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 line_start (WEdit * edit, long line)
  31 {
  32     static long p = -1, l = 0;
  33     int c;
  34     if (p == -1 || abs (l - line) > abs (edit->curs_line - line)) {
  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     l = line;
  43     p = edit_bol (edit, p);
  44     while (strchr ("\t ", c = 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 static long begin_paragraph (WEdit * edit, long p, int force)
  71 {
  72     int i;
  73     for (i = edit->curs_line - 1; i > 0; i--) {
  74         if (line_is_blank (edit, i)) {
  75             i++;
  76             break;
  77         }
  78         if (force) {
  79             if (bad_line_start (edit, line_start (edit, i))) {
  80                 i++;
  81                 break;
  82             }
  83         }
  84     }
  85     return edit_move_backward (edit, edit_bol (edit, edit->curs1), edit->curs_line - i);
  86 }
  87
  88 static long end_paragraph (WEdit * edit, long p, int force)
  89 {
  90     int i;
  91     for (i = edit->curs_line + 1; i < edit->total_lines; i++) {
  92         if (line_is_blank (edit, i)) {
  93             i--;
  94             break;
  95         }
  96         if (force)
  97             if (bad_line_start (edit, line_start (edit, i))) {
  98                 i--;
  99                 break;
 100             }
 101     }
 102     return edit_eol (edit, edit_move_forward (edit, edit_bol (edit, edit->curs1), i - edit->curs_line, 0));
 103 }
 104
 105 static unsigned char *get_paragraph (WEdit * edit, long p, long q, int indent, int *size)
 106 {
 107     unsigned char *s, *t;
 108 #if 0
 109     t = malloc ((q - p) + 2 * (q - p) / option_word_wrap_line_length + 10);
 110 #else
 111     t = malloc (2 * (q - p) + 100);
 112 #endif
 113     if (!t)
 114         return 0;
 115     for (s = t; p < q; p++, s++) {
 116         if (indent)
 117             if (edit_get_byte (edit, p - 1) == '\n')
 118                 while (strchr ("\t ", edit_get_byte (edit, p)))
 119                     p++;
 120         *s = edit_get_byte (edit, p);
 121     }
 122     *size = (unsigned long) s - (unsigned long) t;
 123     t[*size] = '\n';
 124     return t;
 125 }
 126
 127 static void strip_newlines (unsigned char *t, int size)
 128 {
 129     unsigned char *p = t;
 130     while (size--) {
 131         *p = *p == '\n' ? ' ' : *p;
 132         p++;
 133     }
 134 }
 135
 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 (unsigned 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             xn = x + 1;
 160             break;
 161         }
 162         if (xn > l)
 163             break;
 164         x = xn;
 165         b++;
 166     }
 167     return b;
 168 }
 169
 170 /* find the start of a word */
 171 static int next_word_start (unsigned char *t, int q, int size)
 172 {
 173     int i;
 174     for (i = q;; i++) {
 175         switch (t[i]) {
 176         case '\n':
 177             return -1;
 178         case '\t':
 179         case ' ':
 180             for (;; i++) {
 181                 if (t[i] == '\n')
 182                     return -1;
 183                 if (t[i] != ' ' && t[i] != '\t')
 184                     return i;
 185             }
 186             break;
 187         }
 188     }
 189 }
 190
 191 /* find the start of a word */
 192 static int word_start (unsigned char *t, int q, int size)
 193 {
 194     int i = q;
 195     if (t[q] == ' ' || t[q] == '\t')
 196         return next_word_start (t, q, size);
 197     for (;;) {
 198         int c;
 199         if (!i)
 200             return -1;
 201         c = t[i - 1];
 202         if (c == '\n')
 203             return -1;
 204         if (c == ' ' || c == '\t')
 205             return i;
 206         i--;
 207     }
 208 }
 209
 210 /* replaces ' ' with '\n' to properly format a paragraph */
 211 static void format_this (unsigned char *t, int size, int indent)
 212 {
 213     int q = 0, ww;
 214     strip_newlines (t, size);
 215     ww = option_word_wrap_line_length * FONT_MEAN_WIDTH - indent;
 216     if (ww < FONT_MEAN_WIDTH * 2)
 217         ww = FONT_MEAN_WIDTH * 2;
 218     for (;;) {
 219         int p;
 220         q = line_pixel_length (t, q, ww);
 221         if (q > size)
 222             break;
 223         if (t[q] == '\n')
 224             break;
 225         p = word_start (t, q, size);
 226         if (p == -1)
 227             q = next_word_start (t, q, size);   /* Return the end of the word if the beginning
 228                                                    of the word is at the beginning of a line
 229                                                    (i.e. a very long word) */
 230         else
 231             q = p;
 232         if (q == -1)    /* end of paragraph */
 233             break;
 234         if (q)
 235             t[q - 1] = '\n';
 236     }
 237 }
 238
 239 static void replace_at (WEdit * edit, long q, int c)
 240 {
 241     edit_cursor_move (edit, q - edit->curs1);
 242     edit_delete (edit);
 243     edit_insert_ahead (edit, c);
 244 }
 245
 246 void edit_insert_indent (WEdit * edit, int indent);
 247
 248 /* replaces a block of text */
 249 static void put_paragraph (WEdit * edit, unsigned char *t, long p, long q, int indent, int size)
 250 {
 251     long cursor;
 252     int i, c = 0;
 253     cursor = edit->curs1;
 254     if (indent)
 255         while (strchr ("\t ", edit_get_byte (edit, p)))
 256             p++;
 257     for (i = 0; i < size; i++, p++) {
 258         if (i && indent) {
 259             if (t[i - 1] == '\n' && c == '\n') {
 260                 while (strchr ("\t ", edit_get_byte (edit, p)))
 261                     p++;
 262             } else if (t[i - 1] == '\n') {
 263                 long curs;
 264                 edit_cursor_move (edit, p - edit->curs1);
 265                 curs = edit->curs1;
 266                 edit_insert_indent (edit, indent);
 267                 if (cursor >= curs)
 268                     cursor += edit->curs1 - p;
 269                 p = edit->curs1;
 270             } else if (c == '\n') {
 271                 edit_cursor_move (edit, p - edit->curs1);
 272                 while (strchr ("\t ", edit_get_byte (edit, p))) {
 273                     edit_delete (edit);
 274                     if (cursor > edit->curs1)
 275                         cursor--;
 276                 }
 277                 p = edit->curs1;
 278             }
 279         }
 280         c = edit_get_byte (edit, p);
 281         if (c != t[i])
 282             replace_at (edit, p, t[i]);
 283     }
 284     edit_cursor_move (edit, cursor - edit->curs1);      /* restore cursor position */
 285 }
 286
 287 int edit_indent_width (WEdit * edit, long p);
 288
 289 static int test_indent (WEdit * edit, long p, long q)
 290 {
 291     int indent;
 292     indent = edit_indent_width (edit, p++);
 293     if (!indent)
 294         return 0;
 295     for (; p < q; p++)
 296         if (edit_get_byte (edit, p - 1) == '\n')
 297             if (indent != edit_indent_width (edit, p))
 298                 return 0;
 299     return indent;
 300 }
 301
 302 void format_paragraph (WEdit * edit, int force)
 303 {
 304     long p, q;
 305     int size;
 306     unsigned char *t;
 307     int indent = 0;
 308     if (option_word_wrap_line_length < 2)
 309         return;
 310     if (line_is_blank (edit, edit->curs_line))
 311         return;
 312     p = begin_paragraph (edit, edit->curs1, force);
 313     q = end_paragraph (edit, edit->curs1, force);
 314     indent = test_indent (edit, p, q);
 315     t = get_paragraph (edit, p, q, indent, &size);
 316     if (!t)
 317         return;
 318     if (!force) {
 319         int i;
 320         if (strchr (NO_FORMAT_CHARS_START, *t)) {
 321             free (t);
 322             return;
 323         }
 324         for (i = 0; i < size - 1; i++) {
 325             if (t[i] == '\n') {
 326                 if (strchr (NO_FORMAT_CHARS_START "\t ", t[i + 1])) {
 327                     free (t);
 328                     return;
 329                 }
 330             }
 331         }
 332     }
 333     format_this (t, q - p, indent);
 334     put_paragraph (edit, t, p, q, indent, size);
 335     free (t);
 336 }