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lib_mvcur.c

/****************************************************************************
 * Copyright (c) 1998 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>                         *
 ****************************************************************************/


/*
**    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_lines - 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 1.50 1998/02/11 12:13:56 tom Exp $")

#define STRLEN(s)       (s != 0) ? strlen(s) : 0

#define CURRENT_ATTR    SP->_current_attr /* current phys attribute */
#define CURRENT_ROW     SP->_cursrow            /* phys cursor row */
#define CURRENT_COLUMN  SP->_curscol            /* phys cursor column */
#define REAL_ATTR SP->_current_attr /* phys current attribute */
#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", capname, result));
      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", capname, result));
      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

int _nc_msec_cost(const char *const cap, int affcnt)
/* compute the cost of a given operation */
{
    if (cap == 0)
      return(INFINITY);
    else
    {
      const char  *cp;
      float cum_cost = 0;

      for (cp = cap; *cp; cp++)
      {
          /* extract padding, either mandatory or required */
          if (cp[0] == '$' && cp[1] == '<' && strchr(cp, '>'))
          {
            float number = 0;

            for (cp += 2; *cp != '>'; cp++)
            {
                if (isdigit(*cp))
                  number = number * 10 + (*cp - '0');
                else if (*cp == '.')
                  number += (*++cp - 10) / 10.0;
                else if (*cp == '*')
                  number *= affcnt;
            }

            cum_cost += number * 10;
          }
          else
            cum_cost += SP->_char_padding;
      }

      return((int)cum_cost);
    }
}

static int normalized_cost(const char *const cap, int affcnt)
/* compute the effective character-count for an operation (round up) */
{
      int cost = _nc_msec_cost(cap, affcnt);
      if (cost != INFINITY)
            cost = (cost + SP->_char_padding - 1) / SP->_char_padding;
      return cost;
}

static void reset_scroll_region(void)
/* Set the scroll-region to a known state (the default) */
{
    if (change_scroll_region)
    {
      TPUTS_TRACE("change_scroll_region");
      putp(tparm(change_scroll_region, 0, screen_lines - 1));
    }
}

void _nc_mvcur_resume(void)
/* what to do at initialization time and after each shellout */
{
    /* initialize screen for cursor access */
    if (enter_ca_mode)
    {
      TPUTS_TRACE("enter_ca_mode");
      putp(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.
     */
    reset_scroll_region();
    SP->_cursrow = SP->_curscol = -1;
    
    /* restore cursor shape */
    if (SP->_cursor != -1)
    {
      int cursor = SP->_cursor;
      SP->_cursor = -1;
      curs_set (cursor);
    }
}

void _nc_mvcur_init(void)
/* initialize the cost structure */
{
    /*
     * 9 = 7 bits + 1 parity + 1 stop.
     */
    SP->_char_padding = (9 * 1000 * 10) / (BAUDRATE > 0 ? BAUDRATE : 9600);
    if (SP->_char_padding <= 0)
      SP->_char_padding = 1;  /* must be nonzero */
    TR(TRACE_CHARPUT|TRACE_MOVE, ("char_padding %d msecs", SP->_char_padding));

    /* non-parameterized local-motion strings */
    SP->_cr_cost   = CostOf(carriage_return, 0);
    SP->_home_cost = CostOf(cursor_home, 0);
    SP->_ll_cost   = CostOf(cursor_to_ll, 0);
#if USE_HARD_TABS
    SP->_ht_cost   = CostOf(tab, 0);
    SP->_cbt_cost  = CostOf(back_tab, 0);
#endif /* USE_HARD_TABS */
    SP->_cub1_cost = CostOf(cursor_left, 0);
    SP->_cuf1_cost = CostOf(cursor_right, 0);
    SP->_cud1_cost = CostOf(cursor_down, 0);
    SP->_cuu1_cost = CostOf(cursor_up, 0);

    /*
     * 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.
     */
    SP->_address_cursor = cursor_address ? cursor_address : cursor_mem_address;

    /*
     * 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.
     */
    SP->_cup_cost  = CostOf(tparm(SP->_address_cursor, 23, 23), 1);
    SP->_cub_cost  = CostOf(tparm(parm_left_cursor, 23), 1);
    SP->_cuf_cost  = CostOf(tparm(parm_right_cursor, 23), 1);
    SP->_cud_cost  = CostOf(tparm(parm_down_cursor, 23), 1);
    SP->_cuu_cost  = CostOf(tparm(parm_up_cursor, 23), 1);
    SP->_hpa_cost  = CostOf(tparm(column_address, 23), 1);
    SP->_vpa_cost  = CostOf(tparm(row_address, 23), 1);

    /* non-parameterized screen-update strings */
    SP->_ed_cost   = NormalizedCost(clr_eos, 1);
    SP->_el_cost   = NormalizedCost(clr_eol, 1);
    SP->_el1_cost  = NormalizedCost(clr_bol, 1);
    SP->_dch1_cost = NormalizedCost(delete_character, 1);
    SP->_ich1_cost = NormalizedCost(insert_character, 1);

    /* parameterized screen-update strings */
    SP->_dch_cost  = NormalizedCost(tparm(parm_dch, 23), 1);
    SP->_ich_cost  = NormalizedCost(tparm(parm_ich, 23), 1);
    SP->_ech_cost  = NormalizedCost(tparm(erase_chars, 23), 1);
    SP->_rep_cost  = NormalizedCost(tparm(repeat_char, ' ', 23), 1);

    SP->_cup_ch_cost = NormalizedCost(tparm(SP->_address_cursor, 23, 23), 1);
    SP->_hpa_ch_cost = NormalizedCost(tparm(column_address, 23), 1);

    /* pre-compute some capability lengths */
    SP->_carriage_return_length = STRLEN(carriage_return);
    SP->_cursor_home_length     = STRLEN(cursor_home);
    SP->_cursor_to_ll_length    = STRLEN(cursor_to_ll);

    /*
     * 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.
     */
    _nc_mvcur_resume();
}

void _nc_mvcur_wrap(void)
/* wrap up cursor-addressing mode */
{
    /* leave cursor at screen bottom */
    mvcur(-1, -1, screen_lines - 1, 0);

    /* set cursor to normal mode */
    if (SP->_cursor != -1)
      curs_set(1);

    if (exit_ca_mode)
    {
      TPUTS_TRACE("exit_ca_mode");
      putp(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.
     */
    _nc_outch('\r');
}

/****************************************************************************
 *
 * Optimized cursor movement
 *
 ****************************************************************************/

/*
 * Perform repeated-append, returning cost
 */
static inline int
repeated_append (int total, int num, int repeat, char *dst, const char *src)
{
      register size_t src_len = strlen(src);
      register size_t dst_len = STRLEN(dst);

      if ((dst_len + repeat * src_len) < OPT_SIZE-1) {
            total += (num * repeat);
            if (dst) {
                dst += dst_len;
                while (repeat-- > 0) {
                  (void) strcpy(dst, src);
                  dst += src_len;
                }
            }
      } else {
            total = INFINITY;
      }
      return total;
}

#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)

/* Note: we'd like to inline this for speed, but GNU C barfs on the attempt. */

static int
relative_move(char *result, 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;

    if (result)
      result[0] = '\0';

    if (to_y != from_y)
    {
      vcost = INFINITY;

      if (row_address)
      {
          if (result)
            (void) strcpy(result, tparm(row_address, to_y));
          vcost = SP->_vpa_cost;
      }

      if (to_y > from_y)
      {
          n = (to_y - from_y);

          if (parm_down_cursor && SP->_cud_cost < vcost)
          {
            if (result)
                (void) strcpy(result, tparm(parm_down_cursor, n));
            vcost = SP->_cud_cost;
          }

          if (cursor_down && (n * SP->_cud1_cost < vcost))
          {
            if (result)
                result[0] = '\0';
            vcost = repeated_append(0, SP->_cud1_cost, n, result, cursor_down);
          }
      }
      else /* (to_y < from_y) */
      {
          n = (from_y - to_y);

          if (parm_up_cursor && SP->_cup_cost < vcost)
          {
            if (result)
                (void) strcpy(result, tparm(parm_up_cursor, n));
            vcost = SP->_cup_cost;
          }

          if (cursor_up && (n * SP->_cuu1_cost < vcost))
          {
            if (result)
                result[0] = '\0';
            vcost = repeated_append(0, SP->_cuu1_cost, n, result, cursor_up);
          }
      }

      if (vcost == INFINITY)
          return(INFINITY);
    }

    if (result)
      result += strlen(result);

    if (to_x != from_x)
    {
      char  str[OPT_SIZE];

      hcost = INFINITY;

      if (column_address)
      {
          if (result)
            (void) strcpy(result, tparm(column_address, to_x));
          hcost = SP->_hpa_cost;
      }

      if (to_x > from_x)
      {
          n = to_x - from_x;

          if (parm_right_cursor && SP->_cuf_cost < hcost)
          {
            if (result)
                (void) strcpy(result, tparm(parm_right_cursor, n));
            hcost = SP->_cuf_cost;
          }

          if (cursor_right)
          {
            int   lhcost = 0;

            str[0] = '\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(lhcost, SP->_ht_cost, 1, str, tab);
                  if (lhcost == INFINITY)
                        break;
                }

                n = to_x - fr;
                from_x = fr;
            }
#endif /* USE_HARD_TABS */

#if defined(REAL_ATTR) && defined(WANT_CHAR)
            /*
             * 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.
             */
            if (ovw)
            {
                int     i;

                for (i = 0; i < n; i++)
                  if ((WANT_CHAR(to_y, from_x + i) & A_ATTRIBUTES) != CURRENT_ATTR)
                  {
                      ovw = FALSE;
                      break;
                  }
            }
            if (ovw)
            {
                char    *sp;
                int     i;

                sp = str + strlen(str);

                for (i = 0; i < n; i++)
                  *sp++ = WANT_CHAR(to_y, from_x + i);
                *sp = '\0';
                lhcost += n * SP->_char_padding;
              }
            else
#endif /* defined(REAL_ATTR) && defined(WANT_CHAR) */
            {
                lhcost = repeated_append(lhcost, SP->_cuf1_cost, n, str, cursor_right);
            }

            if (lhcost < hcost)
            {
                if (result)
                  (void) strcpy(result, str);
                hcost = lhcost;
            }
          }
      }
      else /* (to_x < from_x) */
      {
          n = from_x - to_x;

          if (parm_left_cursor && SP->_cub_cost < hcost)
          {
            if (result)
                (void) strcpy(result, tparm(parm_left_cursor, n));
            hcost = SP->_cub_cost;
          }

          if (cursor_left)
          {
            int   lhcost = 0;

            str[0] = '\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(lhcost, SP->_cbt_cost, 1, str, back_tab);
                  if (lhcost == INFINITY)
                        break;
                }

                n = fr - to_x;
            }
#endif /* USE_HARD_TABS */

            lhcost = repeated_append(lhcost, SP->_cub1_cost, n, str, cursor_left);

            if (lhcost < hcost)
            {
                if (result)
                  (void) strcpy(result, str);
                hcost = lhcost;
            }
          }
      }

      if (hcost == INFINITY)
          return(INFINITY);
    }

    return(vcost + hcost);
}
#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 inline int
onscreen_mvcur(int yold,int xold,int ynew,int xnew, bool ovw)
/* onscreen move from (yold, xold) to (ynew, xnew) */
{
    char    use[OPT_SIZE], *sp;
    int           tactic = 0, newcost, usecost = INFINITY;

#if defined(MAIN) || defined(NCURSES_TEST)
    struct timeval before, after;

    gettimeofday(&before, NULL);
#endif /* MAIN */

    /* tactic #0: use direct cursor addressing */
    sp = tparm(SP->_address_cursor, ynew, xnew);
    if (sp)
    {
      tactic = 0;
      (void) strcpy(use, sp);
      usecost = SP->_cup_cost;

#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 (yold == -1 || xold == -1 || NOT_LOCAL(yold, xold, ynew, xnew))
      {
#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 */
    if (yold != -1 && xold != -1
            && ((newcost=relative_move(NULL, yold, xold, ynew, xnew, ovw))!=INFINITY)
            && newcost < usecost)
    {
      tactic = 1;
      usecost = newcost;
    }

    /* tactic #2: use carriage-return + local movement */
    if (yold != -1 && carriage_return
            && ((newcost=relative_move(NULL, yold,0,ynew,xnew, ovw)) != INFINITY)
            && SP->_cr_cost + newcost < usecost)
    {
      tactic = 2;
      usecost = SP->_cr_cost + newcost;
    }

    /* tactic #3: use home-cursor + local movement */
    if (cursor_home
      && ((newcost=relative_move(NULL, 0, 0, ynew, xnew, ovw)) != INFINITY)
      && SP->_home_cost + newcost < usecost)
    {
      tactic = 3;
      usecost = SP->_home_cost + newcost;
    }

    /* tactic #4: use home-down + local movement */
    if (cursor_to_ll
      && ((newcost=relative_move(NULL, screen_lines-1, 0, ynew, xnew, ovw)) != INFINITY)
      && SP->_ll_cost + newcost < usecost)
    {
      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.
     */
    if (auto_left_margin && !eat_newline_glitch
      && yold > 0 && cursor_left
      && ((newcost=relative_move(NULL, yold-1, screen_columns-1, ynew, xnew, ovw)) != INFINITY)
      && SP->_cr_cost + SP->_cub1_cost + newcost + newcost < usecost)
    {
      tactic = 5;
      usecost = SP->_cr_cost + SP->_cub1_cost + newcost;
    }

    /*
     * These cases are ordered by estimated relative frequency.
     */
    if (tactic)
    {
      if (tactic == 1)
          (void) relative_move(use, yold, xold, ynew, xnew, ovw);
      else if (tactic == 2)
      {
          (void) strcpy(use, carriage_return);
          (void) relative_move(use + SP->_carriage_return_length,
                         yold,0,ynew,xnew, ovw);
      }
      else if (tactic == 3)
      {
          (void) strcpy(use, cursor_home);
          (void) relative_move(use + SP->_cursor_home_length,
                         0, 0, ynew, xnew, ovw);
      }
      else if (tactic == 4)
      {
          (void) strcpy(use, cursor_to_ll);
          (void) relative_move(use + SP->_cursor_to_ll_length,
                         screen_lines-1, 0, ynew, xnew, ovw);
      }
      else /* if (tactic == 5) */
      {
          use[0] = '\0';
          if (xold > 0)
            (void) strcat(use, carriage_return);
          (void) strcat(use, cursor_left);
          (void) relative_move(use + strlen(use),
                         yold-1, screen_columns-1, ynew, xnew, ovw);
      }
    }
#endif /* !NO_OPTIMIZE */

#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 msec, %f 28.8Kbps char-equivalents\n",
                   (int)diff, diff/288);
#endif /* MAIN */

 nonlocal:
    if (usecost != INFINITY)
    {
      TPUTS_TRACE("mvcur");
      tputs(use, 1, _nc_outch);
      return(OK);
    }
    else
      return(ERR);
}

int mvcur(int yold, int xold, int ynew, int xnew)
/* optimized cursor move from (yold, xold) to (ynew, xnew) */
{
    TR(TRACE_MOVE, ("mvcur(%d,%d,%d,%d) called", yold, xold, ynew, xnew));

    if (yold == ynew && xold == xnew)
      return(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.
     */

    if (xnew >= screen_columns)
    {
      ynew += xnew / screen_columns;
      xnew %= screen_columns;
    }
    if (xold >= screen_columns)
    {
      int   l;

      l = (xold + 1) / screen_columns;
      yold += l;
      if (yold >= screen_lines)
            l -= (yold - screen_lines - 1);

      while (l > 0) {
            if (newline)
            {
                  TPUTS_TRACE("newline");
                  tputs(newline, 0, _nc_outch);
            }
            else
                  putchar('\n');
            l--;
            if (xold > 0)
            {
                  if (carriage_return)
                  {
                        TPUTS_TRACE("carriage_return");
                        tputs(carriage_return, 0, _nc_outch);
                  }
                  else
                        putchar('\r');
                  xold = 0;
            }
      }
    }

    if (yold > screen_lines - 1)
      yold = screen_lines - 1;
    if (ynew > screen_lines - 1)
      ynew = screen_lines - 1;

    /* destination location is on screen now */
    return(onscreen_mvcur(yold, xold, ynew, xnew, TRUE));
}

#if defined(MAIN) || defined(NCURSES_TEST)
/****************************************************************************
 *
 * Movement optimizer test code
 *
 ****************************************************************************/

#include <tic.h>
#include <dump_entry.h>

const char *_nc_progname = "mvcur";

static unsigned long xmits;

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);
}

int putp(const char *string)
{
    return(tputs(string, 1, _nc_outch));
}

int _nc_outch(int ch)
{
    putc(ch, stdout);
    return OK;
}

static char tname[MAX_ALIAS];

static void load_term(void)
{
    (void) setupterm(tname, STDOUT_FILENO, NULL);
}

static int roll(int n)
{
    int i, j;

    i = (RAND_MAX / n) * n;
    while ((j = rand()) >= i)
      continue;
    return (j % n);
}

int main(int argc GCC_UNUSED, char *argv[] GCC_UNUSED)
{
    (void) strcpy(tname, termname());
    load_term();
    _nc_setupscreen(lines, columns, stdout);
    baudrate();

    _nc_mvcur_init();
#if HAVE_SETVBUF || HAVE_SETBUFFER
    /*
     * Undo the effects of our optimization hack, otherwise our interactive
     * prompts don't flush properly.
     */
#if HAVE_SETVBUF
    (void) setvbuf(SP->_ofp, malloc(BUFSIZ), _IOLBF, BUFSIZ);
#elif HAVE_SETBUFFER
    (void) setbuffer(SP->_ofp, malloc(BUFSIZ), BUFSIZ);
#endif
#endif /* HAVE_SETVBUF || HAVE_SETBUFFER */

    (void) puts("The mvcur tester.  Type ? for help");

    fputs("smcup:", stdout);
    putchar('\n');

    for (;;)
    {
      int   fy, fx, ty, tx, n, i;
      char  buf[BUFSIZ], capname[BUFSIZ];

      (void) fputs("> ", stdout);
      (void) fgets(buf, sizeof(buf), stdin);

      if (buf[0] == '?')
      {
(void) puts("?                -- display this help message");
(void) puts("fy fx ty tx      -- (4 numbers) display (fy,fx)->(ty,tx) move");
(void) puts("s[croll] n t b m -- display scrolling sequence");
(void) printf("r[eload]         -- reload terminal info for %s\n", termname());
(void) puts("l[oad] <term>    -- load terminal info for type <term>");
(void) puts("d[elete] <cap>   -- delete named capability");
(void) puts("i[nspect]        -- display terminal capabilities");
(void) puts("c[ost]           -- dump cursor-optimization cost table");
(void) puts("o[optimize]      -- toggle movement optimization");
(void) puts("t[orture] <num>  -- torture-test with <num> random moves");
(void) puts("q[uit]           -- quit the program");
      }
      else if (sscanf(buf, "%d %d %d %d", &fy, &fx, &ty, &tx) == 4)
      {
          struct timeval before, after;

          putchar('"');

          gettimeofday(&before, NULL);
          mvcur(fy, fx, ty, tx);
          gettimeofday(&after, NULL);

          printf("\" (%ld msec)\n",
            (long)(after.tv_usec - before.tv_usec + (after.tv_sec - before.tv_sec) * 1000000));
      }
      else if (sscanf(buf, "s %d %d %d %d", &fy, &fx, &ty, &tx) == 4)
      {
          struct timeval before, after;

          putchar('"');

          gettimeofday(&before, NULL);
          _nc_scrolln(fy, fx, ty, tx);
          gettimeofday(&after, NULL);

          printf("\" (%ld msec)\n",
            (long)(after.tv_usec - before.tv_usec + (after.tv_sec - before.tv_sec) * 1000000));
      }
      else if (buf[0] == 'r')
      {
          (void) strcpy(tname, termname());
          load_term();
      }
      else if (sscanf(buf, "l %s", tname) == 1)
      {
          load_term();
      }
      else if (sscanf(buf, "d %s", capname) == 1)
      {
          struct name_table_entry const   *np = _nc_find_entry(capname,
                                           _nc_info_hash_table);

          if (np == NULL)
            (void) printf("No such capability as \"%s\"\n", capname);
          else
          {
            switch(np->nte_type)
            {
            case BOOLEAN:
                cur_term->type.Booleans[np->nte_index] = FALSE;
                (void) printf("Boolean capability `%s' (%d) turned off.\n",
                          np->nte_name, np->nte_index);
                break;

            case NUMBER:
                cur_term->type.Numbers[np->nte_index] = -1;
                (void) printf("Number capability `%s' (%d) set to -1.\n",
                          np->nte_name, np->nte_index);
                break;

            case STRING:
                cur_term->type.Strings[np->nte_index] = (char *)NULL;
                (void) printf("String capability `%s' (%d) deleted.\n",
                          np->nte_name, np->nte_index);
                break;
            }
          }
      }
      else if (buf[0] == 'i')
      {
           dump_init((char *)NULL, F_TERMINFO, S_TERMINFO, 70, 0);
           dump_entry(&cur_term->type, 0, 0);
           putchar('\n');
      }
      else if (buf[0] == 'o')
      {
           if (_nc_optimize_enable & OPTIMIZE_MVCUR)
           {
             _nc_optimize_enable &=~ OPTIMIZE_MVCUR;
             (void) puts("Optimization is now off.");
           }
           else
           {
             _nc_optimize_enable |= OPTIMIZE_MVCUR;
             (void) puts("Optimization is now on.");
           }
      }
      /*
       * You can use the `t' test to profile and tune the movement
       * optimizer.  Use iteration values in three digits or more.
       * At above 5000 iterations the profile timing averages are stable
       * to within a millisecond or three.
       *
       * The `overhead' field of the report will help you pick a
       * COMPUTE_OVERHEAD figure appropriate for your processor and
       * expected line speed.  The `total estimated time' is
       * computation time plus a character-transmission time
       * estimate computed from the number of transmits and the baud
       * rate.
       *
       * Use this together with the `o' command to get a read on the
       * optimizer's effectiveness.  Compare the total estimated times
       * for `t' runs of the same length in both optimized and un-optimized
       * modes.  As long as the optimized times are less, the optimizer
       * is winning.
       */
      else if (sscanf(buf, "t %d", &n) == 1)
      {
          float cumtime = 0, perchar;
          int speeds[] = {2400, 9600, 14400, 19200, 28800, 38400, 0};

          srand((unsigned)(getpid() + time((time_t *)0)));
          profiling = TRUE;
          xmits = 0;
          for (i = 0; i < n; i++)
          {
            /*
             * This does a move test between two random locations,
             * Random moves probably short-change the optimizer,
             * which will work better on the short moves probably
             * typical of doupdate()'s usage pattern.  Still,
             * until we have better data...
             */
#ifdef FIND_COREDUMP
            int from_y = roll(lines);
            int to_y = roll(lines);
            int from_x = roll(columns);
            int to_x = roll(columns);

            printf("(%d,%d) -> (%d,%d)\n", from_y, from_x, to_y, to_x);
            mvcur(from_y, from_x, to_y, to_x);
#else
            mvcur(roll(lines), roll(columns), roll(lines), roll(columns));
#endif /* FIND_COREDUMP */
            if (diff)
                cumtime += diff;
          }
          profiling = FALSE;

          /*
           * Average milliseconds per character optimization time.
           * This is the key figure to watch when tuning the optimizer.
           */
          perchar = cumtime / n;

          (void) printf("%d moves (%ld chars) in %d msec, %f msec each:\n",
                    n, xmits, (int)cumtime, perchar);

          for (i = 0; speeds[i]; i++)
          {
            /*
             * Total estimated time for the moves, computation and
             * transmission both. Transmission time is an estimate
             * assuming 9 bits/char, 8 bits + 1 stop bit.
             */
            float totalest = cumtime + xmits * 9 * 1e6 / speeds[i];

            /*
             * Per-character optimization overhead in character transmits
             * at the current speed.  Round this to the nearest integer
             * to figure COMPUTE_OVERHEAD for the speed.
             */
            float overhead = speeds[i] * perchar / 1e6;

            (void) printf("%6d bps: %3.2f char-xmits overhead; total estimated time %15.2f\n",
                        speeds[i], overhead, totalest);
          }
      }
      else if (buf[0] == 'c')
      {
          (void) printf("char padding: %d\n", SP->_char_padding);
          (void) printf("cr cost: %d\n", SP->_cr_cost);
          (void) printf("cup cost: %d\n", SP->_cup_cost);
          (void) printf("home cost: %d\n", SP->_home_cost);
          (void) printf("ll cost: %d\n", SP->_ll_cost);
#if USE_HARD_TABS
          (void) printf("ht cost: %d\n", SP->_ht_cost);
          (void) printf("cbt cost: %d\n", SP->_cbt_cost);
#endif /* USE_HARD_TABS */
          (void) printf("cub1 cost: %d\n", SP->_cub1_cost);
          (void) printf("cuf1 cost: %d\n", SP->_cuf1_cost);
          (void) printf("cud1 cost: %d\n", SP->_cud1_cost);
          (void) printf("cuu1 cost: %d\n", SP->_cuu1_cost);
          (void) printf("cub cost: %d\n", SP->_cub_cost);
          (void) printf("cuf cost: %d\n", SP->_cuf_cost);
          (void) printf("cud cost: %d\n", SP->_cud_cost);
          (void) printf("cuu cost: %d\n", SP->_cuu_cost);
          (void) printf("hpa cost: %d\n", SP->_hpa_cost);
          (void) printf("vpa cost: %d\n", SP->_vpa_cost);
      }
      else if (buf[0] == 'x' || buf[0] == 'q')
          break;
      else
          (void) puts("Invalid command.");
    }

    (void) fputs("rmcup:", stdout);
    _nc_mvcur_wrap();
    putchar('\n');

    return(0);
}

#endif /* MAIN */

/* lib_mvcur.c ends here */

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