Annotation of src/usr.bin/fmt/fmt.c, Revision 1.10
1.10 ! millert 1: /* $OpenBSD$ */
1.1 deraadt 2:
1.10 ! millert 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: * 3. The "everything else" is split into words; a word
! 34: * includes its trailing whitespace, and a word at the
! 35: * end of a line is deemed to be followed by a single
! 36: * space, or two spaces if it ends with a sentence-end
! 37: * character. (See the `-d' option for how to change that.)
! 38: * If the `-s' option has been given, then a word's trailing
! 39: * whitespace is replaced by what it would have had if it
! 40: * had occurred at end of line.
! 41: * 4. Each paragraph is sent to standard output as follows.
! 42: * We output the leading whitespace, and then enough words
! 43: * to make the line length as near as possible to the goal
! 44: * without exceeding the maximum. (If a single word would
! 45: * exceed the maximum, we output that anyway.) Of course
! 46: * the trailing whitespace of the last word is ignored.
! 47: * We then emit a newline and start again if there are any
! 48: * words left.
! 49: * Note that for a blank line this translates as "We emit
! 50: * a newline".
! 51: * If the `-l <n>' option is given, then leading whitespace
! 52: * is modified slightly: <n> spaces are replaced by a tab.
! 53: * Indented paragraphs (see above under `-p') make matters
! 54: * more complicated than this suggests. Actually every paragraph
! 55: * has two `leading whitespace' values; the value for the first
! 56: * line, and the value for the most recent line. (While processing
! 57: * the first line, the two are equal. When `-p' has not been
! 58: * given, they are always equal.) The leading whitespace
! 59: * actually output is that of the first line (for the first
! 60: * line of *output*) or that of the most recent line (for
! 61: * all other lines of output).
! 62: * When `-m' has been given, message header paragraphs are
! 63: * taken as having first-leading-whitespace empty and
! 64: * subsequent-leading-whitespace two spaces.
! 65: *
! 66: * Multiple input files are formatted one at a time, so that a file
! 67: * never ends in the middle of a line.
! 68: *
! 69: * There's an alternative mode of operation, invoked by giving
! 70: * the `-c' option. In that case we just center every line,
! 71: * and most of the other options are ignored. This should
! 72: * really be in a separate program, but we must stay compatible
! 73: * with old `fmt'.
! 74: *
! 75: * QUERY: Should `-m' also try to do the right thing with quoted text?
! 76: * QUERY: `-b' to treat backslashed whitespace as old `fmt' does?
! 77: * QUERY: Option meaning `never join lines'?
! 78: * QUERY: Option meaning `split in mid-word to avoid overlong lines'?
! 79: * (Those last two might not be useful, since we have `fold'.)
! 80: *
! 81: * Differences from old `fmt':
! 82: *
! 83: * - We have many more options. Options that aren't understood
! 84: * generate a lengthy usage message, rather than being
! 85: * treated as filenames.
! 86: * - Even with `-m', our handling of message headers is
! 87: * significantly different. (And much better.)
! 88: * - We don't treat `\ ' as non-word-breaking.
! 89: * - Downward changes of indentation start new paragraphs
! 90: * for us, as well as upward. (I think old `fmt' behaves
! 91: * in the way it does in order to allow indented paragraphs,
! 92: * but this is a broken way of making indented paragraphs
! 93: * behave right.)
! 94: * - Given the choice of going over or under |goal_length|
! 95: * by the same amount, we go over; old `fmt' goes under.
! 96: * - We treat `?' as ending a sentence, and not `:'. Old `fmt'
! 97: * does the reverse.
! 98: * - We return approved return codes. Old `fmt' returns
! 99: * 1 for some errors, and *the number of unopenable files*
! 100: * when that was all that went wrong.
! 101: * - We have fewer crashes and more helpful error messages.
! 102: * - We don't turn spaces into tabs at starts of lines unless
! 103: * specifically requested.
! 104: * - New `fmt' is somewhat smaller and slightly faster than
! 105: * old `fmt'.
! 106: *
! 107: * Bugs:
! 108: *
! 109: * None known. There probably are some, though.
! 110: *
! 111: * Portability:
! 112: *
! 113: * I believe this code to be pretty portable. It does require
! 114: * that you have `getopt'. If you need to include "getopt.h"
! 115: * for this (e.g., if your system didn't come with `getopt'
! 116: * and you installed it yourself) then you should arrange for
! 117: * NEED_getopt_h to be #defined.
! 118: *
! 119: * Everything here should work OK even on nasty 16-bit
! 120: * machines and nice 64-bit ones. However, it's only really
! 121: * been tested on my FreeBSD machine. Your mileage may vary.
! 122: */
! 123:
! 124: /* Copyright (c) 1997 Gareth McCaughan. All rights reserved.
! 125: *
! 126: * Redistribution and use of this code, in source or binary forms,
! 127: * with or without modification, are permitted subject to the following
! 128: * conditions:
! 129: *
! 130: * - Redistribution of source code must retain the above copyright
1.1 deraadt 131: * notice, this list of conditions and the following disclaimer.
1.10 ! millert 132: *
! 133: * - If you distribute modified source code it must also include
! 134: * a notice saying that it has been modified, and giving a brief
! 135: * description of what changes have been made.
! 136: *
! 137: * Disclaimer: I am not responsible for the results of using this code.
! 138: * If it formats your hard disc, sends obscene messages to
! 139: * your boss and kills your children then that's your problem
! 140: * not mine. I give absolutely no warranty of any sort as to
! 141: * what the program will do, and absolutely refuse to be held
! 142: * liable for any consequences of your using it.
! 143: * Thank you. Have a nice day.
! 144: */
! 145:
! 146: /* RCS change log:
! 147: * Revision 1.5 1998/03/02 18:02:21 gjm11
! 148: * Minor changes for portability.
! 149: *
! 150: * Revision 1.4 1997/10/01 11:51:28 gjm11
! 151: * Repair broken indented-paragraph handling.
! 152: * Add mail message header stuff.
! 153: * Improve comments and layout.
! 154: * Make usable with non-BSD systems.
! 155: * Add revision display to usage message.
! 156: *
! 157: * Revision 1.3 1997/09/30 16:24:47 gjm11
! 158: * Add copyright notice, rcsid string and log message.
! 159: *
! 160: * Revision 1.2 1997/09/30 16:13:39 gjm11
! 161: * Add options: -d <chars>, -l <width>, -p, -s, -t <width>, -h .
! 162: * Parse options with `getopt'. Clean up code generally.
! 163: * Make comments more accurate.
! 164: *
! 165: * Revision 1.1 1997/09/30 11:29:57 gjm11
! 166: * Initial revision
1.1 deraadt 167: */
168:
169: #ifndef lint
1.10 ! millert 170: static const char rcsid[] =
! 171: "$OpenBSD: fmt.c,v 1.5 1998/03/02 18:02:21 gjm11 Exp $";
! 172: static const char copyright[] =
! 173: "Copyright (c) 1997 Gareth McCaughan. All rights reserved.\n";
1.1 deraadt 174: #endif /* not lint */
175:
1.10 ! millert 176: /* Cater for BSD and non-BSD systems.
! 177: * I hate the C preprocessor.
! 178: */
! 179:
! 180: #undef HAVE_errx
! 181: #undef HAVE_sysexits
! 182:
! 183: #ifdef unix
! 184: # include <sys/param.h>
! 185: # ifdef BSD
! 186: # define HAVE_errx
! 187: # if BSD >= 199306
! 188: # define HAVE_sysexits
! 189: # endif
! 190: # endif
! 191: #endif
! 192:
! 193: #ifdef HAVE_errx
! 194: # include <err.h>
! 195: #else
! 196: # define errx(rc,str) { fprintf(stderr,"fmt: %s\n",str); exit(rc); }
! 197: #endif
! 198:
! 199: #ifdef HAVE_sysexits
! 200: # include <sysexits.h>
1.4 millert 201: #else
1.10 ! millert 202: # define EX_USAGE 1
! 203: # define EX_NOINPUT 1
! 204: # define EX_SOFTWARE 1
! 205: # define EX_OSERR 1
1.1 deraadt 206: #endif
207:
1.4 millert 208: #include <ctype.h>
1.1 deraadt 209: #include <stdio.h>
210: #include <stdlib.h>
211: #include <string.h>
212:
1.10 ! millert 213: #ifdef NEED_getopt_h
! 214: # include "getopt.h"
! 215: #endif
! 216:
! 217: /* Something that, we hope, will never be a genuine line length,
! 218: * indentation etc.
1.1 deraadt 219: */
1.10 ! millert 220: #define SILLY ((size_t)-1)
1.1 deraadt 221:
1.10 ! millert 222: /* I used to use |strtoul| for this, but (1) not all systems have it
! 223: * and (2) it's probably better to use |strtol| to detect negative
! 224: * numbers better.
! 225: * If |fussyp==0| then we don't complain about non-numbers
! 226: * (returning 0 instead), but we do complain about bad numbers.
! 227: */
! 228: size_t get_positive(const char *s, const char *err_mess, int fussyP) {
! 229: char *t;
! 230: long result = strtol(s,&t,0);
! 231: if (*t) { if (fussyP) goto Lose; else return 0; }
! 232: if (result<=0) { Lose: errx(EX_USAGE, err_mess); }
! 233: return (size_t) result;
1.1 deraadt 234: }
235:
1.10 ! millert 236: /* Just for the sake of linguistic purity: */
! 237:
! 238: #ifdef BRITISH
! 239: # define CENTER "centre"
! 240: #else
! 241: # define CENTER "center"
! 242: #endif
! 243:
! 244: /* Global variables */
! 245:
! 246: static int centerP=0; /* Try to center lines? */
! 247: static size_t goal_length=0; /* Target length for output lines */
! 248: static size_t max_length=0; /* Maximum length for output lines */
! 249: static int coalesce_spaces_P=0; /* Coalesce multiple whitespace -> ' ' ? */
! 250: static int allow_indented_paragraphs=0; /* Can first line have diff. ind.? */
! 251: static int tab_width=8; /* Number of spaces per tab stop */
! 252: static int output_tab_width=0; /* Ditto, when squashing leading spaces */
! 253: static char *sentence_enders=".?!"; /* Double-space after these */
! 254: static int grok_mail_headers=0; /* treat embedded mail headers magically? */
! 255:
! 256: static int n_errors=0; /* Number of failed files. Return on exit. */
! 257: static char *output_buffer=0; /* Output line will be built here */
! 258: static size_t x; /* Horizontal position in output line */
! 259: static size_t x0; /* Ditto, ignoring leading whitespace */
! 260: static size_t pending_spaces; /* Spaces to add before next word */
! 261: static int output_in_paragraph=0; /* Any of current para written out yet? */
! 262:
! 263: /* Prototypes */
! 264:
! 265: static void process_named_file (const char *);
! 266: static void process_stream (FILE *, const char *);
! 267: static size_t indent_length (const char *, size_t);
! 268: static int might_be_header (const char *);
! 269: static void new_paragraph (size_t, size_t);
! 270: static void output_word (size_t, size_t, const char *, size_t, size_t);
! 271: static void output_indent (size_t);
! 272: static void center_stream (FILE *, const char *);
! 273: static char * get_line (FILE *, size_t *);
! 274: static void * xrealloc (void *, size_t);
! 275:
! 276: #define XMALLOC(x) xrealloc(0,x)
! 277:
! 278: /* Here is perhaps the right place to mention that this code is
! 279: * all in top-down order. Hence, |main| comes first.
1.1 deraadt 280: */
1.4 millert 281: int
1.10 ! millert 282: main(int argc, char *argv[]) {
! 283: int ch; /* used for |getopt| processing */
! 284:
! 285: /* 1. Grok parameters. */
! 286:
! 287: while ((ch = getopt(argc, argv, "cd:hl:mpst:")) != EOF) switch(ch) {
! 288: case 'c':
! 289: centerP = 1;
! 290: continue;
! 291: case 'd':
! 292: sentence_enders = XMALLOC(strlen(optarg)+1);
! 293: strcpy(sentence_enders, optarg);
! 294: continue;
! 295: case 'l':
! 296: output_tab_width
! 297: = get_positive(optarg, "output tab width must be positive", 1);
! 298: continue;
! 299: case 'm':
! 300: grok_mail_headers = 1;
! 301: continue;
! 302: case 'p':
! 303: allow_indented_paragraphs = 1;
! 304: continue;
! 305: case 's':
! 306: coalesce_spaces_P = 1;
! 307: continue;
! 308: case 't':
! 309: tab_width = get_positive(optarg, "tab width must be positive", 1);
! 310: continue;
! 311: case 'h': default:
! 312: fprintf(stderr,
! 313: "Usage: fmt [-cmps] [-d chars] [-l num] [-t num] [goal [maximum]] [file...]\n"
! 314: "Options: -c " CENTER " each line instead of formatting\n"
! 315: " -d <chars> double-space after <chars> at line end\n"
! 316: " -l <n> turn each <n> spaces at start of line into a tab\n"
! 317: " -m try to make sure mail header lines stay separate\n"
! 318: " -p allow indented paragraphs\n"
! 319: " -s coalesce whitespace inside lines\n"
! 320: " -t <n> have tabs every <n> columns\n");
! 321: exit(ch=='h' ? 0 : EX_USAGE);
! 322: }
! 323: argc -= optind; argv += optind;
! 324:
! 325: /* [ goal [ maximum ] ] */
! 326:
! 327: if (argc>0
! 328: && (goal_length=get_positive(*argv,"goal length must be positive", 0))
! 329: != 0) {
! 330: --argc; ++argv;
! 331: if (argc>0
! 332: && (goal_length=get_positive(*argv,"max length must be positive", 0))
! 333: != 0) {
! 334: if (max_length<goal_length)
! 335: errx(EX_USAGE, "max length must be >= goal length");
! 336: }
! 337: }
! 338: if (goal_length==0) goal_length = 65;
! 339: if (max_length==0) max_length = goal_length+10;
! 340: output_buffer = XMALLOC(max_length+1); /* really needn't be longer */
! 341:
! 342: /* 2. Process files. */
! 343:
! 344: if (argc>0) {
! 345: while (argc-->0) process_named_file(*argv++);
! 346: }
! 347: else {
! 348: process_stream(stdin, "standard input");
! 349: }
! 350:
! 351: /* We're done. */
! 352:
! 353: return n_errors ? EX_NOINPUT : 0;
! 354:
! 355: }
! 356:
! 357: /* Process a single file, given its name.
! 358: */
! 359: static void
! 360: process_named_file(const char *name) {
! 361: FILE *f=fopen(name, "r");
! 362: if (!f) { perror(name); ++n_errors; }
! 363: else {
! 364: process_stream(f, name);
! 365: fclose(f);
! 366: }
! 367: }
! 368:
! 369: /* Types of mail header continuation lines:
! 370: */
! 371: typedef enum {
! 372: hdr_ParagraphStart = -1,
! 373: hdr_NonHeader = 0,
! 374: hdr_Header = 1,
! 375: hdr_Continuation = 2
! 376: } HdrType;
! 377:
! 378: /* Process a stream. This is where the real work happens,
! 379: * except that centering is handled separately.
! 380: */
! 381: static void
! 382: process_stream(FILE *stream, const char *name) {
! 383: size_t last_indent=SILLY; /* how many spaces in last indent? */
! 384: size_t para_line_number=0; /* how many lines already read in this para? */
! 385: size_t first_indent=SILLY; /* indentation of line 0 of paragraph */
! 386: HdrType prev_header_type=hdr_ParagraphStart;
! 387: /* ^-- header_type of previous line; -1 at para start */
! 388: char *line;
! 389: size_t length;
! 390:
! 391: if (centerP) { center_stream(stream, name); return; }
! 392: while ((line=get_line(stream,&length)) != NULL) {
! 393: size_t np=indent_length(line, length);
! 394: { HdrType header_type=hdr_NonHeader;
! 395: if (grok_mail_headers && prev_header_type!=hdr_NonHeader) {
! 396: if (np==0 && might_be_header(line))
! 397: header_type = hdr_Header;
! 398: else if (np>0 && prev_header_type>hdr_NonHeader)
! 399: header_type = hdr_Continuation;
! 400: }
! 401: /* We need a new paragraph if and only if:
! 402: * this line is blank,
! 403: * OR it's a mail header,
! 404: * OR it's not a mail header AND the last line was one,
! 405: * OR the indentation has changed
! 406: * AND the line isn't a mail header continuation line
! 407: * AND this isn't the second line of an indented paragraph.
! 408: */
! 409: if ( length==0
! 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) {
! 421: putchar('\n');
! 422: prev_header_type=hdr_ParagraphStart;
! 423: continue;
! 424: }
! 425: }
! 426: else {
! 427: /* If this is an indented paragraph other than a mail header
! 428: * continuation, set |last_indent|.
! 429: */
! 430: if (np != last_indent && header_type != hdr_Continuation)
! 431: last_indent=np;
! 432: }
! 433: prev_header_type = header_type;
! 434: }
! 435:
! 436: { size_t n=np;
! 437: while (n<length) {
! 438: /* Find word end and count spaces after it */
! 439: size_t word_length=0, space_length=0;
! 440: while (n+word_length < length && line[n+word_length] != ' ')
! 441: ++word_length;
! 442: space_length = word_length;
! 443: while (n+space_length < length && line[n+space_length] == ' ')
! 444: ++space_length;
! 445: /* Send the word to the output machinery. */
! 446: output_word(first_indent, last_indent,
! 447: line+n, word_length, space_length-word_length);
! 448: n += space_length;
! 449: }
! 450: }
! 451: ++para_line_number;
! 452: }
! 453: new_paragraph(output_in_paragraph ? last_indent : first_indent, 0);
! 454: if (ferror(stream)) { perror(name); ++n_errors; }
! 455: }
! 456:
! 457: /* How long is the indent on this line?
! 458: */
! 459: static size_t
! 460: indent_length(const char *line, size_t length) {
! 461: size_t n=0;
! 462: while (n<length && *line++ == ' ') ++n;
! 463: return n;
! 464: }
! 465:
! 466: /* Might this line be a mail header?
! 467: * We deem a line to be a possible header if it matches the
! 468: * Perl regexp /^[A-Z][-A-Za-z0-9]*:\s/. This is *not* the same
! 469: * as in RFC whatever-number-it-is; we want to be gratuitously
! 470: * conservative to avoid mangling ordinary civilised text.
! 471: */
! 472: static int
! 473: might_be_header(const char *line) {
! 474: if (!isupper(*line++)) return 0;
! 475: while (*line && (isalnum(*line) || *line=='-')) ++line;
! 476: return (*line==':' && isspace(line[1]));
! 477: }
! 478:
! 479: /* Begin a new paragraph with an indent of |indent| spaces.
! 480: */
! 481: static void
! 482: new_paragraph(size_t old_indent, size_t indent) {
! 483: if (x0) {
! 484: if (old_indent>0) output_indent(old_indent);
! 485: fwrite(output_buffer, 1, x0, stdout);
! 486: putchar('\n');
! 487: }
! 488: x=indent; x0=0; pending_spaces=0;
! 489: output_in_paragraph = 0;
! 490: }
! 491:
! 492: /* Output spaces or tabs for leading indentation.
! 493: */
! 494: static void
! 495: output_indent(size_t n_spaces) {
! 496: if (output_tab_width) {
! 497: while (n_spaces >= output_tab_width) {
! 498: putchar('\t');
! 499: n_spaces -= output_tab_width;
! 500: }
! 501: }
! 502: while (n_spaces-- > 0) putchar(' ');
! 503: }
! 504:
! 505: /* Output a single word, or add it to the buffer.
! 506: * indent0 and indent1 are the indents to use on the first and subsequent
! 507: * lines of a paragraph. They'll often be the same, of course.
! 508: */
! 509: static void
! 510: output_word(size_t indent0, size_t indent1, const char *word, size_t length, size_t spaces) {
! 511: size_t new_x = x+pending_spaces+length;
! 512: size_t indent = output_in_paragraph ? indent1 : indent0;
! 513:
! 514: /* If either |spaces==0| (at end of line) or |coalesce_spaces_P|
! 515: * (squashing internal whitespace), then add just one space;
! 516: * except that if the last character was a sentence-ender we
! 517: * actually add two spaces.
! 518: */
! 519: if (coalesce_spaces_P || spaces==0)
! 520: spaces = strchr(sentence_enders, word[length-1]) ? 2 : 1;
! 521:
! 522: if (new_x<=goal_length) {
! 523: /* After adding the word we still aren't at the goal length,
! 524: * so clearly we add it to the buffer rather than outputing it.
! 525: */
! 526: memset(output_buffer+x0, ' ', pending_spaces);
! 527: x0 += pending_spaces; x += pending_spaces;
! 528: memcpy(output_buffer+x0, word, length);
! 529: x0 += length; x += length;
! 530: pending_spaces = spaces;
! 531: }
! 532: else {
! 533: /* Adding the word takes us past the goal. Print the line-so-far,
! 534: * and the word too iff either (1) the lsf is empty or (2) that
! 535: * makes us nearer the goal but doesn't take us over the limit,
! 536: * or (3) the word on its own takes us over the limit.
! 537: * In case (3) we put a newline in between.
! 538: */
! 539: if (indent>0) output_indent(indent);
! 540: fwrite(output_buffer, 1, x0, stdout);
! 541: if (x0==0 || (new_x <= max_length && new_x-goal_length <= goal_length-x)) {
! 542: printf("%*s", pending_spaces, "");
! 543: goto write_out_word;
! 544: }
! 545: else {
! 546: /* If the word takes us over the limit on its own, just
! 547: * spit it out and don't bother buffering it.
! 548: */
! 549: if (indent+length > max_length) {
! 550: putchar('\n');
! 551: if (indent>0) output_indent(indent);
! 552: write_out_word:
! 553: fwrite(word, 1, length, stdout);
! 554: x0 = 0; x = indent1; pending_spaces = 0;
! 555: }
! 556: else {
! 557: memcpy(output_buffer, word, length);
! 558: x0 = length; x = length+indent1; pending_spaces = spaces;
! 559: }
! 560: }
! 561: putchar('\n');
! 562: output_in_paragraph = 1;
! 563: }
! 564: }
! 565:
! 566: /* Process a stream, but just center its lines rather than trying to
! 567: * format them neatly.
! 568: */
! 569: static void
! 570: center_stream(FILE *stream, const char *name) {
! 571: char *line;
! 572: size_t length;
! 573: while ((line=get_line(stream, &length)) != 0) {
! 574: size_t l=length;
! 575: while (l>0 && isspace(*line)) { ++line; --l; }
! 576: length=l;
! 577: while (l<goal_length) { putchar(' '); l+=2; }
! 578: fwrite(line, 1, length, stdout);
! 579: putchar('\n');
! 580: }
! 581: if (ferror(stream)) { perror(name); ++n_errors; }
! 582: }
! 583:
! 584: /* Get a single line from a stream. Expand tabs, strip control
! 585: * characters and trailing whitespace, and handle backspaces.
! 586: * Return the address of the buffer containing the line, and
! 587: * put the length of the line in |lengthp|.
! 588: * This can cope with arbitrarily long lines, and with lines
! 589: * without terminating \n.
! 590: * If there are no characters left or an error happens, we
! 591: * return 0.
! 592: * Don't confuse |spaces_pending| here with the global
! 593: * |pending_spaces|.
! 594: */
! 595: static char *
! 596: get_line(FILE *stream, size_t *lengthp) {
! 597: static char *buf=NULL;
! 598: static size_t length=0;
! 599: size_t len=0;
! 600: int ch;
! 601: size_t spaces_pending=0;
! 602:
! 603: if (buf==NULL) { length=100; buf=XMALLOC(length); }
! 604: while ((ch=getc(stream)) != '\n' && ch != EOF) {
! 605: if (ch==' ') ++spaces_pending;
! 606: else if (isprint(ch)) {
! 607: while (len+spaces_pending >= length) {
! 608: length*=2; buf=xrealloc(buf, length);
! 609: }
! 610: while (spaces_pending > 0) { --spaces_pending; buf[len++]=' '; }
! 611: buf[len++] = ch;
! 612: }
! 613: else if (ch=='\t')
! 614: spaces_pending += tab_width - (len+spaces_pending)%tab_width;
! 615: else if (ch=='\b') { if (len) --len; }
! 616: }
! 617: *lengthp=len;
! 618: return (len>0 || ch!=EOF) ? buf : 0;
! 619: }
! 620:
! 621: /* (Re)allocate some memory, exiting with an error if we can't.
! 622: */
! 623: static void *
! 624: xrealloc(void *ptr, size_t nbytes) {
! 625: void *p = realloc(ptr, nbytes);
! 626: if (p == NULL) errx(EX_OSERR, "out of memory");
! 627: return p;
1.1 deraadt 628: }
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