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textbox.c

/*
 *  textbox.c -- implements the text box
 *
 *  ORIGINAL AUTHOR: Savio Lam (lam836@cs.cuhk.hk)
 *  MODIFIED FOR LINUX KERNEL CONFIG BY: William Roadcap (roadcap@cfw.com)
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version 2
 *  of the License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "dialog.h"

static void back_lines(int n);
static void print_page(WINDOW * win, int height, int width);
static void print_line(WINDOW * win, int row, int width);
static char *get_line(void);
static void print_position(WINDOW * win);

static int hscroll;
static int begin_reached, end_reached, page_length;
static const char *buf;
static const char *page;

/*
 * refresh window content
 */
static void refresh_text_box(WINDOW *dialog, WINDOW *box, int boxh, int boxw,
                                            int cur_y, int cur_x)
{
      print_page(box, boxh, boxw);
      print_position(dialog);
      wmove(dialog, cur_y, cur_x);  /* Restore cursor position */
      wrefresh(dialog);
}


/*
 * Display text from a file in a dialog box.
 */
int dialog_textbox(const char *title, const char *tbuf,
               int initial_height, int initial_width)
{
      int i, x, y, cur_x, cur_y, key = 0;
      int height, width, boxh, boxw;
      int passed_end;
      WINDOW *dialog, *box;

      begin_reached = 1;
      end_reached = 0;
      page_length = 0;
      hscroll = 0;
      buf = tbuf;
      page = buf; /* page is pointer to start of page to be displayed */

do_resize:
      getmaxyx(stdscr, height, width);
      if (height < 8 || width < 8)
            return -ERRDISPLAYTOOSMALL;
      if (initial_height != 0)
            height = initial_height;
      else
            if (height > 4)
                  height -= 4;
            else
                  height = 0;
      if (initial_width != 0)
            width = initial_width;
      else
            if (width > 5)
                  width -= 5;
            else
                  width = 0;

      /* center dialog box on screen */
      x = (COLS - width) / 2;
      y = (LINES - height) / 2;

      draw_shadow(stdscr, y, x, height, width);

      dialog = newwin(height, width, y, x);
      keypad(dialog, TRUE);

      /* Create window for box region, used for scrolling text */
      boxh = height - 4;
      boxw = width - 2;
      box = subwin(dialog, boxh, boxw, y + 1, x + 1);
      wattrset(box, dlg.dialog.atr);
      wbkgdset(box, dlg.dialog.atr & A_COLOR);

      keypad(box, TRUE);

      /* register the new window, along with its borders */
      draw_box(dialog, 0, 0, height, width,
             dlg.dialog.atr, dlg.border.atr);

      wattrset(dialog, dlg.border.atr);
      mvwaddch(dialog, height - 3, 0, ACS_LTEE);
      for (i = 0; i < width - 2; i++)
            waddch(dialog, ACS_HLINE);
      wattrset(dialog, dlg.dialog.atr);
      wbkgdset(dialog, dlg.dialog.atr & A_COLOR);
      waddch(dialog, ACS_RTEE);

      print_title(dialog, title, width);

      print_button(dialog, gettext(" Exit "), height - 2, width / 2 - 4, TRUE);
      wnoutrefresh(dialog);
      getyx(dialog, cur_y, cur_x);  /* Save cursor position */

      /* Print first page of text */
      attr_clear(box, boxh, boxw, dlg.dialog.atr);
      refresh_text_box(dialog, box, boxh, boxw, cur_y, cur_x);

      while ((key != KEY_ESC) && (key != '\n')) {
            key = wgetch(dialog);
            switch (key) {
            case 'E':   /* Exit */
            case 'e':
            case 'X':
            case 'x':
                  delwin(box);
                  delwin(dialog);
                  return 0;
            case 'g':   /* First page */
            case KEY_HOME:
                  if (!begin_reached) {
                        begin_reached = 1;
                        page = buf;
                        refresh_text_box(dialog, box, boxh, boxw,
                                     cur_y, cur_x);
                  }
                  break;
            case 'G':   /* Last page */
            case KEY_END:

                  end_reached = 1;
                  /* point to last char in buf */
                  page = buf + strlen(buf);
                  back_lines(boxh);
                  refresh_text_box(dialog, box, boxh, boxw,
                               cur_y, cur_x);
                  break;
            case 'K':   /* Previous line */
            case 'k':
            case KEY_UP:
                  if (!begin_reached) {
                        back_lines(page_length + 1);

                        /* We don't call print_page() here but use
                         * scrolling to ensure faster screen update.
                         * However, 'end_reached' and 'page_length'
                         * should still be updated, and 'page' should
                         * point to start of next page. This is done
                         * by calling get_line() in the following
                         * 'for' loop. */
                        scrollok(box, TRUE);
                        wscrl(box, -1);   /* Scroll box region down one line */
                        scrollok(box, FALSE);
                        page_length = 0;
                        passed_end = 0;
                        for (i = 0; i < boxh; i++) {
                              if (!i) {
                                    /* print first line of page */
                                    print_line(box, 0, boxw);
                                    wnoutrefresh(box);
                              } else
                                    /* Called to update 'end_reached' and 'page' */
                                    get_line();
                              if (!passed_end)
                                    page_length++;
                              if (end_reached && !passed_end)
                                    passed_end = 1;
                        }

                        print_position(dialog);
                        wmove(dialog, cur_y, cur_x);  /* Restore cursor position */
                        wrefresh(dialog);
                  }
                  break;
            case 'B':   /* Previous page */
            case 'b':
            case KEY_PPAGE:
                  if (begin_reached)
                        break;
                  back_lines(page_length + boxh);
                  refresh_text_box(dialog, box, boxh, boxw,
                               cur_y, cur_x);
                  break;
            case 'J':   /* Next line */
            case 'j':
            case KEY_DOWN:
                  if (!end_reached) {
                        begin_reached = 0;
                        scrollok(box, TRUE);
                        scroll(box);      /* Scroll box region up one line */
                        scrollok(box, FALSE);
                        print_line(box, boxh - 1, boxw);
                        wnoutrefresh(box);
                        print_position(dialog);
                        wmove(dialog, cur_y, cur_x);  /* Restore cursor position */
                        wrefresh(dialog);
                  }
                  break;
            case KEY_NPAGE:   /* Next page */
            case ' ':
                  if (end_reached)
                        break;

                  begin_reached = 0;
                  refresh_text_box(dialog, box, boxh, boxw,
                               cur_y, cur_x);
                  break;
            case '0':   /* Beginning of line */
            case 'H':   /* Scroll left */
            case 'h':
            case KEY_LEFT:
                  if (hscroll <= 0)
                        break;

                  if (key == '0')
                        hscroll = 0;
                  else
                        hscroll--;
                  /* Reprint current page to scroll horizontally */
                  back_lines(page_length);
                  refresh_text_box(dialog, box, boxh, boxw,
                               cur_y, cur_x);
                  break;
            case 'L':   /* Scroll right */
            case 'l':
            case KEY_RIGHT:
                  if (hscroll >= MAX_LEN)
                        break;
                  hscroll++;
                  /* Reprint current page to scroll horizontally */
                  back_lines(page_length);
                  refresh_text_box(dialog, box, boxh, boxw,
                               cur_y, cur_x);
                  break;
            case KEY_ESC:
                  key = on_key_esc(dialog);
                  break;
            case KEY_RESIZE:
                  back_lines(height);
                  delwin(box);
                  delwin(dialog);
                  on_key_resize();
                  goto do_resize;
            }
      }
      delwin(box);
      delwin(dialog);
      return key;       /* ESC pressed */
}

/*
 * Go back 'n' lines in text. Called by dialog_textbox().
 * 'page' will be updated to point to the desired line in 'buf'.
 */
static void back_lines(int n)
{
      int i;

      begin_reached = 0;
      /* Go back 'n' lines */
      for (i = 0; i < n; i++) {
            if (*page == '\0') {
                  if (end_reached) {
                        end_reached = 0;
                        continue;
                  }
            }
            if (page == buf) {
                  begin_reached = 1;
                  return;
            }
            page--;
            do {
                  if (page == buf) {
                        begin_reached = 1;
                        return;
                  }
                  page--;
            } while (*page != '\n');
            page++;
      }
}

/*
 * Print a new page of text. Called by dialog_textbox().
 */
static void print_page(WINDOW * win, int height, int width)
{
      int i, passed_end = 0;

      page_length = 0;
      for (i = 0; i < height; i++) {
            print_line(win, i, width);
            if (!passed_end)
                  page_length++;
            if (end_reached && !passed_end)
                  passed_end = 1;
      }
      wnoutrefresh(win);
}

/*
 * Print a new line of text. Called by dialog_textbox() and print_page().
 */
static void print_line(WINDOW * win, int row, int width)
{
      int y, x;
      char *line;

      line = get_line();
      line += MIN(strlen(line), hscroll); /* Scroll horizontally */
      wmove(win, row, 0);     /* move cursor to correct line */
      waddch(win, ' ');
      waddnstr(win, line, MIN(strlen(line), width - 2));

      getyx(win, y, x);
      /* Clear 'residue' of previous line */
#if OLD_NCURSES
      {
            int i;
            for (i = 0; i < width - x; i++)
                  waddch(win, ' ');
      }
#else
      wclrtoeol(win);
#endif
}

/*
 * Return current line of text. Called by dialog_textbox() and print_line().
 * 'page' should point to start of current line before calling, and will be
 * updated to point to start of next line.
 */
static char *get_line(void)
{
      int i = 0;
      static char line[MAX_LEN + 1];

      end_reached = 0;
      while (*page != '\n') {
            if (*page == '\0') {
                  if (!end_reached) {
                        end_reached = 1;
                        break;
                  }
            } else if (i < MAX_LEN)
                  line[i++] = *(page++);
            else {
                  /* Truncate lines longer than MAX_LEN characters */
                  if (i == MAX_LEN)
                        line[i++] = '\0';
                  page++;
            }
      }
      if (i <= MAX_LEN)
            line[i] = '\0';
      if (!end_reached)
            page++;           /* move pass '\n' */

      return line;
}

/*
 * Print current position
 */
static void print_position(WINDOW * win)
{
      int percent;

      wattrset(win, dlg.position_indicator.atr);
      wbkgdset(win, dlg.position_indicator.atr & A_COLOR);
      percent = (page - buf) * 100 / strlen(buf);
      wmove(win, getmaxy(win) - 3, getmaxx(win) - 9);
      wprintw(win, "(%3d%%)", percent);
}

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