/* vi:set ts=8 sts=4 sw=4 noet:
 *
 * VIM - Vi IMproved	by Bram Moolenaar
 *
 * Do ":help uganda"  in Vim to read copying and usage conditions.
 * Do ":help credits" in Vim to see a list of people who contributed.
 * See README.txt for an overview of the Vim source code.
 */

/*
 * indent.c: Indentation related functions
 */

#include "vim.h"

#if defined(FEAT_VARTABS) || defined(PROTO)

/*
 * Set the integer values corresponding to the string setting of 'vartabstop'.
 * "array" will be set, caller must free it if needed.
 */
    int
tabstop_set(char_u *var, int **array)
{
    int valcount = 1;
    int t;
    char_u *cp;

    if (var[0] == NUL || (var[0] == '0' && var[1] == NUL))
    {
	*array = NULL;
	return TRUE;
    }

    for (cp = var; *cp != NUL; ++cp)
    {
	if (cp == var || cp[-1] == ',')
	{
	    char_u *end;

	    if (strtol((char *)cp, (char **)&end, 10) <= 0)
	    {
		if (cp != end)
		    emsg(_(e_positive));
		else
		    emsg(_(e_invarg));
		return FALSE;
	    }
	}

	if (VIM_ISDIGIT(*cp))
	    continue;
	if (cp[0] == ',' && cp > var && cp[-1] != ',' && cp[1] != NUL)
	{
	    ++valcount;
	    continue;
	}
	emsg(_(e_invarg));
	return FALSE;
    }

    *array = ALLOC_MULT(int, valcount + 1);
    if (*array == NULL)
	return FALSE;
    (*array)[0] = valcount;

    t = 1;
    for (cp = var; *cp != NUL;)
    {
	(*array)[t++] = atoi((char *)cp);
	while (*cp  != NUL && *cp != ',')
	    ++cp;
	if (*cp != NUL)
	    ++cp;
    }

    return TRUE;
}

/*
 * Calculate the number of screen spaces a tab will occupy.
 * If "vts" is set then the tab widths are taken from that array,
 * otherwise the value of ts is used.
 */
    int
tabstop_padding(colnr_T col, int ts_arg, int *vts)
{
    int		ts = ts_arg == 0 ? 8 : ts_arg;
    int		tabcount;
    colnr_T	tabcol = 0;
    int		t;
    int		padding = 0;

    if (vts == NULL || vts[0] == 0)
	return ts - (col % ts);

    tabcount = vts[0];

    for (t = 1; t <= tabcount; ++t)
    {
	tabcol += vts[t];
	if (tabcol > col)
	{
	    padding = (int)(tabcol - col);
	    break;
	}
    }
    if (t > tabcount)
	padding = vts[tabcount] - (int)((col - tabcol) % vts[tabcount]);

    return padding;
}

/*
 * Find the size of the tab that covers a particular column.
 */
    int
tabstop_at(colnr_T col, int ts, int *vts)
{
    int		tabcount;
    colnr_T	tabcol = 0;
    int		t;
    int		tab_size = 0;

    if (vts == 0 || vts[0] == 0)
	return ts;

    tabcount = vts[0];
    for (t = 1; t <= tabcount; ++t)
    {
	tabcol += vts[t];
	if (tabcol > col)
	{
	    tab_size = vts[t];
	    break;
	}
    }
    if (t > tabcount)
	tab_size = vts[tabcount];

    return tab_size;
}

/*
 * Find the column on which a tab starts.
 */
    colnr_T
tabstop_start(colnr_T col, int ts, int *vts)
{
    int		tabcount;
    colnr_T	tabcol = 0;
    int		t;
    int         excess;

    if (vts == NULL || vts[0] == 0)
	return (col / ts) * ts;

    tabcount = vts[0];
    for (t = 1; t <= tabcount; ++t)
    {
	tabcol += vts[t];
	if (tabcol > col)
	    return tabcol - vts[t];
    }

    excess = tabcol % vts[tabcount];
    return excess + ((col - excess) / vts[tabcount]) * vts[tabcount];
}

/*
 * Find the number of tabs and spaces necessary to get from one column
 * to another.
 */
    void
tabstop_fromto(
	colnr_T start_col,
	colnr_T end_col,
	int	ts_arg,
	int	*vts,
	int	*ntabs,
	int	*nspcs)
{
    int		spaces = end_col - start_col;
    colnr_T	tabcol = 0;
    int		padding = 0;
    int		tabcount;
    int		t;
    int		ts = ts_arg == 0 ? curbuf->b_p_ts : ts_arg;

    if (vts == NULL || vts[0] == 0)
    {
	int tabs = 0;
	int initspc = 0;

	initspc = ts - (start_col % ts);
	if (spaces >= initspc)
	{
	    spaces -= initspc;
	    tabs++;
	}
	tabs += spaces / ts;
	spaces -= (spaces / ts) * ts;

	*ntabs = tabs;
	*nspcs = spaces;
	return;
    }

    // Find the padding needed to reach the next tabstop.
    tabcount = vts[0];
    for (t = 1; t <= tabcount; ++t)
    {
	tabcol += vts[t];
	if (tabcol > start_col)
	{
	    padding = (int)(tabcol - start_col);
	    break;
	}
    }
    if (t > tabcount)
	padding = vts[tabcount] - (int)((start_col - tabcol) % vts[tabcount]);

    // If the space needed is less than the padding no tabs can be used.
    if (spaces < padding)
    {
	*ntabs = 0;
	*nspcs = spaces;
	return;
    }

    *ntabs = 1;
    spaces -= padding;

    // At least one tab has been used. See if any more will fit.
    while (spaces != 0 && ++t <= tabcount)
    {
	padding = vts[t];
	if (spaces < padding)
	{
	    *nspcs = spaces;
	    return;
	}
	++*ntabs;
	spaces -= padding;
    }

    *ntabs += spaces / vts[tabcount];
    *nspcs =  spaces % vts[tabcount];
}

/*
 * See if two tabstop arrays contain the same values.
 */
    static int
tabstop_eq(int *ts1, int *ts2)
{
    int		t;

    if ((ts1 == 0 && ts2) || (ts1 && ts2 == 0))
	return FALSE;
    if (ts1 == ts2)
	return TRUE;
    if (ts1[0] != ts2[0])
	return FALSE;

    for (t = 1; t <= ts1[0]; ++t)
	if (ts1[t] != ts2[t])
	    return FALSE;

    return TRUE;
}

# if defined(FEAT_BEVAL) || defined(PROTO)
/*
 * Copy a tabstop array, allocating space for the new array.
 */
    int *
tabstop_copy(int *oldts)
{
    int		*newts;
    int		t;

    if (oldts == NULL)
	return NULL;
    newts = ALLOC_MULT(int, oldts[0] + 1);
    if (newts != NULL)
	for (t = 0; t <= oldts[0]; ++t)
	    newts[t] = oldts[t];
    return newts;
}
# endif

/*
 * Return a count of the number of tabstops.
 */
    int
tabstop_count(int *ts)
{
    return ts != NULL ? ts[0] : 0;
}

/*
 * Return the first tabstop, or 8 if there are no tabstops defined.
 */
    int
tabstop_first(int *ts)
{
    return ts != NULL ? ts[1] : 8;
}

#endif

/*
 * Return the effective shiftwidth value for current buffer, using the
 * 'tabstop' value when 'shiftwidth' is zero.
 */
    long
get_sw_value(buf_T *buf)
{
    return get_sw_value_col(buf, 0);
}

/*
 * Idem, using "pos".
 */
    static long
get_sw_value_pos(buf_T *buf, pos_T *pos)
{
    pos_T save_cursor = curwin->w_cursor;
    long sw_value;

    curwin->w_cursor = *pos;
    sw_value = get_sw_value_col(buf, get_nolist_virtcol());
    curwin->w_cursor = save_cursor;
    return sw_value;
}

/*
 * Idem, using the first non-black in the current line.
 */
    long
get_sw_value_indent(buf_T *buf)
{
    pos_T pos = curwin->w_cursor;

    pos.col = getwhitecols_curline();
    return get_sw_value_pos(buf, &pos);
}

/*
 * Idem, using virtual column "col".
 */
    long
get_sw_value_col(buf_T *buf, colnr_T col UNUSED)
{
    return buf->b_p_sw ? buf->b_p_sw :
#ifdef FEAT_VARTABS
	tabstop_at(col, buf->b_p_ts, buf->b_p_vts_array);
#else
	buf->b_p_ts;
#endif
}

/*
 * Return the effective softtabstop value for the current buffer, using the
 * 'shiftwidth' value when 'softtabstop' is negative.
 */
    long
get_sts_value(void)
{
    return curbuf->b_p_sts < 0 ? get_sw_value(curbuf) : curbuf->b_p_sts;
}

/*
 * Count the size (in window cells) of the indent in the current line.
 */
    int
get_indent(void)
{
#ifdef FEAT_VARTABS
    return get_indent_str_vtab(ml_get_curline(), (int)curbuf->b_p_ts,
						 curbuf->b_p_vts_array, FALSE);
#else
    return get_indent_str(ml_get_curline(), (int)curbuf->b_p_ts, FALSE);
#endif
}

/*
 * Count the size (in window cells) of the indent in line "lnum".
 */
    int
get_indent_lnum(linenr_T lnum)
{
#ifdef FEAT_VARTABS
    return get_indent_str_vtab(ml_get(lnum), (int)curbuf->b_p_ts,
						 curbuf->b_p_vts_array, FALSE);
#else
    return get_indent_str(ml_get(lnum), (int)curbuf->b_p_ts, FALSE);
#endif
}

#if defined(FEAT_FOLDING) || defined(PROTO)
/*
 * Count the size (in window cells) of the indent in line "lnum" of buffer
 * "buf".
 */
    int
get_indent_buf(buf_T *buf, linenr_T lnum)
{
# ifdef FEAT_VARTABS
    return get_indent_str_vtab(ml_get_buf(buf, lnum, FALSE),
			       (int)curbuf->b_p_ts, buf->b_p_vts_array, FALSE);
# else
    return get_indent_str(ml_get_buf(buf, lnum, FALSE), (int)buf->b_p_ts, FALSE);
# endif
}
#endif

/*
 * count the size (in window cells) of the indent in line "ptr", with
 * 'tabstop' at "ts"
 */
    int
get_indent_str(
    char_u	*ptr,
    int		ts,
    int		list) // if TRUE, count only screen size for tabs
{
    int		count = 0;

    for ( ; *ptr; ++ptr)
    {
	if (*ptr == TAB)
	{
	    if (!list || lcs_tab1)    // count a tab for what it is worth
		count += ts - (count % ts);
	    else
		// In list mode, when tab is not set, count screen char width
		// for Tab, displays: ^I
		count += ptr2cells(ptr);
	}
	else if (*ptr == ' ')
	    ++count;		// count a space for one
	else
	    break;
    }
    return count;
}

#ifdef FEAT_VARTABS
/*
 * Count the size (in window cells) of the indent in line "ptr", using
 * variable tabstops.
 * if "list" is TRUE, count only screen size for tabs.
 */
    int
get_indent_str_vtab(char_u *ptr, int ts, int *vts, int list)
{
    int		count = 0;

    for ( ; *ptr; ++ptr)
    {
	if (*ptr == TAB)    // count a tab for what it is worth
	{
	    if (!list || lcs_tab1)
		count += tabstop_padding(count, ts, vts);
	    else
		// In list mode, when tab is not set, count screen char width
		// for Tab, displays: ^I
		count += ptr2cells(ptr);
	}
	else if (*ptr == ' ')
	    ++count;		// count a space for one
	else
	    break;
    }
    return count;
}
#endif

/*
 * Set the indent of the current line.
 * Leaves the cursor on the first non-blank in the line.
 * Caller must take care of undo.
 * "flags":
 *	SIN_CHANGED:	call changed_bytes() if the line was changed.
 *	SIN_INSERT:	insert the indent in front of the line.
 *	SIN_UNDO:	save line for undo before changing it.
 * Returns TRUE if the line was changed.
 */
    int
set_indent(
    int		size,		    // measured in spaces
    int		flags)
{
    char_u	*p;
    char_u	*newline;
    char_u	*oldline;
    char_u	*s;
    int		todo;
    int		ind_len;	    // measured in characters
    int		line_len;
    int		doit = FALSE;
    int		ind_done = 0;	    // measured in spaces
#ifdef FEAT_VARTABS
    int		ind_col = 0;
#endif
    int		tab_pad;
    int		retval = FALSE;
    int		orig_char_len = -1; // number of initial whitespace chars when
				    // 'et' and 'pi' are both set

    // First check if there is anything to do and compute the number of
    // characters needed for the indent.
    todo = size;
    ind_len = 0;
    p = oldline = ml_get_curline();

    // Calculate the buffer size for the new indent, and check to see if it
    // isn't already set

    // if 'expandtab' isn't set: use TABs; if both 'expandtab' and
    // 'preserveindent' are set count the number of characters at the
    // beginning of the line to be copied
    if (!curbuf->b_p_et || (!(flags & SIN_INSERT) && curbuf->b_p_pi))
    {
	// If 'preserveindent' is set then reuse as much as possible of
	// the existing indent structure for the new indent
	if (!(flags & SIN_INSERT) && curbuf->b_p_pi)
	{
	    ind_done = 0;

	    // count as many characters as we can use
	    while (todo > 0 && VIM_ISWHITE(*p))
	    {
		if (*p == TAB)
		{
#ifdef FEAT_VARTABS
		    tab_pad = tabstop_padding(ind_done, curbuf->b_p_ts,
							curbuf->b_p_vts_array);
#else
		    tab_pad = (int)curbuf->b_p_ts
					   - (ind_done % (int)curbuf->b_p_ts);
#endif
		    // stop if this tab will overshoot the target
		    if (todo < tab_pad)
			break;
		    todo -= tab_pad;
		    ++ind_len;
		    ind_done += tab_pad;
		}
		else
		{
		    --todo;
		    ++ind_len;
		    ++ind_done;
		}
		++p;
	    }

#ifdef FEAT_VARTABS
	    // These diverge from this point.
	    ind_col = ind_done;
#endif
	    // Set initial number of whitespace chars to copy if we are
	    // preserving indent but expandtab is set
	    if (curbuf->b_p_et)
		orig_char_len = ind_len;

	    // Fill to next tabstop with a tab, if possible
#ifdef FEAT_VARTABS
	    tab_pad = tabstop_padding(ind_done, curbuf->b_p_ts,
						curbuf->b_p_vts_array);
#else
	    tab_pad = (int)curbuf->b_p_ts - (ind_done % (int)curbuf->b_p_ts);
#endif
	    if (todo >= tab_pad && orig_char_len == -1)
	    {
		doit = TRUE;
		todo -= tab_pad;
		++ind_len;
		// ind_done += tab_pad;
#ifdef FEAT_VARTABS
		ind_col += tab_pad;
#endif
	    }
	}

	// count tabs required for indent
#ifdef FEAT_VARTABS
	for (;;)
	{
	    tab_pad = tabstop_padding(ind_col, curbuf->b_p_ts,
							curbuf->b_p_vts_array);
	    if (todo < tab_pad)
		break;
	    if (*p != TAB)
		doit = TRUE;
	    else
		++p;
	    todo -= tab_pad;
	    ++ind_len;
	    ind_col += tab_pad;
	}
#else
	while (todo >= (int)curbuf->b_p_ts)
	{
	    if (*p != TAB)
		doit = TRUE;
	    else
		++p;
	    todo -= (int)curbuf->b_p_ts;
	    ++ind_len;
	    // ind_done += (int)curbuf->b_p_ts;
	}
#endif
    }
    // count spaces required for indent
    while (todo > 0)
    {
	if (*p != ' ')
	    doit = TRUE;
	else
	    ++p;
	--todo;
	++ind_len;
	// ++ind_done;
    }

    // Return if the indent is OK already.
    if (!doit && !VIM_ISWHITE(*p) && !(flags & SIN_INSERT))
	return FALSE;

    // Allocate memory for the new line.
    if (flags & SIN_INSERT)
	p = oldline;
    else
	p = skipwhite(p);
    line_len = (int)STRLEN(p) + 1;

    // If 'preserveindent' and 'expandtab' are both set keep the original
    // characters and allocate accordingly.  We will fill the rest with spaces
    // after the if (!curbuf->b_p_et) below.
    if (orig_char_len != -1)
    {
	newline = alloc(orig_char_len + size - ind_done + line_len);
	if (newline == NULL)
	    return FALSE;
	todo = size - ind_done;
	ind_len = orig_char_len + todo;    // Set total length of indent in
					   // characters, which may have been
					   // undercounted until now
	p = oldline;
	s = newline;
	while (orig_char_len > 0)
	{
	    *s++ = *p++;
	    orig_char_len--;
	}

	// Skip over any additional white space (useful when newindent is less
	// than old)
	while (VIM_ISWHITE(*p))
	    ++p;

    }
    else
    {
	todo = size;
	newline = alloc(ind_len + line_len);
	if (newline == NULL)
	    return FALSE;
	s = newline;
    }

    // Put the characters in the new line.
    // if 'expandtab' isn't set: use TABs
    if (!curbuf->b_p_et)
    {
	// If 'preserveindent' is set then reuse as much as possible of
	// the existing indent structure for the new indent
	if (!(flags & SIN_INSERT) && curbuf->b_p_pi)
	{
	    p = oldline;
	    ind_done = 0;

	    while (todo > 0 && VIM_ISWHITE(*p))
	    {
		if (*p == TAB)
		{
#ifdef FEAT_VARTABS
		    tab_pad = tabstop_padding(ind_done, curbuf->b_p_ts,
							curbuf->b_p_vts_array);
#else
		    tab_pad = (int)curbuf->b_p_ts
					   - (ind_done % (int)curbuf->b_p_ts);
#endif
		    // stop if this tab will overshoot the target
		    if (todo < tab_pad)
			break;
		    todo -= tab_pad;
		    ind_done += tab_pad;
		}
		else
		{
		    --todo;
		    ++ind_done;
		}
		*s++ = *p++;
	    }

	    // Fill to next tabstop with a tab, if possible
#ifdef FEAT_VARTABS
	    tab_pad = tabstop_padding(ind_done, curbuf->b_p_ts,
						curbuf->b_p_vts_array);
#else
	    tab_pad = (int)curbuf->b_p_ts - (ind_done % (int)curbuf->b_p_ts);
#endif
	    if (todo >= tab_pad)
	    {
		*s++ = TAB;
		todo -= tab_pad;
#ifdef FEAT_VARTABS
		ind_done += tab_pad;
#endif
	    }

	    p = skipwhite(p);
	}

#ifdef FEAT_VARTABS
	for (;;)
	{
	    tab_pad = tabstop_padding(ind_done, curbuf->b_p_ts,
							curbuf->b_p_vts_array);
	    if (todo < tab_pad)
		break;
	    *s++ = TAB;
	    todo -= tab_pad;
	    ind_done += tab_pad;
	}
#else
	while (todo >= (int)curbuf->b_p_ts)
	{
	    *s++ = TAB;
	    todo -= (int)curbuf->b_p_ts;
	}
#endif
    }
    while (todo > 0)
    {
	*s++ = ' ';
	--todo;
    }
    mch_memmove(s, p, (size_t)line_len);

    // Replace the line (unless undo fails).
    if (!(flags & SIN_UNDO) || u_savesub(curwin->w_cursor.lnum) == OK)
    {
	ml_replace(curwin->w_cursor.lnum, newline, FALSE);
	if (flags & SIN_CHANGED)
	    changed_bytes(curwin->w_cursor.lnum, 0);

	// Correct saved cursor position if it is in this line.
	if (saved_cursor.lnum == curwin->w_cursor.lnum)
	{
	    if (saved_cursor.col >= (colnr_T)(p - oldline))
		// cursor was after the indent, adjust for the number of
		// bytes added/removed
		saved_cursor.col += ind_len - (colnr_T)(p - oldline);
	    else if (saved_cursor.col >= (colnr_T)(s - newline))
		// cursor was in the indent, and is now after it, put it back
		// at the start of the indent (replacing spaces with TAB)
		saved_cursor.col = (colnr_T)(s - newline);
	}
#ifdef FEAT_TEXT_PROP
	{
	    int added = ind_len - (colnr_T)(p - oldline);

	    // When increasing indent this behaves like spaces were inserted at
	    // the old indent, when decreasing indent it behaves like spaces
	    // were deleted at the new indent.
	    adjust_prop_columns(curwin->w_cursor.lnum,
		 (colnr_T)(added > 0 ? (p - oldline) : ind_len), added, 0);
	}
#endif
	retval = TRUE;
    }
    else
	vim_free(newline);

    curwin->w_cursor.col = ind_len;
    return retval;
}

/*
 * Return the indent of the current line after a number.  Return -1 if no
 * number was found.  Used for 'n' in 'formatoptions': numbered list.
 * Since a pattern is used it can actually handle more than numbers.
 */
    int
get_number_indent(linenr_T lnum)
{
    colnr_T	col;
    pos_T	pos;

    regmatch_T	regmatch;
    int		lead_len = 0;	// length of comment leader

    if (lnum > curbuf->b_ml.ml_line_count)
	return -1;
    pos.lnum = 0;

    // In format_lines() (i.e. not insert mode), fo+=q is needed too...
    if ((State & INSERT) || has_format_option(FO_Q_COMS))
	lead_len = get_leader_len(ml_get(lnum), NULL, FALSE, TRUE);

    regmatch.regprog = vim_regcomp(curbuf->b_p_flp, RE_MAGIC);
    if (regmatch.regprog != NULL)
    {
	regmatch.rm_ic = FALSE;

	// vim_regexec() expects a pointer to a line.  This lets us
	// start matching for the flp beyond any comment leader...
	if (vim_regexec(&regmatch, ml_get(lnum) + lead_len, (colnr_T)0))
	{
	    pos.lnum = lnum;
	    pos.col = (colnr_T)(*regmatch.endp - ml_get(lnum));
	    pos.coladd = 0;
	}
	vim_regfree(regmatch.regprog);
    }

    if (pos.lnum == 0 || *ml_get_pos(&pos) == NUL)
	return -1;
    getvcol(curwin, &pos, &col, NULL, NULL);
    return (int)col;
}

#if defined(FEAT_LINEBREAK) || defined(PROTO)
/*
 * Return appropriate space number for breakindent, taking influencing
 * parameters into account. Window must be specified, since it is not
 * necessarily always the current one.
 */
    int
get_breakindent_win(
    win_T	*wp,
    char_u	*line) // start of the line
{
    static int	    prev_indent = 0;  // cached indent value
    static long	    prev_ts     = 0L; // cached tabstop value
    static char_u   *prev_line = NULL; // cached pointer to line
    static varnumber_T prev_tick = 0;   // changedtick of cached value
# ifdef FEAT_VARTABS
    static int      *prev_vts = NULL;    // cached vartabs values
# endif
    int		    bri = 0;
    // window width minus window margin space, i.e. what rests for text
    const int	    eff_wwidth = wp->w_width
			    - ((wp->w_p_nu || wp->w_p_rnu)
				&& (vim_strchr(p_cpo, CPO_NUMCOL) == NULL)
						? number_width(wp) + 1 : 0);

    // used cached indent, unless pointer or 'tabstop' changed
    if (prev_line != line || prev_ts != wp->w_buffer->b_p_ts
	    || prev_tick != CHANGEDTICK(wp->w_buffer)
# ifdef FEAT_VARTABS
	    || prev_vts != wp->w_buffer->b_p_vts_array
# endif
	)
    {
	prev_line = line;
	prev_ts = wp->w_buffer->b_p_ts;
	prev_tick = CHANGEDTICK(wp->w_buffer);
# ifdef FEAT_VARTABS
	prev_vts = wp->w_buffer->b_p_vts_array;
	prev_indent = get_indent_str_vtab(line,
				     (int)wp->w_buffer->b_p_ts,
				    wp->w_buffer->b_p_vts_array, wp->w_p_list);
# else
	prev_indent = get_indent_str(line,
				     (int)wp->w_buffer->b_p_ts, wp->w_p_list);
# endif
    }
    bri = prev_indent + wp->w_p_brishift;

    // indent minus the length of the showbreak string
    if (wp->w_p_brisbr)
	bri -= vim_strsize(p_sbr);

    // Add offset for number column, if 'n' is in 'cpoptions'
    bri += win_col_off2(wp);

    // never indent past left window margin
    if (bri < 0)
	bri = 0;
    // always leave at least bri_min characters on the left,
    // if text width is sufficient
    else if (bri > eff_wwidth - wp->w_p_brimin)
	bri = (eff_wwidth - wp->w_p_brimin < 0)
			    ? 0 : eff_wwidth - wp->w_p_brimin;

    return bri;
}
#endif

/*
 * When extra == 0: Return TRUE if the cursor is before or on the first
 *		    non-blank in the line.
 * When extra == 1: Return TRUE if the cursor is before the first non-blank in
 *		    the line.
 */
    int
inindent(int extra)
{
    char_u	*ptr;
    colnr_T	col;

    for (col = 0, ptr = ml_get_curline(); VIM_ISWHITE(*ptr); ++col)
	++ptr;
    if (col >= curwin->w_cursor.col + extra)
	return TRUE;
    else
	return FALSE;
}

#if defined(FEAT_LISP) || defined(FEAT_CINDENT) || defined(PROTO)
/*
 * op_reindent - handle reindenting a block of lines.
 */
    void
op_reindent(oparg_T *oap, int (*how)(void))
{
    long	i;
    char_u	*l;
    int		amount;
    linenr_T	first_changed = 0;
    linenr_T	last_changed = 0;
    linenr_T	start_lnum = curwin->w_cursor.lnum;

    // Don't even try when 'modifiable' is off.
    if (!curbuf->b_p_ma)
    {
	emsg(_(e_modifiable));
	return;
    }

    for (i = oap->line_count; --i >= 0 && !got_int; )
    {
	// it's a slow thing to do, so give feedback so there's no worry that
	// the computer's just hung.

	if (i > 1
		&& (i % 50 == 0 || i == oap->line_count - 1)
		&& oap->line_count > p_report)
	    smsg(_("%ld lines to indent... "), i);

	// Be vi-compatible: For lisp indenting the first line is not
	// indented, unless there is only one line.
# ifdef FEAT_LISP
	if (i != oap->line_count - 1 || oap->line_count == 1
						    || how != get_lisp_indent)
# endif
	{
	    l = skipwhite(ml_get_curline());
	    if (*l == NUL)		    // empty or blank line
		amount = 0;
	    else
		amount = how();		    // get the indent for this line

	    if (amount >= 0 && set_indent(amount, SIN_UNDO))
	    {
		// did change the indent, call changed_lines() later
		if (first_changed == 0)
		    first_changed = curwin->w_cursor.lnum;
		last_changed = curwin->w_cursor.lnum;
	    }
	}
	++curwin->w_cursor.lnum;
	curwin->w_cursor.col = 0;  // make sure it's valid
    }

    // put cursor on first non-blank of indented line
    curwin->w_cursor.lnum = start_lnum;
    beginline(BL_SOL | BL_FIX);

    // Mark changed lines so that they will be redrawn.  When Visual
    // highlighting was present, need to continue until the last line.  When
    // there is no change still need to remove the Visual highlighting.
    if (last_changed != 0)
	changed_lines(first_changed, 0,
		oap->is_VIsual ? start_lnum + oap->line_count :
		last_changed + 1, 0L);
    else if (oap->is_VIsual)
	redraw_curbuf_later(INVERTED);

    if (oap->line_count > p_report)
    {
	i = oap->line_count - (i + 1);
	smsg(NGETTEXT("%ld line indented ",
						 "%ld lines indented ", i), i);
    }
    // set '[ and '] marks
    curbuf->b_op_start = oap->start;
    curbuf->b_op_end = oap->end;
}
#endif // defined(FEAT_LISP) || defined(FEAT_CINDENT)

#if defined(FEAT_SMARTINDENT) || defined(FEAT_CINDENT) || defined(PROTO)
/*
 * Return TRUE if lines starting with '#' should be left aligned.
 */
    int
preprocs_left(void)
{
    return
# ifdef FEAT_SMARTINDENT
#  ifdef FEAT_CINDENT
	(curbuf->b_p_si && !curbuf->b_p_cin) ||
#  else
	curbuf->b_p_si
#  endif
# endif
# ifdef FEAT_CINDENT
	(curbuf->b_p_cin && in_cinkeys('#', ' ', TRUE)
					   && curbuf->b_ind_hash_comment == 0)
# endif
	;
}
#endif

#ifdef FEAT_SMARTINDENT
/*
 * Try to do some very smart auto-indenting.
 * Used when inserting a "normal" character.
 */
    void
ins_try_si(int c)
{
    pos_T	*pos, old_pos;
    char_u	*ptr;
    int		i;
    int		temp;

    // do some very smart indenting when entering '{' or '}'
    if (((did_si || can_si_back) && c == '{') || (can_si && c == '}'))
    {
	// for '}' set indent equal to indent of line containing matching '{'
	if (c == '}' && (pos = findmatch(NULL, '{')) != NULL)
	{
	    old_pos = curwin->w_cursor;
	    // If the matching '{' has a ')' immediately before it (ignoring
	    // white-space), then line up with the start of the line
	    // containing the matching '(' if there is one.  This handles the
	    // case where an "if (..\n..) {" statement continues over multiple
	    // lines -- webb
	    ptr = ml_get(pos->lnum);
	    i = pos->col;
	    if (i > 0)		// skip blanks before '{'
		while (--i > 0 && VIM_ISWHITE(ptr[i]))
		    ;
	    curwin->w_cursor.lnum = pos->lnum;
	    curwin->w_cursor.col = i;
	    if (ptr[i] == ')' && (pos = findmatch(NULL, '(')) != NULL)
		curwin->w_cursor = *pos;
	    i = get_indent();
	    curwin->w_cursor = old_pos;
	    if (State & VREPLACE_FLAG)
		change_indent(INDENT_SET, i, FALSE, NUL, TRUE);
	    else
		(void)set_indent(i, SIN_CHANGED);
	}
	else if (curwin->w_cursor.col > 0)
	{
	    // when inserting '{' after "O" reduce indent, but not
	    // more than indent of previous line
	    temp = TRUE;
	    if (c == '{' && can_si_back && curwin->w_cursor.lnum > 1)
	    {
		old_pos = curwin->w_cursor;
		i = get_indent();
		while (curwin->w_cursor.lnum > 1)
		{
		    ptr = skipwhite(ml_get(--(curwin->w_cursor.lnum)));

		    // ignore empty lines and lines starting with '#'.
		    if (*ptr != '#' && *ptr != NUL)
			break;
		}
		if (get_indent() >= i)
		    temp = FALSE;
		curwin->w_cursor = old_pos;
	    }
	    if (temp)
		shift_line(TRUE, FALSE, 1, TRUE);
	}
    }

    // set indent of '#' always to 0
    if (curwin->w_cursor.col > 0 && can_si && c == '#')
    {
	// remember current indent for next line
	old_indent = get_indent();
	(void)set_indent(0, SIN_CHANGED);
    }

    // Adjust ai_col, the char at this position can be deleted.
    if (ai_col > curwin->w_cursor.col)
	ai_col = curwin->w_cursor.col;
}
#endif

/*
 * Insert an indent (for <Tab> or CTRL-T) or delete an indent (for CTRL-D).
 * Keep the cursor on the same character.
 * type == INDENT_INC	increase indent (for CTRL-T or <Tab>)
 * type == INDENT_DEC	decrease indent (for CTRL-D)
 * type == INDENT_SET	set indent to "amount"
 * if round is TRUE, round the indent to 'shiftwidth' (only with _INC and _Dec).
 */
    void
change_indent(
    int		type,
    int		amount,
    int		round,
    int		replaced,	// replaced character, put on replace stack
    int		call_changed_bytes)	// call changed_bytes()
{
    int		vcol;
    int		last_vcol;
    int		insstart_less;		// reduction for Insstart.col
    int		new_cursor_col;
    int		i;
    char_u	*ptr;
    int		save_p_list;
    int		start_col;
    colnr_T	vc;
    colnr_T	orig_col = 0;		// init for GCC
    char_u	*new_line, *orig_line = NULL;	// init for GCC

    // VREPLACE mode needs to know what the line was like before changing
    if (State & VREPLACE_FLAG)
    {
	orig_line = vim_strsave(ml_get_curline());  // Deal with NULL below
	orig_col = curwin->w_cursor.col;
    }

    // for the following tricks we don't want list mode
    save_p_list = curwin->w_p_list;
    curwin->w_p_list = FALSE;
    vc = getvcol_nolist(&curwin->w_cursor);
    vcol = vc;

    // For Replace mode we need to fix the replace stack later, which is only
    // possible when the cursor is in the indent.  Remember the number of
    // characters before the cursor if it's possible.
    start_col = curwin->w_cursor.col;

    // determine offset from first non-blank
    new_cursor_col = curwin->w_cursor.col;
    beginline(BL_WHITE);
    new_cursor_col -= curwin->w_cursor.col;

    insstart_less = curwin->w_cursor.col;

    // If the cursor is in the indent, compute how many screen columns the
    // cursor is to the left of the first non-blank.
    if (new_cursor_col < 0)
	vcol = get_indent() - vcol;

    if (new_cursor_col > 0)	    // can't fix replace stack
	start_col = -1;

    // Set the new indent.  The cursor will be put on the first non-blank.
    if (type == INDENT_SET)
	(void)set_indent(amount, call_changed_bytes ? SIN_CHANGED : 0);
    else
    {
	int	save_State = State;

	// Avoid being called recursively.
	if (State & VREPLACE_FLAG)
	    State = INSERT;
	shift_line(type == INDENT_DEC, round, 1, call_changed_bytes);
	State = save_State;
    }
    insstart_less -= curwin->w_cursor.col;

    // Try to put cursor on same character.
    // If the cursor is at or after the first non-blank in the line,
    // compute the cursor column relative to the column of the first
    // non-blank character.
    // If we are not in insert mode, leave the cursor on the first non-blank.
    // If the cursor is before the first non-blank, position it relative
    // to the first non-blank, counted in screen columns.
    if (new_cursor_col >= 0)
    {
	// When changing the indent while the cursor is touching it, reset
	// Insstart_col to 0.
	if (new_cursor_col == 0)
	    insstart_less = MAXCOL;
	new_cursor_col += curwin->w_cursor.col;
    }
    else if (!(State & INSERT))
	new_cursor_col = curwin->w_cursor.col;
    else
    {
	// Compute the screen column where the cursor should be.
	vcol = get_indent() - vcol;
	curwin->w_virtcol = (colnr_T)((vcol < 0) ? 0 : vcol);

	// Advance the cursor until we reach the right screen column.
	vcol = last_vcol = 0;
	new_cursor_col = -1;
	ptr = ml_get_curline();
	while (vcol <= (int)curwin->w_virtcol)
	{
	    last_vcol = vcol;
	    if (has_mbyte && new_cursor_col >= 0)
		new_cursor_col += (*mb_ptr2len)(ptr + new_cursor_col);
	    else
		++new_cursor_col;
	    vcol += lbr_chartabsize(ptr, ptr + new_cursor_col, (colnr_T)vcol);
	}
	vcol = last_vcol;

	// May need to insert spaces to be able to position the cursor on
	// the right screen column.
	if (vcol != (int)curwin->w_virtcol)
	{
	    curwin->w_cursor.col = (colnr_T)new_cursor_col;
	    i = (int)curwin->w_virtcol - vcol;
	    ptr = alloc(i + 1);
	    if (ptr != NULL)
	    {
		new_cursor_col += i;
		ptr[i] = NUL;
		while (--i >= 0)
		    ptr[i] = ' ';
		ins_str(ptr);
		vim_free(ptr);
	    }
	}

	// When changing the indent while the cursor is in it, reset
	// Insstart_col to 0.
	insstart_less = MAXCOL;
    }

    curwin->w_p_list = save_p_list;

    if (new_cursor_col <= 0)
	curwin->w_cursor.col = 0;
    else
	curwin->w_cursor.col = (colnr_T)new_cursor_col;
    curwin->w_set_curswant = TRUE;
    changed_cline_bef_curs();

    // May have to adjust the start of the insert.
    if (State & INSERT)
    {
	if (curwin->w_cursor.lnum == Insstart.lnum && Insstart.col != 0)
	{
	    if ((int)Insstart.col <= insstart_less)
		Insstart.col = 0;
	    else
		Insstart.col -= insstart_less;
	}
	if ((int)ai_col <= insstart_less)
	    ai_col = 0;
	else
	    ai_col -= insstart_less;
    }

    // For REPLACE mode, may have to fix the replace stack, if it's possible.
    // If the number of characters before the cursor decreased, need to pop a
    // few characters from the replace stack.
    // If the number of characters before the cursor increased, need to push a
    // few NULs onto the replace stack.
    if (REPLACE_NORMAL(State) && start_col >= 0)
    {
	while (start_col > (int)curwin->w_cursor.col)
	{
	    replace_join(0);	    // remove a NUL from the replace stack
	    --start_col;
	}
	while (start_col < (int)curwin->w_cursor.col || replaced)
	{
	    replace_push(NUL);
	    if (replaced)
	    {
		replace_push(replaced);
		replaced = NUL;
	    }
	    ++start_col;
	}
    }

    // For VREPLACE mode, we also have to fix the replace stack.  In this case
    // it is always possible because we backspace over the whole line and then
    // put it back again the way we wanted it.
    if (State & VREPLACE_FLAG)
    {
	// If orig_line didn't allocate, just return.  At least we did the job,
	// even if you can't backspace.
	if (orig_line == NULL)
	    return;

	// Save new line
	new_line = vim_strsave(ml_get_curline());
	if (new_line == NULL)
	    return;

	// We only put back the new line up to the cursor
	new_line[curwin->w_cursor.col] = NUL;

	// Put back original line
	ml_replace(curwin->w_cursor.lnum, orig_line, FALSE);
	curwin->w_cursor.col = orig_col;

	// Backspace from cursor to start of line
	backspace_until_column(0);

	// Insert new stuff into line again
	ins_bytes(new_line);

	vim_free(new_line);
    }
}

/*
 * Copy the indent from ptr to the current line (and fill to size)
 * Leaves the cursor on the first non-blank in the line.
 * Returns TRUE if the line was changed.
 */
    int
copy_indent(int size, char_u *src)
{
    char_u	*p = NULL;
    char_u	*line = NULL;
    char_u	*s;
    int		todo;
    int		ind_len;
    int		line_len = 0;
    int		tab_pad;
    int		ind_done;
    int		round;
#ifdef FEAT_VARTABS
    int		ind_col;
#endif

    // Round 1: compute the number of characters needed for the indent
    // Round 2: copy the characters.
    for (round = 1; round <= 2; ++round)
    {
	todo = size;
	ind_len = 0;
	ind_done = 0;
#ifdef FEAT_VARTABS
	ind_col = 0;
#endif
	s = src;

	// Count/copy the usable portion of the source line
	while (todo > 0 && VIM_ISWHITE(*s))
	{
	    if (*s == TAB)
	    {
#ifdef FEAT_VARTABS
		tab_pad = tabstop_padding(ind_done, curbuf->b_p_ts,
							curbuf->b_p_vts_array);
#else
		tab_pad = (int)curbuf->b_p_ts
					   - (ind_done % (int)curbuf->b_p_ts);
#endif
		// Stop if this tab will overshoot the target
		if (todo < tab_pad)
		    break;
		todo -= tab_pad;
		ind_done += tab_pad;
#ifdef FEAT_VARTABS
		ind_col += tab_pad;
#endif
	    }
	    else
	    {
		--todo;
		++ind_done;
#ifdef FEAT_VARTABS
		++ind_col;
#endif
	    }
	    ++ind_len;
	    if (p != NULL)
		*p++ = *s;
	    ++s;
	}

	// Fill to next tabstop with a tab, if possible
#ifdef FEAT_VARTABS
	tab_pad = tabstop_padding(ind_done, curbuf->b_p_ts,
							curbuf->b_p_vts_array);
#else
	tab_pad = (int)curbuf->b_p_ts - (ind_done % (int)curbuf->b_p_ts);
#endif
	if (todo >= tab_pad && !curbuf->b_p_et)
	{
	    todo -= tab_pad;
	    ++ind_len;
#ifdef FEAT_VARTABS
	    ind_col += tab_pad;
#endif
	    if (p != NULL)
		*p++ = TAB;
	}

	// Add tabs required for indent
	if (!curbuf->b_p_et)
	{
#ifdef FEAT_VARTABS
	    for (;;)
	    {
		tab_pad = tabstop_padding(ind_col, curbuf->b_p_ts,
							curbuf->b_p_vts_array);
		if (todo < tab_pad)
		    break;
		todo -= tab_pad;
		++ind_len;
		ind_col += tab_pad;
		if (p != NULL)
		    *p++ = TAB;
	    }
#else
	    while (todo >= (int)curbuf->b_p_ts)
	    {
		todo -= (int)curbuf->b_p_ts;
		++ind_len;
		if (p != NULL)
		    *p++ = TAB;
	    }
#endif
	}

	// Count/add spaces required for indent
	while (todo > 0)
	{
	    --todo;
	    ++ind_len;
	    if (p != NULL)
		*p++ = ' ';
	}

	if (p == NULL)
	{
	    // Allocate memory for the result: the copied indent, new indent
	    // and the rest of the line.
	    line_len = (int)STRLEN(ml_get_curline()) + 1;
	    line = alloc(ind_len + line_len);
	    if (line == NULL)
		return FALSE;
	    p = line;
	}
    }

    // Append the original line
    mch_memmove(p, ml_get_curline(), (size_t)line_len);

    // Replace the line
    ml_replace(curwin->w_cursor.lnum, line, FALSE);

    // Put the cursor after the indent.
    curwin->w_cursor.col = ind_len;
    return TRUE;
}

/*
 * ":retab".
 */
    void
ex_retab(exarg_T *eap)
{
    linenr_T	lnum;
    int		got_tab = FALSE;
    long	num_spaces = 0;
    long	num_tabs;
    long	len;
    long	col;
    long	vcol;
    long	start_col = 0;		/* For start of white-space string */
    long	start_vcol = 0;		/* For start of white-space string */
    long	old_len;
    char_u	*ptr;
    char_u	*new_line = (char_u *)1;    /* init to non-NULL */
    int		did_undo;		/* called u_save for current line */
#ifdef FEAT_VARTABS
    int		*new_vts_array = NULL;
    char_u	*new_ts_str;		/* string value of tab argument */
#else
    int		temp;
    int		new_ts;
#endif
    int		save_list;
    linenr_T	first_line = 0;		/* first changed line */
    linenr_T	last_line = 0;		/* last changed line */

    save_list = curwin->w_p_list;
    curwin->w_p_list = 0;	    /* don't want list mode here */

#ifdef FEAT_VARTABS
    new_ts_str = eap->arg;
    if (!tabstop_set(eap->arg, &new_vts_array))
	return;
    while (vim_isdigit(*(eap->arg)) || *(eap->arg) == ',')
	++(eap->arg);

    // This ensures that either new_vts_array and new_ts_str are freshly
    // allocated, or new_vts_array points to an existing array and new_ts_str
    // is null.
    if (new_vts_array == NULL)
    {
	new_vts_array = curbuf->b_p_vts_array;
	new_ts_str = NULL;
    }
    else
	new_ts_str = vim_strnsave(new_ts_str, eap->arg - new_ts_str);
#else
    new_ts = getdigits(&(eap->arg));
    if (new_ts < 0)
    {
	emsg(_(e_positive));
	return;
    }
    if (new_ts == 0)
	new_ts = curbuf->b_p_ts;
#endif
    for (lnum = eap->line1; !got_int && lnum <= eap->line2; ++lnum)
    {
	ptr = ml_get(lnum);
	col = 0;
	vcol = 0;
	did_undo = FALSE;
	for (;;)
	{
	    if (VIM_ISWHITE(ptr[col]))
	    {
		if (!got_tab && num_spaces == 0)
		{
		    /* First consecutive white-space */
		    start_vcol = vcol;
		    start_col = col;
		}
		if (ptr[col] == ' ')
		    num_spaces++;
		else
		    got_tab = TRUE;
	    }
	    else
	    {
		if (got_tab || (eap->forceit && num_spaces > 1))
		{
		    /* Retabulate this string of white-space */

		    /* len is virtual length of white string */
		    len = num_spaces = vcol - start_vcol;
		    num_tabs = 0;
		    if (!curbuf->b_p_et)
		    {
#ifdef FEAT_VARTABS
			int t, s;

			tabstop_fromto(start_vcol, vcol,
					curbuf->b_p_ts, new_vts_array, &t, &s);
			num_tabs = t;
			num_spaces = s;
#else
			temp = new_ts - (start_vcol % new_ts);
			if (num_spaces >= temp)
			{
			    num_spaces -= temp;
			    num_tabs++;
			}
			num_tabs += num_spaces / new_ts;
			num_spaces -= (num_spaces / new_ts) * new_ts;
#endif
		    }
		    if (curbuf->b_p_et || got_tab ||
					(num_spaces + num_tabs < len))
		    {
			if (did_undo == FALSE)
			{
			    did_undo = TRUE;
			    if (u_save((linenr_T)(lnum - 1),
						(linenr_T)(lnum + 1)) == FAIL)
			    {
				new_line = NULL;	/* flag out-of-memory */
				break;
			    }
			}

			/* len is actual number of white characters used */
			len = num_spaces + num_tabs;
			old_len = (long)STRLEN(ptr);
			new_line = alloc(old_len - col + start_col + len + 1);
			if (new_line == NULL)
			    break;
			if (start_col > 0)
			    mch_memmove(new_line, ptr, (size_t)start_col);
			mch_memmove(new_line + start_col + len,
				      ptr + col, (size_t)(old_len - col + 1));
			ptr = new_line + start_col;
			for (col = 0; col < len; col++)
			    ptr[col] = (col < num_tabs) ? '\t' : ' ';
			ml_replace(lnum, new_line, FALSE);
			if (first_line == 0)
			    first_line = lnum;
			last_line = lnum;
			ptr = new_line;
			col = start_col + len;
		    }
		}
		got_tab = FALSE;
		num_spaces = 0;
	    }
	    if (ptr[col] == NUL)
		break;
	    vcol += chartabsize(ptr + col, (colnr_T)vcol);
	    if (has_mbyte)
		col += (*mb_ptr2len)(ptr + col);
	    else
		++col;
	}
	if (new_line == NULL)		    /* out of memory */
	    break;
	line_breakcheck();
    }
    if (got_int)
	emsg(_(e_interr));

#ifdef FEAT_VARTABS
    // If a single value was given then it can be considered equal to
    // either the value of 'tabstop' or the value of 'vartabstop'.
    if (tabstop_count(curbuf->b_p_vts_array) == 0
	&& tabstop_count(new_vts_array) == 1
	&& curbuf->b_p_ts == tabstop_first(new_vts_array))
	; /* not changed */
    else if (tabstop_count(curbuf->b_p_vts_array) > 0
        && tabstop_eq(curbuf->b_p_vts_array, new_vts_array))
	; /* not changed */
    else
	redraw_curbuf_later(NOT_VALID);
#else
    if (curbuf->b_p_ts != new_ts)
	redraw_curbuf_later(NOT_VALID);
#endif
    if (first_line != 0)
	changed_lines(first_line, 0, last_line + 1, 0L);

    curwin->w_p_list = save_list;	/* restore 'list' */

#ifdef FEAT_VARTABS
    if (new_ts_str != NULL)		/* set the new tabstop */
    {
	// If 'vartabstop' is in use or if the value given to retab has more
	// than one tabstop then update 'vartabstop'.
	int *old_vts_ary = curbuf->b_p_vts_array;

	if (tabstop_count(old_vts_ary) > 0 || tabstop_count(new_vts_array) > 1)
	{
	    set_string_option_direct((char_u *)"vts", -1, new_ts_str,
							OPT_FREE|OPT_LOCAL, 0);
	    curbuf->b_p_vts_array = new_vts_array;
	    vim_free(old_vts_ary);
	}
	else
	{
	    // 'vartabstop' wasn't in use and a single value was given to
	    // retab then update 'tabstop'.
	    curbuf->b_p_ts = tabstop_first(new_vts_array);
	    vim_free(new_vts_array);
	}
	vim_free(new_ts_str);
    }
#else
    curbuf->b_p_ts = new_ts;
#endif
    coladvance(curwin->w_curswant);

    u_clearline();
}

#if (defined(FEAT_CINDENT) && defined(FEAT_EVAL)) || defined(PROTO)
/*
 * Get indent level from 'indentexpr'.
 */
    int
get_expr_indent(void)
{
    int		indent = -1;
    char_u	*inde_copy;
    pos_T	save_pos;
    colnr_T	save_curswant;
    int		save_set_curswant;
    int		save_State;
    int		use_sandbox = was_set_insecurely((char_u *)"indentexpr",
								   OPT_LOCAL);

    // Save and restore cursor position and curswant, in case it was changed
    // via :normal commands
    save_pos = curwin->w_cursor;
    save_curswant = curwin->w_curswant;
    save_set_curswant = curwin->w_set_curswant;
    set_vim_var_nr(VV_LNUM, curwin->w_cursor.lnum);
    if (use_sandbox)
	++sandbox;
    ++textlock;

    // Need to make a copy, the 'indentexpr' option could be changed while
    // evaluating it.
    inde_copy = vim_strsave(curbuf->b_p_inde);
    if (inde_copy != NULL)
    {
	indent = (int)eval_to_number(inde_copy);
	vim_free(inde_copy);
    }

    if (use_sandbox)
	--sandbox;
    --textlock;

    // Restore the cursor position so that 'indentexpr' doesn't need to.
    // Pretend to be in Insert mode, allow cursor past end of line for "o"
    // command.
    save_State = State;
    State = INSERT;
    curwin->w_cursor = save_pos;
    curwin->w_curswant = save_curswant;
    curwin->w_set_curswant = save_set_curswant;
    check_cursor();
    State = save_State;

    // If there is an error, just keep the current indent.
    if (indent < 0)
	indent = get_indent();

    return indent;
}
#endif

#if defined(FEAT_LISP) || defined(PROTO)

    static int
lisp_match(char_u *p)
{
    char_u	buf[LSIZE];
    int		len;
    char_u	*word = *curbuf->b_p_lw != NUL ? curbuf->b_p_lw : p_lispwords;

    while (*word != NUL)
    {
	(void)copy_option_part(&word, buf, LSIZE, ",");
	len = (int)STRLEN(buf);
	if (STRNCMP(buf, p, len) == 0 && p[len] == ' ')
	    return TRUE;
    }
    return FALSE;
}

/*
 * When 'p' is present in 'cpoptions, a Vi compatible method is used.
 * The incompatible newer method is quite a bit better at indenting
 * code in lisp-like languages than the traditional one; it's still
 * mostly heuristics however -- Dirk van Deun, dirk@rave.org
 *
 * TODO:
 * Findmatch() should be adapted for lisp, also to make showmatch
 * work correctly: now (v5.3) it seems all C/C++ oriented:
 * - it does not recognize the #\( and #\) notations as character literals
 * - it doesn't know about comments starting with a semicolon
 * - it incorrectly interprets '(' as a character literal
 * All this messes up get_lisp_indent in some rare cases.
 * Update from Sergey Khorev:
 * I tried to fix the first two issues.
 */
    int
get_lisp_indent(void)
{
    pos_T	*pos, realpos, paren;
    int		amount;
    char_u	*that;
    colnr_T	col;
    colnr_T	firsttry;
    int		parencount, quotecount;
    int		vi_lisp;

    // Set vi_lisp to use the vi-compatible method
    vi_lisp = (vim_strchr(p_cpo, CPO_LISP) != NULL);

    realpos = curwin->w_cursor;
    curwin->w_cursor.col = 0;

    if ((pos = findmatch(NULL, '(')) == NULL)
	pos = findmatch(NULL, '[');
    else
    {
	paren = *pos;
	pos = findmatch(NULL, '[');
	if (pos == NULL || LT_POSP(pos, &paren))
	    pos = &paren;
    }
    if (pos != NULL)
    {
	// Extra trick: Take the indent of the first previous non-white
	// line that is at the same () level.
	amount = -1;
	parencount = 0;

	while (--curwin->w_cursor.lnum >= pos->lnum)
	{
	    if (linewhite(curwin->w_cursor.lnum))
		continue;
	    for (that = ml_get_curline(); *that != NUL; ++that)
	    {
		if (*that == ';')
		{
		    while (*(that + 1) != NUL)
			++that;
		    continue;
		}
		if (*that == '\\')
		{
		    if (*(that + 1) != NUL)
			++that;
		    continue;
		}
		if (*that == '"' && *(that + 1) != NUL)
		{
		    while (*++that && *that != '"')
		    {
			// skipping escaped characters in the string
			if (*that == '\\')
			{
			    if (*++that == NUL)
				break;
			    if (that[1] == NUL)
			    {
				++that;
				break;
			    }
			}
		    }
		}
		if (*that == '(' || *that == '[')
		    ++parencount;
		else if (*that == ')' || *that == ']')
		    --parencount;
	    }
	    if (parencount == 0)
	    {
		amount = get_indent();
		break;
	    }
	}

	if (amount == -1)
	{
	    curwin->w_cursor.lnum = pos->lnum;
	    curwin->w_cursor.col = pos->col;
	    col = pos->col;

	    that = ml_get_curline();

	    if (vi_lisp && get_indent() == 0)
		amount = 2;
	    else
	    {
		char_u *line = that;

		amount = 0;
		while (*that && col)
		{
		    amount += lbr_chartabsize_adv(line, &that, (colnr_T)amount);
		    col--;
		}

		// Some keywords require "body" indenting rules (the
		// non-standard-lisp ones are Scheme special forms):
		//
		// (let ((a 1))    instead    (let ((a 1))
		//   (...))	      of	   (...))

		if (!vi_lisp && (*that == '(' || *that == '[')
						      && lisp_match(that + 1))
		    amount += 2;
		else
		{
		    that++;
		    amount++;
		    firsttry = amount;

		    while (VIM_ISWHITE(*that))
		    {
			amount += lbr_chartabsize(line, that, (colnr_T)amount);
			++that;
		    }

		    if (*that && *that != ';') // not a comment line
		    {
			// test *that != '(' to accommodate first let/do
			// argument if it is more than one line
			if (!vi_lisp && *that != '(' && *that != '[')
			    firsttry++;

			parencount = 0;
			quotecount = 0;

			if (vi_lisp
				|| (*that != '"'
				    && *that != '\''
				    && *that != '#'
				    && (*that < '0' || *that > '9')))
			{
			    while (*that
				    && (!VIM_ISWHITE(*that)
					|| quotecount
					|| parencount)
				    && (!((*that == '(' || *that == '[')
					    && !quotecount
					    && !parencount
					    && vi_lisp)))
			    {
				if (*that == '"')
				    quotecount = !quotecount;
				if ((*that == '(' || *that == '[')
							       && !quotecount)
				    ++parencount;
				if ((*that == ')' || *that == ']')
							       && !quotecount)
				    --parencount;
				if (*that == '\\' && *(that+1) != NUL)
				    amount += lbr_chartabsize_adv(
						line, &that, (colnr_T)amount);
				amount += lbr_chartabsize_adv(
						line, &that, (colnr_T)amount);
			    }
			}
			while (VIM_ISWHITE(*that))
			{
			    amount += lbr_chartabsize(
						 line, that, (colnr_T)amount);
			    that++;
			}
			if (!*that || *that == ';')
			    amount = firsttry;
		    }
		}
	    }
	}
    }
    else
	amount = 0;	// no matching '(' or '[' found, use zero indent

    curwin->w_cursor = realpos;

    return amount;
}
#endif // FEAT_LISP

#if defined(FEAT_LISP) || defined(FEAT_CINDENT) || defined(PROTO)
/*
 * Re-indent the current line, based on the current contents of it and the
 * surrounding lines. Fixing the cursor position seems really easy -- I'm very
 * confused what all the part that handles Control-T is doing that I'm not.
 * "get_the_indent" should be get_c_indent, get_expr_indent or get_lisp_indent.
 */

    void
fixthisline(int (*get_the_indent)(void))
{
    int amount = get_the_indent();

    if (amount >= 0)
    {
	change_indent(INDENT_SET, amount, FALSE, 0, TRUE);
	if (linewhite(curwin->w_cursor.lnum))
	    did_ai = TRUE;	// delete the indent if the line stays empty
    }
}

    void
fix_indent(void)
{
    if (p_paste)
	return;
# ifdef FEAT_LISP
    if (curbuf->b_p_lisp && curbuf->b_p_ai)
	fixthisline(get_lisp_indent);
# endif
# if defined(FEAT_LISP) && defined(FEAT_CINDENT)
    else
# endif
# ifdef FEAT_CINDENT
	if (cindent_on())
	    do_c_expr_indent();
# endif
}
#endif

#if defined(FEAT_EVAL) || defined(PROTO)
/*
 * "indent()" function
 */
    void
f_indent(typval_T *argvars, typval_T *rettv)
{
    linenr_T	lnum;

    lnum = tv_get_lnum(argvars);
    if (lnum >= 1 && lnum <= curbuf->b_ml.ml_line_count)
	rettv->vval.v_number = get_indent_lnum(lnum);
    else
	rettv->vval.v_number = -1;
}

/*
 * "lispindent(lnum)" function
 */
    void
f_lispindent(typval_T *argvars UNUSED, typval_T *rettv)
{
#ifdef FEAT_LISP
    pos_T	pos;
    linenr_T	lnum;

    pos = curwin->w_cursor;
    lnum = tv_get_lnum(argvars);
    if (lnum >= 1 && lnum <= curbuf->b_ml.ml_line_count)
    {
	curwin->w_cursor.lnum = lnum;
	rettv->vval.v_number = get_lisp_indent();
	curwin->w_cursor = pos;
    }
    else
#endif
	rettv->vval.v_number = -1;
}
#endif