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: src/usr.bin/fmt/fmt.c,v 1.12.2.2 2002/01/14 09:48:26 ru Exp $ 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 <ctype.h> 174 #include <err.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> 181 182 /* Something that, we hope, will never be a genuine line length, 183 * indentation etc. 184 */ 185 #define SILLY ((size_t)-1) 186 187 /* I used to use |strtoul| for this, but (1) not all systems have it 188 * and (2) it's probably better to use |strtol| to detect negative 189 * numbers better. 190 * If |fussyp==0| then we don't complain about non-numbers 191 * (returning 0 instead), but we do complain about bad numbers. 192 */ 193 static size_t 194 get_positive(const char *s, const char *err_mess, int fussyP) { 195 char *t; 196 long result = strtol(s,&t,0); 197 if (*t) { if (fussyP) goto Lose; else return 0; } 198 if (result<=0) { Lose: errx(EX_USAGE, "%s", err_mess); } 199 return (size_t) result; 200 } 201 202 static size_t 203 get_nonnegative(const char *s, const char *err_mess, int fussyP) { 204 char *t; 205 long result = strtol(s,&t,0); 206 if (*t) { if (fussyP) goto Lose; else return 0; } 207 if (result<0) { Lose: errx(EX_USAGE, "%s", err_mess); } 208 return (size_t) result; 209 } 210 211 /* Global variables */ 212 213 static int centerP=0; /* Try to center lines? */ 214 static size_t goal_length=0; /* Target length for output lines */ 215 static size_t max_length=0; /* Maximum length for output lines */ 216 static int coalesce_spaces_P=0; /* Coalesce multiple whitespace -> ' ' ? */ 217 static int allow_indented_paragraphs=0; /* Can first line have diff. ind.? */ 218 static int tab_width=8; /* Number of spaces per tab stop */ 219 static size_t output_tab_width=8; /* Ditto, when squashing leading spaces */ 220 static const char *sentence_enders=".?!"; /* Double-space after these */ 221 static int grok_mail_headers=0; /* treat embedded mail headers magically? */ 222 static int format_troff=0; /* Format troff? */ 223 224 static int n_errors=0; /* Number of failed files. Return on exit. */ 225 static char *output_buffer=NULL; /* Output line will be built here */ 226 static size_t x; /* Horizontal position in output line */ 227 static size_t x0; /* Ditto, ignoring leading whitespace */ 228 static size_t pending_spaces; /* Spaces to add before next word */ 229 static int output_in_paragraph=0; /* Any of current para written out yet? */ 230 231 /* Prototypes */ 232 233 static void process_named_file (const char *); 234 static void process_stream (FILE *, const char *); 235 static size_t indent_length (const char *, size_t); 236 static int might_be_header (const unsigned char *); 237 static void new_paragraph (size_t, size_t); 238 static void output_word (size_t, size_t, const char *, size_t, size_t); 239 static void output_indent (size_t); 240 static void center_stream (FILE *, const char *); 241 static char * get_line (FILE *, size_t *); 242 static void * xrealloc (void *, size_t); 243 244 #define XMALLOC(x) xrealloc(0,x) 245 246 /* Here is perhaps the right place to mention that this code is 247 * all in top-down order. Hence, |main| comes first. 248 */ 249 int 250 main(int argc, char *argv[]) { 251 int ch; /* used for |getopt| processing */ 252 253 254 (void) setlocale(LC_CTYPE, ""); 255 256 /* 1. Grok parameters. */ 257 258 while ((ch = getopt(argc, argv, "0123456789cd:hl:mnpst:w:")) != -1) 259 switch(ch) { 260 case 'c': 261 centerP = 1; 262 format_troff = 1; 263 continue; 264 case 'd': 265 sentence_enders = optarg; 266 continue; 267 case 'l': 268 output_tab_width 269 = get_nonnegative(optarg, "output tab width must be non-negative", 1); 270 continue; 271 case 'm': 272 grok_mail_headers = 1; 273 continue; 274 case 'n': 275 format_troff = 1; 276 continue; 277 case 'p': 278 allow_indented_paragraphs = 1; 279 continue; 280 case 's': 281 coalesce_spaces_P = 1; 282 continue; 283 case 't': 284 tab_width = get_positive(optarg, "tab width must be positive", 1); 285 continue; 286 case 'w': 287 goal_length = get_positive(optarg, "width must be positive", 1); 288 max_length = goal_length; 289 continue; 290 case '0': case '1': case '2': case '3': case '4': case '5': 291 case '6': case '7': case '8': case '9': 292 /* XXX this is not a stylistically approved use of getopt() */ 293 if (goal_length==0) { 294 char *p; 295 p = argv[optind - 1]; 296 if (p[0] == '-' && p[1] == ch && !p[2]) 297 goal_length = get_positive(++p, "width must be nonzero", 1); 298 else 299 goal_length = get_positive(argv[optind]+1, 300 "width must be nonzero", 1); 301 max_length = goal_length; 302 } 303 continue; 304 case 'h': default: 305 fprintf(stderr, 306 "Usage: fmt [-cmps] [-d chars] [-l num] [-t num]\n" 307 " [-w width | -width | goal [maximum]] [file ...]\n" 308 "Options: -c center each line instead of formatting\n" 309 " -d <chars> double-space after <chars> at line end\n" 310 " -l <n> turn each <n> spaces at start of line into a tab\n" 311 " -m try to make sure mail header lines stay separate\n" 312 " -n format lines beginning with a dot\n" 313 " -p allow indented paragraphs\n" 314 " -s coalesce whitespace inside lines\n" 315 " -t <n> have tabs every <n> columns\n" 316 " -w <n> set maximum width to <n>\n" 317 " goal set target width to goal\n"); 318 exit(ch=='h' ? 0 : EX_USAGE); 319 } 320 argc -= optind; argv += optind; 321 322 /* [ goal [ maximum ] ] */ 323 324 if (argc>0 && goal_length==0 325 && (goal_length=get_positive(*argv,"goal length must be positive", 0)) 326 != 0) { 327 --argc; ++argv; 328 if (argc>0 329 && (max_length=get_positive(*argv,"max length must be positive", 0)) 330 != 0) { 331 --argc; ++argv; 332 if (max_length<goal_length) 333 errx(EX_USAGE, "max length must be >= goal length"); 334 } 335 } 336 if (goal_length==0) goal_length = 65; 337 if (max_length==0) max_length = goal_length+10; 338 output_buffer = XMALLOC(max_length+1); /* really needn't be longer */ 339 340 /* 2. Process files. */ 341 342 if (argc>0) { 343 while (argc-->0) process_named_file(*argv++); 344 } 345 else { 346 process_stream(stdin, "standard input"); 347 } 348 349 /* We're done. */ 350 351 return n_errors ? EX_NOINPUT : 0; 352 353 } 354 355 /* Process a single file, given its name. 356 */ 357 static void 358 process_named_file(const char *name) { 359 FILE *f=fopen(name, "r"); 360 if (!f) { perror(name); ++n_errors; } 361 else { 362 process_stream(f, name); 363 fclose(f); 364 } 365 } 366 367 /* Types of mail header continuation lines: 368 */ 369 typedef enum { 370 hdr_ParagraphStart = -1, 371 hdr_NonHeader = 0, 372 hdr_Header = 1, 373 hdr_Continuation = 2 374 } HdrType; 375 376 /* Process a stream. This is where the real work happens, 377 * except that centering is handled separately. 378 */ 379 static void 380 process_stream(FILE *stream, const char *name) { 381 size_t last_indent=SILLY; /* how many spaces in last indent? */ 382 size_t para_line_number=0; /* how many lines already read in this para? */ 383 size_t first_indent=SILLY; /* indentation of line 0 of paragraph */ 384 HdrType prev_header_type=hdr_ParagraphStart; 385 /* ^-- header_type of previous line; -1 at para start */ 386 char *line; 387 size_t length; 388 389 if (centerP) { center_stream(stream, name); return; } 390 while ((line=get_line(stream,&length)) != NULL) { 391 size_t np=indent_length(line, length); 392 { HdrType header_type=hdr_NonHeader; 393 if (grok_mail_headers && prev_header_type!=hdr_NonHeader) { 394 if (np==0 && might_be_header(line)) 395 header_type = hdr_Header; 396 else if (np>0 && prev_header_type>hdr_NonHeader) 397 header_type = hdr_Continuation; 398 } 399 /* We need a new paragraph if and only if: 400 * this line is blank, 401 * OR it's a troff request (and we don't format troff), 402 * OR it's a mail header, 403 * OR it's not a mail header AND the last line was one, 404 * OR the indentation has changed 405 * AND the line isn't a mail header continuation line 406 * AND this isn't the second line of an indented paragraph. 407 */ 408 if ( length==0 409 || (line[0]=='.' && !format_troff) 410 || header_type==hdr_Header 411 || (header_type==hdr_NonHeader && prev_header_type>hdr_NonHeader) 412 || (np!=last_indent 413 && header_type != hdr_Continuation 414 && (!allow_indented_paragraphs || para_line_number != 1)) ) { 415 new_paragraph(output_in_paragraph ? last_indent : first_indent, np); 416 para_line_number = 0; 417 first_indent = np; 418 last_indent = np; 419 if (header_type==hdr_Header) last_indent=2; /* for cont. lines */ 420 if (length==0 || (line[0]=='.' && !format_troff)) { 421 if (length==0) 422 putchar('\n'); 423 else 424 printf("%.*s\n", (int)length, line); 425 prev_header_type=hdr_ParagraphStart; 426 continue; 427 } 428 } 429 else { 430 /* If this is an indented paragraph other than a mail header 431 * continuation, set |last_indent|. 432 */ 433 if (np != last_indent && header_type != hdr_Continuation) 434 last_indent=np; 435 } 436 prev_header_type = header_type; 437 } 438 439 { size_t n=np; 440 while (n<length) { 441 /* Find word end and count spaces after it */ 442 size_t word_length=0, space_length=0; 443 while (n+word_length < length && line[n+word_length] != ' ') 444 ++word_length; 445 space_length = word_length; 446 while (n+space_length < length && line[n+space_length] == ' ') 447 ++space_length; 448 /* Send the word to the output machinery. */ 449 output_word(first_indent, last_indent, 450 line+n, word_length, space_length-word_length); 451 n += space_length; 452 } 453 } 454 ++para_line_number; 455 } 456 new_paragraph(output_in_paragraph ? last_indent : first_indent, 0); 457 if (ferror(stream)) { perror(name); ++n_errors; } 458 } 459 460 /* How long is the indent on this line? 461 */ 462 static size_t 463 indent_length(const char *line, size_t length) { 464 size_t n=0; 465 while (n<length && *line++ == ' ') ++n; 466 return n; 467 } 468 469 /* Might this line be a mail header? 470 * We deem a line to be a possible header if it matches the 471 * Perl regexp /^[A-Z][-A-Za-z0-9]*:\s/. This is *not* the same 472 * as in RFC whatever-number-it-is; we want to be gratuitously 473 * conservative to avoid mangling ordinary civilised text. 474 */ 475 static int 476 might_be_header(const unsigned char *line) { 477 if (!isupper(*line++)) return 0; 478 while (*line && (isalnum(*line) || *line=='-')) ++line; 479 return (*line==':' && isspace(line[1])); 480 } 481 482 /* Begin a new paragraph with an indent of |indent| spaces. 483 */ 484 static void 485 new_paragraph(size_t old_indent, size_t indent) { 486 if (x0) { 487 if (old_indent>0) output_indent(old_indent); 488 fwrite(output_buffer, 1, x0, stdout); 489 putchar('\n'); 490 } 491 x=indent; x0=0; pending_spaces=0; 492 output_in_paragraph = 0; 493 } 494 495 /* Output spaces or tabs for leading indentation. 496 */ 497 static void 498 output_indent(size_t n_spaces) { 499 if (output_tab_width) { 500 while (n_spaces >= output_tab_width) { 501 putchar('\t'); 502 n_spaces -= output_tab_width; 503 } 504 } 505 while (n_spaces-- > 0) putchar(' '); 506 } 507 508 /* Output a single word, or add it to the buffer. 509 * indent0 and indent1 are the indents to use on the first and subsequent 510 * lines of a paragraph. They'll often be the same, of course. 511 */ 512 static void 513 output_word(size_t indent0, size_t indent1, const char *word, size_t length, size_t spaces) { 514 size_t new_x = x+pending_spaces+length; 515 size_t indent = output_in_paragraph ? indent1 : indent0; 516 517 /* If either |spaces==0| (at end of line) or |coalesce_spaces_P| 518 * (squashing internal whitespace), then add just one space; 519 * except that if the last character was a sentence-ender we 520 * actually add two spaces. 521 */ 522 if (coalesce_spaces_P || spaces==0) 523 spaces = strchr(sentence_enders, word[length-1]) ? 2 : 1; 524 525 if (new_x<=goal_length) { 526 /* After adding the word we still aren't at the goal length, 527 * so clearly we add it to the buffer rather than outputing it. 528 */ 529 memset(output_buffer+x0, ' ', pending_spaces); 530 x0 += pending_spaces; x += pending_spaces; 531 memcpy(output_buffer+x0, word, length); 532 x0 += length; x += length; 533 pending_spaces = spaces; 534 } 535 else { 536 /* Adding the word takes us past the goal. Print the line-so-far, 537 * and the word too iff either (1) the lsf is empty or (2) that 538 * makes us nearer the goal but doesn't take us over the limit, 539 * or (3) the word on its own takes us over the limit. 540 * In case (3) we put a newline in between. 541 */ 542 if (indent>0) output_indent(indent); 543 fwrite(output_buffer, 1, x0, stdout); 544 if (x0==0 || (new_x <= max_length && new_x-goal_length <= goal_length-x)) { 545 printf("%*s", (int)pending_spaces, ""); 546 goto write_out_word; 547 } 548 else { 549 /* If the word takes us over the limit on its own, just 550 * spit it out and don't bother buffering it. 551 */ 552 if (indent+length > max_length) { 553 putchar('\n'); 554 if (indent>0) output_indent(indent); 555 write_out_word: 556 fwrite(word, 1, length, stdout); 557 x0 = 0; x = indent1; pending_spaces = 0; 558 } 559 else { 560 memcpy(output_buffer, word, length); 561 x0 = length; x = length+indent1; pending_spaces = spaces; 562 } 563 } 564 putchar('\n'); 565 output_in_paragraph = 1; 566 } 567 } 568 569 /* Process a stream, but just center its lines rather than trying to 570 * format them neatly. 571 */ 572 static void 573 center_stream(FILE *stream, const char *name) { 574 char *line; 575 size_t length; 576 while ((line=get_line(stream, &length)) != NULL) { 577 size_t l=length; 578 while (l>0 && isspace(*line)) { ++line; --l; } 579 length=l; 580 while (l<goal_length) { putchar(' '); l+=2; } 581 fwrite(line, 1, length, stdout); 582 putchar('\n'); 583 } 584 if (ferror(stream)) { perror(name); ++n_errors; } 585 } 586 587 /* Get a single line from a stream. Expand tabs, strip control 588 * characters and trailing whitespace, and handle backspaces. 589 * Return the address of the buffer containing the line, and 590 * put the length of the line in |lengthp|. 591 * This can cope with arbitrarily long lines, and with lines 592 * without terminating \n. 593 * If there are no characters left or an error happens, we 594 * return 0. 595 * Don't confuse |spaces_pending| here with the global 596 * |pending_spaces|. 597 */ 598 static char * 599 get_line(FILE *stream, size_t *lengthp) { 600 static char *buf=NULL; 601 static size_t length=0; 602 size_t len=0; 603 int ch; 604 size_t spaces_pending=0; 605 int troff=0; 606 607 if (buf==NULL) { length=100; buf=XMALLOC(length); } 608 while ((ch=getc(stream)) != '\n' && ch != EOF) { 609 if (len+spaces_pending==0 && ch=='.' && !format_troff) troff=1; 610 if (ch==' ') ++spaces_pending; 611 else if (troff || isprint(ch)) { 612 while (len+spaces_pending >= length) { 613 length*=2; buf=xrealloc(buf, length); 614 } 615 while (spaces_pending > 0) { --spaces_pending; buf[len++]=' '; } 616 buf[len++] = ch; 617 } 618 else if (ch=='\t') 619 spaces_pending += tab_width - (len+spaces_pending)%tab_width; 620 else if (ch=='\b') { if (len) --len; } 621 } 622 *lengthp=len; 623 return (len>0 || ch!=EOF) ? buf : 0; 624 } 625 626 /* (Re)allocate some memory, exiting with an error if we can't. 627 */ 628 static void * 629 xrealloc(void *ptr, size_t nbytes) { 630 void *p = realloc(ptr, nbytes); 631 if (p == NULL) errx(EX_OSERR, "out of memory"); 632 return p; 633 } 634