scripts/lxdialog/textbox.c

/* */
This source file includes following definitions.
dialog_textbox
back_lines
print_page
print_line
get_line
print_position
   1 /*
   2  *  textbox.c -- implements the text box
   3  *
   4  *  ORIGINAL AUTHOR: Savio Lam (lam836@cs.cuhk.hk)
   5  *  MODIFIED FOR LINUX KERNEL CONFIG BY: William Roadcap (roadcap@cfw.com)
   6  *
   7  *  This program is free software; you can redistribute it and/or
   8  *  modify it under the terms of the GNU General Public License
   9  *  as published by the Free Software Foundation; either version 2
  10  *  of the License, or (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, write to the Free Software
  19  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21 
  22 #include "dialog.h"
  23 
  24 static void back_lines (int n);
  25 static void print_page (WINDOW * win, int height, int width);
  26 static void print_line (WINDOW * win, int row, int width);
  27 static char *get_line (void);
  28 static void print_position (WINDOW * win, int height, int width);
  29 
  30 static int hscroll = 0, fd, file_size, bytes_read;
  31 static int begin_reached = 1, end_reached = 0, page_length;
  32 static char *buf, *page;
  33 
  34 /*
  35  * Display text from a file in a dialog box.
  36  */
  37 int
  38 dialog_textbox (const char *title, const char *file, int height, int width)
     /*  */
  39 {
  40     int i, x, y, cur_x, cur_y, fpos, key = 0;
  41     int passed_end;
  42     char search_term[MAX_LEN + 1];
  43     WINDOW *dialog, *text;
  44 
  45     search_term[0] = '\0';      /* no search term entered yet */
  46 
  47     /* Open input file for reading */
  48     if ((fd = open (file, O_RDONLY)) == -1) {
  49         endwin ();
  50         fprintf (stderr,
  51                  "\nCan't open input file in dialog_textbox().\n");
  52         exit (-1);
  53     }
  54     /* Get file size. Actually, 'file_size' is the real file size - 1,
  55        since it's only the last byte offset from the beginning */
  56     if ((file_size = lseek (fd, 0, SEEK_END)) == -1) {
  57         endwin ();
  58         fprintf (stderr, "\nError getting file size in dialog_textbox().\n");
  59         exit (-1);
  60     }
  61     /* Restore file pointer to beginning of file after getting file size */
  62     if (lseek (fd, 0, SEEK_SET) == -1) {
  63         endwin ();
  64         fprintf (stderr, "\nError moving file pointer in dialog_textbox().\n");
  65         exit (-1);
  66     }
  67     /* Allocate space for read buffer */
  68     if ((buf = malloc (BUF_SIZE + 1)) == NULL) {
  69         endwin ();
  70         fprintf (stderr, "\nCan't allocate memory in dialog_textbox().\n");
  71         exit (-1);
  72     }
  73     if ((bytes_read = read (fd, buf, BUF_SIZE)) == -1) {
  74         endwin ();
  75         fprintf (stderr, "\nError reading file in dialog_textbox().\n");
  76         exit (-1);
  77     }
  78     buf[bytes_read] = '\0';     /* mark end of valid data */
  79     page = buf;                 /* page is pointer to start of page to be displayed */
  80 
  81     /* center dialog box on screen */
  82     x = (COLS - width) / 2;
  83     y = (LINES - height) / 2;
  84 
  85 
  86     draw_shadow (stdscr, y, x, height, width);
  87 
  88     dialog = newwin (height, width, y, x);
  89     keypad (dialog, TRUE);
  90 
  91     /* Create window for text region, used for scrolling text */
  92     text = subwin (dialog, height - 4, width - 2, y + 1, x + 1);
  93 
  94     keypad (text, TRUE);
  95 
  96     /* register the new window, along with its borders */
  97     draw_box (dialog, 0, 0, height, width, dialog_attr, border_attr);
  98 
  99     wattrset (dialog, border_attr);
 100     mvwaddch (dialog, height-3, 0, ACS_LTEE);
 101     for (i = 0; i < width - 2; i++)
 102         waddch (dialog, ACS_HLINE);
 103     wattrset (dialog, dialog_attr);
 104     waddch (dialog, ACS_RTEE);
 105 
 106     if (title != NULL) {
 107         wattrset (dialog, title_attr);
 108         mvwaddch (dialog, 0, (width - strlen(title))/2 - 1, ' ');
 109         waddstr (dialog, (char *)title);
 110         waddch (dialog, ' ');
 111     }
 112     print_button (dialog, " Exit ", height - 2, width / 2 - 4, TRUE);
 113     wnoutrefresh (dialog);
 114     getyx (dialog, cur_y, cur_x);       /* Save cursor position */
 115 
 116     /* Print first page of text */
 117     attr_clear (text, height - 4, width - 2, dialog_attr);
 118     print_page (text, height - 4, width - 2);
 119     print_position (dialog, height, width);
 120     wmove (dialog, cur_y, cur_x);       /* Restore cursor position */
 121     wrefresh (dialog);
 122 
 123     while ((key != ESC) && (key != '\n')) {
 124         key = wgetch (dialog);
 125         switch (key) {
 126         case 'E':               /* Exit */
 127         case 'e':
 128         case 'X':
 129         case 'x':
 130             delwin (dialog);
 131             free (buf);
 132             close (fd);
 133             return 0;
 134         case 'g':               /* First page */
 135         case KEY_HOME:
 136             if (!begin_reached) {
 137                 begin_reached = 1;
 138                 /* First page not in buffer? */
 139                 if ((fpos = lseek (fd, 0, SEEK_CUR)) == -1) {
 140                     endwin ();
 141                     fprintf (stderr,
 142                       "\nError moving file pointer in dialog_textbox().\n");
 143                     exit (-1);
 144                 }
 145                 if (fpos > bytes_read) {        /* Yes, we have to read it in */
 146                     if (lseek (fd, 0, SEEK_SET) == -1) {
 147                         endwin ();
 148                         fprintf (stderr, "\nError moving file pointer in "
 149                                  "dialog_textbox().\n");
 150                         exit (-1);
 151                     }
 152                     if ((bytes_read = read (fd, buf, BUF_SIZE)) == -1) {
 153                         endwin ();
 154                         fprintf (stderr,
 155                              "\nError reading file in dialog_textbox().\n");
 156                         exit (-1);
 157                     }
 158                     buf[bytes_read] = '\0';
 159                 }
 160                 page = buf;
 161                 print_page (text, height - 4, width - 2);
 162                 print_position (dialog, height, width);
 163                 wmove (dialog, cur_y, cur_x);   /* Restore cursor position */
 164                 wrefresh (dialog);
 165             }
 166             break;
 167         case 'G':               /* Last page */
 168         case KEY_END:
 169 
 170             end_reached = 1;
 171             /* Last page not in buffer? */
 172             if ((fpos = lseek (fd, 0, SEEK_CUR)) == -1) {
 173                 endwin ();
 174                 fprintf (stderr,
 175                       "\nError moving file pointer in dialog_textbox().\n");
 176                 exit (-1);
 177             }
 178             if (fpos < file_size) {     /* Yes, we have to read it in */
 179                 if (lseek (fd, -BUF_SIZE, SEEK_END) == -1) {
 180                     endwin ();
 181                     fprintf (stderr,
 182                       "\nError moving file pointer in dialog_textbox().\n");
 183                     exit (-1);
 184                 }
 185                 if ((bytes_read = read (fd, buf, BUF_SIZE)) == -1) {
 186                     endwin ();
 187                     fprintf (stderr,
 188                              "\nError reading file in dialog_textbox().\n");
 189                     exit (-1);
 190                 }
 191                 buf[bytes_read] = '\0';
 192             }
 193             page = buf + bytes_read;
 194             back_lines (height - 4);
 195             print_page (text, height - 4, width - 2);
 196             print_position (dialog, height, width);
 197             wmove (dialog, cur_y, cur_x);       /* Restore cursor position */
 198             wrefresh (dialog);
 199             break;
 200         case 'K':               /* Previous line */
 201         case 'k':
 202         case KEY_UP:
 203             if (!begin_reached) {
 204                 back_lines (page_length + 1);
 205 
 206                 /* We don't call print_page() here but use scrolling to ensure
 207                    faster screen update. However, 'end_reached' and
 208                    'page_length' should still be updated, and 'page' should
 209                    point to start of next page. This is done by calling
 210                    get_line() in the following 'for' loop. */
 211                 scrollok (text, TRUE);
 212                 wscrl (text, -1);       /* Scroll text region down one line */
 213                 scrollok (text, FALSE);
 214                 page_length = 0;
 215                 passed_end = 0;
 216                 for (i = 0; i < height - 4; i++) {
 217                     if (!i) {
 218                         /* print first line of page */
 219                         print_line (text, 0, width - 2);
 220                         wnoutrefresh (text);
 221                     } else
 222                         /* Called to update 'end_reached' and 'page' */
 223                         get_line ();
 224                     if (!passed_end)
 225                         page_length++;
 226                     if (end_reached && !passed_end)
 227                         passed_end = 1;
 228                 }
 229 
 230                 print_position (dialog, height, width);
 231                 wmove (dialog, cur_y, cur_x);   /* Restore cursor position */
 232                 wrefresh (dialog);
 233             }
 234             break;
 235         case 'B':               /* Previous page */
 236         case 'b':
 237         case KEY_PPAGE:
 238             if (begin_reached)
 239                 break;
 240             back_lines (page_length + height - 4);
 241             print_page (text, height - 4, width - 2);
 242             print_position (dialog, height, width);
 243             wmove (dialog, cur_y, cur_x);
 244             wrefresh (dialog);
 245             break;
 246         case 'J':               /* Next line */
 247         case 'j':
 248         case KEY_DOWN:
 249             if (!end_reached) {
 250                 begin_reached = 0;
 251                 scrollok (text, TRUE);
 252                 scroll (text);  /* Scroll text region up one line */
 253                 scrollok (text, FALSE);
 254                 print_line (text, height - 5, width - 2);
 255                 wnoutrefresh (text);
 256                 print_position (dialog, height, width);
 257                 wmove (dialog, cur_y, cur_x);   /* Restore cursor position */
 258                 wrefresh (dialog);
 259             }
 260             break;
 261         case KEY_NPAGE:         /* Next page */
 262         case ' ':
 263             if (end_reached)
 264                 break;
 265 
 266             begin_reached = 0;
 267             print_page (text, height - 4, width - 2);
 268             print_position (dialog, height, width);
 269             wmove (dialog, cur_y, cur_x);
 270             wrefresh (dialog);
 271             break;
 272         case '0':               /* Beginning of line */
 273         case 'H':               /* Scroll left */
 274         case 'h':
 275         case KEY_LEFT:
 276             if (hscroll <= 0)
 277                 break;
 278 
 279             if (key == '0')
 280                 hscroll = 0;
 281             else
 282                 hscroll--;
 283             /* Reprint current page to scroll horizontally */
 284             back_lines (page_length);
 285             print_page (text, height - 4, width - 2);
 286             wmove (dialog, cur_y, cur_x);
 287             wrefresh (dialog);
 288             break;
 289         case 'L':               /* Scroll right */
 290         case 'l':
 291         case KEY_RIGHT:
 292             if (hscroll >= MAX_LEN)
 293                 break;
 294             hscroll++;
 295             /* Reprint current page to scroll horizontally */
 296             back_lines (page_length);
 297             print_page (text, height - 4, width - 2);
 298             wmove (dialog, cur_y, cur_x);
 299             wrefresh (dialog);
 300             break;
 301         case ESC:
 302             break;
 303         }
 304     }
 305 
 306     delwin (dialog);
 307     free (buf);
 308     close (fd);
 309     return -1;                  /* ESC pressed */
 310 }
 311 
 312 /*
 313  * Go back 'n' lines in text file. Called by dialog_textbox().
 314  * 'page' will be updated to point to the desired line in 'buf'.
 315  */
 316 static void
 317 back_lines (int n)
     /*  */
 318 {
 319     int i, fpos;
 320 
 321     begin_reached = 0;
 322     /* We have to distinguish between end_reached and !end_reached
 323        since at end of file, the line is not ended by a '\n'.
 324        The code inside 'if' basically does a '--page' to move one
 325        character backward so as to skip '\n' of the previous line */
 326     if (!end_reached) {
 327         /* Either beginning of buffer or beginning of file reached? */
 328         if (page == buf) {
 329             if ((fpos = lseek (fd, 0, SEEK_CUR)) == -1) {
 330                 endwin ();
 331                 fprintf (stderr, "\nError moving file pointer in "
 332                          "back_lines().\n");
 333                 exit (-1);
 334             }
 335             if (fpos > bytes_read) {    /* Not beginning of file yet */
 336                 /* We've reached beginning of buffer, but not beginning of
 337                    file yet, so read previous part of file into buffer.
 338                    Note that we only move backward for BUF_SIZE/2 bytes,
 339                    but not BUF_SIZE bytes to avoid re-reading again in
 340                    print_page() later */
 341                 /* Really possible to move backward BUF_SIZE/2 bytes? */
 342                 if (fpos < BUF_SIZE / 2 + bytes_read) {
 343                     /* No, move less then */
 344                     if (lseek (fd, 0, SEEK_SET) == -1) {
 345                         endwin ();
 346                         fprintf (stderr, "\nError moving file pointer in "
 347                                  "back_lines().\n");
 348                         exit (-1);
 349                     }
 350                     page = buf + fpos - bytes_read;
 351                 } else {        /* Move backward BUF_SIZE/2 bytes */
 352                     if (lseek (fd, -(BUF_SIZE / 2 + bytes_read), SEEK_CUR)
 353                         == -1) {
 354                         endwin ();
 355                         fprintf (stderr, "\nError moving file pointer "
 356                                  "in back_lines().\n");
 357                         exit (-1);
 358                     }
 359                     page = buf + BUF_SIZE / 2;
 360                 }
 361                 if ((bytes_read = read (fd, buf, BUF_SIZE)) == -1) {
 362                     endwin ();
 363                     fprintf (stderr, "\nError reading file in back_lines().\n");
 364                     exit (-1);
 365                 }
 366                 buf[bytes_read] = '\0';
 367             } else {            /* Beginning of file reached */
 368                 begin_reached = 1;
 369                 return;
 370             }
 371         }
 372         if (*(--page) != '\n') {        /* '--page' here */
 373             /* Something's wrong... */
 374             endwin ();
 375             fprintf (stderr, "\nInternal error in back_lines().\n");
 376             exit (-1);
 377         }
 378     }
 379     /* Go back 'n' lines */
 380     for (i = 0; i < n; i++)
 381         do {
 382             if (page == buf) {
 383                 if ((fpos = lseek (fd, 0, SEEK_CUR)) == -1) {
 384                     endwin ();
 385                     fprintf (stderr,
 386                           "\nError moving file pointer in back_lines().\n");
 387                     exit (-1);
 388                 }
 389                 if (fpos > bytes_read) {
 390                     /* Really possible to move backward BUF_SIZE/2 bytes? */
 391                     if (fpos < BUF_SIZE / 2 + bytes_read) {
 392                         /* No, move less then */
 393                         if (lseek (fd, 0, SEEK_SET) == -1) {
 394                             endwin ();
 395                             fprintf (stderr, "\nError moving file pointer "
 396                                      "in back_lines().\n");
 397                             exit (-1);
 398                         }
 399                         page = buf + fpos - bytes_read;
 400                     } else {    /* Move backward BUF_SIZE/2 bytes */
 401                         if (lseek (fd, -(BUF_SIZE / 2 + bytes_read),
 402                                    SEEK_CUR) == -1) {
 403                             endwin ();
 404                             fprintf (stderr, "\nError moving file pointer"
 405                                      " in back_lines().\n");
 406                             exit (-1);
 407                         }
 408                         page = buf + BUF_SIZE / 2;
 409                     }
 410                     if ((bytes_read = read (fd, buf, BUF_SIZE)) == -1) {
 411                         endwin ();
 412                         fprintf (stderr, "\nError reading file in "
 413                                  "back_lines().\n");
 414                         exit (-1);
 415                     }
 416                     buf[bytes_read] = '\0';
 417                 } else {        /* Beginning of file reached */
 418                     begin_reached = 1;
 419                     return;
 420                 }
 421             }
 422         } while (*(--page) != '\n');
 423     page++;
 424 }
 425 
 426 /*
 427  * Print a new page of text. Called by dialog_textbox().
 428  */
 429 static void
 430 print_page (WINDOW * win, int height, int width)
     /*  */
 431 {
 432     int i, passed_end = 0;
 433 
 434     page_length = 0;
 435     for (i = 0; i < height; i++) {
 436         print_line (win, i, width);
 437         if (!passed_end)
 438             page_length++;
 439         if (end_reached && !passed_end)
 440             passed_end = 1;
 441     }
 442     wnoutrefresh (win);
 443 }
 444 
 445 /*
 446  * Print a new line of text. Called by dialog_textbox() and print_page().
 447  */
 448 static void
 449 print_line (WINDOW * win, int row, int width)
     /*  */
 450 {
 451     int i, y, x;
 452     char *line;
 453 
 454     line = get_line ();
 455     line += MIN (strlen (line), hscroll);       /* Scroll horizontally */
 456     wmove (win, row, 0);        /* move cursor to correct line */
 457     waddch (win, ' ');
 458     waddnstr (win, line, MIN (strlen (line), width - 2));
 459 
 460     getyx (win, y, x);
 461     /* Clear 'residue' of previous line */
 462     for (i = 0; i < width - x; i++)
 463         waddch (win, ' ');
 464 }
 465 
 466 /*
 467  * Return current line of text. Called by dialog_textbox() and print_line().
 468  * 'page' should point to start of current line before calling, and will be
 469  * updated to point to start of next line.
 470  */
 471 static char *
 472 get_line (void)
     /*  */
 473 {
 474     int i = 0, fpos;
 475     static char line[MAX_LEN + 1];
 476 
 477     end_reached = 0;
 478     while (*page != '\n') {
 479         if (*page == '\0') {
 480             /* Either end of file or end of buffer reached */
 481             if ((fpos = lseek (fd, 0, SEEK_CUR)) == -1) {
 482                 endwin ();
 483                 fprintf (stderr, "\nError moving file pointer in "
 484                          "get_line().\n");
 485                 exit (-1);
 486             }
 487             if (fpos < file_size) {     /* Not end of file yet */
 488                 /* We've reached end of buffer, but not end of file yet,
 489                    so read next part of file into buffer */
 490                 if ((bytes_read = read (fd, buf, BUF_SIZE)) == -1) {
 491                     endwin ();
 492                     fprintf (stderr, "\nError reading file in get_line().\n");
 493                     exit (-1);
 494                 }
 495                 buf[bytes_read] = '\0';
 496                 page = buf;
 497             } else {
 498                 if (!end_reached)
 499                     end_reached = 1;
 500                 break;
 501             }
 502         } else if (i < MAX_LEN)
 503             line[i++] = *(page++);
 504         else {
 505             /* Truncate lines longer than MAX_LEN characters */
 506             if (i == MAX_LEN)
 507                 line[i++] = '\0';
 508             page++;
 509         }
 510     }
 511     if (i <= MAX_LEN)
 512         line[i] = '\0';
 513     if (!end_reached)
 514         page++;                 /* move pass '\n' */
 515 
 516     return line;
 517 }
 518 
 519 /*
 520  * Print current position
 521  */
 522 static void
 523 print_position (WINDOW * win, int height, int width)
     /*  */
 524 {
 525     int fpos, percent;
 526 
 527     if ((fpos = lseek (fd, 0, SEEK_CUR)) == -1) {
 528         endwin ();
 529         fprintf (stderr, "\nError moving file pointer in print_position().\n");
 530         exit (-1);
 531     }
 532     wattrset (win, position_indicator_attr);
 533     percent = !file_size ?
 534         100 : ((fpos - bytes_read + page - buf) * 100) / file_size;
 535     wmove (win, height - 3, width - 9);
 536     wprintw (win, "(%3d%%)", percent);
 537 }
/* */
root/scripts/lxdialog/textbox.c

DEFINITIONS
