Annotation of src/usr.bin/fmt/fmt.c, Revision 1.11
1.11 ! millert 1: /* $OpenBSD: fmt.c,v 1.10 1998/04/25 23:02:28 millert Exp $ */
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[] =
1.11 ! millert 171: "$OpenBSD: fmt.c,v 1.10 1998/04/25 23:02:28 millert Exp $";
1.10 millert 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:
1.11 ! millert 287: while ((ch = getopt(argc, argv, "cd:hl:mpst:")) != -1) switch(ch) {
1.10 millert 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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