[unix-history] / usr / src / usr.bin / more / screen.c

/*
 * Copyright (c) 1988 Mark Nudleman
 * Copyright (c) 1988 Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#ifndef lint
static char sccsid[] = "@(#)screen.c	5.7 (Berkeley) %G%";
#endif /* not lint */

/*
 * Routines which deal with the characteristics of the terminal.
 * Uses termcap to be as terminal-independent as possible.
 *
 * {{ Someday this should be rewritten to use curses. }}
 */

#include <stdio.h>
#include <less.h>

#if TERMIO
#include <termio.h>
#else
#include <sgtty.h>
#endif

#ifdef TIOCGWINSZ
#include <sys/ioctl.h>
#else
/*
 * For the Unix PC (ATT 7300 & 3B1):
 * Since WIOCGETD is defined in sys/window.h, we can't use that to decide
 * whether to include sys/window.h.  Use SIGPHONE from sys/signal.h instead.
 */
#include <sys/signal.h>
#ifdef SIGPHONE
#include <sys/window.h>
#endif
#endif

/*
 * Strings passed to tputs() to do various terminal functions.
 */
static char
	*sc_pad,		/* Pad string */
	*sc_home,		/* Cursor home */
	*sc_addline,		/* Add line, scroll down following lines */
	*sc_lower_left,		/* Cursor to last line, first column */
	*sc_move,		/* General cursor positioning */
	*sc_clear,		/* Clear screen */
	*sc_eol_clear,		/* Clear to end of line */
	*sc_s_in,		/* Enter standout (highlighted) mode */
	*sc_s_out,		/* Exit standout mode */
	*sc_u_in,		/* Enter underline mode */
	*sc_u_out,		/* Exit underline mode */
	*sc_b_in,		/* Enter bold mode */
	*sc_b_out,		/* Exit bold mode */
	*sc_backspace,		/* Backspace cursor */
	*sc_init,		/* Startup terminal initialization */
	*sc_deinit;		/* Exit terminal de-intialization */

int auto_wrap;			/* Terminal does \r\n when write past margin */
int ignaw;			/* Terminal ignores \n immediately after wrap */
				/* The user's erase and line-kill chars */
int erase_char, kill_char, werase_char;
int sc_width, sc_height = -1;	/* Height & width of screen */
int sc_window = -1;		/* window size for forward and backward */
int bo_width, be_width;		/* Printing width of boldface sequences */
int ul_width, ue_width;		/* Printing width of underline sequences */
int so_width, se_width;		/* Printing width of standout sequences */

/*
 * These two variables are sometimes defined in,
 * and needed by, the termcap library.
 * It may be necessary on some systems to declare them extern here.
 */
/*extern*/ short ospeed;	/* Terminal output baud rate */
/*extern*/ char PC;		/* Pad character */

extern int back_scroll;
char *tgetstr();
char *tgoto();

/*
 * Change terminal to "raw mode", or restore to "normal" mode.
 * "Raw mode" means 
 *	1. An outstanding read will complete on receipt of a single keystroke.
 *	2. Input is not echoed.  
 *	3. On output, \n is mapped to \r\n.
 *	4. \t is NOT expanded into spaces.
 *	5. Signal-causing characters such as ctrl-C (interrupt),
 *	   etc. are NOT disabled.
 * It doesn't matter whether an input \n is mapped to \r, or vice versa.
 */
raw_mode(on)
	int on;
{
#if TERMIO
	struct termio s;
	static struct termio save_term;

	if (on)
	{
		/*
		 * Get terminal modes.
		 */
		(void)ioctl(2, TCGETA, &s);

		/*
		 * Save modes and set certain variables dependent on modes.
		 */
		save_term = s;
		ospeed = s.c_cflag & CBAUD;
		erase_char = s.c_cc[VERASE];
		kill_char = s.c_cc[VKILL];
		werase_char = s.c_cc[VWERASE];

		/*
		 * Set the modes to the way we want them.
		 */
		s.c_lflag &= ~(ICANON|ECHO|ECHOE|ECHOK|ECHONL);
		s.c_oflag |=  (OPOST|ONLCR|TAB3);
		s.c_oflag &= ~(OCRNL|ONOCR|ONLRET);
		s.c_cc[VMIN] = 1;
		s.c_cc[VTIME] = 0;
	} else
	{
		/*
		 * Restore saved modes.
		 */
		s = save_term;
	}
	(void)ioctl(2, TCSETAW, &s);
#else
	struct sgttyb s;
	static struct sgttyb save_term;

	if (on)
	{
		/*
		 * Get terminal modes.
		 */
		(void)ioctl(2, TIOCGETP, &s);

		/*
		 * Save modes and set certain variables dependent on modes.
		 */
		save_term = s;
		ospeed = s.sg_ospeed;
		erase_char = s.sg_erase;
		kill_char = s.sg_kill;
		werase_char = -1;

		/*
		 * Set the modes to the way we want them.
		 */
		s.sg_flags |= CBREAK;
		s.sg_flags &= ~(ECHO|XTABS);
	} else
	{
		/*
		 * Restore saved modes.
		 */
		s = save_term;
	}
	(void)ioctl(2, TIOCSETN, &s);
#endif
}

/*
 * Get terminal capabilities via termcap.
 */
get_term()
{
	char termbuf[2048];
	char *sp;
	char *term;
	int hard;
#ifdef TIOCGWINSZ
	struct winsize w;
#else
#ifdef WIOCGETD
	struct uwdata w;
#endif
#endif
	static char sbuf[1024];

	char *getenv(), *strcpy();

	/*
	 * Find out what kind of terminal this is.
	 */
 	if ((term = getenv("TERM")) == NULL)
 		term = "unknown";
 	if (tgetent(termbuf, term) <= 0)
 		(void)strcpy(termbuf, "dumb:co#80:hc:");

	/*
	 * Get size of the screen.
	 */
#ifdef TIOCGWINSZ
	if (ioctl(2, TIOCGWINSZ, &w) == 0 && w.ws_row > 0)
		sc_height = w.ws_row;
#else
#ifdef WIOCGETD
	if (ioctl(2, WIOCGETD, &w) == 0 && w.uw_height > 0)
		sc_height = w.uw_height/w.uw_vs;
#endif
#endif
	else
		sc_height = tgetnum("li");
	hard = (sc_height < 0 || tgetflag("hc"));
	if (hard) {
		/* Oh no, this is a hardcopy terminal. */
		sc_height = 24;
	}

#ifdef TIOCGWINSZ
 	if (ioctl(2, TIOCGWINSZ, &w) == 0 && w.ws_col > 0)
		sc_width = w.ws_col;
	else
#ifdef WIOCGETD
	if (ioctl(2, WIOCGETD, &w) == 0 && w.uw_width > 0)
		sc_width = w.uw_width/w.uw_hs;
	else
#endif
#endif
 		sc_width = tgetnum("co");
 	if (sc_width < 0)
  		sc_width = 80;

	auto_wrap = tgetflag("am");
	ignaw = tgetflag("xn");

	/*
	 * Assumes termcap variable "sg" is the printing width of
	 * the standout sequence, the end standout sequence,
	 * the underline sequence, the end underline sequence,
	 * the boldface sequence, and the end boldface sequence.
	 */
	if ((so_width = tgetnum("sg")) < 0)
		so_width = 0;
	be_width = bo_width = ue_width = ul_width = se_width = so_width;

	/*
	 * Get various string-valued capabilities.
	 */
	sp = sbuf;

	sc_pad = tgetstr("pc", &sp);
	if (sc_pad != NULL)
		PC = *sc_pad;

	sc_init = tgetstr("ti", &sp);
	if (sc_init == NULL)
		sc_init = "";

	sc_deinit= tgetstr("te", &sp);
	if (sc_deinit == NULL)
		sc_deinit = "";

	sc_eol_clear = tgetstr("ce", &sp);
	if (hard || sc_eol_clear == NULL || *sc_eol_clear == '\0')
	{
		sc_eol_clear = "";
	}

	sc_clear = tgetstr("cl", &sp);
	if (hard || sc_clear == NULL || *sc_clear == '\0')
	{
		sc_clear = "\n\n";
	}

	sc_move = tgetstr("cm", &sp);
	if (hard || sc_move == NULL || *sc_move == '\0')
	{
		/*
		 * This is not an error here, because we don't 
		 * always need sc_move.
		 * We need it only if we don't have home or lower-left.
		 */
		sc_move = "";
	}

	sc_s_in = tgetstr("so", &sp);
	if (hard || sc_s_in == NULL)
		sc_s_in = "";

	sc_s_out = tgetstr("se", &sp);
	if (hard || sc_s_out == NULL)
		sc_s_out = "";

	sc_u_in = tgetstr("us", &sp);
	if (hard || sc_u_in == NULL)
		sc_u_in = sc_s_in;

	sc_u_out = tgetstr("ue", &sp);
	if (hard || sc_u_out == NULL)
		sc_u_out = sc_s_out;

	sc_b_in = tgetstr("md", &sp);
	if (hard || sc_b_in == NULL)
	{
		sc_b_in = sc_s_in;
		sc_b_out = sc_s_out;
	} else
	{
		sc_b_out = tgetstr("me", &sp);
		if (hard || sc_b_out == NULL)
			sc_b_out = "";
	}

	sc_home = tgetstr("ho", &sp);
	if (hard || sc_home == NULL || *sc_home == '\0')
	{
		if (*sc_move == '\0')
		{
			/*
			 * This last resort for sc_home is supposed to
			 * be an up-arrow suggesting moving to the 
			 * top of the "virtual screen". (The one in
			 * your imagination as you try to use this on
			 * a hard copy terminal.)
			 */
			sc_home = "|\b^";
		} else
		{
			/* 
			 * No "home" string,
			 * but we can use "move(0,0)".
			 */
			(void)strcpy(sp, tgoto(sc_move, 0, 0));
			sc_home = sp;
			sp += strlen(sp) + 1;
		}
	}

	sc_lower_left = tgetstr("ll", &sp);
	if (hard || sc_lower_left == NULL || *sc_lower_left == '\0')
	{
		if (*sc_move == '\0')
		{
			sc_lower_left = "\r";
		} else
		{
			/*
			 * No "lower-left" string, 
			 * but we can use "move(0,last-line)".
			 */
			(void)strcpy(sp, tgoto(sc_move, 0, sc_height-1));
			sc_lower_left = sp;
			sp += strlen(sp) + 1;
		}
	}

	/*
	 * To add a line at top of screen and scroll the display down,
	 * we use "al" (add line) or "sr" (scroll reverse).
	 */
	if ((sc_addline = tgetstr("al", &sp)) == NULL || 
		 *sc_addline == '\0')
		sc_addline = tgetstr("sr", &sp);

	if (hard || sc_addline == NULL || *sc_addline == '\0')
	{
		sc_addline = "";
		/* Force repaint on any backward movement */
		back_scroll = 0;
	}

	if (tgetflag("bs"))
		sc_backspace = "\b";
	else
	{
		sc_backspace = tgetstr("bc", &sp);
		if (sc_backspace == NULL || *sc_backspace == '\0')
			sc_backspace = "\b";
	}
}


/*
 * Below are the functions which perform all the 
 * terminal-specific screen manipulation.
 */

int putchr();

/*
 * Initialize terminal
 */
init()
{
	tputs(sc_init, sc_height, putchr);
}

/*
 * Deinitialize terminal
 */
deinit()
{
	tputs(sc_deinit, sc_height, putchr);
}

/*
 * Home cursor (move to upper left corner of screen).
 */
home()
{
	tputs(sc_home, 1, putchr);
}

/*
 * Add a blank line (called with cursor at home).
 * Should scroll the display down.
 */
add_line()
{
	tputs(sc_addline, sc_height, putchr);
}

int short_file;				/* if file less than a screen */
lower_left()
{
	if (short_file) {
		putchr('\r');
		flush();
	}
	else
		tputs(sc_lower_left, 1, putchr);
}

/*
 * Ring the terminal bell.
 */
bell()
{
	putchr('\7');
}

/*
 * Clear the screen.
 */
clear()
{
	tputs(sc_clear, sc_height, putchr);
}

/*
 * Clear from the cursor to the end of the cursor's line.
 * {{ This must not move the cursor. }}
 */
clear_eol()
{
	tputs(sc_eol_clear, 1, putchr);
}

/*
 * Begin "standout" (bold, underline, or whatever).
 */
so_enter()
{
	tputs(sc_s_in, 1, putchr);
}

/*
 * End "standout".
 */
so_exit()
{
	tputs(sc_s_out, 1, putchr);
}

/*
 * Begin "underline" (hopefully real underlining, 
 * otherwise whatever the terminal provides).
 */
ul_enter()
{
	tputs(sc_u_in, 1, putchr);
}

/*
 * End "underline".
 */
ul_exit()
{
	tputs(sc_u_out, 1, putchr);
}

/*
 * Begin "bold"
 */
bo_enter()
{
	tputs(sc_b_in, 1, putchr);
}

/*
 * End "bold".
 */
bo_exit()
{
	tputs(sc_b_out, 1, putchr);
}

/*
 * Erase the character to the left of the cursor 
 * and move the cursor left.
 */
backspace()
{
	/* 
	 * Try to erase the previous character by overstriking with a space.
	 */
	tputs(sc_backspace, 1, putchr);
	putchr(' ');
	tputs(sc_backspace, 1, putchr);
}

/*
 * Output a plain backspace, without erasing the previous char.
 */
putbs()
{
	tputs(sc_backspace, 1, putchr);
}
Commit	Line	Data
bfe13c81 KB	1	/*
	2	* Copyright (c) 1988 Mark Nudleman
	3	* Copyright (c) 1988 Regents of the University of California.
	4	* All rights reserved.
	5	*
f15db449	6	* %sccs.include.redist.c%
bfe13c81 KB	7	*/
	8
	9	#ifndef lint
f15db449	10	static char sccsid[] = "@(#)screen.c 5.7 (Berkeley) %G%";
bfe13c81 KB	11	#endif /* not lint */
	12
	13	/*
	14	* Routines which deal with the characteristics of the terminal.
	15	* Uses termcap to be as terminal-independent as possible.
	16	*
	17	* {{ Someday this should be rewritten to use curses. }}
	18	*/
	19
966c6ec0 KB	20	#include <stdio.h>
966c6ec0 KB	21	#include <less.h>
bfe13c81 KB	22
	23	#if TERMIO
	24	#include <termio.h>
	25	#else
	26	#include <sgtty.h>
	27	#endif
	28
	29	#ifdef TIOCGWINSZ
	30	#include <sys/ioctl.h>
	31	#else
	32	/*
	33	* For the Unix PC (ATT 7300 & 3B1):
	34	* Since WIOCGETD is defined in sys/window.h, we can't use that to decide
	35	* whether to include sys/window.h. Use SIGPHONE from sys/signal.h instead.
	36	*/
	37	#include <sys/signal.h>
	38	#ifdef SIGPHONE
	39	#include <sys/window.h>
	40	#endif
	41	#endif
	42
	43	/*
	44	* Strings passed to tputs() to do various terminal functions.
	45	*/
	46	static char
	47	sc_pad, / Pad string */
	48	sc_home, / Cursor home */
	49	sc_addline, / Add line, scroll down following lines */
	50	sc_lower_left, / Cursor to last line, first column */
	51	sc_move, / General cursor positioning */
	52	sc_clear, / Clear screen */
	53	sc_eol_clear, / Clear to end of line */
	54	sc_s_in, / Enter standout (highlighted) mode */
	55	sc_s_out, / Exit standout mode */
	56	sc_u_in, / Enter underline mode */
	57	sc_u_out, / Exit underline mode */
	58	sc_b_in, / Enter bold mode */
	59	sc_b_out, / Exit bold mode */
bfe13c81 KB	60	sc_backspace, / Backspace cursor */
	61	sc_init, / Startup terminal initialization */
	62	sc_deinit; / Exit terminal de-intialization */
	63
966c6ec0 KB	64	int auto_wrap; /* Terminal does \r\n when write past margin */
	65	int ignaw; /* Terminal ignores \n immediately after wrap */
	66	/* The user's erase and line-kill chars */
	67	int erase_char, kill_char, werase_char;
	68	int sc_width, sc_height = -1; /* Height & width of screen */
	69	int sc_window = -1; /* window size for forward and backward */
	70	int bo_width, be_width; /* Printing width of boldface sequences */
	71	int ul_width, ue_width; /* Printing width of underline sequences */
	72	int so_width, se_width; /* Printing width of standout sequences */
bfe13c81 KB	73
	74	/*
	75	* These two variables are sometimes defined in,
	76	* and needed by, the termcap library.
	77	* It may be necessary on some systems to declare them extern here.
	78	*/
	79	/extern/ short ospeed; /* Terminal output baud rate */
	80	/extern/ char PC; /* Pad character */
	81
bfe13c81 KB	82	extern int back_scroll;
	83	char *tgetstr();
	84	char *tgoto();
	85
	86	/*
	87	* Change terminal to "raw mode", or restore to "normal" mode.
	88	* "Raw mode" means
	89	* 1. An outstanding read will complete on receipt of a single keystroke.
	90	* 2. Input is not echoed.
	91	* 3. On output, \n is mapped to \r\n.
	92	* 4. \t is NOT expanded into spaces.
	93	* 5. Signal-causing characters such as ctrl-C (interrupt),
	94	* etc. are NOT disabled.
	95	* It doesn't matter whether an input \n is mapped to \r, or vice versa.
	96	*/
bfe13c81 KB	97	raw_mode(on)
	98	int on;
	99	{
	100	#if TERMIO
	101	struct termio s;
	102	static struct termio save_term;
	103
	104	if (on)
	105	{
	106	/*
	107	* Get terminal modes.
	108	*/
966c6ec0	109	(void)ioctl(2, TCGETA, &s);
bfe13c81 KB	110
	111	/*
	112	* Save modes and set certain variables dependent on modes.
	113	*/
	114	save_term = s;
	115	ospeed = s.c_cflag & CBAUD;
	116	erase_char = s.c_cc[VERASE];
	117	kill_char = s.c_cc[VKILL];
966c6ec0	118	werase_char = s.c_cc[VWERASE];
bfe13c81 KB	119
	120	/*
	121	* Set the modes to the way we want them.
	122	*/
	123	s.c_lflag &= ~(ICANON\|ECHO\|ECHOE\|ECHOK\|ECHONL);
	124	s.c_oflag \|= (OPOST\|ONLCR\|TAB3);
	125	s.c_oflag &= ~(OCRNL\|ONOCR\|ONLRET);
	126	s.c_cc[VMIN] = 1;
	127	s.c_cc[VTIME] = 0;
	128	} else
	129	{
	130	/*
	131	* Restore saved modes.
	132	*/
	133	s = save_term;
	134	}
966c6ec0	135	(void)ioctl(2, TCSETAW, &s);
bfe13c81 KB	136	#else
	137	struct sgttyb s;
	138	static struct sgttyb save_term;
	139
	140	if (on)
	141	{
	142	/*
	143	* Get terminal modes.
	144	*/
966c6ec0	145	(void)ioctl(2, TIOCGETP, &s);
bfe13c81 KB	146
	147	/*
	148	* Save modes and set certain variables dependent on modes.
	149	*/
	150	save_term = s;
	151	ospeed = s.sg_ospeed;
	152	erase_char = s.sg_erase;
	153	kill_char = s.sg_kill;
966c6ec0	154	werase_char = -1;
bfe13c81 KB	155
	156	/*
	157	* Set the modes to the way we want them.
	158	*/
	159	s.sg_flags \|= CBREAK;
	160	s.sg_flags &= ~(ECHO\|XTABS);
	161	} else
	162	{
	163	/*
	164	* Restore saved modes.
	165	*/
	166	s = save_term;
	167	}
966c6ec0	168	(void)ioctl(2, TIOCSETN, &s);
bfe13c81 KB	169	#endif
	170	}
	171
bfe13c81 KB	172	/*
	173	* Get terminal capabilities via termcap.
	174	*/
bfe13c81 KB	175	get_term()
	176	{
	177	char termbuf[2048];
	178	char *sp;
	179	char *term;
	180	int hard;
	181	#ifdef TIOCGWINSZ
	182	struct winsize w;
	183	#else
	184	#ifdef WIOCGETD
	185	struct uwdata w;
	186	#endif
	187	#endif
	188	static char sbuf[1024];
	189
bd410f1f	190	char getenv(), strcpy();
bfe13c81 KB	191
	192	/*
	193	* Find out what kind of terminal this is.
	194	*/
	195	if ((term = getenv("TERM")) == NULL)
	196	term = "unknown";
	197	if (tgetent(termbuf, term) <= 0)
bd410f1f	198	(void)strcpy(termbuf, "dumb:co#80:hc:");
bfe13c81 KB	199
	200	/*
	201	* Get size of the screen.
	202	*/
	203	#ifdef TIOCGWINSZ
4a7551ea KB	204	if (ioctl(2, TIOCGWINSZ, &w) == 0 && w.ws_row > 0)
4a7551ea KB	205	sc_height = w.ws_row;
bfe13c81 KB	206	#else
bfe13c81 KB	207	#ifdef WIOCGETD
4a7551ea KB	208	if (ioctl(2, WIOCGETD, &w) == 0 && w.uw_height > 0)
4a7551ea KB	209	sc_height = w.uw_height/w.uw_vs;
bfe13c81 KB	210	#endif
bfe13c81 KB	211	#endif
4a7551ea KB	212	else
4a7551ea KB	213	sc_height = tgetnum("li");
966c6ec0 KB	214	hard = (sc_height < 0 \|\| tgetflag("hc"));
966c6ec0 KB	215	if (hard) {
bfe13c81 KB	216	/* Oh no, this is a hardcopy terminal. */
	217	sc_height = 24;
	218	}
	219
	220	#ifdef TIOCGWINSZ
	221	if (ioctl(2, TIOCGWINSZ, &w) == 0 && w.ws_col > 0)
	222	sc_width = w.ws_col;
	223	else
	224	#ifdef WIOCGETD
	225	if (ioctl(2, WIOCGETD, &w) == 0 && w.uw_width > 0)
	226	sc_width = w.uw_width/w.uw_hs;
	227	else
	228	#endif
	229	#endif
	230	sc_width = tgetnum("co");
	231	if (sc_width < 0)
	232	sc_width = 80;
	233
	234	auto_wrap = tgetflag("am");
	235	ignaw = tgetflag("xn");
	236
	237	/*
	238	* Assumes termcap variable "sg" is the printing width of
	239	* the standout sequence, the end standout sequence,
	240	* the underline sequence, the end underline sequence,
	241	* the boldface sequence, and the end boldface sequence.
	242	*/
	243	if ((so_width = tgetnum("sg")) < 0)
	244	so_width = 0;
	245	be_width = bo_width = ue_width = ul_width = se_width = so_width;
	246
	247	/*
	248	* Get various string-valued capabilities.
	249	*/
	250	sp = sbuf;
	251
	252	sc_pad = tgetstr("pc", &sp);
	253	if (sc_pad != NULL)
	254	PC = *sc_pad;
	255
	256	sc_init = tgetstr("ti", &sp);
	257	if (sc_init == NULL)
	258	sc_init = "";
	259
	260	sc_deinit= tgetstr("te", &sp);
	261	if (sc_deinit == NULL)
	262	sc_deinit = "";
	263
	264	sc_eol_clear = tgetstr("ce", &sp);
	265	if (hard \|\| sc_eol_clear == NULL \|\| *sc_eol_clear == '\0')
	266	{
bfe13c81 KB	267	sc_eol_clear = "";
	268	}
	269
	270	sc_clear = tgetstr("cl", &sp);
	271	if (hard \|\| sc_clear == NULL \|\| *sc_clear == '\0')
	272	{
bfe13c81 KB	273	sc_clear = "\n\n";
	274	}
	275
	276	sc_move = tgetstr("cm", &sp);
	277	if (hard \|\| sc_move == NULL \|\| *sc_move == '\0')
	278	{
	279	/*
	280	* This is not an error here, because we don't
	281	* always need sc_move.
	282	* We need it only if we don't have home or lower-left.
	283	*/
	284	sc_move = "";
	285	}
	286
	287	sc_s_in = tgetstr("so", &sp);
	288	if (hard \|\| sc_s_in == NULL)
	289	sc_s_in = "";
	290
	291	sc_s_out = tgetstr("se", &sp);
	292	if (hard \|\| sc_s_out == NULL)
	293	sc_s_out = "";
	294
	295	sc_u_in = tgetstr("us", &sp);
	296	if (hard \|\| sc_u_in == NULL)
	297	sc_u_in = sc_s_in;
	298
	299	sc_u_out = tgetstr("ue", &sp);
	300	if (hard \|\| sc_u_out == NULL)
	301	sc_u_out = sc_s_out;
	302
	303	sc_b_in = tgetstr("md", &sp);
	304	if (hard \|\| sc_b_in == NULL)
	305	{
	306	sc_b_in = sc_s_in;
	307	sc_b_out = sc_s_out;
	308	} else
	309	{
	310	sc_b_out = tgetstr("me", &sp);
	311	if (hard \|\| sc_b_out == NULL)
	312	sc_b_out = "";
	313	}
	314
bfe13c81 KB	315	sc_home = tgetstr("ho", &sp);
	316	if (hard \|\| sc_home == NULL \|\| *sc_home == '\0')
	317	{
	318	if (*sc_move == '\0')
	319	{
bfe13c81 KB	320	/*
	321	* This last resort for sc_home is supposed to
	322	* be an up-arrow suggesting moving to the
	323	* top of the "virtual screen". (The one in
	324	* your imagination as you try to use this on
	325	* a hard copy terminal.)
	326	*/
b2796622	327	sc_home = "\|\b^";
bfe13c81 KB	328	} else
	329	{
	330	/*
	331	* No "home" string,
	332	* but we can use "move(0,0)".
	333	*/
bd410f1f	334	(void)strcpy(sp, tgoto(sc_move, 0, 0));
bfe13c81 KB	335	sc_home = sp;
	336	sp += strlen(sp) + 1;
	337	}
	338	}
	339
	340	sc_lower_left = tgetstr("ll", &sp);
	341	if (hard \|\| sc_lower_left == NULL \|\| *sc_lower_left == '\0')
	342	{
	343	if (*sc_move == '\0')
	344	{
bfe13c81 KB	345	sc_lower_left = "\r";
	346	} else
	347	{
	348	/*
	349	* No "lower-left" string,
	350	* but we can use "move(0,last-line)".
	351	*/
bd410f1f	352	(void)strcpy(sp, tgoto(sc_move, 0, sc_height-1));
bfe13c81 KB	353	sc_lower_left = sp;
	354	sp += strlen(sp) + 1;
	355	}
	356	}
	357
	358	/*
	359	* To add a line at top of screen and scroll the display down,
	360	* we use "al" (add line) or "sr" (scroll reverse).
	361	*/
	362	if ((sc_addline = tgetstr("al", &sp)) == NULL \|\|
	363	*sc_addline == '\0')
	364	sc_addline = tgetstr("sr", &sp);
	365
	366	if (hard \|\| sc_addline == NULL \|\| *sc_addline == '\0')
	367	{
bfe13c81 KB	368	sc_addline = "";
	369	/* Force repaint on any backward movement */
	370	back_scroll = 0;
	371	}
	372
	373	if (tgetflag("bs"))
	374	sc_backspace = "\b";
	375	else
	376	{
	377	sc_backspace = tgetstr("bc", &sp);
	378	if (sc_backspace == NULL \|\| *sc_backspace == '\0')
	379	sc_backspace = "\b";
	380	}
	381	}
	382
	383
	384	/*
	385	* Below are the functions which perform all the
	386	* terminal-specific screen manipulation.
	387	*/
	388
966c6ec0	389	int putchr();
bfe13c81 KB	390
	391	/*
	392	* Initialize terminal
	393	*/
bfe13c81 KB	394	init()
	395	{
	396	tputs(sc_init, sc_height, putchr);
	397	}
	398
	399	/*
	400	* Deinitialize terminal
	401	*/
bfe13c81 KB	402	deinit()
	403	{
	404	tputs(sc_deinit, sc_height, putchr);
	405	}
	406
	407	/*
	408	* Home cursor (move to upper left corner of screen).
	409	*/
bfe13c81 KB	410	home()
	411	{
	412	tputs(sc_home, 1, putchr);
	413	}
	414
	415	/*
	416	* Add a blank line (called with cursor at home).
	417	* Should scroll the display down.
	418	*/
bfe13c81 KB	419	add_line()
	420	{
	421	tputs(sc_addline, sc_height, putchr);
	422	}
	423
4a7551ea	424	int short_file; /* if file less than a screen */
bfe13c81 KB	425	lower_left()
bfe13c81 KB	426	{
4a7551ea KB	427	if (short_file) {
	428	putchr('\r');
	429	flush();
	430	}
	431	else
	432	tputs(sc_lower_left, 1, putchr);
bfe13c81 KB	433	}
	434
	435	/*
	436	* Ring the terminal bell.
	437	*/
bfe13c81 KB	438	bell()
bfe13c81 KB	439	{
966c6ec0	440	putchr('\7');
bfe13c81 KB	441	}
	442
	443	/*
	444	* Clear the screen.
	445	*/
bfe13c81 KB	446	clear()
	447	{
	448	tputs(sc_clear, sc_height, putchr);
	449	}
	450
	451	/*
	452	* Clear from the cursor to the end of the cursor's line.
	453	* {{ This must not move the cursor. }}
	454	*/
bfe13c81 KB	455	clear_eol()
	456	{
	457	tputs(sc_eol_clear, 1, putchr);
	458	}
	459
	460	/*
	461	* Begin "standout" (bold, underline, or whatever).
	462	*/
bfe13c81 KB	463	so_enter()
	464	{
	465	tputs(sc_s_in, 1, putchr);
	466	}
	467
	468	/*
	469	* End "standout".
	470	*/
bfe13c81 KB	471	so_exit()
	472	{
	473	tputs(sc_s_out, 1, putchr);
	474	}
	475
	476	/*
	477	* Begin "underline" (hopefully real underlining,
	478	* otherwise whatever the terminal provides).
	479	*/
bfe13c81 KB	480	ul_enter()
	481	{
	482	tputs(sc_u_in, 1, putchr);
	483	}
	484
	485	/*
	486	* End "underline".
	487	*/
bfe13c81 KB	488	ul_exit()
	489	{
	490	tputs(sc_u_out, 1, putchr);
	491	}
	492
	493	/*
	494	* Begin "bold"
	495	*/
bfe13c81 KB	496	bo_enter()
	497	{
	498	tputs(sc_b_in, 1, putchr);
	499	}
	500
	501	/*
	502	* End "bold".
	503	*/
bfe13c81 KB	504	bo_exit()
	505	{
	506	tputs(sc_b_out, 1, putchr);
	507	}
	508
	509	/*
	510	* Erase the character to the left of the cursor
	511	* and move the cursor left.
	512	*/
bfe13c81 KB	513	backspace()
	514	{
	515	/*
	516	* Try to erase the previous character by overstriking with a space.
	517	*/
	518	tputs(sc_backspace, 1, putchr);
	519	putchr(' ');
	520	tputs(sc_backspace, 1, putchr);
	521	}
	522
	523	/*
	524	* Output a plain backspace, without erasing the previous char.
	525	*/
bfe13c81 KB	526	putbs()
	527	{
	528	tputs(sc_backspace, 1, putchr);
	529	}