1 /* GNU fmt -- simple text formatter.
2 Copyright (C) 1994-2003 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2, or (at your option)
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software Foundation,
16 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
18 /* Written by Ross Paterson <rap@doc.ic.ac.uk>. */
22 #include <sys/types.h>
25 /* Redefine. Otherwise, systems (Unicos for one) with headers that define
26 it to be a type get syntax errors for the variable declaration below. */
27 #define word unused_word_type
34 /* The official name of this program (e.g., no `g' prefix). */
35 #define PROGRAM_NAME "fmt"
37 #define WRITTEN_BY _("Written by Ross Paterson.")
39 /* The following parameters represent the program's idea of what is
40 "best". Adjust to taste, subject to the caveats given. */
42 /* Default longest permitted line length (max_width). */
45 /* Prefer lines to be LEEWAY % shorter than the maximum width, giving
46 room for optimization. */
49 /* The default secondary indent of tagged paragraph used for unindented
50 one-line paragraphs not preceded by any multi-line paragraphs. */
53 /* Costs and bonuses are expressed as the equivalent departure from the
54 optimal line length, multiplied by 10. e.g. assigning something a
55 cost of 50 means that it is as bad as a line 5 characters too short
56 or too long. The definition of SHORT_COST(n) should not be changed.
57 However, EQUIV(n) may need tuning. */
61 #define MAXCOST TYPE_MAXIMUM (COST)
63 #define SQR(n) ((n) * (n))
64 #define EQUIV(n) SQR ((COST) (n))
66 /* Cost of a filled line n chars longer or shorter than best_width. */
67 #define SHORT_COST(n) EQUIV ((n) * 10)
69 /* Cost of the difference between adjacent filled lines. */
70 #define RAGGED_COST(n) (SHORT_COST (n) / 2)
72 /* Basic cost per line. */
73 #define LINE_COST EQUIV (70)
75 /* Cost of breaking a line after the first word of a sentence, where
76 the length of the word is N. */
77 #define WIDOW_COST(n) (EQUIV (200) / ((n) + 2))
79 /* Cost of breaking a line before the last word of a sentence, where
80 the length of the word is N. */
81 #define ORPHAN_COST(n) (EQUIV (150) / ((n) + 2))
83 /* Bonus for breaking a line at the end of a sentence. */
84 #define SENTENCE_BONUS EQUIV (50)
86 /* Cost of breaking a line after a period not marking end of a sentence.
87 With the definition of sentence we are using (borrowed from emacs, see
88 get_line()) such a break would then look like a sentence break. Hence
89 we assign a very high cost -- it should be avoided unless things are
91 #define NOBREAK_COST EQUIV (600)
93 /* Bonus for breaking a line before open parenthesis. */
94 #define PAREN_BONUS EQUIV (40)
96 /* Bonus for breaking a line after other punctuation. */
97 #define PUNCT_BONUS EQUIV(40)
99 /* Credit for breaking a long paragraph one line later. */
100 #define LINE_CREDIT EQUIV(3)
102 /* Size of paragraph buffer, in words and characters. Longer paragraphs
103 are handled neatly (cf. flush_paragraph()), so there's little to gain
104 by making these larger. */
105 #define MAXWORDS 1000
106 #define MAXCHARS 5000
108 /* Extra ctype(3)-style macros. */
110 #define isopen(c) (strchr ("([`'\"", c) != NULL)
111 #define isclose(c) (strchr (")]'\"", c) != NULL)
112 #define isperiod(c) (strchr (".?!", c) != NULL)
114 /* Size of a tab stop, for expansion on input and re-introduction on
118 /* Miscellaneous definitions. */
125 /* Word descriptor structure. */
127 typedef struct Word WORD;
132 /* Static attributes determined during input. */
134 const char *text; /* the text of the word */
135 int length; /* length of this word */
136 int space; /* the size of the following space */
137 unsigned int paren:1; /* starts with open paren */
138 unsigned int period:1; /* ends in [.?!])* */
139 unsigned int punct:1; /* ends in punctuation */
140 unsigned int final:1; /* end of sentence */
142 /* The remaining fields are computed during the optimization. */
144 int line_length; /* length of the best line starting here */
145 COST best_cost; /* cost of best paragraph starting here */
146 WORD *next_break; /* break which achieves best_cost */
149 /* Forward declarations. */
151 static void set_prefix (char *p);
152 static void fmt (FILE *f);
153 static bool get_paragraph (FILE *f);
154 static int get_line (FILE *f, int c);
155 static int get_prefix (FILE *f);
156 static int get_space (FILE *f, int c);
157 static int copy_rest (FILE *f, int c);
158 static bool same_para (int c);
159 static void flush_paragraph (void);
160 static void fmt_paragraph (void);
161 static void check_punctuation (WORD *w);
162 static COST base_cost (WORD *this);
163 static COST line_cost (WORD *next, int len);
164 static void put_paragraph (WORD *finish);
165 static void put_line (WORD *w, int indent);
166 static void put_word (WORD *w);
167 static void put_space (int space);
169 /* The name this program was run with. */
170 const char *program_name;
174 /* If TRUE, first 2 lines may have different indent (default FALSE). */
177 /* If TRUE, first 2 lines _must_ have different indent (default FALSE). */
180 /* If TRUE, each line is a paragraph on its own (default FALSE). */
183 /* If TRUE, don't preserve inter-word spacing (default FALSE). */
186 /* Prefix minus leading and trailing spaces (default ""). */
187 static const char *prefix;
189 /* User-supplied maximum line width (default WIDTH). The only output
190 lines longer than this will each comprise a single word. */
191 static int max_width;
193 /* Values derived from the option values. */
195 /* The length of prefix minus leading space. */
196 static int prefix_full_length;
198 /* The length of the leading space trimmed from the prefix. */
199 static int prefix_lead_space;
201 /* The length of prefix minus leading and trailing space. */
202 static int prefix_length;
204 /* The preferred width of text lines, set to LEEWAY % less than max_width. */
205 static int best_width;
207 /* Dynamic variables. */
209 /* Start column of the character most recently read from the input file. */
210 static int in_column;
212 /* Start column of the next character to be written to stdout. */
213 static int out_column;
215 /* Space for the paragraph text -- longer paragraphs are handled neatly
216 (cf. flush_paragraph()). */
217 static char parabuf[MAXCHARS];
219 /* A pointer into parabuf, indicating the first unused character position. */
222 /* The words of a paragraph -- longer paragraphs are handled neatly
223 (cf. flush_paragraph()). */
224 static WORD word[MAXWORDS];
226 /* A pointer into the above word array, indicating the first position
227 after the last complete word. Sometimes it will point at an incomplete
229 static WORD *word_limit;
231 /* If TRUE, current input file contains tab characters, and so tabs can be
232 used for white space on output. */
235 /* Space before trimmed prefix on each line of the current paragraph. */
236 static int prefix_indent;
238 /* Indentation of the first line of the current paragraph. */
239 static int first_indent;
241 /* Indentation of other lines of the current paragraph */
242 static int other_indent;
244 /* To detect the end of a paragraph, we need to look ahead to the first
245 non-blank character after the prefix on the next line, or the first
246 character on the following line that failed to match the prefix.
247 We can reconstruct the lookahead from that character (next_char), its
248 position on the line (in_column) and the amount of space before the
249 prefix (next_prefix_indent). See get_paragraph() and copy_rest(). */
251 /* The last character read from the input file. */
252 static int next_char;
254 /* The space before the trimmed prefix (or part of it) on the next line
255 after the current paragraph. */
256 static int next_prefix_indent;
258 /* If nonzero, the length of the last line output in the current
259 paragraph, used to charge for raggedness at the split point for long
260 paragraphs chosen by fmt_paragraph(). */
261 static int last_line_length;
267 fprintf (stderr, _("Try `%s --help' for more information.\n"),
271 printf (_("Usage: %s [-DIGITS] [OPTION]... [FILE]...\n"), program_name);
273 Reformat each paragraph in the FILE(s), writing to standard output.\n\
274 If no FILE or if FILE is `-', read standard input.\n\
278 Mandatory arguments to long options are mandatory for short options too.\n\
281 -c, --crown-margin preserve indentation of first two lines\n\
282 -p, --prefix=STRING combine only lines having STRING as prefix\n\
283 -s, --split-only split long lines, but do not refill\n\
287 -t, --tagged-paragraph indentation of first line different from second\n\
288 -u, --uniform-spacing one space between words, two after sentences\n\
289 -w, --width=WIDTH maximum line width (default of 75 columns)\n\
291 fputs (HELP_OPTION_DESCRIPTION, stdout);
292 fputs (VERSION_OPTION_DESCRIPTION, stdout);
295 With no FILE, or when FILE is -, read standard input.\n"),
297 printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
299 exit (status == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
302 /* Decode options and launch execution. */
304 static const struct option long_options[] =
306 {"crown-margin", no_argument, NULL, 'c'},
307 {"prefix", required_argument, NULL, 'p'},
308 {"split-only", no_argument, NULL, 's'},
309 {"tagged-paragraph", no_argument, NULL, 't'},
310 {"uniform-spacing", no_argument, NULL, 'u'},
311 {"width", required_argument, NULL, 'w'},
312 {GETOPT_HELP_OPTION_DECL},
313 {GETOPT_VERSION_OPTION_DECL},
318 main (register int argc, register char **argv)
323 initialize_main (&argc, &argv);
324 program_name = argv[0];
325 setlocale (LC_ALL, "");
326 bindtextdomain (PACKAGE, LOCALEDIR);
327 textdomain (PACKAGE);
329 atexit (close_stdout);
331 crown = tagged = split = uniform = FALSE;
334 prefix_length = prefix_lead_space = prefix_full_length = 0;
336 if (argc > 1 && argv[1][0] == '-' && ISDIGIT (argv[1][1]))
338 const char *s = argv[1] + 1;
340 /* Old option syntax; a dash followed by one or more digits.
341 Move past the number. */
342 for (; ISDIGIT (*s); ++s)
344 int old_max = max_width;
345 max_width = max_width * 10 + *s - '0';
346 if (INT_MAX / 10 < old_max || max_width < old_max)
351 error (EXIT_FAILURE, 0, _("invalid width option: %s"),
354 /* Make the options we just parsed invisible to getopt. */
360 while ((optchar = getopt_long (argc, argv, "0123456789cstuw:p:",
366 if (ISDIGIT (optchar))
367 error (0, 0, _("invalid option -- %c; -WIDTH is recognized\
368 only when it is the first\noption; use -w N instead"),
370 usage (EXIT_FAILURE);
391 if (xstrtol (optarg, NULL, 10, &tmp_long, "") != LONGINT_OK
392 || tmp_long <= 0 || tmp_long > INT_MAX)
393 error (EXIT_FAILURE, 0, _("invalid width: %s"), quote (optarg));
394 max_width = (int) tmp_long;
402 case_GETOPT_HELP_CHAR;
404 case_GETOPT_VERSION_CHAR (PROGRAM_NAME, WRITTEN_BY);
408 best_width = max_width * (2 * (100 - LEEWAY) + 1) / 200;
415 for (; optind < argc; optind++)
417 char *file = argv[optind];
418 if (STREQ (file, "-"))
423 in_stream = fopen (file, "r");
424 if (in_stream != NULL)
427 if (fclose (in_stream) == EOF)
429 error (0, errno, "%s", file);
435 error (0, errno, _("cannot open %s for reading"),
443 exit (fail ? EXIT_FAILURE : EXIT_SUCCESS);
446 /* Trim space from the front and back of the string P, yielding the prefix,
447 and record the lengths of the prefix and the space trimmed. */
450 set_prefix (register char *p)
454 prefix_lead_space = 0;
461 prefix_full_length = strlen (p);
462 s = p + prefix_full_length;
463 while (s > p && s[-1] == ' ')
466 prefix_length = s - p;
469 /* read file F and send formatted output to stdout. */
476 next_char = get_prefix (f);
477 while (get_paragraph (f))
480 put_paragraph (word_limit);
484 /* Set the global variable `other_indent' according to SAME_PARAGRAPH
485 and other global variables. */
488 set_other_indent (bool same_paragraph)
491 other_indent = first_indent;
494 other_indent = (same_paragraph ? in_column : first_indent);
498 if (same_paragraph && in_column != first_indent)
500 other_indent = in_column;
503 /* Only one line: use the secondary indent from last time if it
504 splits, or 0 if there have been no multi-line paragraphs in the
505 input so far. But if these rules make the two indents the same,
506 pick a new secondary indent. */
508 else if (other_indent == first_indent)
509 other_indent = first_indent == 0 ? DEF_INDENT : 0;
513 other_indent = first_indent;
517 /* Read a paragraph from input file F. A paragraph consists of a
518 maximal number of non-blank (excluding any prefix) lines subject to:
519 * In split mode, a paragraph is a single non-blank line.
520 * In crown mode, the second and subsequent lines must have the
521 same indentation, but possibly different from the indent of the
523 * Tagged mode is similar, but the first and second lines must have
524 different indentations.
525 * Otherwise, all lines of a paragraph must have the same indent.
526 If a prefix is in effect, it must be present at the same indent for
527 each line in the paragraph.
529 Return FALSE if end-of-file was encountered before the start of a
530 paragraph, else TRUE. */
533 get_paragraph (FILE *f)
537 last_line_length = 0;
540 /* Scan (and copy) blank lines, and lines not introduced by the prefix. */
542 while (c == '\n' || c == EOF
543 || next_prefix_indent < prefix_lead_space
544 || in_column < next_prefix_indent + prefix_full_length)
546 c = copy_rest (f, c);
556 /* Got a suitable first line for a paragraph. */
558 prefix_indent = next_prefix_indent;
559 first_indent = in_column;
563 set_other_indent (same_para (c));
565 /* Read rest of paragraph (unless split is specified). */
576 { /* for each line till the end of the para */
579 while (same_para (c) && in_column == other_indent);
584 if (same_para (c) && in_column != first_indent)
587 { /* for each line till the end of the para */
590 while (same_para (c) && in_column == other_indent);
595 while (same_para (c) && in_column == other_indent)
598 (word_limit - 1)->period = (word_limit - 1)->final = TRUE;
603 /* Copy to the output a line that failed to match the prefix, or that
604 was blank after the prefix. In the former case, C is the character
605 that failed to match the prefix. In the latter, C is \n or EOF.
606 Return the character (\n or EOF) ending the line. */
609 copy_rest (FILE *f, register int c)
611 register const char *s;
614 if (in_column > next_prefix_indent && c != '\n' && c != EOF)
616 put_space (next_prefix_indent);
617 for (s = prefix; out_column != in_column && *s; out_column++)
618 putchar (*(unsigned char *)s++);
619 put_space (in_column - out_column);
621 while (c != '\n' && c != EOF)
629 /* Return TRUE if a line whose first non-blank character after the
630 prefix (if any) is C could belong to the current paragraph,
634 same_para (register int c)
636 return (next_prefix_indent == prefix_indent
637 && in_column >= next_prefix_indent + prefix_full_length
638 && c != '\n' && c != EOF);
641 /* Read a line from input file F, given first non-blank character C
642 after the prefix, and the following indent, and break it into words.
643 A word is a maximal non-empty string of non-white characters. A word
644 ending in [.?!]["')\]]* and followed by end-of-line or at least two
645 spaces ends a sentence, as in emacs.
647 Return the first non-blank character of the next line. */
650 get_line (FILE *f, register int c)
653 register char *end_of_parabuf;
654 register WORD *end_of_word;
656 end_of_parabuf = ¶buf[MAXCHARS];
657 end_of_word = &word[MAXWORDS - 2];
660 { /* for each word in a line */
664 word_limit->text = wptr;
667 if (wptr == end_of_parabuf)
669 set_other_indent (true);
675 while (c != EOF && !ISSPACE (c));
676 in_column += word_limit->length = wptr - word_limit->text;
677 check_punctuation (word_limit);
679 /* Scan inter-word space. */
682 c = get_space (f, c);
683 word_limit->space = in_column - start;
684 word_limit->final = (c == EOF
685 || (word_limit->period
686 && (c == '\n' || word_limit->space > 1)));
687 if (c == '\n' || c == EOF || uniform)
688 word_limit->space = word_limit->final ? 2 : 1;
689 if (word_limit == end_of_word)
691 set_other_indent (true);
699 return get_prefix (f);
702 /* Read a prefix from input file F. Return either first non-matching
703 character, or first non-blank character after the prefix. */
711 c = get_space (f, getc (f));
712 if (prefix_length == 0)
713 next_prefix_indent = prefix_lead_space < in_column ?
714 prefix_lead_space : in_column;
718 next_prefix_indent = in_column;
719 for (p = prefix; *p != '\0'; p++)
721 if (c != *(unsigned char *)p)
726 c = get_space (f, c);
731 /* Read blank characters from input file F, starting with C, and keeping
732 in_column up-to-date. Return first non-blank character. */
735 get_space (FILE *f, register int c)
744 in_column = (in_column / TABWIDTH + 1) * TABWIDTH;
752 /* Set extra fields in word W describing any attached punctuation. */
755 check_punctuation (register WORD *w)
757 const unsigned char *start, *finish;
759 start = (unsigned char *) w->text;
760 finish = start + (w->length - 1);
761 w->paren = isopen (*start);
762 w->punct = ISPUNCT (*finish);
763 while (isclose (*finish) && finish > start)
765 w->period = isperiod (*finish);
768 /* Flush part of the paragraph to make room. This function is called on
769 hitting the limit on the number of words or characters. */
772 flush_paragraph (void)
779 /* In the special case where it's all one word, just flush it. */
781 if (word_limit == word)
783 printf ("%*s", (int) (wptr - parabuf), parabuf);
789 - format what you have so far as a paragraph,
790 - find a low-cost line break near the end,
792 - make that the start of the paragraph. */
796 /* Choose a good split point. */
798 split_point = word_limit;
799 best_break = MAXCOST;
800 for (w = word->next_break; w != word_limit; w = w->next_break)
802 if (w->best_cost - w->next_break->best_cost < best_break)
805 best_break = w->best_cost - w->next_break->best_cost;
807 if (best_break <= MAXCOST - LINE_CREDIT)
808 best_break += LINE_CREDIT;
810 put_paragraph (split_point);
812 /* Copy text of words down to start of parabuf -- we use memmove because
813 the source and target may overlap. */
815 memmove (parabuf, split_point->text, (size_t) (wptr - split_point->text));
816 shift = split_point->text - parabuf;
819 /* Adjust text pointers. */
821 for (w = split_point; w <= word_limit; w++)
824 /* Copy words from split_point down to word -- we use memmove because
825 the source and target may overlap. */
827 memmove ((char *) word, (char *) split_point,
828 (word_limit - split_point + 1) * sizeof (WORD));
829 word_limit -= split_point - word;
832 /* Compute the optimal formatting for the whole paragraph by computing
833 and remembering the optimal formatting for each suffix from the empty
834 one to the whole paragraph. */
839 register WORD *start, *w;
841 register COST wcost, best;
844 word_limit->best_cost = 0;
845 saved_length = word_limit->length;
846 word_limit->length = max_width; /* sentinel */
848 for (start = word_limit - 1; start >= word; start--)
851 len = start == word ? first_indent : other_indent;
853 /* At least one word, however long, in the line. */
861 /* Consider breaking before w. */
863 wcost = line_cost (w, len) + w->best_cost;
864 if (start == word && last_line_length > 0)
865 wcost += RAGGED_COST (len - last_line_length);
869 start->next_break = w;
870 start->line_length = len;
873 /* This is a kludge to keep us from computing `len' as the
874 sum of the sentinel length and some non-zero number.
875 Since the sentinel w->length may be INT_MAX, adding
876 to that would give a negative result. */
880 len += (w - 1)->space + w->length; /* w > start >= word */
882 while (len < max_width);
883 start->best_cost = best + base_cost (start);
886 word_limit->length = saved_length;
889 /* Return the constant component of the cost of breaking before the
893 base_cost (register WORD *this)
901 if ((this - 1)->period)
903 if ((this - 1)->final)
904 cost -= SENTENCE_BONUS;
906 cost += NOBREAK_COST;
908 else if ((this - 1)->punct)
910 else if (this > word + 1 && (this - 2)->final)
911 cost += WIDOW_COST ((this - 1)->length);
916 else if (this->final)
917 cost += ORPHAN_COST (this->length);
922 /* Return the component of the cost of breaking before word NEXT that
923 depends on LEN, the length of the line beginning there. */
926 line_cost (register WORD *next, register int len)
931 if (next == word_limit)
933 n = best_width - len;
934 cost = SHORT_COST (n);
935 if (next->next_break != word_limit)
937 n = len - next->line_length;
938 cost += RAGGED_COST (n);
943 /* Output to stdout a paragraph from word up to (but not including)
944 FINISH, which must be in the next_break chain from word. */
947 put_paragraph (register WORD *finish)
951 put_line (word, first_indent);
952 for (w = word->next_break; w != finish; w = w->next_break)
953 put_line (w, other_indent);
956 /* Output to stdout the line beginning with word W, beginning in column
957 INDENT, including the prefix (if any). */
960 put_line (register WORD *w, int indent)
962 register WORD *endline;
965 put_space (prefix_indent);
966 fputs (prefix, stdout);
967 out_column += prefix_length;
968 put_space (indent - out_column);
970 endline = w->next_break - 1;
971 for (; w != endline; w++)
974 put_space (w->space);
977 last_line_length = out_column;
981 /* Output to stdout the word W. */
984 put_word (register WORD *w)
986 register const char *s;
990 for (n = w->length; n != 0; n--)
992 out_column += w->length;
995 /* Output to stdout SPACE spaces, or equivalent tabs. */
998 put_space (int space)
1000 register int space_target, tab_target;
1002 space_target = out_column + space;
1005 tab_target = space_target / TABWIDTH * TABWIDTH;
1006 if (out_column + 1 < tab_target)
1007 while (out_column < tab_target)
1010 out_column = (out_column / TABWIDTH + 1) * TABWIDTH;
1013 while (out_column < space_target)