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)
 202 {
 203     int i;
 204     for (i = q;; i++) {
 205         switch (t[i]) {
 206         case '\n':
 207             return -1;
 208         case '\t':
 209         case ' ':
 210             for (;; i++) {
 211                 if (t[i] == '\n')
 212                     return -1;
 213                 if (t[i] != ' ' && t[i] != '\t')
 214                     return i;
 215             }
 216             break;
 217         }
 218     }
 219 }
 220
 221 /* find the start of a word */
 222 static int
 223 word_start (unsigned char *t, int q)
 224 {
 225     int i = q;
 226     if (t[q] == ' ' || t[q] == '\t')
 227         return next_word_start (t, q);
 228     for (;;) {
 229         int c;
 230         if (!i)
 231             return -1;
 232         c = t[i - 1];
 233         if (c == '\n')
 234             return -1;
 235         if (c == ' ' || c == '\t')
 236             return i;
 237         i--;
 238     }
 239 }
 240
 241 /* replaces ' ' with '\n' to properly format a paragraph */
 242 static void format_this (unsigned char *t, int size, int indent)
 243 {
 244     int q = 0, ww;
 245     strip_newlines (t, size);
 246     ww = option_word_wrap_line_length * FONT_MEAN_WIDTH - indent;
 247     if (ww < FONT_MEAN_WIDTH * 2)
 248         ww = FONT_MEAN_WIDTH * 2;
 249     for (;;) {
 250         int p;
 251         q = line_pixel_length (t, q, ww);
 252         if (q > size)
 253             break;
 254         if (t[q] == '\n')
 255             break;
 256         p = word_start (t, q);
 257         if (p == -1)
 258             q = next_word_start (t, q);         /* Return the end of the word if the beginning
 259                                                    of the word is at the beginning of a line
 260                                                    (i.e. a very long word) */
 261         else
 262             q = p;
 263         if (q == -1)    /* end of paragraph */
 264             break;
 265         if (q)
 266             t[q - 1] = '\n';
 267     }
 268 }
 269
 270 static void replace_at (WEdit * edit, long q, int c)
 271 {
 272     edit_cursor_move (edit, q - edit->curs1);
 273     edit_delete (edit);
 274     edit_insert_ahead (edit, c);
 275 }
 276
 277 /* replaces a block of text */
 278 static void
 279 put_paragraph (WEdit * edit, unsigned char *t, long p, int indent, int size)
 280 {
 281     long cursor;
 282     int i, c = 0;
 283     cursor = edit->curs1;
 284     if (indent)
 285         while (strchr ("\t ", edit_get_byte (edit, p)))
 286             p++;
 287     for (i = 0; i < size; i++, p++) {
 288         if (i && indent) {
 289             if (t[i - 1] == '\n' && c == '\n') {
 290                 while (strchr ("\t ", edit_get_byte (edit, p)))
 291                     p++;
 292             } else if (t[i - 1] == '\n') {
 293                 long curs;
 294                 edit_cursor_move (edit, p - edit->curs1);
 295                 curs = edit->curs1;
 296                 edit_insert_indent (edit, indent);
 297                 if (cursor >= curs)
 298                     cursor += edit->curs1 - p;
 299                 p = edit->curs1;
 300             } else if (c == '\n') {
 301                 edit_cursor_move (edit, p - edit->curs1);
 302                 while (strchr ("\t ", edit_get_byte (edit, p))) {
 303                     edit_delete (edit);
 304                     if (cursor > edit->curs1)
 305                         cursor--;
 306                 }
 307                 p = edit->curs1;
 308             }
 309         }
 310         c = edit_get_byte (edit, p);
 311         if (c != t[i])
 312             replace_at (edit, p, t[i]);
 313     }
 314     edit_cursor_move (edit, cursor - edit->curs1);      /* restore cursor position */
 315 }
 316
 317 static int test_indent (WEdit * edit, long p, long q)
 318 {
 319     int indent;
 320     indent = edit_indent_width (edit, p++);
 321     if (!indent)
 322         return 0;
 323     for (; p < q; p++)
 324         if (edit_get_byte (edit, p - 1) == '\n')
 325             if (indent != edit_indent_width (edit, p))
 326                 return 0;
 327     return indent;
 328 }
 329
 330 void
 331 format_paragraph (WEdit *edit, int force)
 332 {
 333     long p, q;
 334     int size;
 335     unsigned char *t;
 336     int indent = 0;
 337     if (option_word_wrap_line_length < 2)
 338         return;
 339     if (line_is_blank (edit, edit->curs_line))
 340         return;
 341     p = begin_paragraph (edit, force);
 342     q = end_paragraph (edit, force);
 343     indent = test_indent (edit, p, q);
 344     t = get_paragraph (edit, p, q, indent, &size);
 345     if (!t)
 346         return;
 347     if (!force) {
 348         int i;
 349         if (strchr (NO_FORMAT_CHARS_START, *t)) {
 350             g_free (t);
 351             return;
 352         }
 353         for (i = 0; i < size - 1; i++) {
 354             if (t[i] == '\n') {
 355                 if (strchr (NO_FORMAT_CHARS_START "\t ", t[i + 1])) {
 356                     g_free (t);
 357                     return;
 358                 }
 359             }
 360         }
 361     }
 362     format_this (t, q - p, indent);
 363     put_paragraph (edit, t, p, indent, size);
 364     g_free (t);
 365
 366     /* Scroll left as much as possible to show the formatted paragraph */
 367     edit_scroll_left (edit, -edit->start_col);
 368 }