->a2->type == AT_RELLINE && cp->a2->u.l == 0))
338 				lastaddr = 1;
339 			else {
340 				cp->startline = linenum;
341 			}
342 			r = 1;
343 		} else
344 			r = 0;
345 	else
346 		r = MATCH(cp->a1);
347 	return (cp->nonsel ? ! r : r);
348 }
349 
350 /*
351  * Reset the sed processor to its initial state.
352  */
353 void
354 resetstate(void)
355 {
356 	struct s_command *cp;
357 
358 	/*
359 	 * Reset all in-range markers.
360 	 */
361 	for (cp = prog; cp; cp = cp->code == '{' ? cp->u.c : cp->next)
362 		if (cp->a2)
363 			cp->startline = 0;
364 
365 	/*
366 	 * Clear out the hold space.
367 	 */
368 	cspace(&HS, "", 0, REPLACE);
369 }
370 
371 /*
372  * substitute --
373  *	Do substitutions in the pattern space.  Currently, we build a
374  *	copy of the new pattern space in the substitute space structure
375  *	and then swap them.
376  */
377 static int
378 substitute(struct s_command *cp)
379 {
380 	SPACE tspace;
381 	regex_t *re;
382 	regoff_t re_off, slen;
383 	int lastempty, n;
384 	char *s;
385 
386 	s = ps;
387 	re = cp->u.s->re;
388 	if (re == NULL) {
389 		if (defpreg != NULL && cp->u.s->maxbref > defpreg->re_nsub) {
390 			linenum = cp->u.s->linenum;
391 			errx(1, "%lu: %s: \\%u not defined in the RE",
392 					linenum, fname, cp->u.s->maxbref);
393 		}
394 	}
395 	if (!regexec_e(re, s, 0, 0, psl))
396 		return (0);
397 
398 	SS.len = 0;				/* Clean substitute space. */
399 	slen = psl;
400 	n = cp->u.s->n;
401 	lastempty = 1;
402 
403 	switch (n) {
404 	case 0:					/* Global */
405 		do {
406 			if (lastempty || match[0].rm_so != match[0].rm_eo) {
407 				/* Locate start of replaced string. */
408 				re_off = match[0].rm_so;
409 				/* Copy leading retained string. */
410 				cspace(&SS, s, re_off, APPEND);
411 				/* Add in regular expression. */
412 				regsub(&SS, s, cp->u.s->new);
413 			}
414 
415 			/* Move past this match. */
416 			if (match[0].rm_so != match[0].rm_eo) {
417 				s += match[0].rm_eo;
418 				slen -= match[0].rm_eo;
419 				lastempty = 0;
420 			} else {
421 				if (match[0].rm_so < slen)
422 					cspace(&SS, s + match[0].rm_so, 1,
423 					    APPEND);
424 				s += match[0].rm_so + 1;
425 				slen -= match[0].rm_so + 1;
426 				lastempty = 1;
427 			}
428 		} while (slen >= 0 && regexec_e(re, s, REG_NOTBOL, 0, slen));
429 		/* Copy trailing retained string. */
430 		if (slen > 0)
431 			cspace(&SS, s, slen, APPEND);
432 		break;
433 	default:				/* Nth occurrence */
434 		while (--n) {
435 			if (match[0].rm_eo == match[0].rm_so)
436 				match[0].rm_eo = match[0].rm_so + 1;
437 			s += match[0].rm_eo;
438 			slen -= match[0].rm_eo;
439 			if (slen < 0)
440 				return (0);
441 			if (!regexec_e(re, s, REG_NOTBOL, 0, slen))
442 				return (0);
443 		}
444 		/* FALLTHROUGH */
445 	case 1:					/* 1st occurrence */
446 		/* Locate start of replaced string. */
447 		re_off = match[0].rm_so + (s - ps);
448 		/* Copy leading retained string. */
449 		cspace(&SS, ps, re_off, APPEND);
450 		/* Add in regular expression. */
451 		regsub(&SS, s, cp->u.s->new);
452 		/* Copy trailing retained string. */
453 		s += match[0].rm_eo;
454 		slen -= match[0].rm_eo;
455 		cspace(&SS, s, slen, APPEND);
456 		break;
457 	}
458 
459 	/*
460 	 * Swap the substitute space and the pattern space, and make sure
461 	 * that any leftover pointers into stdio memory get lost.
462 	 */
463 	tspace = PS;
464 	PS = SS;
465 	psanl = tspace.append_newline;
466 	SS = tspace;
467 	SS.space = SS.back;
468 
469 	/* Handle the 'p' flag. */
470 	if (cp->u.s->p)
471 		OUT();
472 
473 	/* Handle the 'w' flag. */
474 	if (cp->u.s->wfile && !pd) {
475 		if (cp->u.s->wfd == -1 && (cp->u.s->wfd = open(cp->u.s->wfile,
476 		    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, DEFFILEMODE)) == -1)
477 			err(1, "%s", cp->u.s->wfile);
478 		if (write(cp->u.s->wfd, ps, psl) != (ssize_t)psl ||
479 		    write(cp->u.s->wfd, "\n", 1) != 1)
480 			err(1, "%s", cp->u.s->wfile);
481 	}
482 	return (1);
483 }
484 
485 /*
486  * do_tr --
487  *	Perform translation ('y' command) in the pattern space.
488  */
489 static void
490 do_tr(struct s_tr *y)
491 {
492 	SPACE tmp;
493 	char c, *p;
494 	size_t clen, left;
495 	int i;
496 
497 	if (MB_CUR_MAX == 1) {
498 		/*
499 		 * Single-byte encoding: perform in-place translation
500 		 * of the pattern space.
501 		 */
502 		for (p = ps; p < &ps[psl]; p++)
503 			*p = y->bytetab[(u_char)*p];
504 	} else {
505 		/*
506 		 * Multi-byte encoding: perform translation into the
507 		 * translation space, then swap the translation and
508 		 * pattern spaces.
509 		 */
510 		/* Clean translation space. */
511 		YS.len = 0;
512 		for (p = ps, left = psl; left > 0; p += clen, left -= clen) {
513 			if ((c = y->bytetab[(u_char)*p]) != '\0') {
514 				cspace(&YS, &c, 1, APPEND);
515 				clen = 1;
516 				continue;
517 			}
518 			for (i = 0; i < y->nmultis; i++)
519 				if (left >= y->multis[i].fromlen &&
520 				    memcmp(p, y->multis[i].from,
521 				    y->multis[i].fromlen) == 0)
522 					break;
523 			if (i < y->nmultis) {
524 				cspace(&YS, y->multis[i].to,
525 				    y->multis[i].tolen, APPEND);
526 				clen = y->multis[i].fromlen;
527 			} else {
528 				cspace(&YS, p, 1, APPEND);
529 				clen = 1;
530 			}
531 		}
532 		/* Swap the translation space and the pattern space. */
533 		tmp = PS;
534 		PS = YS;
535 		psanl = tmp.append_newline;
536 		YS = tmp;
537 		YS.space = YS.back;
538 	}
539 }
540 
541 /*
542  * Flush append requests.  Always called before reading a line,
543  * therefore it also resets the substitution done (sdone) flag.
544  */
545 static void
546 flush_appends(void)
547 {
548 	FILE *f;
549 	int count, i;
550 	char buf[8 * 1024];
551 
552 	for (i = 0; i < appendx; i++)
553 		switch (appends[i].type) {
554 		case AP_STRING:
555 			fwrite(appends[i].s, sizeof(char), appends[i].len,
556 			    outfile);
557 			break;
558 		case AP_FILE:
559 			/*
560 			 * Read files probably shouldn't be cached.  Since
561 			 * it's not an error to read a non-existent file,
562 			 * it's possible that another program is interacting
563 			 * with the sed script through the filesystem.  It
564 			 * would be truly bizarre, but possible.  It's probably
565 			 * not that big a performance win, anyhow.
566 			 */
567 			if ((f = fopen(appends[i].s, "r")) == NULL)
568 				break;
569 			while ((count = fread(buf, sizeof(char), sizeof(buf), f)))
570 				(void)fwrite(buf, sizeof(char), count, outfile);
571 			(void)fclose(f);
572 			break;
573 		}
574 	if (ferror(outfile))
575 		errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
576 	appendx = sdone = 0;
577 }
578 
579 static void
580 lputs(char *s, size_t len)
581 {
582 	static const char escapes[] = "\\\a\b\f\r\t\v";
583 	int c, col, width;
584 	const char *p;
585 	struct winsize win;
586 	static int termwidth = -1;
587 	size_t clen, i;
588 	wchar_t wc;
589 	mbstate_t mbs;
590 
591 	if (outfile != stdout)
592 		termwidth = 60;
593 	if (termwidth == -1) {
594 		if ((p = getenv("COLUMNS")) && *p != '\0')
595 			termwidth = atoi(p);
596 		else if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) == 0 &&
597 		    win.ws_col > 0)
598 			termwidth = win.ws_col;
599 		else
600 			termwidth = 60;
601 	}
602 	if (termwidth <= 0)
603 		termwidth = 1;
604 
605 	memset(&mbs, 0, sizeof(mbs));
606 	col = 0;
607 	while (len != 0) {
608 		clen = mbrtowc(&wc, s, len, &mbs);
609 		if (clen == 0)
610 			clen = 1;
611 		if (clen == (size_t)-1 || clen == (size_t)-2) {
612 			wc = (unsigned char)*s;
613 			clen = 1;
614 			memset(&mbs, 0, sizeof(mbs));
615 		}
616 		if (wc == '\n') {
617 			if (col + 1 >= termwidth)
618 				fprintf(outfile, "\\\n");
619 			fputc('$', outfile);
620 			fputc('\n', outfile);
621 			col = 0;
622 		} else if (iswprint(wc)) {
623 			width = wcwidth(wc);
624 			if (col + width >= termwidth) {
625 				fprintf(outfile, "\\\n");
626 				col = 0;
627 			}
628 			fwrite(s, 1, clen, outfile);
629 			col += width;
630 		} else if (wc != L'\0' && (c = wctob(wc)) != EOF &&
631 		    (p = strchr(escapes, c)) != NULL) {
632 			if (col + 2 >= termwidth) {
633 				fprintf(outfile, "\\\n");
634 				col = 0;
635 			}
636 			fprintf(outfile, "\\%c", "\\abfrtv"[p - escapes]);
637 			col += 2;
638 		} else {
639 			if (col + 4 * clen >= (unsigned)termwidth) {
640 				fprintf(outfile, "\\\n");
641 				col = 0;
642 			}
643 			for (i = 0; i < clen; i++)
644 				fprintf(outfile, "\\%03o",
645 				    (int)(unsigned char)s[i]);
646 			col += 4 * clen;
647 		}
648 		s += clen;
649 		len -= clen;
650 	}
651 	if (col + 1 >= termwidth)
652 		fprintf(outfile, "\\\n");
653 	(void)fputc('$', outfile);
654 	(void)fputc('\n', outfile);
655 	if (ferror(outfile))
656 		errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
657 }
658 
659 static int
660 regexec_e(regex_t *preg, const char *string, int eflags, int nomatch,
661 	size_t slen)
662 {
663 	int eval;
664 
665 	if (preg == NULL) {
666 		if (defpreg == NULL)
667 			errx(1, "first RE may not be empty");
668 	} else
669 		defpreg = preg;
670 
671 	/* Set anchors */
672 	match[0].rm_so = 0;
673 	match[0].rm_eo = slen;
674 
675 	eval = regexec(defpreg, string,
676 	    nomatch ? 0 : maxnsub + 1, match, eflags | REG_STARTEND);
677 	switch(eval) {
678 	case 0:
679 		return (1);
680 	case REG_NOMATCH:
681 		return (0);
682 	}
683 	errx(1, "RE error: %s", strregerror(eval, defpreg));
684 	/* NOTREACHED */
685 }
686 
687 /*
688  * regsub - perform substitutions after a regexp match
689  * Based on a routine by Henry Spencer
690  */
691 static void
692 regsub(SPACE *sp, char *string, char *src)
693 {
694 	int len, no;
695 	char c, *dst;
696 
697 #define	NEEDSP(reqlen)							\
698 	/* XXX What is the +1 for? */					\
699 	if (sp->len + (reqlen) + 1 >= sp->blen) {			\
700 		sp->blen += (reqlen) + 1024;				\
701 		if ((sp->space = sp->back = realloc(sp->back, sp->blen)) \
702 		    == NULL)						\
703 			err(1, "realloc");				\
704 		dst = sp->space + sp->len;				\
705 	}
706 
707 	dst = sp->space + sp->len;
708 	while ((c = *src++) != '\0') {
709 		if (c == '&')
710 			no = 0;
711 		else if (c == '\\' && isdigit((unsigned char)*src))
712 			no = *src++ - '0';
713 		else
714 			no = -1;
715 		if (no < 0) {		/* Ordinary character. */
716 			if (c == '\\' && (*src == '\\' || *src == '&'))
717 				c = *src++;
718 			NEEDSP(1);
719 			*dst++ = c;
720 			++sp->len;
721 		} else if (match[no].rm_so != -1 && match[no].rm_eo != -1) {
722 			len = match[no].rm_eo - match[no].rm_so;
723 			NEEDSP(len);
724 			memmove(dst, string + match[no].rm_so, len);
725 			dst += len;
726 			sp->len += len;
727 		}
728 	}
729 	NEEDSP(1);
730 	*dst = '\0';
731 }
732 
733 /*
734  * cspace --
735  *	Concatenate space: append the source space to the destination space,
736  *	allocating new space as necessary.
737  */
738 void
739 cspace(SPACE *sp, const char *p, size_t len, enum e_spflag spflag)
740 {
741 	size_t tlen;
742 
743 	/* Make sure SPACE has enough memory and ramp up quickly. */
744 	tlen = sp->len + len + 1;
745 	if (tlen > sp->blen) {
746 		sp->blen = tlen + 1024;
747 		if ((sp->space = sp->back = realloc(sp->back, sp->blen)) ==
748 		    NULL)
749 			err(1, "realloc");
750 	}
751 
752 	if (spflag == REPLACE)
753 		sp->len = 0;
754 
755 	memmove(sp->space + sp->len, p, len);
756 
757 	sp->space[sp->len += len] = '\0';
758 }
759 
760 /*
761  * Close all cached opened files and report any errors
762  */
763 void
764 cfclose(struct s_command *cp, struct s_command *end)
765 {
766 
767 	for (; cp != end; cp = cp->next)
768 		switch(cp->code) {
769 		case 's':
770 			if (cp->u.s->wfd != -1 && close(cp->u.s->wfd))
771 				err(1, "%s", cp->u.s->wfile);
772 			cp->u.s->wfd = -1;
773 			break;
774 		case 'w':
775 			if (cp->u.fd != -1 && close(cp->u.fd))
776 				err(1, "%s", cp->t);
777 			cp->u.fd = -1;
778 			break;
779 		case '{':
780 			cfclose(cp->u.c, cp->next);
781 			break;
782 		}
783 }
784