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 #include <stdlib.h>
  34
  35 #include <mhl/memory.h>
  36
  37 #include "../src/global.h"
  38
  39 #include "edit.h"
  40 #include "edit-widget.h"
  41
  42 #define tab_width option_tab_spacing
  43
  44 #define NO_FORMAT_CHARS_START "-+*\\,.;:&>"
  45 #define FONT_MEAN_WIDTH 1
  46
  47 static long
  48 line_start (WEdit *edit, long line)
  49 {
  50     long p, l;
  51
  52     l = edit->curs_line;
  53     p = edit->curs1;
  54
  55     if (line < l)
  56         p = edit_move_backward (edit, p, l - line);
  57     else if (line > l)
  58         p = edit_move_forward (edit, p, line - l, 0);
  59
  60     p = edit_bol (edit, p);
  61     while (strchr ("\t ", edit_get_byte (edit, p)))
  62         p++;
  63     return p;
  64 }
  65
  66 static int bad_line_start (WEdit * edit, long p)
  67 {
  68     int c;
  69     c = edit_get_byte (edit, p);
  70     if (c == '.') {             /* `...' is acceptable */
  71         if (edit_get_byte (edit, p + 1) == '.')
  72             if (edit_get_byte (edit, p + 2) == '.')
  73                 return 0;
  74         return 1;
  75     }
  76     if (c == '-') {
  77         if (edit_get_byte (edit, p + 1) == '-')
  78             if (edit_get_byte (edit, p + 2) == '-')
  79                 return 0;       /* `---' is acceptable */
  80         return 1;
  81     }
  82     if (strchr (NO_FORMAT_CHARS_START, c))
  83         return 1;
  84     return 0;
  85 }
  86
  87 /*
  88  * Find the start of the current paragraph for the purpose of formatting.
  89  * Return position in the file.
  90  */
  91 static long
  92 begin_paragraph (WEdit *edit, int force)
  93 {
  94     int i;
  95     for (i = edit->curs_line - 1; i >= 0; i--) {
  96         if (line_is_blank (edit, i)) {
  97             i++;
  98             break;
  99         }
 100         if (force) {
 101             if (bad_line_start (edit, line_start (edit, i))) {
 102                 i++;
 103                 break;
 104             }
 105         }
 106     }
 107     return edit_move_backward (edit, edit_bol (edit, edit->curs1),
 108                                edit->curs_line - i);
 109 }
 110
 111 /*
 112  * Find the end of the current paragraph for the purpose of formatting.
 113  * Return position in the file.
 114  */
 115 static long
 116 end_paragraph (WEdit *edit, int force)
 117 {
 118     int i;
 119     for (i = edit->curs_line + 1; i <= edit->total_lines; i++) {
 120         if (line_is_blank (edit, i)) {
 121             i--;
 122             break;
 123         }
 124         if (force)
 125             if (bad_line_start (edit, line_start (edit, i))) {
 126                 i--;
 127                 break;
 128             }
 129     }
 130     return edit_eol (edit,
 131                      edit_move_forward (edit, edit_bol (edit, edit->curs1),
 132                                         i - edit->curs_line, 0));
 133 }
 134
 135 static unsigned char *
 136 get_paragraph (WEdit *edit, long p, long q, int indent, int *size)
 137 {
 138     unsigned char *s, *t;
 139 #if 0
 140     t = g_malloc ((q - p) + 2 * (q - p) / option_word_wrap_line_length +
 141                   10);
 142 #else
 143     t = g_malloc (2 * (q - p) + 100);
 144 #endif
 145     if (!t)
 146         return 0;
 147     for (s = t; p < q; p++, s++) {
 148         if (indent)
 149             if (edit_get_byte (edit, p - 1) == '\n')
 150                 while (strchr ("\t ", edit_get_byte (edit, p)))
 151                     p++;
 152         *s = edit_get_byte (edit, p);
 153     }
 154     *size = (unsigned long) s - (unsigned long) t;
 155     t[*size] = '\n';
 156     return t;
 157 }
 158
 159 static void strip_newlines (unsigned char *t, int size)
 160 {
 161     unsigned char *p = t;
 162     while (size--) {
 163         *p = *p == '\n' ? ' ' : *p;
 164         p++;
 165     }
 166 }
 167
 168 /*
 169    This is a copy of the function
 170    int calc_text_pos (WEdit * edit, long b, long *q, int l)
 171    in propfont.c  :(
 172    It calculates the number of chars in a line specified to length l in pixels
 173  */
 174 static inline int next_tab_pos (int x)
 175 {
 176     return x += tab_width - x % tab_width;
 177 }
 178 static int line_pixel_length (unsigned char *t, long b, int l)
 179 {
 180     int x = 0, c, xn = 0;
 181     for (;;) {
 182         c = t[b];
 183         switch (c) {
 184         case '\n':
 185             return b;
 186         case '\t':
 187             xn = next_tab_pos (x);
 188             break;
 189         default:
 190             xn = x + 1;
 191             break;
 192         }
 193         if (xn > l)
 194             break;
 195         x = xn;
 196         b++;
 197     }
 198     return b;
 199 }
 200
 201 static int
 202 next_word_start (unsigned char *t, int q, int size)
 203 {
 204     int i;
 205     int saw_ws = 0;
 206
 207     for (i = q; i < size; i++) {
 208         switch (t[i]) {
 209         case '\n':
 210             return -1;
 211         case '\t':
 212         case ' ':
 213             saw_ws = 1;
 214             break;
 215         default:
 216             if (saw_ws != 0)
 217                 return i;
 218             break;
 219         }
 220     }
 221     return -1;
 222 }
 223
 224 /* find the start of a word */
 225 static int
 226 word_start (unsigned char *t, int q, int size)
 227 {
 228     int i = q;
 229     if (t[q] == ' ' || t[q] == '\t')
 230         return next_word_start (t, q, size);
 231     for (;;) {
 232         int c;
 233         if (!i)
 234             return -1;
 235         c = t[i - 1];
 236         if (c == '\n')
 237             return -1;
 238         if (c == ' ' || c == '\t')
 239             return i;
 240         i--;
 241     }
 242 }
 243
 244 /* replaces ' ' with '\n' to properly format a paragraph */
 245 static void format_this (unsigned char *t, int size, int indent)
 246 {
 247     int q = 0, ww;
 248     strip_newlines (t, size);
 249     ww = option_word_wrap_line_length * FONT_MEAN_WIDTH - indent;
 250     if (ww < FONT_MEAN_WIDTH * 2)
 251         ww = FONT_MEAN_WIDTH * 2;
 252     for (;;) {
 253         int p;
 254         q = line_pixel_length (t, q, ww);
 255         if (q > size)
 256             break;
 257         if (t[q] == '\n')
 258             break;
 259         p = word_start (t, q, size);
 260         if (p == -1)
 261             q = next_word_start (t, q, size);   /* Return the end of the word if the beginning
 262                                                    of the word is at the beginning of a line
 263                                                    (i.e. a very long word) */
 264         else
 265             q = p;
 266         if (q == -1)    /* end of paragraph */
 267             break;
 268         if (q)
 269             t[q - 1] = '\n';
 270     }
 271 }
 272
 273 static void replace_at (WEdit * edit, long q, int c)
 274 {
 275     edit_cursor_move (edit, q - edit->curs1);
 276     edit_delete (edit);
 277     edit_insert_ahead (edit, c);
 278 }
 279
 280 /* replaces a block of text */
 281 static void
 282 put_paragraph (WEdit * edit, unsigned char *t, long p, int indent, int size)
 283 {
 284     long cursor;
 285     int i, c = 0;
 286     cursor = edit->curs1;
 287     if (indent)
 288         while (strchr ("\t ", edit_get_byte (edit, p)))
 289             p++;
 290     for (i = 0; i < size; i++, p++) {
 291         if (i && indent) {
 292             if (t[i - 1] == '\n' && c == '\n') {
 293                 while (strchr ("\t ", edit_get_byte (edit, p)))
 294                     p++;
 295             } else if (t[i - 1] == '\n') {
 296                 long curs;
 297                 edit_cursor_move (edit, p - edit->curs1);
 298                 curs = edit->curs1;
 299                 edit_insert_indent (edit, indent);
 300                 if (cursor >= curs)
 301                     cursor += edit->curs1 - p;
 302                 p = edit->curs1;
 303             } else if (c == '\n') {
 304                 edit_cursor_move (edit, p - edit->curs1);
 305                 while (strchr ("\t ", edit_get_byte (edit, p))) {
 306                     edit_delete (edit);
 307                     if (cursor > edit->curs1)
 308                         cursor--;
 309                 }
 310                 p = edit->curs1;
 311             }
 312         }
 313         c = edit_get_byte (edit, p);
 314         if (c != t[i])
 315             replace_at (edit, p, t[i]);
 316     }
 317     edit_cursor_move (edit, cursor - edit->curs1);      /* restore cursor position */
 318 }
 319
 320 static int test_indent (WEdit * edit, long p, long q)
 321 {
 322     int indent;
 323     indent = edit_indent_width (edit, p++);
 324     if (!indent)
 325         return 0;
 326     for (; p < q; p++)
 327         if (edit_get_byte (edit, p - 1) == '\n')
 328             if (indent != edit_indent_width (edit, p))
 329                 return 0;
 330     return indent;
 331 }
 332
 333 void
 334 format_paragraph (WEdit *edit, int force)
 335 {
 336     long p, q;
 337     int size;
 338     unsigned char *t;
 339     int indent = 0;
 340     if (option_word_wrap_line_length < 2)
 341         return;
 342     if (line_is_blank (edit, edit->curs_line))
 343         return;
 344     p = begin_paragraph (edit, force);
 345     q = end_paragraph (edit, force);
 346     indent = test_indent (edit, p, q);
 347     t = get_paragraph (edit, p, q, indent, &size);
 348     if (!t)
 349         return;
 350     if (!force) {
 351         int i;
 352         if (strchr (NO_FORMAT_CHARS_START, *t)) {
 353             mhl_mem_free (t);
 354             return;
 355         }
 356         for (i = 0; i < size - 1; i++) {
 357             if (t[i] == '\n') {
 358                 if (strchr (NO_FORMAT_CHARS_START "\t ", t[i + 1])) {
 359                     mhl_mem_free (t);
 360                     return;
 361                 }
 362             }
 363         }
 364     }
 365     format_this (t, q - p, indent);
 366     put_paragraph (edit, t, p, indent, size);
 367     mhl_mem_free (t);
 368
 369     /* Scroll left as much as possible to show the formatted paragraph */
 370     edit_scroll_left (edit, -edit->start_col);
 371 }