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+/* GNU fmt -- simple text formatter.
+ Copyright (C) 1994-2020 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Ross Paterson <rap@doc.ic.ac.uk>. */
+
+#include <config.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <getopt.h>
+#include <assert.h>
+
+/* Redefine. Otherwise, systems (Unicos for one) with headers that define
+ it to be a type get syntax errors for the variable declaration below. */
+#define word unused_word_type
+
+#include "system.h"
+#include "error.h"
+#include "fadvise.h"
+#include "xdectoint.h"
+
+/* The official name of this program (e.g., no 'g' prefix). */
+#define PROGRAM_NAME "fmt"
+
+#define AUTHORS proper_name ("Ross Paterson")
+
+/* The following parameters represent the program's idea of what is
+ "best". Adjust to taste, subject to the caveats given. */
+
+/* Default longest permitted line length (max_width). */
+#define WIDTH 75
+
+/* Prefer lines to be LEEWAY % shorter than the maximum width, giving
+ room for optimization. */
+#define LEEWAY 7
+
+/* The default secondary indent of tagged paragraph used for unindented
+ one-line paragraphs not preceded by any multi-line paragraphs. */
+#define DEF_INDENT 3
+
+/* Costs and bonuses are expressed as the equivalent departure from the
+ optimal line length, multiplied by 10. e.g. assigning something a
+ cost of 50 means that it is as bad as a line 5 characters too short
+ or too long. The definition of SHORT_COST(n) should not be changed.
+ However, EQUIV(n) may need tuning. */
+
+/* FIXME: "fmt" misbehaves given large inputs or options. One
+ possible workaround for part of the problem is to change COST to be
+ a floating-point type. There are other problems besides COST,
+ though; see MAXWORDS below. */
+
+typedef long int COST;
+
+#define MAXCOST TYPE_MAXIMUM (COST)
+
+#define SQR(n) ((n) * (n))
+#define EQUIV(n) SQR ((COST) (n))
+
+/* Cost of a filled line n chars longer or shorter than goal_width. */
+#define SHORT_COST(n) EQUIV ((n) * 10)
+
+/* Cost of the difference between adjacent filled lines. */
+#define RAGGED_COST(n) (SHORT_COST (n) / 2)
+
+/* Basic cost per line. */
+#define LINE_COST EQUIV (70)
+
+/* Cost of breaking a line after the first word of a sentence, where
+ the length of the word is N. */
+#define WIDOW_COST(n) (EQUIV (200) / ((n) + 2))
+
+/* Cost of breaking a line before the last word of a sentence, where
+ the length of the word is N. */
+#define ORPHAN_COST(n) (EQUIV (150) / ((n) + 2))
+
+/* Bonus for breaking a line at the end of a sentence. */
+#define SENTENCE_BONUS EQUIV (50)
+
+/* Cost of breaking a line after a period not marking end of a sentence.
+ With the definition of sentence we are using (borrowed from emacs, see
+ get_line()) such a break would then look like a sentence break. Hence
+ we assign a very high cost -- it should be avoided unless things are
+ really bad. */
+#define NOBREAK_COST EQUIV (600)
+
+/* Bonus for breaking a line before open parenthesis. */
+#define PAREN_BONUS EQUIV (40)
+
+/* Bonus for breaking a line after other punctuation. */
+#define PUNCT_BONUS EQUIV(40)
+
+/* Credit for breaking a long paragraph one line later. */
+#define LINE_CREDIT EQUIV(3)
+
+/* Size of paragraph buffer, in words and characters. Longer paragraphs
+ are handled neatly (cf. flush_paragraph()), so long as these values
+ are considerably greater than required by the width. These values
+ cannot be extended indefinitely: doing so would run into size limits
+ and/or cause more overflows in cost calculations. FIXME: Remove these
+ arbitrary limits. */
+
+#define MAXWORDS 1000
+#define MAXCHARS 5000
+
+/* Extra ctype(3)-style macros. */
+
+#define isopen(c) (strchr ("(['`\"", c) != NULL)
+#define isclose(c) (strchr (")]'\"", c) != NULL)
+#define isperiod(c) (strchr (".?!", c) != NULL)
+
+/* Size of a tab stop, for expansion on input and re-introduction on
+ output. */
+#define TABWIDTH 8
+
+/* Word descriptor structure. */
+
+typedef struct Word WORD;
+
+struct Word
+ {
+
+ /* Static attributes determined during input. */
+
+ const char *text; /* the text of the word */
+ int length; /* length of this word */
+ int space; /* the size of the following space */
+ unsigned int paren:1; /* starts with open paren */
+ unsigned int period:1; /* ends in [.?!])* */
+ unsigned int punct:1; /* ends in punctuation */
+ unsigned int final:1; /* end of sentence */
+
+ /* The remaining fields are computed during the optimization. */
+
+ int line_length; /* length of the best line starting here */
+ COST best_cost; /* cost of best paragraph starting here */
+ WORD *next_break; /* break which achieves best_cost */
+ };
+
+/* Forward declarations. */
+
+static void set_prefix (char *p);
+static void fmt (FILE *f);
+static bool get_paragraph (FILE *f);
+static int get_line (FILE *f, int c);
+static int get_prefix (FILE *f);
+static int get_space (FILE *f, int c);
+static int copy_rest (FILE *f, int c);
+static bool same_para (int c);
+static void flush_paragraph (void);
+static void fmt_paragraph (void);
+static void check_punctuation (WORD *w);
+static COST base_cost (WORD *this);
+static COST line_cost (WORD *next, int len);
+static void put_paragraph (WORD *finish);
+static void put_line (WORD *w, int indent);
+static void put_word (WORD *w);
+static void put_space (int space);
+
+/* Option values. */
+
+/* If true, first 2 lines may have different indent (default false). */
+static bool crown;
+
+/* If true, first 2 lines _must_ have different indent (default false). */
+static bool tagged;
+
+/* If true, each line is a paragraph on its own (default false). */
+static bool split;
+
+/* If true, don't preserve inter-word spacing (default false). */
+static bool uniform;
+
+/* Prefix minus leading and trailing spaces (default ""). */
+static const char *prefix;
+
+/* User-supplied maximum line width (default WIDTH). The only output
+ lines longer than this will each comprise a single word. */
+static int max_width;
+
+/* Values derived from the option values. */
+
+/* The length of prefix minus leading space. */
+static int prefix_full_length;
+
+/* The length of the leading space trimmed from the prefix. */
+static int prefix_lead_space;
+
+/* The length of prefix minus leading and trailing space. */
+static int prefix_length;
+
+/* The preferred width of text lines, set to LEEWAY % less than max_width. */
+static int goal_width;
+
+/* Dynamic variables. */
+
+/* Start column of the character most recently read from the input file. */
+static int in_column;
+
+/* Start column of the next character to be written to stdout. */
+static int out_column;
+
+/* Space for the paragraph text -- longer paragraphs are handled neatly
+ (cf. flush_paragraph()). */
+static char parabuf[MAXCHARS];
+
+/* A pointer into parabuf, indicating the first unused character position. */
+static char *wptr;
+
+/* The words of a paragraph -- longer paragraphs are handled neatly
+ (cf. flush_paragraph()). */
+static WORD word[MAXWORDS];
+
+/* A pointer into the above word array, indicating the first position
+ after the last complete word. Sometimes it will point at an incomplete
+ word. */
+static WORD *word_limit;
+
+/* If true, current input file contains tab characters, and so tabs can be
+ used for white space on output. */
+static bool tabs;
+
+/* Space before trimmed prefix on each line of the current paragraph. */
+static int prefix_indent;
+
+/* Indentation of the first line of the current paragraph. */
+static int first_indent;
+
+/* Indentation of other lines of the current paragraph */
+static int other_indent;
+
+/* To detect the end of a paragraph, we need to look ahead to the first
+ non-blank character after the prefix on the next line, or the first
+ character on the following line that failed to match the prefix.
+ We can reconstruct the lookahead from that character (next_char), its
+ position on the line (in_column) and the amount of space before the
+ prefix (next_prefix_indent). See get_paragraph() and copy_rest(). */
+
+/* The last character read from the input file. */
+static int next_char;
+
+/* The space before the trimmed prefix (or part of it) on the next line
+ after the current paragraph. */
+static int next_prefix_indent;
+
+/* If nonzero, the length of the last line output in the current
+ paragraph, used to charge for raggedness at the split point for long
+ paragraphs chosen by fmt_paragraph(). */
+static int last_line_length;
+
+void
+usage (int status)
+{
+ if (status != EXIT_SUCCESS)
+ emit_try_help ();
+ else
+ {
+ printf (_("Usage: %s [-WIDTH] [OPTION]... [FILE]...\n"), program_name);
+ fputs (_("\
+Reformat each paragraph in the FILE(s), writing to standard output.\n\
+The option -WIDTH is an abbreviated form of --width=DIGITS.\n\
+"), stdout);
+
+ emit_stdin_note ();
+ emit_mandatory_arg_note ();
+
+ fputs (_("\
+ -c, --crown-margin preserve indentation of first two lines\n\
+ -p, --prefix=STRING reformat only lines beginning with STRING,\n\
+ reattaching the prefix to reformatted lines\n\
+ -s, --split-only split long lines, but do not refill\n\
+"),
+ stdout);
+ /* Tell xgettext that the "% o" below is not a printf-style
+ format string: xgettext:no-c-format */
+ fputs (_("\
+ -t, --tagged-paragraph indentation of first line different from second\n\
+ -u, --uniform-spacing one space between words, two after sentences\n\
+ -w, --width=WIDTH maximum line width (default of 75 columns)\n\
+ -g, --goal=WIDTH goal width (default of 93% of width)\n\
+"), stdout);
+ fputs (HELP_OPTION_DESCRIPTION, stdout);
+ fputs (VERSION_OPTION_DESCRIPTION, stdout);
+ emit_ancillary_info (PROGRAM_NAME);
+ }
+ exit (status);
+}
+
+/* Decode options and launch execution. */
+
+static struct option const long_options[] =
+{
+ {"crown-margin", no_argument, NULL, 'c'},
+ {"prefix", required_argument, NULL, 'p'},
+ {"split-only", no_argument, NULL, 's'},
+ {"tagged-paragraph", no_argument, NULL, 't'},
+ {"uniform-spacing", no_argument, NULL, 'u'},
+ {"width", required_argument, NULL, 'w'},
+ {"goal", required_argument, NULL, 'g'},
+ {GETOPT_HELP_OPTION_DECL},
+ {GETOPT_VERSION_OPTION_DECL},
+ {NULL, 0, NULL, 0},
+};
+
+int
+main (int argc, char **argv)
+{
+ int optchar;
+ bool ok = true;
+ char const *max_width_option = NULL;
+ char const *goal_width_option = NULL;
+
+ initialize_main (&argc, &argv);
+ set_program_name (argv[0]);
+ setlocale (LC_ALL, "");
+ bindtextdomain (PACKAGE, LOCALEDIR);
+ textdomain (PACKAGE);
+
+ atexit (close_stdout);
+
+ crown = tagged = split = uniform = false;
+ max_width = WIDTH;
+ prefix = "";
+ prefix_length = prefix_lead_space = prefix_full_length = 0;
+
+ if (argc > 1 && argv[1][0] == '-' && ISDIGIT (argv[1][1]))
+ {
+ /* Old option syntax; a dash followed by one or more digits. */
+ max_width_option = argv[1] + 1;
+
+ /* Make the option we just parsed invisible to getopt. */
+ argv[1] = argv[0];
+ argv++;
+ argc--;
+ }
+
+ while ((optchar = getopt_long (argc, argv, "0123456789cstuw:p:g:",
+ long_options, NULL))
+ != -1)
+ switch (optchar)
+ {
+ default:
+ if (ISDIGIT (optchar))
+ error (0, 0, _("invalid option -- %c; -WIDTH is recognized\
+ only when it is the first\noption; use -w N instead"),
+ optchar);
+ usage (EXIT_FAILURE);
+
+ case 'c':
+ crown = true;
+ break;
+
+ case 's':
+ split = true;
+ break;
+
+ case 't':
+ tagged = true;
+ break;
+
+ case 'u':
+ uniform = true;
+ break;
+
+ case 'w':
+ max_width_option = optarg;
+ break;
+
+ case 'g':
+ goal_width_option = optarg;
+ break;
+
+ case 'p':
+ set_prefix (optarg);
+ break;
+
+ case_GETOPT_HELP_CHAR;
+
+ case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
+
+ }
+
+ if (max_width_option)
+ {
+ /* Limit max_width to MAXCHARS / 2; otherwise, the resulting
+ output can be quite ugly. */
+ max_width = xdectoumax (max_width_option, 0, MAXCHARS / 2, "",
+ _("invalid width"), 0);
+ }
+
+ if (goal_width_option)
+ {
+ /* Limit goal_width to max_width. */
+ goal_width = xdectoumax (goal_width_option, 0, max_width, "",
+ _("invalid width"), 0);
+ if (max_width_option == NULL)
+ max_width = goal_width + 10;
+ }
+ else
+ {
+ goal_width = max_width * (2 * (100 - LEEWAY) + 1) / 200;
+ }
+
+ if (optind == argc)
+ fmt (stdin);
+ else
+ {
+ for (; optind < argc; optind++)
+ {
+ char *file = argv[optind];
+ if (STREQ (file, "-"))
+ fmt (stdin);
+ else
+ {
+ FILE *in_stream;
+ in_stream = fopen (file, "r");
+ if (in_stream != NULL)
+ {
+ fmt (in_stream);
+ if (fclose (in_stream) == EOF)
+ {
+ error (0, errno, "%s", quotef (file));
+ ok = false;
+ }
+ }
+ else
+ {
+ error (0, errno, _("cannot open %s for reading"),
+ quoteaf (file));
+ ok = false;
+ }
+ }
+ }
+ }
+
+ return ok ? EXIT_SUCCESS : EXIT_FAILURE;
+}
+
+/* Trim space from the front and back of the string P, yielding the prefix,
+ and record the lengths of the prefix and the space trimmed. */
+
+static void
+set_prefix (char *p)
+{
+ char *s;
+
+ prefix_lead_space = 0;
+ while (*p == ' ')
+ {
+ prefix_lead_space++;
+ p++;
+ }
+ prefix = p;
+ prefix_full_length = strlen (p);
+ s = p + prefix_full_length;
+ while (s > p && s[-1] == ' ')
+ s--;
+ *s = '\0';
+ prefix_length = s - p;
+}
+
+/* read file F and send formatted output to stdout. */
+
+static void
+fmt (FILE *f)
+{
+ fadvise (f, FADVISE_SEQUENTIAL);
+ tabs = false;
+ other_indent = 0;
+ next_char = get_prefix (f);
+ while (get_paragraph (f))
+ {
+ fmt_paragraph ();
+ put_paragraph (word_limit);
+ }
+}
+
+/* Set the global variable 'other_indent' according to SAME_PARAGRAPH
+ and other global variables. */
+
+static void
+set_other_indent (bool same_paragraph)
+{
+ if (split)
+ other_indent = first_indent;
+ else if (crown)
+ {
+ other_indent = (same_paragraph ? in_column : first_indent);
+ }
+ else if (tagged)
+ {
+ if (same_paragraph && in_column != first_indent)
+ {
+ other_indent = in_column;
+ }
+
+ /* Only one line: use the secondary indent from last time if it
+ splits, or 0 if there have been no multi-line paragraphs in the
+ input so far. But if these rules make the two indents the same,
+ pick a new secondary indent. */
+
+ else if (other_indent == first_indent)
+ other_indent = first_indent == 0 ? DEF_INDENT : 0;
+ }
+ else
+ {
+ other_indent = first_indent;
+ }
+}
+
+/* Read a paragraph from input file F. A paragraph consists of a
+ maximal number of non-blank (excluding any prefix) lines subject to:
+ * In split mode, a paragraph is a single non-blank line.
+ * In crown mode, the second and subsequent lines must have the
+ same indentation, but possibly different from the indent of the
+ first line.
+ * Tagged mode is similar, but the first and second lines must have
+ different indentations.
+ * Otherwise, all lines of a paragraph must have the same indent.
+ If a prefix is in effect, it must be present at the same indent for
+ each line in the paragraph.
+
+ Return false if end-of-file was encountered before the start of a
+ paragraph, else true. */
+
+static bool
+get_paragraph (FILE *f)
+{
+ int c;
+
+ last_line_length = 0;
+ c = next_char;
+
+ /* Scan (and copy) blank lines, and lines not introduced by the prefix. */
+
+ while (c == '\n' || c == EOF
+ || next_prefix_indent < prefix_lead_space
+ || in_column < next_prefix_indent + prefix_full_length)
+ {
+ c = copy_rest (f, c);
+ if (c == EOF)
+ {
+ next_char = EOF;
+ return false;
+ }
+ putchar ('\n');
+ c = get_prefix (f);
+ }
+
+ /* Got a suitable first line for a paragraph. */
+
+ prefix_indent = next_prefix_indent;
+ first_indent = in_column;
+ wptr = parabuf;
+ word_limit = word;
+ c = get_line (f, c);
+ set_other_indent (same_para (c));
+
+ /* Read rest of paragraph (unless split is specified). */
+
+ if (split)
+ {
+ /* empty */
+ }
+ else if (crown)
+ {
+ if (same_para (c))
+ {
+ do
+ { /* for each line till the end of the para */
+ c = get_line (f, c);
+ }
+ while (same_para (c) && in_column == other_indent);
+ }
+ }
+ else if (tagged)
+ {
+ if (same_para (c) && in_column != first_indent)
+ {
+ do
+ { /* for each line till the end of the para */
+ c = get_line (f, c);
+ }
+ while (same_para (c) && in_column == other_indent);
+ }
+ }
+ else
+ {
+ while (same_para (c) && in_column == other_indent)
+ c = get_line (f, c);
+ }
+
+ /* Tell static analysis tools that using word_limit[-1] is ok.
+ word_limit is guaranteed to have been incremented by get_line. */
+ assert (word < word_limit);
+
+ (word_limit - 1)->period = (word_limit - 1)->final = true;
+ next_char = c;
+ return true;
+}
+
+/* Copy to the output a line that failed to match the prefix, or that
+ was blank after the prefix. In the former case, C is the character
+ that failed to match the prefix. In the latter, C is \n or EOF.
+ Return the character (\n or EOF) ending the line. */
+
+static int
+copy_rest (FILE *f, int c)
+{
+ const char *s;
+
+ out_column = 0;
+ if (in_column > next_prefix_indent || (c != '\n' && c != EOF))
+ {
+ put_space (next_prefix_indent);
+ for (s = prefix; out_column != in_column && *s; out_column++)
+ putchar (*s++);
+ if (c != EOF && c != '\n')
+ put_space (in_column - out_column);
+ if (c == EOF && in_column >= next_prefix_indent + prefix_length)
+ putchar ('\n');
+ }
+ while (c != '\n' && c != EOF)
+ {
+ putchar (c);
+ c = getc (f);
+ }
+ return c;
+}
+
+/* Return true if a line whose first non-blank character after the
+ prefix (if any) is C could belong to the current paragraph,
+ otherwise false. */
+
+static bool
+same_para (int c)
+{
+ return (next_prefix_indent == prefix_indent
+ && in_column >= next_prefix_indent + prefix_full_length
+ && c != '\n' && c != EOF);
+}
+
+/* Read a line from input file F, given first non-blank character C
+ after the prefix, and the following indent, and break it into words.
+ A word is a maximal non-empty string of non-white characters. A word
+ ending in [.?!]["')\]]* and followed by end-of-line or at least two
+ spaces ends a sentence, as in emacs.
+
+ Return the first non-blank character of the next line. */
+
+static int
+get_line (FILE *f, int c)
+{
+ int start;
+ char *end_of_parabuf;
+ WORD *end_of_word;
+
+ end_of_parabuf = &parabuf[MAXCHARS];
+ end_of_word = &word[MAXWORDS - 2];
+
+ do
+ { /* for each word in a line */
+
+ /* Scan word. */
+
+ word_limit->text = wptr;
+ do
+ {
+ if (wptr == end_of_parabuf)
+ {
+ set_other_indent (true);
+ flush_paragraph ();
+ }
+ *wptr++ = c;
+ c = getc (f);
+ }
+ while (c != EOF && !isspace (c));
+ in_column += word_limit->length = wptr - word_limit->text;
+ check_punctuation (word_limit);
+
+ /* Scan inter-word space. */
+
+ start = in_column;
+ c = get_space (f, c);
+ word_limit->space = in_column - start;
+ word_limit->final = (c == EOF
+ || (word_limit->period
+ && (c == '\n' || word_limit->space > 1)));
+ if (c == '\n' || c == EOF || uniform)
+ word_limit->space = word_limit->final ? 2 : 1;
+ if (word_limit == end_of_word)
+ {
+ set_other_indent (true);
+ flush_paragraph ();
+ }
+ word_limit++;
+ }
+ while (c != '\n' && c != EOF);
+ return get_prefix (f);
+}
+
+/* Read a prefix from input file F. Return either first non-matching
+ character, or first non-blank character after the prefix. */
+
+static int
+get_prefix (FILE *f)
+{
+ int c;
+
+ in_column = 0;
+ c = get_space (f, getc (f));
+ if (prefix_length == 0)
+ next_prefix_indent = prefix_lead_space < in_column ?
+ prefix_lead_space : in_column;
+ else
+ {
+ const char *p;
+ next_prefix_indent = in_column;
+ for (p = prefix; *p != '\0'; p++)
+ {
+ unsigned char pc = *p;
+ if (c != pc)
+ return c;
+ in_column++;
+ c = getc (f);
+ }
+ c = get_space (f, c);
+ }
+ return c;
+}
+
+/* Read blank characters from input file F, starting with C, and keeping
+ in_column up-to-date. Return first non-blank character. */
+
+static int
+get_space (FILE *f, int c)
+{
+ while (true)
+ {
+ if (c == ' ')
+ in_column++;
+ else if (c == '\t')
+ {
+ tabs = true;
+ in_column = (in_column / TABWIDTH + 1) * TABWIDTH;
+ }
+ else
+ return c;
+ c = getc (f);
+ }
+}
+
+/* Set extra fields in word W describing any attached punctuation. */
+
+static void
+check_punctuation (WORD *w)
+{
+ char const *start = w->text;
+ char const *finish = start + (w->length - 1);
+ unsigned char fin = *finish;
+
+ w->paren = isopen (*start);
+ w->punct = !! ispunct (fin);
+ while (start < finish && isclose (*finish))
+ finish--;
+ w->period = isperiod (*finish);
+}
+
+/* Flush part of the paragraph to make room. This function is called on
+ hitting the limit on the number of words or characters. */
+
+static void
+flush_paragraph (void)
+{
+ WORD *split_point;
+ WORD *w;
+ int shift;
+ COST best_break;
+
+ /* In the special case where it's all one word, just flush it. */
+
+ if (word_limit == word)
+ {
+ fwrite (parabuf, sizeof *parabuf, wptr - parabuf, stdout);
+ wptr = parabuf;
+ return;
+ }
+
+ /* Otherwise:
+ - format what you have so far as a paragraph,
+ - find a low-cost line break near the end,
+ - output to there,
+ - make that the start of the paragraph. */
+
+ fmt_paragraph ();
+
+ /* Choose a good split point. */
+
+ split_point = word_limit;
+ best_break = MAXCOST;
+ for (w = word->next_break; w != word_limit; w = w->next_break)
+ {
+ if (w->best_cost - w->next_break->best_cost < best_break)
+ {
+ split_point = w;
+ best_break = w->best_cost - w->next_break->best_cost;
+ }
+ if (best_break <= MAXCOST - LINE_CREDIT)
+ best_break += LINE_CREDIT;
+ }
+ put_paragraph (split_point);
+
+ /* Copy text of words down to start of parabuf -- we use memmove because
+ the source and target may overlap. */
+
+ memmove (parabuf, split_point->text, wptr - split_point->text);
+ shift = split_point->text - parabuf;
+ wptr -= shift;
+
+ /* Adjust text pointers. */
+
+ for (w = split_point; w <= word_limit; w++)
+ w->text -= shift;
+
+ /* Copy words from split_point down to word -- we use memmove because
+ the source and target may overlap. */
+
+ memmove (word, split_point, (word_limit - split_point + 1) * sizeof *word);
+ word_limit -= split_point - word;
+}
+
+/* Compute the optimal formatting for the whole paragraph by computing
+ and remembering the optimal formatting for each suffix from the empty
+ one to the whole paragraph. */
+
+static void
+fmt_paragraph (void)
+{
+ WORD *start, *w;
+ int len;
+ COST wcost, best;
+ int saved_length;
+
+ word_limit->best_cost = 0;
+ saved_length = word_limit->length;
+ word_limit->length = max_width; /* sentinel */
+
+ for (start = word_limit - 1; start >= word; start--)
+ {
+ best = MAXCOST;
+ len = start == word ? first_indent : other_indent;
+
+ /* At least one word, however long, in the line. */
+
+ w = start;
+ len += w->length;
+ do
+ {
+ w++;
+
+ /* Consider breaking before w. */
+
+ wcost = line_cost (w, len) + w->best_cost;
+ if (start == word && last_line_length > 0)
+ wcost += RAGGED_COST (len - last_line_length);
+ if (wcost < best)
+ {
+ best = wcost;
+ start->next_break = w;
+ start->line_length = len;
+ }
+
+ /* This is a kludge to keep us from computing 'len' as the
+ sum of the sentinel length and some non-zero number.
+ Since the sentinel w->length may be INT_MAX, adding
+ to that would give a negative result. */
+ if (w == word_limit)
+ break;
+
+ len += (w - 1)->space + w->length; /* w > start >= word */
+ }
+ while (len < max_width);
+ start->best_cost = best + base_cost (start);
+ }
+
+ word_limit->length = saved_length;
+}
+
+/* Return the constant component of the cost of breaking before the
+ word THIS. */
+
+static COST
+base_cost (WORD *this)
+{
+ COST cost;
+
+ cost = LINE_COST;
+
+ if (this > word)
+ {
+ if ((this - 1)->period)
+ {
+ if ((this - 1)->final)
+ cost -= SENTENCE_BONUS;
+ else
+ cost += NOBREAK_COST;
+ }
+ else if ((this - 1)->punct)
+ cost -= PUNCT_BONUS;
+ else if (this > word + 1 && (this - 2)->final)
+ cost += WIDOW_COST ((this - 1)->length);
+ }
+
+ if (this->paren)
+ cost -= PAREN_BONUS;
+ else if (this->final)
+ cost += ORPHAN_COST (this->length);
+
+ return cost;
+}
+
+/* Return the component of the cost of breaking before word NEXT that
+ depends on LEN, the length of the line beginning there. */
+
+static COST
+line_cost (WORD *next, int len)
+{
+ int n;
+ COST cost;
+
+ if (next == word_limit)
+ return 0;
+ n = goal_width - len;
+ cost = SHORT_COST (n);
+ if (next->next_break != word_limit)
+ {
+ n = len - next->line_length;
+ cost += RAGGED_COST (n);
+ }
+ return cost;
+}
+
+/* Output to stdout a paragraph from word up to (but not including)
+ FINISH, which must be in the next_break chain from word. */
+
+static void
+put_paragraph (WORD *finish)
+{
+ WORD *w;
+
+ put_line (word, first_indent);
+ for (w = word->next_break; w != finish; w = w->next_break)
+ put_line (w, other_indent);
+}
+
+/* Output to stdout the line beginning with word W, beginning in column
+ INDENT, including the prefix (if any). */
+
+static void
+put_line (WORD *w, int indent)
+{
+ WORD *endline;
+
+ out_column = 0;
+ put_space (prefix_indent);
+ fputs (prefix, stdout);
+ out_column += prefix_length;
+ put_space (indent - out_column);
+
+ endline = w->next_break - 1;
+ for (; w != endline; w++)
+ {
+ put_word (w);
+ put_space (w->space);
+ }
+ put_word (w);
+ last_line_length = out_column;
+ putchar ('\n');
+}
+
+/* Output to stdout the word W. */
+
+static void
+put_word (WORD *w)
+{
+ const char *s;
+ int n;
+
+ s = w->text;
+ for (n = w->length; n != 0; n--)
+ putchar (*s++);
+ out_column += w->length;
+}
+
+/* Output to stdout SPACE spaces, or equivalent tabs. */
+
+static void
+put_space (int space)
+{
+ int space_target, tab_target;
+
+ space_target = out_column + space;
+ if (tabs)
+ {
+ tab_target = space_target / TABWIDTH * TABWIDTH;
+ if (out_column + 1 < tab_target)
+ while (out_column < tab_target)
+ {
+ putchar ('\t');
+ out_column = (out_column / TABWIDTH + 1) * TABWIDTH;
+ }
+ }
+ while (out_column < space_target)
+ {
+ putchar (' ');
+ out_column++;
+ }
+}