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