usr.bin/sed/process.c

   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 hs              HS.space
  67 #define hsl             HS.len
  68
  69 static inline int        applies(struct s_command *);
  70 static void              do_tr(struct s_tr *);
  71 static void              flush_appends(void);
  72 static void              lputs(char *, size_t);
  73 static int               regexec_e(regex_t *, const char *, int, int, size_t,
  74                              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 unsigned int appendx;    /* Index into appends array. */
  80 unsigned 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 {fwrite(ps, 1, psl, outfile); fputc('\n', outfile);} while (0)
  90
  91 void
  92 process(void)
  93 {
  94         struct s_command *cp;
  95         SPACE tspace;
  96         size_t oldpsl = 0;
  97         char *p;
  98
  99         p = NULL;
 100
 101         for (linenum = 0; mf_fgets(&PS, REPLACE);) {
 102                 pd = 0;
 103 top:
 104                 cp = prog;
 105 redirect:
 106                 while (cp != NULL) {
 107                         if (!applies(cp)) {
 108                                 cp = cp->next;
 109                                 continue;
 110                         }
 111                         switch (cp->code) {
 112                         case '{':
 113                                 cp = cp->u.c;
 114                                 goto redirect;
 115                         case 'a':
 116                                 if (appendx >= appendnum)
 117                                         if ((appends = realloc(appends,
 118                                             sizeof(struct s_appends) *
 119                                             (appendnum *= 2))) == NULL)
 120                                                 err(1, "realloc");
 121                                 appends[appendx].type = AP_STRING;
 122                                 appends[appendx].s = cp->t;
 123                                 appends[appendx].len = strlen(cp->t);
 124                                 appendx++;
 125                                 break;
 126                         case 'b':
 127                                 cp = cp->u.c;
 128                                 goto redirect;
 129                         case 'c':
 130                                 pd = 1;
 131                                 psl = 0;
 132                                 if (cp->a2 == NULL || lastaddr || lastline())
 133                                         (void)fprintf(outfile, "%s", cp->t);
 134                                 break;
 135                         case 'd':
 136                                 pd = 1;
 137                                 goto new;
 138                         case 'D':
 139                                 if (pd)
 140                                         goto new;
 141                                 if (psl == 0 ||
 142                                     (p = memchr(ps, '\n', psl)) == NULL) {
 143                                         pd = 1;
 144                                         goto new;
 145                                 } else {
 146                                         psl -= (p + 1) - ps;
 147                                         memmove(ps, p + 1, psl);
 148                                         goto top;
 149                                 }
 150                         case 'g':
 151                                 cspace(&PS, hs, hsl, REPLACE);
 152                                 break;
 153                         case 'G':
 154                                 cspace(&PS, "\n", 1, APPEND);
 155                                 cspace(&PS, hs, hsl, APPEND);
 156                                 break;
 157                         case 'h':
 158                                 cspace(&HS, ps, psl, REPLACE);
 159                                 break;
 160                         case 'H':
 161                                 cspace(&HS, "\n", 1, APPEND);
 162                                 cspace(&HS, ps, psl, APPEND);
 163                                 break;
 164                         case 'i':
 165                                 (void)fprintf(outfile, "%s", cp->t);
 166                                 break;
 167                         case 'l':
 168                                 lputs(ps, psl);
 169                                 break;
 170                         case 'n':
 171                                 if (!nflag && !pd)
 172                                         OUT();
 173                                 flush_appends();
 174                                 if (!mf_fgets(&PS, REPLACE))
 175                                         exit(0);
 176                                 pd = 0;
 177                                 break;
 178                         case 'N':
 179                                 flush_appends();
 180                                 cspace(&PS, "\n", 1, APPEND);
 181                                 if (!mf_fgets(&PS, APPEND))
 182                                         exit(0);
 183                                 break;
 184                         case 'p':
 185                                 if (pd)
 186                                         break;
 187                                 OUT();
 188                                 break;
 189                         case 'P':
 190                                 if (pd)
 191                                         break;
 192                                 if ((p = memchr(ps, '\n', psl)) != NULL) {
 193                                         oldpsl = psl;
 194                                         psl = p - ps;
 195                                 }
 196                                 OUT();
 197                                 if (p != NULL)
 198                                         psl = oldpsl;
 199                                 break;
 200                         case 'q':
 201                                 if (!nflag && !pd)
 202                                         OUT();
 203                                 flush_appends();
 204                                 exit(0);
 205                         case 'r':
 206                                 if (appendx >= appendnum)
 207                                         if ((appends = realloc(appends,
 208                                             sizeof(struct s_appends) *
 209                                             (appendnum *= 2))) == NULL)
 210                                                 err(1, "realloc");
 211                                 appends[appendx].type = AP_FILE;
 212                                 appends[appendx].s = cp->t;
 213                                 appends[appendx].len = strlen(cp->t);
 214                                 appendx++;
 215                                 break;
 216                         case 's':
 217                                 sdone |= substitute(cp);
 218                                 break;
 219                         case 't':
 220                                 if (sdone) {
 221                                         sdone = 0;
 222                                         cp = cp->u.c;
 223                                         goto redirect;
 224                                 }
 225                                 break;
 226                         case 'w':
 227                                 if (pd)
 228                                         break;
 229                                 if (cp->u.fd == -1 && (cp->u.fd = open(cp->t,
 230                                     O_WRONLY|O_APPEND|O_CREAT|O_TRUNC,
 231                                     DEFFILEMODE)) == -1)
 232                                         err(1, "%s", cp->t);
 233                                 if (write(cp->u.fd, ps, psl) != (ssize_t)psl ||
 234                                     write(cp->u.fd, "\n", 1) != 1)
 235                                         err(1, "%s", cp->t);
 236                                 break;
 237                         case 'x':
 238                                 /*
 239                                  * If the hold space is null, make it empty
 240                                  * but not null.  Otherwise the pattern space
 241                                  * will become null after the swap, which is
 242                                  * an abnormal condition.
 243                                  */
 244                                 if (hs == NULL)
 245                                         cspace(&HS, "", 0, REPLACE);
 246                                 tspace = PS;
 247                                 PS = HS;
 248                                 HS = tspace;
 249                                 break;
 250                         case 'y':
 251                                 if (pd || psl == 0)
 252                                         break;
 253                                 do_tr(cp->u.y);
 254                                 break;
 255                         case ':':
 256                         case '}':
 257                                 break;
 258                         case '=':
 259                                 (void)fprintf(outfile, "%lu\n", linenum);
 260                         }
 261                         cp = cp->next;
 262                 } /* for all cp */
 263
 264 new:            if (!nflag && !pd)
 265                         OUT();
 266                 flush_appends();
 267         } /* for all lines */
 268 }
 269
 270 /*
 271  * TRUE if the address passed matches the current program state
 272  * (lastline, linenumber, ps).
 273  */
 274 #define MATCH(a)                                                        \
 275         ((a)->type == AT_RE ? regexec_e((a)->u.r, ps, 0, 1, 0, psl) :   \
 276             (a)->type == AT_LINE ? linenum == (a)->u.l : lastline())
 277
 278 /*
 279  * Return TRUE if the command applies to the current line.  Sets the start
 280  * line for process ranges.  Interprets the non-select (``!'') flag.
 281  */
 282 static inline int
 283 applies(struct s_command *cp)
 284 {
 285         int r;
 286
 287         lastaddr = 0;
 288         if (cp->a1 == NULL && cp->a2 == NULL)
 289                 r = 1;
 290         else if (cp->a2)
 291                 if (cp->startline > 0) {
 292                         switch (cp->a2->type) {
 293                         case AT_RELLINE:
 294                                 if (linenum - cp->startline <= cp->a2->u.l)
 295                                         r = 1;
 296                                 else {
 297                                         cp->startline = 0;
 298                                         r = 0;
 299                                 }
 300                                 break;
 301                         default:
 302                                 if (MATCH(cp->a2)) {
 303                                         cp->startline = 0;
 304                                         lastaddr = 1;
 305                                         r = 1;
 306                                 } else if (cp->a2->type == AT_LINE &&
 307                                             linenum > cp->a2->u.l) {
 308                                         /*
 309                                          * We missed the 2nd address due to a
 310                                          * branch, so just close the range and
 311                                          * return false.
 312                                          */
 313                                         cp->startline = 0;
 314                                         r = 0;
 315                                 } else
 316                                         r = 1;
 317                         }
 318                 } else if (cp->a1 && MATCH(cp->a1)) {
 319                         /*
 320                          * If the second address is a number less than or
 321                          * equal to the line number first selected, only
 322                          * one line shall be selected.
 323                          *      -- POSIX 1003.2
 324                          * Likewise if the relative second line address is zero.
 325                          */
 326                         if ((cp->a2->type == AT_LINE &&
 327                             linenum >= cp->a2->u.l) ||
 328                             (cp->a2->type == AT_RELLINE && cp->a2->u.l == 0))
 329                                 lastaddr = 1;
 330                         else {
 331                                 cp->startline = linenum;
 332                         }
 333                         r = 1;
 334                 } else
 335                         r = 0;
 336         else
 337                 r = MATCH(cp->a1);
 338         return (cp->nonsel ? ! r : r);
 339 }
 340
 341 /*
 342  * Reset the sed processor to its initial state.
 343  */
 344 void
 345 resetstate(void)
 346 {
 347         struct s_command *cp;
 348
 349         /*
 350          * Reset all in-range markers.
 351          */
 352         for (cp = prog; cp; cp = cp->code == '{' ? cp->u.c : cp->next)
 353                 if (cp->a2)
 354                         cp->startline = 0;
 355
 356         /*
 357          * Clear out the hold space.
 358          */
 359         cspace(&HS, "", 0, REPLACE);
 360 }
 361
 362 /*
 363  * substitute --
 364  *      Do substitutions in the pattern space.  Currently, we build a
 365  *      copy of the new pattern space in the substitute space structure
 366  *      and then swap them.
 367  */
 368 static int
 369 substitute(struct s_command *cp)
 370 {
 371         SPACE tspace;
 372         regex_t *re;
 373         regoff_t slen;
 374         int lastempty, n;
 375         regoff_t le = 0;
 376         char *s;
 377
 378         s = ps;
 379         re = cp->u.s->re;
 380         if (re == NULL) {
 381                 if (defpreg != NULL && cp->u.s->maxbref > defpreg->re_nsub) {
 382                         linenum = cp->u.s->linenum;
 383                         errx(1, "%lu: %s: \\%u not defined in the RE",
 384                                         linenum, fname, cp->u.s->maxbref);
 385                 }
 386         }
 387         if (!regexec_e(re, ps, 0, 0, 0, psl))
 388                 return (0);
 389
 390         SS.len = 0;                             /* Clean substitute space. */
 391         slen = psl;
 392         n = cp->u.s->n;
 393         lastempty = 1;
 394
 395         do {
 396                 /* Copy the leading retained string. */
 397                 if (n <= 1 && (match[0].rm_so > le))
 398                         cspace(&SS, s, match[0].rm_so - le, APPEND);
 399
 400                 /* Skip zero-length matches right after other matches. */
 401                 if (lastempty || (match[0].rm_so - le) ||
 402                     match[0].rm_so != match[0].rm_eo) {
 403                         if (n <= 1) {
 404                                 /* Want this match: append replacement. */
 405                                 regsub(&SS, ps, cp->u.s->new);
 406                                 if (n == 1)
 407                                         n = -1;
 408                         } else {
 409                                 /* Want a later match: append original. */
 410                                 if (match[0].rm_eo - le)
 411                                         cspace(&SS, s, match[0].rm_eo - le,
 412                                             APPEND);
 413                                 n--;
 414                         }
 415                 }
 416
 417                 /* Move past this match. */
 418                 s = ps + match[0].rm_eo;
 419                 slen = psl - match[0].rm_eo;
 420                 le = match[0].rm_eo;
 421
 422                 /*
 423                  * After a zero-length match, advance one byte,
 424                  * and at the end of the line, terminate.
 425                  */
 426                 if (match[0].rm_so == match[0].rm_eo) {
 427                         if (*s == '\0' || *s == '\n')
 428                                 slen = -1;
 429                         else
 430                                 slen--;
 431                         if (*s != '\0') {
 432                                 cspace(&SS, s++, 1, APPEND);
 433                                 le++;
 434                         }
 435                         lastempty = 1;
 436                 } else
 437                         lastempty = 0;
 438
 439         } while (n >= 0 && slen >= 0 &&
 440             regexec_e(re, ps, REG_NOTBOL, 0, le, psl));
 441
 442         /* Did not find the requested number of matches. */
 443         if (n > 0)
 444                 return (0);
 445
 446         /* Copy the trailing retained string. */
 447         if (slen > 0)
 448                 cspace(&SS, s, slen, APPEND);
 449
 450         /*
 451          * Swap the substitute space and the pattern space, and make sure
 452          * that any leftover pointers into stdio memory get lost.
 453          */
 454         tspace = PS;
 455         PS = SS;
 456         SS = tspace;
 457         SS.space = SS.back;
 458
 459         /* Handle the 'p' flag. */
 460         if (cp->u.s->p)
 461                 OUT();
 462
 463         /* Handle the 'w' flag. */
 464         if (cp->u.s->wfile && !pd) {
 465                 if (cp->u.s->wfd == -1 && (cp->u.s->wfd = open(cp->u.s->wfile,
 466                     O_WRONLY|O_APPEND|O_CREAT|O_TRUNC, DEFFILEMODE)) == -1)
 467                         err(1, "%s", cp->u.s->wfile);
 468                 if (write(cp->u.s->wfd, ps, psl) != (ssize_t)psl ||
 469                     write(cp->u.s->wfd, "\n", 1) != 1)
 470                         err(1, "%s", cp->u.s->wfile);
 471         }
 472         return (1);
 473 }
 474
 475 /*
 476  * do_tr --
 477  *      Perform translation ('y' command) in the pattern space.
 478  */
 479 static void
 480 do_tr(struct s_tr *y)
 481 {
 482         SPACE tmp;
 483         char c, *p;
 484         size_t clen, left;
 485         int i;
 486
 487         if (MB_CUR_MAX == 1) {
 488                 /*
 489                  * Single-byte encoding: perform in-place translation
 490                  * of the pattern space.
 491                  */
 492                 for (p = ps; p < &ps[psl]; p++)
 493                         *p = y->bytetab[(u_char)*p];
 494         } else {
 495                 /*
 496                  * Multi-byte encoding: perform translation into the
 497                  * translation space, then swap the translation and
 498                  * pattern spaces.
 499                  */
 500                 /* Clean translation space. */
 501                 YS.len = 0;
 502                 for (p = ps, left = psl; left > 0; p += clen, left -= clen) {
 503                         if ((c = y->bytetab[(u_char)*p]) != '\0') {
 504                                 cspace(&YS, &c, 1, APPEND);
 505                                 clen = 1;
 506                                 continue;
 507                         }
 508                         for (i = 0; i < y->nmultis; i++)
 509                                 if (left >= y->multis[i].fromlen &&
 510                                     memcmp(p, y->multis[i].from,
 511                                     y->multis[i].fromlen) == 0)
 512                                         break;
 513                         if (i < y->nmultis) {
 514                                 cspace(&YS, y->multis[i].to,
 515                                     y->multis[i].tolen, APPEND);
 516                                 clen = y->multis[i].fromlen;
 517                         } else {
 518                                 cspace(&YS, p, 1, APPEND);
 519                                 clen = 1;
 520                         }
 521                 }
 522                 /* Swap the translation space and the pattern space. */
 523                 tmp = PS;
 524                 PS = YS;
 525                 YS = tmp;
 526                 YS.space = YS.back;
 527         }
 528 }
 529
 530 /*
 531  * Flush append requests.  Always called before reading a line,
 532  * therefore it also resets the substitution done (sdone) flag.
 533  */
 534 static void
 535 flush_appends(void)
 536 {
 537         FILE *f;
 538         unsigned int count, idx;
 539         char buf[8 * 1024];
 540
 541         for (idx = 0; idx < appendx; idx++)
 542                 switch (appends[idx].type) {
 543                 case AP_STRING:
 544                         fwrite(appends[idx].s, sizeof(char), appends[idx].len,
 545                             outfile);
 546                         break;
 547                 case AP_FILE:
 548                         /*
 549                          * Read files probably shouldn't be cached.  Since
 550                          * it's not an error to read a non-existent file,
 551                          * it's possible that another program is interacting
 552                          * with the sed script through the filesystem.  It
 553                          * would be truly bizarre, but possible.  It's probably
 554                          * not that big a performance win, anyhow.
 555                          */
 556                         if ((f = fopen(appends[idx].s, "r")) == NULL)
 557                                 break;
 558                         while ((count = fread(buf, sizeof(char), sizeof(buf), f)))
 559                                 (void)fwrite(buf, sizeof(char), count, outfile);
 560                         (void)fclose(f);
 561                         break;
 562                 }
 563         if (ferror(outfile))
 564                 errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
 565         appendx = sdone = 0;
 566 }
 567
 568 static void
 569 lputs(char *s, size_t len)
 570 {
 571         static const char escapes[] = "\\\a\b\f\r\t\v";
 572         int c, col, width;
 573         const char *p;
 574         struct winsize win;
 575         static int termwidth = -1;
 576         size_t clen, i;
 577         wchar_t wc;
 578         mbstate_t mbs;
 579
 580         if (outfile != stdout)
 581                 termwidth = 60;
 582         if (termwidth == -1) {
 583                 if ((p = getenv("COLUMNS")) && *p != '\0')
 584                         termwidth = atoi(p);
 585                 else if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &win) == 0 &&
 586                     win.ws_col > 0)
 587                         termwidth = win.ws_col;
 588                 else
 589                         termwidth = 60;
 590         }
 591         if (termwidth <= 0)
 592                 termwidth = 1;
 593
 594         memset(&mbs, 0, sizeof(mbs));
 595         col = 0;
 596         while (len != 0) {
 597                 clen = mbrtowc(&wc, s, len, &mbs);
 598                 if (clen == 0)
 599                         clen = 1;
 600                 if (clen == (size_t)-1 || clen == (size_t)-2) {
 601                         wc = (unsigned char)*s;
 602                         clen = 1;
 603                         memset(&mbs, 0, sizeof(mbs));
 604                 }
 605                 if (wc == '\n') {
 606                         if (col + 1 >= termwidth)
 607                                 fprintf(outfile, "\\\n");
 608                         fputc('$', outfile);
 609                         fputc('\n', outfile);
 610                         col = 0;
 611                 } else if (iswprint(wc)) {
 612                         width = wcwidth(wc);
 613                         if (col + width >= termwidth) {
 614                                 fprintf(outfile, "\\\n");
 615                                 col = 0;
 616                         }
 617                         fwrite(s, 1, clen, outfile);
 618                         col += width;
 619                 } else if (wc != L'\0' && (c = wctob(wc)) != EOF &&
 620                     (p = strchr(escapes, c)) != NULL) {
 621                         if (col + 2 >= termwidth) {
 622                                 fprintf(outfile, "\\\n");
 623                                 col = 0;
 624                         }
 625                         fprintf(outfile, "\\%c", "\\abfrtv"[p - escapes]);
 626                         col += 2;
 627                 } else {
 628                         if (col + 4 * clen >= (unsigned)termwidth) {
 629                                 fprintf(outfile, "\\\n");
 630                                 col = 0;
 631                         }
 632                         for (i = 0; i < clen; i++)
 633                                 fprintf(outfile, "\\%03o",
 634                                     (int)(unsigned char)s[i]);
 635                         col += 4 * clen;
 636                 }
 637                 s += clen;
 638                 len -= clen;
 639         }
 640         if (col + 1 >= termwidth)
 641                 fprintf(outfile, "\\\n");
 642         (void)fputc('$', outfile);
 643         (void)fputc('\n', outfile);
 644         if (ferror(outfile))
 645                 errx(1, "%s: %s", outfname, strerror(errno ? errno : EIO));
 646 }
 647
 648 static int
 649 regexec_e(regex_t *preg, const char *string, int eflags, int nomatch,
 650         size_t start, size_t stop)
 651 {
 652         int eval;
 653
 654         if (preg == NULL) {
 655                 if (defpreg == NULL)
 656                         errx(1, "first RE may not be empty");
 657         } else
 658                 defpreg = preg;
 659
 660         /* Set anchors */
 661         match[0].rm_so = start;
 662         match[0].rm_eo = stop;
 663
 664         eval = regexec(defpreg, string,
 665             nomatch ? 0 : maxnsub + 1, match, eflags | REG_STARTEND);
 666         switch(eval) {
 667         case 0:
 668                 return (1);
 669         case REG_NOMATCH:
 670                 return (0);
 671         }
 672         errx(1, "RE error: %s", strregerror(eval, defpreg));
 673         /* NOTREACHED */
 674 }
 675
 676 /*
 677  * regsub - perform substitutions after a regexp match
 678  * Based on a routine by Henry Spencer
 679  */
 680 static void
 681 regsub(SPACE *sp, char *string, char *src)
 682 {
 683         int len, no;
 684         char c, *dst;
 685
 686 #define NEEDSP(reqlen)                                                  \
 687         /* XXX What is the +1 for? */                                   \
 688         if (sp->len + (reqlen) + 1 >= sp->blen) {                       \
 689                 sp->blen += (reqlen) + 1024;                            \
 690                 if ((sp->space = sp->back = realloc(sp->back, sp->blen)) \
 691                     == NULL)                                            \
 692                         err(1, "realloc");                              \
 693                 dst = sp->space + sp->len;                              \
 694         }
 695
 696         dst = sp->space + sp->len;
 697         while ((c = *src++) != '\0') {
 698                 if (c == '&')
 699                         no = 0;
 700                 else if (c == '\\' && isdigit((unsigned char)*src))
 701                         no = *src++ - '0';
 702                 else
 703                         no = -1;
 704                 if (no < 0) {           /* Ordinary character. */
 705                         if (c == '\\' && (*src == '\\' || *src == '&'))
 706                                 c = *src++;
 707                         NEEDSP(1);
 708                         *dst++ = c;
 709                         ++sp->len;
 710                 } else if (match[no].rm_so != -1 && match[no].rm_eo != -1) {
 711                         len = match[no].rm_eo - match[no].rm_so;
 712                         NEEDSP(len);
 713                         memmove(dst, string + match[no].rm_so, len);
 714                         dst += len;
 715                         sp->len += len;
 716                 }
 717         }
 718         NEEDSP(1);
 719         *dst = '\0';
 720 }
 721
 722 /*
 723  * cspace --
 724  *      Concatenate space: append the source space to the destination space,
 725  *      allocating new space as necessary.
 726  */
 727 void
 728 cspace(SPACE *sp, const char *p, size_t len, enum e_spflag spflag)
 729 {
 730         size_t tlen;
 731
 732         /* Make sure SPACE has enough memory and ramp up quickly. */
 733         tlen = sp->len + len + 1;
 734         if (tlen > sp->blen) {
 735                 sp->blen = tlen + 1024;
 736                 if ((sp->space = sp->back = realloc(sp->back, sp->blen)) ==
 737                     NULL)
 738                         err(1, "realloc");
 739         }
 740
 741         if (spflag == REPLACE)
 742                 sp->len = 0;
 743
 744         memmove(sp->space + sp->len, p, len);
 745
 746         sp->space[sp->len += len] = '\0';
 747 }
 748
 749 /*
 750  * Close all cached opened files and report any errors
 751  */
 752 void
 753 cfclose(struct s_command *cp, struct s_command *end)
 754 {
 755
 756         for (; cp != end; cp = cp->next)
 757                 switch(cp->code) {
 758                 case 's':
 759                         if (cp->u.s->wfd != -1 && close(cp->u.s->wfd))
 760                                 err(1, "%s", cp->u.s->wfile);
 761                         cp->u.s->wfd = -1;
 762                         break;
 763                 case 'w':
 764                         if (cp->u.fd != -1 && close(cp->u.fd))
 765                                 err(1, "%s", cp->t);
 766                         cp->u.fd = -1;
 767                         break;
 768                 case '{':
 769                         cfclose(cp->u.c, cp->next);
 770                         break;
 771                 }
 772 }