xref: /freebsd/usr.bin/sed/process.c (revision 91ebf7d76582a73ac4c0a32964e4d3912010671e)
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 			     size_t);
76 static void		 regsub(SPACE *, char *, char *);
77 static int		 substitute(struct s_command *);
78 
79 struct s_appends *appends;	/* Array of pointers to strings to append. */
80 static int appendx;		/* Index into appends array. */
81 int appendnum;			/* Size of appends array. */
82 
83 static int lastaddr;		/* Set by applies if last address of a range. */
84 static int sdone;		/* If any substitutes since last line input. */
85 				/* Iov structure for 'w' commands. */
86 static regex_t *defpreg;
87 size_t maxnsub;
88 regmatch_t *match;
89 
90 #define OUT() do {							\
91 	fwrite(ps, 1, psl, outfile);					\
92 	if (psanl) fputc('\n', outfile);				\
93 } while (0)
94 
95 void
96 process(void)
97 {
98 	struct s_command *cp;
99 	SPACE tspace;
100 	size_t oldpsl = 0;
101 	char *p;
102 	int oldpsanl;
103 
104 	p = NULL;
105 
106 	for (linenum = 0; mf_fgets(&PS, REPLACE);) {
107 		pd = 0;
108 top:
109 		cp = prog;
110 redirect:
111 		while (cp != NULL) {
112 			if (!applies(cp)) {
113 				cp = cp->next;
114 				continue;
115 			}
116 			switch (cp->code) {
117 			case '{':
118 				cp = cp->u.c;
119 				goto redirect;
120 			case 'a':
121 				if (appendx >= appendnum)
122 					if ((appends = realloc(appends,
123 					    sizeof(struct s_appends) *
124 					    (appendnum *= 2))) == NULL)
125 						err(1, "realloc");
126 				appends[appendx].type = AP_STRING;
127 				appends[appendx].s = cp->t;
128 				appends[appendx].len = strlen(cp->t);
129 				appendx++;
130 				break;
131 			case 'b':
132 				cp = cp->u.c;
133 				goto redirect;
134 			case 'c':
135 				pd = 1;
136 				psl = 0;
137 				if (cp->a2 == NULL || lastaddr || lastline())
138 					(void)fprintf(outfile, "%s", cp->t);
139 				break;
140 			case 'd':
141 				pd = 1;
142 				goto new;
143 			case 'D':
144 				if (pd)
145 					goto new;
146 				if (psl == 0 ||
147 				    (p = memchr(ps, '\n', psl)) == NULL) {
148 					pd = 1;
149 					goto new;
150 				} else {
151 					psl -= (p + 1) - ps;
152 					memmove(ps, p + 1, psl);
153 					goto top;
154 				}
155 			case 'g':
156 				cspace(&PS, hs, hsl, REPLACE);
157 				break;
158 			case 'G':
159 				cspace(&PS, "\n", 1, APPEND);
160 				cspace(&PS, hs, hsl, APPEND);
161 				break;
162 			case 'h':
163 				cspace(&HS, ps, psl, REPLACE);
164 				break;
165 			case 'H':
166 				cspace(&HS, "\n", 1, APPEND);
167 				cspace(&HS, ps, psl, APPEND);
168 				break;
169 			case 'i':
170 				(void)fprintf(outfile, "%s", cp->t);
171 				break;
172 			case 'l':
173 				lputs(ps, psl);
174 				break;
175 			case 'n':
176 				if (!nflag && !pd)
177 					OUT();
178 				flush_appends();
179 				if (!mf_fgets(&PS, REPLACE))
180 					exit(0);
181 				pd = 0;
182 				break;
183 			case 'N':
184 				flush_appends();
185 				cspace(&PS, "\n", 1, APPEND);
186 				if (!mf_fgets(&PS, APPEND))
187 					exit(0);
188 				break;
189 			case 'p':
190 				if (pd)
191 					break;
192 				OUT();
193 				break;
194 			case 'P':
195 				if (pd)
196 					break;
197 				if ((p = memchr(ps, '\n', psl)) != NULL) {
198 					oldpsl = psl;
199 					oldpsanl = psanl;
200 					psl = p - ps;
201 					psanl = 1;
202 				}
203 				OUT();
204 				if (p != NULL) {
205 					psl = oldpsl;
206 					psanl = oldpsanl;
207 				}
208 				break;
209 			case 'q':
210 				if (!nflag && !pd)
211 					OUT();
212 				flush_appends();
213 				exit(0);
214 			case 'r':
215 				if (appendx >= appendnum)
216 					if ((appends = realloc(appends,
217 					    sizeof(struct s_appends) *
218 					    (appendnum *= 2))) == NULL)
219 						err(1, "realloc");
220 				appends[appendx].type = AP_FILE;
221 				appends[appendx].s = cp->t;
222 				appends[appendx].len = strlen(cp->t);
223 				appendx++;
224 				break;
225 			case 's':
226 				sdone |= substitute(cp);
227 				break;
228 			case 't':
229 				if (sdone) {
230 					sdone = 0;
231 					cp = cp->u.c;
232 					goto redirect;
233 				}
234 				break;
235 			case 'w':
236 				if (pd)
237 					break;
238 				if (cp->u.fd == -1 && (cp->u.fd = open(cp->t,
239 				    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
240 				    DEFFILEMODE)) == -1)
241 					err(1, "%s", cp->t);
242 				if (write(cp->u.fd, ps, psl) != (ssize_t)psl ||
243 				    write(cp->u.fd, "\n", 1) != 1)
244 					err(1, "%s", cp->t);
245 				break;
246 			case 'x':
247 				/*
248 				 * If the hold space is null, make it empty
249 				 * but not null.  Otherwise the pattern space
250 				 * will become null after the swap, which is
251 				 * an abnormal condition.
252 				 */
253 				if (hs == NULL)
254 					cspace(&HS, "", 0, REPLACE);
255 				tspace = PS;
256 				PS = HS;
257 				psanl = tspace.append_newline;
258 				HS = tspace;
259 				break;
260 			case 'y':
261 				if (pd || psl == 0)
262 					break;
263 				do_tr(cp->u.y);
264 				break;
265 			case ':':
266 			case '}':
267 				break;
268 			case '=':
269 				(void)fprintf(outfile, "%lu\n", linenum);
270 			}
271 			cp = cp->next;
272 		} /* for all cp */
273 
274 new:		if (!nflag && !pd)
275 			OUT();
276 		flush_appends();
277 	} /* for all lines */
278 }
279 
280 /*
281  * TRUE if the address passed matches the current program state
282  * (lastline, linenumber, ps).
283  */
284 #define	MATCH(a)							\
285 	((a)->type == AT_RE ? regexec_e((a)->u.r, ps, 0, 1, 0, psl) :	\
286 	    (a)->type == AT_LINE ? linenum == (a)->u.l : lastline())
287 
288 /*
289  * Return TRUE if the command applies to the current line.  Sets the start
290  * line for process ranges.  Interprets the non-select (``!'') flag.
291  */
292 static inline int
293 applies(struct s_command *cp)
294 {
295 	int r;
296 
297 	lastaddr = 0;
298 	if (cp->a1 == NULL && cp->a2 == NULL)
299 		r = 1;
300 	else if (cp->a2)
301 		if (cp->startline > 0) {
302                         switch (cp->a2->type) {
303                         case AT_RELLINE:
304                                 if (linenum - cp->startline <= cp->a2->u.l)
305                                         r = 1;
306                                 else {
307 				        cp->startline = 0;
308 				        r = 0;
309                                 }
310                                 break;
311                         default:
312                                 if (MATCH(cp->a2)) {
313                                         cp->startline = 0;
314                                         lastaddr = 1;
315                                         r = 1;
316                                 } else if (cp->a2->type == AT_LINE &&
317                                             linenum > cp->a2->u.l) {
318                                         /*
319                                          * We missed the 2nd address due to a
320                                          * branch, so just close the range and
321                                          * return false.
322                                          */
323                                         cp->startline = 0;
324                                         r = 0;
325                                 } else
326                                         r = 1;
327                         }
328 		} else if (cp->a1 && MATCH(cp->a1)) {
329 			/*
330 			 * If the second address is a number less than or
331 			 * equal to the line number first selected, only
332 			 * one line shall be selected.
333 			 *	-- POSIX 1003.2
334 			 * Likewise if the relative second line address is zero.
335 			 */
336 			if ((cp->a2->type == AT_LINE &&
337 			    linenum >= cp->a2->u.l) ||
338 			    (cp->a2->type == AT_RELLINE && cp->a2->u.l == 0))
339 				lastaddr = 1;
340 			else {
341 				cp->startline = linenum;
342 			}
343 			r = 1;
344 		} else
345 			r = 0;
346 	else
347 		r = MATCH(cp->a1);
348 	return (cp->nonsel ? ! r : r);
349 }
350 
351 /*
352  * Reset the sed processor to its initial state.
353  */
354 void
355 resetstate(void)
356 {
357 	struct s_command *cp;
358 
359 	/*
360 	 * Reset all in-range markers.
361 	 */
362 	for (cp = prog; cp; cp = cp->code == '{' ? cp->u.c : cp->next)
363 		if (cp->a2)
364 			cp->startline = 0;
365 
366 	/*
367 	 * Clear out the hold space.
368 	 */
369 	cspace(&HS, "", 0, REPLACE);
370 }
371 
372 /*
373  * substitute --
374  *	Do substitutions in the pattern space.  Currently, we build a
375  *	copy of the new pattern space in the substitute space structure
376  *	and then swap them.
377  */
378 static int
379 substitute(struct s_command *cp)
380 {
381 	SPACE tspace;
382 	regex_t *re;
383 	regoff_t slen;
384 	int lastempty, n;
385 	size_t le = 0;
386 	char *s;
387 
388 	s = ps;
389 	re = cp->u.s->re;
390 	if (re == NULL) {
391 		if (defpreg != NULL && cp->u.s->maxbref > defpreg->re_nsub) {
392 			linenum = cp->u.s->linenum;
393 			errx(1, "%lu: %s: \\%u not defined in the RE",
394 					linenum, fname, cp->u.s->maxbref);
395 		}
396 	}
397 	if (!regexec_e(re, ps, 0, 0, 0, psl))
398 		return (0);
399 
400 	SS.len = 0;				/* Clean substitute space. */
401 	slen = psl;
402 	n = cp->u.s->n;
403 	lastempty = 1;
404 
405 	do {
406 		/* Copy the leading retained string. */
407 		if (n <= 1 && (match[0].rm_so > le))
408 			cspace(&SS, s, match[0].rm_so - le, APPEND);
409 
410 		/* Skip zero-length matches right after other matches. */
411 		if (lastempty || (match[0].rm_so - le) ||
412 		    match[0].rm_so != match[0].rm_eo) {
413 			if (n <= 1) {
414 				/* Want this match: append replacement. */
415 				regsub(&SS, ps, cp->u.s->new);
416 				if (n == 1)
417 					n = -1;
418 			} else {
419 				/* Want a later match: append original. */
420 				if (match[0].rm_eo - le)
421 					cspace(&SS, s, match[0].rm_eo - le,
422 					    APPEND);
423 				n--;
424 			}
425 		}
426 
427 		/* Move past this match. */
428 		s = ps + match[0].rm_eo;
429 		slen = psl - match[0].rm_eo;
430 		le = match[0].rm_eo;
431 
432 		/*
433 		 * After a zero-length match, advance one byte,
434 		 * and at the end of the line, terminate.
435 		 */
436 		if (match[0].rm_so == match[0].rm_eo) {
437 			if (*s == '\0' || *s == '\n')
438 				slen = -1;
439 			else
440 				slen--;
441 			if (*s != '\0') {
442 			 	cspace(&SS, s++, 1, APPEND);
443 				le++;
444 			}
445 			lastempty = 1;
446 		} else
447 			lastempty = 0;
448 
449 	} while (n >= 0 && slen >= 0 &&
450 	    regexec_e(re, ps, REG_NOTBOL, 0, le, psl));
451 
452 	/* Did not find the requested number of matches. */
453 	if (n > 1)
454 		return (0);
455 
456 	/* Copy the trailing retained string. */
457 	if (slen > 0)
458 		cspace(&SS, s, slen, APPEND);
459 
460 	/*
461 	 * Swap the substitute space and the pattern space, and make sure
462 	 * that any leftover pointers into stdio memory get lost.
463 	 */
464 	tspace = PS;
465 	PS = SS;
466 	psanl = tspace.append_newline;
467 	SS = tspace;
468 	SS.space = SS.back;
469 
470 	/* Handle the 'p' flag. */
471 	if (cp->u.s->p)
472 		OUT();
473 
474 	/* Handle the 'w' flag. */
475 	if (cp->u.s->wfile && !pd) {
476 		if (cp->u.s->wfd == -1 && (cp->u.s->wfd = open(cp->u.s->wfile,
477 		    O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, DEFFILEMODE)) == -1)
478 			err(1, "%s", cp->u.s->wfile);
479 		if (write(cp->u.s->wfd, ps, psl) != (ssize_t)psl ||
480 		    write(cp->u.s->wfd, "\n", 1) != 1)
481 			err(1, "%s", cp->u.s->wfile);
482 	}
483 	return (1);
484 }
485 
486 /*
487  * do_tr --
488  *	Perform translation ('y' command) in the pattern space.
489  */
490 static void
491 do_tr(struct s_tr *y)
492 {
493 	SPACE tmp;
494 	char c, *p;
495 	size_t clen, left;
496 	int i;
497 
498 	if (MB_CUR_MAX == 1) {
499 		/*
500 		 * Single-byte encoding: perform in-place translation
501 		 * of the pattern space.
502 		 */
503 		for (p = ps; p < &ps[psl]; p++)
504 			*p = y->bytetab[(u_char)*p];
505 	} else {
506 		/*
507 		 * Multi-byte encoding: perform translation into the
508 		 * translation space, then swap the translation and
509 		 * pattern spaces.
510 		 */
511 		/* Clean translation space. */
512 		YS.len = 0;
513 		for (p = ps, left = psl; left > 0; p += clen, left -= clen) {
514 			if ((c = y->bytetab[(u_char)*p]) != '\0') {
515 				cspace(&YS, &c, 1, APPEND);
516 				clen = 1;
517 				continue;
518 			}
519 			for (i = 0; i < y->nmultis; i++)
520 				if (left >= y->multis[i].fromlen &&
521 				    memcmp(p, y->multis[i].from,
522 				    y->multis[i].fromlen) == 0)
523 					break;
524 			if (i < y->nmultis) {
525 				cspace(&YS, y->multis[i].to,
526 				    y->multis[i].tolen, APPEND);
527 				clen = y->multis[i].fromlen;
528 			} else {
529 				cspace(&YS, p, 1, APPEND);
530 				clen = 1;
531 			}
532 		}
533 		/* Swap the translation space and the pattern space. */
534 		tmp = PS;
535 		PS = YS;
536 		psanl = tmp.append_newline;
537 		YS = tmp;
538 		YS.space = YS.back;
539 	}
540 }
541 
542 /*
543  * Flush append requests.  Always called before reading a line,
544  * therefore it also resets the substitution done (sdone) flag.
545  */
546 static void
547 flush_appends(void)
548 {
549 	FILE *f;
550 	int count, i;
551 	char buf[8 * 1024];
552 
553 	for (i = 0; i < appendx; i++)
554 		switch (appends[i].type) {
555 		case AP_STRING:
556 			fwrite(appends[i].s, sizeof(char), appends[i].len,
557 			    outfile);
558 			break;
559 		case AP_FILE:
560 			/*
561 			 * Read files probably shouldn't be cached.  Since
562 			 * it's not an error to read a non-existent file,
563 			 * it's possible that another program is interacting
564 			 * with the sed script through the filesystem.  It
565 			 * would be truly bizarre, but possible.  It's probably
566 			 * not that big a performance win, anyhow.
567 			 */
568 			if ((f = fopen(appends[i].s, "r")) == NULL)
569 				break;
570 			while ((count = fread(buf, sizeof(char), sizeof(buf), f)))
571 				(void)fwrite(buf, sizeof(char), count, outfile);
572 			(void)fclose(f);
573 			break;
574 		}
575 	if (ferror(outfile))
576 		errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
577 	appendx = sdone = 0;
578 }
579 
580 static void
581 lputs(char *s, size_t len)
582 {
583 	static const char escapes[] = "\\\a\b\f\r\t\v";
584 	int c, col, width;
585 	const char *p;
586 	struct winsize win;
587 	static int termwidth = -1;
588 	size_t clen, i;
589 	wchar_t wc;
590 	mbstate_t mbs;
591 
592 	if (outfile != stdout)
593 		termwidth = 60;
594 	if (termwidth == -1) {
595 		if ((p = getenv("COLUMNS")) && *p != '\0')
596 			termwidth = atoi(p);
597 		else if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) == 0 &&
598 		    win.ws_col > 0)
599 			termwidth = win.ws_col;
600 		else
601 			termwidth = 60;
602 	}
603 	if (termwidth <= 0)
604 		termwidth = 1;
605 
606 	memset(&mbs, 0, sizeof(mbs));
607 	col = 0;
608 	while (len != 0) {
609 		clen = mbrtowc(&wc, s, len, &mbs);
610 		if (clen == 0)
611 			clen = 1;
612 		if (clen == (size_t)-1 || clen == (size_t)-2) {
613 			wc = (unsigned char)*s;
614 			clen = 1;
615 			memset(&mbs, 0, sizeof(mbs));
616 		}
617 		if (wc == '\n') {
618 			if (col + 1 >= termwidth)
619 				fprintf(outfile, "\\\n");
620 			fputc('$', outfile);
621 			fputc('\n', outfile);
622 			col = 0;
623 		} else if (iswprint(wc)) {
624 			width = wcwidth(wc);
625 			if (col + width >= termwidth) {
626 				fprintf(outfile, "\\\n");
627 				col = 0;
628 			}
629 			fwrite(s, 1, clen, outfile);
630 			col += width;
631 		} else if (wc != L'\0' && (c = wctob(wc)) != EOF &&
632 		    (p = strchr(escapes, c)) != NULL) {
633 			if (col + 2 >= termwidth) {
634 				fprintf(outfile, "\\\n");
635 				col = 0;
636 			}
637 			fprintf(outfile, "\\%c", "\\abfrtv"[p - escapes]);
638 			col += 2;
639 		} else {
640 			if (col + 4 * clen >= (unsigned)termwidth) {
641 				fprintf(outfile, "\\\n");
642 				col = 0;
643 			}
644 			for (i = 0; i < clen; i++)
645 				fprintf(outfile, "\\%03o",
646 				    (int)(unsigned char)s[i]);
647 			col += 4 * clen;
648 		}
649 		s += clen;
650 		len -= clen;
651 	}
652 	if (col + 1 >= termwidth)
653 		fprintf(outfile, "\\\n");
654 	(void)fputc('$', outfile);
655 	(void)fputc('\n', outfile);
656 	if (ferror(outfile))
657 		errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
658 }
659 
660 static int
661 regexec_e(regex_t *preg, const char *string, int eflags, int nomatch,
662 	size_t start, size_t stop)
663 {
664 	int eval;
665 
666 	if (preg == NULL) {
667 		if (defpreg == NULL)
668 			errx(1, "first RE may not be empty");
669 	} else
670 		defpreg = preg;
671 
672 	/* Set anchors */
673 	match[0].rm_so = start;
674 	match[0].rm_eo = stop;
675 
676 	eval = regexec(defpreg, string,
677 	    nomatch ? 0 : maxnsub + 1, match, eflags | REG_STARTEND);
678 	switch(eval) {
679 	case 0:
680 		return (1);
681 	case REG_NOMATCH:
682 		return (0);
683 	}
684 	errx(1, "RE error: %s", strregerror(eval, defpreg));
685 	/* NOTREACHED */
686 }
687 
688 /*
689  * regsub - perform substitutions after a regexp match
690  * Based on a routine by Henry Spencer
691  */
692 static void
693 regsub(SPACE *sp, char *string, char *src)
694 {
695 	int len, no;
696 	char c, *dst;
697 
698 #define	NEEDSP(reqlen)							\
699 	/* XXX What is the +1 for? */					\
700 	if (sp->len + (reqlen) + 1 >= sp->blen) {			\
701 		sp->blen += (reqlen) + 1024;				\
702 		if ((sp->space = sp->back = realloc(sp->back, sp->blen)) \
703 		    == NULL)						\
704 			err(1, "realloc");				\
705 		dst = sp->space + sp->len;				\
706 	}
707 
708 	dst = sp->space + sp->len;
709 	while ((c = *src++) != '\0') {
710 		if (c == '&')
711 			no = 0;
712 		else if (c == '\\' && isdigit((unsigned char)*src))
713 			no = *src++ - '0';
714 		else
715 			no = -1;
716 		if (no < 0) {		/* Ordinary character. */
717 			if (c == '\\' && (*src == '\\' || *src == '&'))
718 				c = *src++;
719 			NEEDSP(1);
720 			*dst++ = c;
721 			++sp->len;
722 		} else if (match[no].rm_so != -1 && match[no].rm_eo != -1) {
723 			len = match[no].rm_eo - match[no].rm_so;
724 			NEEDSP(len);
725 			memmove(dst, string + match[no].rm_so, len);
726 			dst += len;
727 			sp->len += len;
728 		}
729 	}
730 	NEEDSP(1);
731 	*dst = '\0';
732 }
733 
734 /*
735  * cspace --
736  *	Concatenate space: append the source space to the destination space,
737  *	allocating new space as necessary.
738  */
739 void
740 cspace(SPACE *sp, const char *p, size_t len, enum e_spflag spflag)
741 {
742 	size_t tlen;
743 
744 	/* Make sure SPACE has enough memory and ramp up quickly. */
745 	tlen = sp->len + len + 1;
746 	if (tlen > sp->blen) {
747 		sp->blen = tlen + 1024;
748 		if ((sp->space = sp->back = realloc(sp->back, sp->blen)) ==
749 		    NULL)
750 			err(1, "realloc");
751 	}
752 
753 	if (spflag == REPLACE)
754 		sp->len = 0;
755 
756 	memmove(sp->space + sp->len, p, len);
757 
758 	sp->space[sp->len += len] = '\0';
759 }
760 
761 /*
762  * Close all cached opened files and report any errors
763  */
764 void
765 cfclose(struct s_command *cp, struct s_command *end)
766 {
767 
768 	for (; cp != end; cp = cp->next)
769 		switch(cp->code) {
770 		case 's':
771 			if (cp->u.s->wfd != -1 && close(cp->u.s->wfd))
772 				err(1, "%s", cp->u.s->wfile);
773 			cp->u.s->wfd = -1;
774 			break;
775 		case 'w':
776 			if (cp->u.fd != -1 && close(cp->u.fd))
777 				err(1, "%s", cp->t);
778 			cp->u.fd = -1;
779 			break;
780 		case '{':
781 			cfclose(cp->u.c, cp->next);
782 			break;
783 		}
784 }
785