1 /* $OpenBSD: fmt.c,v 1.16 2000/06/25 15:35:42 pjanzen Exp $ */ 2 3 /* Sensible version of fmt 4 * 5 * Syntax: fmt [ options ] [ goal [ max ] ] [ filename ... ] 6 * 7 * Since the documentation for the original fmt is so poor, here 8 * is an accurate description of what this one does. It's usually 9 * the same. The *mechanism* used may differ from that suggested 10 * here. Note that we are *not* entirely compatible with fmt, 11 * because fmt gets so many things wrong. 12 * 13 * 1. Tabs are expanded, assuming 8-space tab stops. 14 * If the `-t <n>' option is given, we assume <n>-space 15 * tab stops instead. 16 * Trailing blanks are removed from all lines. 17 * x\b == nothing, for any x other than \b. 18 * Other control characters are simply stripped. This 19 * includes \r. 20 * 2. Each line is split into leading whitespace and 21 * everything else. Maximal consecutive sequences of 22 * lines with the same leading whitespace are considered 23 * to form paragraphs, except that a blank line is always 24 * a paragraph to itself. 25 * If the `-p' option is given then the first line of a 26 * paragraph is permitted to have indentation different 27 * from that of the other lines. 28 * If the `-m' option is given then a line that looks 29 * like a mail message header, if it is not immediately 30 * preceded by a non-blank non-message-header line, is 31 * taken to start a new paragraph, which also contains 32 * any subsequent lines with non-empty leading whitespace. 33 * Unless the `-n' option is given, lines beginning with 34 * a . (dot) are not formatted. 35 * 3. The "everything else" is split into words; a word 36 * includes its trailing whitespace, and a word at the 37 * end of a line is deemed to be followed by a single 38 * space, or two spaces if it ends with a sentence-end 39 * character. (See the `-d' option for how to change that.) 40 * If the `-s' option has been given, then a word's trailing 41 * whitespace is replaced by what it would have had if it 42 * had occurred at end of line. 43 * 4. Each paragraph is sent to standard output as follows. 44 * We output the leading whitespace, and then enough words 45 * to make the line length as near as possible to the goal 46 * without exceeding the maximum. (If a single word would 47 * exceed the maximum, we output that anyway.) Of course 48 * the trailing whitespace of the last word is ignored. 49 * We then emit a newline and start again if there are any 50 * words left. 51 * Note that for a blank line this translates as "We emit 52 * a newline". 53 * If the `-l <n>' option is given, then leading whitespace 54 * is modified slightly: <n> spaces are replaced by a tab. 55 * Indented paragraphs (see above under `-p') make matters 56 * more complicated than this suggests. Actually every paragraph 57 * has two `leading whitespace' values; the value for the first 58 * line, and the value for the most recent line. (While processing 59 * the first line, the two are equal. When `-p' has not been 60 * given, they are always equal.) The leading whitespace 61 * actually output is that of the first line (for the first 62 * line of *output*) or that of the most recent line (for 63 * all other lines of output). 64 * When `-m' has been given, message header paragraphs are 65 * taken as having first-leading-whitespace empty and 66 * subsequent-leading-whitespace two spaces. 67 * 68 * Multiple input files are formatted one at a time, so that a file 69 * never ends in the middle of a line. 70 * 71 * There's an alternative mode of operation, invoked by giving 72 * the `-c' option. In that case we just center every line, 73 * and most of the other options are ignored. This should 74 * really be in a separate program, but we must stay compatible 75 * with old `fmt'. 76 * 77 * QUERY: Should `-m' also try to do the right thing with quoted text? 78 * QUERY: `-b' to treat backslashed whitespace as old `fmt' does? 79 * QUERY: Option meaning `never join lines'? 80 * QUERY: Option meaning `split in mid-word to avoid overlong lines'? 81 * (Those last two might not be useful, since we have `fold'.) 82 * 83 * Differences from old `fmt': 84 * 85 * - We have many more options. Options that aren't understood 86 * generate a lengthy usage message, rather than being 87 * treated as filenames. 88 * - Even with `-m', our handling of message headers is 89 * significantly different. (And much better.) 90 * - We don't treat `\ ' as non-word-breaking. 91 * - Downward changes of indentation start new paragraphs 92 * for us, as well as upward. (I think old `fmt' behaves 93 * in the way it does in order to allow indented paragraphs, 94 * but this is a broken way of making indented paragraphs 95 * behave right.) 96 * - Given the choice of going over or under |goal_length| 97 * by the same amount, we go over; old `fmt' goes under. 98 * - We treat `?' as ending a sentence, and not `:'. Old `fmt' 99 * does the reverse. 100 * - We return approved return codes. Old `fmt' returns 101 * 1 for some errors, and *the number of unopenable files* 102 * when that was all that went wrong. 103 * - We have fewer crashes and more helpful error messages. 104 * - We don't turn spaces into tabs at starts of lines unless 105 * specifically requested. 106 * - New `fmt' is somewhat smaller and slightly faster than 107 * old `fmt'. 108 * 109 * Bugs: 110 * 111 * None known. There probably are some, though. 112 * 113 * Portability: 114 * 115 * I believe this code to be pretty portable. It does require 116 * that you have `getopt'. If you need to include "getopt.h" 117 * for this (e.g., if your system didn't come with `getopt' 118 * and you installed it yourself) then you should arrange for 119 * NEED_getopt_h to be #defined. 120 * 121 * Everything here should work OK even on nasty 16-bit 122 * machines and nice 64-bit ones. However, it's only really 123 * been tested on my FreeBSD machine. Your mileage may vary. 124 * 125 * $FreeBSD: head/usr.bin/fmt/fmt.c 200462 2009-12-13 03:14:06Z delphij $ 126 */ 127 128 /* Copyright (c) 1997 Gareth McCaughan. All rights reserved. 129 * 130 * Redistribution and use of this code, in source or binary forms, 131 * with or without modification, are permitted subject to the following 132 * conditions: 133 * 134 * - Redistribution of source code must retain the above copyright 135 * notice, this list of conditions and the following disclaimer. 136 * 137 * - If you distribute modified source code it must also include 138 * a notice saying that it has been modified, and giving a brief 139 * description of what changes have been made. 140 * 141 * Disclaimer: I am not responsible for the results of using this code. 142 * If it formats your hard disc, sends obscene messages to 143 * your boss and kills your children then that's your problem 144 * not mine. I give absolutely no warranty of any sort as to 145 * what the program will do, and absolutely refuse to be held 146 * liable for any consequences of your using it. 147 * Thank you. Have a nice day. 148 */ 149 150 /* RCS change log: 151 * Revision 1.5 1998/03/02 18:02:21 gjm11 152 * Minor changes for portability. 153 * 154 * Revision 1.4 1997/10/01 11:51:28 gjm11 155 * Repair broken indented-paragraph handling. 156 * Add mail message header stuff. 157 * Improve comments and layout. 158 * Make usable with non-BSD systems. 159 * Add revision display to usage message. 160 * 161 * Revision 1.3 1997/09/30 16:24:47 gjm11 162 * Add copyright notice, rcsid string and log message. 163 * 164 * Revision 1.2 1997/09/30 16:13:39 gjm11 165 * Add options: -d <chars>, -l <width>, -p, -s, -t <width>, -h . 166 * Parse options with `getopt'. Clean up code generally. 167 * Make comments more accurate. 168 * 169 * Revision 1.1 1997/09/30 11:29:57 gjm11 170 * Initial revision 171 */ 172 173 #include <err.h> 174 #include <limits.h> 175 #include <locale.h> 176 #include <stdio.h> 177 #include <stdlib.h> 178 #include <string.h> 179 #include <sysexits.h> 180 #include <unistd.h> 181 #include <wchar.h> 182 #include <wctype.h> 183 184 /* Something that, we hope, will never be a genuine line length, 185 * indentation etc. 186 */ 187 #define SILLY ((size_t)-1) 188 189 /* I used to use |strtoul| for this, but (1) not all systems have it 190 * and (2) it's probably better to use |strtol| to detect negative 191 * numbers better. 192 * If |fussyp==0| then we don't complain about non-numbers 193 * (returning 0 instead), but we do complain about bad numbers. 194 */ 195 static size_t 196 get_positive(const char *s, const char *err_mess, int fussyP) { 197 char *t; 198 long result = strtol(s,&t,0); 199 if (*t) { if (fussyP) goto Lose; else return 0; } 200 if (result<=0) { Lose: errx(EX_USAGE, "%s", err_mess); } 201 return (size_t) result; 202 } 203 204 static size_t 205 get_nonnegative(const char *s, const char *err_mess, int fussyP) { 206 char *t; 207 long result = strtol(s,&t,0); 208 if (*t) { if (fussyP) goto Lose; else return 0; } 209 if (result<0) { Lose: errx(EX_USAGE, "%s", err_mess); } 210 return (size_t) result; 211 } 212 213 /* Global variables */ 214 215 static int centerP=0; /* Try to center lines? */ 216 static size_t goal_length=0; /* Target length for output lines */ 217 static size_t max_length=0; /* Maximum length for output lines */ 218 static int coalesce_spaces_P=0; /* Coalesce multiple whitespace -> ' ' ? */ 219 static int allow_indented_paragraphs=0; /* Can first line have diff. ind.? */ 220 static int tab_width=8; /* Number of spaces per tab stop */ 221 static size_t output_tab_width=8; /* Ditto, when squashing leading spaces */ 222 static const wchar_t *sentence_enders=L".?!"; /* Double-space after these */ 223 static int grok_mail_headers=0; /* treat embedded mail headers magically? */ 224 static int format_troff=0; /* Format troff? */ 225 226 static int n_errors=0; /* Number of failed files. Return on exit. */ 227 static wchar_t *output_buffer=0; /* Output line will be built here */ 228 static size_t x; /* Horizontal position in output line */ 229 static size_t x0; /* Ditto, ignoring leading whitespace */ 230 static size_t output_buffer_length = 0; 231 static size_t pending_spaces; /* Spaces to add before next word */ 232 static int output_in_paragraph=0; /* Any of current para written out yet? */ 233 234 /* Prototypes */ 235 236 static void process_named_file (const char *); 237 static void process_stream (FILE *, const char *); 238 static size_t indent_length (const wchar_t *, size_t); 239 static int might_be_header (const wchar_t *); 240 static void new_paragraph (size_t, size_t); 241 static void output_word (size_t, size_t, const wchar_t *, size_t, 242 size_t); 243 static void output_indent (size_t); 244 static void center_stream (FILE *, const char *); 245 static wchar_t * get_line (FILE *, size_t *); 246 static void * xrealloc (void *, size_t); 247 248 #define XMALLOC(x) xrealloc(0,x) 249 250 /* Here is perhaps the right place to mention that this code is 251 * all in top-down order. Hence, |main| comes first. 252 */ 253 int 254 main(int argc, char *argv[]) { 255 int ch; /* used for |getopt| processing */ 256 wchar_t *tmp; 257 size_t len; 258 const char *src; 259 260 (void) setlocale(LC_CTYPE, ""); 261 262 /* 1. Grok parameters. */ 263 264 while ((ch = getopt(argc, argv, "0123456789cd:hl:mnpst:w:")) != -1) 265 switch(ch) { 266 case 'c': 267 centerP = 1; 268 format_troff = 1; 269 continue; 270 case 'd': 271 src = optarg; 272 len = mbsrtowcs(NULL, &src, 0, NULL); 273 if (len == (size_t)-1) 274 err(EX_USAGE, "bad sentence-ending character set"); 275 tmp = XMALLOC((len + 1) * sizeof(wchar_t)); 276 mbsrtowcs(tmp, &src, len + 1, NULL); 277 sentence_enders = tmp; 278 continue; 279 case 'l': 280 output_tab_width 281 = get_nonnegative(optarg, "output tab width must be non-negative", 1); 282 continue; 283 case 'm': 284 grok_mail_headers = 1; 285 continue; 286 case 'n': 287 format_troff = 1; 288 continue; 289 case 'p': 290 allow_indented_paragraphs = 1; 291 continue; 292 case 's': 293 coalesce_spaces_P = 1; 294 continue; 295 case 't': 296 tab_width = get_positive(optarg, "tab width must be positive", 1); 297 continue; 298 case 'w': 299 goal_length = get_positive(optarg, "width must be positive", 1); 300 max_length = goal_length; 301 continue; 302 case '0': case '1': case '2': case '3': case '4': case '5': 303 case '6': case '7': case '8': case '9': 304 /* XXX this is not a stylistically approved use of getopt() */ 305 if (goal_length==0) { 306 char *p; 307 p = argv[optind - 1]; 308 if (p[0] == '-' && p[1] == ch && !p[2]) 309 goal_length = get_positive(++p, "width must be nonzero", 1); 310 else 311 goal_length = get_positive(argv[optind]+1, 312 "width must be nonzero", 1); 313 max_length = goal_length; 314 } 315 continue; 316 case 'h': default: 317 fprintf(stderr, 318 "usage: fmt [-cmps] [-d chars] [-l num] [-t num]\n" 319 " [-w width | -width | goal [maximum]] [file ...]\n" 320 "Options: -c center each line instead of formatting\n" 321 " -d <chars> double-space after <chars> at line end\n" 322 " -l <n> turn each <n> spaces at start of line into a tab\n" 323 " -m try to make sure mail header lines stay separate\n" 324 " -n format lines beginning with a dot\n" 325 " -p allow indented paragraphs\n" 326 " -s coalesce whitespace inside lines\n" 327 " -t <n> have tabs every <n> columns\n" 328 " -w <n> set maximum width to <n>\n" 329 " goal set target width to goal\n"); 330 exit(ch=='h' ? 0 : EX_USAGE); 331 } 332 argc -= optind; argv += optind; 333 334 /* [ goal [ maximum ] ] */ 335 336 if (argc>0 && goal_length==0 337 && (goal_length=get_positive(*argv,"goal length must be positive", 0)) 338 != 0) { 339 --argc; ++argv; 340 if (argc>0 341 && (max_length=get_positive(*argv,"max length must be positive", 0)) 342 != 0) { 343 --argc; ++argv; 344 if (max_length<goal_length) 345 errx(EX_USAGE, "max length must be >= goal length"); 346 } 347 } 348 if (goal_length==0) goal_length = 65; 349 if (max_length==0) max_length = goal_length+10; 350 if (max_length >= SIZE_T_MAX / sizeof (wchar_t)) errx(EX_USAGE, "max length too large"); 351 /* really needn't be longer */ 352 output_buffer = XMALLOC((max_length+1) * sizeof(wchar_t)); 353 354 /* 2. Process files. */ 355 356 if (argc>0) { 357 while (argc-->0) process_named_file(*argv++); 358 } 359 else { 360 process_stream(stdin, "standard input"); 361 } 362 363 /* We're done. */ 364 365 return n_errors ? EX_NOINPUT : 0; 366 367 } 368 369 /* Process a single file, given its name. 370 */ 371 static void 372 process_named_file(const char *name) { 373 FILE *f=fopen(name, "r"); 374 if (!f) { warn("%s", name); ++n_errors; } 375 else { 376 process_stream(f, name); 377 if (ferror(f)) { warn("%s", name); ++n_errors; } 378 fclose(f); 379 } 380 } 381 382 /* Types of mail header continuation lines: 383 */ 384 typedef enum { 385 hdr_ParagraphStart = -1, 386 hdr_NonHeader = 0, 387 hdr_Header = 1, 388 hdr_Continuation = 2 389 } HdrType; 390 391 /* Process a stream. This is where the real work happens, 392 * except that centering is handled separately. 393 */ 394 static void 395 process_stream(FILE *stream, const char *name) { 396 size_t last_indent=SILLY; /* how many spaces in last indent? */ 397 size_t para_line_number=0; /* how many lines already read in this para? */ 398 size_t first_indent=SILLY; /* indentation of line 0 of paragraph */ 399 HdrType prev_header_type=hdr_ParagraphStart; 400 /* ^-- header_type of previous line; -1 at para start */ 401 wchar_t *line; 402 size_t length; 403 404 if (centerP) { center_stream(stream, name); return; } 405 while ((line=get_line(stream,&length)) != NULL) { 406 size_t np=indent_length(line, length); 407 { HdrType header_type=hdr_NonHeader; 408 if (grok_mail_headers && prev_header_type!=hdr_NonHeader) { 409 if (np==0 && might_be_header(line)) 410 header_type = hdr_Header; 411 else if (np>0 && prev_header_type>hdr_NonHeader) 412 header_type = hdr_Continuation; 413 } 414 /* We need a new paragraph if and only if: 415 * this line is blank, 416 * OR it's a troff request (and we don't format troff), 417 * OR it's a mail header, 418 * OR it's not a mail header AND the last line was one, 419 * OR the indentation has changed 420 * AND the line isn't a mail header continuation line 421 * AND this isn't the second line of an indented paragraph. 422 */ 423 if ( length==0 424 || (line[0]=='.' && !format_troff) 425 || header_type==hdr_Header 426 || (header_type==hdr_NonHeader && prev_header_type>hdr_NonHeader) 427 || (np!=last_indent 428 && header_type != hdr_Continuation 429 && (!allow_indented_paragraphs || para_line_number != 1)) ) { 430 new_paragraph(output_in_paragraph ? last_indent : first_indent, np); 431 para_line_number = 0; 432 first_indent = np; 433 last_indent = np; 434 if (header_type==hdr_Header) last_indent=2; /* for cont. lines */ 435 if (length==0 || (line[0]=='.' && !format_troff)) { 436 if (length==0) 437 putwchar('\n'); 438 else 439 wprintf(L"%.*ls\n", (int)length, line); 440 prev_header_type=hdr_ParagraphStart; 441 continue; 442 } 443 } 444 else { 445 /* If this is an indented paragraph other than a mail header 446 * continuation, set |last_indent|. 447 */ 448 if (np != last_indent && header_type != hdr_Continuation) 449 last_indent=np; 450 } 451 prev_header_type = header_type; 452 } 453 454 { size_t n=np; 455 while (n<length) { 456 /* Find word end and count spaces after it */ 457 size_t word_length=0, space_length=0; 458 while (n+word_length < length && line[n+word_length] != ' ') 459 ++word_length; 460 space_length = word_length; 461 while (n+space_length < length && line[n+space_length] == ' ') 462 ++space_length; 463 /* Send the word to the output machinery. */ 464 output_word(first_indent, last_indent, 465 line+n, word_length, space_length-word_length); 466 n += space_length; 467 } 468 } 469 ++para_line_number; 470 } 471 new_paragraph(output_in_paragraph ? last_indent : first_indent, 0); 472 if (ferror(stream)) { warn("%s", name); ++n_errors; } 473 } 474 475 /* How long is the indent on this line? 476 */ 477 static size_t 478 indent_length(const wchar_t *line, size_t length) { 479 size_t n=0; 480 while (n<length && *line++ == ' ') ++n; 481 return n; 482 } 483 484 /* Might this line be a mail header? 485 * We deem a line to be a possible header if it matches the 486 * Perl regexp /^[A-Z][-A-Za-z0-9]*:\s/. This is *not* the same 487 * as in RFC whatever-number-it-is; we want to be gratuitously 488 * conservative to avoid mangling ordinary civilised text. 489 */ 490 static int 491 might_be_header(const wchar_t *line) { 492 if (!iswupper(*line++)) return 0; 493 while (*line && (iswalnum(*line) || *line=='-')) ++line; 494 return (*line==':' && iswspace(line[1])); 495 } 496 497 /* Begin a new paragraph with an indent of |indent| spaces. 498 */ 499 static void 500 new_paragraph(size_t old_indent, size_t indent) { 501 if (output_buffer_length) { 502 if (old_indent>0) output_indent(old_indent); 503 wprintf(L"%.*ls\n", (int)output_buffer_length, output_buffer); 504 } 505 x=indent; x0=0; output_buffer_length=0; pending_spaces=0; 506 output_in_paragraph = 0; 507 } 508 509 /* Output spaces or tabs for leading indentation. 510 */ 511 static void 512 output_indent(size_t n_spaces) { 513 if (output_tab_width) { 514 while (n_spaces >= output_tab_width) { 515 putwchar('\t'); 516 n_spaces -= output_tab_width; 517 } 518 } 519 while (n_spaces-- > 0) putwchar(' '); 520 } 521 522 /* Output a single word, or add it to the buffer. 523 * indent0 and indent1 are the indents to use on the first and subsequent 524 * lines of a paragraph. They'll often be the same, of course. 525 */ 526 static void 527 output_word(size_t indent0, size_t indent1, const wchar_t *word, size_t length, size_t spaces) { 528 size_t new_x; 529 size_t indent = output_in_paragraph ? indent1 : indent0; 530 size_t width; 531 const wchar_t *p; 532 int cwidth; 533 534 for (p = word, width = 0; p < &word[length]; p++) 535 width += (cwidth = wcwidth(*p)) > 0 ? cwidth : 1; 536 537 new_x = x + pending_spaces + width; 538 539 /* If either |spaces==0| (at end of line) or |coalesce_spaces_P| 540 * (squashing internal whitespace), then add just one space; 541 * except that if the last character was a sentence-ender we 542 * actually add two spaces. 543 */ 544 if (coalesce_spaces_P || spaces==0) 545 spaces = wcschr(sentence_enders, word[length-1]) ? 2 : 1; 546 547 if (new_x<=goal_length) { 548 /* After adding the word we still aren't at the goal length, 549 * so clearly we add it to the buffer rather than outputing it. 550 */ 551 wmemset(output_buffer+output_buffer_length, L' ', pending_spaces); 552 x0 += pending_spaces; x += pending_spaces; 553 output_buffer_length += pending_spaces; 554 wmemcpy(output_buffer+output_buffer_length, word, length); 555 x0 += width; x += width; output_buffer_length += length; 556 pending_spaces = spaces; 557 } 558 else { 559 /* Adding the word takes us past the goal. Print the line-so-far, 560 * and the word too iff either (1) the lsf is empty or (2) that 561 * makes us nearer the goal but doesn't take us over the limit, 562 * or (3) the word on its own takes us over the limit. 563 * In case (3) we put a newline in between. 564 */ 565 if (indent>0) output_indent(indent); 566 wprintf(L"%.*ls", (int)output_buffer_length, output_buffer); 567 if (x0==0 || (new_x <= max_length && new_x-goal_length <= goal_length-x)) { 568 wprintf(L"%*ls", (int)pending_spaces, L""); 569 goto write_out_word; 570 } 571 else { 572 /* If the word takes us over the limit on its own, just 573 * spit it out and don't bother buffering it. 574 */ 575 if (indent+width > max_length) { 576 putwchar('\n'); 577 if (indent>0) output_indent(indent); 578 write_out_word: 579 wprintf(L"%.*ls", (int)length, word); 580 x0 = 0; x = indent1; pending_spaces = 0; 581 output_buffer_length = 0; 582 } 583 else { 584 wmemcpy(output_buffer, word, length); 585 x0 = width; x = width+indent1; pending_spaces = spaces; 586 output_buffer_length = length; 587 } 588 } 589 putwchar('\n'); 590 output_in_paragraph = 1; 591 } 592 } 593 594 /* Process a stream, but just center its lines rather than trying to 595 * format them neatly. 596 */ 597 static void 598 center_stream(FILE *stream, const char *name) { 599 wchar_t *line, *p; 600 size_t length; 601 size_t width; 602 int cwidth; 603 while ((line=get_line(stream, &length)) != NULL) { 604 size_t l=length; 605 while (l>0 && iswspace(*line)) { ++line; --l; } 606 length=l; 607 for (p = line, width = 0; p < &line[length]; p++) 608 width += (cwidth = wcwidth(*p)) > 0 ? cwidth : 1; 609 l = width; 610 while (l<goal_length) { putwchar(' '); l+=2; } 611 wprintf(L"%.*ls\n", (int)length, line); 612 } 613 if (ferror(stream)) { warn("%s", name); ++n_errors; } 614 } 615 616 /* Get a single line from a stream. Expand tabs, strip control 617 * characters and trailing whitespace, and handle backspaces. 618 * Return the address of the buffer containing the line, and 619 * put the length of the line in |lengthp|. 620 * This can cope with arbitrarily long lines, and with lines 621 * without terminating \n. 622 * If there are no characters left or an error happens, we 623 * return 0. 624 * Don't confuse |spaces_pending| here with the global 625 * |pending_spaces|. 626 */ 627 static wchar_t * 628 get_line(FILE *stream, size_t *lengthp) { 629 static wchar_t *buf=NULL; 630 static size_t length=0; 631 size_t len=0; 632 wint_t ch; 633 size_t spaces_pending=0; 634 int troff=0; 635 size_t col=0; 636 int cwidth; 637 638 if (buf==NULL) { length=100; buf=XMALLOC(length * sizeof(wchar_t)); } 639 while ((ch=getwc(stream)) != '\n' && ch != WEOF) { 640 if (len+spaces_pending==0 && ch=='.' && !format_troff) troff=1; 641 if (ch==' ') ++spaces_pending; 642 else if (troff || iswprint(ch)) { 643 while (len+spaces_pending >= length) { 644 length*=2; buf=xrealloc(buf, length * sizeof(wchar_t)); 645 } 646 while (spaces_pending > 0) { --spaces_pending; buf[len++]=' '; col++; } 647 buf[len++] = ch; 648 col += (cwidth = wcwidth(ch)) > 0 ? cwidth : 1; 649 } 650 else if (ch=='\t') 651 spaces_pending += tab_width - (col+spaces_pending)%tab_width; 652 else if (ch=='\b') { if (len) --len; if (col) --col; } 653 } 654 *lengthp=len; 655 return (len>0 || ch!=WEOF) ? buf : 0; 656 } 657 658 /* (Re)allocate some memory, exiting with an error if we can't. 659 */ 660 static void * 661 xrealloc(void *ptr, size_t nbytes) { 662 void *p = realloc(ptr, nbytes); 663 if (p == NULL) errx(EX_OSERR, "out of memory"); 664 return p; 665 } 666