lib_mvcur.c

ncurses 库 可能有用酒用 没用就算了 我觉得还可以用

NCURSES_EXPORT(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(string_desc * target, int total, int num, int repeat, const char *src)
{
    size_t need = repeat * strlen(src);

    if (need < target->s_size) {
	while (repeat-- > 0) {
	    if (_nc_safe_strcat(target, src)) {
		total += num;
	    } else {
		total = INFINITY;
		break;
	    }
	}
    } 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)

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) */
{
    string_desc save;
    int n, vcost = 0, hcost = 0;

    (void) _nc_str_copy(&save, target);

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

	if (row_address != 0
	    && _nc_safe_strcat(target, 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
		&& _nc_safe_strcat(_nc_str_copy(target, &save),
				   tparm(parm_down_cursor, n))) {
		vcost = SP->_cud_cost;
	    }

	    if (cursor_down
		&& (*cursor_down != '\n' || SP->_nl)
		&& (n * SP->_cud1_cost < vcost)) {
		vcost = repeated_append(_nc_str_copy(target, &save), 0,
					SP->_cud1_cost, n, cursor_down);
	    }
	} else {		/* (to_y < from_y) */
	    n = (from_y - to_y);

	    if (parm_up_cursor
		&& SP->_cuu_cost < vcost
		&& _nc_safe_strcat(_nc_str_copy(target, &save),
				   tparm(parm_up_cursor, n))) {
		vcost = SP->_cuu_cost;
	    }

	    if (cursor_up && (n * SP->_cuu1_cost < vcost)) {
		vcost = repeated_append(_nc_str_copy(target, &save), 0,
					SP->_cuu1_cost, n, cursor_up);
	    }
	}

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

    save = *target;

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

	hcost = INFINITY;

	if (column_address
	    && _nc_safe_strcat(_nc_str_copy(target, &save),
			       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
		&& _nc_safe_strcat(_nc_str_copy(target, &save),
				   tparm(parm_right_cursor, n))) {
		hcost = SP->_cuf_cost;
	    }

	    if (cursor_right) {
		int lhcost = 0;

		(void) _nc_str_init(&check, str, sizeof(str));

#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 (n <= 0 || n >= (int) check.s_size)
		    ovw = FALSE;
#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.
		 */
		if (ovw
		    && n > 0
		    && n < (int) check.s_size
		    && vcost == 0
		    && str[0] == '\0') {
		    int wanted = CharOf(WANT_CHAR(to_y, from_x));
		    if (is8bits(wanted) && isdigit(wanted))
			ovw = FALSE;
		}
#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.
		 */
		if (ovw) {
		    int i;

		    for (i = 0; i < n; i++) {
			NCURSES_CH_T ch = WANT_CHAR(to_y, from_x + i);
			if (!SameAttrOf(ch, SCREEN_ATTRS(SP))
#if USE_WIDEC_SUPPORT
			    || !Charable(ch)
#endif
			    ) {
			    ovw = FALSE;
			    break;
			}
		    }
		}
		if (ovw) {
		    int i;

		    for (i = 0; i < n; i++)
			*check.s_tail++ = CharOf(WANT_CHAR(to_y, from_x + i));
		    *check.s_tail = '\0';
		    check.s_size -= n;
		    lhcost += n * SP->_char_padding;
		} else {
		    lhcost = repeated_append(&check, lhcost, SP->_cuf1_cost,
					     n, cursor_right);
		}

		if (lhcost < hcost
		    && _nc_safe_strcat(_nc_str_copy(target, &save), str)) {
		    hcost = lhcost;
		}
	    }
	} else {		/* (to_x < from_x) */
	    n = from_x - to_x;

	    if (parm_left_cursor
		&& SP->_cub_cost < hcost
		&& _nc_safe_strcat(_nc_str_copy(target, &save),
				   tparm(parm_left_cursor, n))) {
		hcost = SP->_cub_cost;
	    }

	    if (cursor_left) {
		int lhcost = 0;

		(void) _nc_str_init(&check, str, sizeof(str));

#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 */

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

		if (lhcost < hcost
		    && _nc_safe_strcat(_nc_str_copy(target, &save), 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) */
{
    string_desc result;
    char buffer[OPT_SIZE];
    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 */
    if (_nc_safe_strcpy(InitResult, tparm(SP->_address_cursor, ynew, xnew))) {
	tactic = 0;
	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(NullResult, 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(NullResult, 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(NullResult, 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(NullResult, 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.
     */
    t5_cr_cost = (xold > 0 ? SP->_cr_cost : 0);
    if (auto_left_margin && !eat_newline_glitch
	&& yold > 0 && cursor_left
	&& ((newcost = relative_move(NullResult, yold - 1, screen_columns -
				     1, ynew, xnew, ovw)) != INFINITY)
	&& t5_cr_cost + SP->_cub1_cost + newcost < usecost) {
	tactic = 5;
	usecost = t5_cr_cost + SP->_cub1_cost + newcost;
    }

    /*
     * These cases are ordered by estimated relative frequency.
     */
    if (tactic)
	InitResult;
    switch (tactic) {
    case 1:
	(void) relative_move(&result, yold, xold, ynew, xnew, ovw);
	break;
    case 2:
	(void) _nc_safe_strcpy(&result, carriage_return);
	(void) relative_move(&result, yold, 0, ynew, xnew, ovw);
	break;
    case 3:
	(void) _nc_safe_strcpy(&result, cursor_home);
	(void) relative_move(&result, 0, 0, ynew, xnew, ovw);
	break;
    case 4:
	(void) _nc_safe_strcpy(&result, cursor_to_ll);
	(void) relative_move(&result, screen_lines - 1, 0, ynew, xnew, ovw);
	break;
    case 5:
	if (xold > 0)
	    (void) _nc_safe_strcat(&result, carriage_return);
	(void) _nc_safe_strcat(&result, cursor_left);
	(void) relative_move(&result, yold - 1, screen_columns - 1, ynew,
			     xnew, ovw);
	break;
    }
#endif /* !NO_OPTIMIZE */

  nonlocal:
#if defined(MAIN) || defined(NCURSES_TEST)
    gettimeofday(&after, NULL);