1/****************************************************************************
2 * Copyright (c) 1998-2007,2008 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 1.113 2008/08/16 19:30:58 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 (!GetNoPadding(SP))
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_2(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    if (getenv("NCURSES_NO_HARD_TABS") == 0) {
313	SP->_ht_cost = CostOf(tab, 0);
314	SP->_cbt_cost = CostOf(back_tab, 0);
315    } else {
316	SP->_ht_cost = INFINITY;
317	SP->_cbt_cost = INFINITY;
318    }
319#endif /* USE_HARD_TABS */
320    SP->_cub1_cost = CostOf(cursor_left, 0);
321    SP->_cuf1_cost = CostOf(cursor_right, 0);
322    SP->_cud1_cost = CostOf(cursor_down, 0);
323    SP->_cuu1_cost = CostOf(cursor_up, 0);
324
325    SP->_smir_cost = CostOf(enter_insert_mode, 0);
326    SP->_rmir_cost = CostOf(exit_insert_mode, 0);
327    SP->_ip_cost = 0;
328    if (insert_padding) {
329	SP->_ip_cost = CostOf(insert_padding, 0);
330    }
331
332    /*
333     * Assumption: if the terminal has memory_relative addressing, the
334     * initialization strings or smcup will set single-page mode so we
335     * can treat it like absolute screen addressing.  This seems to be true
336     * for all cursor_mem_address terminal types in the terminfo database.
337     */
338    SP->_address_cursor = cursor_address ? cursor_address : cursor_mem_address;
339
340    /*
341     * Parametrized local-motion strings.  This static cost computation
342     * depends on the following assumptions:
343     *
344     * (1) They never have * padding.  In the entire master terminfo database
345     *     as of March 1995, only the obsolete Zenith Z-100 pc violates this.
346     *     (Proportional padding is found mainly in insert, delete and scroll
347     *     capabilities).
348     *
349     * (2) The average case of cup has two two-digit parameters.  Strictly,
350     *     the average case for a 24 * 80 screen has ((10*10*(1 + 1)) +
351     *     (14*10*(1 + 2)) + (10*70*(2 + 1)) + (14*70*4)) / (24*80) = 3.458
352     *     digits of parameters.  On a 25x80 screen the average is 3.6197.
353     *     On larger screens the value gets much closer to 4.
354     *
355     * (3) The average case of cub/cuf/hpa/ech/rep has 2 digits of parameters
356     *     (strictly, (((10 * 1) + (70 * 2)) / 80) = 1.8750).
357     *
358     * (4) The average case of cud/cuu/vpa has 2 digits of parameters
359     *     (strictly, (((10 * 1) + (14 * 2)) / 24) = 1.5833).
360     *
361     * All these averages depend on the assumption that all parameter values
362     * are equally probable.
363     */
364    SP->_cup_cost = CostOf(TPARM_2(SP->_address_cursor, 23, 23), 1);
365    SP->_cub_cost = CostOf(TPARM_1(parm_left_cursor, 23), 1);
366    SP->_cuf_cost = CostOf(TPARM_1(parm_right_cursor, 23), 1);
367    SP->_cud_cost = CostOf(TPARM_1(parm_down_cursor, 23), 1);
368    SP->_cuu_cost = CostOf(TPARM_1(parm_up_cursor, 23), 1);
369    SP->_hpa_cost = CostOf(TPARM_1(column_address, 23), 1);
370    SP->_vpa_cost = CostOf(TPARM_1(row_address, 23), 1);
371
372    /* non-parameterized screen-update strings */
373    SP->_ed_cost = NormalizedCost(clr_eos, 1);
374    SP->_el_cost = NormalizedCost(clr_eol, 1);
375    SP->_el1_cost = NormalizedCost(clr_bol, 1);
376    SP->_dch1_cost = NormalizedCost(delete_character, 1);
377    SP->_ich1_cost = NormalizedCost(insert_character, 1);
378
379    /*
380     * If this is a bce-terminal, we want to bias the choice so we use clr_eol
381     * rather than spaces at the end of a line.
382     */
383    if (back_color_erase)
384	SP->_el_cost = 0;
385
386    /* parameterized screen-update strings */
387    SP->_dch_cost = NormalizedCost(TPARM_1(parm_dch, 23), 1);
388    SP->_ich_cost = NormalizedCost(TPARM_1(parm_ich, 23), 1);
389    SP->_ech_cost = NormalizedCost(TPARM_1(erase_chars, 23), 1);
390    SP->_rep_cost = NormalizedCost(TPARM_2(repeat_char, ' ', 23), 1);
391
392    SP->_cup_ch_cost = NormalizedCost(TPARM_2(SP->_address_cursor, 23, 23), 1);
393    SP->_hpa_ch_cost = NormalizedCost(TPARM_1(column_address, 23), 1);
394    SP->_cuf_ch_cost = NormalizedCost(TPARM_1(parm_right_cursor, 23), 1);
395    SP->_inline_cost = min(SP->_cup_ch_cost,
396			   min(SP->_hpa_ch_cost,
397			       SP->_cuf_ch_cost));
398
399    /*
400     * If save_cursor is used within enter_ca_mode, we should not use it for
401     * scrolling optimization, since the corresponding restore_cursor is not
402     * nested on the various terminals (vt100, xterm, etc.) which use this
403     * feature.
404     */
405    if (save_cursor != 0
406	&& enter_ca_mode != 0
407	&& strstr(enter_ca_mode, save_cursor) != 0) {
408	T(("...suppressed sc/rc capability due to conflict with smcup/rmcup"));
409	save_cursor = 0;
410	restore_cursor = 0;
411    }
412
413    /*
414     * A different, possibly better way to arrange this would be to set
415     * SP->_endwin = TRUE at window initialization time and let this be
416     * called by doupdate's return-from-shellout code.
417     */
418    _nc_mvcur_resume();
419}
420
421NCURSES_EXPORT(void)
422_nc_mvcur_wrap(void)
423/* wrap up cursor-addressing mode */
424{
425    /* leave cursor at screen bottom */
426    mvcur(-1, -1, screen_lines - 1, 0);
427
428    /* set cursor to normal mode */
429    if (SP->_cursor != -1) {
430	int cursor = SP->_cursor;
431	curs_set(1);
432	SP->_cursor = cursor;
433    }
434
435    if (exit_ca_mode) {
436	TPUTS_TRACE("exit_ca_mode");
437	putp(exit_ca_mode);
438    }
439    /*
440     * Reset terminal's tab counter.  There's a long-time bug that
441     * if you exit a "curses" program such as vi or more, tab
442     * forward, and then backspace, the cursor doesn't go to the
443     * right place.  The problem is that the kernel counts the
444     * escape sequences that reset things as column positions.
445     * Utter a \r to reset this invisibly.
446     */
447    _nc_outch('\r');
448}
449
450/****************************************************************************
451 *
452 * Optimized cursor movement
453 *
454 ****************************************************************************/
455
456/*
457 * Perform repeated-append, returning cost
458 */
459static NCURSES_INLINE int
460repeated_append(string_desc * target, int total, int num, int repeat, const char *src)
461{
462    size_t need = repeat * strlen(src);
463
464    if (need < target->s_size) {
465	while (repeat-- > 0) {
466	    if (_nc_safe_strcat(target, src)) {
467		total += num;
468	    } else {
469		total = INFINITY;
470		break;
471	    }
472	}
473    } else {
474	total = INFINITY;
475    }
476    return total;
477}
478
479#ifndef NO_OPTIMIZE
480#define NEXTTAB(fr)	(fr + init_tabs - (fr % init_tabs))
481
482/*
483 * Assume back_tab (CBT) does not wrap backwards at the left margin, return
484 * a negative value at that point to simplify the loop.
485 */
486#define LASTTAB(fr)	((fr > 0) ? ((fr - 1) / init_tabs) * init_tabs : -1)
487
488static int
489relative_move(string_desc * target, int from_y, int from_x, int to_y, int
490	      to_x, bool ovw)
491/* move via local motions (cuu/cuu1/cud/cud1/cub1/cub/cuf1/cuf/vpa/hpa) */
492{
493    string_desc save;
494    int n, vcost = 0, hcost = 0;
495
496    (void) _nc_str_copy(&save, target);
497
498    if (to_y != from_y) {
499	vcost = INFINITY;
500
501	if (row_address != 0
502	    && _nc_safe_strcat(target, TPARM_1(row_address, to_y))) {
503	    vcost = SP->_vpa_cost;
504	}
505
506	if (to_y > from_y) {
507	    n = (to_y - from_y);
508
509	    if (parm_down_cursor
510		&& SP->_cud_cost < vcost
511		&& _nc_safe_strcat(_nc_str_copy(target, &save),
512				   TPARM_1(parm_down_cursor, n))) {
513		vcost = SP->_cud_cost;
514	    }
515
516	    if (cursor_down
517		&& (*cursor_down != '\n' || SP->_nl)
518		&& (n * SP->_cud1_cost < vcost)) {
519		vcost = repeated_append(_nc_str_copy(target, &save), 0,
520					SP->_cud1_cost, n, cursor_down);
521	    }
522	} else {		/* (to_y < from_y) */
523	    n = (from_y - to_y);
524
525	    if (parm_up_cursor
526		&& SP->_cuu_cost < vcost
527		&& _nc_safe_strcat(_nc_str_copy(target, &save),
528				   TPARM_1(parm_up_cursor, n))) {
529		vcost = SP->_cuu_cost;
530	    }
531
532	    if (cursor_up && (n * SP->_cuu1_cost < vcost)) {
533		vcost = repeated_append(_nc_str_copy(target, &save), 0,
534					SP->_cuu1_cost, n, cursor_up);
535	    }
536	}
537
538	if (vcost == INFINITY)
539	    return (INFINITY);
540    }
541
542    save = *target;
543
544    if (to_x != from_x) {
545	char str[OPT_SIZE];
546	string_desc check;
547
548	hcost = INFINITY;
549
550	if (column_address
551	    && _nc_safe_strcat(_nc_str_copy(target, &save),
552			       TPARM_1(column_address, to_x))) {
553	    hcost = SP->_hpa_cost;
554	}
555
556	if (to_x > from_x) {
557	    n = to_x - from_x;
558
559	    if (parm_right_cursor
560		&& SP->_cuf_cost < hcost
561		&& _nc_safe_strcat(_nc_str_copy(target, &save),
562				   TPARM_1(parm_right_cursor, n))) {
563		hcost = SP->_cuf_cost;
564	    }
565
566	    if (cursor_right) {
567		int lhcost = 0;
568
569		(void) _nc_str_init(&check, str, sizeof(str));
570
571#if USE_HARD_TABS
572		/* use hard tabs, if we have them, to do as much as possible */
573		if (init_tabs > 0 && tab) {
574		    int nxt, fr;
575
576		    for (fr = from_x; (nxt = NEXTTAB(fr)) <= to_x; fr = nxt) {
577			lhcost = repeated_append(&check, lhcost,
578						 SP->_ht_cost, 1, tab);
579			if (lhcost == INFINITY)
580			    break;
581		    }
582
583		    n = to_x - fr;
584		    from_x = fr;
585		}
586#endif /* USE_HARD_TABS */
587
588		if (n <= 0 || n >= (int) check.s_size)
589		    ovw = FALSE;
590#if BSD_TPUTS
591		/*
592		 * If we're allowing BSD-style padding in tputs, don't generate
593		 * a string with a leading digit.  Otherwise, that will be
594		 * interpreted as a padding value rather than sent to the
595		 * screen.
596		 */
597		if (ovw
598		    && n > 0
599		    && n < (int) check.s_size
600		    && vcost == 0
601		    && str[0] == '\0') {
602		    int wanted = CharOf(WANT_CHAR(to_y, from_x));
603		    if (is8bits(wanted) && isdigit(wanted))
604			ovw = FALSE;
605		}
606#endif
607		/*
608		 * If we have no attribute changes, overwrite is cheaper.
609		 * Note: must suppress this by passing in ovw = FALSE whenever
610		 * WANT_CHAR would return invalid data.  In particular, this
611		 * is true between the time a hardware scroll has been done
612		 * and the time the structure WANT_CHAR would access has been
613		 * updated.
614		 */
615		if (ovw) {
616		    int i;
617
618		    for (i = 0; i < n; i++) {
619			NCURSES_CH_T ch = WANT_CHAR(to_y, from_x + i);
620			if (!SameAttrOf(ch, SCREEN_ATTRS(SP))
621#if USE_WIDEC_SUPPORT
622			    || !Charable(ch)
623#endif
624			    ) {
625			    ovw = FALSE;
626			    break;
627			}
628		    }
629		}
630		if (ovw) {
631		    int i;
632
633		    for (i = 0; i < n; i++)
634			*check.s_tail++ = (char) CharOf(WANT_CHAR(to_y,
635								  from_x + i));
636		    *check.s_tail = '\0';
637		    check.s_size -= n;
638		    lhcost += n * SP->_char_padding;
639		} else {
640		    lhcost = repeated_append(&check, lhcost, SP->_cuf1_cost,
641					     n, cursor_right);
642		}
643
644		if (lhcost < hcost
645		    && _nc_safe_strcat(_nc_str_copy(target, &save), str)) {
646		    hcost = lhcost;
647		}
648	    }
649	} else {		/* (to_x < from_x) */
650	    n = from_x - to_x;
651
652	    if (parm_left_cursor
653		&& SP->_cub_cost < hcost
654		&& _nc_safe_strcat(_nc_str_copy(target, &save),
655				   TPARM_1(parm_left_cursor, n))) {
656		hcost = SP->_cub_cost;
657	    }
658
659	    if (cursor_left) {
660		int lhcost = 0;
661
662		(void) _nc_str_init(&check, str, sizeof(str));
663
664#if USE_HARD_TABS
665		if (init_tabs > 0 && back_tab) {
666		    int nxt, fr;
667
668		    for (fr = from_x; (nxt = LASTTAB(fr)) >= to_x; fr = nxt) {
669			lhcost = repeated_append(&check, lhcost,
670						 SP->_cbt_cost, 1, back_tab);
671			if (lhcost == INFINITY)
672			    break;
673		    }
674
675		    n = fr - to_x;
676		}
677#endif /* USE_HARD_TABS */
678
679		lhcost = repeated_append(&check, lhcost, SP->_cub1_cost, n, cursor_left);
680
681		if (lhcost < hcost
682		    && _nc_safe_strcat(_nc_str_copy(target, &save), str)) {
683		    hcost = lhcost;
684		}
685	    }
686	}
687
688	if (hcost == INFINITY)
689	    return (INFINITY);
690    }
691
692    return (vcost + hcost);
693}
694#endif /* !NO_OPTIMIZE */
695
696/*
697 * With the machinery set up above, it's conceivable that
698 * onscreen_mvcur could be modified into a recursive function that does
699 * an alpha-beta search of motion space, as though it were a chess
700 * move tree, with the weight function being boolean and the search
701 * depth equated to length of string.  However, this would jack up the
702 * computation cost a lot, especially on terminals without a cup
703 * capability constraining the search tree depth.  So we settle for
704 * the simpler method below.
705 */
706
707static NCURSES_INLINE int
708onscreen_mvcur(int yold, int xold, int ynew, int xnew, bool ovw)
709/* onscreen move from (yold, xold) to (ynew, xnew) */
710{
711    string_desc result;
712    char buffer[OPT_SIZE];
713    int tactic = 0, newcost, usecost = INFINITY;
714    int t5_cr_cost;
715
716#if defined(MAIN) || defined(NCURSES_TEST)
717    struct timeval before, after;
718
719    gettimeofday(&before, NULL);
720#endif /* MAIN */
721
722#define NullResult _nc_str_null(&result, sizeof(buffer))
723#define InitResult _nc_str_init(&result, buffer, sizeof(buffer))
724
725    /* tactic #0: use direct cursor addressing */
726    if (_nc_safe_strcpy(InitResult, TPARM_2(SP->_address_cursor, ynew, xnew))) {
727	tactic = 0;
728	usecost = SP->_cup_cost;
729
730#if defined(TRACE) || defined(NCURSES_TEST)
731	if (!(_nc_optimize_enable & OPTIMIZE_MVCUR))
732	    goto nonlocal;
733#endif /* TRACE */
734
735	/*
736	 * We may be able to tell in advance that the full optimization
737	 * will probably not be worth its overhead.  Also, don't try to
738	 * use local movement if the current attribute is anything but
739	 * A_NORMAL...there are just too many ways this can screw up
740	 * (like, say, local-movement \n getting mapped to some obscure
741	 * character because A_ALTCHARSET is on).
742	 */
743	if (yold == -1 || xold == -1 || NOT_LOCAL(yold, xold, ynew, xnew)) {
744#if defined(MAIN) || defined(NCURSES_TEST)
745	    if (!profiling) {
746		(void) fputs("nonlocal\n", stderr);
747		goto nonlocal;	/* always run the optimizer if profiling */
748	    }
749#else
750	    goto nonlocal;
751#endif /* MAIN */
752	}
753    }
754#ifndef NO_OPTIMIZE
755    /* tactic #1: use local movement */
756    if (yold != -1 && xold != -1
757	&& ((newcost = relative_move(NullResult, yold, xold, ynew, xnew,
758				     ovw)) != INFINITY)
759	&& newcost < usecost) {
760	tactic = 1;
761	usecost = newcost;
762    }
763
764    /* tactic #2: use carriage-return + local movement */
765    if (yold != -1 && carriage_return
766	&& ((newcost = relative_move(NullResult, yold, 0, ynew, xnew, ovw))
767	    != INFINITY)
768	&& SP->_cr_cost + newcost < usecost) {
769	tactic = 2;
770	usecost = SP->_cr_cost + newcost;
771    }
772
773    /* tactic #3: use home-cursor + local movement */
774    if (cursor_home
775	&& ((newcost = relative_move(NullResult, 0, 0, ynew, xnew, ovw)) != INFINITY)
776	&& SP->_home_cost + newcost < usecost) {
777	tactic = 3;
778	usecost = SP->_home_cost + newcost;
779    }
780
781    /* tactic #4: use home-down + local movement */
782    if (cursor_to_ll
783	&& ((newcost = relative_move(NullResult, screen_lines - 1, 0, ynew,
784				     xnew, ovw)) != INFINITY)
785	&& SP->_ll_cost + newcost < usecost) {
786	tactic = 4;
787	usecost = SP->_ll_cost + newcost;
788    }
789
790    /*
791     * tactic #5: use left margin for wrap to right-hand side,
792     * unless strange wrap behavior indicated by xenl might hose us.
793     */
794    t5_cr_cost = (xold > 0 ? SP->_cr_cost : 0);
795    if (auto_left_margin && !eat_newline_glitch
796	&& yold > 0 && cursor_left
797	&& ((newcost = relative_move(NullResult, yold - 1, screen_columns -
798				     1, ynew, xnew, ovw)) != INFINITY)
799	&& t5_cr_cost + SP->_cub1_cost + newcost < usecost) {
800	tactic = 5;
801	usecost = t5_cr_cost + SP->_cub1_cost + newcost;
802    }
803
804    /*
805     * These cases are ordered by estimated relative frequency.
806     */
807    if (tactic)
808	InitResult;
809    switch (tactic) {
810    case 1:
811	(void) relative_move(&result, yold, xold, ynew, xnew, ovw);
812	break;
813    case 2:
814	(void) _nc_safe_strcpy(&result, carriage_return);
815	(void) relative_move(&result, yold, 0, ynew, xnew, ovw);
816	break;
817    case 3:
818	(void) _nc_safe_strcpy(&result, cursor_home);
819	(void) relative_move(&result, 0, 0, ynew, xnew, ovw);
820	break;
821    case 4:
822	(void) _nc_safe_strcpy(&result, cursor_to_ll);
823	(void) relative_move(&result, screen_lines - 1, 0, ynew, xnew, ovw);
824	break;
825    case 5:
826	if (xold > 0)
827	    (void) _nc_safe_strcat(&result, carriage_return);
828	(void) _nc_safe_strcat(&result, cursor_left);
829	(void) relative_move(&result, yold - 1, screen_columns - 1, ynew,
830			     xnew, ovw);
831	break;
832    }
833#endif /* !NO_OPTIMIZE */
834
835  nonlocal:
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,
842		       "onscreen: %d microsec, %f 28.8Kbps char-equivalents\n",
843		       (int) diff, diff / 288);
844#endif /* MAIN */
845
846    if (usecost != INFINITY) {
847	TPUTS_TRACE("mvcur");
848	tputs(buffer, 1, _nc_outch);
849	SP->_cursrow = ynew;
850	SP->_curscol = xnew;
851	return (OK);
852    } else
853	return (ERR);
854}
855
856NCURSES_EXPORT(int)
857mvcur(int yold, int xold, int ynew, int xnew)
858/* optimized cursor move from (yold, xold) to (ynew, xnew) */
859{
860    NCURSES_CH_T oldattr;
861    int code;
862
863    TR(TRACE_CALLS | TRACE_MOVE, (T_CALLED("mvcur(%d,%d,%d,%d)"),
864				  yold, xold, ynew, xnew));
865
866    if (SP == 0) {
867	code = ERR;
868    } else if (yold == ynew && xold == xnew) {
869	code = OK;
870    } else {
871
872	/*
873	 * Most work here is rounding for terminal boundaries getting the
874	 * column position implied by wraparound or the lack thereof and
875	 * rolling up the screen to get ynew on the screen.
876	 */
877	if (xnew >= screen_columns) {
878	    ynew += xnew / screen_columns;
879	    xnew %= screen_columns;
880	}
881
882	/*
883	 * Force restore even if msgr is on when we're in an alternate
884	 * character set -- these have a strong tendency to screw up the CR &
885	 * LF used for local character motions!
886	 */
887	oldattr = SCREEN_ATTRS(SP);
888	if ((AttrOf(oldattr) & A_ALTCHARSET)
889	    || (AttrOf(oldattr) && !move_standout_mode)) {
890	    TR(TRACE_CHARPUT, ("turning off (%#lx) %s before move",
891			       (unsigned long) AttrOf(oldattr),
892			       _traceattr(AttrOf(oldattr))));
893	    (void) VIDATTR(A_NORMAL, 0);
894	}
895
896	if (xold >= screen_columns) {
897	    int l;
898
899	    if (SP->_nl) {
900		l = (xold + 1) / screen_columns;
901		yold += l;
902		if (yold >= screen_lines)
903		    l -= (yold - screen_lines - 1);
904
905		if (l > 0) {
906		    if (carriage_return) {
907			TPUTS_TRACE("carriage_return");
908			putp(carriage_return);
909		    } else
910			_nc_outch('\r');
911		    xold = 0;
912
913		    while (l > 0) {
914			if (newline) {
915			    TPUTS_TRACE("newline");
916			    putp(newline);
917			} else
918			    _nc_outch('\n');
919			l--;
920		    }
921		}
922	    } else {
923		/*
924		 * If caller set nonl(), we cannot really use newlines to
925		 * position to the next row.
926		 */
927		xold = -1;
928		yold = -1;
929	    }
930	}
931
932	if (yold > screen_lines - 1)
933	    yold = screen_lines - 1;
934	if (ynew > screen_lines - 1)
935	    ynew = screen_lines - 1;
936
937	/* destination location is on screen now */
938	code = onscreen_mvcur(yold, xold, ynew, xnew, TRUE);
939
940	/*
941	 * Restore attributes if we disabled them before moving.
942	 */
943	if (!SameAttrOf(oldattr, SCREEN_ATTRS(SP))) {
944	    TR(TRACE_CHARPUT, ("turning on (%#lx) %s after move",
945			       (unsigned long) AttrOf(oldattr),
946			       _traceattr(AttrOf(oldattr))));
947	    (void) VIDATTR(AttrOf(oldattr), GetPair(oldattr));
948	}
949    }
950    returnCode(code);
951}
952
953#if defined(TRACE) || defined(NCURSES_TEST)
954NCURSES_EXPORT_VAR(int) _nc_optimize_enable = OPTIMIZE_ALL;
955#endif
956
957#if defined(MAIN) || defined(NCURSES_TEST)
958/****************************************************************************
959 *
960 * Movement optimizer test code
961 *
962 ****************************************************************************/
963
964#include <tic.h>
965#include <dump_entry.h>
966#include <time.h>
967
968NCURSES_EXPORT_VAR(const char *) _nc_progname = "mvcur";
969
970static unsigned long xmits;
971
972/* these override lib_tputs.c */
973NCURSES_EXPORT(int)
974tputs(const char *string, int affcnt GCC_UNUSED, int (*outc) (int) GCC_UNUSED)
975/* stub tputs() that dumps sequences in a visible form */
976{
977    if (profiling)
978	xmits += strlen(string);
979    else
980	(void) fputs(_nc_visbuf(string), stdout);
981    return (OK);
982}
983
984NCURSES_EXPORT(int)
985putp(const char *string)
986{
987    return (tputs(string, 1, _nc_outch));
988}
989
990NCURSES_EXPORT(int)
991_nc_outch(int ch)
992{
993    putc(ch, stdout);
994    return OK;
995}
996
997NCURSES_EXPORT(int)
998delay_output(int ms GCC_UNUSED)
999{
1000    return OK;
1001}
1002
1003static char tname[PATH_MAX];
1004
1005static void
1006load_term(void)
1007{
1008    (void) setupterm(tname, STDOUT_FILENO, NULL);
1009}
1010
1011static int
1012roll(int n)
1013{
1014    int i, j;
1015
1016    i = (RAND_MAX / n) * n;
1017    while ((j = rand()) >= i)
1018	continue;
1019    return (j % n);
1020}
1021
1022int
1023main(int argc GCC_UNUSED, char *argv[]GCC_UNUSED)
1024{
1025    strcpy(tname, getenv("TERM"));
1026    load_term();
1027    _nc_setupscreen(lines, columns, stdout, FALSE, 0);
1028    baudrate();
1029
1030    _nc_mvcur_init();
1031    NC_BUFFERED(FALSE);
1032
1033    (void) puts("The mvcur tester.  Type ? for help");
1034
1035    fputs("smcup:", stdout);
1036    putchar('\n');
1037
1038    for (;;) {
1039	int fy, fx, ty, tx, n, i;
1040	char buf[BUFSIZ], capname[BUFSIZ];
1041
1042	(void) fputs("> ", stdout);
1043	(void) fgets(buf, sizeof(buf), stdin);
1044
1045	if (buf[0] == '?') {
1046	    (void) puts("?                -- display this help message");
1047	    (void)
1048		puts("fy fx ty tx      -- (4 numbers) display (fy,fx)->(ty,tx) move");
1049	    (void) puts("s[croll] n t b m -- display scrolling sequence");
1050	    (void)
1051		printf("r[eload]         -- reload terminal info for %s\n",
1052		       termname());
1053	    (void)
1054		puts("l[oad] <term>    -- load terminal info for type <term>");
1055	    (void) puts("d[elete] <cap>   -- delete named capability");
1056	    (void) puts("i[nspect]        -- display terminal capabilities");
1057	    (void)
1058		puts("c[ost]           -- dump cursor-optimization cost table");
1059	    (void) puts("o[optimize]      -- toggle movement optimization");
1060	    (void)
1061		puts("t[orture] <num>  -- torture-test with <num> random moves");
1062	    (void) puts("q[uit]           -- quit the program");
1063	} else if (sscanf(buf, "%d %d %d %d", &fy, &fx, &ty, &tx) == 4) {
1064	    struct timeval before, after;
1065
1066	    putchar('"');
1067
1068	    gettimeofday(&before, NULL);
1069	    mvcur(fy, fx, ty, tx);
1070	    gettimeofday(&after, NULL);
1071
1072	    printf("\" (%ld msec)\n",
1073		   (long) (after.tv_usec - before.tv_usec
1074			   + (after.tv_sec - before.tv_sec)
1075			   * 1000000));
1076	} else if (sscanf(buf, "s %d %d %d %d", &fy, &fx, &ty, &tx) == 4) {
1077	    struct timeval before, after;
1078
1079	    putchar('"');
1080
1081	    gettimeofday(&before, NULL);
1082	    _nc_scrolln(fy, fx, ty, tx);
1083	    gettimeofday(&after, NULL);
1084
1085	    printf("\" (%ld msec)\n",
1086		   (long) (after.tv_usec - before.tv_usec + (after.tv_sec -
1087							     before.tv_sec)
1088			   * 1000000));
1089	} else if (buf[0] == 'r') {
1090	    (void) strcpy(tname, termname());
1091	    load_term();
1092	} else if (sscanf(buf, "l %s", tname) == 1) {
1093	    load_term();
1094	} else if (sscanf(buf, "d %s", capname) == 1) {
1095	    struct name_table_entry const *np = _nc_find_entry(capname,
1096							       _nc_get_hash_table(FALSE));
1097
1098	    if (np == NULL)
1099		(void) printf("No such capability as \"%s\"\n", capname);
1100	    else {
1101		switch (np->nte_type) {
1102		case BOOLEAN:
1103		    cur_term->type.Booleans[np->nte_index] = FALSE;
1104		    (void)
1105			printf("Boolean capability `%s' (%d) turned off.\n",
1106			       np->nte_name, np->nte_index);
1107		    break;
1108
1109		case NUMBER:
1110		    cur_term->type.Numbers[np->nte_index] = ABSENT_NUMERIC;
1111		    (void) printf("Number capability `%s' (%d) set to -1.\n",
1112				  np->nte_name, np->nte_index);
1113		    break;
1114
1115		case STRING:
1116		    cur_term->type.Strings[np->nte_index] = ABSENT_STRING;
1117		    (void) printf("String capability `%s' (%d) deleted.\n",
1118				  np->nte_name, np->nte_index);
1119		    break;
1120		}
1121	    }
1122	} else if (buf[0] == 'i') {
1123	    dump_init((char *) NULL, F_TERMINFO, S_TERMINFO, 70, 0, FALSE);
1124	    dump_entry(&cur_term->type, FALSE, TRUE, 0, 0);
1125	    putchar('\n');
1126	} else if (buf[0] == 'o') {
1127	    if (_nc_optimize_enable & OPTIMIZE_MVCUR) {
1128		_nc_optimize_enable &= ~OPTIMIZE_MVCUR;
1129		(void) puts("Optimization is now off.");
1130	    } else {
1131		_nc_optimize_enable |= OPTIMIZE_MVCUR;
1132		(void) puts("Optimization is now on.");
1133	    }
1134	}
1135	/*
1136	 * You can use the `t' test to profile and tune the movement
1137	 * optimizer.  Use iteration values in three digits or more.
1138	 * At above 5000 iterations the profile timing averages are stable
1139	 * to within a millisecond or three.
1140	 *
1141	 * The `overhead' field of the report will help you pick a
1142	 * COMPUTE_OVERHEAD figure appropriate for your processor and
1143	 * expected line speed.  The `total estimated time' is
1144	 * computation time plus a character-transmission time
1145	 * estimate computed from the number of transmits and the baud
1146	 * rate.
1147	 *
1148	 * Use this together with the `o' command to get a read on the
1149	 * optimizer's effectiveness.  Compare the total estimated times
1150	 * for `t' runs of the same length in both optimized and un-optimized
1151	 * modes.  As long as the optimized times are less, the optimizer
1152	 * is winning.
1153	 */
1154	else if (sscanf(buf, "t %d", &n) == 1) {
1155	    float cumtime = 0.0, perchar;
1156	    int speeds[] =
1157	    {2400, 9600, 14400, 19200, 28800, 38400, 0};
1158
1159	    srand((unsigned) (getpid() + time((time_t *) 0)));
1160	    profiling = TRUE;
1161	    xmits = 0;
1162	    for (i = 0; i < n; i++) {
1163		/*
1164		 * This does a move test between two random locations,
1165		 * Random moves probably short-change the optimizer,
1166		 * which will work better on the short moves probably
1167		 * typical of doupdate()'s usage pattern.  Still,
1168		 * until we have better data...
1169		 */
1170#ifdef FIND_COREDUMP
1171		int from_y = roll(lines);
1172		int to_y = roll(lines);
1173		int from_x = roll(columns);
1174		int to_x = roll(columns);
1175
1176		printf("(%d,%d) -> (%d,%d)\n", from_y, from_x, to_y, to_x);
1177		mvcur(from_y, from_x, to_y, to_x);
1178#else
1179		mvcur(roll(lines), roll(columns), roll(lines), roll(columns));
1180#endif /* FIND_COREDUMP */
1181		if (diff)
1182		    cumtime += diff;
1183	    }
1184	    profiling = FALSE;
1185
1186	    /*
1187	     * Average milliseconds per character optimization time.
1188	     * This is the key figure to watch when tuning the optimizer.
1189	     */
1190	    perchar = cumtime / n;
1191
1192	    (void) printf("%d moves (%ld chars) in %d msec, %f msec each:\n",
1193			  n, xmits, (int) cumtime, perchar);
1194
1195	    for (i = 0; speeds[i]; i++) {
1196		/*
1197		 * Total estimated time for the moves, computation and
1198		 * transmission both. Transmission time is an estimate
1199		 * assuming 9 bits/char, 8 bits + 1 stop bit.
1200		 */
1201		float totalest = cumtime + xmits * 9 * 1e6 / speeds[i];
1202
1203		/*
1204		 * Per-character optimization overhead in character transmits
1205		 * at the current speed.  Round this to the nearest integer
1206		 * to figure COMPUTE_OVERHEAD for the speed.
1207		 */
1208		float overhead = speeds[i] * perchar / 1e6;
1209
1210		(void)
1211		    printf("%6d bps: %3.2f char-xmits overhead; total estimated time %15.2f\n",
1212			   speeds[i], overhead, totalest);
1213	    }
1214	} else if (buf[0] == 'c') {
1215	    (void) printf("char padding: %d\n", SP->_char_padding);
1216	    (void) printf("cr cost: %d\n", SP->_cr_cost);
1217	    (void) printf("cup cost: %d\n", SP->_cup_cost);
1218	    (void) printf("home cost: %d\n", SP->_home_cost);
1219	    (void) printf("ll cost: %d\n", SP->_ll_cost);
1220#if USE_HARD_TABS
1221	    (void) printf("ht cost: %d\n", SP->_ht_cost);
1222	    (void) printf("cbt cost: %d\n", SP->_cbt_cost);
1223#endif /* USE_HARD_TABS */
1224	    (void) printf("cub1 cost: %d\n", SP->_cub1_cost);
1225	    (void) printf("cuf1 cost: %d\n", SP->_cuf1_cost);
1226	    (void) printf("cud1 cost: %d\n", SP->_cud1_cost);
1227	    (void) printf("cuu1 cost: %d\n", SP->_cuu1_cost);
1228	    (void) printf("cub cost: %d\n", SP->_cub_cost);
1229	    (void) printf("cuf cost: %d\n", SP->_cuf_cost);
1230	    (void) printf("cud cost: %d\n", SP->_cud_cost);
1231	    (void) printf("cuu cost: %d\n", SP->_cuu_cost);
1232	    (void) printf("hpa cost: %d\n", SP->_hpa_cost);
1233	    (void) printf("vpa cost: %d\n", SP->_vpa_cost);
1234	} else if (buf[0] == 'x' || buf[0] == 'q')
1235	    break;
1236	else
1237	    (void) puts("Invalid command.");
1238    }
1239
1240    (void) fputs("rmcup:", stdout);
1241    _nc_mvcur_wrap();
1242    putchar('\n');
1243
1244    return (0);
1245}
1246
1247#endif /* MAIN */
1248
1249/* lib_mvcur.c ends here */
1250