1 /* GNU fmt -- simple text formatter.
2 Copyright (C) 1994-2006, 2008-2010 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 3 of the License, or
7 (at your option) any later version.
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, see <http://www.gnu.org/licenses/>. */
17 /* Written by Ross Paterson <rap@doc.ic.ac.uk>. */
21 #include <sys/types.h>
24 /* Redefine. Otherwise, systems (Unicos for one) with headers that define
25 it to be a type get syntax errors for the variable declaration below. */
26 #define word unused_word_type
33 /* The official name of this program (e.g., no `g' prefix). */
34 #define PROGRAM_NAME "fmt"
36 #define AUTHORS proper_name ("Ross Paterson")
38 /* The following parameters represent the program's idea of what is
39 "best". Adjust to taste, subject to the caveats given. */
41 /* Default longest permitted line length (max_width). */
44 /* Prefer lines to be LEEWAY % shorter than the maximum width, giving
45 room for optimization. */
48 /* The default secondary indent of tagged paragraph used for unindented
49 one-line paragraphs not preceded by any multi-line paragraphs. */
52 /* Costs and bonuses are expressed as the equivalent departure from the
53 optimal line length, multiplied by 10. e.g. assigning something a
54 cost of 50 means that it is as bad as a line 5 characters too short
55 or too long. The definition of SHORT_COST(n) should not be changed.
56 However, EQUIV(n) may need tuning. */
58 /* FIXME: "fmt" misbehaves given large inputs or options. One
59 possible workaround for part of the problem is to change COST to be
60 a floating-point type. There are other problems besides COST,
61 though; see MAXWORDS below. */
63 typedef long int COST
;
65 #define MAXCOST TYPE_MAXIMUM (COST)
67 #define SQR(n) ((n) * (n))
68 #define EQUIV(n) SQR ((COST) (n))
70 /* Cost of a filled line n chars longer or shorter than best_width. */
71 #define SHORT_COST(n) EQUIV ((n) * 10)
73 /* Cost of the difference between adjacent filled lines. */
74 #define RAGGED_COST(n) (SHORT_COST (n) / 2)
76 /* Basic cost per line. */
77 #define LINE_COST EQUIV (70)
79 /* Cost of breaking a line after the first word of a sentence, where
80 the length of the word is N. */
81 #define WIDOW_COST(n) (EQUIV (200) / ((n) + 2))
83 /* Cost of breaking a line before the last word of a sentence, where
84 the length of the word is N. */
85 #define ORPHAN_COST(n) (EQUIV (150) / ((n) + 2))
87 /* Bonus for breaking a line at the end of a sentence. */
88 #define SENTENCE_BONUS EQUIV (50)
90 /* Cost of breaking a line after a period not marking end of a sentence.
91 With the definition of sentence we are using (borrowed from emacs, see
92 get_line()) such a break would then look like a sentence break. Hence
93 we assign a very high cost -- it should be avoided unless things are
95 #define NOBREAK_COST EQUIV (600)
97 /* Bonus for breaking a line before open parenthesis. */
98 #define PAREN_BONUS EQUIV (40)
100 /* Bonus for breaking a line after other punctuation. */
101 #define PUNCT_BONUS EQUIV(40)
103 /* Credit for breaking a long paragraph one line later. */
104 #define LINE_CREDIT EQUIV(3)
106 /* Size of paragraph buffer, in words and characters. Longer paragraphs
107 are handled neatly (cf. flush_paragraph()), so long as these values
108 are considerably greater than required by the width. These values
109 cannot be extended indefinitely: doing so would run into size limits
110 and/or cause more overflows in cost calculations. FIXME: Remove these
113 #define MAXWORDS 1000
114 #define MAXCHARS 5000
116 /* Extra ctype(3)-style macros. */
118 #define isopen(c) (strchr ("([`'\"", c) != NULL)
119 #define isclose(c) (strchr (")]'\"", c) != NULL)
120 #define isperiod(c) (strchr (".?!", c) != NULL)
122 /* Size of a tab stop, for expansion on input and re-introduction on
126 /* Word descriptor structure. */
128 typedef struct Word WORD
;
133 /* Static attributes determined during input. */
135 const char *text
; /* the text of the word */
136 int length
; /* length of this word */
137 int space
; /* the size of the following space */
138 unsigned int paren
:1; /* starts with open paren */
139 unsigned int period
:1; /* ends in [.?!])* */
140 unsigned int punct
:1; /* ends in punctuation */
141 unsigned int final
:1; /* end of sentence */
143 /* The remaining fields are computed during the optimization. */
145 int line_length
; /* length of the best line starting here */
146 COST best_cost
; /* cost of best paragraph starting here */
147 WORD
*next_break
; /* break which achieves best_cost */
150 /* Forward declarations. */
152 static void set_prefix (char *p
);
153 static void fmt (FILE *f
);
154 static bool get_paragraph (FILE *f
);
155 static int get_line (FILE *f
, int c
);
156 static int get_prefix (FILE *f
);
157 static int get_space (FILE *f
, int c
);
158 static int copy_rest (FILE *f
, int c
);
159 static bool same_para (int c
);
160 static void flush_paragraph (void);
161 static void fmt_paragraph (void);
162 static void check_punctuation (WORD
*w
);
163 static COST
base_cost (WORD
*this);
164 static COST
line_cost (WORD
*next
, int len
);
165 static void put_paragraph (WORD
*finish
);
166 static void put_line (WORD
*w
, int indent
);
167 static void put_word (WORD
*w
);
168 static void put_space (int space
);
172 /* If true, first 2 lines may have different indent (default false). */
175 /* If true, first 2 lines _must_ have different indent (default false). */
178 /* If true, each line is a paragraph on its own (default false). */
181 /* If true, don't preserve inter-word spacing (default false). */
184 /* Prefix minus leading and trailing spaces (default ""). */
185 static const char *prefix
;
187 /* User-supplied maximum line width (default WIDTH). The only output
188 lines longer than this will each comprise a single word. */
189 static int max_width
;
191 /* Values derived from the option values. */
193 /* The length of prefix minus leading space. */
194 static int prefix_full_length
;
196 /* The length of the leading space trimmed from the prefix. */
197 static int prefix_lead_space
;
199 /* The length of prefix minus leading and trailing space. */
200 static int prefix_length
;
202 /* The preferred width of text lines, set to LEEWAY % less than max_width. */
203 static int best_width
;
205 /* Dynamic variables. */
207 /* Start column of the character most recently read from the input file. */
208 static int in_column
;
210 /* Start column of the next character to be written to stdout. */
211 static int out_column
;
213 /* Space for the paragraph text -- longer paragraphs are handled neatly
214 (cf. flush_paragraph()). */
215 static char parabuf
[MAXCHARS
];
217 /* A pointer into parabuf, indicating the first unused character position. */
220 /* The words of a paragraph -- longer paragraphs are handled neatly
221 (cf. flush_paragraph()). */
222 static WORD word
[MAXWORDS
];
224 /* A pointer into the above word array, indicating the first position
225 after the last complete word. Sometimes it will point at an incomplete
227 static WORD
*word_limit
;
229 /* If true, current input file contains tab characters, and so tabs can be
230 used for white space on output. */
233 /* Space before trimmed prefix on each line of the current paragraph. */
234 static int prefix_indent
;
236 /* Indentation of the first line of the current paragraph. */
237 static int first_indent
;
239 /* Indentation of other lines of the current paragraph */
240 static int other_indent
;
242 /* To detect the end of a paragraph, we need to look ahead to the first
243 non-blank character after the prefix on the next line, or the first
244 character on the following line that failed to match the prefix.
245 We can reconstruct the lookahead from that character (next_char), its
246 position on the line (in_column) and the amount of space before the
247 prefix (next_prefix_indent). See get_paragraph() and copy_rest(). */
249 /* The last character read from the input file. */
250 static int next_char
;
252 /* The space before the trimmed prefix (or part of it) on the next line
253 after the current paragraph. */
254 static int next_prefix_indent
;
256 /* If nonzero, the length of the last line output in the current
257 paragraph, used to charge for raggedness at the split point for long
258 paragraphs chosen by fmt_paragraph(). */
259 static int last_line_length
;
264 if (status
!= EXIT_SUCCESS
)
265 fprintf (stderr
, _("Try `%s --help' for more information.\n"),
269 printf (_("Usage: %s [-WIDTH] [OPTION]... [FILE]...\n"), program_name
);
271 Reformat each paragraph in the FILE(s), writing to standard output.\n\
272 The option -WIDTH is an abbreviated form of --width=DIGITS.\n\
276 Mandatory arguments to long options are mandatory for short options too.\n\
279 -c, --crown-margin preserve indentation of first two lines\n\
280 -p, --prefix=STRING reformat only lines beginning with STRING,\n\
281 reattaching the prefix to reformatted lines\n\
282 -s, --split-only split long lines, but do not refill\n\
286 -t, --tagged-paragraph indentation of first line different from second\n\
287 -u, --uniform-spacing one space between words, two after sentences\n\
288 -w, --width=WIDTH maximum line width (default of 75 columns)\n\
290 fputs (HELP_OPTION_DESCRIPTION
, stdout
);
291 fputs (VERSION_OPTION_DESCRIPTION
, stdout
);
294 With no FILE, or when FILE is -, read standard input.\n"),
296 emit_ancillary_info ();
301 /* Decode options and launch execution. */
303 static struct option
const long_options
[] =
305 {"crown-margin", no_argument
, NULL
, 'c'},
306 {"prefix", required_argument
, NULL
, 'p'},
307 {"split-only", no_argument
, NULL
, 's'},
308 {"tagged-paragraph", no_argument
, NULL
, 't'},
309 {"uniform-spacing", no_argument
, NULL
, 'u'},
310 {"width", required_argument
, NULL
, 'w'},
311 {GETOPT_HELP_OPTION_DECL
},
312 {GETOPT_VERSION_OPTION_DECL
},
317 main (int argc
, char **argv
)
321 char const *max_width_option
= NULL
;
323 initialize_main (&argc
, &argv
);
324 set_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 /* Old option syntax; a dash followed by one or more digits. */
339 max_width_option
= argv
[1] + 1;
341 /* Make the option we just parsed invisible to getopt. */
347 while ((optchar
= getopt_long (argc
, argv
, "0123456789cstuw:p:",
353 if (ISDIGIT (optchar
))
354 error (0, 0, _("invalid option -- %c; -WIDTH is recognized\
355 only when it is the first\noption; use -w N instead"),
357 usage (EXIT_FAILURE
);
376 max_width_option
= optarg
;
383 case_GETOPT_HELP_CHAR
;
385 case_GETOPT_VERSION_CHAR (PROGRAM_NAME
, AUTHORS
);
389 if (max_width_option
)
391 /* Limit max_width to MAXCHARS / 2; otherwise, the resulting
392 output can be quite ugly. */
393 unsigned long int tmp
;
394 if (! (xstrtoul (max_width_option
, NULL
, 10, &tmp
, "") == LONGINT_OK
395 && tmp
<= MAXCHARS
/ 2))
396 error (EXIT_FAILURE
, 0, _("invalid width: %s"),
397 quote (max_width_option
));
401 best_width
= max_width
* (2 * (100 - LEEWAY
) + 1) / 200;
407 for (; optind
< argc
; optind
++)
409 char *file
= argv
[optind
];
410 if (STREQ (file
, "-"))
415 in_stream
= fopen (file
, "r");
416 if (in_stream
!= NULL
)
419 if (fclose (in_stream
) == EOF
)
421 error (0, errno
, "%s", file
);
427 error (0, errno
, _("cannot open %s for reading"),
435 exit (ok
? EXIT_SUCCESS
: EXIT_FAILURE
);
438 /* Trim space from the front and back of the string P, yielding the prefix,
439 and record the lengths of the prefix and the space trimmed. */
446 prefix_lead_space
= 0;
453 prefix_full_length
= strlen (p
);
454 s
= p
+ prefix_full_length
;
455 while (s
> p
&& s
[-1] == ' ')
458 prefix_length
= s
- p
;
461 /* read file F and send formatted output to stdout. */
468 next_char
= get_prefix (f
);
469 while (get_paragraph (f
))
472 put_paragraph (word_limit
);
476 /* Set the global variable `other_indent' according to SAME_PARAGRAPH
477 and other global variables. */
480 set_other_indent (bool same_paragraph
)
483 other_indent
= first_indent
;
486 other_indent
= (same_paragraph
? in_column
: first_indent
);
490 if (same_paragraph
&& in_column
!= first_indent
)
492 other_indent
= in_column
;
495 /* Only one line: use the secondary indent from last time if it
496 splits, or 0 if there have been no multi-line paragraphs in the
497 input so far. But if these rules make the two indents the same,
498 pick a new secondary indent. */
500 else if (other_indent
== first_indent
)
501 other_indent
= first_indent
== 0 ? DEF_INDENT
: 0;
505 other_indent
= first_indent
;
509 /* Read a paragraph from input file F. A paragraph consists of a
510 maximal number of non-blank (excluding any prefix) lines subject to:
511 * In split mode, a paragraph is a single non-blank line.
512 * In crown mode, the second and subsequent lines must have the
513 same indentation, but possibly different from the indent of the
515 * Tagged mode is similar, but the first and second lines must have
516 different indentations.
517 * Otherwise, all lines of a paragraph must have the same indent.
518 If a prefix is in effect, it must be present at the same indent for
519 each line in the paragraph.
521 Return false if end-of-file was encountered before the start of a
522 paragraph, else true. */
525 get_paragraph (FILE *f
)
529 last_line_length
= 0;
532 /* Scan (and copy) blank lines, and lines not introduced by the prefix. */
534 while (c
== '\n' || c
== EOF
535 || next_prefix_indent
< prefix_lead_space
536 || in_column
< next_prefix_indent
+ prefix_full_length
)
538 c
= copy_rest (f
, c
);
548 /* Got a suitable first line for a paragraph. */
550 prefix_indent
= next_prefix_indent
;
551 first_indent
= in_column
;
555 set_other_indent (same_para (c
));
557 /* Read rest of paragraph (unless split is specified). */
568 { /* for each line till the end of the para */
571 while (same_para (c
) && in_column
== other_indent
);
576 if (same_para (c
) && in_column
!= first_indent
)
579 { /* for each line till the end of the para */
582 while (same_para (c
) && in_column
== other_indent
);
587 while (same_para (c
) && in_column
== other_indent
)
590 (word_limit
- 1)->period
= (word_limit
- 1)->final
= true;
595 /* Copy to the output a line that failed to match the prefix, or that
596 was blank after the prefix. In the former case, C is the character
597 that failed to match the prefix. In the latter, C is \n or EOF.
598 Return the character (\n or EOF) ending the line. */
601 copy_rest (FILE *f
, int c
)
606 if (in_column
> next_prefix_indent
|| (c
!= '\n' && c
!= EOF
))
608 put_space (next_prefix_indent
);
609 for (s
= prefix
; out_column
!= in_column
&& *s
; out_column
++)
611 if (c
!= EOF
&& c
!= '\n')
612 put_space (in_column
- out_column
);
613 if (c
== EOF
&& in_column
>= next_prefix_indent
+ prefix_length
)
616 while (c
!= '\n' && c
!= EOF
)
624 /* Return true if a line whose first non-blank character after the
625 prefix (if any) is C could belong to the current paragraph,
631 return (next_prefix_indent
== prefix_indent
632 && in_column
>= next_prefix_indent
+ prefix_full_length
633 && c
!= '\n' && c
!= EOF
);
636 /* Read a line from input file F, given first non-blank character C
637 after the prefix, and the following indent, and break it into words.
638 A word is a maximal non-empty string of non-white characters. A word
639 ending in [.?!]["')\]]* and followed by end-of-line or at least two
640 spaces ends a sentence, as in emacs.
642 Return the first non-blank character of the next line. */
645 get_line (FILE *f
, int c
)
648 char *end_of_parabuf
;
651 end_of_parabuf
= ¶buf
[MAXCHARS
];
652 end_of_word
= &word
[MAXWORDS
- 2];
655 { /* for each word in a line */
659 word_limit
->text
= wptr
;
662 if (wptr
== end_of_parabuf
)
664 set_other_indent (true);
670 while (c
!= EOF
&& !isspace (c
));
671 in_column
+= word_limit
->length
= wptr
- word_limit
->text
;
672 check_punctuation (word_limit
);
674 /* Scan inter-word space. */
677 c
= get_space (f
, c
);
678 word_limit
->space
= in_column
- start
;
679 word_limit
->final
= (c
== EOF
680 || (word_limit
->period
681 && (c
== '\n' || word_limit
->space
> 1)));
682 if (c
== '\n' || c
== EOF
|| uniform
)
683 word_limit
->space
= word_limit
->final
? 2 : 1;
684 if (word_limit
== end_of_word
)
686 set_other_indent (true);
691 while (c
!= '\n' && c
!= EOF
);
692 return get_prefix (f
);
695 /* Read a prefix from input file F. Return either first non-matching
696 character, or first non-blank character after the prefix. */
704 c
= get_space (f
, getc (f
));
705 if (prefix_length
== 0)
706 next_prefix_indent
= prefix_lead_space
< in_column
?
707 prefix_lead_space
: in_column
;
711 next_prefix_indent
= in_column
;
712 for (p
= prefix
; *p
!= '\0'; p
++)
714 unsigned char pc
= *p
;
720 c
= get_space (f
, c
);
725 /* Read blank characters from input file F, starting with C, and keeping
726 in_column up-to-date. Return first non-blank character. */
729 get_space (FILE *f
, int c
)
738 in_column
= (in_column
/ TABWIDTH
+ 1) * TABWIDTH
;
746 /* Set extra fields in word W describing any attached punctuation. */
749 check_punctuation (WORD
*w
)
751 char const *start
= w
->text
;
752 char const *finish
= start
+ (w
->length
- 1);
753 unsigned char fin
= *finish
;
755 w
->paren
= isopen (*start
);
756 w
->punct
= !! ispunct (fin
);
757 while (start
< finish
&& isclose (*finish
))
759 w
->period
= isperiod (*finish
);
762 /* Flush part of the paragraph to make room. This function is called on
763 hitting the limit on the number of words or characters. */
766 flush_paragraph (void)
773 /* In the special case where it's all one word, just flush it. */
775 if (word_limit
== word
)
777 fwrite (parabuf
, sizeof *parabuf
, wptr
- parabuf
, stdout
);
783 - format what you have so far as a paragraph,
784 - find a low-cost line break near the end,
786 - make that the start of the paragraph. */
790 /* Choose a good split point. */
792 split_point
= word_limit
;
793 best_break
= MAXCOST
;
794 for (w
= word
->next_break
; w
!= word_limit
; w
= w
->next_break
)
796 if (w
->best_cost
- w
->next_break
->best_cost
< best_break
)
799 best_break
= w
->best_cost
- w
->next_break
->best_cost
;
801 if (best_break
<= MAXCOST
- LINE_CREDIT
)
802 best_break
+= LINE_CREDIT
;
804 put_paragraph (split_point
);
806 /* Copy text of words down to start of parabuf -- we use memmove because
807 the source and target may overlap. */
809 memmove (parabuf
, split_point
->text
, wptr
- split_point
->text
);
810 shift
= split_point
->text
- parabuf
;
813 /* Adjust text pointers. */
815 for (w
= split_point
; w
<= word_limit
; w
++)
818 /* Copy words from split_point down to word -- we use memmove because
819 the source and target may overlap. */
821 memmove (word
, split_point
, (word_limit
- split_point
+ 1) * sizeof *word
);
822 word_limit
-= split_point
- word
;
825 /* Compute the optimal formatting for the whole paragraph by computing
826 and remembering the optimal formatting for each suffix from the empty
827 one to the whole paragraph. */
837 word_limit
->best_cost
= 0;
838 saved_length
= word_limit
->length
;
839 word_limit
->length
= max_width
; /* sentinel */
841 for (start
= word_limit
- 1; start
>= word
; start
--)
844 len
= start
== word
? first_indent
: other_indent
;
846 /* At least one word, however long, in the line. */
854 /* Consider breaking before w. */
856 wcost
= line_cost (w
, len
) + w
->best_cost
;
857 if (start
== word
&& last_line_length
> 0)
858 wcost
+= RAGGED_COST (len
- last_line_length
);
862 start
->next_break
= w
;
863 start
->line_length
= len
;
866 /* This is a kludge to keep us from computing `len' as the
867 sum of the sentinel length and some non-zero number.
868 Since the sentinel w->length may be INT_MAX, adding
869 to that would give a negative result. */
873 len
+= (w
- 1)->space
+ w
->length
; /* w > start >= word */
875 while (len
< max_width
);
876 start
->best_cost
= best
+ base_cost (start
);
879 word_limit
->length
= saved_length
;
882 /* Return the constant component of the cost of breaking before the
886 base_cost (WORD
*this)
894 if ((this - 1)->period
)
896 if ((this - 1)->final
)
897 cost
-= SENTENCE_BONUS
;
899 cost
+= NOBREAK_COST
;
901 else if ((this - 1)->punct
)
903 else if (this > word
+ 1 && (this - 2)->final
)
904 cost
+= WIDOW_COST ((this - 1)->length
);
909 else if (this->final
)
910 cost
+= ORPHAN_COST (this->length
);
915 /* Return the component of the cost of breaking before word NEXT that
916 depends on LEN, the length of the line beginning there. */
919 line_cost (WORD
*next
, int len
)
924 if (next
== word_limit
)
926 n
= best_width
- len
;
927 cost
= SHORT_COST (n
);
928 if (next
->next_break
!= word_limit
)
930 n
= len
- next
->line_length
;
931 cost
+= RAGGED_COST (n
);
936 /* Output to stdout a paragraph from word up to (but not including)
937 FINISH, which must be in the next_break chain from word. */
940 put_paragraph (WORD
*finish
)
944 put_line (word
, first_indent
);
945 for (w
= word
->next_break
; w
!= finish
; w
= w
->next_break
)
946 put_line (w
, other_indent
);
949 /* Output to stdout the line beginning with word W, beginning in column
950 INDENT, including the prefix (if any). */
953 put_line (WORD
*w
, int indent
)
958 put_space (prefix_indent
);
959 fputs (prefix
, stdout
);
960 out_column
+= prefix_length
;
961 put_space (indent
- out_column
);
963 endline
= w
->next_break
- 1;
964 for (; w
!= endline
; w
++)
967 put_space (w
->space
);
970 last_line_length
= out_column
;
974 /* Output to stdout the word W. */
983 for (n
= w
->length
; n
!= 0; n
--)
985 out_column
+= w
->length
;
988 /* Output to stdout SPACE spaces, or equivalent tabs. */
991 put_space (int space
)
993 int space_target
, tab_target
;
995 space_target
= out_column
+ space
;
998 tab_target
= space_target
/ TABWIDTH
* TABWIDTH
;
999 if (out_column
+ 1 < tab_target
)
1000 while (out_column
< tab_target
)
1003 out_column
= (out_column
/ TABWIDTH
+ 1) * TABWIDTH
;
1006 while (out_column
< space_target
)