1/****************************************************************************
2 * Copyright (c) 1998-2004,2005 Free Software Foundation, Inc.              *
3 *                                                                          *
4 * Permission is hereby granted, free of charge, to any person obtaining a  *
5 * copy of this software and associated documentation files (the            *
6 * "Software"), to deal in the Software without restriction, including      *
7 * without limitation the rights to use, copy, modify, merge, publish,      *
8 * distribute, distribute with modifications, sublicense, and/or sell       *
9 * copies of the Software, and to permit persons to whom the Software is    *
10 * furnished to do so, subject to the following conditions:                 *
11 *                                                                          *
12 * The above copyright notice and this permission notice shall be included  *
13 * in all copies or substantial portions of the Software.                   *
14 *                                                                          *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
16 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
18 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
19 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
20 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
21 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
22 *                                                                          *
23 * Except as contained in this notice, the name(s) of the above copyright   *
24 * holders shall not be used in advertising or otherwise to promote the     *
25 * sale, use or other dealings in this Software without prior written       *
26 * authorization.                                                           *
27 ****************************************************************************/
28
29/****************************************************************************
30 *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
31 *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
32 *     and: Thomas E. Dickey                        1996-on                 *
33 ****************************************************************************/
34
35/*
36**	lib_mvcur.c
37**
38**	The routines for moving the physical cursor and scrolling:
39**
40**		void _nc_mvcur_init(void)
41**
42**		void _nc_mvcur_resume(void)
43**
44**		int mvcur(int old_y, int old_x, int new_y, int new_x)
45**
46**		void _nc_mvcur_wrap(void)
47**
48** Comparisons with older movement optimizers:
49**    SVr3 curses mvcur() can't use cursor_to_ll or auto_left_margin.
50**    4.4BSD curses can't use cuu/cud/cuf/cub/hpa/vpa/tab/cbt for local
51** motions.  It doesn't use tactics based on auto_left_margin.  Weirdly
52** enough, it doesn't use its own hardware-scrolling routine to scroll up
53** destination lines for out-of-bounds addresses!
54**    old ncurses optimizer: less accurate cost computations (in fact,
55** it was broken and had to be commented out!).
56**
57** Compile with -DMAIN to build an interactive tester/timer for the movement
58** optimizer.  You can use it to investigate the optimizer's behavior.
59** You can also use it for tuning the formulas used to determine whether
60** or not full optimization is attempted.
61**
62** This code has a nasty tendency to find bugs in terminfo entries, because it
63** exercises the non-cup movement capabilities heavily.  If you think you've
64** found a bug, try deleting subsets of the following capabilities (arranged
65** in decreasing order of suspiciousness): it, tab, cbt, hpa, vpa, cuu, cud,
66** cuf, cub, cuu1, cud1, cuf1, cub1.  It may be that one or more are wrong.
67**
68** Note: you should expect this code to look like a resource hog in a profile.
69** That's because it does a lot of I/O, through the tputs() calls.  The I/O
70** cost swamps the computation overhead (and as machines get faster, this
71** will become even more true).  Comments in the test exerciser at the end
72** go into detail about tuning and how you can gauge the optimizer's
73** effectiveness.
74**/
75
76/****************************************************************************
77 *
78 * Constants and macros for optimizer tuning.
79 *
80 ****************************************************************************/
81
82/*
83 * The average overhead of a full optimization computation in character
84 * transmission times.  If it's too high, the algorithm will be a bit
85 * over-biased toward using cup rather than local motions; if it's too
86 * low, the algorithm may spend more time than is strictly optimal
87 * looking for non-cup motions.  Profile the optimizer using the `t'
88 * command of the exerciser (see below), and round to the nearest integer.
89 *
90 * Yes, I (esr) thought about computing expected overhead dynamically, say
91 * by derivation from a running average of optimizer times.  But the
92 * whole point of this optimization is to *decrease* the frequency of
93 * system calls. :-)
94 */
95#define COMPUTE_OVERHEAD	1	/* I use a 90MHz Pentium @ 9.6Kbps */
96
97/*
98 * LONG_DIST is the distance we consider to be just as costly to move over as a
99 * cup sequence is to emit.  In other words, it's the length of a cup sequence
100 * adjusted for average computation overhead.  The magic number is the length
101 * of "\033[yy;xxH", the typical cup sequence these days.
102 */
103#define LONG_DIST		(8 - COMPUTE_OVERHEAD)
104
105/*
106 * Tell whether a motion is optimizable by local motions.  Needs to be cheap to
107 * compute. In general, all the fast moves go to either the right or left edge
108 * of the screen.  So any motion to a location that is (a) further away than
109 * LONG_DIST and (b) further inward from the right or left edge than LONG_DIST,
110 * we'll consider nonlocal.
111 */
112#define NOT_LOCAL(fy, fx, ty, tx)	((tx > LONG_DIST) \
113 		 && (tx < screen_columns - 1 - LONG_DIST) \
114		 && (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
158MODULE_ID("$Id: lib_mvcur.c,v 1.103 2005/06/11 19:30:15 tom Exp $")
159
160#define WANT_CHAR(y, x)	SP->_newscr->_line[y].text[x]	/* desired state */
161#define BAUDRATE	cur_term->_baudrate	/* bits per second */
162
163#if defined(MAIN) || defined(NCURSES_TEST)
164#include <sys/time.h>
165
166static bool profiling = FALSE;
167static float diff;
168#endif /* MAIN */
169
170#define OPT_SIZE 512
171
172static int normalized_cost(const char *const cap, int affcnt);
173
174/****************************************************************************
175 *
176 * Initialization/wrapup (including cost pre-computation)
177 *
178 ****************************************************************************/
179
180#ifdef TRACE
181static int
182trace_cost_of(const char *capname, const char *cap, int affcnt)
183{
184    int result = _nc_msec_cost(cap, affcnt);
185    TR(TRACE_CHARPUT | TRACE_MOVE,
186       ("CostOf %s %d %s", capname, result, _nc_visbuf(cap)));
187    return result;
188}
189#define CostOf(cap,affcnt) trace_cost_of(#cap,cap,affcnt);
190
191static int
192trace_normalized_cost(const char *capname, const char *cap, int affcnt)
193{
194    int result = normalized_cost(cap, affcnt);
195    TR(TRACE_CHARPUT | TRACE_MOVE,
196       ("NormalizedCost %s %d %s", capname, result, _nc_visbuf(cap)));
197    return result;
198}
199#define NormalizedCost(cap,affcnt) trace_normalized_cost(#cap,cap,affcnt);
200
201#else
202
203#define CostOf(cap,affcnt) _nc_msec_cost(cap,affcnt);
204#define NormalizedCost(cap,affcnt) normalized_cost(cap,affcnt);
205
206#endif
207
208NCURSES_EXPORT(int)
209_nc_msec_cost(const char *const cap, int affcnt)
210/* compute the cost of a given operation */
211{
212    if (cap == 0)
213	return (INFINITY);
214    else {
215	const char *cp;
216	float cum_cost = 0.0;
217
218	for (cp = cap; *cp; cp++) {
219	    /* extract padding, either mandatory or required */
220	    if (cp[0] == '$' && cp[1] == '<' && strchr(cp, '>')) {
221		float number = 0.0;
222
223		for (cp += 2; *cp != '>'; cp++) {
224		    if (isdigit(UChar(*cp)))
225			number = number * 10 + (*cp - '0');
226		    else if (*cp == '*')
227			number *= affcnt;
228		    else if (*cp == '.' && (*++cp != '>') && isdigit(UChar(*cp)))
229			number += (*cp - '0') / 10.0;
230		}
231
232#if NCURSES_NO_PADDING
233		if (!(SP->_no_padding))
234#endif
235		    cum_cost += number * 10;
236	    } else
237		cum_cost += SP->_char_padding;
238	}
239
240	return ((int) cum_cost);
241    }
242}
243
244static int
245normalized_cost(const char *const cap, int affcnt)
246/* compute the effective character-count for an operation (round up) */
247{
248    int cost = _nc_msec_cost(cap, affcnt);
249    if (cost != INFINITY)
250	cost = (cost + SP->_char_padding - 1) / SP->_char_padding;
251    return cost;
252}
253
254static void
255reset_scroll_region(void)
256/* Set the scroll-region to a known state (the default) */
257{
258    if (change_scroll_region) {
259	TPUTS_TRACE("change_scroll_region");
260	putp(tparm(change_scroll_region, 0, screen_lines - 1));
261    }
262}
263
264NCURSES_EXPORT(void)
265_nc_mvcur_resume(void)
266/* what to do at initialization time and after each shellout */
267{
268    /* initialize screen for cursor access */
269    if (enter_ca_mode) {
270	TPUTS_TRACE("enter_ca_mode");
271	putp(enter_ca_mode);
272    }
273
274    /*
275     * Doing this here rather than in _nc_mvcur_wrap() ensures that
276     * ncurses programs will see a reset scroll region even if a
277     * program that messed with it died ungracefully.
278     *
279     * This also undoes the effects of terminal init strings that assume
280     * they know the screen size.  This is useful when you're running
281     * a vt100 emulation through xterm.
282     */
283    reset_scroll_region();
284    SP->_cursrow = SP->_curscol = -1;
285
286    /* restore cursor shape */
287    if (SP->_cursor != -1) {
288	int cursor = SP->_cursor;
289	SP->_cursor = -1;
290	curs_set(cursor);
291    }
292}
293
294NCURSES_EXPORT(void)
295_nc_mvcur_init(void)
296/* initialize the cost structure */
297{
298    if (isatty(fileno(SP->_ofp)))
299	SP->_char_padding = ((BAUDBYTE * 1000 * 10)
300			     / (BAUDRATE > 0 ? BAUDRATE : 9600));
301    else
302	SP->_char_padding = 1;	/* must be nonzero */
303    if (SP->_char_padding <= 0)
304	SP->_char_padding = 1;	/* must be nonzero */
305    TR(TRACE_CHARPUT | TRACE_MOVE, ("char_padding %d msecs", SP->_char_padding));
306
307    /* non-parameterized local-motion strings */
308    SP->_cr_cost = CostOf(carriage_return, 0);
309    SP->_home_cost = CostOf(cursor_home, 0);
310    SP->_ll_cost = CostOf(cursor_to_ll, 0);
311#if USE_HARD_TABS
312    SP->_ht_cost = CostOf(tab, 0);
313    SP->_cbt_cost = CostOf(back_tab, 0);
314#endif /* USE_HARD_TABS */
315    SP->_cub1_cost = CostOf(cursor_left, 0);
316    SP->_cuf1_cost = CostOf(cursor_right, 0);
317    SP->_cud1_cost = CostOf(cursor_down, 0);
318    SP->_cuu1_cost = CostOf(cursor_up, 0);
319
320    SP->_smir_cost = CostOf(enter_insert_mode, 0);
321    SP->_rmir_cost = CostOf(exit_insert_mode, 0);
322    SP->_ip_cost = 0;
323    if (insert_padding) {
324	SP->_ip_cost = CostOf(insert_padding, 0);
325    }
326
327    /*
328     * Assumption: if the terminal has memory_relative addressing, the
329     * initialization strings or smcup will set single-page mode so we
330     * can treat it like absolute screen addressing.  This seems to be true
331     * for all cursor_mem_address terminal types in the terminfo database.
332     */
333    SP->_address_cursor = cursor_address ? cursor_address : cursor_mem_address;
334
335    /*
336     * Parametrized local-motion strings.  This static cost computation
337     * depends on the following assumptions:
338     *
339     * (1) They never have * padding.  In the entire master terminfo database
340     *     as of March 1995, only the obsolete Zenith Z-100 pc violates this.
341     *     (Proportional padding is found mainly in insert, delete and scroll
342     *     capabilities).
343     *
344     * (2) The average case of cup has two two-digit parameters.  Strictly,
345     *     the average case for a 24 * 80 screen has ((10*10*(1 + 1)) +
346     *     (14*10*(1 + 2)) + (10*70*(2 + 1)) + (14*70*4)) / (24*80) = 3.458
347     *     digits of parameters.  On a 25x80 screen the average is 3.6197.
348     *     On larger screens the value gets much closer to 4.
349     *
350     * (3) The average case of cub/cuf/hpa/ech/rep has 2 digits of parameters
351     *     (strictly, (((10 * 1) + (70 * 2)) / 80) = 1.8750).
352     *
353     * (4) The average case of cud/cuu/vpa has 2 digits of parameters
354     *     (strictly, (((10 * 1) + (14 * 2)) / 24) = 1.5833).
355     *
356     * All these averages depend on the assumption that all parameter values
357     * are equally probable.
358     */
359    SP->_cup_cost = CostOf(tparm(SP->_address_cursor, 23, 23), 1);
360    SP->_cub_cost = CostOf(tparm(parm_left_cursor, 23), 1);
361    SP->_cuf_cost = CostOf(tparm(parm_right_cursor, 23), 1);
362    SP->_cud_cost = CostOf(tparm(parm_down_cursor, 23), 1);
363    SP->_cuu_cost = CostOf(tparm(parm_up_cursor, 23), 1);
364    SP->_hpa_cost = CostOf(tparm(column_address, 23), 1);
365    SP->_vpa_cost = CostOf(tparm(row_address, 23), 1);
366
367    /* non-parameterized screen-update strings */
368    SP->_ed_cost = NormalizedCost(clr_eos, 1);
369    SP->_el_cost = NormalizedCost(clr_eol, 1);
370    SP->_el1_cost = NormalizedCost(clr_bol, 1);
371    SP->_dch1_cost = NormalizedCost(delete_character, 1);
372    SP->_ich1_cost = NormalizedCost(insert_character, 1);
373
374    /*
375     * If this is a bce-terminal, we want to bias the choice so we use clr_eol
376     * rather than spaces at the end of a line.
377     */
378    if (back_color_erase)
379	SP->_el_cost = 0;
380
381    /* parameterized screen-update strings */
382    SP->_dch_cost = NormalizedCost(tparm(parm_dch, 23), 1);
383    SP->_ich_cost = NormalizedCost(tparm(parm_ich, 23), 1);
384    SP->_ech_cost = NormalizedCost(tparm(erase_chars, 23), 1);
385    SP->_rep_cost = NormalizedCost(tparm(repeat_char, ' ', 23), 1);
386
387    SP->_cup_ch_cost = NormalizedCost(tparm(SP->_address_cursor, 23, 23), 1);
388    SP->_hpa_ch_cost = NormalizedCost(tparm(column_address, 23), 1);
389    SP->_cuf_ch_cost = NormalizedCost(tparm(parm_right_cursor, 23), 1);
390    SP->_inline_cost = min(SP->_cup_ch_cost,
391			   min(SP->_hpa_ch_cost,
392			       SP->_cuf_ch_cost));
393
394    /*
395     * If save_cursor is used within enter_ca_mode, we should not use it for
396     * scrolling optimization, since the corresponding restore_cursor is not
397     * nested on the various terminals (vt100, xterm, etc.) which use this
398     * feature.
399     */
400    if (save_cursor != 0
401	&& enter_ca_mode != 0
402	&& strstr(enter_ca_mode, save_cursor) != 0) {
403	T(("...suppressed sc/rc capability due to conflict with smcup/rmcup"));
404	save_cursor = 0;
405	restore_cursor = 0;
406    }
407
408    /*
409     * A different, possibly better way to arrange this would be to set
410     * SP->_endwin = TRUE at window initialization time and let this be
411     * called by doupdate's return-from-shellout code.
412     */
413    _nc_mvcur_resume();
414}
415
416NCURSES_EXPORT(void)
417_nc_mvcur_wrap(void)
418/* wrap up cursor-addressing mode */
419{
420    /* leave cursor at screen bottom */
421    mvcur(-1, -1, screen_lines - 1, 0);
422
423    /* set cursor to normal mode */
424    if (SP->_cursor != -1)
425	curs_set(1);
426
427    if (exit_ca_mode) {
428	TPUTS_TRACE("exit_ca_mode");
429	putp(exit_ca_mode);
430    }
431    /*
432     * Reset terminal's tab counter.  There's a long-time bug that
433     * if you exit a "curses" program such as vi or more, tab
434     * forward, and then backspace, the cursor doesn't go to the
435     * right place.  The problem is that the kernel counts the
436     * escape sequences that reset things as column positions.
437     * Utter a \r to reset this invisibly.
438     */
439    _nc_outch('\r');
440}
441
442/****************************************************************************
443 *
444 * Optimized cursor movement
445 *
446 ****************************************************************************/
447
448/*
449 * Perform repeated-append, returning cost
450 */
451static inline int
452repeated_append(string_desc * target, int total, int num, int repeat, const char *src)
453{
454    size_t need = repeat * strlen(src);
455
456    if (need < target->s_size) {
457	while (repeat-- > 0) {
458	    if (_nc_safe_strcat(target, src)) {
459		total += num;
460	    } else {
461		total = INFINITY;
462		break;
463	    }
464	}
465    } else {
466	total = INFINITY;
467    }
468    return total;
469}
470
471#ifndef NO_OPTIMIZE
472#define NEXTTAB(fr)	(fr + init_tabs - (fr % init_tabs))
473
474/*
475 * Assume back_tab (CBT) does not wrap backwards at the left margin, return
476 * a negative value at that point to simplify the loop.
477 */
478#define LASTTAB(fr)	((fr > 0) ? ((fr - 1) / init_tabs) * init_tabs : -1)
479
480static int
481relative_move(string_desc * target, int from_y, int from_x, int to_y, int
482	      to_x, bool ovw)
483/* move via local motions (cuu/cuu1/cud/cud1/cub1/cub/cuf1/cuf/vpa/hpa) */
484{
485    string_desc save;
486    int n, vcost = 0, hcost = 0;
487
488    (void) _nc_str_copy(&save, target);
489
490    if (to_y != from_y) {
491	vcost = INFINITY;
492
493	if (row_address != 0
494	    && _nc_safe_strcat(target, tparm(row_address, to_y))) {
495	    vcost = SP->_vpa_cost;
496	}
497
498	if (to_y > from_y) {
499	    n = (to_y - from_y);
500
501	    if (parm_down_cursor
502		&& SP->_cud_cost < vcost
503		&& _nc_safe_strcat(_nc_str_copy(target, &save),
504				   tparm(parm_down_cursor, n))) {
505		vcost = SP->_cud_cost;
506	    }
507
508	    if (cursor_down
509		&& (*cursor_down != '\n' || SP->_nl)
510		&& (n * SP->_cud1_cost < vcost)) {
511		vcost = repeated_append(_nc_str_copy(target, &save), 0,
512					SP->_cud1_cost, n, cursor_down);
513	    }
514	} else {		/* (to_y < from_y) */
515	    n = (from_y - to_y);
516
517	    if (parm_up_cursor
518		&& SP->_cuu_cost < vcost
519		&& _nc_safe_strcat(_nc_str_copy(target, &save),
520				   tparm(parm_up_cursor, n))) {
521		vcost = SP->_cuu_cost;
522	    }
523
524	    if (cursor_up && (n * SP->_cuu1_cost < vcost)) {
525		vcost = repeated_append(_nc_str_copy(target, &save), 0,
526					SP->_cuu1_cost, n, cursor_up);
527	    }
528	}
529
530	if (vcost == INFINITY)
531	    return (INFINITY);
532    }
533
534    save = *target;
535
536    if (to_x != from_x) {
537	char str[OPT_SIZE];
538	string_desc check;
539
540	hcost = INFINITY;
541
542	if (column_address
543	    && _nc_safe_strcat(_nc_str_copy(target, &save),
544			       tparm(column_address, to_x))) {
545	    hcost = SP->_hpa_cost;
546	}
547
548	if (to_x > from_x) {
549	    n = to_x - from_x;
550
551	    if (parm_right_cursor
552		&& SP->_cuf_cost < hcost
553		&& _nc_safe_strcat(_nc_str_copy(target, &save),
554				   tparm(parm_right_cursor, n))) {
555		hcost = SP->_cuf_cost;
556	    }
557
558	    if (cursor_right) {
559		int lhcost = 0;
560
561		(void) _nc_str_init(&check, str, sizeof(str));
562
563#if USE_HARD_TABS
564		/* use hard tabs, if we have them, to do as much as possible */
565		if (init_tabs > 0 && tab) {
566		    int nxt, fr;
567
568		    for (fr = from_x; (nxt = NEXTTAB(fr)) <= to_x; fr = nxt) {
569			lhcost = repeated_append(&check, lhcost,
570						 SP->_ht_cost, 1, tab);
571			if (lhcost == INFINITY)
572			    break;
573		    }
574
575		    n = to_x - fr;
576		    from_x = fr;
577		}
578#endif /* USE_HARD_TABS */
579
580		if (n <= 0 || n >= (int) check.s_size)
581		    ovw = FALSE;
582#if BSD_TPUTS
583		/*
584		 * If we're allowing BSD-style padding in tputs, don't generate
585		 * a string with a leading digit.  Otherwise, that will be
586		 * interpreted as a padding value rather than sent to the
587		 * screen.
588		 */
589		if (ovw
590		    && n > 0
591		    && n < (int) check.s_size
592		    && vcost == 0
593		    && str[0] == '\0') {
594		    int wanted = CharOf(WANT_CHAR(to_y, from_x));
595		    if (is8bits(wanted) && isdigit(wanted))
596			ovw = FALSE;
597		}
598#endif
599		/*
600		 * If we have no attribute changes, overwrite is cheaper.
601		 * Note: must suppress this by passing in ovw = FALSE whenever
602		 * WANT_CHAR would return invalid data.  In particular, this
603		 * is true between the time a hardware scroll has been done
604		 * and the time the structure WANT_CHAR would access has been
605		 * updated.
606		 */
607		if (ovw) {
608		    int i;
609
610		    for (i = 0; i < n; i++) {
611			NCURSES_CH_T ch = WANT_CHAR(to_y, from_x + i);
612			if (!SameAttrOf(ch, SCREEN_ATTRS(SP))
613#if USE_WIDEC_SUPPORT
614			    || !Charable(ch)
615#endif
616			    ) {
617			    ovw = FALSE;
618			    break;
619			}
620		    }
621		}
622		if (ovw) {
623		    int i;
624
625		    for (i = 0; i < n; i++)
626			*check.s_tail++ = CharOf(WANT_CHAR(to_y, from_x + i));
627		    *check.s_tail = '\0';
628		    check.s_size -= n;
629		    lhcost += n * SP->_char_padding;
630		} else {
631		    lhcost = repeated_append(&check, lhcost, SP->_cuf1_cost,
632					     n, cursor_right);
633		}
634
635		if (lhcost < hcost
636		    && _nc_safe_strcat(_nc_str_copy(target, &save), str)) {
637		    hcost = lhcost;
638		}
639	    }
640	} else {		/* (to_x < from_x) */
641	    n = from_x - to_x;
642
643	    if (parm_left_cursor
644		&& SP->_cub_cost < hcost
645		&& _nc_safe_strcat(_nc_str_copy(target, &save),
646				   tparm(parm_left_cursor, n))) {
647		hcost = SP->_cub_cost;
648	    }
649
650	    if (cursor_left) {
651		int lhcost = 0;
652
653		(void) _nc_str_init(&check, str, sizeof(str));
654
655#if USE_HARD_TABS
656		if (init_tabs > 0 && back_tab) {
657		    int nxt, fr;
658
659		    for (fr = from_x; (nxt = LASTTAB(fr)) >= to_x; fr = nxt) {
660			lhcost = repeated_append(&check, lhcost,
661						 SP->_cbt_cost, 1, back_tab);
662			if (lhcost == INFINITY)
663			    break;
664		    }
665
666		    n = fr - to_x;
667		}
668#endif /* USE_HARD_TABS */
669
670		lhcost = repeated_append(&check, lhcost, SP->_cub1_cost, n, cursor_left);
671
672		if (lhcost < hcost
673		    && _nc_safe_strcat(_nc_str_copy(target, &save), str)) {
674		    hcost = lhcost;
675		}
676	    }
677	}
678
679	if (hcost == INFINITY)
680	    return (INFINITY);
681    }
682
683    return (vcost + hcost);
684}
685#endif /* !NO_OPTIMIZE */
686
687/*
688 * With the machinery set up above, it's conceivable that
689 * onscreen_mvcur could be modified into a recursive function that does
690 * an alpha-beta search of motion space, as though it were a chess
691 * move tree, with the weight function being boolean and the search
692 * depth equated to length of string.  However, this would jack up the
693 * computation cost a lot, especially on terminals without a cup
694 * capability constraining the search tree depth.  So we settle for
695 * the simpler method below.
696 */
697
698static inline int
699onscreen_mvcur(int yold, int xold, int ynew, int xnew, bool ovw)
700/* onscreen move from (yold, xold) to (ynew, xnew) */
701{
702    string_desc result;
703    char buffer[OPT_SIZE];
704    int tactic = 0, newcost, usecost = INFINITY;
705    int t5_cr_cost;
706
707#if defined(MAIN) || defined(NCURSES_TEST)
708    struct timeval before, after;
709
710    gettimeofday(&before, NULL);
711#endif /* MAIN */
712
713#define NullResult _nc_str_null(&result, sizeof(buffer))
714#define InitResult _nc_str_init(&result, buffer, sizeof(buffer))
715
716    /* tactic #0: use direct cursor addressing */
717    if (_nc_safe_strcpy(InitResult, tparm(SP->_address_cursor, ynew, xnew))) {
718	tactic = 0;
719	usecost = SP->_cup_cost;
720
721#if defined(TRACE) || defined(NCURSES_TEST)
722	if (!(_nc_optimize_enable & OPTIMIZE_MVCUR))
723	    goto nonlocal;
724#endif /* TRACE */
725
726	/*
727	 * We may be able to tell in advance that the full optimization
728	 * will probably not be worth its overhead.  Also, don't try to
729	 * use local movement if the current attribute is anything but
730	 * A_NORMAL...there are just too many ways this can screw up
731	 * (like, say, local-movement \n getting mapped to some obscure
732	 * character because A_ALTCHARSET is on).
733	 */
734	if (yold == -1 || xold == -1 || NOT_LOCAL(yold, xold, ynew, xnew)) {
735#if defined(MAIN) || defined(NCURSES_TEST)
736	    if (!profiling) {
737		(void) fputs("nonlocal\n", stderr);
738		goto nonlocal;	/* always run the optimizer if profiling */
739	    }
740#else
741	    goto nonlocal;
742#endif /* MAIN */
743	}
744    }
745#ifndef NO_OPTIMIZE
746    /* tactic #1: use local movement */
747    if (yold != -1 && xold != -1
748	&& ((newcost = relative_move(NullResult, yold, xold, ynew, xnew,
749				     ovw)) != INFINITY)
750	&& newcost < usecost) {
751	tactic = 1;
752	usecost = newcost;
753    }
754
755    /* tactic #2: use carriage-return + local movement */
756    if (yold != -1 && carriage_return
757	&& ((newcost = relative_move(NullResult, yold, 0, ynew, xnew, ovw))
758	    != INFINITY)
759	&& SP->_cr_cost + newcost < usecost) {
760	tactic = 2;
761	usecost = SP->_cr_cost + newcost;
762    }
763
764    /* tactic #3: use home-cursor + local movement */
765    if (cursor_home
766	&& ((newcost = relative_move(NullResult, 0, 0, ynew, xnew, ovw)) != INFINITY)
767	&& SP->_home_cost + newcost < usecost) {
768	tactic = 3;
769	usecost = SP->_home_cost + newcost;
770    }
771
772    /* tactic #4: use home-down + local movement */
773    if (cursor_to_ll
774	&& ((newcost = relative_move(NullResult, screen_lines - 1, 0, ynew,
775				     xnew, ovw)) != INFINITY)
776	&& SP->_ll_cost + newcost < usecost) {
777	tactic = 4;
778	usecost = SP->_ll_cost + newcost;
779    }
780
781    /*
782     * tactic #5: use left margin for wrap to right-hand side,
783     * unless strange wrap behavior indicated by xenl might hose us.
784     */
785    t5_cr_cost = (xold > 0 ? SP->_cr_cost : 0);
786    if (auto_left_margin && !eat_newline_glitch
787	&& yold > 0 && cursor_left
788	&& ((newcost = relative_move(NullResult, yold - 1, screen_columns -
789				     1, ynew, xnew, ovw)) != INFINITY)
790	&& t5_cr_cost + SP->_cub1_cost + newcost < usecost) {
791	tactic = 5;
792	usecost = t5_cr_cost + SP->_cub1_cost + newcost;
793    }
794
795    /*
796     * These cases are ordered by estimated relative frequency.
797     */
798    if (tactic)
799	InitResult;
800    switch (tactic) {
801    case 1:
802	(void) relative_move(&result, yold, xold, ynew, xnew, ovw);
803	break;
804    case 2:
805	(void) _nc_safe_strcpy(&result, carriage_return);
806	(void) relative_move(&result, yold, 0, ynew, xnew, ovw);
807	break;
808    case 3:
809	(void) _nc_safe_strcpy(&result, cursor_home);
810	(void) relative_move(&result, 0, 0, ynew, xnew, ovw);
811	break;
812    case 4:
813	(void) _nc_safe_strcpy(&result, cursor_to_ll);
814	(void) relative_move(&result, screen_lines - 1, 0, ynew, xnew, ovw);
815	break;
816    case 5:
817	if (xold > 0)
818	    (void) _nc_safe_strcat(&result, carriage_return);
819	(void) _nc_safe_strcat(&result, cursor_left);
820	(void) relative_move(&result, yold - 1, screen_columns - 1, ynew,
821			     xnew, ovw);
822	break;
823    }
824#endif /* !NO_OPTIMIZE */
825
826  nonlocal:
827#if defined(MAIN) || defined(NCURSES_TEST)
828    gettimeofday(&after, NULL);
829    diff = after.tv_usec - before.tv_usec
830	+ (after.tv_sec - before.tv_sec) * 1000000;
831    if (!profiling)
832	(void) fprintf(stderr,
833		       "onscreen: %d microsec, %f 28.8Kbps char-equivalents\n",
834		       (int) diff, diff / 288);
835#endif /* MAIN */
836
837    if (usecost != INFINITY) {
838	TPUTS_TRACE("mvcur");
839	tputs(buffer, 1, _nc_outch);
840	SP->_cursrow = ynew;
841	SP->_curscol = xnew;
842	return (OK);
843    } else
844	return (ERR);
845}
846
847NCURSES_EXPORT(int)
848mvcur(int yold, int xold, int ynew, int xnew)
849/* optimized cursor move from (yold, xold) to (ynew, xnew) */
850{
851    NCURSES_CH_T oldattr;
852    int code;
853
854    TR(TRACE_CALLS | TRACE_MOVE, (T_CALLED("mvcur(%d,%d,%d,%d)"),
855				  yold, xold, ynew, xnew));
856
857    if (SP == 0) {
858	code = ERR;
859    } else if (yold == ynew && xold == xnew) {
860	code = OK;
861    } else {
862
863	/*
864	 * Most work here is rounding for terminal boundaries getting the
865	 * column position implied by wraparound or the lack thereof and
866	 * rolling up the screen to get ynew on the screen.
867	 */
868	if (xnew >= screen_columns) {
869	    ynew += xnew / screen_columns;
870	    xnew %= screen_columns;
871	}
872
873	/*
874	 * Force restore even if msgr is on when we're in an alternate
875	 * character set -- these have a strong tendency to screw up the CR &
876	 * LF used for local character motions!
877	 */
878	oldattr = SCREEN_ATTRS(SP);
879	if ((AttrOf(oldattr) & A_ALTCHARSET)
880	    || (AttrOf(oldattr) && !move_standout_mode)) {
881	    TR(TRACE_CHARPUT, ("turning off (%#lx) %s before move",
882			       (unsigned long) AttrOf(oldattr),
883			       _traceattr(AttrOf(oldattr))));
884	    (void) VIDATTR(A_NORMAL, 0);
885	}
886
887	if (xold >= screen_columns) {
888	    int l;
889
890	    if (SP->_nl) {
891		l = (xold + 1) / screen_columns;
892		yold += l;
893		if (yold >= screen_lines)
894		    l -= (yold - screen_lines - 1);
895
896		if (l > 0) {
897		    if (carriage_return) {
898			TPUTS_TRACE("carriage_return");
899			putp(carriage_return);
900		    } else
901			_nc_outch('\r');
902		    xold = 0;
903
904		    while (l > 0) {
905			if (newline) {
906			    TPUTS_TRACE("newline");
907			    putp(newline);
908			} else
909			    _nc_outch('\n');
910			l--;
911		    }
912		}
913	    } else {
914		/*
915		 * If caller set nonl(), we cannot really use newlines to
916		 * position to the next row.
917		 */
918		xold = -1;
919		yold = -1;
920	    }
921	}
922
923	if (yold > screen_lines - 1)
924	    yold = screen_lines - 1;
925	if (ynew > screen_lines - 1)
926	    ynew = screen_lines - 1;
927
928	/* destination location is on screen now */
929	code = onscreen_mvcur(yold, xold, ynew, xnew, TRUE);
930
931	/*
932	 * Restore attributes if we disabled them before moving.
933	 */
934	if (!SameAttrOf(oldattr, SCREEN_ATTRS(SP))) {
935	    TR(TRACE_CHARPUT, ("turning on (%#lx) %s after move",
936			       (unsigned long) AttrOf(oldattr),
937			       _traceattr(AttrOf(oldattr))));
938	    (void) VIDATTR(AttrOf(oldattr), GetPair(oldattr));
939	}
940    }
941    returnCode(code);
942}
943
944#if defined(TRACE) || defined(NCURSES_TEST)
945NCURSES_EXPORT_VAR(int) _nc_optimize_enable = OPTIMIZE_ALL;
946#endif
947
948#if defined(MAIN) || defined(NCURSES_TEST)
949/****************************************************************************
950 *
951 * Movement optimizer test code
952 *
953 ****************************************************************************/
954
955#include <tic.h>
956#include <dump_entry.h>
957
958NCURSES_EXPORT_VAR(const char *) _nc_progname = "mvcur";
959
960static unsigned long xmits;
961
962/* these override lib_tputs.c */
963NCURSES_EXPORT(int)
964tputs(const char *string, int affcnt GCC_UNUSED, int (*outc) (int) GCC_UNUSED)
965/* stub tputs() that dumps sequences in a visible form */
966{
967    if (profiling)
968	xmits += strlen(string);
969    else
970	(void) fputs(_nc_visbuf(string), stdout);
971    return (OK);
972}
973
974NCURSES_EXPORT(int)
975putp(const char *string)
976{
977    return (tputs(string, 1, _nc_outch));
978}
979
980NCURSES_EXPORT(int)
981_nc_outch(int ch)
982{
983    putc(ch, stdout);
984    return OK;
985}
986
987NCURSES_EXPORT(int)
988delay_output(int ms GCC_UNUSED)
989{
990    return OK;
991}
992
993static char tname[PATH_MAX];
994
995static void
996load_term(void)
997{
998    (void) setupterm(tname, STDOUT_FILENO, NULL);
999}
1000
1001static int
1002roll(int n)
1003{
1004    int i, j;
1005
1006    i = (RAND_MAX / n) * n;
1007    while ((j = rand()) >= i)
1008	continue;
1009    return (j % n);
1010}
1011
1012int
1013main(int argc GCC_UNUSED, char *argv[]GCC_UNUSED)
1014{
1015    (void) strcpy(tname, termname());
1016    load_term();
1017    _nc_setupscreen(lines, columns, stdout);
1018    baudrate();
1019
1020    _nc_mvcur_init();
1021    NC_BUFFERED(FALSE);
1022
1023    (void) puts("The mvcur tester.  Type ? for help");
1024
1025    fputs("smcup:", stdout);
1026    putchar('\n');
1027
1028    for (;;) {
1029	int fy, fx, ty, tx, n, i;
1030	char buf[BUFSIZ], capname[BUFSIZ];
1031
1032	(void) fputs("> ", stdout);
1033	(void) fgets(buf, sizeof(buf), stdin);
1034
1035	if (buf[0] == '?') {
1036	    (void) puts("?                -- display this help message");
1037	    (void)
1038		puts("fy fx ty tx      -- (4 numbers) display (fy,fx)->(ty,tx) move");
1039	    (void) puts("s[croll] n t b m -- display scrolling sequence");
1040	    (void)
1041		printf("r[eload]         -- reload terminal info for %s\n",
1042		       termname());
1043	    (void)
1044		puts("l[oad] <term>    -- load terminal info for type <term>");
1045	    (void) puts("d[elete] <cap>   -- delete named capability");
1046	    (void) puts("i[nspect]        -- display terminal capabilities");
1047	    (void)
1048		puts("c[ost]           -- dump cursor-optimization cost table");
1049	    (void) puts("o[optimize]      -- toggle movement optimization");
1050	    (void)
1051		puts("t[orture] <num>  -- torture-test with <num> random moves");
1052	    (void) puts("q[uit]           -- quit the program");
1053	} else if (sscanf(buf, "%d %d %d %d", &fy, &fx, &ty, &tx) == 4) {
1054	    struct timeval before, after;
1055
1056	    putchar('"');
1057
1058	    gettimeofday(&before, NULL);
1059	    mvcur(fy, fx, ty, tx);
1060	    gettimeofday(&after, NULL);
1061
1062	    printf("\" (%ld msec)\n",
1063		   (long) (after.tv_usec - before.tv_usec
1064			   + (after.tv_sec - before.tv_sec)
1065			   * 1000000));
1066	} else if (sscanf(buf, "s %d %d %d %d", &fy, &fx, &ty, &tx) == 4) {
1067	    struct timeval before, after;
1068
1069	    putchar('"');
1070
1071	    gettimeofday(&before, NULL);
1072	    _nc_scrolln(fy, fx, ty, tx);
1073	    gettimeofday(&after, NULL);
1074
1075	    printf("\" (%ld msec)\n",
1076		   (long) (after.tv_usec - before.tv_usec + (after.tv_sec -
1077							     before.tv_sec)
1078			   * 1000000));
1079	} else if (buf[0] == 'r') {
1080	    (void) strcpy(tname, termname());
1081	    load_term();
1082	} else if (sscanf(buf, "l %s", tname) == 1) {
1083	    load_term();
1084	} else if (sscanf(buf, "d %s", capname) == 1) {
1085	    struct name_table_entry const *np = _nc_find_entry(capname,
1086							       _nc_info_hash_table);
1087
1088	    if (np == NULL)
1089		(void) printf("No such capability as \"%s\"\n", capname);
1090	    else {
1091		switch (np->nte_type) {
1092		case BOOLEAN:
1093		    cur_term->type.Booleans[np->nte_index] = FALSE;
1094		    (void)
1095			printf("Boolean capability `%s' (%d) turned off.\n",
1096			       np->nte_name, np->nte_index);
1097		    break;
1098
1099		case NUMBER:
1100		    cur_term->type.Numbers[np->nte_index] = ABSENT_NUMERIC;
1101		    (void) printf("Number capability `%s' (%d) set to -1.\n",
1102				  np->nte_name, np->nte_index);
1103		    break;
1104
1105		case STRING:
1106		    cur_term->type.Strings[np->nte_index] = ABSENT_STRING;
1107		    (void) printf("String capability `%s' (%d) deleted.\n",
1108				  np->nte_name, np->nte_index);
1109		    break;
1110		}
1111	    }
1112	} else if (buf[0] == 'i') {
1113	    dump_init((char *) NULL, F_TERMINFO, S_TERMINFO, 70, 0, FALSE);
1114	    dump_entry(&cur_term->type, FALSE, TRUE, 0, 0, 0);
1115	    putchar('\n');
1116	} else if (buf[0] == 'o') {
1117	    if (_nc_optimize_enable & OPTIMIZE_MVCUR) {
1118		_nc_optimize_enable &= ~OPTIMIZE_MVCUR;
1119		(void) puts("Optimization is now off.");
1120	    } else {
1121		_nc_optimize_enable |= OPTIMIZE_MVCUR;
1122		(void) puts("Optimization is now on.");
1123	    }
1124	}
1125	/*
1126	 * You can use the `t' test to profile and tune the movement
1127	 * optimizer.  Use iteration values in three digits or more.
1128	 * At above 5000 iterations the profile timing averages are stable
1129	 * to within a millisecond or three.
1130	 *
1131	 * The `overhead' field of the report will help you pick a
1132	 * COMPUTE_OVERHEAD figure appropriate for your processor and
1133	 * expected line speed.  The `total estimated time' is
1134	 * computation time plus a character-transmission time
1135	 * estimate computed from the number of transmits and the baud
1136	 * rate.
1137	 *
1138	 * Use this together with the `o' command to get a read on the
1139	 * optimizer's effectiveness.  Compare the total estimated times
1140	 * for `t' runs of the same length in both optimized and un-optimized
1141	 * modes.  As long as the optimized times are less, the optimizer
1142	 * is winning.
1143	 */
1144	else if (sscanf(buf, "t %d", &n) == 1) {
1145	    float cumtime = 0.0, perchar;
1146	    int speeds[] =
1147	    {2400, 9600, 14400, 19200, 28800, 38400, 0};
1148
1149	    srand((unsigned) (getpid() + time((time_t *) 0)));
1150	    profiling = TRUE;
1151	    xmits = 0;
1152	    for (i = 0; i < n; i++) {
1153		/*
1154		 * This does a move test between two random locations,
1155		 * Random moves probably short-change the optimizer,
1156		 * which will work better on the short moves probably
1157		 * typical of doupdate()'s usage pattern.  Still,
1158		 * until we have better data...
1159		 */
1160#ifdef FIND_COREDUMP
1161		int from_y = roll(lines);
1162		int to_y = roll(lines);
1163		int from_x = roll(columns);
1164		int to_x = roll(columns);
1165
1166		printf("(%d,%d) -> (%d,%d)\n", from_y, from_x, to_y, to_x);
1167		mvcur(from_y, from_x, to_y, to_x);
1168#else
1169		mvcur(roll(lines), roll(columns), roll(lines), roll(columns));
1170#endif /* FIND_COREDUMP */
1171		if (diff)
1172		    cumtime += diff;
1173	    }
1174	    profiling = FALSE;
1175
1176	    /*
1177	     * Average milliseconds per character optimization time.
1178	     * This is the key figure to watch when tuning the optimizer.
1179	     */
1180	    perchar = cumtime / n;
1181
1182	    (void) printf("%d moves (%ld chars) in %d msec, %f msec each:\n",
1183			  n, xmits, (int) cumtime, perchar);
1184
1185	    for (i = 0; speeds[i]; i++) {
1186		/*
1187		 * Total estimated time for the moves, computation and
1188		 * transmission both. Transmission time is an estimate
1189		 * assuming 9 bits/char, 8 bits + 1 stop bit.
1190		 */
1191		float totalest = cumtime + xmits * 9 * 1e6 / speeds[i];
1192
1193		/*
1194		 * Per-character optimization overhead in character transmits
1195		 * at the current speed.  Round this to the nearest integer
1196		 * to figure COMPUTE_OVERHEAD for the speed.
1197		 */
1198		float overhead = speeds[i] * perchar / 1e6;
1199
1200		(void)
1201		    printf("%6d bps: %3.2f char-xmits overhead; total estimated time %15.2f\n",
1202			   speeds[i], overhead, totalest);
1203	    }
1204	} else if (buf[0] == 'c') {
1205	    (void) printf("char padding: %d\n", SP->_char_padding);
1206	    (void) printf("cr cost: %d\n", SP->_cr_cost);
1207	    (void) printf("cup cost: %d\n", SP->_cup_cost);
1208	    (void) printf("home cost: %d\n", SP->_home_cost);
1209	    (void) printf("ll cost: %d\n", SP->_ll_cost);
1210#if USE_HARD_TABS
1211	    (void) printf("ht cost: %d\n", SP->_ht_cost);
1212	    (void) printf("cbt cost: %d\n", SP->_cbt_cost);
1213#endif /* USE_HARD_TABS */
1214	    (void) printf("cub1 cost: %d\n", SP->_cub1_cost);
1215	    (void) printf("cuf1 cost: %d\n", SP->_cuf1_cost);
1216	    (void) printf("cud1 cost: %d\n", SP->_cud1_cost);
1217	    (void) printf("cuu1 cost: %d\n", SP->_cuu1_cost);
1218	    (void) printf("cub cost: %d\n", SP->_cub_cost);
1219	    (void) printf("cuf cost: %d\n", SP->_cuf_cost);
1220	    (void) printf("cud cost: %d\n", SP->_cud_cost);
1221	    (void) printf("cuu cost: %d\n", SP->_cuu_cost);
1222	    (void) printf("hpa cost: %d\n", SP->_hpa_cost);
1223	    (void) printf("vpa cost: %d\n", SP->_vpa_cost);
1224	} else if (buf[0] == 'x' || buf[0] == 'q')
1225	    break;
1226	else
1227	    (void) puts("Invalid command.");
1228    }
1229
1230    (void) fputs("rmcup:", stdout);
1231    _nc_mvcur_wrap();
1232    putchar('\n');
1233
1234    return (0);
1235}
1236
1237#endif /* MAIN */
1238
1239/* lib_mvcur.c ends here */
1240