/* $OpenBSD: lib_mvcur.c,v 1.13 2010/01/12 23:22:07 nicm Exp $ */

/****************************************************************************

 * Copyright (c) 1998-2007,2008 Free Software Foundation, Inc.              *

 *                                                                          *

 * Permission is hereby granted, free of charge, to any person obtaining a  *

 * copy of this software and associated documentation files (the            *

 * "Software"), to deal in the Software without restriction, including      *

 * without limitation the rights to use, copy, modify, merge, publish,      *

 * distribute, distribute with modifications, sublicense, and/or sell       *

 * copies of the Software, and to permit persons to whom the Software is    *

 * furnished to do so, subject to the following conditions:                 *

 *                                                                          *

 * The above copyright notice and this permission notice shall be included  *

 * in all copies or substantial portions of the Software.                   *

 *                                                                          *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *

 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *

 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *

 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *

 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *

 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *

 *                                                                          *

 * Except as contained in this notice, the name(s) of the above copyright   *

 * holders shall not be used in advertising or otherwise to promote the     *

 * sale, use or other dealings in this Software without prior written       *

 * authorization.                                                           *

 ****************************************************************************/

/****************************************************************************

 *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *

 *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *

 *     and: Thomas E. Dickey                        1996-on                 *

 ****************************************************************************/

/*

**	lib_mvcur.c

**

**	The routines for moving the physical cursor and scrolling:

**

**		void _nc_mvcur_init(void)

**

**		void _nc_mvcur_resume(void)

**

**		int mvcur(int old_y, int old_x, int new_y, int new_x)

**

**		void _nc_mvcur_wrap(void)

**

** Comparisons with older movement optimizers:

**    SVr3 curses mvcur() can't use cursor_to_ll or auto_left_margin.

**    4.4BSD curses can't use cuu/cud/cuf/cub/hpa/vpa/tab/cbt for local

** motions.  It doesn't use tactics based on auto_left_margin.  Weirdly

** enough, it doesn't use its own hardware-scrolling routine to scroll up

** destination lines for out-of-bounds addresses!

**    old ncurses optimizer: less accurate cost computations (in fact,

** it was broken and had to be commented out!).

**

** Compile with -DMAIN to build an interactive tester/timer for the movement

** optimizer.  You can use it to investigate the optimizer's behavior.

** You can also use it for tuning the formulas used to determine whether

** or not full optimization is attempted.

**

** This code has a nasty tendency to find bugs in terminfo entries, because it

** exercises the non-cup movement capabilities heavily.  If you think you've

** found a bug, try deleting subsets of the following capabilities (arranged

** in decreasing order of suspiciousness): it, tab, cbt, hpa, vpa, cuu, cud,

** cuf, cub, cuu1, cud1, cuf1, cub1.  It may be that one or more are wrong.

**

** Note: you should expect this code to look like a resource hog in a profile.

** That's because it does a lot of I/O, through the tputs() calls.  The I/O

** cost swamps the computation overhead (and as machines get faster, this

** will become even more true).  Comments in the test exerciser at the end

** go into detail about tuning and how you can gauge the optimizer's

** effectiveness.

**/

/****************************************************************************

 *

 * Constants and macros for optimizer tuning.

 *

 ****************************************************************************/

/*

 * The average overhead of a full optimization computation in character

 * transmission times.  If it's too high, the algorithm will be a bit

 * over-biased toward using cup rather than local motions; if it's too

 * low, the algorithm may spend more time than is strictly optimal

 * looking for non-cup motions.  Profile the optimizer using the `t'

 * command of the exerciser (see below), and round to the nearest integer.

 *

 * Yes, I (esr) thought about computing expected overhead dynamically, say

 * by derivation from a running average of optimizer times.  But the

 * whole point of this optimization is to *decrease* the frequency of

 * system calls. :-)

 */

#define COMPUTE_OVERHEAD	1	/* I use a 90MHz Pentium @ 9.6Kbps */

/*

 * LONG_DIST is the distance we consider to be just as costly to move over as a

 * cup sequence is to emit.  In other words, it's the length of a cup sequence

 * adjusted for average computation overhead.  The magic number is the length

 * of "\033[yy;xxH", the typical cup sequence these days.

 */

#define LONG_DIST		(8 - COMPUTE_OVERHEAD)

/*

 * Tell whether a motion is optimizable by local motions.  Needs to be cheap to

 * compute. In general, all the fast moves go to either the right or left edge

 * of the screen.  So any motion to a location that is (a) further away than

 * LONG_DIST and (b) further inward from the right or left edge than LONG_DIST,

 * we'll consider nonlocal.

 */

#define NOT_LOCAL(fy, fx, ty, tx)	((tx > LONG_DIST) \

 		 && (tx < screen_columns - 1 - LONG_DIST) \

		 && (abs(ty-fy) + abs(tx-fx) > LONG_DIST))

/****************************************************************************

 *

 * External interfaces

 *

 ****************************************************************************/

/*

 * For this code to work OK, the following components must live in the

 * screen structure:

 *

 *	int		_char_padding;	// cost of character put

 *	int		_cr_cost;	// cost of (carriage_return)

 *	int		_cup_cost;	// cost of (cursor_address)

 *	int		_home_cost;	// cost of (cursor_home)

 *	int		_ll_cost;	// cost of (cursor_to_ll)

 *#if USE_HARD_TABS

 *	int		_ht_cost;	// cost of (tab)

 *	int		_cbt_cost;	// cost of (back_tab)

 *#endif USE_HARD_TABS

 *	int		_cub1_cost;	// cost of (cursor_left)

 *	int		_cuf1_cost;	// cost of (cursor_right)

 *	int		_cud1_cost;	// cost of (cursor_down)

 *	int		_cuu1_cost;	// cost of (cursor_up)

 *	int		_cub_cost;	// cost of (parm_cursor_left)

 *	int		_cuf_cost;	// cost of (parm_cursor_right)

 *	int		_cud_cost;	// cost of (parm_cursor_down)

 *	int		_cuu_cost;	// cost of (parm_cursor_up)

 *	int		_hpa_cost;	// cost of (column_address)

 *	int		_vpa_cost;	// cost of (row_address)

 *	int		_ech_cost;	// cost of (erase_chars)

 *	int		_rep_cost;	// cost of (repeat_char)

 *

 * The USE_HARD_TABS switch controls whether it is reliable to use tab/backtabs

 * for local motions.  On many systems, it's not, due to uncertainties about

 * tab delays and whether or not tabs will be expanded in raw mode.  If you

 * have parm_right_cursor, tab motions don't win you a lot anyhow.

 */

#include <curses.priv.h>

#include <term.h>

#include <ctype.h>

MODULE_ID("$Id: lib_mvcur.c,v 1.13 2010/01/12 23:22:07 nicm Exp $")

#define WANT_CHAR(y, x)	SP->_newscr->_line[y].text[x]	/* desired state */

#define BAUDRATE	cur_term->_baudrate	/* bits per second */

#if defined(MAIN) || defined(NCURSES_TEST)

#include <sys/time.h>

static bool profiling = FALSE;

static float diff;

#endif /* MAIN */

#define OPT_SIZE 512

static int normalized_cost(const char *const cap, int affcnt);

/****************************************************************************

 *

 * Initialization/wrapup (including cost pre-computation)

 *

 ****************************************************************************/

#ifdef TRACE

static int

trace_cost_of(const char *capname, const char *cap, int affcnt)

{

    int result = _nc_msec_cost(cap, affcnt);

    TR(TRACE_CHARPUT | TRACE_MOVE,

       ("CostOf %s %d %s", capname, result, _nc_visbuf(cap)));

    return result;

}

#define CostOf(cap,affcnt) trace_cost_of(#cap,cap,affcnt);

static int

trace_normalized_cost(const char *capname, const char *cap, int affcnt)

{

    int result = normalized_cost(cap, affcnt);

    TR(TRACE_CHARPUT | TRACE_MOVE,

       ("NormalizedCost %s %d %s", capname, result, _nc_visbuf(cap)));

    return result;

}

#define NormalizedCost(cap,affcnt) trace_normalized_cost(#cap,cap,affcnt);

#else

#define CostOf(cap,affcnt) _nc_msec_cost(cap,affcnt);

#define NormalizedCost(cap,affcnt) normalized_cost(cap,affcnt);

#endif

NCURSES_EXPORT(int)

_nc_msec_cost(const char *const cap, int affcnt)

/* compute the cost of a given operation */

{

    else {

	const char *cp;

	float cum_cost = 0.0;

	    /* extract padding, either mandatory or required */

		float number = 0.0;

		}

#if NCURSES_NO_PADDING

#endif

	}

    }

}

static int

normalized_cost(const char *const cap, int affcnt)

/* compute the effective character-count for an operation (round up) */

{

}

static void

reset_scroll_region(void)

/* Set the scroll-region to a known state (the default) */

{

	TPUTS_TRACE("change_scroll_region");

    }

}

NCURSES_EXPORT(void)

_nc_mvcur_resume(void)

/* what to do at initialization time and after each shellout */

{

    /* initialize screen for cursor access */

	TPUTS_TRACE("enter_ca_mode");

    }

    /*

     * Doing this here rather than in _nc_mvcur_wrap() ensures that

     * ncurses programs will see a reset scroll region even if a

     * program that messed with it died ungracefully.

     *

     * This also undoes the effects of terminal init strings that assume

     * they know the screen size.  This is useful when you're running

     * a vt100 emulation through xterm.

     */

    /* restore cursor shape */

	int cursor = SP->_cursor;

    }

}

NCURSES_EXPORT(void)

_nc_mvcur_init(void)

/* initialize the cost structure */

{

    else

	SP->_char_padding = 1;	/* must be nonzero */

    TR(TRACE_CHARPUT | TRACE_MOVE, ("char_padding %d msecs", SP->_char_padding));

    /* non-parameterized local-motion strings */

#if USE_HARD_TABS

    if (getenv("NCURSES_NO_HARD_TABS") == 0) {

	SP->_ht_cost = CostOf(tab, 0);

	SP->_cbt_cost = CostOf(back_tab, 0);

    } else {

	SP->_ht_cost = INFINITY;

	SP->_cbt_cost = INFINITY;

    }

#endif /* USE_HARD_TABS */

    }

    /*

     * Assumption: if the terminal has memory_relative addressing, the

     * initialization strings or smcup will set single-page mode so we

     * can treat it like absolute screen addressing.  This seems to be true

     * for all cursor_mem_address terminal types in the terminfo database.

     */

    /*

     * Parametrized local-motion strings.  This static cost computation

     * depends on the following assumptions:

     *

     * (1) They never have * padding.  In the entire master terminfo database

     *     as of March 1995, only the obsolete Zenith Z-100 pc violates this.

     *     (Proportional padding is found mainly in insert, delete and scroll

     *     capabilities).

     *

     * (2) The average case of cup has two two-digit parameters.  Strictly,

     *     the average case for a 24 * 80 screen has ((10*10*(1 + 1)) +

     *     (14*10*(1 + 2)) + (10*70*(2 + 1)) + (14*70*4)) / (24*80) = 3.458

     *     digits of parameters.  On a 25x80 screen the average is 3.6197.

     *     On larger screens the value gets much closer to 4.

     *

     * (3) The average case of cub/cuf/hpa/ech/rep has 2 digits of parameters

     *     (strictly, (((10 * 1) + (70 * 2)) / 80) = 1.8750).

     *

     * (4) The average case of cud/cuu/vpa has 2 digits of parameters

     *     (strictly, (((10 * 1) + (14 * 2)) / 24) = 1.5833).

     *

     * All these averages depend on the assumption that all parameter values

     * are equally probable.

     */

    /* non-parameterized screen-update strings */

    /*

     * If this is a bce-terminal, we want to bias the choice so we use clr_eol

     * rather than spaces at the end of a line.

     */

    /* parameterized screen-update strings */

			   min(SP->_hpa_ch_cost,

			       SP->_cuf_ch_cost));

    /*

     * If save_cursor is used within enter_ca_mode, we should not use it for

     * scrolling optimization, since the corresponding restore_cursor is not

     * nested on the various terminals (vt100, xterm, etc.) which use this

     * feature.

     */

	T(("...suppressed sc/rc capability due to conflict with smcup/rmcup"));

    }

    /*

     * A different, possibly better way to arrange this would be to set

     * SP->_endwin = TRUE at window initialization time and let this be

     * called by doupdate's return-from-shellout code.

     */

}

NCURSES_EXPORT(void)

_nc_mvcur_wrap(void)

/* wrap up cursor-addressing mode */

{

    /* leave cursor at screen bottom */

    /* set cursor to normal mode */

	int cursor = SP->_cursor;

    }

	TPUTS_TRACE("exit_ca_mode");

    }

    /*

     * Reset terminal's tab counter.  There's a long-time bug that

     * if you exit a "curses" program such as vi or more, tab

     * forward, and then backspace, the cursor doesn't go to the

     * right place.  The problem is that the kernel counts the

     * escape sequences that reset things as column positions.

     * Utter a \r to reset this invisibly.

     */

}

/****************************************************************************

 *

 * Optimized cursor movement

 *

 ****************************************************************************/

/*

 * Perform repeated-append, returning cost

 */

static NCURSES_INLINE int

repeated_append(string_desc * target, int total, int num, int repeat, const char *src)

{

	    } else {

		total = INFINITY;

	    }

	}

    } else {

	total = INFINITY;

    }

}

#ifndef NO_OPTIMIZE

#define NEXTTAB(fr)	(fr + init_tabs - (fr % init_tabs))

/*

 * Assume back_tab (CBT) does not wrap backwards at the left margin, return

 * a negative value at that point to simplify the loop.

 */

#define LASTTAB(fr)	((fr > 0) ? ((fr - 1) / init_tabs) * init_tabs : -1)

static int

relative_move(string_desc * target, int from_y, int from_x, int to_y, int

	      to_x, bool ovw)

/* move via local motions (cuu/cuu1/cud/cud1/cub1/cub/cuf1/cuf/vpa/hpa) */

{

    int n, vcost = 0, hcost = 0;

	vcost = INFINITY;

	}

	    }

	    }

	} else {		/* (to_y < from_y) */

	    }

	    }

	}

    }

	hcost = INFINITY;

	}

	    }

		int lhcost = 0;

#if USE_HARD_TABS

		/* use hard tabs, if we have them, to do as much as possible */

		if (init_tabs > 0 && tab) {

		    int nxt, fr;

		    for (fr = from_x; (nxt = NEXTTAB(fr)) <= to_x; fr = nxt) {

			lhcost = repeated_append(&check, lhcost,

						 SP->_ht_cost, 1, tab);

			if (lhcost == INFINITY)

			    break;

		    }

		    n = to_x - fr;

		    from_x = fr;

		}

#endif /* USE_HARD_TABS */

#if BSD_TPUTS

		/*

		 * If we're allowing BSD-style padding in tputs, don't generate

		 * a string with a leading digit.  Otherwise, that will be

		 * interpreted as a padding value rather than sent to the

		 * screen.

		 */

		}

#endif

		/*

		 * If we have no attribute changes, overwrite is cheaper.

		 * Note: must suppress this by passing in ovw = FALSE whenever

		 * WANT_CHAR would return invalid data.  In particular, this

		 * is true between the time a hardware scroll has been done

		 * and the time the structure WANT_CHAR would access has been

		 * updated.

		 */

		    int i;

#if USE_WIDEC_SUPPORT

#endif

			    ) {

			    ovw = FALSE;

			}

		    }

		}

		    int i;

								  from_x + i));

		}

		    hcost = lhcost;

		}

	    }

	} else {		/* (to_x < from_x) */

	    }

		int lhcost = 0;

#if USE_HARD_TABS

		if (init_tabs > 0 && back_tab) {

		    int nxt, fr;

		    for (fr = from_x; (nxt = LASTTAB(fr)) >= to_x; fr = nxt) {

			lhcost = repeated_append(&check, lhcost,

						 SP->_cbt_cost, 1, back_tab);

			if (lhcost == INFINITY)

			    break;

		    }

		    n = fr - to_x;

		}

#endif /* USE_HARD_TABS */

		    hcost = lhcost;

		}

	    }

	}

    }

}

#endif /* !NO_OPTIMIZE */

/*

 * With the machinery set up above, it's conceivable that

 * onscreen_mvcur could be modified into a recursive function that does

 * an alpha-beta search of motion space, as though it were a chess

 * move tree, with the weight function being boolean and the search

 * depth equated to length of string.  However, this would jack up the

 * computation cost a lot, especially on terminals without a cup

 * capability constraining the search tree depth.  So we settle for

 * the simpler method below.

 */

static NCURSES_INLINE int

onscreen_mvcur(int yold, int xold, int ynew, int xnew, bool ovw)

/* onscreen move from (yold, xold) to (ynew, xnew) */

{

    int tactic = 0, newcost, usecost = INFINITY;

    int t5_cr_cost;

#if defined(MAIN) || defined(NCURSES_TEST)

    struct timeval before, after;

    gettimeofday(&before, NULL);

#endif /* MAIN */

#define NullResult _nc_str_null(&result, sizeof(buffer))

#define InitResult _nc_str_init(&result, buffer, sizeof(buffer))

    /* tactic #0: use direct cursor addressing */

	tactic = 0;

#if defined(TRACE) || defined(NCURSES_TEST)

	if (!(_nc_optimize_enable & OPTIMIZE_MVCUR))

	    goto nonlocal;

#endif /* TRACE */

	/*

	 * We may be able to tell in advance that the full optimization

	 * will probably not be worth its overhead.  Also, don't try to

	 * use local movement if the current attribute is anything but

	 * A_NORMAL...there are just too many ways this can screw up

	 * (like, say, local-movement \n getting mapped to some obscure

	 * character because A_ALTCHARSET is on).

	 */

#if defined(MAIN) || defined(NCURSES_TEST)

	    if (!profiling) {

		(void) fputs("nonlocal\n", stderr);

		goto nonlocal;	/* always run the optimizer if profiling */

	    }

#else

	    goto nonlocal;

#endif /* MAIN */

	}

    }

#ifndef NO_OPTIMIZE

    /* tactic #1: use local movement */

	tactic = 1;

	usecost = newcost;

    }

    /* tactic #2: use carriage-return + local movement */

	tactic = 2;

	usecost = SP->_cr_cost + newcost;

    }

    /* tactic #3: use home-cursor + local movement */

	tactic = 3;

	usecost = SP->_home_cost + newcost;

    }

    /* tactic #4: use home-down + local movement */

	tactic = 4;

	usecost = SP->_ll_cost + newcost;

    }

    /*

     * tactic #5: use left margin for wrap to right-hand side,

     * unless strange wrap behavior indicated by xenl might hose us.

     */

	tactic = 5;

	usecost = t5_cr_cost + SP->_cub1_cost + newcost;

    }

    /*

     * These cases are ordered by estimated relative frequency.

     */

    case 1:

    case 2:

    case 3:

    case 4:

    case 5:

			     xnew, ovw);

    }

#endif /* !NO_OPTIMIZE */

  nonlocal:

#if defined(MAIN) || defined(NCURSES_TEST)

    gettimeofday(&after, NULL);

    diff = after.tv_usec - before.tv_usec

	+ (after.tv_sec - before.tv_sec) * 1000000;

    if (!profiling)

	(void) fprintf(stderr,

		       "onscreen: %d microsec, %f 28.8Kbps char-equivalents\n",

		       (int) diff, diff / 288);

#endif /* MAIN */

	TPUTS_TRACE("mvcur");

    } else

}

NCURSES_EXPORT(int)

mvcur(int yold, int xold, int ynew, int xnew)

/* optimized cursor move from (yold, xold) to (ynew, xnew) */

{

    int code;

    TR(TRACE_CALLS | TRACE_MOVE, (T_CALLED("mvcur(%d,%d,%d,%d)"),

				  yold, xold, ynew, xnew));

	code = ERR;

	code = OK;

	/*

	 * Most work here is rounding for terminal boundaries getting the

	 * column position implied by wraparound or the lack thereof and

	 * rolling up the screen to get ynew on the screen.

	 */

	}

	/*

	 * Force restore even if msgr is on when we're in an alternate

	 * character set -- these have a strong tendency to screw up the CR &

	 * LF used for local character motions!

	 */

	    TR(TRACE_CHARPUT, ("turning off (%#lx) %s before move",

			       (unsigned long) AttrOf(oldattr),

			       _traceattr(AttrOf(oldattr))));

	}

	    int l;

			TPUTS_TRACE("carriage_return");

		    xold = 0;

			    TPUTS_TRACE("newline");

		    }

		}

	    } else {

		/*

		 * If caller set nonl(), we cannot really use newlines to

		 * position to the next row.

		 */

		xold = -1;

		yold = -1;

	    }

	}

	/* destination location is on screen now */

	/*

	 * Restore attributes if we disabled them before moving.

	 */

	    TR(TRACE_CHARPUT, ("turning on (%#lx) %s after move",

			       (unsigned long) AttrOf(oldattr),

			       _traceattr(AttrOf(oldattr))));

	}

    }

}

#if defined(TRACE) || defined(NCURSES_TEST)

NCURSES_EXPORT_VAR(int) _nc_optimize_enable = OPTIMIZE_ALL;

#endif

#if defined(MAIN) || defined(NCURSES_TEST)

/****************************************************************************

 *

 * Movement optimizer test code

 *

 ****************************************************************************/

#include <tic.h>

#include <dump_entry.h>

#include <time.h>

NCURSES_EXPORT_VAR(const char *) _nc_progname = "mvcur";

static unsigned long xmits;

/* these override lib_tputs.c */

NCURSES_EXPORT(int)

tputs(const char *string, int affcnt GCC_UNUSED, int (*outc) (int) GCC_UNUSED)

/* stub tputs() that dumps sequences in a visible form */

{

    if (profiling)

	xmits += strlen(string);

    else

	(void) fputs(_nc_visbuf(string), stdout);

    return (OK);

}

NCURSES_EXPORT(int)

putp(const char *string)

{

    return (tputs(string, 1, _nc_outch));

}

NCURSES_EXPORT(int)

_nc_outch(int ch)

{