scripts/kconfig/lxdialog/textbox.c - nest-hello/busybox - Git at Google

 /*
  *  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, int height, int width);

 static int hscroll, fd, file_size, bytes_read;
 static int begin_reached = 1, end_reached, page_length;
 static char *buf, *page;

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

 	/* Open input file for reading */
 	if ((fd = open(file, O_RDONLY)) == -1) {
 		endwin();
 		fprintf(stderr, "\nCan't open input file in dialog_textbox().\n");
 		exit(-1);
 	}
 	/* Get file size. Actually, 'file_size' is the real file size - 1,
 	   since it's only the last byte offset from the beginning */
 	if ((file_size = lseek(fd, 0, SEEK_END)) == -1) {
 		endwin();
 		fprintf(stderr, "\nError getting file size in dialog_textbox().\n");
 		exit(-1);
 	}
 	/* Restore file pointer to beginning of file after getting file size */
 	if (lseek(fd, 0, SEEK_SET) == -1) {
 		endwin();
 		fprintf(stderr, "\nError moving file pointer in dialog_textbox().\n");
 		exit(-1);
 	}
 	/* Allocate space for read buffer */
 	if ((buf = malloc(BUF_SIZE + 1)) == NULL) {
 		endwin();
 		fprintf(stderr, "\nCan't allocate memory in dialog_textbox().\n");
 		exit(-1);
 	}
 	if ((bytes_read = read(fd, buf, BUF_SIZE)) == -1) {
 		endwin();
 		fprintf(stderr, "\nError reading file in dialog_textbox().\n");
 		exit(-1);
 	}
 	buf[bytes_read] = '\0';	/* mark end of valid data */
 	page = buf;		/* page is pointer to start of page to be displayed */

 	/* 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 text region, used for scrolling text */
 	text = subwin(dialog, height - 4, width - 2, y + 1, x + 1);
 	wattrset(text, dialog_attr);
 	wbkgdset(text, dialog_attr & A_COLOR);

 	keypad(text, TRUE);

 	/* register the new window, along with its borders */
 	draw_box(dialog, 0, 0, height, width, dialog_attr, border_attr);

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

 	print_title(dialog, title, width);

 	print_button(dialog, " 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(text, height - 4, width - 2, dialog_attr);
 	print_page(text, height - 4, width - 2);
 	print_position(dialog, height, width);
 	wmove(dialog, cur_y, cur_x);	/* Restore cursor position */
 	wrefresh(dialog);

 	while ((key != ESC) && (key != '\n')) {
 		key = wgetch(dialog);
 		switch (key) {
 		case 'E':	/* Exit */
 		case 'e':
 		case 'X':
 		case 'x':
 			delwin(dialog);
 			free(buf);
 			close(fd);
 			return 0;
 		case 'g':	/* First page */
 		case KEY_HOME:
 			if (!begin_reached) {
 				begin_reached = 1;
 				/* First page not in buffer? */
 				if ((fpos = lseek(fd, 0, SEEK_CUR)) == -1) {
 					endwin();
 					fprintf(stderr, "\nError moving file pointer in dialog_textbox().\n");
 					exit(-1);
 				}
 				if (fpos > bytes_read) {	/* Yes, we have to read it in */
 					if (lseek(fd, 0, SEEK_SET) == -1) {
 						endwin();
 						fprintf(stderr, "\nError moving file pointer in "
 							        "dialog_textbox().\n");
 						exit(-1);
 					}
 					if ((bytes_read =
 					     read(fd, buf, BUF_SIZE)) == -1) {
 						endwin();
 						fprintf(stderr, "\nError reading file in dialog_textbox().\n");
 						exit(-1);
 					}
 					buf[bytes_read] = '\0';
 				}
 				page = buf;
 				print_page(text, height - 4, width - 2);
 				print_position(dialog, height, width);
 				wmove(dialog, cur_y, cur_x);	/* Restore cursor position */
 				wrefresh(dialog);
 			}
 			break;
 		case 'G':	/* Last page */
 		case KEY_END:

 			end_reached = 1;
 			/* Last page not in buffer? */
 			if ((fpos = lseek(fd, 0, SEEK_CUR)) == -1) {
 				endwin();
 				fprintf(stderr, "\nError moving file pointer in dialog_textbox().\n");
 				exit(-1);
 			}
 			if (fpos < file_size) {	/* Yes, we have to read it in */
 				if (lseek(fd, -BUF_SIZE, SEEK_END) == -1) {
 					endwin();
 					fprintf(stderr, "\nError moving file pointer in dialog_textbox().\n");
 					exit(-1);
 				}
 				if ((bytes_read =
 				     read(fd, buf, BUF_SIZE)) == -1) {
 					endwin();
 					fprintf(stderr, "\nError reading file in dialog_textbox().\n");
 					exit(-1);
 				}
 				buf[bytes_read] = '\0';
 			}
 			page = buf + bytes_read;
 			back_lines(height - 4);
 			print_page(text, height - 4, width - 2);
 			print_position(dialog, height, width);
 			wmove(dialog, cur_y, cur_x);	/* Restore cursor position */
 			wrefresh(dialog);
 			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(text, TRUE);
 				wscrl(text, -1);	/* Scroll text region down one line */
 				scrollok(text, FALSE);
 				page_length = 0;
 				passed_end = 0;
 				for (i = 0; i < height - 4; i++) {
 					if (!i) {
 						/* print first line of page */
 						print_line(text, 0, width - 2);
 						wnoutrefresh(text);
 					} 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, height, width);
 				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 + height - 4);
 			print_page(text, height - 4, width - 2);
 			print_position(dialog, height, width);
 			wmove(dialog, cur_y, cur_x);
 			wrefresh(dialog);
 			break;
 		case 'J':	/* Next line */
 		case 'j':
 		case KEY_DOWN:
 			if (!end_reached) {
 				begin_reached = 0;
 				scrollok(text, TRUE);
 				scroll(text);	/* Scroll text region up one line */
 				scrollok(text, FALSE);
 				print_line(text, height - 5, width - 2);
 				wnoutrefresh(text);
 				print_position(dialog, height, width);
 				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;
 			print_page(text, height - 4, width - 2);
 			print_position(dialog, height, width);
 			wmove(dialog, cur_y, cur_x);
 			wrefresh(dialog);
 			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);
 			print_page(text, height - 4, width - 2);
 			wmove(dialog, cur_y, cur_x);
 			wrefresh(dialog);
 			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);
 			print_page(text, height - 4, width - 2);
 			wmove(dialog, cur_y, cur_x);
 			wrefresh(dialog);
 			break;
 		case ESC:
 			break;
 		}
 	}

 	delwin(dialog);
 	free(buf);
 	close(fd);
 	return -1;		/* ESC pressed */
 }

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

 	begin_reached = 0;
 	/* We have to distinguish between end_reached and !end_reached
 	   since at end of file, the line is not ended by a '\n'.
 	   The code inside 'if' basically does a '--page' to move one
 	   character backward so as to skip '\n' of the previous line */
 	if (!end_reached) {
 		/* Either beginning of buffer or beginning of file reached? */
 		if (page == buf) {
 			if ((fpos = lseek(fd, 0, SEEK_CUR)) == -1) {
 				endwin();
 				fprintf(stderr, "\nError moving file pointer in "
 					        "back_lines().\n");
 				exit(-1);
 			}
 			if (fpos > bytes_read) {	/* Not beginning of file yet */
 				/* We've reached beginning of buffer, but not beginning of
 				   file yet, so read previous part of file into buffer.
 				   Note that we only move backward for BUF_SIZE/2 bytes,
 				   but not BUF_SIZE bytes to avoid re-reading again in
 				   print_page() later */
 				/* Really possible to move backward BUF_SIZE/2 bytes? */
 				if (fpos < BUF_SIZE / 2 + bytes_read) {
 					/* No, move less then */
 					if (lseek(fd, 0, SEEK_SET) == -1) {
 						endwin();
 						fprintf(stderr, "\nError moving file pointer in "
 						                "back_lines().\n");
 						exit(-1);
 					}
 					page = buf + fpos - bytes_read;
 				} else {	/* Move backward BUF_SIZE/2 bytes */
 					if (lseek (fd, -(BUF_SIZE / 2 + bytes_read), SEEK_CUR) == -1) {
 						endwin();
 						fprintf(stderr, "\nError moving file pointer "
 						                "in back_lines().\n");
 						exit(-1);
 					}
 					page = buf + BUF_SIZE / 2;
 				}
 				if ((bytes_read =
 				     read(fd, buf, BUF_SIZE)) == -1) {
 					endwin();
 					fprintf(stderr, "\nError reading file in back_lines().\n");
 					exit(-1);
 				}
 				buf[bytes_read] = '\0';
 			} else {	/* Beginning of file reached */
 				begin_reached = 1;
 				return;
 			}
 		}
 		if (*(--page) != '\n') {	/* '--page' here */
 			/* Something's wrong... */
 			endwin();
 			fprintf(stderr, "\nInternal error in back_lines().\n");
 			exit(-1);
 		}
 	}
 	/* Go back 'n' lines */
 	for (i = 0; i < n; i++)
 		do {
 			if (page == buf) {
 				if ((fpos = lseek(fd, 0, SEEK_CUR)) == -1) {
 					endwin();
 					fprintf(stderr, "\nError moving file pointer in back_lines().\n");
 					exit(-1);
 				}
 				if (fpos > bytes_read) {
 					/* Really possible to move backward BUF_SIZE/2 bytes? */
 					if (fpos < BUF_SIZE / 2 + bytes_read) {
 						/* No, move less then */
 						if (lseek(fd, 0, SEEK_SET) == -1) {
 							endwin();
 							fprintf(stderr, "\nError moving file pointer "
 							                "in back_lines().\n");
 							exit(-1);
 						}
 						page = buf + fpos - bytes_read;
 					} else {	/* Move backward BUF_SIZE/2 bytes */
 						if (lseek (fd, -(BUF_SIZE / 2 + bytes_read), SEEK_CUR) == -1) {
 							endwin();
 							fprintf(stderr, "\nError moving file pointer"
 							                " in back_lines().\n");
 							exit(-1);
 						}
 						page = buf + BUF_SIZE / 2;
 					}
 					if ((bytes_read =
 					     read(fd, buf, BUF_SIZE)) == -1) {
 						endwin();
 						fprintf(stderr, "\nError reading file in "
 						                "back_lines().\n");
 						exit(-1);
 					}
 					buf[bytes_read] = '\0';
 				} else {	/* Beginning of file reached */
 					begin_reached = 1;
 					return;
 				}
 			}
 		} 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)
 {
 	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));

 	/* Clear 'residue' of previous line */
 #if OLD_NCURSES
 	{
 		int i;
 		int y, x;

 		getyx(win, y, x);
 		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, fpos;
 	static char line[MAX_LEN + 1];

 	end_reached = 0;
 	while (*page != '\n') {
 		if (*page == '\0') {
 			/* Either end of file or end of buffer reached */
 			if ((fpos = lseek(fd, 0, SEEK_CUR)) == -1) {
 				endwin();
 				fprintf(stderr, "\nError moving file pointer in "
 				                "get_line().\n");
 				exit(-1);
 			}
 			if (fpos < file_size) {	/* Not end of file yet */
 				/* We've reached end of buffer, but not end of file yet,
 				   so read next part of file into buffer */
 				if ((bytes_read =
 				     read(fd, buf, BUF_SIZE)) == -1) {
 					endwin();
 					fprintf(stderr, "\nError reading file in get_line().\n");
 					exit(-1);
 				}
 				buf[bytes_read] = '\0';
 				page = buf;
 			} else {
 				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 height, int width)
 {
 	int fpos, percent;

 	if ((fpos = lseek(fd, 0, SEEK_CUR)) == -1) {
 		endwin();
 		fprintf(stderr, "\nError moving file pointer in print_position().\n");
 		exit(-1);
 	}
 	wattrset(win, position_indicator_attr);
 	wbkgdset(win, position_indicator_attr & A_COLOR);
 	percent = !file_size ?
 	    100 : ((fpos - bytes_read + page - buf) * 100) / file_size;
 	wmove(win, height - 3, width - 9);
 	wprintw(win, "(%3d%%)", percent);
 }
	/*
	* 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, int height, int width);

	static int hscroll, fd, file_size, bytes_read;
	static int begin_reached = 1, end_reached, page_length;
	static char buf, page;

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

	/* Open input file for reading */
	if ((fd = open(file, O_RDONLY)) == -1) {
	endwin();
	fprintf(stderr, "\nCan't open input file in dialog_textbox().\n");
	exit(-1);
	}
	/* Get file size. Actually, 'file_size' is the real file size - 1,
	since it's only the last byte offset from the beginning */
	if ((file_size = lseek(fd, 0, SEEK_END)) == -1) {
	endwin();
	fprintf(stderr, "\nError getting file size in dialog_textbox().\n");
	exit(-1);
	}
	/* Restore file pointer to beginning of file after getting file size */
	if (lseek(fd, 0, SEEK_SET) == -1) {
	endwin();
	fprintf(stderr, "\nError moving file pointer in dialog_textbox().\n");
	exit(-1);
	}
	/* Allocate space for read buffer */
	if ((buf = malloc(BUF_SIZE + 1)) == NULL) {
	endwin();
	fprintf(stderr, "\nCan't allocate memory in dialog_textbox().\n");
	exit(-1);
	}
	if ((bytes_read = read(fd, buf, BUF_SIZE)) == -1) {
	endwin();
	fprintf(stderr, "\nError reading file in dialog_textbox().\n");
	exit(-1);
	}
	buf[bytes_read] = '\0'; /* mark end of valid data */
	page = buf; /* page is pointer to start of page to be displayed */

	/* 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 text region, used for scrolling text */
	text = subwin(dialog, height - 4, width - 2, y + 1, x + 1);
	wattrset(text, dialog_attr);
	wbkgdset(text, dialog_attr & A_COLOR);

	keypad(text, TRUE);

	/* register the new window, along with its borders */
	draw_box(dialog, 0, 0, height, width, dialog_attr, border_attr);

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

	print_title(dialog, title, width);

	print_button(dialog, " 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(text, height - 4, width - 2, dialog_attr);
	print_page(text, height - 4, width - 2);
	print_position(dialog, height, width);
	wmove(dialog, cur_y, cur_x); /* Restore cursor position */
	wrefresh(dialog);

	while ((key != ESC) && (key != '\n')) {
	key = wgetch(dialog);
	switch (key) {
	case 'E': /* Exit */
	case 'e':
	case 'X':
	case 'x':
	delwin(dialog);
	free(buf);
	close(fd);
	return 0;
	case 'g': /* First page */
	case KEY_HOME:
	if (!begin_reached) {
	begin_reached = 1;
	/* First page not in buffer? */
	if ((fpos = lseek(fd, 0, SEEK_CUR)) == -1) {
	endwin();
	fprintf(stderr, "\nError moving file pointer in dialog_textbox().\n");
	exit(-1);
	}
	if (fpos > bytes_read) { /* Yes, we have to read it in */
	if (lseek(fd, 0, SEEK_SET) == -1) {
	endwin();
	fprintf(stderr, "\nError moving file pointer in "
	"dialog_textbox().\n");
	exit(-1);
	}
	if ((bytes_read =
	read(fd, buf, BUF_SIZE)) == -1) {
	endwin();
	fprintf(stderr, "\nError reading file in dialog_textbox().\n");
	exit(-1);
	}
	buf[bytes_read] = '\0';
	}
	page = buf;
	print_page(text, height - 4, width - 2);
	print_position(dialog, height, width);
	wmove(dialog, cur_y, cur_x); /* Restore cursor position */
	wrefresh(dialog);
	}
	break;
	case 'G': /* Last page */
	case KEY_END:

	end_reached = 1;
	/* Last page not in buffer? */
	if ((fpos = lseek(fd, 0, SEEK_CUR)) == -1) {
	endwin();
	fprintf(stderr, "\nError moving file pointer in dialog_textbox().\n");
	exit(-1);
	}
	if (fpos < file_size) { /* Yes, we have to read it in */
	if (lseek(fd, -BUF_SIZE, SEEK_END) == -1) {
	endwin();
	fprintf(stderr, "\nError moving file pointer in dialog_textbox().\n");
	exit(-1);
	}
	if ((bytes_read =
	read(fd, buf, BUF_SIZE)) == -1) {
	endwin();
	fprintf(stderr, "\nError reading file in dialog_textbox().\n");
	exit(-1);
	}
	buf[bytes_read] = '\0';
	}
	page = buf + bytes_read;
	back_lines(height - 4);
	print_page(text, height - 4, width - 2);
	print_position(dialog, height, width);
	wmove(dialog, cur_y, cur_x); /* Restore cursor position */
	wrefresh(dialog);
	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(text, TRUE);
	wscrl(text, -1); /* Scroll text region down one line */
	scrollok(text, FALSE);
	page_length = 0;
	passed_end = 0;
	for (i = 0; i < height - 4; i++) {
	if (!i) {
	/* print first line of page */
	print_line(text, 0, width - 2);
	wnoutrefresh(text);
	} 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, height, width);
	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 + height - 4);
	print_page(text, height - 4, width - 2);
	print_position(dialog, height, width);
	wmove(dialog, cur_y, cur_x);
	wrefresh(dialog);
	break;
	case 'J': /* Next line */
	case 'j':
	case KEY_DOWN:
	if (!end_reached) {
	begin_reached = 0;
	scrollok(text, TRUE);
	scroll(text); /* Scroll text region up one line */
	scrollok(text, FALSE);
	print_line(text, height - 5, width - 2);
	wnoutrefresh(text);
	print_position(dialog, height, width);
	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;
	print_page(text, height - 4, width - 2);
	print_position(dialog, height, width);
	wmove(dialog, cur_y, cur_x);
	wrefresh(dialog);
	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);
	print_page(text, height - 4, width - 2);
	wmove(dialog, cur_y, cur_x);
	wrefresh(dialog);
	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);
	print_page(text, height - 4, width - 2);
	wmove(dialog, cur_y, cur_x);
	wrefresh(dialog);
	break;
	case ESC:
	break;
	}
	}

	delwin(dialog);
	free(buf);
	close(fd);
	return -1; /* ESC pressed */
	}

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

	begin_reached = 0;
	/* We have to distinguish between end_reached and !end_reached
	since at end of file, the line is not ended by a '\n'.
	The code inside 'if' basically does a '--page' to move one
	character backward so as to skip '\n' of the previous line */
	if (!end_reached) {
	/* Either beginning of buffer or beginning of file reached? */
	if (page == buf) {
	if ((fpos = lseek(fd, 0, SEEK_CUR)) == -1) {
	endwin();
	fprintf(stderr, "\nError moving file pointer in "
	"back_lines().\n");
	exit(-1);
	}
	if (fpos > bytes_read) { /* Not beginning of file yet */
	/* We've reached beginning of buffer, but not beginning of
	file yet, so read previous part of file into buffer.
	Note that we only move backward for BUF_SIZE/2 bytes,
	but not BUF_SIZE bytes to avoid re-reading again in
	print_page() later */
	/* Really possible to move backward BUF_SIZE/2 bytes? */
	if (fpos < BUF_SIZE / 2 + bytes_read) {
	/* No, move less then */
	if (lseek(fd, 0, SEEK_SET) == -1) {
	endwin();
	fprintf(stderr, "\nError moving file pointer in "
	"back_lines().\n");
	exit(-1);
	}
	page = buf + fpos - bytes_read;
	} else { /* Move backward BUF_SIZE/2 bytes */
	if (lseek (fd, -(BUF_SIZE / 2 + bytes_read), SEEK_CUR) == -1) {
	endwin();
	fprintf(stderr, "\nError moving file pointer "
	"in back_lines().\n");
	exit(-1);
	}
	page = buf + BUF_SIZE / 2;
	}
	if ((bytes_read =
	read(fd, buf, BUF_SIZE)) == -1) {
	endwin();
	fprintf(stderr, "\nError reading file in back_lines().\n");
	exit(-1);
	}
	buf[bytes_read] = '\0';
	} else { /* Beginning of file reached */
	begin_reached = 1;
	return;
	}
	}
	if ((--page) != '\n') { / '--page' here */
	/* Something's wrong... */
	endwin();
	fprintf(stderr, "\nInternal error in back_lines().\n");
	exit(-1);
	}
	}
	/* Go back 'n' lines */
	for (i = 0; i < n; i++)
	do {
	if (page == buf) {
	if ((fpos = lseek(fd, 0, SEEK_CUR)) == -1) {
	endwin();
	fprintf(stderr, "\nError moving file pointer in back_lines().\n");
	exit(-1);
	}
	if (fpos > bytes_read) {
	/* Really possible to move backward BUF_SIZE/2 bytes? */
	if (fpos < BUF_SIZE / 2 + bytes_read) {
	/* No, move less then */
	if (lseek(fd, 0, SEEK_SET) == -1) {
	endwin();
	fprintf(stderr, "\nError moving file pointer "
	"in back_lines().\n");
	exit(-1);
	}
	page = buf + fpos - bytes_read;
	} else { /* Move backward BUF_SIZE/2 bytes */
	if (lseek (fd, -(BUF_SIZE / 2 + bytes_read), SEEK_CUR) == -1) {
	endwin();
	fprintf(stderr, "\nError moving file pointer"
	" in back_lines().\n");
	exit(-1);
	}
	page = buf + BUF_SIZE / 2;
	}
	if ((bytes_read =
	read(fd, buf, BUF_SIZE)) == -1) {
	endwin();
	fprintf(stderr, "\nError reading file in "
	"back_lines().\n");
	exit(-1);
	}
	buf[bytes_read] = '\0';
	} else { /* Beginning of file reached */
	begin_reached = 1;
	return;
	}
	}
	} 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)
	{
	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));

	/* Clear 'residue' of previous line */
	#if OLD_NCURSES
	{
	int i;
	int y, x;

	getyx(win, y, x);
	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, fpos;
	static char line[MAX_LEN + 1];

	end_reached = 0;
	while (*page != '\n') {
	if (*page == '\0') {
	/* Either end of file or end of buffer reached */
	if ((fpos = lseek(fd, 0, SEEK_CUR)) == -1) {
	endwin();
	fprintf(stderr, "\nError moving file pointer in "
	"get_line().\n");
	exit(-1);
	}
	if (fpos < file_size) { /* Not end of file yet */
	/* We've reached end of buffer, but not end of file yet,
	so read next part of file into buffer */
	if ((bytes_read =
	read(fd, buf, BUF_SIZE)) == -1) {
	endwin();
	fprintf(stderr, "\nError reading file in get_line().\n");
	exit(-1);
	}
	buf[bytes_read] = '\0';
	page = buf;
	} else {
	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 height, int width)
	{
	int fpos, percent;

	if ((fpos = lseek(fd, 0, SEEK_CUR)) == -1) {
	endwin();
	fprintf(stderr, "\nError moving file pointer in print_position().\n");
	exit(-1);
	}
	wattrset(win, position_indicator_attr);
	wbkgdset(win, position_indicator_attr & A_COLOR);
	percent = !file_size ?
	100 : ((fpos - bytes_read + page - buf) * 100) / file_size;
	wmove(win, height - 3, width - 9);
	wprintw(win, "(%3d%%)", percent);
	}