xref: /openbsd-src/lib/libcurses/tty/lib_mvcur.c (revision 92dd1ec0a89df25171bc5d61a3d95ea1a68cef0b)
1 /*	$OpenBSD: lib_mvcur.c,v 1.1 1999/01/18 19:10:26 millert Exp $	*/
2 
3 /****************************************************************************
4  * Copyright (c) 1998 Free Software Foundation, Inc.                        *
5  *                                                                          *
6  * Permission is hereby granted, free of charge, to any person obtaining a  *
7  * copy of this software and associated documentation files (the            *
8  * "Software"), to deal in the Software without restriction, including      *
9  * without limitation the rights to use, copy, modify, merge, publish,      *
10  * distribute, distribute with modifications, sublicense, and/or sell       *
11  * copies of the Software, and to permit persons to whom the Software is    *
12  * furnished to do so, subject to the following conditions:                 *
13  *                                                                          *
14  * The above copyright notice and this permission notice shall be included  *
15  * in all copies or substantial portions of the Software.                   *
16  *                                                                          *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
19  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
20  * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
21  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
22  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
23  * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
24  *                                                                          *
25  * Except as contained in this notice, the name(s) of the above copyright   *
26  * holders shall not be used in advertising or otherwise to promote the     *
27  * sale, use or other dealings in this Software without prior written       *
28  * authorization.                                                           *
29  ****************************************************************************/
30 
31 /****************************************************************************
32  *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
33  *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
34  ****************************************************************************/
35 
36 
37 /*
38 **	lib_mvcur.c
39 **
40 **	The routines for moving the physical cursor and scrolling:
41 **
42 **		void _nc_mvcur_init(void)
43 **
44 **		void _nc_mvcur_resume(void)
45 **
46 **		int mvcur(int old_y, int old_x, int new_y, int new_x)
47 **
48 **		void _nc_mvcur_wrap(void)
49 **
50 ** Comparisons with older movement optimizers:
51 **    SVr3 curses mvcur() can't use cursor_to_ll or auto_left_margin.
52 **    4.4BSD curses can't use cuu/cud/cuf/cub/hpa/vpa/tab/cbt for local
53 ** motions.  It doesn't use tactics based on auto_left_margin.  Weirdly
54 ** enough, it doesn't use its own hardware-scrolling routine to scroll up
55 ** destination lines for out-of-bounds addresses!
56 **    old ncurses optimizer: less accurate cost computations (in fact,
57 ** it was broken and had to be commented out!).
58 **
59 ** Compile with -DMAIN to build an interactive tester/timer for the movement
60 ** optimizer.  You can use it to investigate the optimizer's behavior.
61 ** You can also use it for tuning the formulas used to determine whether
62 ** or not full optimization is attempted.
63 **
64 ** This code has a nasty tendency to find bugs in terminfo entries, because it
65 ** exercises the non-cup movement capabilities heavily.  If you think you've
66 ** found a bug, try deleting subsets of the following capabilities (arranged
67 ** in decreasing order of suspiciousness): it, tab, cbt, hpa, vpa, cuu, cud,
68 ** cuf, cub, cuu1, cud1, cuf1, cub1.  It may be that one or more are wrong.
69 **
70 ** Note: you should expect this code to look like a resource hog in a profile.
71 ** That's because it does a lot of I/O, through the tputs() calls.  The I/O
72 ** cost swamps the computation overhead (and as machines get faster, this
73 ** will become even more true).  Comments in the test exerciser at the end
74 ** go into detail about tuning and how you can gauge the optimizer's
75 ** effectiveness.
76 **/
77 
78 /****************************************************************************
79  *
80  * Constants and macros for optimizer tuning.
81  *
82  ****************************************************************************/
83 
84 /*
85  * The average overhead of a full optimization computation in character
86  * transmission times.  If it's too high, the algorithm will be a bit
87  * over-biased toward using cup rather than local motions; if it's too
88  * low, the algorithm may spend more time than is strictly optimal
89  * looking for non-cup motions.  Profile the optimizer using the `t'
90  * command of the exerciser (see below), and round to the nearest integer.
91  *
92  * Yes, I (esr) thought about computing expected overhead dynamically, say
93  * by derivation from a running average of optimizer times.  But the
94  * whole point of this optimization is to *decrease* the frequency of
95  * system calls. :-)
96  */
97 #define COMPUTE_OVERHEAD	1	/* I use a 90MHz Pentium @ 9.6Kbps */
98 
99 /*
100  * LONG_DIST is the distance we consider to be just as costly to move over as a
101  * cup sequence is to emit.  In other words, it's the length of a cup sequence
102  * adjusted for average computation overhead.  The magic number is the length
103  * of "\033[yy;xxH", the typical cup sequence these days.
104  */
105 #define LONG_DIST		(8 - COMPUTE_OVERHEAD)
106 
107 /*
108  * Tell whether a motion is optimizable by local motions.  Needs to be cheap to
109  * compute. In general, all the fast moves go to either the right or left edge
110  * of the screen.  So any motion to a location that is (a) further away than
111  * LONG_DIST and (b) further inward from the right or left edge than LONG_DIST,
112  * we'll consider nonlocal.
113  */
114 #define NOT_LOCAL(fy, fx, ty, tx)	((tx > LONG_DIST) && (tx < screen_lines - 1 - LONG_DIST) && (abs(ty-fy) + abs(tx-fx) > LONG_DIST))
115 
116 /****************************************************************************
117  *
118  * External interfaces
119  *
120  ****************************************************************************/
121 
122 /*
123  * For this code to work OK, the following components must live in the
124  * screen structure:
125  *
126  *	int		_char_padding;	// cost of character put
127  *	int		_cr_cost;	// cost of (carriage_return)
128  *	int		_cup_cost;	// cost of (cursor_address)
129  *	int		_home_cost;	// cost of (cursor_home)
130  *	int		_ll_cost;	// cost of (cursor_to_ll)
131  *#if USE_HARD_TABS
132  *	int		_ht_cost;	// cost of (tab)
133  *	int		_cbt_cost;	// cost of (back_tab)
134  *#endif USE_HARD_TABS
135  *	int		_cub1_cost;	// cost of (cursor_left)
136  *	int		_cuf1_cost;	// cost of (cursor_right)
137  *	int		_cud1_cost;	// cost of (cursor_down)
138  *	int		_cuu1_cost;	// cost of (cursor_up)
139  *	int		_cub_cost;	// cost of (parm_cursor_left)
140  *	int		_cuf_cost;	// cost of (parm_cursor_right)
141  *	int		_cud_cost;	// cost of (parm_cursor_down)
142  *	int		_cuu_cost;	// cost of (parm_cursor_up)
143  *	int		_hpa_cost;	// cost of (column_address)
144  *	int		_vpa_cost;	// cost of (row_address)
145  *	int		_ech_cost;	// cost of (erase_chars)
146  *	int		_rep_cost;	// cost of (repeat_char)
147  *
148  * The USE_HARD_TABS switch controls whether it is reliable to use tab/backtabs
149  * for local motions.  On many systems, it's not, due to uncertainties about
150  * tab delays and whether or not tabs will be expanded in raw mode.  If you
151  * have parm_right_cursor, tab motions don't win you a lot anyhow.
152  */
153 
154 #include <curses.priv.h>
155 #include <term.h>
156 #include <ctype.h>
157 
158 MODULE_ID("$From: lib_mvcur.c,v 1.55 1998/12/05 02:04:48 tom Exp $")
159 
160 #define STRLEN(s)       (s != 0) ? strlen(s) : 0
161 
162 #define CURRENT_ATTR	SP->_current_attr	/* current phys attribute */
163 #define CURRENT_ROW	SP->_cursrow		/* phys cursor row */
164 #define CURRENT_COLUMN	SP->_curscol		/* phys cursor column */
165 #define REAL_ATTR	SP->_current_attr	/* phys current attribute */
166 #define WANT_CHAR(y, x)	SP->_newscr->_line[y].text[x]	/* desired state */
167 #define BAUDRATE	cur_term->_baudrate	/* bits per second */
168 
169 #if defined(MAIN) || defined(NCURSES_TEST)
170 #include <sys/time.h>
171 
172 static bool profiling = FALSE;
173 static float diff;
174 #endif /* MAIN */
175 
176 #define OPT_SIZE 512
177 
178 static int normalized_cost(const char *const cap, int affcnt);
179 
180 /****************************************************************************
181  *
182  * Initialization/wrapup (including cost pre-computation)
183  *
184  ****************************************************************************/
185 
186 #ifdef TRACE
187 static int
188 trace_cost_of(const char *capname, const char *cap, int affcnt)
189 {
190 	int result = _nc_msec_cost(cap,affcnt);
191 	TR(TRACE_CHARPUT|TRACE_MOVE, ("CostOf %s %d", capname, result));
192 	return result;
193 }
194 #define CostOf(cap,affcnt) trace_cost_of(#cap,cap,affcnt);
195 
196 static int
197 trace_normalized_cost(const char *capname, const char *cap, int affcnt)
198 {
199 	int result = normalized_cost(cap,affcnt);
200 	TR(TRACE_CHARPUT|TRACE_MOVE, ("NormalizedCost %s %d", capname, result));
201 	return result;
202 }
203 #define NormalizedCost(cap,affcnt) trace_normalized_cost(#cap,cap,affcnt);
204 
205 #else
206 
207 #define CostOf(cap,affcnt) _nc_msec_cost(cap,affcnt);
208 #define NormalizedCost(cap,affcnt) normalized_cost(cap,affcnt);
209 
210 #endif
211 
212 int _nc_msec_cost(const char *const cap, int affcnt)
213 /* compute the cost of a given operation */
214 {
215     if (cap == 0)
216 	return(INFINITY);
217     else
218     {
219 	const	char	*cp;
220 	float	cum_cost = 0;
221 
222 	for (cp = cap; *cp; cp++)
223 	{
224 	    /* extract padding, either mandatory or required */
225 	    if (cp[0] == '$' && cp[1] == '<' && strchr(cp, '>'))
226 	    {
227 		float	number = 0;
228 
229 		for (cp += 2; *cp != '>'; cp++)
230 		{
231 		    if (isdigit(*cp))
232 			number = number * 10 + (*cp - '0');
233 		    else if (*cp == '.')
234 			number += (*++cp - 10) / 10.0;
235 		    else if (*cp == '*')
236 			number *= affcnt;
237 		}
238 
239 		cum_cost += number * 10;
240 	    }
241 	    else
242 		cum_cost += SP->_char_padding;
243 	}
244 
245 	return((int)cum_cost);
246     }
247 }
248 
249 static int normalized_cost(const char *const cap, int affcnt)
250 /* compute the effective character-count for an operation (round up) */
251 {
252 	int cost = _nc_msec_cost(cap, affcnt);
253 	if (cost != INFINITY)
254 		cost = (cost + SP->_char_padding - 1) / SP->_char_padding;
255 	return cost;
256 }
257 
258 static void reset_scroll_region(void)
259 /* Set the scroll-region to a known state (the default) */
260 {
261     if (change_scroll_region)
262     {
263 	TPUTS_TRACE("change_scroll_region");
264 	putp(tparm(change_scroll_region, 0, screen_lines - 1));
265     }
266 }
267 
268 void _nc_mvcur_resume(void)
269 /* what to do at initialization time and after each shellout */
270 {
271     /* initialize screen for cursor access */
272     if (enter_ca_mode)
273     {
274 	TPUTS_TRACE("enter_ca_mode");
275 	putp(enter_ca_mode);
276     }
277 
278     /*
279      * Doing this here rather than in _nc_mvcur_wrap() ensures that
280      * ncurses programs will see a reset scroll region even if a
281      * program that messed with it died ungracefully.
282      *
283      * This also undoes the effects of terminal init strings that assume
284      * they know the screen size.  This is useful when you're running
285      * a vt100 emulation through xterm.
286      */
287     reset_scroll_region();
288     SP->_cursrow = SP->_curscol = -1;
289 
290     /* restore cursor shape */
291     if (SP->_cursor != -1)
292     {
293 	int cursor = SP->_cursor;
294 	SP->_cursor = -1;
295 	curs_set (cursor);
296     }
297 }
298 
299 void _nc_mvcur_init(void)
300 /* initialize the cost structure */
301 {
302     /*
303      * 9 = 7 bits + 1 parity + 1 stop.
304      */
305     SP->_char_padding = (9 * 1000 * 10) / (BAUDRATE > 0 ? BAUDRATE : 9600);
306     if (SP->_char_padding <= 0)
307 	SP->_char_padding = 1;	/* must be nonzero */
308     TR(TRACE_CHARPUT|TRACE_MOVE, ("char_padding %d msecs", SP->_char_padding));
309 
310     /* non-parameterized local-motion strings */
311     SP->_cr_cost   = CostOf(carriage_return, 0);
312     SP->_home_cost = CostOf(cursor_home, 0);
313     SP->_ll_cost   = CostOf(cursor_to_ll, 0);
314 #if USE_HARD_TABS
315     SP->_ht_cost   = CostOf(tab, 0);
316     SP->_cbt_cost  = CostOf(back_tab, 0);
317 #endif /* USE_HARD_TABS */
318     SP->_cub1_cost = CostOf(cursor_left, 0);
319     SP->_cuf1_cost = CostOf(cursor_right, 0);
320     SP->_cud1_cost = CostOf(cursor_down, 0);
321     SP->_cuu1_cost = CostOf(cursor_up, 0);
322 
323     SP->_smir_cost = CostOf(enter_insert_mode, 0);
324     SP->_rmir_cost = CostOf(exit_insert_mode, 0);
325     SP->_ip_cost = 0;
326     if (insert_padding) {
327 	SP->_ip_cost = CostOf(insert_padding, 0);
328     }
329 
330     /*
331      * Assumption: if the terminal has memory_relative addressing, the
332      * initialization strings or smcup will set single-page mode so we
333      * can treat it like absolute screen addressing.  This seems to be true
334      * for all cursor_mem_address terminal types in the terminfo database.
335      */
336     SP->_address_cursor = cursor_address ? cursor_address : cursor_mem_address;
337 
338     /*
339      * Parametrized local-motion strings.  This static cost computation
340      * depends on the following assumptions:
341      *
342      * (1) They never have * padding.  In the entire master terminfo database
343      *     as of March 1995, only the obsolete Zenith Z-100 pc violates this.
344      *	   (Proportional padding is found mainly in insert, delete and scroll
345      *     capabilities).
346      *
347      * (2) The average case of cup has two two-digit parameters.  Strictly,
348      *     the average case for a 24 * 80 screen has ((10*10*(1 + 1)) +
349      *     (14*10*(1 + 2)) + (10*70*(2 + 1)) + (14*70*4)) / (24*80) = 3.458
350      *     digits of parameters.  On a 25x80 screen the average is 3.6197.
351      *     On larger screens the value gets much closer to 4.
352      *
353      * (3) The average case of cub/cuf/hpa/ech/rep has 2 digits of parameters
354      *     (strictly, (((10 * 1) + (70 * 2)) / 80) = 1.8750).
355      *
356      * (4) The average case of cud/cuu/vpa has 2 digits of parameters
357      *     (strictly, (((10 * 1) + (14 * 2)) / 24) = 1.5833).
358      *
359      * All these averages depend on the assumption that all parameter values
360      * are equally probable.
361      */
362     SP->_cup_cost  = CostOf(tparm(SP->_address_cursor, 23, 23), 1);
363     SP->_cub_cost  = CostOf(tparm(parm_left_cursor, 23), 1);
364     SP->_cuf_cost  = CostOf(tparm(parm_right_cursor, 23), 1);
365     SP->_cud_cost  = CostOf(tparm(parm_down_cursor, 23), 1);
366     SP->_cuu_cost  = CostOf(tparm(parm_up_cursor, 23), 1);
367     SP->_hpa_cost  = CostOf(tparm(column_address, 23), 1);
368     SP->_vpa_cost  = CostOf(tparm(row_address, 23), 1);
369 
370     /* non-parameterized screen-update strings */
371     SP->_ed_cost   = NormalizedCost(clr_eos, 1);
372     SP->_el_cost   = NormalizedCost(clr_eol, 1);
373     SP->_el1_cost  = NormalizedCost(clr_bol, 1);
374     SP->_dch1_cost = NormalizedCost(delete_character, 1);
375     SP->_ich1_cost = NormalizedCost(insert_character, 1);
376 
377     /* parameterized screen-update strings */
378     SP->_dch_cost  = NormalizedCost(tparm(parm_dch, 23), 1);
379     SP->_ich_cost  = NormalizedCost(tparm(parm_ich, 23), 1);
380     SP->_ech_cost  = NormalizedCost(tparm(erase_chars, 23), 1);
381     SP->_rep_cost  = NormalizedCost(tparm(repeat_char, ' ', 23), 1);
382 
383     SP->_cup_ch_cost = NormalizedCost(tparm(SP->_address_cursor, 23, 23), 1);
384     SP->_hpa_ch_cost = NormalizedCost(tparm(column_address, 23), 1);
385 
386     /* pre-compute some capability lengths */
387     SP->_carriage_return_length = STRLEN(carriage_return);
388     SP->_cursor_home_length     = STRLEN(cursor_home);
389     SP->_cursor_to_ll_length    = STRLEN(cursor_to_ll);
390 
391     /*
392      * A different, possibly better way to arrange this would be to set
393      * SP->_endwin = TRUE at window initialization time and let this be
394      * called by doupdate's return-from-shellout code.
395      */
396     _nc_mvcur_resume();
397 }
398 
399 void _nc_mvcur_wrap(void)
400 /* wrap up cursor-addressing mode */
401 {
402     /* leave cursor at screen bottom */
403     mvcur(-1, -1, screen_lines - 1, 0);
404 
405     /* set cursor to normal mode */
406     if (SP->_cursor != -1)
407 	curs_set(1);
408 
409     if (exit_ca_mode)
410     {
411 	TPUTS_TRACE("exit_ca_mode");
412 	putp(exit_ca_mode);
413     }
414     /*
415      * Reset terminal's tab counter.  There's a long-time bug that
416      * if you exit a "curses" program such as vi or more, tab
417      * forward, and then backspace, the cursor doesn't go to the
418      * right place.  The problem is that the kernel counts the
419      * escape sequences that reset things as column positions.
420      * Utter a \r to reset this invisibly.
421      */
422     _nc_outch('\r');
423 }
424 
425 /****************************************************************************
426  *
427  * Optimized cursor movement
428  *
429  ****************************************************************************/
430 
431 /*
432  * Perform repeated-append, returning cost
433  */
434 static inline int
435 repeated_append (int total, int num, int repeat, char *dst, const char *src)
436 {
437 	register size_t src_len = strlen(src);
438 	register size_t dst_len = STRLEN(dst);
439 
440 	if ((dst_len + repeat * src_len) < OPT_SIZE-1) {
441 		total += (num * repeat);
442 		if (dst) {
443 		    dst += dst_len;
444 		    while (repeat-- > 0) {
445 			(void) strcpy(dst, src);
446 			dst += src_len;
447 		    }
448 		}
449 	} else {
450 		total = INFINITY;
451 	}
452 	return total;
453 }
454 
455 #ifndef NO_OPTIMIZE
456 #define NEXTTAB(fr)	(fr + init_tabs - (fr % init_tabs))
457 
458 /*
459  * Assume back_tab (CBT) does not wrap backwards at the left margin, return
460  * a negative value at that point to simplify the loop.
461  */
462 #define LASTTAB(fr)	((fr > 0) ? ((fr - 1) / init_tabs) * init_tabs : -1)
463 
464 /* Note: we'd like to inline this for speed, but GNU C barfs on the attempt. */
465 
466 static int
467 relative_move(char *result, int from_y,int from_x,int to_y,int to_x, bool ovw)
468 /* move via local motions (cuu/cuu1/cud/cud1/cub1/cub/cuf1/cuf/vpa/hpa) */
469 {
470     int		n, vcost = 0, hcost = 0;
471 
472     if (result)
473 	result[0] = '\0';
474 
475     if (to_y != from_y)
476     {
477 	vcost = INFINITY;
478 
479 	if (row_address)
480 	{
481 	    if (result)
482 		(void) strcpy(result, tparm(row_address, to_y));
483 	    vcost = SP->_vpa_cost;
484 	}
485 
486 	if (to_y > from_y)
487 	{
488 	    n = (to_y - from_y);
489 
490 	    if (parm_down_cursor && SP->_cud_cost < vcost)
491 	    {
492 		if (result)
493 		    (void) strcpy(result, tparm(parm_down_cursor, n));
494 		vcost = SP->_cud_cost;
495 	    }
496 
497 	    if (cursor_down && (n * SP->_cud1_cost < vcost))
498 	    {
499 		if (result)
500 		    result[0] = '\0';
501 		vcost = repeated_append(0, SP->_cud1_cost, n, result, cursor_down);
502 	    }
503 	}
504 	else /* (to_y < from_y) */
505 	{
506 	    n = (from_y - to_y);
507 
508 	    if (parm_up_cursor && SP->_cup_cost < vcost)
509 	    {
510 		if (result)
511 		    (void) strcpy(result, tparm(parm_up_cursor, n));
512 		vcost = SP->_cup_cost;
513 	    }
514 
515 	    if (cursor_up && (n * SP->_cuu1_cost < vcost))
516 	    {
517 		if (result)
518 		    result[0] = '\0';
519 		vcost = repeated_append(0, SP->_cuu1_cost, n, result, cursor_up);
520 	    }
521 	}
522 
523 	if (vcost == INFINITY)
524 	    return(INFINITY);
525     }
526 
527     if (result)
528 	result += strlen(result);
529 
530     if (to_x != from_x)
531     {
532 	char	str[OPT_SIZE];
533 
534 	hcost = INFINITY;
535 
536 	if (column_address)
537 	{
538 	    if (result)
539 		(void) strcpy(result, tparm(column_address, to_x));
540 	    hcost = SP->_hpa_cost;
541 	}
542 
543 	if (to_x > from_x)
544 	{
545 	    n = to_x - from_x;
546 
547 	    if (parm_right_cursor && SP->_cuf_cost < hcost)
548 	    {
549 		if (result)
550 		    (void) strcpy(result, tparm(parm_right_cursor, n));
551 		hcost = SP->_cuf_cost;
552 	    }
553 
554 	    if (cursor_right)
555 	    {
556 		int	lhcost = 0;
557 
558 		str[0] = '\0';
559 
560 #if USE_HARD_TABS
561 		/* use hard tabs, if we have them, to do as much as possible */
562 		if (init_tabs > 0 && tab)
563 		{
564 		    int	nxt, fr;
565 
566 		    for (fr = from_x; (nxt = NEXTTAB(fr)) <= to_x; fr = nxt)
567 		    {
568 			lhcost = repeated_append(lhcost, SP->_ht_cost, 1, str, tab);
569 			if (lhcost == INFINITY)
570 				break;
571 		    }
572 
573 		    n = to_x - fr;
574 		    from_x = fr;
575 		}
576 #endif /* USE_HARD_TABS */
577 
578 #if defined(REAL_ATTR) && defined(WANT_CHAR)
579 #ifdef BSD_TPUTS
580 		/*
581 		 * If we're allowing BSD-style padding in tputs, don't generate
582 		 * a string with a leading digit.  Otherwise, that will be
583 		 * interpreted as a padding value rather than sent to the
584 		 * screen.
585 		 */
586 		if (ovw
587 		 && n > 0
588 		 && vcost == 0
589 		 && str[0] == '\0'
590 		 && isdigit(TextOf(WANT_CHAR(to_y, from_x))))
591 			ovw = FALSE;
592 #endif
593 		/*
594 		 * If we have no attribute changes, overwrite is cheaper.
595 		 * Note: must suppress this by passing in ovw = FALSE whenever
596 		 * WANT_CHAR would return invalid data.  In particular, this
597 		 * is true between the time a hardware scroll has been done
598 		 * and the time the structure WANT_CHAR would access has been
599 		 * updated.
600 		 */
601 		if (ovw)
602 		{
603 		    int	i;
604 
605 		    for (i = 0; i < n; i++)
606 			if ((WANT_CHAR(to_y, from_x + i) & A_ATTRIBUTES) != CURRENT_ATTR)
607 			{
608 			    ovw = FALSE;
609 			    break;
610 			}
611 		}
612 		if (ovw)
613 		{
614 		    char	*sp;
615 		    int	i;
616 
617 		    sp = str + strlen(str);
618 
619 		    for (i = 0; i < n; i++)
620 			*sp++ = WANT_CHAR(to_y, from_x + i);
621 		    *sp = '\0';
622 		    lhcost += n * SP->_char_padding;
623 		}
624 		else
625 #endif /* defined(REAL_ATTR) && defined(WANT_CHAR) */
626 		{
627 		    lhcost = repeated_append(lhcost, SP->_cuf1_cost, n, str, cursor_right);
628 		}
629 
630 		if (lhcost < hcost)
631 		{
632 		    if (result)
633 			(void) strcpy(result, str);
634 		    hcost = lhcost;
635 		}
636 	    }
637 	}
638 	else /* (to_x < from_x) */
639 	{
640 	    n = from_x - to_x;
641 
642 	    if (parm_left_cursor && SP->_cub_cost < hcost)
643 	    {
644 		if (result)
645 		    (void) strcpy(result, tparm(parm_left_cursor, n));
646 		hcost = SP->_cub_cost;
647 	    }
648 
649 	    if (cursor_left)
650 	    {
651 		int	lhcost = 0;
652 
653 		str[0] = '\0';
654 
655 #if USE_HARD_TABS
656 		if (init_tabs > 0 && back_tab)
657 		{
658 		    int	nxt, fr;
659 
660 		    for (fr = from_x; (nxt = LASTTAB(fr)) >= to_x; fr = nxt)
661 		    {
662 			lhcost = repeated_append(lhcost, SP->_cbt_cost, 1, str, back_tab);
663 			if (lhcost == INFINITY)
664 				break;
665 		    }
666 
667 		    n = fr - to_x;
668 		}
669 #endif /* USE_HARD_TABS */
670 
671 		lhcost = repeated_append(lhcost, SP->_cub1_cost, n, str, cursor_left);
672 
673 		if (lhcost < hcost)
674 		{
675 		    if (result)
676 			(void) strcpy(result, str);
677 		    hcost = lhcost;
678 		}
679 	    }
680 	}
681 
682 	if (hcost == INFINITY)
683 	    return(INFINITY);
684     }
685 
686     return(vcost + hcost);
687 }
688 #endif /* !NO_OPTIMIZE */
689 
690 /*
691  * With the machinery set up above, it's conceivable that
692  * onscreen_mvcur could be modified into a recursive function that does
693  * an alpha-beta search of motion space, as though it were a chess
694  * move tree, with the weight function being boolean and the search
695  * depth equated to length of string.  However, this would jack up the
696  * computation cost a lot, especially on terminals without a cup
697  * capability constraining the search tree depth.  So we settle for
698  * the simpler method below.
699  */
700 
701 static inline int
702 onscreen_mvcur(int yold,int xold,int ynew,int xnew, bool ovw)
703 /* onscreen move from (yold, xold) to (ynew, xnew) */
704 {
705     char	use[OPT_SIZE], *sp;
706     int		tactic = 0, newcost, usecost = INFINITY;
707 
708 #if defined(MAIN) || defined(NCURSES_TEST)
709     struct timeval before, after;
710 
711     gettimeofday(&before, NULL);
712 #endif /* MAIN */
713 
714     /* tactic #0: use direct cursor addressing */
715     sp = tparm(SP->_address_cursor, ynew, xnew);
716     if (sp)
717     {
718 	tactic = 0;
719 	(void) strcpy(use, sp);
720 	usecost = SP->_cup_cost;
721 
722 #if defined(TRACE) || defined(NCURSES_TEST)
723 	if (!(_nc_optimize_enable & OPTIMIZE_MVCUR))
724 	    goto nonlocal;
725 #endif /* TRACE */
726 
727 	/*
728 	 * We may be able to tell in advance that the full optimization
729 	 * will probably not be worth its overhead.  Also, don't try to
730 	 * use local movement if the current attribute is anything but
731 	 * A_NORMAL...there are just too many ways this can screw up
732 	 * (like, say, local-movement \n getting mapped to some obscure
733 	 * character because A_ALTCHARSET is on).
734 	 */
735 	if (yold == -1 || xold == -1 || NOT_LOCAL(yold, xold, ynew, xnew))
736 	{
737 #if defined(MAIN) || defined(NCURSES_TEST)
738 	    if (!profiling)
739 	    {
740 		(void) fputs("nonlocal\n", stderr);
741 		goto nonlocal;	/* always run the optimizer if profiling */
742 	    }
743 #else
744 	    goto nonlocal;
745 #endif /* MAIN */
746 	}
747     }
748 
749 #ifndef NO_OPTIMIZE
750     /* tactic #1: use local movement */
751     if (yold != -1 && xold != -1
752 		&& ((newcost=relative_move(NULL, yold, xold, ynew, xnew, ovw))!=INFINITY)
753 		&& newcost < usecost)
754     {
755 	tactic = 1;
756 	usecost = newcost;
757     }
758 
759     /* tactic #2: use carriage-return + local movement */
760     if (yold != -1 && carriage_return
761 		&& ((newcost=relative_move(NULL, yold,0,ynew,xnew, ovw)) != INFINITY)
762 		&& SP->_cr_cost + newcost < usecost)
763     {
764 	tactic = 2;
765 	usecost = SP->_cr_cost + newcost;
766     }
767 
768     /* tactic #3: use home-cursor + local movement */
769     if (cursor_home
770 	&& ((newcost=relative_move(NULL, 0, 0, ynew, xnew, ovw)) != INFINITY)
771 	&& SP->_home_cost + newcost < usecost)
772     {
773 	tactic = 3;
774 	usecost = SP->_home_cost + newcost;
775     }
776 
777     /* tactic #4: use home-down + local movement */
778     if (cursor_to_ll
779 	&& ((newcost=relative_move(NULL, screen_lines-1, 0, ynew, xnew, ovw)) != INFINITY)
780 	&& SP->_ll_cost + newcost < usecost)
781     {
782 	tactic = 4;
783 	usecost = SP->_ll_cost + newcost;
784     }
785 
786     /*
787      * tactic #5: use left margin for wrap to right-hand side,
788      * unless strange wrap behavior indicated by xenl might hose us.
789      */
790     if (auto_left_margin && !eat_newline_glitch
791 	&& yold > 0 && cursor_left
792 	&& ((newcost=relative_move(NULL, yold-1, screen_columns-1, ynew, xnew, ovw)) != INFINITY)
793 	&& SP->_cr_cost + SP->_cub1_cost + newcost + newcost < usecost)
794     {
795 	tactic = 5;
796 	usecost = SP->_cr_cost + SP->_cub1_cost + newcost;
797     }
798 
799     /*
800      * These cases are ordered by estimated relative frequency.
801      */
802     if (tactic)
803     {
804 	if (tactic == 1)
805 	    (void) relative_move(use, yold, xold, ynew, xnew, ovw);
806 	else if (tactic == 2)
807 	{
808 	    (void) strcpy(use, carriage_return);
809 	    (void) relative_move(use + SP->_carriage_return_length,
810 				 yold,0,ynew,xnew, ovw);
811 	}
812 	else if (tactic == 3)
813 	{
814 	    (void) strcpy(use, cursor_home);
815 	    (void) relative_move(use + SP->_cursor_home_length,
816 				 0, 0, ynew, xnew, ovw);
817 	}
818 	else if (tactic == 4)
819 	{
820 	    (void) strcpy(use, cursor_to_ll);
821 	    (void) relative_move(use + SP->_cursor_to_ll_length,
822 				 screen_lines-1, 0, ynew, xnew, ovw);
823 	}
824 	else /* if (tactic == 5) */
825 	{
826 	    use[0] = '\0';
827 	    if (xold > 0)
828 		(void) strcat(use, carriage_return);
829 	    (void) strcat(use, cursor_left);
830 	    (void) relative_move(use + strlen(use),
831 				 yold-1, screen_columns-1, ynew, xnew, ovw);
832 	}
833     }
834 #endif /* !NO_OPTIMIZE */
835 
836 #if defined(MAIN) || defined(NCURSES_TEST)
837     gettimeofday(&after, NULL);
838     diff = after.tv_usec - before.tv_usec
839 	+ (after.tv_sec - before.tv_sec) * 1000000;
840     if (!profiling)
841 	(void) fprintf(stderr, "onscreen: %d msec, %f 28.8Kbps char-equivalents\n",
842 		       (int)diff, diff/288);
843 #endif /* MAIN */
844 
845  nonlocal:
846     if (usecost != INFINITY)
847     {
848 	TPUTS_TRACE("mvcur");
849 	tputs(use, 1, _nc_outch);
850 	return(OK);
851     }
852     else
853 	return(ERR);
854 }
855 
856 int mvcur(int yold, int xold, int ynew, int xnew)
857 /* optimized cursor move from (yold, xold) to (ynew, xnew) */
858 {
859     TR(TRACE_MOVE, ("mvcur(%d,%d,%d,%d) called", yold, xold, ynew, xnew));
860 
861     if (yold == ynew && xold == xnew)
862 	return(OK);
863 
864     /*
865      * Most work here is rounding for terminal boundaries getting the
866      * column position implied by wraparound or the lack thereof and
867      * rolling up the screen to get ynew on the screen.
868      */
869 
870     if (xnew >= screen_columns)
871     {
872 	ynew += xnew / screen_columns;
873 	xnew %= screen_columns;
874     }
875     if (xold >= screen_columns)
876     {
877 	int	l;
878 
879 	l = (xold + 1) / screen_columns;
880 	yold += l;
881 	if (yold >= screen_lines)
882 		l -= (yold - screen_lines - 1);
883 
884 	while (l > 0) {
885 		if (newline)
886 		{
887 			TPUTS_TRACE("newline");
888 			tputs(newline, 0, _nc_outch);
889 		}
890 		else
891 			putchar('\n');
892 		l--;
893 		if (xold > 0)
894 		{
895 			if (carriage_return)
896 			{
897 				TPUTS_TRACE("carriage_return");
898 				tputs(carriage_return, 0, _nc_outch);
899 			}
900 			else
901 				putchar('\r');
902 			xold = 0;
903 		}
904 	}
905     }
906 
907     if (yold > screen_lines - 1)
908 	yold = screen_lines - 1;
909     if (ynew > screen_lines - 1)
910 	ynew = screen_lines - 1;
911 
912     /* destination location is on screen now */
913     return(onscreen_mvcur(yold, xold, ynew, xnew, TRUE));
914 }
915 
916 #if defined(TRACE) || defined(NCURSES_TEST)
917 int _nc_optimize_enable = OPTIMIZE_ALL;
918 #endif
919 
920 #if defined(MAIN) || defined(NCURSES_TEST)
921 /****************************************************************************
922  *
923  * Movement optimizer test code
924  *
925  ****************************************************************************/
926 
927 #include <tic.h>
928 #include <dump_entry.h>
929 
930 const char *_nc_progname = "mvcur";
931 
932 static unsigned long xmits;
933 
934 int tputs(const char *string, int affcnt GCC_UNUSED, int (*outc)(int) GCC_UNUSED)
935 /* stub tputs() that dumps sequences in a visible form */
936 {
937     if (profiling)
938 	xmits += strlen(string);
939     else
940 	(void) fputs(_nc_visbuf(string), stdout);
941     return(OK);
942 }
943 
944 int putp(const char *string)
945 {
946     return(tputs(string, 1, _nc_outch));
947 }
948 
949 int _nc_outch(int ch)
950 {
951     putc(ch, stdout);
952     return OK;
953 }
954 
955 static char	tname[MAX_ALIAS];
956 
957 static void load_term(void)
958 {
959     (void) setupterm(tname, STDOUT_FILENO, NULL);
960 }
961 
962 static int roll(int n)
963 {
964     int i, j;
965 
966     i = (RAND_MAX / n) * n;
967     while ((j = rand()) >= i)
968 	continue;
969     return (j % n);
970 }
971 
972 int main(int argc GCC_UNUSED, char *argv[] GCC_UNUSED)
973 {
974     (void) strcpy(tname, termname());
975     load_term();
976     _nc_setupscreen(lines, columns, stdout);
977     baudrate();
978 
979     _nc_mvcur_init();
980     NC_BUFFERED(FALSE);
981 
982     (void) puts("The mvcur tester.  Type ? for help");
983 
984     fputs("smcup:", stdout);
985     putchar('\n');
986 
987     for (;;)
988     {
989 	int	fy, fx, ty, tx, n, i;
990 	char	buf[BUFSIZ], capname[BUFSIZ];
991 
992 	(void) fputs("> ", stdout);
993 	(void) fgets(buf, sizeof(buf), stdin);
994 
995 	if (buf[0] == '?')
996 	{
997 (void) puts("?                -- display this help message");
998 (void) puts("fy fx ty tx      -- (4 numbers) display (fy,fx)->(ty,tx) move");
999 (void) puts("s[croll] n t b m -- display scrolling sequence");
1000 (void) printf("r[eload]         -- reload terminal info for %s\n", termname());
1001 (void) puts("l[oad] <term>    -- load terminal info for type <term>");
1002 (void) puts("d[elete] <cap>   -- delete named capability");
1003 (void) puts("i[nspect]        -- display terminal capabilities");
1004 (void) puts("c[ost]           -- dump cursor-optimization cost table");
1005 (void) puts("o[optimize]      -- toggle movement optimization");
1006 (void) puts("t[orture] <num>  -- torture-test with <num> random moves");
1007 (void) puts("q[uit]           -- quit the program");
1008 	}
1009 	else if (sscanf(buf, "%d %d %d %d", &fy, &fx, &ty, &tx) == 4)
1010 	{
1011 	    struct timeval before, after;
1012 
1013 	    putchar('"');
1014 
1015 	    gettimeofday(&before, NULL);
1016 	    mvcur(fy, fx, ty, tx);
1017 	    gettimeofday(&after, NULL);
1018 
1019 	    printf("\" (%ld msec)\n",
1020 		(long)(after.tv_usec - before.tv_usec + (after.tv_sec - before.tv_sec) * 1000000));
1021 	}
1022 	else if (sscanf(buf, "s %d %d %d %d", &fy, &fx, &ty, &tx) == 4)
1023 	{
1024 	    struct timeval before, after;
1025 
1026 	    putchar('"');
1027 
1028 	    gettimeofday(&before, NULL);
1029 	    _nc_scrolln(fy, fx, ty, tx);
1030 	    gettimeofday(&after, NULL);
1031 
1032 	    printf("\" (%ld msec)\n",
1033 		(long)(after.tv_usec - before.tv_usec + (after.tv_sec - before.tv_sec) * 1000000));
1034 	}
1035 	else if (buf[0] == 'r')
1036 	{
1037 	    (void) strcpy(tname, termname());
1038 	    load_term();
1039 	}
1040 	else if (sscanf(buf, "l %s", tname) == 1)
1041 	{
1042 	    load_term();
1043 	}
1044 	else if (sscanf(buf, "d %s", capname) == 1)
1045 	{
1046 	    struct name_table_entry const	*np = _nc_find_entry(capname,
1047 							 _nc_info_hash_table);
1048 
1049 	    if (np == NULL)
1050 		(void) printf("No such capability as \"%s\"\n", capname);
1051 	    else
1052 	    {
1053 		switch(np->nte_type)
1054 		{
1055 		case BOOLEAN:
1056 		    cur_term->type.Booleans[np->nte_index] = FALSE;
1057 		    (void) printf("Boolean capability `%s' (%d) turned off.\n",
1058 				  np->nte_name, np->nte_index);
1059 		    break;
1060 
1061 		case NUMBER:
1062 		    cur_term->type.Numbers[np->nte_index] = -1;
1063 		    (void) printf("Number capability `%s' (%d) set to -1.\n",
1064 				  np->nte_name, np->nte_index);
1065 		    break;
1066 
1067 		case STRING:
1068 		    cur_term->type.Strings[np->nte_index] = (char *)NULL;
1069 		    (void) printf("String capability `%s' (%d) deleted.\n",
1070 				  np->nte_name, np->nte_index);
1071 		    break;
1072 		}
1073 	    }
1074 	}
1075 	else if (buf[0] == 'i')
1076 	{
1077 	     dump_init((char *)NULL, F_TERMINFO, S_TERMINFO, 70, 0, FALSE);
1078 	     dump_entry(&cur_term->type, FALSE, TRUE, 0);
1079 	     putchar('\n');
1080 	}
1081 	else if (buf[0] == 'o')
1082 	{
1083 	     if (_nc_optimize_enable & OPTIMIZE_MVCUR)
1084 	     {
1085 		 _nc_optimize_enable &=~ OPTIMIZE_MVCUR;
1086 		 (void) puts("Optimization is now off.");
1087 	     }
1088 	     else
1089 	     {
1090 		 _nc_optimize_enable |= OPTIMIZE_MVCUR;
1091 		 (void) puts("Optimization is now on.");
1092 	     }
1093 	}
1094 	/*
1095 	 * You can use the `t' test to profile and tune the movement
1096 	 * optimizer.  Use iteration values in three digits or more.
1097 	 * At above 5000 iterations the profile timing averages are stable
1098 	 * to within a millisecond or three.
1099 	 *
1100 	 * The `overhead' field of the report will help you pick a
1101 	 * COMPUTE_OVERHEAD figure appropriate for your processor and
1102 	 * expected line speed.  The `total estimated time' is
1103 	 * computation time plus a character-transmission time
1104 	 * estimate computed from the number of transmits and the baud
1105 	 * rate.
1106 	 *
1107 	 * Use this together with the `o' command to get a read on the
1108 	 * optimizer's effectiveness.  Compare the total estimated times
1109 	 * for `t' runs of the same length in both optimized and un-optimized
1110 	 * modes.  As long as the optimized times are less, the optimizer
1111 	 * is winning.
1112 	 */
1113 	else if (sscanf(buf, "t %d", &n) == 1)
1114 	{
1115 	    float cumtime = 0, perchar;
1116 	    int speeds[] = {2400, 9600, 14400, 19200, 28800, 38400, 0};
1117 
1118 	    srand((unsigned)(getpid() + time((time_t *)0)));
1119 	    profiling = TRUE;
1120 	    xmits = 0;
1121 	    for (i = 0; i < n; i++)
1122 	    {
1123 		/*
1124 		 * This does a move test between two random locations,
1125 		 * Random moves probably short-change the optimizer,
1126 		 * which will work better on the short moves probably
1127 		 * typical of doupdate()'s usage pattern.  Still,
1128 		 * until we have better data...
1129 		 */
1130 #ifdef FIND_COREDUMP
1131 		int from_y = roll(lines);
1132 		int to_y = roll(lines);
1133 		int from_x = roll(columns);
1134 		int to_x = roll(columns);
1135 
1136 		printf("(%d,%d) -> (%d,%d)\n", from_y, from_x, to_y, to_x);
1137 		mvcur(from_y, from_x, to_y, to_x);
1138 #else
1139 		mvcur(roll(lines), roll(columns), roll(lines), roll(columns));
1140 #endif /* FIND_COREDUMP */
1141 		if (diff)
1142 		    cumtime += diff;
1143 	    }
1144 	    profiling = FALSE;
1145 
1146 	    /*
1147 	     * Average milliseconds per character optimization time.
1148 	     * This is the key figure to watch when tuning the optimizer.
1149 	     */
1150 	    perchar = cumtime / n;
1151 
1152 	    (void) printf("%d moves (%ld chars) in %d msec, %f msec each:\n",
1153 			  n, xmits, (int)cumtime, perchar);
1154 
1155 	    for (i = 0; speeds[i]; i++)
1156 	    {
1157 		/*
1158 		 * Total estimated time for the moves, computation and
1159 		 * transmission both. Transmission time is an estimate
1160 		 * assuming 9 bits/char, 8 bits + 1 stop bit.
1161 		 */
1162 		float totalest = cumtime + xmits * 9 * 1e6 / speeds[i];
1163 
1164 		/*
1165 		 * Per-character optimization overhead in character transmits
1166 		 * at the current speed.  Round this to the nearest integer
1167 		 * to figure COMPUTE_OVERHEAD for the speed.
1168 		 */
1169 		float overhead = speeds[i] * perchar / 1e6;
1170 
1171 		(void) printf("%6d bps: %3.2f char-xmits overhead; total estimated time %15.2f\n",
1172 			      speeds[i], overhead, totalest);
1173 	    }
1174 	}
1175 	else if (buf[0] == 'c')
1176 	{
1177 	    (void) printf("char padding: %d\n", SP->_char_padding);
1178 	    (void) printf("cr cost: %d\n", SP->_cr_cost);
1179 	    (void) printf("cup cost: %d\n", SP->_cup_cost);
1180 	    (void) printf("home cost: %d\n", SP->_home_cost);
1181 	    (void) printf("ll cost: %d\n", SP->_ll_cost);
1182 #if USE_HARD_TABS
1183 	    (void) printf("ht cost: %d\n", SP->_ht_cost);
1184 	    (void) printf("cbt cost: %d\n", SP->_cbt_cost);
1185 #endif /* USE_HARD_TABS */
1186 	    (void) printf("cub1 cost: %d\n", SP->_cub1_cost);
1187 	    (void) printf("cuf1 cost: %d\n", SP->_cuf1_cost);
1188 	    (void) printf("cud1 cost: %d\n", SP->_cud1_cost);
1189 	    (void) printf("cuu1 cost: %d\n", SP->_cuu1_cost);
1190 	    (void) printf("cub cost: %d\n", SP->_cub_cost);
1191 	    (void) printf("cuf cost: %d\n", SP->_cuf_cost);
1192 	    (void) printf("cud cost: %d\n", SP->_cud_cost);
1193 	    (void) printf("cuu cost: %d\n", SP->_cuu_cost);
1194 	    (void) printf("hpa cost: %d\n", SP->_hpa_cost);
1195 	    (void) printf("vpa cost: %d\n", SP->_vpa_cost);
1196 	}
1197 	else if (buf[0] == 'x' || buf[0] == 'q')
1198 	    break;
1199 	else
1200 	    (void) puts("Invalid command.");
1201     }
1202 
1203     (void) fputs("rmcup:", stdout);
1204     _nc_mvcur_wrap();
1205     putchar('\n');
1206 
1207     return(0);
1208 }
1209 
1210 #endif /* MAIN */
1211 
1212 /* lib_mvcur.c ends here */
1213