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 #include "edit-widget.h"
  24
  25 #define tab_width option_tab_spacing
  26
  27 #define NO_FORMAT_CHARS_START "-+*\\,.;:&>"
  28 #define FONT_MEAN_WIDTH 1
  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 *
 119 get_paragraph (WEdit *edit, long p, long q, int indent, int *size)
 120 {
 121     unsigned char *s, *t;
 122 #if 0
 123     t = g_malloc ((q - p) + 2 * (q - p) / option_word_wrap_line_length +
 124                   10);
 125 #else
 126     t = g_malloc (2 * (q - p) + 100);
 127 #endif
 128     if (!t)
 129         return 0;
 130     for (s = t; p < q; p++, s++) {
 131         if (indent)
 132             if (edit_get_byte (edit, p - 1) == '\n')
 133                 while (strchr ("\t ", edit_get_byte (edit, p)))
 134                     p++;
 135         *s = edit_get_byte (edit, p);
 136     }
 137     *size = (unsigned long) s - (unsigned long) t;
 138     t[*size] = '\n';
 139     return t;
 140 }
 141
 142 static void strip_newlines (unsigned char *t, int size)
 143 {
 144     unsigned char *p = t;
 145     while (size--) {
 146         *p = *p == '\n' ? ' ' : *p;
 147         p++;
 148     }
 149 }
 150
 151 /*
 152    This is a copy of the function
 153    int calc_text_pos (WEdit * edit, long b, long *q, int l)
 154    in propfont.c  :(
 155    It calculates the number of chars in a line specified to length l in pixels
 156  */
 157 static inline int next_tab_pos (int x)
 158 {
 159     return x += tab_width - x % tab_width;
 160 }
 161 static int line_pixel_length (unsigned char *t, long b, int l)
 162 {
 163     int x = 0, c, xn = 0;
 164     for (;;) {
 165         c = t[b];
 166         switch (c) {
 167         case '\n':
 168             return b;
 169         case '\t':
 170             xn = next_tab_pos (x);
 171             break;
 172         default:
 173             xn = x + 1;
 174             break;
 175         }
 176         if (xn > l)
 177             break;
 178         x = xn;
 179         b++;
 180     }
 181     return b;
 182 }
 183
 184 /* find the start of a word */
 185 static int next_word_start (unsigned char *t, int q, int size)
 186 {
 187     int i;
 188     for (i = q;; i++) {
 189         switch (t[i]) {
 190         case '\n':
 191             return -1;
 192         case '\t':
 193         case ' ':
 194             for (;; i++) {
 195                 if (t[i] == '\n')
 196                     return -1;
 197                 if (t[i] != ' ' && t[i] != '\t')
 198                     return i;
 199             }
 200             break;
 201         }
 202     }
 203 }
 204
 205 /* find the start of a word */
 206 static int word_start (unsigned char *t, int q, int size)
 207 {
 208     int i = q;
 209     if (t[q] == ' ' || t[q] == '\t')
 210         return next_word_start (t, q, size);
 211     for (;;) {
 212         int c;
 213         if (!i)
 214             return -1;
 215         c = t[i - 1];
 216         if (c == '\n')
 217             return -1;
 218         if (c == ' ' || c == '\t')
 219             return i;
 220         i--;
 221     }
 222 }
 223
 224 /* replaces ' ' with '\n' to properly format a paragraph */
 225 static void format_this (unsigned char *t, int size, int indent)
 226 {
 227     int q = 0, ww;
 228     strip_newlines (t, size);
 229     ww = option_word_wrap_line_length * FONT_MEAN_WIDTH - indent;
 230     if (ww < FONT_MEAN_WIDTH * 2)
 231         ww = FONT_MEAN_WIDTH * 2;
 232     for (;;) {
 233         int p;
 234         q = line_pixel_length (t, q, ww);
 235         if (q > size)
 236             break;
 237         if (t[q] == '\n')
 238             break;
 239         p = word_start (t, q, size);
 240         if (p == -1)
 241             q = next_word_start (t, q, size);   /* Return the end of the word if the beginning
 242                                                    of the word is at the beginning of a line
 243                                                    (i.e. a very long word) */
 244         else
 245             q = p;
 246         if (q == -1)    /* end of paragraph */
 247             break;
 248         if (q)
 249             t[q - 1] = '\n';
 250     }
 251 }
 252
 253 static void replace_at (WEdit * edit, long q, int c)
 254 {
 255     edit_cursor_move (edit, q - edit->curs1);
 256     edit_delete (edit);
 257     edit_insert_ahead (edit, c);
 258 }
 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 static int test_indent (WEdit * edit, long p, long q)
 300 {
 301     int indent;
 302     indent = edit_indent_width (edit, p++);
 303     if (!indent)
 304         return 0;
 305     for (; p < q; p++)
 306         if (edit_get_byte (edit, p - 1) == '\n')
 307             if (indent != edit_indent_width (edit, p))
 308                 return 0;
 309     return indent;
 310 }
 311
 312 void
 313 format_paragraph (WEdit *edit, int force)
 314 {
 315     long p, q;
 316     int size;
 317     unsigned char *t;
 318     int indent = 0;
 319     if (option_word_wrap_line_length < 2)
 320         return;
 321     if (line_is_blank (edit, edit->curs_line))
 322         return;
 323     p = begin_paragraph (edit, force);
 324     q = end_paragraph (edit, force);
 325     indent = test_indent (edit, p, q);
 326     t = get_paragraph (edit, p, q, indent, &size);
 327     if (!t)
 328         return;
 329     if (!force) {
 330         int i;
 331         if (strchr (NO_FORMAT_CHARS_START, *t)) {
 332             g_free (t);
 333             return;
 334         }
 335         for (i = 0; i < size - 1; i++) {
 336             if (t[i] == '\n') {
 337                 if (strchr (NO_FORMAT_CHARS_START "\t ", t[i + 1])) {
 338                     g_free (t);
 339                     return;
 340                 }
 341             }
 342         }
 343     }
 344     format_this (t, q - p, indent);
 345     put_paragraph (edit, t, p, q, indent, size);
 346     g_free (t);
 347
 348     /* Scroll left as much as possible to show the formatted paragraph */
 349     edit_scroll_left (edit, -edit->start_col);
 350 }