view src/indent.c @ 35308:22c03485f222 v9.1.0456

patch 9.1.0456: Left shift is incorrect with vartabstop and shiftwidth=0 Commit: https://github.com/vim/vim/commit/88d4f255b7b7a19bb4f6489e0ad0956e47d51fed Author: Gary Johnson <garyjohn@spocom.com> Date: Sat Jun 1 20:51:33 2024 +0200 patch 9.1.0456: Left shift is incorrect with vartabstop and shiftwidth=0 Problem: Left shift is incorrect with vartabstop and shiftwidth=0 Solution: make tabstop_at() function aware of shift direction (Gary Johnson) The problem was that with 'vartabstop' set and 'shiftwidth' equal 0, left shifts using << were shifting the line to the wrong column. The tabstop to the right of the first character in the line was being used as the shift amount instead of the tabstop to the left of that first character. The reason was that the tabstop_at() function always returned the value of the tabstop to the right of the given column and was not accounting for the direction of the shift. The solution was to make tabstop_at() aware of the direction of the shift and to choose the tabtop accordingly. A test was added to check this behavior and make sure it doesn't regress. While at it, also fix a few indentation/alignment issues. fixes: #14864 closes: #14887 Signed-off-by: Gary Johnson <garyjohn@spocom.com> Signed-off-by: Christian Brabandt <cb@256bit.org>
author Christian Brabandt <cb@256bit.org>
date Sat, 01 Jun 2024 21:00:03 +0200
parents bfd2c0032686
children 5c89a485e597
line wrap: on
line source

/* 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.
 * Return FAIL for an error.
 */
    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 OK;
    }

    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_argument_must_be_positive));
		else
		    semsg(_(e_invalid_argument_str), cp);
		return FAIL;
	    }
	}

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

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

    t = 1;
    for (cp = var; *cp != NUL;)
    {
	int n = atoi((char *)cp);

	// Catch negative values, overflow and ridiculous big values.
	if (n <= 0 || n > TABSTOP_MAX)
	{
	    semsg(_(e_invalid_argument_str), cp);
	    VIM_CLEAR(*array);
	    return FAIL;
	}
	(*array)[t++] = n;
	while (*cp != NUL && *cp != ',')
	    ++cp;
	if (*cp != NUL)
	    ++cp;
    }

    return OK;
}

/*
 * 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.
 *
 * If this is being called as part of a shift operation, col is not the cursor
 * column but is the column number to the left of the first non-whitespace
 * character in the line.  If the shift is to the left (left = TRUE), then
 * return the size of the tab interval to the left of the column.
 */
    int
tabstop_at(colnr_T col, int ts, int *vts, int left)
{
    int		tabcount;	// Number of tab stops in the list of variable
				// tab stops.
    colnr_T	tabcol = 0;	// Column of the tab stop under consideration.
    int		t;		// Tabstop index in the list of variable tab
				// stops.
    int		tab_size = 0;	// Size of the tab stop interval to the right
				// or left of the col.

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

    tabcount = vts[0];
    for (t = 1; t <= tabcount; ++t)
    {
	tabcol += vts[t];
	if (tabcol > col)
	{
	    // If shifting left (left != 0), and if the column to the left of
	    // the first first non-blank character (col) in the line is
	    // already to the left of the first tabstop, set the shift amount
	    // (tab_size) to just enough to shift the line to the left margin.
	    // The value doesn't seem to matter as long as it is at least that
	    // distance.
	    if (left && (t == 1))
		tab_size = col;
	    else
		tab_size = vts[t - (left ? 1 : 0)];
	    break;
	}
    }
    if (t > tabcount)		// If the value of the index t is beyond the
				// end of the list, use the tab stop value at
				// the end of the list.
	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 - col % 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 col - (col - excess) % 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, FALSE);
}

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

    curwin->w_cursor = *pos;
    sw_value = get_sw_value_col(buf, get_nolist_virtcol(), left);
    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, int left)
{
    pos_T pos = curwin->w_cursor;

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

/*
 * Idem, using virtual column "col".
 */
    long
get_sw_value_col(buf_T *buf, colnr_T col UNUSED, int left 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, left);
#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)buf->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		no_ts) // if TRUE, count a tab as ^I
{
    int		count = 0;

    for ( ; *ptr; ++ptr)
    {
	if (*ptr == TAB)    // count a tab for what it is worth
	{
	    if (!no_ts)
		count += ts - (count % ts);
	    else
		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 "no_ts" is TRUE, count a tab as ^I.
 */
    int
get_indent_str_vtab(char_u *ptr, int ts, int *vts, int no_ts)
{
    int		count = 0;

    for ( ; *ptr; ++ptr)
    {
	if (*ptr == TAB)    // count a tab for what it is worth
	{
	    if (!no_ts)
		count += tabstop_padding(count, ts, vts);
	    else
		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)
    {
	colnr_T old_offset = (colnr_T)(p - oldline);
	colnr_T new_offset = (colnr_T)(s - newline);

	// this may free "newline"
	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 >= old_offset)
		// cursor was after the indent, adjust for the number of
		// bytes added/removed
		saved_cursor.col += ind_len - old_offset;
	    else if (saved_cursor.col >= new_offset)
		// 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 = new_offset;
	}
#ifdef FEAT_PROP_POPUP
	{
	    int added = ind_len - old_offset;

	    // 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,
				  added > 0 ? old_offset : (colnr_T)ind_len,
				  added, APC_INDENT);
	}
#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 & MODE_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)
/*
 * This is called when 'breakindentopt' is changed and when a window is
 * initialized.
 */
    int
briopt_check(win_T *wp)
{
    char_u	*p;
    int		bri_shift = 0;
    long	bri_min = 20;
    int		bri_sbr = FALSE;
    int		bri_list = 0;
    int		bri_vcol = 0;

    p = wp->w_p_briopt;
    while (*p != NUL)
    {
	// Note: Keep this in sync with p_briopt_values
	if (STRNCMP(p, "shift:", 6) == 0
		 && ((p[6] == '-' && VIM_ISDIGIT(p[7])) || VIM_ISDIGIT(p[6])))
	{
	    p += 6;
	    bri_shift = getdigits(&p);
	}
	else if (STRNCMP(p, "min:", 4) == 0 && VIM_ISDIGIT(p[4]))
	{
	    p += 4;
	    bri_min = getdigits(&p);
	}
	else if (STRNCMP(p, "sbr", 3) == 0)
	{
	    p += 3;
	    bri_sbr = TRUE;
	}
	else if (STRNCMP(p, "list:", 5) == 0)
	{
	    p += 5;
	    bri_list = getdigits(&p);
	}
	else if (STRNCMP(p, "column:", 7) == 0)
	{
	    p += 7;
	    bri_vcol = getdigits(&p);
	}
	if (*p != ',' && *p != NUL)
	    return FAIL;
	if (*p == ',')
	    ++p;
    }

    wp->w_briopt_shift = bri_shift;
    wp->w_briopt_min   = bri_min;
    wp->w_briopt_sbr   = bri_sbr;
    wp->w_briopt_list  = bri_list;
    wp->w_briopt_vcol  = bri_vcol;

    return OK;
}

/*
 * 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
# ifdef FEAT_VARTABS
    static int      *prev_vts = NULL;   // cached vartabs values
# endif
    static int	    prev_fnum   = 0;	// cached buffer number
    static char_u   *prev_line  = NULL;	// cached copy of "line"
    static varnumber_T prev_tick = 0;   // changedtick of cached value
    static int      prev_list = 0;	// cached list indent
    static int      prev_listopt = 0;	// cached w_p_briopt_list value
    static int      prev_no_ts = FALSE;	// cached no_ts value
    static unsigned prev_dy_uhex = 0;	// cached 'display' "uhex" value
    // cached formatlistpat value
    static char_u   *prev_flp = NULL;
    int		    bri = 0;
    // window width minus window margin space, i.e. what rests for text
    const int	    eff_wwidth = wp->w_width
					  - win_col_off(wp) + win_col_off2(wp);

    // In list mode, if 'listchars' "tab" isn't set, a TAB is displayed as ^I.
    int no_ts = wp->w_p_list && wp->w_lcs_chars.tab1 == NUL;

    // Used cached indent, unless
    // - buffer changed, or
    // - 'tabstop' changed, or
    // - 'vartabstop' changed, or
    // - buffer was changed, or
    // - 'breakindentopt' "list" changed, or
    // - 'list' or 'listchars' "tab" changed, or
    // - 'display' "uhex" flag changed, or
    // - 'formatlistpat' changed, or
    // - line changed.
    if (prev_fnum != wp->w_buffer->b_fnum
	    || prev_ts != wp->w_buffer->b_p_ts
# ifdef FEAT_VARTABS
	    || prev_vts != wp->w_buffer->b_p_vts_array
# endif
	    || prev_tick != CHANGEDTICK(wp->w_buffer)
	    || prev_listopt != wp->w_briopt_list
	    || prev_no_ts != no_ts
	    || prev_dy_uhex != (dy_flags & DY_UHEX)
	    || prev_flp == NULL
	    || STRCMP(prev_flp, get_flp_value(wp->w_buffer)) != 0
	    || prev_line == NULL || STRCMP(prev_line, line) != 0
	)
    {
	prev_fnum = wp->w_buffer->b_fnum;
	vim_free(prev_line);
	prev_line = vim_strsave(line);
	prev_ts = wp->w_buffer->b_p_ts;
# ifdef FEAT_VARTABS
	prev_vts = wp->w_buffer->b_p_vts_array;
	if (wp->w_briopt_vcol == 0)
	    prev_indent = get_indent_str_vtab(line,
				     (int)wp->w_buffer->b_p_ts,
				      wp->w_buffer->b_p_vts_array, no_ts);
# else
	if (wp->w_briopt_vcol == 0)
	    prev_indent = get_indent_str(line,
				        (int)wp->w_buffer->b_p_ts, no_ts);
# endif
	prev_tick = CHANGEDTICK(wp->w_buffer);
	prev_listopt = wp->w_briopt_list;
	prev_list = 0;
	prev_no_ts = no_ts;
	prev_dy_uhex = (dy_flags & DY_UHEX);
	vim_free(prev_flp);
	prev_flp = vim_strsave(get_flp_value(wp->w_buffer));
	// add additional indent for numbered lists
	if (wp->w_briopt_list != 0 && wp->w_briopt_vcol == 0)
	{
	    regmatch_T	    regmatch;

	    regmatch.regprog = vim_regcomp(prev_flp,
				   RE_MAGIC + RE_STRING + RE_AUTO + RE_STRICT);

	    if (regmatch.regprog != NULL)
	    {
		regmatch.rm_ic = FALSE;
		if (vim_regexec(&regmatch, line, 0))
		{
		    if (wp->w_briopt_list > 0)
			prev_list = wp->w_briopt_list;
		    else
			prev_indent = (*regmatch.endp - *regmatch.startp);
		}
		vim_regfree(regmatch.regprog);
	    }
	}
    }
    if (wp->w_briopt_vcol != 0)
    {
	// column value has priority
	bri = wp->w_briopt_vcol;
	prev_list = 0;
    }
    else
	bri = prev_indent + wp->w_briopt_shift;

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

    // add additional indent for numbered lists
    if (wp->w_briopt_list > 0)
	bri += prev_list;

    // indent minus the length of the showbreak string
    if (wp->w_briopt_sbr)
	bri -= vim_strsize(get_showbreak_value(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_briopt_min)
	bri = (eff_wwidth - wp->w_briopt_min < 0)
					   ? 0 : eff_wwidth - wp->w_briopt_min;

    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;
}

/*
 * op_reindent - handle reindenting a block of lines.
 */
    void
op_reindent(oparg_T *oap, int (*how)(void))
{
    long	i = 0;
    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_cannot_make_changes_modifiable_is_off));
	return;
    }

    // Save for undo.  Do this once for all lines, much faster than doing this
    // for each line separately, especially when undoing.
    if (u_savecommon(start_lnum - 1, start_lnum + oap->line_count,
				     start_lnum + oap->line_count, FALSE) == OK)
	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.
	    if (i != oap->line_count - 1 || oap->line_count == 1
						     || how != get_lisp_indent)
	    {
		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, 0))
		{
		    // 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(UPD_INVERTED);

    if (oap->line_count > p_report)
    {
	i = oap->line_count - (i + 1);
	smsg(NGETTEXT("%ld line indented ",
						 "%ld lines indented ", i), i);
    }
    if ((cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0)
    {
	// set '[ and '] marks
	curbuf->b_op_start = oap->start;
	curbuf->b_op_end = oap->end;
    }
}

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

/*
 * Return TRUE if the conditions are OK for smart indenting.
 */
    int
may_do_si(void)
{
    return curbuf->b_p_si
	&& !curbuf->b_p_cin
# ifdef FEAT_EVAL
	&& *curbuf->b_p_inde == NUL
# endif
	&& !p_paste;
}

/*
 * 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 == '}' && inindent(0)))
    {
	// 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 == '#' && inindent(0))
    {
	// 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;
}

/*
 * 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

    // MODE_VREPLACE state 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;
#ifdef FEAT_PROP_POPUP
    ignore_text_props = TRUE;
#endif
    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 = MODE_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 & MODE_INSERT))
	new_cursor_col = curwin->w_cursor.col;
    else
    {
	chartabsize_T cts;

	// 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.
	last_vcol = 0;
	ptr = ml_get_curline();
	init_chartabsize_arg(&cts, curwin, 0, 0, ptr, ptr);
	while (cts.cts_vcol <= (int)curwin->w_virtcol)
	{
	    last_vcol = cts.cts_vcol;
	    if (cts.cts_vcol > 0)
		MB_PTR_ADV(cts.cts_ptr);
	    if (*cts.cts_ptr == NUL)
		break;
	    cts.cts_vcol += lbr_chartabsize(&cts);
	}
	vcol = last_vcol;
	new_cursor_col = cts.cts_ptr - cts.cts_line;
	clear_chartabsize_arg(&cts);

	// 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 & MODE_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 MODE_REPLACE state, 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;
	}
    }
#ifdef FEAT_PROP_POPUP
    ignore_text_props = FALSE;
#endif

    // For MODE_VREPLACE state, 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 = ml_get_curline_len() + 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;
}

/*
 * Give a "resulting text too long" error and maybe set got_int.
 */
    static void
emsg_text_too_long(void)
{
    emsg(_(e_resulting_text_too_long));
#ifdef FEAT_EVAL
    // when not inside a try/catch set got_int to break out of any loop
    if (trylevel == 0)
#endif
	got_int = 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;
    long	new_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) == FAIL)
	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
    ptr = eap->arg;
    new_ts = getdigits(&ptr);
    if (new_ts < 0 && *eap->arg == '-')
    {
	emsg(_(e_argument_must_be_positive));
	return;
    }
    if (new_ts < 0 || new_ts > TABSTOP_MAX)
    {
	semsg(_(e_invalid_argument_str), eap->arg);
	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_len = old_len - col + start_col + len + 1;
			if (new_len <= 0 || new_len >= MAXCOL)
			{
			    emsg_text_too_long();
			    break;
			}
			new_line = alloc(new_len);
			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' : ' ';
			if (ml_replace(lnum, new_line, FALSE) == OK)
			    // "new_line" may have been copied
			    new_line = curbuf->b_ml.ml_line_ptr;
			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 (vcol >= MAXCOL)
	    {
		emsg_text_too_long();
		break;
	    }
	    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_interrupted));

#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(UPD_NOT_VALID);
#else
    if (curbuf->b_p_ts != new_ts)
	redraw_curbuf_later(UPD_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_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);
    sctx_T	save_sctx = current_sctx;

    // 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;
    current_sctx = curbuf->b_p_script_ctx[BV_INDE];

    // 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, TRUE);
	vim_free(inde_copy);
    }

    if (use_sandbox)
	--sandbox;
    --textlock;
    current_sctx = save_sctx;

    // 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 = MODE_INSERT;
    curwin->w_cursor = save_pos;
    curwin->w_curswant = save_curswant;
    curwin->w_set_curswant = save_set_curswant;
    check_cursor();
    State = save_State;

    // Reset did_throw, unless 'debug' has "throw" and inside a try/catch.
    if (did_throw && (vim_strchr(p_debug, 't') == NULL || trylevel == 0))
    {
	handle_did_throw();
	did_throw = FALSE;
    }

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

    return indent;
}
#endif

    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 && IS_WHITE_OR_NUL(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 == NUL)
			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;
		chartabsize_T	cts;

		init_chartabsize_arg(&cts, curwin, pos->lnum, 0, line, line);
		while (*cts.cts_ptr != NUL && col > 0)
		{
		    cts.cts_vcol += lbr_chartabsize_adv(&cts);
		    col--;
		}
		amount = cts.cts_vcol;
		that = cts.cts_ptr;
		clear_chartabsize_arg(&cts);

		// 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
		{
		    if (*that != NUL)
		    {
			that++;
			amount++;
		    }
		    firsttry = amount;

		    init_chartabsize_arg(&cts, curwin, (colnr_T)(that - line),
							   amount, line, that);
		    while (VIM_ISWHITE(*cts.cts_ptr))
		    {
			cts.cts_vcol += lbr_chartabsize(&cts);
			++cts.cts_ptr;
		    }
		    that = cts.cts_ptr;
		    amount = cts.cts_vcol;
		    clear_chartabsize_arg(&cts);

		    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;

			init_chartabsize_arg(&cts, curwin,
				   (colnr_T)(that - line), amount, line, that);
			if (vi_lisp
				|| (*that != '"'
				    && *that != '\''
				    && *that != '#'
				    && (*that < '0' || *that > '9')))
			{
			    while (*cts.cts_ptr
				    && (!VIM_ISWHITE(*cts.cts_ptr)
					|| quotecount
					|| parencount)
				    && (!((*cts.cts_ptr == '('
							|| *cts.cts_ptr == '[')
					    && !quotecount
					    && !parencount
					    && vi_lisp)))
			    {
				if (*cts.cts_ptr == '"')
				    quotecount = !quotecount;
				if ((*cts.cts_ptr == '(' || *cts.cts_ptr == '[')
							       && !quotecount)
				    ++parencount;
				if ((*cts.cts_ptr == ')' || *cts.cts_ptr == ']')
							       && !quotecount)
				    --parencount;
				if (*cts.cts_ptr == '\\'
						    && *(cts.cts_ptr+1) != NUL)
				    cts.cts_vcol += lbr_chartabsize_adv(&cts);
				cts.cts_vcol += lbr_chartabsize_adv(&cts);
			    }
			}
			while (VIM_ISWHITE(*cts.cts_ptr))
			{
			    cts.cts_vcol += lbr_chartabsize(&cts);
			    ++cts.cts_ptr;
			}
			that = cts.cts_ptr;
			amount = cts.cts_vcol;
			clear_chartabsize_arg(&cts);

			if (!*that || *that == ';')
			    amount = firsttry;
		    }
		}
	    }
	}
    }
    else
	amount = 0;	// no matching '(' or '[' found, use zero indent

    curwin->w_cursor = realpos;

    return amount;
}

/*
 * 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)
	return;

    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
}

/*
 * Return TRUE if 'indentexpr' should be used for Lisp indenting.
 * Caller may want to check 'autoindent'.
 */
    int
use_indentexpr_for_lisp(void)
{
#ifdef FEAT_EVAL
    return curbuf->b_p_lisp
		&& *curbuf->b_p_inde != NUL
		&& STRCMP(curbuf->b_p_lop, "expr:1") == 0;
#else
    return FALSE;
#endif
}

/*
 * Fix indent for 'lisp' and 'cindent'.
 */
    void
fix_indent(void)
{
    if (p_paste)
	return;  // no auto-indenting when 'paste' is set
    if (curbuf->b_p_lisp && curbuf->b_p_ai)
    {
	if (use_indentexpr_for_lisp())
	    do_c_expr_indent();
	else
	    fixthisline(get_lisp_indent);
    }
    else if (cindent_on())
	do_c_expr_indent();
}

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

    if (in_vim9script() && check_for_lnum_arg(argvars, 0) == FAIL)
	return;

    lnum = tv_get_lnum(argvars);
    if (lnum >= 1 && lnum <= curbuf->b_ml.ml_line_count)
	rettv->vval.v_number = get_indent_lnum(lnum);
    else
    {
	if (in_vim9script())
	    semsg(_(e_invalid_line_number_nr), lnum);
	rettv->vval.v_number = -1;
    }
}

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

    if (in_vim9script() && check_for_lnum_arg(argvars, 0) == FAIL)
	return;

    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 if (in_vim9script())
	semsg(_(e_invalid_line_number_nr), lnum);
    else
	rettv->vval.v_number = -1;
}
#endif