src/editor/wordproc.c

   1 /*
   2    Word-processor mode for the editor: does dynamic
   3    paragraph formatting.
   4
   5    Copyright (C) 2011
   6    The Free Software Foundation, Inc.
   7
   8    Copyright (C) 1996 Paul Sheer
   9
  10    Writen by:
  11    Paul Sheer, 1996
  12
  13    This file is part of the Midnight Commander.
  14
  15    The Midnight Commander is free software: you can redistribute it
  16    and/or modify it under the terms of the GNU General Public License as
  17    published by the Free Software Foundation, either version 3 of the License,
  18    or (at your option) any later version.
  19
  20    The Midnight Commander is distributed in the hope that it will be useful,
  21    but WITHOUT ANY WARRANTY; without even the implied warranty of
  22    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23    GNU General Public License for more details.
  24
  25    You should have received a copy of the GNU General Public License
  26    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  27  */
  28
  29 /** \file
  30  *  \brief Source: word-processor mode for the editor: does dynamic paragraph formatting
  31  *  \author Paul Sheer
  32  *  \date 1996
  33  */
  34
  35 #include <config.h>
  36
  37 #include <stdio.h>
  38 #include <stdarg.h>
  39 #include <sys/types.h>
  40 #include <unistd.h>
  41 #include <string.h>
  42 #include <ctype.h>
  43 #include <errno.h>
  44 #include <sys/stat.h>
  45
  46 #include <stdlib.h>
  47
  48 #include "lib/global.h"
  49
  50 #include "src/setup.h"          /* option_tab_spacing */
  51
  52 #include "edit-impl.h"
  53 #include "editwidget.h"
  54
  55 /*** global variables ****************************************************************************/
  56
  57 /*** file scope macro definitions ****************************************************************/
  58
  59 #define tab_width option_tab_spacing
  60
  61 #define NO_FORMAT_CHARS_START "-+*\\,.;:&>"
  62 #define FONT_MEAN_WIDTH 1
  63
  64 /*** file scope type declarations ****************************************************************/
  65
  66 /*** file scope variables ************************************************************************/
  67
  68 /*** file scope functions ************************************************************************/
  69 /* --------------------------------------------------------------------------------------------- */
  70
  71 static long
  72 line_start (WEdit * edit, long line)
  73 {
  74     off_t p;
  75     long l;
  76
  77     l = edit->curs_line;
  78     p = edit->curs1;
  79
  80     if (line < l)
  81         p = edit_move_backward (edit, p, l - line);
  82     else if (line > l)
  83         p = edit_move_forward (edit, p, line - l, 0);
  84
  85     p = edit_bol (edit, p);
  86     while (strchr ("\t ", edit_get_byte (edit, p)))
  87         p++;
  88     return p;
  89 }
  90
  91 /* --------------------------------------------------------------------------------------------- */
  92
  93 static int
  94 bad_line_start (WEdit * edit, off_t p)
  95 {
  96     int c;
  97     c = edit_get_byte (edit, p);
  98     if (c == '.')
  99     {                           /* `...' is acceptable */
 100         if (edit_get_byte (edit, p + 1) == '.')
 101             if (edit_get_byte (edit, p + 2) == '.')
 102                 return 0;
 103         return 1;
 104     }
 105     if (c == '-')
 106     {
 107         if (edit_get_byte (edit, p + 1) == '-')
 108             if (edit_get_byte (edit, p + 2) == '-')
 109                 return 0;       /* `---' is acceptable */
 110         return 1;
 111     }
 112     if (strchr (NO_FORMAT_CHARS_START, c))
 113         return 1;
 114     return 0;
 115 }
 116
 117 /* --------------------------------------------------------------------------------------------- */
 118 /**
 119  * Find the start of the current paragraph for the purpose of formatting.
 120  * Return position in the file.
 121  */
 122
 123 static long
 124 begin_paragraph (WEdit * edit, int force)
 125 {
 126     long i;
 127     for (i = edit->curs_line - 1; i >= 0; i--)
 128     {
 129         if (line_is_blank (edit, i))
 130         {
 131             i++;
 132             break;
 133         }
 134         if (force)
 135         {
 136             if (bad_line_start (edit, line_start (edit, i)))
 137             {
 138                 i++;
 139                 break;
 140             }
 141         }
 142     }
 143     return edit_move_backward (edit, edit_bol (edit, edit->curs1), edit->curs_line - i);
 144 }
 145
 146 /* --------------------------------------------------------------------------------------------- */
 147 /**
 148  * Find the end of the current paragraph for the purpose of formatting.
 149  * Return position in the file.
 150  */
 151
 152 static long
 153 end_paragraph (WEdit * edit, int force)
 154 {
 155     long i;
 156     for (i = edit->curs_line + 1; i <= edit->total_lines; i++)
 157     {
 158         if (line_is_blank (edit, i))
 159         {
 160             i--;
 161             break;
 162         }
 163         if (force)
 164             if (bad_line_start (edit, line_start (edit, i)))
 165             {
 166                 i--;
 167                 break;
 168             }
 169     }
 170     return edit_eol (edit,
 171                      edit_move_forward (edit, edit_bol (edit, edit->curs1),
 172                                         i - edit->curs_line, 0));
 173 }
 174
 175 /* --------------------------------------------------------------------------------------------- */
 176
 177 static unsigned char *
 178 get_paragraph (WEdit * edit, off_t p, off_t q, int indent, int *size)
 179 {
 180     unsigned char *s, *t;
 181 #if 0
 182     t = g_try_malloc ((q - p) + 2 * (q - p) / option_word_wrap_line_length + 10);
 183 #else
 184     t = g_try_malloc (2 * (q - p) + 100);
 185 #endif
 186     if (t == NULL)
 187         return NULL;
 188     for (s = t; p < q; p++, s++)
 189     {
 190         if (indent)
 191             if (edit_get_byte (edit, p - 1) == '\n')
 192                 while (strchr ("\t ", edit_get_byte (edit, p)))
 193                     p++;
 194         *s = edit_get_byte (edit, p);
 195     }
 196     *size = (unsigned long) (s - t);
 197     /* FIXME: all variables related to 'size' should be fixed */
 198     t[*size] = '\n';
 199     return t;
 200 }
 201
 202 /* --------------------------------------------------------------------------------------------- */
 203
 204 static inline void
 205 strip_newlines (unsigned char *t, int size)
 206 {
 207     unsigned char *p = t;
 208     while (size-- != 0)
 209     {
 210         if (*p == '\n')
 211             *p = ' ';
 212         p++;
 213     }
 214 }
 215
 216 /* --------------------------------------------------------------------------------------------- */
 217 /**
 218    This function calculates the number of chars in a line specified to length l in pixels
 219  */
 220
 221 static inline int
 222 next_tab_pos (int x)
 223 {
 224     return x += tab_width - x % tab_width;
 225 }
 226
 227 /* --------------------------------------------------------------------------------------------- */
 228
 229 static inline int
 230 line_pixel_length (unsigned char *t, long b, int l)
 231 {
 232     int x = 0, c, xn = 0;
 233     for (;;)
 234     {
 235         c = t[b];
 236         switch (c)
 237         {
 238         case '\n':
 239             return b;
 240         case '\t':
 241             xn = next_tab_pos (x);
 242             break;
 243         default:
 244             xn = x + 1;
 245             break;
 246         }
 247         if (xn > l)
 248             break;
 249         x = xn;
 250         b++;
 251     }
 252     return b;
 253 }
 254
 255 /* --------------------------------------------------------------------------------------------- */
 256
 257 static int
 258 next_word_start (unsigned char *t, int q, int size)
 259 {
 260     int i;
 261     int saw_ws = 0;
 262
 263     for (i = q; i < size; i++)
 264     {
 265         switch (t[i])
 266         {
 267         case '\n':
 268             return -1;
 269         case '\t':
 270         case ' ':
 271             saw_ws = 1;
 272             break;
 273         default:
 274             if (saw_ws != 0)
 275                 return i;
 276             break;
 277         }
 278     }
 279     return -1;
 280 }
 281
 282 /* --------------------------------------------------------------------------------------------- */
 283 /** find the start of a word */
 284
 285 static inline int
 286 word_start (unsigned char *t, int q, int size)
 287 {
 288     int i = q;
 289     if (t[q] == ' ' || t[q] == '\t')
 290         return next_word_start (t, q, size);
 291     for (;;)
 292     {
 293         int c;
 294         if (!i)
 295             return -1;
 296         c = t[i - 1];
 297         if (c == '\n')
 298             return -1;
 299         if (c == ' ' || c == '\t')
 300             return i;
 301         i--;
 302     }
 303 }
 304
 305 /* --------------------------------------------------------------------------------------------- */
 306 /** replaces ' ' with '\n' to properly format a paragraph */
 307
 308 static inline void
 309 format_this (unsigned char *t, int size, int indent)
 310 {
 311     int q = 0, ww;
 312     strip_newlines (t, size);
 313     ww = option_word_wrap_line_length * FONT_MEAN_WIDTH - indent;
 314     if (ww < FONT_MEAN_WIDTH * 2)
 315         ww = FONT_MEAN_WIDTH * 2;
 316     for (;;)
 317     {
 318         int p;
 319         q = line_pixel_length (t, q, ww);
 320         if (q > size)
 321             break;
 322         if (t[q] == '\n')
 323             break;
 324         p = word_start (t, q, size);
 325         if (p == -1)
 326             q = next_word_start (t, q, size);   /* Return the end of the word if the beginning
 327                                                    of the word is at the beginning of a line
 328                                                    (i.e. a very long word) */
 329         else
 330             q = p;
 331         if (q == -1)            /* end of paragraph */
 332             break;
 333         if (q)
 334             t[q - 1] = '\n';
 335     }
 336 }
 337
 338 /* --------------------------------------------------------------------------------------------- */
 339
 340 static inline void
 341 replace_at (WEdit * edit, long q, int c)
 342 {
 343     edit_cursor_move (edit, q - edit->curs1);
 344     edit_delete (edit, TRUE);
 345     edit_insert_ahead (edit, c);
 346 }
 347
 348 /* --------------------------------------------------------------------------------------------- */
 349 /** replaces a block of text */
 350
 351 static inline void
 352 put_paragraph (WEdit * edit, unsigned char *t, off_t p, int indent, int size)
 353 {
 354     long cursor;
 355     int i, c = 0;
 356     cursor = edit->curs1;
 357     if (indent)
 358         while (strchr ("\t ", edit_get_byte (edit, p)))
 359             p++;
 360     for (i = 0; i < size; i++, p++)
 361     {
 362         if (i && indent)
 363         {
 364             if (t[i - 1] == '\n' && c == '\n')
 365             {
 366                 while (strchr ("\t ", edit_get_byte (edit, p)))
 367                     p++;
 368             }
 369             else if (t[i - 1] == '\n')
 370             {
 371                 off_t curs;
 372                 edit_cursor_move (edit, p - edit->curs1);
 373                 curs = edit->curs1;
 374                 edit_insert_indent (edit, indent);
 375                 if (cursor >= curs)
 376                     cursor += edit->curs1 - p;
 377                 p = edit->curs1;
 378             }
 379             else if (c == '\n')
 380             {
 381                 edit_cursor_move (edit, p - edit->curs1);
 382                 while (strchr ("\t ", edit_get_byte (edit, p)))
 383                 {
 384                     edit_delete (edit, TRUE);
 385                     if (cursor > edit->curs1)
 386                         cursor--;
 387                 }
 388                 p = edit->curs1;
 389             }
 390         }
 391         c = edit_get_byte (edit, p);
 392         if (c != t[i])
 393             replace_at (edit, p, t[i]);
 394     }
 395     edit_cursor_move (edit, cursor - edit->curs1);      /* restore cursor position */
 396 }
 397
 398 /* --------------------------------------------------------------------------------------------- */
 399
 400 static inline int
 401 test_indent (WEdit * edit, off_t p, off_t q)
 402 {
 403     int indent;
 404     indent = edit_indent_width (edit, p++);
 405     if (!indent)
 406         return 0;
 407     for (; p < q; p++)
 408         if (edit_get_byte (edit, p - 1) == '\n')
 409             if (indent != edit_indent_width (edit, p))
 410                 return 0;
 411     return indent;
 412 }
 413
 414 /* --------------------------------------------------------------------------------------------- */
 415 /*** public functions ****************************************************************************/
 416 /* --------------------------------------------------------------------------------------------- */
 417
 418 void
 419 format_paragraph (WEdit * edit, int force)
 420 {
 421     long p, q;
 422     int size;
 423     unsigned char *t;
 424     int indent = 0;
 425     if (option_word_wrap_line_length < 2)
 426         return;
 427     if (line_is_blank (edit, edit->curs_line))
 428         return;
 429     p = begin_paragraph (edit, force);
 430     q = end_paragraph (edit, force);
 431     indent = test_indent (edit, p, q);
 432     t = get_paragraph (edit, p, q, indent, &size);
 433     if (!t)
 434         return;
 435     if (!force)
 436     {
 437         int i;
 438         if (strchr (NO_FORMAT_CHARS_START, *t))
 439         {
 440             g_free (t);
 441             return;
 442         }
 443         for (i = 0; i < size - 1; i++)
 444         {
 445             if (t[i] == '\n')
 446             {
 447                 if (strchr (NO_FORMAT_CHARS_START "\t ", t[i + 1]))
 448                 {
 449                     g_free (t);
 450                     return;
 451                 }
 452             }
 453         }
 454     }
 455     format_this (t, q - p, indent);
 456     put_paragraph (edit, t, p, indent, size);
 457     g_free (t);
 458
 459     /* Scroll left as much as possible to show the formatted paragraph */
 460     edit_scroll_left (edit, -edit->start_col);
 461 }
 462
 463 /* --------------------------------------------------------------------------------------------- */