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., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307, USA.
  19  */
  20
  21 #include <config.h>
  22 #include "edit.h"
  23
  24 #define tab_width option_tab_spacing
  25
  26 int line_is_blank (WEdit * edit, long line);
  27
  28 #define NO_FORMAT_CHARS_START "-+*\\,.;:&>"
  29
  30 static long
  31 line_start (WEdit *edit, long line)
  32 {
  33     long p, l;
  34
  35     l = edit->curs_line;
  36     p = edit->curs1;
  37
  38     if (line < l)
  39         p = edit_move_backward (edit, p, l - line);
  40     else if (line > l)
  41         p = edit_move_forward (edit, p, line - l, 0);
  42
  43     p = edit_bol (edit, p);
  44     while (strchr ("\t ", edit_get_byte (edit, p)))
  45         p++;
  46     return p;
  47 }
  48
  49 static int bad_line_start (WEdit * edit, long p)
  50 {
  51     int c;
  52     c = edit_get_byte (edit, p);
  53     if (c == '.') {             /* `...' is acceptable */
  54         if (edit_get_byte (edit, p + 1) == '.')
  55             if (edit_get_byte (edit, p + 2) == '.')
  56                 return 0;
  57         return 1;
  58     }
  59     if (c == '-') {
  60         if (edit_get_byte (edit, p + 1) == '-')
  61             if (edit_get_byte (edit, p + 2) == '-')
  62                 return 0;       /* `---' is acceptable */
  63         return 1;
  64     }
  65     if (strchr (NO_FORMAT_CHARS_START, c))
  66         return 1;
  67     return 0;
  68 }
  69
  70 /*
  71  * Find the start of the current paragraph for the purpose of formatting.
  72  * Return position in the file.
  73  */
  74 static long
  75 begin_paragraph (WEdit *edit, int force)
  76 {
  77     int i;
  78     for (i = edit->curs_line - 1; i >= 0; i--) {
  79         if (line_is_blank (edit, i)) {
  80             i++;
  81             break;
  82         }
  83         if (force) {
  84             if (bad_line_start (edit, line_start (edit, i))) {
  85                 i++;
  86                 break;
  87             }
  88         }
  89     }
  90     return edit_move_backward (edit, edit_bol (edit, edit->curs1),
  91                                edit->curs_line - i);
  92 }
  93
  94 /*
  95  * Find the end of the current paragraph for the purpose of formatting.
  96  * Return position in the file.
  97  */
  98 static long
  99 end_paragraph (WEdit *edit, int force)
 100 {
 101     int i;
 102     for (i = edit->curs_line + 1; i <= edit->total_lines; i++) {
 103         if (line_is_blank (edit, i)) {
 104             i--;
 105             break;
 106         }
 107         if (force)
 108             if (bad_line_start (edit, line_start (edit, i))) {
 109                 i--;
 110                 break;
 111             }
 112     }
 113     return edit_eol (edit,
 114                      edit_move_forward (edit, edit_bol (edit, edit->curs1),
 115                                         i - edit->curs_line, 0));
 116 }
 117
 118 static unsigned char *get_paragraph (WEdit * edit, long p, long q, int indent, int *size)
 119 {
 120     unsigned char *s, *t;
 121 #if 0
 122     t = malloc ((q - p) + 2 * (q - p) / option_word_wrap_line_length + 10);
 123 #else
 124     t = malloc (2 * (q - p) + 100);
 125 #endif
 126     if (!t)
 127         return 0;
 128     for (s = t; p < q; p++, s++) {
 129         if (indent)
 130             if (edit_get_byte (edit, p - 1) == '\n')
 131                 while (strchr ("\t ", edit_get_byte (edit, p)))
 132                     p++;
 133         *s = edit_get_byte (edit, p);
 134     }
 135     *size = (unsigned long) s - (unsigned long) t;
 136     t[*size] = '\n';
 137     return t;
 138 }
 139
 140 static void strip_newlines (unsigned char *t, int size)
 141 {
 142     unsigned char *p = t;
 143     while (size--) {
 144         *p = *p == '\n' ? ' ' : *p;
 145         p++;
 146     }
 147 }
 148
 149 /*
 150    This is a copy of the function
 151    int calc_text_pos (WEdit * edit, long b, long *q, int l)
 152    in propfont.c  :(
 153    It calculates the number of chars in a line specified to length l in pixels
 154  */
 155 static inline int next_tab_pos (int x)
 156 {
 157     return x += tab_width - x % tab_width;
 158 }
 159 static int line_pixel_length (unsigned char *t, long b, int l)
 160 {
 161     int x = 0, c, xn = 0;
 162     for (;;) {
 163         c = t[b];
 164         switch (c) {
 165         case '\n':
 166             return b;
 167         case '\t':
 168             xn = next_tab_pos (x);
 169             break;
 170         default:
 171             xn = x + 1;
 172             break;
 173         }
 174         if (xn > l)
 175             break;
 176         x = xn;
 177         b++;
 178     }
 179     return b;
 180 }
 181
 182 /* find the start of a word */
 183 static int next_word_start (unsigned char *t, int q, int size)
 184 {
 185     int i;
 186     for (i = q;; i++) {
 187         switch (t[i]) {
 188         case '\n':
 189             return -1;
 190         case '\t':
 191         case ' ':
 192             for (;; i++) {
 193                 if (t[i] == '\n')
 194                     return -1;
 195                 if (t[i] != ' ' && t[i] != '\t')
 196                     return i;
 197             }
 198             break;
 199         }
 200     }
 201 }
 202
 203 /* find the start of a word */
 204 static int word_start (unsigned char *t, int q, int size)
 205 {
 206     int i = q;
 207     if (t[q] == ' ' || t[q] == '\t')
 208         return next_word_start (t, q, size);
 209     for (;;) {
 210         int c;
 211         if (!i)
 212             return -1;
 213         c = t[i - 1];
 214         if (c == '\n')
 215             return -1;
 216         if (c == ' ' || c == '\t')
 217             return i;
 218         i--;
 219     }
 220 }
 221
 222 /* replaces ' ' with '\n' to properly format a paragraph */
 223 static void format_this (unsigned char *t, int size, int indent)
 224 {
 225     int q = 0, ww;
 226     strip_newlines (t, size);
 227     ww = option_word_wrap_line_length * FONT_MEAN_WIDTH - indent;
 228     if (ww < FONT_MEAN_WIDTH * 2)
 229         ww = FONT_MEAN_WIDTH * 2;
 230     for (;;) {
 231         int p;
 232         q = line_pixel_length (t, q, ww);
 233         if (q > size)
 234             break;
 235         if (t[q] == '\n')
 236             break;
 237         p = word_start (t, q, size);
 238         if (p == -1)
 239             q = next_word_start (t, q, size);   /* Return the end of the word if the beginning
 240                                                    of the word is at the beginning of a line
 241                                                    (i.e. a very long word) */
 242         else
 243             q = p;
 244         if (q == -1)    /* end of paragraph */
 245             break;
 246         if (q)
 247             t[q - 1] = '\n';
 248     }
 249 }
 250
 251 static void replace_at (WEdit * edit, long q, int c)
 252 {
 253     edit_cursor_move (edit, q - edit->curs1);
 254     edit_delete (edit);
 255     edit_insert_ahead (edit, c);
 256 }
 257
 258 void edit_insert_indent (WEdit * edit, int indent);
 259
 260 /* replaces a block of text */
 261 static void put_paragraph (WEdit * edit, unsigned char *t, long p, long q, int indent, int size)
 262 {
 263     long cursor;
 264     int i, c = 0;
 265     cursor = edit->curs1;
 266     if (indent)
 267         while (strchr ("\t ", edit_get_byte (edit, p)))
 268             p++;
 269     for (i = 0; i < size; i++, p++) {
 270         if (i && indent) {
 271             if (t[i - 1] == '\n' && c == '\n') {
 272                 while (strchr ("\t ", edit_get_byte (edit, p)))
 273                     p++;
 274             } else if (t[i - 1] == '\n') {
 275                 long curs;
 276                 edit_cursor_move (edit, p - edit->curs1);
 277                 curs = edit->curs1;
 278                 edit_insert_indent (edit, indent);
 279                 if (cursor >= curs)
 280                     cursor += edit->curs1 - p;
 281                 p = edit->curs1;
 282             } else if (c == '\n') {
 283                 edit_cursor_move (edit, p - edit->curs1);
 284                 while (strchr ("\t ", edit_get_byte (edit, p))) {
 285                     edit_delete (edit);
 286                     if (cursor > edit->curs1)
 287                         cursor--;
 288                 }
 289                 p = edit->curs1;
 290             }
 291         }
 292         c = edit_get_byte (edit, p);
 293         if (c != t[i])
 294             replace_at (edit, p, t[i]);
 295     }
 296     edit_cursor_move (edit, cursor - edit->curs1);      /* restore cursor position */
 297 }
 298
 299 int edit_indent_width (WEdit * edit, long p);
 300
 301 static int test_indent (WEdit * edit, long p, long q)
 302 {
 303     int indent;
 304     indent = edit_indent_width (edit, p++);
 305     if (!indent)
 306         return 0;
 307     for (; p < q; p++)
 308         if (edit_get_byte (edit, p - 1) == '\n')
 309             if (indent != edit_indent_width (edit, p))
 310                 return 0;
 311     return indent;
 312 }
 313
 314 void format_paragraph (WEdit * edit, int force)
 315 {
 316     long p, q;
 317     int size;
 318     unsigned char *t;
 319     int indent = 0;
 320     if (option_word_wrap_line_length < 2)
 321         return;
 322     if (line_is_blank (edit, edit->curs_line))
 323         return;
 324     p = begin_paragraph (edit, force);
 325     q = end_paragraph (edit, force);
 326     indent = test_indent (edit, p, q);
 327     t = get_paragraph (edit, p, q, indent, &size);
 328     if (!t)
 329         return;
 330     if (!force) {
 331         int i;
 332         if (strchr (NO_FORMAT_CHARS_START, *t)) {
 333             free (t);
 334             return;
 335         }
 336         for (i = 0; i < size - 1; i++) {
 337             if (t[i] == '\n') {
 338                 if (strchr (NO_FORMAT_CHARS_START "\t ", t[i + 1])) {
 339                     free (t);
 340                     return;
 341                 }
 342             }
 343         }
 344     }
 345     format_this (t, q - p, indent);
 346     put_paragraph (edit, t, p, q, indent, size);
 347     free (t);
 348
 349     /* Scroll left as much as possible to show the formatted paragraph */
 350     edit_scroll_left(edit, - edit->start_col);
 351 }