src/editor/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., 51 Franklin Street, Fifth Floor, Boston, MA
  18    02110-1301, USA.
  19  */
  20
  21 /** \file
  22  *  \brief Source: word-processor mode for the editor: does dynamic paragraph formatting
  23  *  \author Paul Sheer
  24  *  \date 1996
  25  */
  26
  27 #include <config.h>
  28
  29 #include <stdio.h>
  30 #include <stdarg.h>
  31 #include <sys/types.h>
  32 #include <unistd.h>
  33 #include <string.h>
  34 #include <ctype.h>
  35 #include <errno.h>
  36 #include <sys/stat.h>
  37
  38 #include <stdlib.h>
  39
  40 #include "lib/global.h"
  41
  42 #include "src/setup.h"          /* option_tab_spacing */
  43
  44 #include "edit-impl.h"
  45 #include "edit-widget.h"
  46
  47 /*** global variables ****************************************************************************/
  48
  49 /*** file scope macro definitions ****************************************************************/
  50
  51 #define tab_width option_tab_spacing
  52
  53 #define NO_FORMAT_CHARS_START "-+*\\,.;:&>"
  54 #define FONT_MEAN_WIDTH 1
  55
  56 /*** file scope type declarations ****************************************************************/
  57
  58 /*** file scope variables ************************************************************************/
  59
  60 /*** file scope functions ************************************************************************/
  61 /* --------------------------------------------------------------------------------------------- */
  62
  63 static long
  64 line_start (WEdit * edit, long line)
  65 {
  66     long p, l;
  67
  68     l = edit->curs_line;
  69     p = edit->curs1;
  70
  71     if (line < l)
  72         p = edit_move_backward (edit, p, l - line);
  73     else if (line > l)
  74         p = edit_move_forward (edit, p, line - l, 0);
  75
  76     p = edit_bol (edit, p);
  77     while (strchr ("\t ", edit_get_byte (edit, p)))
  78         p++;
  79     return p;
  80 }
  81
  82 /* --------------------------------------------------------------------------------------------- */
  83
  84 static int
  85 bad_line_start (WEdit * edit, long p)
  86 {
  87     int c;
  88     c = edit_get_byte (edit, p);
  89     if (c == '.')
  90     {                           /* `...' is acceptable */
  91         if (edit_get_byte (edit, p + 1) == '.')
  92             if (edit_get_byte (edit, p + 2) == '.')
  93                 return 0;
  94         return 1;
  95     }
  96     if (c == '-')
  97     {
  98         if (edit_get_byte (edit, p + 1) == '-')
  99             if (edit_get_byte (edit, p + 2) == '-')
 100                 return 0;       /* `---' is acceptable */
 101         return 1;
 102     }
 103     if (strchr (NO_FORMAT_CHARS_START, c))
 104         return 1;
 105     return 0;
 106 }
 107
 108 /* --------------------------------------------------------------------------------------------- */
 109 /**
 110  * Find the start of the current paragraph for the purpose of formatting.
 111  * Return position in the file.
 112  */
 113
 114 static long
 115 begin_paragraph (WEdit * edit, int force)
 116 {
 117     long i;
 118     for (i = edit->curs_line - 1; i >= 0; i--)
 119     {
 120         if (line_is_blank (edit, i))
 121         {
 122             i++;
 123             break;
 124         }
 125         if (force)
 126         {
 127             if (bad_line_start (edit, line_start (edit, i)))
 128             {
 129                 i++;
 130                 break;
 131             }
 132         }
 133     }
 134     return edit_move_backward (edit, edit_bol (edit, edit->curs1), edit->curs_line - i);
 135 }
 136
 137 /* --------------------------------------------------------------------------------------------- */
 138 /**
 139  * Find the end of the current paragraph for the purpose of formatting.
 140  * Return position in the file.
 141  */
 142
 143 static long
 144 end_paragraph (WEdit * edit, int force)
 145 {
 146     int i;
 147     for (i = edit->curs_line + 1; i <= edit->total_lines; i++)
 148     {
 149         if (line_is_blank (edit, i))
 150         {
 151             i--;
 152             break;
 153         }
 154         if (force)
 155             if (bad_line_start (edit, line_start (edit, i)))
 156             {
 157                 i--;
 158                 break;
 159             }
 160     }
 161     return edit_eol (edit,
 162                      edit_move_forward (edit, edit_bol (edit, edit->curs1),
 163                                         i - edit->curs_line, 0));
 164 }
 165
 166 /* --------------------------------------------------------------------------------------------- */
 167
 168 static unsigned char *
 169 get_paragraph (WEdit * edit, long p, long q, int indent, int *size)
 170 {
 171     unsigned char *s, *t;
 172 #if 0
 173     t = g_try_malloc ((q - p) + 2 * (q - p) / option_word_wrap_line_length + 10);
 174 #else
 175     t = g_try_malloc (2 * (q - p) + 100);
 176 #endif
 177     if (t == NULL)
 178         return NULL;
 179     for (s = t; p < q; p++, s++)
 180     {
 181         if (indent)
 182             if (edit_get_byte (edit, p - 1) == '\n')
 183                 while (strchr ("\t ", edit_get_byte (edit, p)))
 184                     p++;
 185         *s = edit_get_byte (edit, p);
 186     }
 187     *size = (unsigned long) s - (unsigned long) t;
 188     t[*size] = '\n';
 189     return t;
 190 }
 191
 192 /* --------------------------------------------------------------------------------------------- */
 193
 194 static inline void
 195 strip_newlines (unsigned char *t, int size)
 196 {
 197     unsigned char *p = t;
 198     while (size-- != 0)
 199     {
 200         if (*p == '\n')
 201             *p = ' ';
 202         p++;
 203     }
 204 }
 205
 206 /* --------------------------------------------------------------------------------------------- */
 207 /**
 208    This function calculates the number of chars in a line specified to length l in pixels
 209  */
 210
 211 static inline int
 212 next_tab_pos (int x)
 213 {
 214     return x += tab_width - x % tab_width;
 215 }
 216
 217 /* --------------------------------------------------------------------------------------------- */
 218
 219 static inline int
 220 line_pixel_length (unsigned char *t, long b, int l)
 221 {
 222     int x = 0, c, xn = 0;
 223     for (;;)
 224     {
 225         c = t[b];
 226         switch (c)
 227         {
 228         case '\n':
 229             return b;
 230         case '\t':
 231             xn = next_tab_pos (x);
 232             break;
 233         default:
 234             xn = x + 1;
 235             break;
 236         }
 237         if (xn > l)
 238             break;
 239         x = xn;
 240         b++;
 241     }
 242     return b;
 243 }
 244
 245 /* --------------------------------------------------------------------------------------------- */
 246
 247 static int
 248 next_word_start (unsigned char *t, int q, int size)
 249 {
 250     int i;
 251     int saw_ws = 0;
 252
 253     for (i = q; i < size; i++)
 254     {
 255         switch (t[i])
 256         {
 257         case '\n':
 258             return -1;
 259         case '\t':
 260         case ' ':
 261             saw_ws = 1;
 262             break;
 263         default:
 264             if (saw_ws != 0)
 265                 return i;
 266             break;
 267         }
 268     }
 269     return -1;
 270 }
 271
 272 /* --------------------------------------------------------------------------------------------- */
 273 /** find the start of a word */
 274
 275 static inline int
 276 word_start (unsigned char *t, int q, int size)
 277 {
 278     int i = q;
 279     if (t[q] == ' ' || t[q] == '\t')
 280         return next_word_start (t, q, size);
 281     for (;;)
 282     {
 283         int c;
 284         if (!i)
 285             return -1;
 286         c = t[i - 1];
 287         if (c == '\n')
 288             return -1;
 289         if (c == ' ' || c == '\t')
 290             return i;
 291         i--;
 292     }
 293 }
 294
 295 /* --------------------------------------------------------------------------------------------- */
 296 /** replaces ' ' with '\n' to properly format a paragraph */
 297
 298 static inline void
 299 format_this (unsigned char *t, int size, int indent)
 300 {
 301     int q = 0, ww;
 302     strip_newlines (t, size);
 303     ww = option_word_wrap_line_length * FONT_MEAN_WIDTH - indent;
 304     if (ww < FONT_MEAN_WIDTH * 2)
 305         ww = FONT_MEAN_WIDTH * 2;
 306     for (;;)
 307     {
 308         int p;
 309         q = line_pixel_length (t, q, ww);
 310         if (q > size)
 311             break;
 312         if (t[q] == '\n')
 313             break;
 314         p = word_start (t, q, size);
 315         if (p == -1)
 316             q = next_word_start (t, q, size);   /* Return the end of the word if the beginning
 317                                                    of the word is at the beginning of a line
 318                                                    (i.e. a very long word) */
 319         else
 320             q = p;
 321         if (q == -1)            /* end of paragraph */
 322             break;
 323         if (q)
 324             t[q - 1] = '\n';
 325     }
 326 }
 327
 328 /* --------------------------------------------------------------------------------------------- */
 329
 330 static inline void
 331 replace_at (WEdit * edit, long q, int c)
 332 {
 333     edit_cursor_move (edit, q - edit->curs1);
 334     edit_delete (edit, 1);
 335     edit_insert_ahead (edit, c);
 336 }
 337
 338 /* --------------------------------------------------------------------------------------------- */
 339 /** replaces a block of text */
 340
 341 static inline void
 342 put_paragraph (WEdit * edit, unsigned char *t, long p, int indent, int size)
 343 {
 344     long cursor;
 345     int i, c = 0;
 346     cursor = edit->curs1;
 347     if (indent)
 348         while (strchr ("\t ", edit_get_byte (edit, p)))
 349             p++;
 350     for (i = 0; i < size; i++, p++)
 351     {
 352         if (i && indent)
 353         {
 354             if (t[i - 1] == '\n' && c == '\n')
 355             {
 356                 while (strchr ("\t ", edit_get_byte (edit, p)))
 357                     p++;
 358             }
 359             else if (t[i - 1] == '\n')
 360             {
 361                 long curs;
 362                 edit_cursor_move (edit, p - edit->curs1);
 363                 curs = edit->curs1;
 364                 edit_insert_indent (edit, indent);
 365                 if (cursor >= curs)
 366                     cursor += edit->curs1 - p;
 367                 p = edit->curs1;
 368             }
 369             else if (c == '\n')
 370             {
 371                 edit_cursor_move (edit, p - edit->curs1);
 372                 while (strchr ("\t ", edit_get_byte (edit, p)))
 373                 {
 374                     edit_delete (edit, 1);
 375                     if (cursor > edit->curs1)
 376                         cursor--;
 377                 }
 378                 p = edit->curs1;
 379             }
 380         }
 381         c = edit_get_byte (edit, p);
 382         if (c != t[i])
 383             replace_at (edit, p, t[i]);
 384     }
 385     edit_cursor_move (edit, cursor - edit->curs1);      /* restore cursor position */
 386 }
 387
 388 /* --------------------------------------------------------------------------------------------- */
 389
 390 static inline int
 391 test_indent (WEdit * edit, long p, long q)
 392 {
 393     int indent;
 394     indent = edit_indent_width (edit, p++);
 395     if (!indent)
 396         return 0;
 397     for (; p < q; p++)
 398         if (edit_get_byte (edit, p - 1) == '\n')
 399             if (indent != edit_indent_width (edit, p))
 400                 return 0;
 401     return indent;
 402 }
 403
 404 /* --------------------------------------------------------------------------------------------- */
 405 /*** public functions ****************************************************************************/
 406 /* --------------------------------------------------------------------------------------------- */
 407
 408 void
 409 format_paragraph (WEdit * edit, int force)
 410 {
 411     long p, q;
 412     int size;
 413     unsigned char *t;
 414     int indent = 0;
 415     if (option_word_wrap_line_length < 2)
 416         return;
 417     if (line_is_blank (edit, edit->curs_line))
 418         return;
 419     p = begin_paragraph (edit, force);
 420     q = end_paragraph (edit, force);
 421     indent = test_indent (edit, p, q);
 422     t = get_paragraph (edit, p, q, indent, &size);
 423     if (!t)
 424         return;
 425     if (!force)
 426     {
 427         int i;
 428         if (strchr (NO_FORMAT_CHARS_START, *t))
 429         {
 430             g_free (t);
 431             return;
 432         }
 433         for (i = 0; i < size - 1; i++)
 434         {
 435             if (t[i] == '\n')
 436             {
 437                 if (strchr (NO_FORMAT_CHARS_START "\t ", t[i + 1]))
 438                 {
 439                     g_free (t);
 440                     return;
 441                 }
 442             }
 443         }
 444     }
 445     format_this (t, q - p, indent);
 446     put_paragraph (edit, t, p, indent, size);
 447     g_free (t);
 448
 449     /* Scroll left as much as possible to show the formatted paragraph */
 450     edit_scroll_left (edit, -edit->start_col);
 451 }
 452
 453 /* --------------------------------------------------------------------------------------------- */