rosapps/mc/edit/wordproc.c

   1 /* wordproc.c - word-processor mode for the editor: does dynamic
   2                 paragraph formatting.
   3    Copyright (C) 1996 Paul Sheer
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software
  17    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19
  20 #include <config.h>
  21 #include "edit.h"
  22
  23 #ifdef MIDNIGHT
  24 #define tab_width option_tab_spacing
  25 #endif
  26
  27 int line_is_blank (WEdit * edit, long line);
  28
  29 #define NO_FORMAT_CHARS_START "-+*\\,.;:&>"
  30
  31 static long line_start (WEdit * edit, long line)
  32 {
  33     static long p = -1, l = 0;
  34     int c;
  35     if (p == -1 || abs (l - line) > abs (edit->curs_line - line)) {
  36         l = edit->curs_line;
  37         p = edit->curs1;
  38     }
  39     if (line < l)
  40         p = edit_move_backward (edit, p, l - line);
  41     else if (line > l)
  42         p = edit_move_forward (edit, p, line - l, 0);
  43     l = line;
  44     p = edit_bol (edit, p);
  45     while (strchr ("\t ", c = edit_get_byte (edit, p)))
  46         p++;
  47     return p;
  48 }
  49
  50 static int bad_line_start (WEdit * edit, long p)
  51 {
  52     int c;
  53     c = edit_get_byte (edit, p);
  54     if (c == '.') {             /* `...' is acceptable */
  55         if (edit_get_byte (edit, p + 1) == '.')
  56             if (edit_get_byte (edit, p + 2) == '.')
  57                 return 0;
  58         return 1;
  59     }
  60     if (c == '-') {
  61         if (edit_get_byte (edit, p + 1) == '-')
  62             if (edit_get_byte (edit, p + 2) == '-')
  63                 return 0;       /* `---' is acceptable */
  64         return 1;
  65     }
  66     if (strchr (NO_FORMAT_CHARS_START, c))
  67         return 1;
  68     return 0;
  69 }
  70
  71 static long begin_paragraph (WEdit * edit, long p, int force)
  72 {
  73     int i;
  74     for (i = edit->curs_line - 1; i > 0; i--) {
  75         if (line_is_blank (edit, i)) {
  76             i++;
  77             break;
  78         }
  79         if (force) {
  80             if (bad_line_start (edit, line_start (edit, i))) {
  81                 i++;
  82                 break;
  83             }
  84         }
  85     }
  86     return edit_move_backward (edit, edit_bol (edit, edit->curs1), edit->curs_line - i);
  87 }
  88
  89 static long end_paragraph (WEdit * edit, long p, int force)
  90 {
  91     int i;
  92     for (i = edit->curs_line + 1; i < edit->total_lines; i++) {
  93         if (line_is_blank (edit, i)) {
  94             i--;
  95             break;
  96         }
  97         if (force)
  98             if (bad_line_start (edit, line_start (edit, i))) {
  99                 i--;
 100                 break;
 101             }
 102     }
 103     return edit_eol (edit, edit_move_forward (edit, edit_bol (edit, edit->curs1), i - edit->curs_line, 0));
 104 }
 105
 106 static char *get_paragraph (WEdit * edit, long p, long q, int indent, int *size)
 107 {
 108     char *s, *t;
 109     t = malloc ((q - p) + 2 * (q - p) / option_word_wrap_line_length + 10);
 110     if (!t)
 111         return 0;
 112     for (s = t; p < q; p++, s++) {
 113         if (indent)
 114             if (edit_get_byte (edit, p - 1) == '\n')
 115                 while (strchr ("\t ", edit_get_byte (edit, p)))
 116                     p++;
 117         *s = edit_get_byte (edit, p);
 118     }
 119     *size = (unsigned long) s - (unsigned long) t;
 120     t[*size] = '\n';
 121     return t;
 122 }
 123
 124 static void strip_newlines (char *t, int size)
 125 {
 126     char *p = t;
 127     while (size--) {
 128         *p = *p == '\n' ? ' ' : *p;
 129         p++;
 130     }
 131 }
 132
 133 #ifndef MIDNIGHT
 134 int edit_width_of_long_printable (int c);
 135 #endif
 136 /*
 137    This is a copy of the function
 138    int calc_text_pos (WEdit * edit, long b, long *q, int l)
 139    in propfont.c  :(
 140    It calculates the number of chars in a line specified to length l in pixels
 141  */
 142 extern int tab_width;
 143 static inline int next_tab_pos (int x)
 144 {
 145     return x += tab_width - x % tab_width;
 146 }
 147 static int line_pixel_length (char *t, long b, int l)
 148 {
 149     int x = 0, c, xn = 0;
 150     for (;;) {
 151         c = t[b];
 152         switch (c) {
 153         case '\n':
 154             return b;
 155         case '\t':
 156             xn = next_tab_pos (x);
 157             break;
 158         default:
 159 #ifdef MIDNIGHT
 160             xn = x + 1;
 161 #else
 162             xn = x + edit_width_of_long_printable (c);
 163 #endif
 164             break;
 165         }
 166         if (xn > l)
 167             break;
 168         x = xn;
 169         b++;
 170     }
 171     return b;
 172 }
 173
 174 /* find the start of a word */
 175 static int next_word_start (char *t, int q, int size)
 176 {
 177     int i;
 178     for (i = q;; i++) {
 179         switch (t[i]) {
 180         case '\n':
 181             return -1;
 182         case '\t':
 183         case ' ':
 184             for (;; i++) {
 185                 if (t[i] == '\n')
 186                     return -1;
 187                 if (t[i] != ' ' && t[i] != '\t')
 188                     return i;
 189             }
 190             break;
 191         }
 192     }
 193 }
 194
 195 /* find the start of a word */
 196 static int word_start (char *t, int q, int size)
 197 {
 198     int i = q;
 199     if (t[q] == ' ' || t[q] == '\t')
 200         return next_word_start (t, q, size);
 201     for (;;) {
 202         int c;
 203         if (!i)
 204             return -1;
 205         c = t[i - 1];
 206         if (c == '\n')
 207             return -1;
 208         if (c == ' ' || c == '\t')
 209             return i;
 210         i--;
 211     }
 212 }
 213
 214 /* replaces ' ' with '\n' to properly format a paragraph */
 215 static void format_this (char *t, int size, int indent)
 216 {
 217     int q = 0, ww;
 218     strip_newlines (t, size);
 219     ww = option_word_wrap_line_length * FONT_MEAN_WIDTH - indent;
 220     if (ww < FONT_MEAN_WIDTH * 2)
 221         ww = FONT_MEAN_WIDTH * 2;
 222     for (;;) {
 223         int p;
 224         q = line_pixel_length (t, q, ww);
 225         if (q > size)
 226             break;
 227         if (t[q] == '\n')
 228             break;
 229         p = word_start (t, q, size);
 230         if (p == -1)
 231             q = next_word_start (t, q, size);   /* Return the end of the word if the beginning
 232                                                    of the word is at the beginning of a line
 233                                                    (i.e. a very long word) */
 234         else
 235             q = p;
 236         if (q == -1)    /* end of paragraph */
 237             break;
 238         if (q)
 239             t[q - 1] = '\n';
 240     }
 241 }
 242
 243 static void replace_at (WEdit * edit, long q, int c)
 244 {
 245     edit_cursor_move (edit, q - edit->curs1);
 246     edit_delete (edit);
 247     edit_insert_ahead (edit, c);
 248 }
 249
 250 void edit_insert_indent (WEdit * edit, int indent);
 251
 252 /* replaces a block of text */
 253 static void put_paragraph (WEdit * edit, char *t, long p, long q, int indent, int size)
 254 {
 255     long cursor;
 256     int i, c = 0;
 257     cursor = edit->curs1;
 258     if (indent)
 259         while (strchr ("\t ", edit_get_byte (edit, p)))
 260             p++;
 261     for (i = 0; i < size; i++, p++) {
 262         if (i && indent) {
 263             if (t[i - 1] == '\n' && c == '\n') {
 264                 while (strchr ("\t ", edit_get_byte (edit, p)))
 265                     p++;
 266             } else if (t[i - 1] == '\n') {
 267                 long curs;
 268                 edit_cursor_move (edit, p - edit->curs1);
 269                 curs = edit->curs1;
 270                 edit_insert_indent (edit, indent);
 271                 if (cursor >= curs)
 272                     cursor += edit->curs1 - p;
 273                 p = edit->curs1;
 274             } else if (c == '\n') {
 275                 edit_cursor_move (edit, p - edit->curs1);
 276                 while (strchr ("\t ", edit_get_byte (edit, p))) {
 277                     edit_delete (edit);
 278                     if (cursor > edit->curs1)
 279                         cursor--;
 280                 }
 281                 p = edit->curs1;
 282             }
 283         }
 284         c = edit_get_byte (edit, p);
 285         if (c != t[i])
 286             replace_at (edit, p, t[i]);
 287     }
 288     edit_cursor_move (edit, cursor - edit->curs1);      /* restore cursor position */
 289 }
 290
 291 int edit_indent_width (WEdit * edit, long p);
 292
 293 static int test_indent (WEdit * edit, long p, long q)
 294 {
 295     int indent;
 296     indent = edit_indent_width (edit, p++);
 297     if (!indent)
 298         return 0;
 299     for (; p < q; p++)
 300         if (edit_get_byte (edit, p - 1) == '\n')
 301             if (indent != edit_indent_width (edit, p))
 302                 return 0;
 303     return indent;
 304 }
 305
 306 void format_paragraph (WEdit * edit, int force)
 307 {
 308     long p, q;
 309     int size;
 310     char *t;
 311     int indent = 0;
 312     if (option_word_wrap_line_length < 2)
 313         return;
 314     if (line_is_blank (edit, edit->curs_line))
 315         return;
 316     p = begin_paragraph (edit, edit->curs1, force);
 317     q = end_paragraph (edit, edit->curs1, force);
 318     indent = test_indent (edit, p, q);
 319     t = get_paragraph (edit, p, q, indent, &size);
 320     if (!t)
 321         return;
 322     if (!force) {
 323         int i;
 324         if (strchr (NO_FORMAT_CHARS_START, *t)) {
 325             free (t);
 326             return;
 327         }
 328         for (i = 0; i < size - 1; i++) {
 329             if (t[i] == '\n') {
 330                 if (strchr (NO_FORMAT_CHARS_START "\t ", t[i + 1])) {
 331                     free (t);
 332                     return;
 333                 }
 334             }
 335         }
 336     }
 337     format_this (t, q - p, indent);
 338     put_paragraph (edit, t, p, q, indent, size);
 339     free (t);
 340 }
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