NOISSUE change uvim folder name to mnv

Signed-off-by: Mehmet Samet Duman <yongdohyun@projecttick.org>

1 files changed, 0 insertions, 5167 deletions

diff --git a/uvim/src/diff.c b/uvim/src/diff.c
deleted file mode 100644
index fac2da64df..0000000000
--- a/uvim/src/diff.c
+++ /dev/null
@@ -1,5167 +0,0 @@
-/* vi:set ts=8 sts=4 sw=4 noet:
- *
- * MNV - MNV is not Vim	by Bram Moolenaar
- *
- * Do ":help uganda"  in MNV to read copying and usage conditions.
- * Do ":help credits" in MNV to see a list of people who contributed.
- * See README.txt for an overview of the MNV source code.
- */
-
-/*
- * diff.c: code for diff'ing two, three or four buffers.
- *
- * There are three ways to diff:
- * - Shell out to an external diff program, using files.
- * - Use the compiled-in xdiff library.
- * - Let 'diffexpr' do the work, using files.
- */
-
-#include "mnv.h"
-#include "xdiff/xdiff.h"
-
-#if defined(FEAT_DIFF)
-
-static int diff_busy = FALSE;	    // using diff structs, don't change them
-static int diff_need_update = FALSE; // ex_diffupdate needs to be called
-
-// flags obtained from the 'diffopt' option
-# define DIFF_FILLER	0x001	// display filler lines
-# define DIFF_IBLANK	0x002	// ignore empty lines
-# define DIFF_ICASE	0x004	// ignore case
-# define DIFF_IWHITE	0x008	// ignore change in white space
-# define DIFF_IWHITEALL	0x010	// ignore all white space changes
-# define DIFF_IWHITEEOL	0x020	// ignore change in white space at EOL
-# define DIFF_HORIZONTAL	0x040	// horizontal splits
-# define DIFF_VERTICAL	0x080	// vertical splits
-# define DIFF_HIDDEN_OFF	0x100	// diffoff when hidden
-# define DIFF_INTERNAL	0x200	// use internal xdiff algorithm
-# define DIFF_CLOSE_OFF	0x400	// diffoff when closing window
-# define DIFF_FOLLOWWRAP	0x800	// follow the wrap option
-# define DIFF_LINEMATCH  0x1000  // match most similar lines within diff
-# define DIFF_INLINE_NONE    0x2000  // no inline highlight
-# define DIFF_INLINE_SIMPLE  0x4000  // inline highlight with simple algorithm
-# define DIFF_INLINE_CHAR    0x8000  // inline highlight with character diff
-# define DIFF_INLINE_WORD    0x10000 // inline highlight with word diff
-# define DIFF_ANCHOR	0x20000	// use 'diffanchors' to anchor the diff
-# define ALL_WHITE_DIFF (DIFF_IWHITE | DIFF_IWHITEALL | DIFF_IWHITEEOL)
-# define ALL_INLINE (DIFF_INLINE_NONE | DIFF_INLINE_SIMPLE | DIFF_INLINE_CHAR | DIFF_INLINE_WORD)
-# define ALL_INLINE_DIFF (DIFF_INLINE_CHAR | DIFF_INLINE_WORD)
-static int	diff_flags = DIFF_INTERNAL | DIFF_FILLER | DIFF_CLOSE_OFF | DIFF_INLINE_CHAR;
-
-static long diff_algorithm = XDF_INDENT_HEURISTIC;
-static int diff_word_gap = 5;  // gap threshold for inline:word
-
-# define LBUFLEN 50		// length of line in diff file
-
-// Max file size xdiff is equipped to deal with. The value (1GB - 1MB) comes
-// from Git's implementation.
-# define MAX_XDIFF_SIZE (1024L * 1024 * 1023)
-
-static int diff_a_works = MAYBE; // TRUE when "diff -a" works, FALSE when it
-				 // doesn't work, MAYBE when not checked yet
-# if defined(MSWIN)
-static int diff_bin_works = MAYBE; // TRUE when "diff --binary" works, FALSE
-				   // when it doesn't work, MAYBE when not
-				   // checked yet
-# endif
-
-# define MAX_DIFF_ANCHORS 20
-
-// used for diff input
-typedef struct {
-    char_u	*din_fname;  // used for external diff
-    mmfile_t	din_mmfile;  // used for internal diff
-} diffin_T;
-
-// used for diff result
-typedef struct {
-    char_u	*dout_fname;  // used for external diff
-    garray_T	dout_ga;      // used for internal diff
-} diffout_T;
-
-// used for recording hunks from xdiff
-typedef struct {
-    linenr_T lnum_orig;
-    long     count_orig;
-    linenr_T lnum_new;
-    long     count_new;
-} diffhunk_T;
-
-typedef enum {
-    DIO_OUTPUT_INDICES = 0,	// default
-    DIO_OUTPUT_UNIFIED = 1	// unified diff format
-} dio_outfmt_T;
-
-// two diff inputs and one result
-typedef struct {
-    diffin_T	    dio_orig;     // original file input
-    diffin_T	    dio_new;      // new file input
-    diffout_T	    dio_diff;     // diff result
-    int		    dio_internal; // using internal diff
-    dio_outfmt_T    dio_outfmt;   // internal diff output format
-    int		    dio_ctxlen;   // unified diff context length
-} diffio_T;
-
-static int diff_buf_idx(buf_T *buf);
-static int diff_buf_idx_tp(buf_T *buf, tabpage_T *tp);
-static void diff_mark_adjust_tp(tabpage_T *tp, int idx, linenr_T line1, linenr_T line2, long amount, long amount_after);
-static void diff_check_unchanged(tabpage_T *tp, diff_T *dp);
-static int diff_check_sanity(tabpage_T *tp, diff_T *dp);
-static int check_external_diff(diffio_T *diffio);
-static int diff_file(diffio_T *diffio);
-static int diff_equal_entry(diff_T *dp, int idx1, int idx2);
-static int diff_cmp(char_u *s1, char_u *s2);
-# ifdef FEAT_FOLDING
-static void diff_fold_update(diff_T *dp, int skip_idx);
-# endif
-static void diff_read(int idx_orig, int idx_new, diffio_T *dio);
-static void diff_copy_entry(diff_T *dprev, diff_T *dp, int idx_orig, int idx_new);
-static diff_T *diff_alloc_new(tabpage_T *tp, diff_T *dprev, diff_T *dp);
-static int parse_diff_ed(char_u *line, diffhunk_T *hunk);
-static int parse_diff_unified(char_u *line, diffhunk_T *hunk);
-static int xdiff_out_indices(long start_a, long count_a, long start_b, long count_b, void *priv);
-static int xdiff_out_unified(void *priv, mmbuffer_t *mb, int nbuf);
-static int parse_diffanchors(int check_only, buf_T *buf, linenr_T *anchors, int *num_anchors);
-
-# define FOR_ALL_DIFFBLOCKS_IN_TAB(tp, dp) \
-    for ((dp) = (tp)->tp_first_diff; (dp) != NULL; (dp) = (dp)->df_next)
-
-    static void
-clear_diffblock(diff_T *dp)
-{
-    ga_clear(&dp->df_changes);
-    mnv_free(dp);
-}
-
-/*
- * Called when deleting or unloading a buffer: No longer make a diff with it.
- */
-    void
-diff_buf_delete(buf_T *buf)
-{
-    int		i;
-    tabpage_T	*tp;
-
-    FOR_ALL_TABPAGES(tp)
-    {
-	i = diff_buf_idx_tp(buf, tp);
-	if (i != DB_COUNT)
-	{
-	    tp->tp_diffbuf[i] = NULL;
-	    tp->tp_diff_invalid = TRUE;
-	    if (tp == curtab)
-	    {
-		// don't redraw right away, more might change or buffer state
-		// is invalid right now
-		need_diff_redraw = TRUE;
-		redraw_later(UPD_VALID);
-	    }
-	}
-    }
-}
-
-/*
- * Check if the current buffer should be added to or removed from the list of
- * diff buffers.
- */
-    void
-diff_buf_adjust(win_T *win)
-{
-    win_T	*wp;
-    int		i;
-
-    if (!win->w_p_diff)
-    {
-	// When there is no window showing a diff for this buffer, remove
-	// it from the diffs.
-	FOR_ALL_WINDOWS(wp)
-	    if (wp->w_buffer == win->w_buffer && wp->w_p_diff)
-		break;
-	if (wp == NULL)
-	{
-	    i = diff_buf_idx(win->w_buffer);
-	    if (i != DB_COUNT)
-	    {
-		curtab->tp_diffbuf[i] = NULL;
-		curtab->tp_diff_invalid = TRUE;
-		diff_redraw(TRUE);
-	    }
-	}
-    }
-    else
-	diff_buf_add(win->w_buffer);
-}
-
-/*
- * Add a buffer to make diffs for.
- * Call this when a new buffer is being edited in the current window where
- * 'diff' is set.
- * Marks the current buffer as being part of the diff and requiring updating.
- * This must be done before any autocmd, because a command may use info
- * about the screen contents.
- */
-    void
-diff_buf_add(buf_T *buf)
-{
-    int		i;
-
-    if (diff_buf_idx(buf) != DB_COUNT)
-	return;		// It's already there.
-
-    for (i = 0; i < DB_COUNT; ++i)
-	if (curtab->tp_diffbuf[i] == NULL)
-	{
-	    curtab->tp_diffbuf[i] = buf;
-	    curtab->tp_diff_invalid = TRUE;
-	    diff_redraw(TRUE);
-	    return;
-	}
-
-    semsg(_(e_cannot_diff_more_than_nr_buffers), DB_COUNT);
-}
-
-/*
- * Remove all buffers to make diffs for.
- */
-    static void
-diff_buf_clear(void)
-{
-    int		i;
-
-    for (i = 0; i < DB_COUNT; ++i)
-	if (curtab->tp_diffbuf[i] != NULL)
-	{
-	    curtab->tp_diffbuf[i] = NULL;
-	    curtab->tp_diff_invalid = TRUE;
-	    diff_redraw(TRUE);
-	}
-}
-
-/*
- * Find buffer "buf" in the list of diff buffers for the current tab page.
- * Return its index or DB_COUNT if not found.
- */
-    static int
-diff_buf_idx(buf_T *buf)
-{
-    int		idx;
-
-    for (idx = 0; idx < DB_COUNT; ++idx)
-	if (curtab->tp_diffbuf[idx] == buf)
-	    break;
-    return idx;
-}
-
-/*
- * Find buffer "buf" in the list of diff buffers for tab page "tp".
- * Return its index or DB_COUNT if not found.
- */
-    static int
-diff_buf_idx_tp(buf_T *buf, tabpage_T *tp)
-{
-    int		idx;
-
-    for (idx = 0; idx < DB_COUNT; ++idx)
-	if (tp->tp_diffbuf[idx] == buf)
-	    break;
-    return idx;
-}
-
-/*
- * Mark the diff info involving buffer "buf" as invalid, it will be updated
- * when info is requested.
- */
-    void
-diff_invalidate(buf_T *buf)
-{
-    tabpage_T	*tp;
-    int		i;
-
-    FOR_ALL_TABPAGES(tp)
-    {
-	i = diff_buf_idx_tp(buf, tp);
-	if (i != DB_COUNT)
-	{
-	    tp->tp_diff_invalid = TRUE;
-	    if (tp == curtab)
-		diff_redraw(TRUE);
-	}
-    }
-}
-
-/*
- * Called by mark_adjust(): update line numbers in "curbuf".
- */
-    void
-diff_mark_adjust(
-    linenr_T	line1,
-    linenr_T	line2,
-    long	amount,
-    long	amount_after)
-{
-    int		idx;
-    tabpage_T	*tp;
-
-    // Handle all tab pages that use the current buffer in a diff.
-    FOR_ALL_TABPAGES(tp)
-    {
-	idx = diff_buf_idx_tp(curbuf, tp);
-	if (idx != DB_COUNT)
-	    diff_mark_adjust_tp(tp, idx, line1, line2, amount, amount_after);
-    }
-}
-
-/*
- * Update line numbers in tab page "tp" for "curbuf" with index "idx".
- * This attempts to update the changes as much as possible:
- * When inserting/deleting lines outside of existing change blocks, create a
- * new change block and update the line numbers in following blocks.
- * When inserting/deleting lines in existing change blocks, update them.
- */
-    static void
-diff_mark_adjust_tp(
-    tabpage_T	*tp,
-    int		idx,
-    linenr_T	line1,
-    linenr_T	line2,
-    long	amount,
-    long	amount_after)
-{
-    diff_T	*dp;
-    diff_T	*dprev;
-    diff_T	*dnext;
-    int		i;
-    int		inserted, deleted;
-    int		n, off;
-    linenr_T	last;
-    linenr_T	lnum_deleted = line1;	// lnum of remaining deletion
-    int		check_unchanged;
-
-    if (diff_internal())
-    {
-	// Will update diffs before redrawing.  Set _invalid to update the
-	// diffs themselves, set _update to also update folds properly just
-	// before redrawing.
-	// Do update marks here, it is needed for :%diffput.
-	tp->tp_diff_invalid = TRUE;
-	tp->tp_diff_update = TRUE;
-    }
-
-    if (line2 == MAXLNUM)
-    {
-	// mark_adjust(99, MAXLNUM, 9, 0): insert lines
-	inserted = amount;
-	deleted = 0;
-    }
-    else if (amount_after > 0)
-    {
-	// mark_adjust(99, 98, MAXLNUM, 9): a change that inserts lines
-	inserted = amount_after;
-	deleted = 0;
-    }
-    else
-    {
-	// mark_adjust(98, 99, MAXLNUM, -2): delete lines
-	inserted = 0;
-	deleted = -amount_after;
-    }
-
-    dprev = NULL;
-    dp = tp->tp_first_diff;
-    for (;;)
-    {
-	// If the change is after the previous diff block and before the next
-	// diff block, thus not touching an existing change, create a new diff
-	// block.  Don't do this when ex_diffgetput() is busy.
-	if ((dp == NULL || dp->df_lnum[idx] - 1 > line2
-		    || (line2 == MAXLNUM && dp->df_lnum[idx] > line1))
-		&& (dprev == NULL
-		    || dprev->df_lnum[idx] + dprev->df_count[idx] < line1)
-		&& !diff_busy)
-	{
-	    dnext = diff_alloc_new(tp, dprev, dp);
-	    if (dnext == NULL)
-		return;
-
-	    dnext->df_lnum[idx] = line1;
-	    dnext->df_count[idx] = inserted;
-	    for (i = 0; i < DB_COUNT; ++i)
-		if (tp->tp_diffbuf[i] != NULL && i != idx)
-		{
-		    if (dprev == NULL)
-			dnext->df_lnum[i] = line1;
-		    else
-			dnext->df_lnum[i] = line1
-			    + (dprev->df_lnum[i] + dprev->df_count[i])
-			    - (dprev->df_lnum[idx] + dprev->df_count[idx]);
-		    dnext->df_count[i] = deleted;
-		}
-	}
-
-	// if at end of the list, quit
-	if (dp == NULL)
-	    break;
-
-	/*
-	 * Check for these situations:
-	 *	  1  2	3
-	 *	  1  2	3
-	 * line1     2	3  4  5
-	 *	     2	3  4  5
-	 *	     2	3  4  5
-	 * line2     2	3  4  5
-	 *		3     5  6
-	 *		3     5  6
-	 */
-	// compute last line of this change
-	last = dp->df_lnum[idx] + dp->df_count[idx] - 1;
-
-	// 1. change completely above line1: nothing to do
-	if (last >= line1 - 1)
-	{
-	    if (diff_busy)
-	    {
-		// Currently in the middle of updating diff blocks. All we want
-		// is to adjust the line numbers and nothing else.
-		if (dp->df_lnum[idx] > line2)
-		    dp->df_lnum[idx] += amount_after;
-
-		// Advance to next entry.
-		dprev = dp;
-		dp = dp->df_next;
-		continue;
-	    }
-
-	    // 6. change below line2: only adjust for amount_after; also when
-	    // "deleted" became zero when deleted all lines between two diffs
-	    if (dp->df_lnum[idx] - (deleted + inserted != 0) > line2)
-	    {
-		if (amount_after == 0)
-		    break;	// nothing left to change
-		dp->df_lnum[idx] += amount_after;
-	    }
-	    else
-	    {
-		check_unchanged = FALSE;
-
-		// 2. 3. 4. 5.: inserted/deleted lines touching this diff.
-		if (deleted > 0)
-		{
-		    off = 0;
-		    if (dp->df_lnum[idx] >= line1)
-		    {
-			if (last <= line2)
-			{
-			    // 4. delete all lines of diff
-			    if (dp->df_next != NULL
-				    && dp->df_next->df_lnum[idx] - 1 <= line2)
-			    {
-				// delete continues in next diff, only do
-				// lines until that one
-				n = dp->df_next->df_lnum[idx] - lnum_deleted;
-				deleted -= n;
-				n -= dp->df_count[idx];
-				lnum_deleted = dp->df_next->df_lnum[idx];
-			    }
-			    else
-				n = deleted - dp->df_count[idx];
-			    dp->df_count[idx] = 0;
-			}
-			else
-			{
-			    // 5. delete lines at or just before top of diff
-			    off = dp->df_lnum[idx] - lnum_deleted;
-			    n = off;
-			    dp->df_count[idx] -= line2 - dp->df_lnum[idx] + 1;
-			    check_unchanged = TRUE;
-			}
-			dp->df_lnum[idx] = line1;
-		    }
-		    else
-		    {
-			if (last < line2)
-			{
-			    // 2. delete at end of diff
-			    dp->df_count[idx] -= last - lnum_deleted + 1;
-			    if (dp->df_next != NULL
-				    && dp->df_next->df_lnum[idx] - 1 <= line2)
-			    {
-				// delete continues in next diff, only do
-				// lines until that one
-				n = dp->df_next->df_lnum[idx] - 1 - last;
-				deleted -= dp->df_next->df_lnum[idx]
-							       - lnum_deleted;
-				lnum_deleted = dp->df_next->df_lnum[idx];
-			    }
-			    else
-				n = line2 - last;
-			    check_unchanged = TRUE;
-			}
-			else
-			{
-			    // 3. delete lines inside the diff
-			    n = 0;
-			    dp->df_count[idx] -= deleted;
-			}
-		    }
-
-		    for (i = 0; i < DB_COUNT; ++i)
-			if (tp->tp_diffbuf[i] != NULL && i != idx)
-			{
-			    if (dp->df_lnum[i] > off)
-				dp->df_lnum[i] -= off;
-			    else
-				dp->df_lnum[i] = 1;
-			    dp->df_count[i] += n;
-			}
-		}
-		else
-		{
-		    if (dp->df_lnum[idx] <= line1)
-		    {
-			// inserted lines somewhere in this diff
-			dp->df_count[idx] += inserted;
-			check_unchanged = TRUE;
-		    }
-		    else
-			// inserted lines somewhere above this diff
-			dp->df_lnum[idx] += inserted;
-		}
-
-		if (check_unchanged)
-		    // Check if inserted lines are equal, may reduce the
-		    // size of the diff.  TODO: also check for equal lines
-		    // in the middle and perhaps split the block.
-		    diff_check_unchanged(tp, dp);
-	    }
-	}
-
-	// check if this block touches the previous one, may merge them.
-	if (dprev != NULL && !dp->is_linematched && !diff_busy
-				&& dprev->df_lnum[idx] + dprev->df_count[idx]
-							== dp->df_lnum[idx])
-	{
-	    for (i = 0; i < DB_COUNT; ++i)
-		if (tp->tp_diffbuf[i] != NULL)
-		    dprev->df_count[i] += dp->df_count[i];
-	    dprev->df_next = dp->df_next;
-	    clear_diffblock(dp);
-	    dp = dprev->df_next;
-	}
-	else
-	{
-	    // Advance to next entry.
-	    dprev = dp;
-	    dp = dp->df_next;
-	}
-    }
-
-    dprev = NULL;
-    dp = tp->tp_first_diff;
-    while (dp != NULL)
-    {
-	// All counts are zero, remove this entry.
-	for (i = 0; i < DB_COUNT; ++i)
-	    if (tp->tp_diffbuf[i] != NULL && dp->df_count[i] != 0)
-		break;
-	if (i == DB_COUNT)
-	{
-	    dnext = dp->df_next;
-	    clear_diffblock(dp);
-	    dp = dnext;
-	    if (dprev == NULL)
-		tp->tp_first_diff = dnext;
-	    else
-		dprev->df_next = dnext;
-	}
-	else
-	{
-	    // Advance to next entry.
-	    dprev = dp;
-	    dp = dp->df_next;
-	}
-
-    }
-
-    if (tp == curtab)
-    {
-	// Don't redraw right away, this updates the diffs, which can be slow.
-	need_diff_redraw = TRUE;
-
-	// Need to recompute the scroll binding, may remove or add filler
-	// lines (e.g., when adding lines above w_topline). But it's slow when
-	// making many changes, postpone until redrawing.
-	diff_need_scrollbind = TRUE;
-    }
-}
-
-/*
- * Allocate a new diff block and link it between "dprev" and "dp".
- */
-    static diff_T *
-diff_alloc_new(tabpage_T *tp, diff_T *dprev, diff_T *dp)
-{
-    diff_T	*dnew;
-
-    dnew = ALLOC_CLEAR_ONE(diff_T);
-    if (dnew == NULL)
-	return NULL;
-
-    dnew->is_linematched = FALSE;
-    dnew->df_next = dp;
-    if (dprev == NULL)
-	tp->tp_first_diff = dnew;
-    else
-	dprev->df_next = dnew;
-
-    dnew->has_changes = FALSE;
-    ga_init2(&dnew->df_changes, sizeof(diffline_change_T), 20);
-    return dnew;
-}
-
-/*
- * Check if the diff block "dp" can be made smaller for lines at the start and
- * end that are equal.  Called after inserting lines.
- * This may result in a change where all buffers have zero lines, the caller
- * must take care of removing it.
- */
-    static void
-diff_check_unchanged(tabpage_T *tp, diff_T *dp)
-{
-    int		i_org;
-    int		i_new;
-    int		off_org, off_new;
-    char_u	*line_org;
-    int		dir = FORWARD;
-
-    // Find the first buffers, use it as the original, compare the other
-    // buffer lines against this one.
-    for (i_org = 0; i_org < DB_COUNT; ++i_org)
-	if (tp->tp_diffbuf[i_org] != NULL)
-	    break;
-    if (i_org == DB_COUNT)	// safety check
-	return;
-
-    if (diff_check_sanity(tp, dp) == FAIL)
-	return;
-
-    // First check lines at the top, then at the bottom.
-    off_org = 0;
-    off_new = 0;
-    for (;;)
-    {
-	// Repeat until a line is found which is different or the number of
-	// lines has become zero.
-	while (dp->df_count[i_org] > 0)
-	{
-	    // Copy the line, the next ml_get() will invalidate it.
-	    if (dir == BACKWARD)
-		off_org = dp->df_count[i_org] - 1;
-	    line_org = mnv_strsave(ml_get_buf(tp->tp_diffbuf[i_org],
-					dp->df_lnum[i_org] + off_org, FALSE));
-	    if (line_org == NULL)
-		return;
-	    for (i_new = i_org + 1; i_new < DB_COUNT; ++i_new)
-	    {
-		if (tp->tp_diffbuf[i_new] == NULL)
-		    continue;
-		if (dir == BACKWARD)
-		    off_new = dp->df_count[i_new] - 1;
-		// if other buffer doesn't have this line, it was inserted
-		if (off_new < 0 || off_new >= dp->df_count[i_new])
-		    break;
-		if (diff_cmp(line_org, ml_get_buf(tp->tp_diffbuf[i_new],
-				   dp->df_lnum[i_new] + off_new, FALSE)) != 0)
-		    break;
-	    }
-	    mnv_free(line_org);
-
-	    // Stop when a line isn't equal in all diff buffers.
-	    if (i_new != DB_COUNT)
-		break;
-
-	    // Line matched in all buffers, remove it from the diff.
-	    for (i_new = i_org; i_new < DB_COUNT; ++i_new)
-		if (tp->tp_diffbuf[i_new] != NULL)
-		{
-		    if (dir == FORWARD)
-			++dp->df_lnum[i_new];
-		    --dp->df_count[i_new];
-		}
-	}
-	if (dir == BACKWARD)
-	    break;
-	dir = BACKWARD;
-    }
-}
-
-/*
- * Check if a diff block doesn't contain invalid line numbers.
- * This can happen when the diff program returns invalid results.
- */
-    static int
-diff_check_sanity(tabpage_T *tp, diff_T *dp)
-{
-    int		i;
-
-    for (i = 0; i < DB_COUNT; ++i)
-	if (tp->tp_diffbuf[i] != NULL)
-	    if (dp->df_lnum[i] + dp->df_count[i] - 1
-				      > tp->tp_diffbuf[i]->b_ml.ml_line_count)
-		return FAIL;
-    return OK;
-}
-
-/*
- * Mark all diff buffers in the current tab page for redraw.
- */
-    void
-diff_redraw(
-    int		dofold)	    // also recompute the folds
-{
-    win_T	*wp;
-    win_T	*wp_other = NULL;
-    int		used_max_fill_other = FALSE;
-    int		used_max_fill_curwin = FALSE;
-    int		n;
-
-    need_diff_redraw = FALSE;
-    FOR_ALL_WINDOWS(wp)
-    {
-	// when closing windows or wiping buffers skip invalid window
-	if (!wp->w_p_diff || !buf_valid(wp->w_buffer))
-	    continue;
-
-	redraw_win_later(wp, UPD_SOME_VALID);
-	if (wp != curwin)
-	    wp_other = wp;
-# ifdef FEAT_FOLDING
-	if (dofold && foldmethodIsDiff(wp))
-	    foldUpdateAll(wp);
-# endif
-	// A change may have made filler lines invalid, need to take care of
-	// that for other windows.
-	n = diff_check_fill(wp, wp->w_topline);
-	if ((wp != curwin && wp->w_topfill > 0) || n > 0)
-	{
-	    if (wp->w_topfill > n)
-		wp->w_topfill = (n < 0 ? 0 : n);
-	    else if (n > 0 && n > wp->w_topfill)
-	    {
-		wp->w_topfill = n;
-		if (wp == curwin)
-		    used_max_fill_curwin = TRUE;
-		else if (wp_other != NULL)
-		    used_max_fill_other = TRUE;
-	    }
-	    check_topfill(wp, FALSE);
-	}
-    }
-
-    if (wp_other != NULL && curwin->w_p_scb)
-    {
-	if (used_max_fill_curwin)
-	    // The current window was set to use the maximum number of filler
-	    // lines, may need to reduce them.
-	    diff_set_topline(wp_other, curwin);
-	else if (used_max_fill_other)
-	    // The other window was set to use the maximum number of filler
-	    // lines, may need to reduce them.
-	    diff_set_topline(curwin, wp_other);
-    }
-}
-
-    static void
-clear_diffin(diffin_T *din)
-{
-    if (din->din_fname == NULL)
-	MNV_CLEAR(din->din_mmfile.ptr);
-    else
-	mch_remove(din->din_fname);
-}
-
-    static void
-clear_diffout(diffout_T *dout)
-{
-    if (dout->dout_fname == NULL)
-	ga_clear_strings(&dout->dout_ga);
-    else
-	mch_remove(dout->dout_fname);
-}
-
-/*
- * Write buffer "buf" to a memory buffer.
- * Return FAIL for failure.
- */
-    static int
-diff_write_buffer(buf_T *buf, diffin_T *din, linenr_T start, linenr_T end)
-{
-    linenr_T	lnum;
-    char_u	*s;
-    long	len = 0;
-    char_u	*ptr;
-
-    if (end < 0)
-	end = buf->b_ml.ml_line_count;
-
-    if (buf->b_ml.ml_flags & ML_EMPTY || end < start)
-    {
-	din->din_mmfile.ptr = NULL;
-	din->din_mmfile.size = 0;
-	return OK;
-    }
-
-    // xdiff requires one big block of memory with all the text.
-    for (lnum = start; lnum <= end; ++lnum)
-	len += ml_get_buf_len(buf, lnum) + 1;
-    ptr = alloc(len);
-    if (ptr == NULL)
-    {
-	// Allocating memory failed.  This can happen, because we try to read
-	// the whole buffer text into memory.  Set the failed flag, the diff
-	// will be retried with external diff.  The flag is never reset.
-	buf->b_diff_failed = TRUE;
-	if (p_verbose > 0)
-	{
-	    verbose_enter();
-	    smsg(_("Not enough memory to use internal diff for buffer \"%s\""),
-								 buf->b_fname);
-	    verbose_leave();
-	}
-	return FAIL;
-    }
-    din->din_mmfile.ptr = (char *)ptr;
-    din->din_mmfile.size = len;
-
-    len = 0;
-    for (lnum = start; lnum <= end; ++lnum)
-    {
-	for (s = ml_get_buf(buf, lnum, FALSE); *s != NUL; )
-	{
-	    if (diff_flags & DIFF_ICASE)
-	    {
-		int c;
-		int	orig_len;
-		int	c_len = 1;
-		char_u	cbuf[MB_MAXBYTES + 1];
-
-		if (*s == NL)
-		    c = NUL;
-		else
-		{
-		    // xdiff doesn't support ignoring case, fold-case the text.
-		    c = PTR2CHAR(s);
-		    c_len = MB_CHAR2LEN(c);
-		    c = MB_CASEFOLD(c);
-		}
-		orig_len = mb_ptr2len(s);
-		if (mb_char2bytes(c, cbuf) != c_len)
-		    // TODO: handle byte length difference.
-		    // One example is Å (3 bytes) and å (2 bytes).
-		    mch_memmove(ptr + len, s, orig_len);
-		else
-		{
-		    mch_memmove(ptr + len, cbuf, c_len);
-		    if (orig_len > c_len)
-		    {
-			// Copy remaining composing characters
-			mch_memmove(ptr + len + c_len, s + c_len,
-				orig_len - c_len);
-		    }
-		}
-
-		s += orig_len;
-		len += orig_len;
-	    }
-	    else
-	    {
-		ptr[len++] = *s == NL ? NUL : *s;
-		s++;
-	    }
-	}
-	ptr[len++] = NL;
-    }
-    return OK;
-}
-
-/*
- * Write buffer "buf" to file or memory buffer.
- * Return FAIL for failure.
- */
-    static int
-diff_write(buf_T *buf, diffin_T *din, linenr_T start, linenr_T end)
-{
-    int		r;
-    int		save_ml_flags;
-    char_u	*save_ff;
-    int		save_cmod_flags;
-
-    if (din->din_fname == NULL)
-	return diff_write_buffer(buf, din, start, end);
-
-    // Writing the diff buffers may trigger changes in the window structure
-    // via aucmd_prepbuf()/aucmd_restbuf() commands.
-    // This may cause recursively calling winframe_remove() which is not safe and causes
-    // use after free, so let's stop it here.
-    if (frames_locked())
-	return FAIL;
-
-    if (end < 0)
-	end = buf->b_ml.ml_line_count;
-
-    // Always use 'fileformat' set to "unix".
-    save_ml_flags = buf->b_ml.ml_flags;
-    save_ff = buf->b_p_ff;
-    buf->b_p_ff = mnv_strsave((char_u *)FF_UNIX);
-    save_cmod_flags = cmdmod.cmod_flags;
-    // Writing the buffer is an implementation detail of performing the diff,
-    // so it shouldn't update the '[ and '] marks.
-    cmdmod.cmod_flags |= CMOD_LOCKMARKS;
-    if (end < start)
-    {
-	// The line range specifies a completely empty file.
-	end = start;
-	buf->b_ml.ml_flags |= ML_EMPTY;
-    }
-    r = buf_write(buf, din->din_fname, NULL,
-			start, end,
-			NULL, FALSE, FALSE, FALSE, TRUE);
-    cmdmod.cmod_flags = save_cmod_flags;
-    free_string_option(buf->b_p_ff);
-    buf->b_p_ff = save_ff;
-    buf->b_ml.ml_flags =
-		(buf->b_ml.ml_flags & ~ML_EMPTY) | (save_ml_flags & ML_EMPTY);
-    return r;
-}
-
-    static int
-lnum_compare(const void *s1, const void *s2)
-{
-    linenr_T	lnum1 = *(linenr_T*)s1;
-    linenr_T	lnum2 = *(linenr_T*)s2;
-    if (lnum1 < lnum2)
-	return -1;
-    if (lnum1 > lnum2)
-	return 1;
-    return 0;
-}
-
-/*
- * Update the diffs for all buffers involved.
- */
-    static void
-diff_try_update(
-	diffio_T    *dio,
-	int	    idx_orig,
-	exarg_T	    *eap)	// "eap" can be NULL
-{
-    buf_T	*buf;
-    int		idx_new;
-
-    if (dio->dio_internal)
-    {
-	ga_init2(&dio->dio_diff.dout_ga, sizeof(char *), 1000);
-    }
-    else
-    {
-	// We need three temp file names.
-	dio->dio_orig.din_fname = mnv_tempname('o', TRUE);
-	dio->dio_new.din_fname = mnv_tempname('n', TRUE);
-	dio->dio_diff.dout_fname = mnv_tempname('d', TRUE);
-	if (dio->dio_orig.din_fname == NULL
-		|| dio->dio_new.din_fname == NULL
-		|| dio->dio_diff.dout_fname == NULL)
-	    goto theend;
-    }
-
-    // Check external diff is actually working.
-    if (!dio->dio_internal && check_external_diff(dio) == FAIL)
-	goto theend;
-
-    // :diffupdate!
-    if (eap != NULL && eap->forceit)
-	for (idx_new = idx_orig; idx_new < DB_COUNT; ++idx_new)
-	{
-	    buf = curtab->tp_diffbuf[idx_new];
-	    if (buf_valid(buf))
-		buf_check_timestamp(buf, FALSE);
-	}
-
-    // Parse and sort diff anchors if enabled
-    int num_anchors = INT_MAX;
-    linenr_T anchors[DB_COUNT][MAX_DIFF_ANCHORS];
-    CLEAR_FIELD(anchors);
-    if (diff_flags & DIFF_ANCHOR)
-    {
-	for (int idx = 0; idx < DB_COUNT; idx++)
-	{
-	    if (curtab->tp_diffbuf[idx] == NULL)
-		continue;
-	    int buf_num_anchors = 0;
-	    if (parse_diffanchors(FALSE,
-			curtab->tp_diffbuf[idx],
-			anchors[idx],
-			&buf_num_anchors) != OK)
-	    {
-		emsg(_(e_failed_to_find_all_diff_anchors));
-		num_anchors = 0;
-		CLEAR_FIELD(anchors);
-		break;
-	    }
-	    if (buf_num_anchors < num_anchors)
-		num_anchors = buf_num_anchors;
-
-	    if (buf_num_anchors > 0)
-		qsort((void *)anchors[idx],
-			(size_t)buf_num_anchors,
-			sizeof(linenr_T),
-			lnum_compare);
-	}
-    }
-    if (num_anchors == INT_MAX)
-	num_anchors = 0;
-
-    // Split the files into multiple sections by anchors. Each section starts
-    // from one anchor (inclusive) and ends at the next anchor (exclusive).
-    // Diff each section separately before combining the results. If we don't
-    // have any anchors, we will have one big section of the entire file.
-    for (int anchor_i = 0; anchor_i <= num_anchors; anchor_i++)
-    {
-	diff_T	*orig_diff = NULL;
-	if (anchor_i != 0)
-	{
-	    orig_diff = curtab->tp_first_diff;
-	    curtab->tp_first_diff = NULL;
-	}
-	linenr_T lnum_start = (anchor_i == 0) ? 1 : anchors[idx_orig][anchor_i - 1];
-	linenr_T lnum_end = (anchor_i == num_anchors) ? -1 : anchors[idx_orig][anchor_i] - 1;
-
-	// Write the first buffer to a tempfile or mmfile_t.
-	buf = curtab->tp_diffbuf[idx_orig];
-	if (diff_write(buf, &dio->dio_orig, lnum_start, lnum_end) == FAIL)
-	{
-	    if (orig_diff != NULL)
-	    {
-		// Clean up in-progress diff blocks
-		curtab->tp_first_diff = orig_diff;
-		diff_clear(curtab);
-	    }
-	    goto theend;
-	}
-
-	// Make a difference between the first buffer and every other.
-	for (idx_new = idx_orig + 1; idx_new < DB_COUNT; ++idx_new)
-	{
-	    buf = curtab->tp_diffbuf[idx_new];
-	    if (buf == NULL || buf->b_ml.ml_mfp == NULL)
-		continue; // skip buffer that isn't loaded
-
-	    lnum_start = anchor_i == 0 ? 1 : anchors[idx_new][anchor_i - 1];
-	    lnum_end = anchor_i == num_anchors ? -1 : anchors[idx_new][anchor_i] - 1;
-
-	    // Write the other buffer and diff with the first one.
-	    if (diff_write(buf, &dio->dio_new, lnum_start, lnum_end) == FAIL)
-		continue;
-	    if (diff_file(dio) == FAIL)
-		continue;
-
-	    // Read the diff output and add each entry to the diff list.
-	    diff_read(idx_orig, idx_new, dio);
-
-	    clear_diffin(&dio->dio_new);
-	    clear_diffout(&dio->dio_diff);
-	}
-	clear_diffin(&dio->dio_orig);
-
-	if (anchor_i != 0)
-	{
-	    // Combine the new diff blocks with the existing ones
-	    for (diff_T *dp = curtab->tp_first_diff; dp != NULL; dp = dp->df_next)
-	    {
-		for (int idx = 0; idx < DB_COUNT; idx++)
-		{
-		    if (anchors[idx][anchor_i - 1] > 0)
-			dp->df_lnum[idx] += anchors[idx][anchor_i - 1] - 1;
-		}
-	    }
-	    if (orig_diff != NULL)
-	    {
-		diff_T *last_diff = orig_diff;
-		while (last_diff->df_next != NULL)
-		    last_diff = last_diff->df_next;
-		last_diff->df_next = curtab->tp_first_diff;
-		curtab->tp_first_diff = orig_diff;
-	    }
-	}
-    }
-
-theend:
-    mnv_free(dio->dio_orig.din_fname);
-    mnv_free(dio->dio_new.din_fname);
-    mnv_free(dio->dio_diff.dout_fname);
-}
-
-/*
- * Return TRUE if the options are set to use the internal diff library.
- * Note that if the internal diff failed for one of the buffers, the external
- * diff will be used anyway.
- */
-    int
-diff_internal(void)
-{
-    return (diff_flags & DIFF_INTERNAL) != 0
-# ifdef FEAT_EVAL
-	&& *p_dex == NUL
-# endif
-	;
-}
-
-/*
- * Return TRUE if the internal diff failed for one of the diff buffers.
- */
-    static int
-diff_internal_failed(void)
-{
-    int idx;
-
-    // Only need to do something when there is another buffer.
-    for (idx = 0; idx < DB_COUNT; ++idx)
-	if (curtab->tp_diffbuf[idx] != NULL
-		&& curtab->tp_diffbuf[idx]->b_diff_failed)
-	    return TRUE;
-    return FALSE;
-}
-
-/*
- * Completely update the diffs for the buffers involved.
- * When using the external "diff" command the buffers are written to a file,
- * also for unmodified buffers (the file could have been produced by
- * autocommands, e.g. the netrw plugin).
- */
-    void
-ex_diffupdate(exarg_T *eap)	// "eap" can be NULL
-{
-    int		idx_orig;
-    int		idx_new;
-    diffio_T	diffio;
-    int		had_diffs = curtab->tp_first_diff != NULL;
-
-    if (diff_busy)
-    {
-	diff_need_update = TRUE;
-	return;
-    }
-
-    // Delete all diffblocks.
-    diff_clear(curtab);
-    curtab->tp_diff_invalid = FALSE;
-
-    // Use the first buffer as the original text.
-    for (idx_orig = 0; idx_orig < DB_COUNT; ++idx_orig)
-	if (curtab->tp_diffbuf[idx_orig] != NULL)
-	    break;
-    if (idx_orig == DB_COUNT)
-	goto theend;
-
-    // Only need to do something when there is another buffer.
-    for (idx_new = idx_orig + 1; idx_new < DB_COUNT; ++idx_new)
-	if (curtab->tp_diffbuf[idx_new] != NULL)
-	    break;
-    if (idx_new == DB_COUNT)
-	goto theend;
-
-    // Only use the internal method if it did not fail for one of the buffers.
-    CLEAR_FIELD(diffio);
-    diffio.dio_internal = diff_internal() && !diff_internal_failed();
-
-    diff_try_update(&diffio, idx_orig, eap);
-    if (diffio.dio_internal && diff_internal_failed())
-    {
-	// Internal diff failed, use external diff instead.
-	CLEAR_FIELD(diffio);
-	diff_try_update(&diffio, idx_orig, eap);
-    }
-
-    // force updating cursor position on screen
-    curwin->w_valid_cursor.lnum = 0;
-
-theend:
-    // A redraw is needed if there were diffs and they were cleared, or there
-    // are diffs now, which means they got updated.
-    if (had_diffs || curtab->tp_first_diff != NULL)
-    {
-	diff_redraw(TRUE);
-	apply_autocmds(EVENT_DIFFUPDATED, NULL, NULL, FALSE, curbuf);
-    }
-}
-
-/*
- * Do a quick test if "diff" really works.  Otherwise it looks like there
- * are no differences.  Can't use the return value, it's non-zero when
- * there are differences.
- */
-    static int
-check_external_diff(diffio_T *diffio)
-{
-    FILE	*fd;
-    int		ok;
-    int		io_error = FALSE;
-
-    // May try twice, first with "-a" and then without.
-    for (;;)
-    {
-	ok = FALSE;
-	fd = mch_fopen((char *)diffio->dio_orig.din_fname, "w");
-	if (fd == NULL)
-	    io_error = TRUE;
-	else
-	{
-	    if (fwrite("line1\n", (size_t)6, (size_t)1, fd) != 1)
-		io_error = TRUE;
-	    fclose(fd);
-	    fd = mch_fopen((char *)diffio->dio_new.din_fname, "w");
-	    if (fd == NULL)
-		io_error = TRUE;
-	    else
-	    {
-		if (fwrite("line2\n", (size_t)6, (size_t)1, fd) != 1)
-		    io_error = TRUE;
-		fclose(fd);
-		fd = NULL;
-		if (diff_file(diffio) == OK)
-		    fd = mch_fopen((char *)diffio->dio_diff.dout_fname, "r");
-		if (fd == NULL)
-		    io_error = TRUE;
-		else
-		{
-		    char_u	linebuf[LBUFLEN];
-
-		    for (;;)
-		    {
-			// For normal diff there must be a line that contains
-			// "1c1".  For unified diff "@@ -1 +1 @@".
-			if (mnv_fgets(linebuf, LBUFLEN, fd))
-			    break;
-			if (STRNCMP(linebuf, "1c1", 3) == 0
-				|| STRNCMP(linebuf, "@@ -1 +1 @@", 11) == 0)
-			    ok = TRUE;
-		    }
-		    fclose(fd);
-		}
-		mch_remove(diffio->dio_diff.dout_fname);
-		mch_remove(diffio->dio_new.din_fname);
-	    }
-	    mch_remove(diffio->dio_orig.din_fname);
-	}
-
-# ifdef FEAT_EVAL
-	// When using 'diffexpr' break here.
-	if (*p_dex != NUL)
-	    break;
-# endif
-
-# if defined(MSWIN)
-	// If the "-a" argument works, also check if "--binary" works.
-	if (ok && diff_a_works == MAYBE && diff_bin_works == MAYBE)
-	{
-	    diff_a_works = TRUE;
-	    diff_bin_works = TRUE;
-	    continue;
-	}
-	if (!ok && diff_a_works == TRUE && diff_bin_works == TRUE)
-	{
-	    // Tried --binary, but it failed. "-a" works though.
-	    diff_bin_works = FALSE;
-	    ok = TRUE;
-	}
-# endif
-
-	// If we checked if "-a" works already, break here.
-	if (diff_a_works != MAYBE)
-	    break;
-	diff_a_works = ok;
-
-	// If "-a" works break here, otherwise retry without "-a".
-	if (ok)
-	    break;
-    }
-    if (!ok)
-    {
-	if (io_error)
-	    emsg(_(e_cannot_read_or_write_temp_files));
-	emsg(_(e_cannot_create_diffs));
-	diff_a_works = MAYBE;
-# if defined(MSWIN)
-	diff_bin_works = MAYBE;
-# endif
-	return FAIL;
-    }
-    return OK;
-}
-
-/*
- * Invoke the xdiff function.
- */
-    static int
-diff_file_internal(diffio_T *diffio)
-{
-    xpparam_t	    param;
-    xdemitconf_t    emit_cfg;
-    xdemitcb_t	    emit_cb;
-
-    CLEAR_FIELD(param);
-    CLEAR_FIELD(emit_cfg);
-    CLEAR_FIELD(emit_cb);
-
-    param.flags = diff_algorithm;
-
-    if (diff_flags & DIFF_IWHITE)
-	param.flags |= XDF_IGNORE_WHITESPACE_CHANGE;
-    if (diff_flags & DIFF_IWHITEALL)
-	param.flags |= XDF_IGNORE_WHITESPACE;
-    if (diff_flags & DIFF_IWHITEEOL)
-	param.flags |= XDF_IGNORE_WHITESPACE_AT_EOL;
-    if (diff_flags & DIFF_IBLANK)
-	param.flags |= XDF_IGNORE_BLANK_LINES;
-
-    emit_cfg.ctxlen = diffio->dio_ctxlen;
-    emit_cb.priv = &diffio->dio_diff;
-    if (diffio->dio_outfmt == DIO_OUTPUT_INDICES)
-	emit_cfg.hunk_func = xdiff_out_indices;
-    else
-	emit_cb.out_line = xdiff_out_unified;
-    if (diffio->dio_orig.din_mmfile.size > MAX_XDIFF_SIZE ||
-	diffio->dio_new.din_mmfile.size > MAX_XDIFF_SIZE)
-    {
-	emsg(_(e_problem_creating_internal_diff));
-	return FAIL;
-    }
-    if (xdl_diff(&diffio->dio_orig.din_mmfile,
-		&diffio->dio_new.din_mmfile,
-		&param, &emit_cfg, &emit_cb) < 0)
-    {
-	emsg(_(e_problem_creating_internal_diff));
-	return FAIL;
-    }
-    return OK;
-}
-
-/*
- * Make a diff between files "tmp_orig" and "tmp_new", results in "tmp_diff".
- * return OK or FAIL;
- */
-    static int
-diff_file(diffio_T *dio)
-{
-    char_u	*cmd;
-    size_t	len;
-    char_u	*tmp_orig = dio->dio_orig.din_fname;
-    char_u	*tmp_new = dio->dio_new.din_fname;
-    char_u	*tmp_diff = dio->dio_diff.dout_fname;
-
-# ifdef FEAT_EVAL
-    if (*p_dex != NUL)
-    {
-	// Use 'diffexpr' to generate the diff file.
-	eval_diff(tmp_orig, tmp_new, tmp_diff);
-	return OK;
-    }
-    else
-# endif
-    // Use xdiff for generating the diff.
-    if (dio->dio_internal)
-	return diff_file_internal(dio);
-
-    if (check_restricted())
-	return FAIL;
-
-    len = STRLEN(tmp_orig) + STRLEN(tmp_new)
-				+ STRLEN(tmp_diff) + STRLEN(p_srr) + 27;
-    cmd = alloc(len);
-    if (cmd == NULL)
-	return FAIL;
-
-    // We don't want $DIFF_OPTIONS to get in the way.
-    if (getenv("DIFF_OPTIONS"))
-	mnv_setenv((char_u *)"DIFF_OPTIONS", (char_u *)"");
-
-    // Build the diff command and execute it.  Always use -a, binary
-    // differences are of no use.  Ignore errors, diff returns
-    // non-zero when differences have been found.
-    mnv_snprintf((char *)cmd, len, "diff %s%s%s%s%s%s%s%s %s",
-	    diff_a_works == FALSE ? "" : "-a ",
-# if defined(MSWIN)
-	    diff_bin_works == TRUE ? "--binary " : "",
-# else
-	    "",
-# endif
-	    (diff_flags & DIFF_IWHITE) ? "-b " : "",
-	    (diff_flags & DIFF_IWHITEALL) ? "-w " : "",
-	    (diff_flags & DIFF_IWHITEEOL) ? "-Z " : "",
-	    (diff_flags & DIFF_IBLANK) ? "-B " : "",
-	    (diff_flags & DIFF_ICASE) ? "-i " : "",
-	    tmp_orig, tmp_new);
-    append_redir(cmd, (int)len, p_srr, tmp_diff);
-    block_autocmds();	// avoid ShellCmdPost stuff
-    (void)call_shell(cmd, SHELL_FILTER|SHELL_SILENT|SHELL_DOOUT);
-    unblock_autocmds();
-    mnv_free(cmd);
-    return OK;
-}
-
-/*
- * Create a new version of a file from the current buffer and a diff file.
- * The buffer is written to a file, also for unmodified buffers (the file
- * could have been produced by autocommands, e.g. the netrw plugin).
- */
-    void
-ex_diffpatch(exarg_T *eap)
-{
-    char_u	*tmp_orig;	// name of original temp file
-    char_u	*tmp_new;	// name of patched temp file
-    char_u	*buf = NULL;
-    size_t	buflen;
-    win_T	*old_curwin = curwin;
-    char_u	*newname = NULL;	// name of patched file buffer
-# ifdef UNIX
-    char_u	dirbuf[MAXPATHL];
-    char_u	*fullname = NULL;
-# endif
-# ifdef FEAT_BROWSE
-    char_u	*browseFile = NULL;
-    int		save_cmod_flags = cmdmod.cmod_flags;
-# endif
-    stat_T	st;
-    char_u	*esc_name = NULL;
-
-# ifdef FEAT_BROWSE
-    if (cmdmod.cmod_flags & CMOD_BROWSE)
-    {
-	browseFile = do_browse(0, (char_u *)_("Patch file"),
-			 eap->arg, NULL, NULL,
-			 (char_u *)_(BROWSE_FILTER_ALL_FILES), NULL);
-	if (browseFile == NULL)
-	    return;		// operation cancelled
-	eap->arg = browseFile;
-	cmdmod.cmod_flags &= ~CMOD_BROWSE; // don't let do_ecmd() browse again
-    }
-# endif
-
-    // We need two temp file names.
-    tmp_orig = mnv_tempname('o', FALSE);
-    tmp_new = mnv_tempname('n', FALSE);
-    if (tmp_orig == NULL || tmp_new == NULL)
-	goto theend;
-
-    // Write the current buffer to "tmp_orig".
-    if (buf_write(curbuf, tmp_orig, NULL,
-		(linenr_T)1, curbuf->b_ml.ml_line_count,
-				     NULL, FALSE, FALSE, FALSE, TRUE) == FAIL)
-	goto theend;
-
-# ifdef UNIX
-    // Get the absolute path of the patchfile, changing directory below.
-    fullname = FullName_save(eap->arg, FALSE);
-# endif
-    esc_name = mnv_strsave_shellescape(
-# ifdef UNIX
-		    fullname != NULL ? fullname :
-# endif
-		    eap->arg, TRUE, TRUE);
-    if (esc_name == NULL)
-	goto theend;
-    buflen = STRLEN(tmp_orig) + STRLEN(esc_name) + STRLEN(tmp_new) + 16;
-    buf = alloc(buflen);
-    if (buf == NULL)
-	goto theend;
-
-# ifdef UNIX
-    // Temporarily chdir to /tmp, to avoid patching files in the current
-    // directory when the patch file contains more than one patch.  When we
-    // have our own temp dir use that instead, it will be cleaned up when we
-    // exit (any .rej files created).  Don't change directory if we can't
-    // return to the current.
-    if (mch_dirname(dirbuf, MAXPATHL) != OK || mch_chdir((char *)dirbuf) != 0)
-	dirbuf[0] = NUL;
-    else
-    {
-#  ifdef TEMPDIRNAMES
-	if (mnv_tempdir != NULL)
-	    mnv_ignored = mch_chdir((char *)mnv_tempdir);
-	else
-#  endif
-	    mnv_ignored = mch_chdir("/tmp");
-	shorten_fnames(TRUE);
-    }
-# endif
-
-# ifdef FEAT_EVAL
-    if (*p_pex != NUL)
-	// Use 'patchexpr' to generate the new file.
-	eval_patch(tmp_orig,
-#  ifdef UNIX
-		fullname != NULL ? fullname :
-#  endif
-		eap->arg, tmp_new);
-    else
-# endif
-    {
-	if (check_restricted())
-	    goto theend;
-
-	// Build the patch command and execute it.  Ignore errors.  Switch to
-	// cooked mode to allow the user to respond to prompts.
-	mnv_snprintf((char *)buf, buflen, "patch -o %s %s < %s",
-						  tmp_new, tmp_orig, esc_name);
-	block_autocmds();	// Avoid ShellCmdPost stuff
-	(void)call_shell(buf, SHELL_FILTER | SHELL_COOKED);
-	unblock_autocmds();
-    }
-
-# ifdef UNIX
-    if (dirbuf[0] != NUL)
-    {
-	if (mch_chdir((char *)dirbuf) != 0)
-	    emsg(_(e_cannot_go_back_to_previous_directory));
-	shorten_fnames(TRUE);
-    }
-# endif
-
-    // patch probably has written over the screen
-    redraw_later(UPD_CLEAR);
-
-    // Delete any .orig or .rej file created.
-    STRCPY(buf, tmp_new);
-    STRCAT(buf, ".orig");
-    mch_remove(buf);
-    STRCPY(buf, tmp_new);
-    STRCAT(buf, ".rej");
-    mch_remove(buf);
-
-    // Only continue if the output file was created.
-    if (mch_stat((char *)tmp_new, &st) < 0 || st.st_size == 0)
-	emsg(_(e_cannot_read_patch_output));
-    else
-    {
-	if (curbuf->b_fname != NULL)
-	{
-	    newname = mnv_strnsave(curbuf->b_fname,
-						  STRLEN(curbuf->b_fname) + 4);
-	    if (newname != NULL)
-		STRCAT(newname, ".new");
-	}
-
-# ifdef FEAT_GUI
-	need_mouse_correct = TRUE;
-# endif
-	// don't use a new tab page, each tab page has its own diffs
-	cmdmod.cmod_tab = 0;
-
-	if (win_split(0, (diff_flags & DIFF_VERTICAL) ? WSP_VERT : 0) != FAIL)
-	{
-	    // Pretend it was a ":split fname" command
-	    eap->cmdidx = CMD_split;
-	    eap->arg = tmp_new;
-	    do_exedit(eap, old_curwin);
-
-	    // check that split worked and editing tmp_new
-	    if (curwin != old_curwin && win_valid(old_curwin))
-	    {
-		// Set 'diff', 'scrollbind' on and 'wrap' off.
-		diff_win_options(curwin, TRUE);
-		diff_win_options(old_curwin, TRUE);
-
-		if (newname != NULL)
-		{
-		    // do a ":file filename.new" on the patched buffer
-		    eap->arg = newname;
-		    ex_file(eap);
-
-		    // Do filetype detection with the new name.
-		    if (au_has_group((char_u *)"filetypedetect"))
-			do_cmdline_cmd(
-				     (char_u *)":doau filetypedetect BufRead");
-		}
-	    }
-	}
-    }
-
-theend:
-    if (tmp_orig != NULL)
-	mch_remove(tmp_orig);
-    mnv_free(tmp_orig);
-    if (tmp_new != NULL)
-	mch_remove(tmp_new);
-    mnv_free(tmp_new);
-    mnv_free(newname);
-    mnv_free(buf);
-# ifdef UNIX
-    mnv_free(fullname);
-# endif
-    mnv_free(esc_name);
-# ifdef FEAT_BROWSE
-    mnv_free(browseFile);
-    cmdmod.cmod_flags = save_cmod_flags;
-# endif
-}
-
-/*
- * Split the window and edit another file, setting options to show the diffs.
- */
-    void
-ex_diffsplit(exarg_T *eap)
-{
-    win_T	*old_curwin = curwin;
-    bufref_T	old_curbuf;
-
-    set_bufref(&old_curbuf, curbuf);
-# ifdef FEAT_GUI
-    need_mouse_correct = TRUE;
-# endif
-    // Need to compute w_fraction when no redraw happened yet.
-    validate_cursor();
-    set_fraction(curwin);
-
-    // don't use a new tab page, each tab page has its own diffs
-    cmdmod.cmod_tab = 0;
-
-    if (win_split(0, (diff_flags & DIFF_VERTICAL) ? WSP_VERT : 0) == FAIL)
-	return;
-
-    // Pretend it was a ":split fname" command
-    eap->cmdidx = CMD_split;
-    curwin->w_p_diff = TRUE;
-    do_exedit(eap, old_curwin);
-
-    if (curwin == old_curwin)		// split didn't work
-	return;
-
-    // Set 'diff', 'scrollbind' on and 'wrap' off.
-    diff_win_options(curwin, TRUE);
-    if (win_valid(old_curwin))
-    {
-	diff_win_options(old_curwin, TRUE);
-
-	if (bufref_valid(&old_curbuf))
-	    // Move the cursor position to that of the old window.
-	    curwin->w_cursor.lnum = diff_get_corresponding_line(
-		    old_curbuf.br_buf, old_curwin->w_cursor.lnum);
-    }
-    // Now that lines are folded scroll to show the cursor at the same
-    // relative position.
-    scroll_to_fraction(curwin, curwin->w_height);
-}
-
-/*
- * Set options to show diffs for the current window.
- */
-    void
-ex_diffthis(exarg_T *eap UNUSED)
-{
-    // Set 'diff', 'scrollbind' on and 'wrap' off.
-    diff_win_options(curwin, TRUE);
-}
-
-    static void
-set_diff_option(win_T *wp, int value)
-{
-    win_T *old_curwin = curwin;
-
-    curwin = wp;
-    curbuf = curwin->w_buffer;
-    ++curbuf_lock;
-    set_option_value_give_err((char_u *)"diff", (long)value, NULL, OPT_LOCAL);
-    --curbuf_lock;
-    curwin = old_curwin;
-    curbuf = curwin->w_buffer;
-}
-
-/*
- * Set options in window "wp" for diff mode.
- */
-    void
-diff_win_options(
-    win_T	*wp,
-    int		addbuf)		// Add buffer to diff.
-{
-# ifdef FEAT_FOLDING
-    win_T *old_curwin = curwin;
-
-    // close the manually opened folds
-    curwin = wp;
-    newFoldLevel();
-    curwin = old_curwin;
-# endif
-
-    // Use 'scrollbind' and 'cursorbind' when available
-    if (!wp->w_p_diff)
-	wp->w_p_scb_save = wp->w_p_scb;
-    wp->w_p_scb = TRUE;
-    if (!wp->w_p_diff)
-	wp->w_p_crb_save = wp->w_p_crb;
-    wp->w_p_crb = TRUE;
-    if (!(diff_flags & DIFF_FOLLOWWRAP))
-    {
-	if (!wp->w_p_diff)
-	    wp->w_p_wrap_save = wp->w_p_wrap;
-	wp->w_p_wrap = FALSE;
-	wp->w_skipcol = 0;
-    }
-# ifdef FEAT_FOLDING
-    if (!wp->w_p_diff)
-    {
-	if (wp->w_p_diff_saved)
-	    free_string_option(wp->w_p_fdm_save);
-	wp->w_p_fdm_save = mnv_strsave(wp->w_p_fdm);
-    }
-    set_string_option_direct_in_win(wp, (char_u *)"fdm", -1, (char_u *)"diff",
-						       OPT_LOCAL|OPT_FREE, 0);
-    if (!wp->w_p_diff)
-    {
-	wp->w_p_fdc_save = wp->w_p_fdc;
-	wp->w_p_fen_save = wp->w_p_fen;
-	wp->w_p_fdl_save = wp->w_p_fdl;
-    }
-    wp->w_p_fdc = diff_foldcolumn;
-    wp->w_p_fen = TRUE;
-    wp->w_p_fdl = 0;
-    foldUpdateAll(wp);
-    // make sure topline is not halfway a fold
-    changed_window_setting_win(wp);
-# endif
-    if (mnv_strchr(p_sbo, 'h') == NULL)
-	do_cmdline_cmd((char_u *)"set sbo+=hor");
-    // Save the current values, to be restored in ex_diffoff().
-    wp->w_p_diff_saved = TRUE;
-
-    set_diff_option(wp, TRUE);
-
-    if (addbuf)
-	diff_buf_add(wp->w_buffer);
-    redraw_win_later(wp, UPD_NOT_VALID);
-}
-
-/*
- * Set options not to show diffs.  For the current window or all windows.
- * Only in the current tab page.
- */
-    void
-ex_diffoff(exarg_T *eap)
-{
-    win_T	*wp;
-    int		diffwin = FALSE;
-
-    FOR_ALL_WINDOWS(wp)
-    {
-	if (eap->forceit ? wp->w_p_diff : wp == curwin)
-	{
-	    // Set 'diff' off. If option values were saved in
-	    // diff_win_options(), restore the ones whose settings seem to have
-	    // been left over from diff mode.
-	    set_diff_option(wp, FALSE);
-
-	    if (wp->w_p_diff_saved)
-	    {
-
-		if (wp->w_p_scb)
-		    wp->w_p_scb = wp->w_p_scb_save;
-		if (wp->w_p_crb)
-		    wp->w_p_crb = wp->w_p_crb_save;
-		if (!(diff_flags & DIFF_FOLLOWWRAP))
-		{
-		    if (!wp->w_p_wrap && wp->w_p_wrap_save)
-		    {
-			wp->w_p_wrap = TRUE;
-			wp->w_leftcol = 0;
-		    }
-		}
-# ifdef FEAT_FOLDING
-		free_string_option(wp->w_p_fdm);
-		wp->w_p_fdm = mnv_strsave(
-		    *wp->w_p_fdm_save ? wp->w_p_fdm_save : (char_u*)"manual");
-
-		if (wp->w_p_fdc == diff_foldcolumn)
-		    wp->w_p_fdc = wp->w_p_fdc_save;
-		if (wp->w_p_fdl == 0)
-		    wp->w_p_fdl = wp->w_p_fdl_save;
-
-		// Only restore 'foldenable' when 'foldmethod' is not
-		// "manual", otherwise we continue to show the diff folds.
-		if (wp->w_p_fen)
-		    wp->w_p_fen = foldmethodIsManual(wp) ? FALSE
-							 : wp->w_p_fen_save;
-
-		foldUpdateAll(wp);
-# endif
-	    }
-	    // remove filler lines
-	    wp->w_topfill = 0;
-
-	    // make sure topline is not halfway a fold and cursor is
-	    // invalidated
-	    changed_window_setting_win(wp);
-
-	    // Note: 'sbo' is not restored, it's a global option.
-	    diff_buf_adjust(wp);
-	}
-	diffwin |= wp->w_p_diff;
-    }
-
-    // Also remove hidden buffers from the list.
-    if (eap->forceit)
-	diff_buf_clear();
-
-    if (!diffwin)
-    {
-	diff_need_update = FALSE;
-	curtab->tp_diff_invalid = FALSE;
-	curtab->tp_diff_update = FALSE;
-	diff_clear(curtab);
-    }
-
-    // Remove "hor" from 'scrollopt' if there are no diff windows left.
-    if (!diffwin && mnv_strchr(p_sbo, 'h') != NULL)
-	do_cmdline_cmd((char_u *)"set sbo-=hor");
-}
-
-/*
- * Read the diff output and add each entry to the diff list.
- */
-    static void
-diff_read(
-    int		idx_orig,	// idx of original file
-    int		idx_new,	// idx of new file
-    diffio_T   *dio)		// diff output
-{
-    FILE	*fd = NULL;
-    int		line_hunk_idx = 0;  // line or hunk index
-    diff_T	*dprev = NULL;
-    diff_T	*dp = curtab->tp_first_diff;
-    diff_T	*dn, *dpl;
-    diffout_T   *dout = &dio->dio_diff;
-    char_u	linebuf[LBUFLEN];   // only need to hold the diff line
-    char_u	*line;
-    long	off;
-    int		i;
-    int		notset = TRUE;	    // block "*dp" not set yet
-    diffhunk_T	*hunk = NULL;	    // init to avoid gcc warning
-
-    enum {
-	DIFF_ED,
-	DIFF_UNIFIED,
-	DIFF_NONE
-    } diffstyle = DIFF_NONE;
-
-    if (dout->dout_fname == NULL)
-    {
-	diffstyle = DIFF_UNIFIED;
-    }
-    else
-    {
-	fd = mch_fopen((char *)dout->dout_fname, "r");
-	if (fd == NULL)
-	{
-	    emsg(_(e_cannot_read_diff_output));
-	    return;
-	}
-    }
-
-    if (!dio->dio_internal)
-    {
-	hunk = ALLOC_ONE(diffhunk_T);
-	if (hunk == NULL)
-	{
-	    if (fd != NULL)
-		fclose(fd);
-	    return;
-	}
-    }
-
-    for (;;)
-    {
-	if (dio->dio_internal)
-	{
-	    if (line_hunk_idx >= dout->dout_ga.ga_len)
-		break;      // did last hunk
-	    hunk = ((diffhunk_T **)dout->dout_ga.ga_data)[line_hunk_idx++];
-	}
-	else
-	{
-	    if (fd == NULL)
-	    {
-		if (line_hunk_idx >= dout->dout_ga.ga_len)
-		    break;	    // did last line
-		line = ((char_u **)dout->dout_ga.ga_data)[line_hunk_idx++];
-	    }
-	    else
-	    {
-		if (mnv_fgets(linebuf, LBUFLEN, fd))
-		    break;		// end of file
-		line = linebuf;
-	    }
-
-	    if (diffstyle == DIFF_NONE)
-	    {
-		// Determine diff style.
-		// ed like diff looks like this:
-		// {first}[,{last}]c{first}[,{last}]
-		// {first}a{first}[,{last}]
-		// {first}[,{last}]d{first}
-		//
-		// unified diff looks like this:
-		// --- file1       2018-03-20 13:23:35.783153140 +0100
-		// +++ file2       2018-03-20 13:23:41.183156066 +0100
-		// @@ -1,3 +1,5 @@
-		if (SAFE_isdigit(*line))
-		    diffstyle = DIFF_ED;
-		else if ((STRNCMP(line, "@@ ", 3) == 0))
-		    diffstyle = DIFF_UNIFIED;
-		else if ((STRNCMP(line, "--- ", 4) == 0)
-			&& (mnv_fgets(linebuf, LBUFLEN, fd) == 0)
-			&& (STRNCMP(line, "+++ ", 4) == 0)
-			&& (mnv_fgets(linebuf, LBUFLEN, fd) == 0)
-			&& (STRNCMP(line, "@@ ", 3) == 0))
-		    diffstyle = DIFF_UNIFIED;
-		else
-		    // Format not recognized yet, skip over this line.  Cygwin
-		    // diff may put a warning at the start of the file.
-		    continue;
-	    }
-
-	    if (diffstyle == DIFF_ED)
-	    {
-		if (!SAFE_isdigit(*line))
-		    continue;	// not the start of a diff block
-		if (parse_diff_ed(line, hunk) == FAIL)
-		    continue;
-	    }
-	    else if (diffstyle == DIFF_UNIFIED)
-	    {
-		if (STRNCMP(line, "@@ ", 3)  != 0)
-		    continue;	// not the start of a diff block
-		if (parse_diff_unified(line, hunk) == FAIL)
-		    continue;
-	    }
-	    else
-	    {
-		emsg(_(e_invalid_diff_format));
-		break;
-	    }
-	}
-
-	// Go over blocks before the change, for which orig and new are equal.
-	// Copy blocks from orig to new.
-	while (dp != NULL
-		&& hunk->lnum_orig > dp->df_lnum[idx_orig]
-						      + dp->df_count[idx_orig])
-	{
-	    if (notset)
-		diff_copy_entry(dprev, dp, idx_orig, idx_new);
-	    dprev = dp;
-	    dp = dp->df_next;
-	    notset = TRUE;
-	}
-
-	if (dp != NULL
-		&& hunk->lnum_orig <= dp->df_lnum[idx_orig]
-						       + dp->df_count[idx_orig]
-		&& hunk->lnum_orig + hunk->count_orig >= dp->df_lnum[idx_orig])
-	{
-	    // New block overlaps with existing block(s).
-	    // First find last block that overlaps.
-	    for (dpl = dp; dpl->df_next != NULL; dpl = dpl->df_next)
-		if (hunk->lnum_orig + hunk->count_orig
-					     < dpl->df_next->df_lnum[idx_orig])
-		    break;
-
-	    // If the newly found block starts before the old one, set the
-	    // start back a number of lines.
-	    off = dp->df_lnum[idx_orig] - hunk->lnum_orig;
-	    if (off > 0)
-	    {
-		for (i = idx_orig; i < idx_new; ++i)
-		    if (curtab->tp_diffbuf[i] != NULL)
-		    {
-			dp->df_lnum[i] -= off;
-			dp->df_count[i] += off;
-		    }
-		dp->df_lnum[idx_new] = hunk->lnum_new;
-		dp->df_count[idx_new] = hunk->count_new;
-	    }
-	    else if (notset)
-	    {
-		// new block inside existing one, adjust new block
-		dp->df_lnum[idx_new] = hunk->lnum_new + off;
-		dp->df_count[idx_new] = hunk->count_new - off;
-	    }
-	    else
-	    {
-		// second overlap of new block with existing block
-
-		// if this hunk has different orig/new counts, adjust
-		// the diff block size first. When we handled the first hunk we
-		// would have expanded it to fit, without knowing that this
-		// hunk exists
-		int orig_size_in_dp = MIN(hunk->count_orig,
-			dp->df_lnum[idx_orig] +
-			dp->df_count[idx_orig] - hunk->lnum_orig);
-		int size_diff = hunk->count_new - orig_size_in_dp;
-		dp->df_count[idx_new] += size_diff;
-
-		// grow existing block to include the overlap completely
-		off = hunk->lnum_new + hunk->count_new
-		    - (dp->df_lnum[idx_new] + dp->df_count[idx_new]);
-		if (off > 0)
-		    dp->df_count[idx_new] += off;
-	    }
-
-	    // Adjust the size of the block to include all the lines to the
-	    // end of the existing block or the new diff, whatever ends last.
-	    off = (hunk->lnum_orig + hunk->count_orig)
-			 - (dpl->df_lnum[idx_orig] + dpl->df_count[idx_orig]);
-	    if (off < 0)
-	    {
-		// new change ends in existing block, adjust the end. We only
-		// need to do this once per block or we will over-adjust.
-		if (notset || dp != dpl)
-		{
-		    // adjusting by 'off' here is only correct if
-		    // there is not another hunk in this block. we
-		    // adjust for this when we encounter a second
-		    // overlap later.
-		    dp->df_count[idx_new] += -off;
-		}
-		off = 0;
-	    }
-	    for (i = idx_orig; i < idx_new; ++i)
-		if (curtab->tp_diffbuf[i] != NULL)
-		    dp->df_count[i] = dpl->df_lnum[i] + dpl->df_count[i]
-						       - dp->df_lnum[i] + off;
-
-	    // Delete the diff blocks that have been merged into one.
-	    dn = dp->df_next;
-	    dp->df_next = dpl->df_next;
-	    while (dn != dp->df_next)
-	    {
-		dpl = dn->df_next;
-		clear_diffblock(dn);
-		dn = dpl;
-	    }
-	}
-	else
-	{
-	    // Allocate a new diffblock.
-	    dp = diff_alloc_new(curtab, dprev, dp);
-	    if (dp == NULL)
-		goto done;
-
-	    dp->df_lnum[idx_orig] = hunk->lnum_orig;
-	    dp->df_count[idx_orig] = hunk->count_orig;
-	    dp->df_lnum[idx_new] = hunk->lnum_new;
-	    dp->df_count[idx_new] = hunk->count_new;
-
-	    // Set values for other buffers, these must be equal to the
-	    // original buffer, otherwise there would have been a change
-	    // already.
-	    for (i = idx_orig + 1; i < idx_new; ++i)
-		if (curtab->tp_diffbuf[i] != NULL)
-		    diff_copy_entry(dprev, dp, idx_orig, i);
-	}
-	notset = FALSE;		// "*dp" has been set
-    }
-
-    // for remaining diff blocks orig and new are equal
-    while (dp != NULL)
-    {
-	if (notset)
-	    diff_copy_entry(dprev, dp, idx_orig, idx_new);
-	dprev = dp;
-	dp = dp->df_next;
-	notset = TRUE;
-    }
-
-done:
-    if (!dio->dio_internal)
-	mnv_free(hunk);
-
-    if (fd != NULL)
-	fclose(fd);
-}
-
-/*
- * Copy an entry at "dp" from "idx_orig" to "idx_new".
- */
-    static void
-diff_copy_entry(
-    diff_T	*dprev,
-    diff_T	*dp,
-    int		idx_orig,
-    int		idx_new)
-{
-    long	off;
-
-    if (dprev == NULL)
-	off = 0;
-    else
-	off = (dprev->df_lnum[idx_orig] + dprev->df_count[idx_orig])
-	    - (dprev->df_lnum[idx_new] + dprev->df_count[idx_new]);
-    dp->df_lnum[idx_new] = dp->df_lnum[idx_orig] - off;
-    dp->df_count[idx_new] = dp->df_count[idx_orig];
-}
-
-/*
- * Clear the list of diffblocks for tab page "tp".
- */
-    void
-diff_clear(tabpage_T *tp)
-{
-    diff_T	*p, *next_p;
-
-    for (p = tp->tp_first_diff; p != NULL; p = next_p)
-    {
-	next_p = p->df_next;
-	clear_diffblock(p);
-    }
-    tp->tp_first_diff = NULL;
-}
-
-/*
- *  return true if the options are set to use diff linematch
- */
-    static int
-diff_linematch(diff_T *dp)
-{
-    if (!(diff_flags & DIFF_LINEMATCH))
-	return 0;
-
-    // are there more than three diff buffers?
-    int tsize = 0;
-    for (int i = 0; i < DB_COUNT; i++)
-    {
-	if (curtab->tp_diffbuf[i] != NULL)
-	{
-	    // for the rare case (bug?) that the count of a diff block is
-	    // negative, do not run the algorithm because this will try to
-	    // allocate a negative amount of space and crash
-	    if (dp->df_count[i] < 0)
-		return FALSE;
-	    tsize += dp->df_count[i];
-	}
-    }
-
-    // avoid allocating a huge array because it will lag
-    return tsize <= linematch_lines;
-}
-
-    static int
-get_max_diff_length(const diff_T *dp)
-{
-    int maxlength = 0;
-
-    for (int k = 0; k < DB_COUNT; k++)
-    {
-	if (curtab->tp_diffbuf[k] != NULL)
-	{
-	    if (dp->df_count[k] > maxlength)
-		maxlength = dp->df_count[k];
-	}
-    }
-    return maxlength;
-}
-
-/*
- * Find the first diff block that includes the specified line. Also find the
- * next diff block that's not in the current chain of adjacent blocks that are
- * all touching each other directly.
- */
-    static void
-find_top_diff_block(
-    diff_T	**thistopdiff,
-    diff_T	**next_adjacent_blocks,
-    int		fromidx,
-    int		topline)
-{
-    diff_T	*topdiff = NULL;
-    diff_T	*localtopdiff = NULL;
-    int		topdiffchange = 0;
-
-    for (topdiff = curtab->tp_first_diff; topdiff != NULL;
-						topdiff = topdiff->df_next)
-    {
-	// set the top of the current overlapping diff block set as we
-	// iterate through all of the sets of overlapping diff blocks
-	if (!localtopdiff || topdiffchange)
-	{
-	    localtopdiff = topdiff;
-	    topdiffchange = 0;
-	}
-
-	// check if the fromwin topline is matched by the current diff. if so,
-	// set it to the top of the diff block
-	if (topline >= topdiff->df_lnum[fromidx] && topline <=
-		(topdiff->df_lnum[fromidx] + topdiff->df_count[fromidx]))
-	{
-	    // this line is inside the current diff block, so we will save the
-	    // top block of the set of blocks to refer to later
-	    if ((*thistopdiff) == NULL)
-		(*thistopdiff) = localtopdiff;
-	}
-
-	// check if the next set of overlapping diff blocks is next
-	if (!(topdiff->df_next && (topdiff->df_next->df_lnum[fromidx] ==
-			(topdiff->df_lnum[fromidx] +
-						topdiff->df_count[fromidx]))))
-	{
-	    // mark that the next diff block is belongs to a different set of
-	    // overlapping diff blocks
-	    topdiffchange = 1;
-
-	    // if we already have found that the line number is inside a diff
-	    // block, set the marker of the next block and finish the iteration
-	    if (*thistopdiff)
-	    {
-		(*next_adjacent_blocks) = topdiff->df_next;
-		break;
-	    }
-	}
-    }
-}
-
-/*
- * Calculates topline/topfill of a target diff window to fit the source diff
- * window.
- */
-    static void
-calculate_topfill_and_topline(
-    const int	fromidx,
-    const int	toidx,
-    const int	from_topline,
-    const int	from_topfill,
-    int		*topfill,
-    linenr_T	*topline)
-{
-    // find the position from the top of the diff block, and the next diff
-    // block that's no longer adjacent to the current block. "Adjacency" means
-    // a chain of diff blocks that are directly touching each other, allowed by
-    // linematch and diff anchors.
-    diff_T	*thistopdiff = NULL;
-    diff_T	*next_adjacent_blocks = NULL;
-    int		virtual_lines_passed = 0;
-    int		curlinenum_to = 1;
-
-    find_top_diff_block(&thistopdiff, &next_adjacent_blocks, fromidx, from_topline);
-
-    // count the virtual lines (either filler or concrete line) that have been
-    // passed in the source buffer. There could be multiple diff blocks if
-    // there are adjacent empty blocks (count == 0 at fromidx).
-    diff_T *curdif = thistopdiff;
-    while (curdif && (curdif->df_lnum[fromidx] + curdif->df_count[fromidx])
-							<= from_topline)
-    {
-	virtual_lines_passed += get_max_diff_length(curdif);
-
-	curdif = curdif->df_next;
-    }
-
-    if (curdif != next_adjacent_blocks)
-	virtual_lines_passed += from_topline - curdif->df_lnum[fromidx];
-    virtual_lines_passed -= from_topfill;
-
-    // clamp negative values in case from_topfill hasn't been updated yet and
-    // is larger than total virtual lines, which could happen when setting
-    // diffopt multiple times
-    if (virtual_lines_passed < 0)
-	virtual_lines_passed = 0;
-
-    // move the same amount of virtual lines in the target buffer to find the
-    // cursor's line number
-    if (thistopdiff != NULL) // this should not be null, but just for safety
-	curlinenum_to = thistopdiff->df_lnum[toidx];
-
-    int virt_lines_left = virtual_lines_passed;
-    curdif = thistopdiff;
-    while (virt_lines_left > 0 && curdif != NULL && curdif != next_adjacent_blocks)
-    {
-	curlinenum_to += MIN(virt_lines_left, curdif->df_count[toidx]);
-	virt_lines_left -= MIN(virt_lines_left, get_max_diff_length(curdif));
-	curdif = curdif->df_next;
-    }
-
-    // count the total number of virtual lines between the top diff block and
-    // the found line in the target buffer
-    int max_virt_lines = 0;
-    for (diff_T *dp = thistopdiff; dp != NULL; dp = dp->df_next)
-    {
-	if (dp->df_lnum[toidx] + dp->df_count[toidx] <= curlinenum_to)
-	    max_virt_lines += get_max_diff_length(dp);
-	else
-	{
-	    if (dp->df_lnum[toidx] <= curlinenum_to)
-		max_virt_lines += curlinenum_to - dp->df_lnum[toidx];
-	    break;
-	}
-    }
-
-    if (diff_flags & DIFF_FILLER)
-	// should always be non-negative as max_virt_lines is larger
-	(*topfill) = max_virt_lines - virtual_lines_passed;
-    (*topline) = curlinenum_to;
-}
-
-// Apply results from the linematch algorithm and apply to 'dp' by splitting it
-// into multiple adjacent diff blocks.
-    static void
-apply_linematch_results(
-    diff_T	*dp,
-    size_t	decisions_length,
-    const int	*decisions)
-{
-    // get the start line number here in each diff buffer, and then increment
-    int		line_numbers[DB_COUNT];
-    int		outputmap[DB_COUNT];
-    size_t	ndiffs = 0;
-
-    for (int i = 0; i < DB_COUNT; i++)
-    {
-	if (curtab->tp_diffbuf[i] != NULL)
-	{
-	    line_numbers[i] = dp->df_lnum[i];
-	    dp->df_count[i] = 0;
-
-	    // Keep track of the index of the diff buffer we are using here.
-	    // We will use this to write the output of the algorithm to
-	    // diff_T structs at the correct indexes
-	    outputmap[ndiffs] = i;
-	    ndiffs++;
-	}
-    }
-
-    // write the diffs starting with the current diff block
-    diff_T *dp_s = dp;
-    for (size_t i = 0; i < decisions_length; i++)
-    {
-	// Don't allocate on first iter since we can reuse the initial
-	// diffblock
-	if (i != 0 && (decisions[i - 1] != decisions[i]))
-	{
-	    // create new sub diff blocks to segment the original diff block
-	    // which we further divided by running the linematch algorithm
-	    dp_s = diff_alloc_new(curtab, dp_s, dp_s->df_next);
-	    dp_s->is_linematched = TRUE;
-	    for (int j = 0; j < DB_COUNT; j++)
-	    {
-		if (curtab->tp_diffbuf[j] != NULL)
-		{
-		    dp_s->df_lnum[j] = line_numbers[j];
-		    dp_s->df_count[j] = 0;
-		}
-	    }
-	}
-	for (size_t j = 0; j < ndiffs; j++)
-	{
-	    if (decisions[i] & (1 << j))
-	    {
-		// will need to use the map here
-		dp_s->df_count[outputmap[j]]++;
-		line_numbers[outputmap[j]]++;
-	    }
-	}
-    }
-    dp->is_linematched = TRUE;
-}
-
-    static void
-run_linematch_algorithm(diff_T *dp)
-{
-    // define buffers for diff algorithm
-    diffin_T		diffbufs_mm[DB_COUNT];
-    const mmfile_t	*diffbufs[DB_COUNT];
-    int			diff_length[DB_COUNT];
-    size_t		ndiffs = 0;
-
-    for (int i = 0; i < DB_COUNT; i++)
-    {
-	if (curtab->tp_diffbuf[i] != NULL)
-	{
-	    // write the contents of the entire buffer to
-	    // diffbufs_mm[diffbuffers_count]
-	    if (dp->df_count[i] > 0)
-	    {
-		diff_write_buffer(curtab->tp_diffbuf[i], &diffbufs_mm[ndiffs],
-			dp->df_lnum[i], dp->df_lnum[i] + dp->df_count[i] - 1);
-	    }
-	    else
-	    {
-		diffbufs_mm[ndiffs].din_mmfile.size = 0;
-		diffbufs_mm[ndiffs].din_mmfile.ptr = NULL;
-	    }
-
-	    diffbufs[ndiffs] = &diffbufs_mm[ndiffs].din_mmfile;
-
-	    // keep track of the length of this diff block to pass it to the
-	    // linematch algorithm
-	    diff_length[ndiffs] = dp->df_count[i];
-
-	    // increment the amount of diff buffers we are passing to the
-	    // algorithm
-	    ndiffs++;
-	}
-    }
-
-    // we will get the output of the linematch algorithm in the format of an
-    // array of integers (*decisions) and the length of that array
-    // (decisions_length)
-    int *decisions = NULL;
-    const int iwhite = (diff_flags & (DIFF_IWHITEALL | DIFF_IWHITE)) > 0 ? 1 : 0;
-    size_t decisions_length =
-	linematch_nbuffers(diffbufs, diff_length, ndiffs, &decisions, iwhite);
-
-    for (size_t i = 0; i < ndiffs; i++)
-	free(diffbufs_mm[i].din_mmfile.ptr); // TODO should this be mnv_free ?
-
-    apply_linematch_results(dp, decisions_length, decisions);
-
-    free(decisions);
-}
-
-/*
- * Check diff status for line "lnum" in buffer "buf":
- * Returns > 0 for inserting that many filler lines above it (never happens
- * when 'diffopt' doesn't contain "filler"). Otherwise returns 0.
- *
- * "linestatus" (can be NULL) will be set to:
- * 0 for nothing special.
- * -1 for a line that should be highlighted as changed.
- * -2 for a line that should be highlighted as added/deleted.
- *
- * This should only be used for windows where 'diff' is set.
- *
- * Note that it's possible for a changed/added/deleted line to also have filler
- * lines above it. This happens when using linematch or using diff anchors (at
- * the anchored lines).
- */
-    int
-diff_check_with_linestatus(win_T *wp, linenr_T lnum, int *linestatus)
-{
-    int		idx;		// index in tp_diffbuf[] for this buffer
-    diff_T	*dp;
-    int		maxcount;
-    int		i;
-    buf_T	*buf = wp->w_buffer;
-    int		cmp;
-
-    if (linestatus != NULL)
-	*linestatus = 0;
-
-    if (curtab->tp_diff_invalid)
-	ex_diffupdate(NULL);		// update after a big change
-
-    if (curtab->tp_first_diff == NULL || !wp->w_p_diff)	// no diffs at all
-	return 0;
-
-    // safety check: "lnum" must be a buffer line
-    if (lnum < 1 || lnum > buf->b_ml.ml_line_count + 1)
-	return 0;
-
-    idx = diff_buf_idx(buf);
-    if (idx == DB_COUNT)
-	return 0;		// no diffs for buffer "buf"
-
-# ifdef FEAT_FOLDING
-    // A closed fold never has filler lines.
-    if (hasFoldingWin(wp, lnum, NULL, NULL, TRUE, NULL))
-	return 0;
-# endif
-
-    // search for a change that includes "lnum" in the list of diffblocks.
-    FOR_ALL_DIFFBLOCKS_IN_TAB(curtab, dp)
-	if (lnum <= dp->df_lnum[idx] + dp->df_count[idx])
-	    break;
-    if (dp == NULL || lnum < dp->df_lnum[idx])
-	return 0;
-
-    // Don't run linematch when lnum is offscreen.  Useful for scrollbind
-    // calculations which need to count all the filler lines above the screen.
-    if (lnum >= wp->w_topline && lnum < wp->w_botline
-				&& !dp->is_linematched && diff_linematch(dp)
-				&& diff_check_sanity(curtab, dp))
-	run_linematch_algorithm(dp);
-
-    // Insert filler lines above the line just below the change.  Will return 0
-    // when this buf had the max count.
-    int num_fill = 0;
-    while (lnum == dp->df_lnum[idx] + dp->df_count[idx])
-    {
-	// Only calculate fill lines if 'diffopt' contains "filler". Otherwise
-	// returns 0 filler lines.
-	if (diff_flags & DIFF_FILLER)
-	{
-	    maxcount = get_max_diff_length(dp);
-	    num_fill += maxcount - dp->df_count[idx];
-	}
-
-	// If there are adjacent blocks (e.g. linematch or anchor), loop
-	// through them. It's possible for multiple adjacent blocks to
-	// contribute to filler lines.
-	// This also helps us find the last diff block in the list of adjacent
-	// blocks which is necessary when it is a change/inserted line right
-	// after added lines.
-	if (dp->df_next != NULL
-		&& lnum >= dp->df_next->df_lnum[idx]
-		&& lnum <= dp->df_next->df_lnum[idx] + dp->df_next->df_count[idx])
-	    dp = dp->df_next;
-	else
-	    break;
-    }
-
-    if (lnum < dp->df_lnum[idx] + dp->df_count[idx])
-    {
-	int	zero = FALSE;
-
-	// Changed or inserted line.  If the other buffers have a count of
-	// zero, the lines were inserted.  If the other buffers have the same
-	// count, check if the lines are identical.
-	cmp = FALSE;
-	for (i = 0; i < DB_COUNT; ++i)
-	    if (i != idx && curtab->tp_diffbuf[i] != NULL)
-	    {
-		if (dp->df_count[i] == 0)
-		    zero = TRUE;
-		else
-		{
-		    if (dp->df_count[i] != dp->df_count[idx])
-		    {
-			if (linestatus)
-			    *linestatus = -1;	// nr of lines changed.
-			return num_fill;
-		    }
-		    cmp = TRUE;
-		}
-	    }
-	if (cmp)
-	{
-	    // Compare all lines.  If they are equal the lines were inserted
-	    // in some buffers, deleted in others, but not changed.
-	    for (i = 0; i < DB_COUNT; ++i)
-		if (i != idx && curtab->tp_diffbuf[i] != NULL
-						      && dp->df_count[i] != 0)
-		    if (!diff_equal_entry(dp, idx, i))
-		    {
-			if (linestatus)
-			    *linestatus = -1;
-			return num_fill;
-		    }
-	}
-	// If there is no buffer with zero lines then there is no difference
-	// any longer.  Happens when making a change (or undo) that removes
-	// the difference.  Can't remove the entry here, we might be halfway
-	// updating the window.  Just report the text as unchanged.  Other
-	// windows might still show the change though.
-	if (zero == FALSE)
-	    return num_fill;
-	if (linestatus)
-	    *linestatus = -2;
-	return num_fill;
-    }
-    return num_fill;
-}
-
-/*
- * Compare two entries in diff "*dp" and return TRUE if they are equal.
- */
-    static int
-diff_equal_entry(diff_T *dp, int idx1, int idx2)
-{
-    int		i;
-    char_u	*line;
-    int		cmp;
-
-    if (dp->df_count[idx1] != dp->df_count[idx2])
-	return FALSE;
-    if (diff_check_sanity(curtab, dp) == FAIL)
-	return FALSE;
-    for (i = 0; i < dp->df_count[idx1]; ++i)
-    {
-	line = mnv_strsave(ml_get_buf(curtab->tp_diffbuf[idx1],
-					       dp->df_lnum[idx1] + i, FALSE));
-	if (line == NULL)
-	    return FALSE;
-	cmp = diff_cmp(line, ml_get_buf(curtab->tp_diffbuf[idx2],
-					       dp->df_lnum[idx2] + i, FALSE));
-	mnv_free(line);
-	if (cmp != 0)
-	    return FALSE;
-    }
-    return TRUE;
-}
-
-/*
- * Compare the characters at "p1" and "p2".  If they are equal (possibly
- * ignoring case) return TRUE and set "len" to the number of bytes.
- */
-    static int
-diff_equal_char(char_u *p1, char_u *p2, int *len)
-{
-    int l  = (*mb_ptr2len)(p1);
-
-    if (l != (*mb_ptr2len)(p2))
-	return FALSE;
-    if (l > 1)
-    {
-	if (STRNCMP(p1, p2, l) != 0
-		&& (!enc_utf8
-		    || !(diff_flags & DIFF_ICASE)
-		    || utf_fold(utf_ptr2char(p1))
-						!= utf_fold(utf_ptr2char(p2))))
-	    return FALSE;
-	*len = l;
-    }
-    else
-    {
-	if ((*p1 != *p2)
-		&& (!(diff_flags & DIFF_ICASE)
-		    || TOLOWER_LOC(*p1) != TOLOWER_LOC(*p2)))
-	    return FALSE;
-	*len = 1;
-    }
-    return TRUE;
-}
-
-/*
- * Compare strings "s1" and "s2" according to 'diffopt'.
- * Return non-zero when they are different.
- */
-    static int
-diff_cmp(char_u *s1, char_u *s2)
-{
-    char_u	*p1, *p2;
-    int		l;
-
-    if ((diff_flags & DIFF_IBLANK)
-	    && (*skipwhite(s1) == NUL || *skipwhite(s2) == NUL))
-	return 0;
-
-    if ((diff_flags & (DIFF_ICASE | ALL_WHITE_DIFF)) == 0)
-	return STRCMP(s1, s2);
-    if ((diff_flags & DIFF_ICASE) && !(diff_flags & ALL_WHITE_DIFF))
-	return MB_STRICMP(s1, s2);
-
-    p1 = s1;
-    p2 = s2;
-
-    // Ignore white space changes and possibly ignore case.
-    while (*p1 != NUL && *p2 != NUL)
-    {
-	if (((diff_flags & DIFF_IWHITE)
-		    && MNV_ISWHITE(*p1) && MNV_ISWHITE(*p2))
-		|| ((diff_flags & DIFF_IWHITEALL)
-		    && (MNV_ISWHITE(*p1) || MNV_ISWHITE(*p2))))
-	{
-	    p1 = skipwhite(p1);
-	    p2 = skipwhite(p2);
-	}
-	else
-	{
-	    if (!diff_equal_char(p1, p2, &l))
-		break;
-	    p1 += l;
-	    p2 += l;
-	}
-    }
-
-    // Ignore trailing white space.
-    p1 = skipwhite(p1);
-    p2 = skipwhite(p2);
-    if (*p1 != NUL || *p2 != NUL)
-	return 1;
-    return 0;
-}
-
-/*
- * Return the number of filler lines above "lnum".
- */
-    int
-diff_check_fill(win_T *wp, linenr_T lnum)
-{
-    int		n;
-
-    // be quick when there are no filler lines
-    if (!(diff_flags & DIFF_FILLER))
-	return 0;
-    n = diff_check_with_linestatus(wp, lnum, NULL);
-    if (n <= 0)
-	return 0;
-    return n;
-}
-
-/*
- * Set the topline of "towin" to match the position in "fromwin", so that they
- * show the same diff'ed lines.
- */
-    void
-diff_set_topline(win_T *fromwin, win_T *towin)
-{
-    buf_T	*frombuf = fromwin->w_buffer;
-    linenr_T	lnum;
-    int		fromidx;
-    int		toidx;
-    diff_T	*dp;
-
-    fromidx = diff_buf_idx(frombuf);
-    if (fromidx == DB_COUNT)
-	return;		// safety check
-
-    if (curtab->tp_diff_invalid)
-	ex_diffupdate(NULL);		// update after a big change
-
-    lnum = fromwin->w_topline;
-    towin->w_topfill = 0;
-
-    // search for a change that includes "lnum" in the list of diffblocks.
-    FOR_ALL_DIFFBLOCKS_IN_TAB(curtab, dp)
-	if (lnum <= dp->df_lnum[fromidx] + dp->df_count[fromidx])
-	    break;
-    if (dp == NULL)
-    {
-	// After last change, compute topline relative to end of file; no
-	// filler lines.
-	towin->w_topline = towin->w_buffer->b_ml.ml_line_count
-				       - (frombuf->b_ml.ml_line_count - lnum);
-    }
-    else
-    {
-	// Find index for "towin".
-	toidx = diff_buf_idx(towin->w_buffer);
-	if (toidx == DB_COUNT)
-	    return;		// safety check
-
-	towin->w_topline = lnum + (dp->df_lnum[toidx] - dp->df_lnum[fromidx]);
-	if (lnum >= dp->df_lnum[fromidx])
-	{
-	    calculate_topfill_and_topline(fromidx, toidx,
-					    fromwin->w_topline,
-					    fromwin->w_topfill,
-					    &towin->w_topfill,
-					    &towin->w_topline);
-	}
-    }
-
-    // safety check (if diff info gets outdated strange things may happen)
-    towin->w_botfill = FALSE;
-    if (towin->w_topline > towin->w_buffer->b_ml.ml_line_count)
-    {
-	towin->w_topline = towin->w_buffer->b_ml.ml_line_count;
-	towin->w_botfill = TRUE;
-    }
-    if (towin->w_topline < 1)
-    {
-	towin->w_topline = 1;
-	towin->w_topfill = 0;
-    }
-
-    // When w_topline changes need to recompute w_botline and cursor position
-    invalidate_botline_win(towin);
-    changed_line_abv_curs_win(towin);
-
-    check_topfill(towin, FALSE);
-# ifdef FEAT_FOLDING
-    (void)hasFoldingWin(towin, towin->w_topline, &towin->w_topline,
-							    NULL, TRUE, NULL);
-# endif
-}
-
-/*
- * Parse the diff anchors. If "check_only" is set, will only make sure the
- * syntax is correct.
- */
-    static int
-parse_diffanchors(
-    int		check_only,
-    buf_T	*buf,
-    linenr_T	*anchors,
-    int		*num_anchors)
-{
-    int i;
-    char_u *dia = (*buf->b_p_dia == NUL) ? p_dia : buf->b_p_dia;
-
-    buf_T *orig_curbuf = curbuf;
-    win_T *orig_curwin = curwin;
-
-    win_T *bufwin = NULL;
-    if (check_only)
-	bufwin = curwin;
-    else
-    {
-	// Find the first window tied to this buffer and ignore the rest. Will
-	// only matter for window-specific addresses like `.` or `''`.
-	FOR_ALL_WINDOWS(bufwin)
-	    if (bufwin->w_buffer == buf && bufwin->w_p_diff)
-		break;
-	if (bufwin == NULL && *dia != NUL)
-	{
-	    // The buffer is hidden. Currently this is not supported due to the
-	    // edge cases of needing to decide if an address is window-specific
-	    // or not. We could add more checks in the future so we can detect
-	    // whether an address relies on curwin to make this more fleixble.
-	    emsg(_(e_diff_anchors_with_hidden_windows));
-	    return FAIL;
-	}
-    }
-
-    for (i = 0; i < MAX_DIFF_ANCHORS && *dia != NUL; i++)
-    {
-	if (*dia == ',') // don't allow empty values
-	    return FAIL;
-
-	curbuf = buf;
-	curwin = bufwin;
-	linenr_T lnum = get_address(NULL, &dia, ADDR_LINES, check_only, TRUE, FALSE, 1);
-	curbuf = orig_curbuf;
-	curwin = orig_curwin;
-
-	if (dia == NULL) // error detected
-	    return FAIL;
-	if (*dia != ',' && *dia != NUL)
-	    return FAIL;
-
-	if (!check_only
-		&& (lnum == MAXLNUM || lnum <= 0 || lnum > buf->b_ml.ml_line_count + 1))
-	{
-	    emsg(_(e_invalid_range));
-	    return FAIL;
-	}
-
-	if (anchors != NULL)
-	    anchors[i] = lnum;
-
-	if (*dia == ',')
-	    dia++;
-    }
-    if (i == MAX_DIFF_ANCHORS && *dia != NUL)
-    {
-	semsg(_(e_cannot_have_more_than_nr_diff_anchors), MAX_DIFF_ANCHORS);
-	return FAIL;
-    }
-    if (num_anchors != NULL)
-	*num_anchors = i;
-    return OK;
-}
-
-/*
- * This is called when 'diffanchors' is changed.
- */
-    int
-diffanchors_changed(int buflocal)
-{
-    int result = parse_diffanchors(TRUE, curbuf, NULL, NULL);
-    if (result == OK && (diff_flags & DIFF_ANCHOR))
-    {
-	tabpage_T	*tp;
-	FOR_ALL_TABPAGES(tp)
-	{
-	    if (!buflocal)
-		tp->tp_diff_invalid = TRUE;
-	    else
-	    {
-		for (int idx = 0; idx < DB_COUNT; ++idx)
-		    if (tp->tp_diffbuf[idx] == curbuf)
-		    {
-			tp->tp_diff_invalid = TRUE;
-			break;
-		    }
-	    }
-	}
-    }
-    return result;
-}
-
-/*
- * This is called when 'diffopt' is changed.
- */
-    int
-diffopt_changed(void)
-{
-    char_u	*p;
-    int		diff_context_new = 6;
-    int		linematch_lines_new = 0;
-    int		diff_flags_new = 0;
-    int		diff_foldcolumn_new = 2;
-    long	diff_algorithm_new = 0;
-    long	diff_indent_heuristic = 0;
-    tabpage_T	*tp;
-
-    p = p_dip;
-    while (*p != NUL)
-    {
-	// Note: Keep this in sync with p_dip_values
-	if (STRNCMP(p, "filler", 6) == 0)
-	{
-	    p += 6;
-	    diff_flags_new |= DIFF_FILLER;
-	}
-	else if (STRNCMP(p, "anchor", 6) == 0)
-	{
-	    p += 6;
-	    diff_flags_new |= DIFF_ANCHOR;
-	}
-	else if (STRNCMP(p, "context:", 8) == 0 && MNV_ISDIGIT(p[8]))
-	{
-	    p += 8;
-	    diff_context_new = getdigits(&p);
-	}
-	else if (STRNCMP(p, "iblank", 6) == 0)
-	{
-	    p += 6;
-	    diff_flags_new |= DIFF_IBLANK;
-	}
-	else if (STRNCMP(p, "icase", 5) == 0)
-	{
-	    p += 5;
-	    diff_flags_new |= DIFF_ICASE;
-	}
-	else if (STRNCMP(p, "iwhiteall", 9) == 0)
-	{
-	    p += 9;
-	    diff_flags_new |= DIFF_IWHITEALL;
-	}
-	else if (STRNCMP(p, "iwhiteeol", 9) == 0)
-	{
-	    p += 9;
-	    diff_flags_new |= DIFF_IWHITEEOL;
-	}
-	else if (STRNCMP(p, "iwhite", 6) == 0)
-	{
-	    p += 6;
-	    diff_flags_new |= DIFF_IWHITE;
-	}
-	else if (STRNCMP(p, "horizontal", 10) == 0)
-	{
-	    p += 10;
-	    diff_flags_new |= DIFF_HORIZONTAL;
-	}
-	else if (STRNCMP(p, "vertical", 8) == 0)
-	{
-	    p += 8;
-	    diff_flags_new |= DIFF_VERTICAL;
-	}
-	else if (STRNCMP(p, "foldcolumn:", 11) == 0 && MNV_ISDIGIT(p[11]))
-	{
-	    p += 11;
-	    diff_foldcolumn_new = getdigits(&p);
-	}
-	else if (STRNCMP(p, "hiddenoff", 9) == 0)
-	{
-	    p += 9;
-	    diff_flags_new |= DIFF_HIDDEN_OFF;
-	}
-	else if (STRNCMP(p, "closeoff", 8) == 0)
-	{
-	    p += 8;
-	    diff_flags_new |= DIFF_CLOSE_OFF;
-	}
-	else if (STRNCMP(p, "followwrap", 10) == 0)
-	{
-	    p += 10;
-	    diff_flags_new |= DIFF_FOLLOWWRAP;
-	}
-	else if (STRNCMP(p, "indent-heuristic", 16) == 0)
-	{
-	    p += 16;
-	    diff_indent_heuristic = XDF_INDENT_HEURISTIC;
-	}
-	else if (STRNCMP(p, "internal", 8) == 0)
-	{
-	    p += 8;
-	    diff_flags_new |= DIFF_INTERNAL;
-	}
-	else if (STRNCMP(p, "algorithm:", 10) == 0)
-	{
-	    // Note: Keep this in sync with p_dip_algorithm_values.
-	    p += 10;
-	    if (STRNCMP(p, "myers", 5) == 0)
-	    {
-		p += 5;
-		diff_algorithm_new = 0;
-	    }
-	    else if (STRNCMP(p, "minimal", 7) == 0)
-	    {
-		p += 7;
-		diff_algorithm_new = XDF_NEED_MINIMAL;
-	    }
-	    else if (STRNCMP(p, "patience", 8) == 0)
-	    {
-		p += 8;
-		diff_algorithm_new = XDF_PATIENCE_DIFF;
-	    }
-	    else if (STRNCMP(p, "histogram", 9) == 0)
-	    {
-		p += 9;
-		diff_algorithm_new = XDF_HISTOGRAM_DIFF;
-	    }
-	    else
-		return FAIL;
-	}
-	else if (STRNCMP(p, "inline:", 7) == 0)
-	{
-	    // Note: Keep this in sync with p_dip_inline_values.
-	    p += 7;
-	    if (STRNCMP(p, "none", 4) == 0)
-	    {
-		p += 4;
-		diff_flags_new &= ~(ALL_INLINE);
-		diff_flags_new |= DIFF_INLINE_NONE;
-	    }
-	    else if (STRNCMP(p, "simple", 6) == 0)
-	    {
-		p += 6;
-		diff_flags_new &= ~(ALL_INLINE);
-		diff_flags_new |= DIFF_INLINE_SIMPLE;
-	    }
-	    else if (STRNCMP(p, "char", 4) == 0)
-	    {
-		p += 4;
-		diff_flags_new &= ~(ALL_INLINE);
-		diff_flags_new |= DIFF_INLINE_CHAR;
-	    }
-	    else if (STRNCMP(p, "word", 4) == 0)
-	    {
-		p += 4;
-		diff_flags_new &= ~(ALL_INLINE);
-		diff_flags_new |= DIFF_INLINE_WORD;
-	    }
-	    else
-		return FAIL;
-	}
-	else if (STRNCMP(p, "linematch:", 10) == 0 && MNV_ISDIGIT(p[10]))
-	{
-	    p += 10;
-	    linematch_lines_new = getdigits(&p);
-	    diff_flags_new |= DIFF_LINEMATCH;
-
-	    // linematch does not make sense without filler set
-	    diff_flags_new |= DIFF_FILLER;
-	}
-
-	if (*p != ',' && *p != NUL)
-	    return FAIL;
-	if (*p == ',')
-	    ++p;
-    }
-
-    diff_algorithm_new |= diff_indent_heuristic;
-
-    // Can't have both "horizontal" and "vertical".
-    if ((diff_flags_new & DIFF_HORIZONTAL) && (diff_flags_new & DIFF_VERTICAL))
-	return FAIL;
-
-    // If flags were added or removed, or the algorithm was changed, need to
-    // update the diff.
-    if (diff_flags != diff_flags_new || diff_algorithm != diff_algorithm_new)
-	FOR_ALL_TABPAGES(tp)
-	    tp->tp_diff_invalid = TRUE;
-
-    diff_flags = diff_flags_new;
-    diff_context = diff_context_new == 0 ? 1 : diff_context_new;
-    linematch_lines = linematch_lines_new;
-    diff_foldcolumn = diff_foldcolumn_new;
-    diff_algorithm = diff_algorithm_new;
-
-    diff_redraw(TRUE);
-
-    // recompute the scroll binding with the new option value, may
-    // remove or add filler lines
-    check_scrollbind((linenr_T)0, 0L);
-
-    return OK;
-}
-
-/*
- * Return TRUE if 'diffopt' contains "horizontal".
- */
-    int
-diffopt_horizontal(void)
-{
-    return (diff_flags & DIFF_HORIZONTAL) != 0;
-}
-
-/*
- * Return TRUE if 'diffopt' contains "hiddenoff".
- */
-    int
-diffopt_hiddenoff(void)
-{
-    return (diff_flags & DIFF_HIDDEN_OFF) != 0;
-}
-
-/*
- * Return TRUE if 'diffopt' contains "closeoff".
- */
-    int
-diffopt_closeoff(void)
-{
-    return (diff_flags & DIFF_CLOSE_OFF) != 0;
-}
-
-/*
- * Called when a line has been updated. Used for updating inline diff in Insert
- * mode without waiting for global diff update later.
- */
-    void
-diff_update_line(linenr_T lnum)
-{
-    int		idx;
-    diff_T	*dp;
-
-    if (!(diff_flags & ALL_INLINE_DIFF))
-	// We only care if we are doing inline-diff where we cache the diff results
-	return;
-
-    idx = diff_buf_idx(curbuf);
-    if (idx == DB_COUNT)
-	return;
-    FOR_ALL_DIFFBLOCKS_IN_TAB(curtab, dp)
-	if (lnum <= dp->df_lnum[idx] + dp->df_count[idx])
-	    break;
-
-    // clear the inline change cache as it's invalid
-    if (dp != NULL)
-    {
-	dp->has_changes = FALSE;
-	dp->df_changes.ga_len = 0;
-    }
-}
-
-static diffline_change_T simple_diffline_change; // used for simple inline diff algorithm
-
-/*
- * Parse a diffline struct and returns the [start,end] byte offsets
- *
- * Returns TRUE if this change was added, no other buffer has it.
- */
-    int
-diff_change_parse(
-    diffline_T *diffline,
-    diffline_change_T *change,
-    int *change_start,
-    int *change_end)
-{
-    if (change->dc_start_lnum_off[diffline->bufidx] < diffline->lineoff)
-	*change_start = 0;
-    else
-	*change_start = change->dc_start[diffline->bufidx];
-    if (change->dc_end_lnum_off[diffline->bufidx] > diffline->lineoff)
-	*change_end = INT_MAX;
-    else
-	*change_end = change->dc_end[diffline->bufidx];
-
-    if (change == &simple_diffline_change)
-    {
-	// This is what we returned from simple inline diff. We always consider
-	// the range to be changed, rather than added for now.
-	return FALSE;
-    }
-
-    // Find out whether this is an addition. Note that for multi buffer diff,
-    // to tell whether lines are additions we check whether all the other diff
-    // lines are identical (in diff_check_with_linestatus). If so, we mark them
-    // as add. We don't do that for inline diff here for simplicity.
-    for (int i = 0; i < DB_COUNT; i++)
-    {
-	if (i == diffline->bufidx)
-	    continue;
-	if (change->dc_start[i] != change->dc_end[i]
-		|| change->dc_end_lnum_off[i] != change->dc_start_lnum_off[i])
-	{
-	    return FALSE;
-	}
-    }
-    return TRUE;
-}
-
-/*
- * Find the difference within a changed line and returns [startp,endp] byte
- * positions.  Performs a simple algorithm by finding a single range in the
- * middle.
- *
- * If diffopt has DIFF_INLINE_NONE set, then this will only calculate the return
- * value (added or changed), but startp/endp will not be calculated.
- *
- * Returns TRUE if the line was added, no other buffer has it.
- */
-    static int
-diff_find_change_simple(
-    win_T	*wp,
-    linenr_T	lnum,
-    diff_T	*dp,
-    int		idx,
-    int		*startp,	// first char of the change
-    int		*endp)		// last char of the change
-{
-    char_u	*line_org;
-    char_u	*line_new;
-    int		i;
-    int		si_org, si_new;
-    int		ei_org, ei_new;
-    int		off;
-    int		added = TRUE;
-    char_u	*p1, *p2;
-    int		l;
-
-    if (diff_flags & DIFF_INLINE_NONE)
-    {
-	// We only care about the return value, not the actual string comparisons.
-	line_org = NULL;
-    }
-    else
-    {
-	// Make a copy of the line, the next ml_get() will invalidate it.
-	line_org = mnv_strsave(ml_get_buf(wp->w_buffer, lnum, FALSE));
-	if (line_org == NULL)
-	    return FALSE;
-    }
-
-    off = lnum - dp->df_lnum[idx];
-
-    for (i = 0; i < DB_COUNT; ++i)
-	if (curtab->tp_diffbuf[i] != NULL && i != idx)
-	{
-	    // Skip lines that are not in the other change (filler lines).
-	    if (off >= dp->df_count[i])
-		continue;
-	    added = FALSE;
-	    if (diff_flags & DIFF_INLINE_NONE)
-		break; // early terminate as we only care about the return value
-
-	    line_new = ml_get_buf(curtab->tp_diffbuf[i],
-						 dp->df_lnum[i] + off, FALSE);
-
-	    // Search for start of difference
-	    si_org = si_new = 0;
-	    while (line_org[si_org] != NUL)
-	    {
-		if (((diff_flags & DIFF_IWHITE)
-			    && MNV_ISWHITE(line_org[si_org])
-					      && MNV_ISWHITE(line_new[si_new]))
-			|| ((diff_flags & DIFF_IWHITEALL)
-			    && (MNV_ISWHITE(line_org[si_org])
-					    || MNV_ISWHITE(line_new[si_new]))))
-		{
-		    si_org = (int)(skipwhite(line_org + si_org) - line_org);
-		    si_new = (int)(skipwhite(line_new + si_new) - line_new);
-		}
-		else
-		{
-		    if (!diff_equal_char(line_org + si_org, line_new + si_new,
-									   &l))
-			break;
-		    si_org += l;
-		    si_new += l;
-		}
-	    }
-	    if (has_mbyte)
-	    {
-		// Move back to first byte of character in both lines (may
-		// have "nn^" in line_org and "n^ in line_new).
-		si_org -= (*mb_head_off)(line_org, line_org + si_org);
-		si_new -= (*mb_head_off)(line_new, line_new + si_new);
-	    }
-	    if (*startp > si_org)
-		*startp = si_org;
-
-	    // Search for end of difference, if any.
-	    if (line_org[si_org] != NUL || line_new[si_new] != NUL)
-	    {
-		ei_org = (int)STRLEN(line_org);
-		ei_new = (int)STRLEN(line_new);
-		while (ei_org >= *startp && ei_new >= si_new
-						&& ei_org >= 0 && ei_new >= 0)
-		{
-		    if (((diff_flags & DIFF_IWHITE)
-				&& MNV_ISWHITE(line_org[ei_org])
-					      && MNV_ISWHITE(line_new[ei_new]))
-			    || ((diff_flags & DIFF_IWHITEALL)
-				&& (MNV_ISWHITE(line_org[ei_org])
-					    || MNV_ISWHITE(line_new[ei_new]))))
-		    {
-			while (ei_org >= *startp
-					     && MNV_ISWHITE(line_org[ei_org]))
-			    --ei_org;
-			while (ei_new >= si_new
-					     && MNV_ISWHITE(line_new[ei_new]))
-			    --ei_new;
-		    }
-		    else
-		    {
-			p1 = line_org + ei_org;
-			p2 = line_new + ei_new;
-			p1 -= (*mb_head_off)(line_org, p1);
-			p2 -= (*mb_head_off)(line_new, p2);
-			if (!diff_equal_char(p1, p2, &l))
-			    break;
-			ei_org -= l;
-			ei_new -= l;
-		    }
-		}
-		if (*endp < ei_org)
-		    *endp = ei_org;
-	    }
-	}
-
-    mnv_free(line_org);
-    return added;
-}
-
-/*
- * Mapping used for mapping from temporary mmfile created for inline diff back
- * to original buffer's line/col.
- */
-typedef struct
-{
-    long byte_start;
-    long num_bytes;
-    int lineoff;
-} linemap_entry_T;
-
-/*
- * Refine inline character-wise diff blocks to create a more human readable
- * highlight. Otherwise a naive diff under existing algorithms tends to create
- * a messy output with lots of small gaps.
- * It does this by merging adjacent long diff blocks if they are only separated
- * by a couple characters.
- * These are done by heuristics and can be further tuned.
- */
-    static void
-diff_refine_inline_char_highlight(diff_T *dp_orig, garray_T *linemap, int idx1)
-{
-    // Perform multiple passes so that newly merged blocks will now be long
-    // enough which may cause other previously unmerged gaps to be merged as
-    // well.
-    int pass = 1;
-    do
-    {
-	int has_unmerged_gaps = FALSE;
-	int has_merged_gaps = FALSE;
-	diff_T *dp = dp_orig;
-	while (dp!= NULL && dp->df_next != NULL)
-	{
-	    // Only use first buffer to calculate the gap because the gap is
-	    // unchanged text, which would be the same in all buffers.
-	    if (dp->df_lnum[idx1] + dp->df_count[idx1] - 1 >= linemap[idx1].ga_len
-		    || dp->df_next->df_lnum[idx1] - 1 >= linemap[idx1].ga_len)
-	    {
-		dp = dp->df_next;
-		continue;
-	    }
-
-	    // If the gap occurs over different lines, don't consider it
-	    linemap_entry_T *entry1 = &((linemap_entry_T*)linemap[idx1].ga_data)[dp->df_lnum[idx1] + dp->df_count[idx1] - 1];
-	    linemap_entry_T *entry2 = &((linemap_entry_T*)linemap[idx1].ga_data)[dp->df_next->df_lnum[idx1] - 1];
-	    if (entry1->lineoff != entry2->lineoff)
-	    {
-		dp = dp->df_next;
-		continue;
-	    }
-
-	    linenr_T gap = dp->df_next->df_lnum[idx1] - (dp->df_lnum[idx1] + dp->df_count[idx1]);
-	    if (gap <= 3)
-	    {
-		linenr_T max_df_count = 0;
-		for (int i = 0; i < DB_COUNT; i++)
-		    max_df_count = MAX(max_df_count, dp->df_count[i] + dp->df_next->df_count[i]);
-
-		if (max_df_count >= gap * 4)
-		{
-		    // Merge current block with the next one. Don't advance the
-		    // pointer so we try the same merged block against the next
-		    // one.
-		    for (int i = 0; i < DB_COUNT; i++)
-		    {
-			dp->df_count[i] = dp->df_next->df_lnum[i]
-			    + dp->df_next->df_count[i] - dp->df_lnum[i];
-		    }
-		    diff_T *dp_next = dp->df_next;
-		    dp->df_next = dp_next->df_next;
-		    clear_diffblock(dp_next);
-		    has_merged_gaps = TRUE;
-		    continue;
-		}
-		else
-		    has_unmerged_gaps = TRUE;
-	    }
-	    dp = dp->df_next;
-	}
-	if (!has_unmerged_gaps || !has_merged_gaps)
-	    break;
-    } while (pass++ < 4); // use limited number of passes to avoid excessive looping
-}
-
-/*
- * Refine inline word diff blocks by merging blocks that are only separated
- * by whitespace or punctuation. This creates more coherent highlighting.
- */
-    static void
-diff_refine_inline_word_highlight(diff_T *dp_orig, garray_T *linemap, int idx1,
-				  linenr_T start_lnum)
-{
-    int pass = 1;
-    do
-    {
-	diff_T *dp = dp_orig;
-
-	while (dp != NULL && dp->df_next != NULL)
-	{
-	    // Only merge blocks on the same line
-	    if (dp->df_lnum[idx1] + dp->df_count[idx1] - 1 >= linemap[idx1]. ga_len
-		    || dp->df_next->df_lnum[idx1] - 1 >= linemap[idx1]. ga_len)
-	    {
-		dp = dp->df_next;
-		continue;
-	    }
-
-	    linemap_entry_T *entry1 =
-		&((linemap_entry_T *)linemap[idx1].ga_data)[dp->df_lnum[idx1] + dp->df_count[idx1] - 2];
-	    linemap_entry_T *entry2 =
-		&((linemap_entry_T *)linemap[idx1].ga_data)[dp->df_next->df_lnum[idx1] - 1];
-
-	    // Skip if blocks are on different lines
-	    if (entry1->lineoff != entry2->lineoff)
-	    {
-		dp = dp->df_next;
-		continue;
-	    }
-
-	    // Calculate the gap between blocks
-	    int gap_start = entry1->byte_start + entry1->num_bytes;
-	    int gap_end = entry2->byte_start;
-	    int gap_size = gap_end - gap_start;
-
-	    // Merge adjacent diff blocks separated by small gaps to reduce visual
-	    // fragmentation. Gap threshold is set to 5 bytes which handles most
-	    // common separators (spaces, punctuation, short variable names) while
-	    // still preserving visually distinct changes.
-	    if (gap_size <= 0 || gap_size > diff_word_gap)
-	    {
-		dp = dp->df_next;
-		continue;
-	    }
-
-	    // Get the text between the two blocks
-	    char_u *line = ml_get_buf(curtab->tp_diffbuf[idx1],
-		    start_lnum + entry1->lineoff, FALSE);
-	    char_u *gap_text = line + gap_start;
-
-	    // Check if gap contains only whitespace and/or punctuation
-	    bool only_non_word = true;
-	    bool has_content = false;
-
-	    for (int i = 0; i < gap_size && gap_text[i] != NUL; i++)
-	    {
-		has_content = true;
-		int char_class = mb_get_class_buf(gap_text + i,
-				curtab->tp_diffbuf[idx1]);
-		// class 2 is word characters, if we find any, don't merge
-		if (char_class == 2)
-		{
-		    only_non_word = false;
-		    break;
-		}
-	    }
-
-	    // Merge if the gap is small and contains only non-word characters
-	    if (has_content && only_non_word)
-	    {
-		long total_change_bytes = 0;
-		for (int i = 0; i < DB_COUNT; i++)
-		{
-		    if (curtab->tp_diffbuf[i] != NULL)
-		    {
-			// count bytes in the first block
-			for (int k = 0; k < dp->df_count[i]; k++)
-			{
-			    int idx = dp->df_lnum[i] + k - 1;
-			    if (idx < linemap[i].ga_len)
-				total_change_bytes +=
-				    ((linemap_entry_T *)linemap[i].ga_data)[idx].num_bytes;
-			}
-			// count bytes in the next block
-			for (int k = 0; k < dp->df_next->df_count[i]; k++)
-			{
-			    int idx = dp->df_next->df_lnum[i] + k - 1;
-			    if (idx < linemap[i].ga_len)
-				total_change_bytes +=
-				    ((linemap_entry_T *)linemap[i].ga_data)[idx].num_bytes;
-			}
-		    }
-		}
-
-		if (total_change_bytes >= gap_size * 2)
-		{
-		    // Merge the blocks by extending the first block to include the next
-		    for (int i = 0; i < DB_COUNT; i++)
-		    {
-			if (curtab->tp_diffbuf[i] != NULL)
-			{
-			    dp->df_count[i] = dp->df_next->df_lnum[i]
-				+ dp->df_next->df_count[i] - dp->df_lnum[i];
-			}
-		    }
-
-		    diff_T *dp_next = dp->df_next;
-		    dp->df_next = dp_next->df_next;
-		    clear_diffblock(dp_next);
-
-		    // Don't advance dp, check if can merge with the next block too
-		    continue;
-		}
-	    }
-
-	    dp = dp->df_next;
-	}
-    } while (pass++ < 4);  // use limited number of passes to avoid excessive looping
-}
-
-/*
- * Find the inline difference within a diff block among different buffers.  Do
- * this by splitting each block's content into characters or words, and then
- * use internal xdiff to calculate the per-character/word diff.  The result is
- * stored in dp instead of returned by the function.
- */
-    static void
-diff_find_change_inline_diff(
-    diff_T	*dp)
-{
-    diffio_T	dio;
-    garray_T	linemap[DB_COUNT];
-    garray_T	file1_str;
-    garray_T	file2_str;
-    int		file1_idx = -1;
-
-    long	save_diff_algorithm = diff_algorithm;
-
-    CLEAR_FIELD(dio);
-    ga_init2(&dio.dio_diff.dout_ga, sizeof(char *), 1000);
-
-    // inline diff only supports internal algo
-    dio.dio_internal = TRUE;
-
-    // always use indent-heuristics to slide diff splits along
-    // whitespace
-    diff_algorithm |= XDF_INDENT_HEURISTIC;
-
-    // diff_read() has an implicit dependency on curtab->tp_first_diff
-    diff_T	*orig_diff = curtab->tp_first_diff;
-    curtab->tp_first_diff = NULL;
-
-    // diff_read() also uses curtab->tp_diffbuf to determine what's an active
-    // buffer
-    buf_T	*(orig_diffbuf[DB_COUNT]);
-    memcpy(orig_diffbuf, curtab->tp_diffbuf, sizeof(orig_diffbuf));
-
-    // Buffers to populate mmfile 1/2 that would be passed to xdiff as memory
-    // files. Use a grow array as it is not obvious how much exact space we
-    // need.
-    ga_init2(&file1_str, 1, 1024);
-    ga_init2(&file2_str, 1, 1024);
-
-    // Line map to map from generated mmfiles' line numbers back to original
-    // diff blocks' locations. Need this even for char diff because not all
-    // characters are 1-byte long / ASCII.
-    for (int i = 0; i < DB_COUNT; i++)
-	ga_init2(&linemap[i], sizeof(linemap_entry_T), 128);
-
-    for (int i = 0; i < DB_COUNT; i++)
-    {
-	dio.dio_diff.dout_ga.ga_len = 0;
-
-	buf_T *buf = curtab->tp_diffbuf[i];
-	if (buf == NULL || buf->b_ml.ml_mfp == NULL)
-	    continue; // skip buffer that isn't loaded
-
-	if (dp->df_count[i] == 0)
-	{
-	    // skip buffers that don't have any texts in this block so we don't
-	    // end up marking the entire block as modified in multi-buffer diff
-	    curtab->tp_diffbuf[i] = NULL;
-	    continue;
-	}
-
-	if (file1_idx == -1)
-	    file1_idx = i;
-
-	garray_T	*curstr = (file1_idx != i) ? &file2_str : &file1_str;
-
-	linenr_T numlines = 0;
-	curstr->ga_len = 0;
-
-	// Split each line into chars/words and populate fake file buffer as
-	// newline-delimited tokens as that's what xdiff requires.
-	for (int off = 0; off < dp->df_count[i]; off++)
-	{
-	    char_u *curline = ml_get_buf(curtab->tp_diffbuf[i],
-		    dp->df_lnum[i] + off, FALSE);
-
-	    int in_keyword = FALSE;
-
-	    // iwhiteeol support vars
-	    int last_white = FALSE;
-	    int eol_ga_len = -1;
-	    int eol_linemap_len = -1;
-	    int eol_numlines = -1;
-
-	    char_u *s;
-	    for (s = curline; *s != NUL;)
-	    {
-		int new_in_keyword = FALSE;
-		if (diff_flags & DIFF_INLINE_WORD)
-		{
-		    // Always use the first buffer's 'iskeyword' to have a
-		    // consistent diff.
-		    // For multibyte chars, only treat alphanumeric chars
-		    // (class 2) as "word", as other classes such as emojis and
-		    // CJK ideographs do not usually benefit from word diff as
-		    // MNV doesn't have a good way to segment them.
-		    new_in_keyword = (mb_get_class_buf(s, curtab->tp_diffbuf[file1_idx]) == 2);
-		}
-		if (in_keyword && !new_in_keyword)
-		{
-		    ga_append(curstr, NL);
-		    numlines++;
-		}
-
-		if (MNV_ISWHITE(*s))
-		{
-		    if (diff_flags & DIFF_IWHITEALL)
-		    {
-			in_keyword = FALSE;
-			s = skipwhite(s);
-			continue;
-		    }
-		    else if ((diff_flags & DIFF_IWHITEEOL) || (diff_flags & DIFF_IWHITE))
-		    {
-			if (!last_white)
-			{
-			    eol_ga_len = curstr->ga_len;
-			    eol_linemap_len = linemap[i].ga_len;
-			    eol_numlines = numlines;
-			    last_white = TRUE;
-			}
-		    }
-		}
-		else
-		{
-		    if ((diff_flags & DIFF_IWHITEEOL) || (diff_flags & DIFF_IWHITE))
-		    {
-			last_white = FALSE;
-			eol_ga_len = -1;
-			eol_linemap_len = -1;
-			eol_numlines = -1;
-		    }
-		}
-
-		int char_len = 1;
-		if (*s == NL)
-		    // NL is internal substitute for NUL
-		    ga_append(curstr, NUL);
-		else
-		{
-		    char_len = mb_ptr2len(s);
-
-		    if (MNV_ISWHITE(*s) && (diff_flags & DIFF_IWHITE))
-			// Treat the entire white space span as a single char.
-			char_len = skipwhite(s) - s;
-
-		    if (diff_flags & DIFF_ICASE)
-		    {
-			int c;
-			char_u cbuf[MB_MAXBYTES + 1];
-			// xdiff doesn't support ignoring case, fold-case the text manually.
-			c = PTR2CHAR(s);
-			int c_len = MB_CHAR2LEN(c);
-			c = MB_CASEFOLD(c);
-			int c_fold_len = mb_char2bytes(c, cbuf);
-			ga_concat_len(curstr, cbuf, c_fold_len);
-			if (char_len > c_len)
-			{
-			    // There may be remaining composing characters. Write those back in.
-			    // Composing characters don't need case folding.
-			    ga_concat_len(curstr, s + c_len, char_len - c_len);
-			}
-		    }
-		    else
-			ga_concat_len(curstr, s, char_len);
-		}
-
-		if (!new_in_keyword)
-		{
-		    ga_append(curstr, NL);
-		    numlines++;
-		}
-
-		if (!new_in_keyword || (new_in_keyword && !in_keyword))
-		{
-		    // create a new mapping entry from the xdiff mmfile back to
-		    // original line/col.
-		    linemap_entry_T linemap_entry;
-		    linemap_entry.lineoff = off;
-		    linemap_entry.byte_start = s - curline;
-		    linemap_entry.num_bytes = char_len;
-		    if (ga_grow(&linemap[i], 1) != OK)
-			goto done;
-		    ((linemap_entry_T*)(linemap[i].ga_data))[linemap[i].ga_len]
-			= linemap_entry;
-		    linemap[i].ga_len += 1;
-		}
-		else
-		{
-		    // Still inside a keyword. Just increment byte count but
-		    // don't make a new entry.
-		    // linemap always has at least one entry here
-		    ((linemap_entry_T*)linemap[i].ga_data)[linemap[i].ga_len-1].num_bytes
-			+= char_len;
-		}
-
-		in_keyword = new_in_keyword;
-		s += char_len;
-	    }
-	    if (in_keyword)
-	    {
-		ga_append(curstr, NL);
-		numlines++;
-	    }
-
-	    if ((diff_flags & DIFF_IWHITEEOL) || (diff_flags & DIFF_IWHITE))
-	    {
-		// Need to trim trailing whitespace. Do this simply by
-		// resetting arrays back to before we encountered them.
-		if (eol_ga_len != -1)
-		{
-		    curstr->ga_len = eol_ga_len;
-		    linemap[i].ga_len = eol_linemap_len;
-		    numlines = eol_numlines;
-		}
-	    }
-
-	    if (!(diff_flags & DIFF_IWHITEALL))
-	    {
-		// Add an empty line token mapped to the end-of-line in the
-		// original file. This helps diff newline differences among
-		// files, which will be visualized when using 'list' as the eol
-		// listchar will be highlighted.
-		ga_append(curstr, NL);
-		numlines++;
-
-		linemap_entry_T linemap_entry;
-		linemap_entry.lineoff = off;
-		linemap_entry.byte_start = s - curline;
-		linemap_entry.num_bytes = sizeof(NL);
-		if (ga_grow(&linemap[i], 1) != OK)
-		    goto done;
-		((linemap_entry_T*)(linemap[i].ga_data))[linemap[i].ga_len]
-		    = linemap_entry;
-		linemap[i].ga_len += 1;
-	    }
-	}
-
-	if (file1_idx != i)
-	{
-	    dio.dio_new.din_mmfile.ptr = (char *)curstr->ga_data;
-	    dio.dio_new.din_mmfile.size = curstr->ga_len;
-	}
-	else
-	{
-	    dio.dio_orig.din_mmfile.ptr = (char *)curstr->ga_data;
-	    dio.dio_orig.din_mmfile.size = curstr->ga_len;
-	}
-	if (file1_idx != i)
-	{
-	    // Perform diff with first file and read the results
-	    int diff_status = diff_file_internal(&dio);
-	    if (diff_status == FAIL)
-		goto done;
-
-	    diff_read(0, i, &dio);
-	    clear_diffout(&dio.dio_diff);
-	}
-    }
-    diff_T *new_diff = curtab->tp_first_diff;
-
-    if (diff_flags & DIFF_INLINE_WORD && file1_idx != -1)
-	diff_refine_inline_word_highlight(new_diff, linemap, file1_idx, dp->df_lnum[file1_idx]);
-    else if (diff_flags & DIFF_INLINE_CHAR && file1_idx != -1)
-	diff_refine_inline_char_highlight(new_diff, linemap, file1_idx);
-
-    // After the diff, use the linemap to obtain the original line/col of the
-    // changes and cache them in dp.
-    dp->df_changes.ga_len = 0; // this should already be zero
-    for (; new_diff != NULL; new_diff = new_diff->df_next)
-    {
-	diffline_change_T change;
-	CLEAR_FIELD(change);
-	for (int i = 0; i < DB_COUNT; i++)
-	{
-	    if (new_diff->df_lnum[i] <= 0) // should never be < 0. Checking just for safety.
-		continue;
-	    linenr_T diff_lnum = new_diff->df_lnum[i] - 1; // use zero-index
-	    linenr_T diff_lnum_end = diff_lnum + new_diff->df_count[i];
-
-	    if (diff_lnum >= linemap[i].ga_len)
-	    {
-		change.dc_start[i] = MAXCOL;
-		change.dc_start_lnum_off[i] = INT_MAX;
-	    }
-	    else
-	    {
-		change.dc_start[i] = ((linemap_entry_T*)linemap[i].ga_data)[diff_lnum].byte_start;
-		change.dc_start_lnum_off[i] = ((linemap_entry_T*)linemap[i].ga_data)[diff_lnum].lineoff;
-	    }
-
-	    if (diff_lnum == diff_lnum_end)
-	    {
-		change.dc_end[i] = change.dc_start[i];
-		change.dc_end_lnum_off[i] = change.dc_start_lnum_off[i];
-	    }
-	    else if (diff_lnum_end - 1 >= linemap[i].ga_len)
-	    {
-		change.dc_end[i] = MAXCOL;
-		change.dc_end_lnum_off[i] = INT_MAX;
-	    }
-	    else
-	    {
-		change.dc_end[i] = ((linemap_entry_T*)linemap[i].ga_data)[diff_lnum_end-1].byte_start +
-		    ((linemap_entry_T*)linemap[i].ga_data)[diff_lnum_end-1].num_bytes;
-		change.dc_end_lnum_off[i] = ((linemap_entry_T*)linemap[i].ga_data)[diff_lnum_end-1].lineoff;
-	    }
-	}
-	if (ga_grow(&dp->df_changes, 1) != OK)
-	{
-	    dp->df_changes.ga_len = 0;
-	    goto done;
-	}
-	((diffline_change_T*)(dp->df_changes.ga_data))[dp->df_changes.ga_len] = change;
-	dp->df_changes.ga_len += 1;
-    }
-
-done:
-    diff_algorithm = save_diff_algorithm;
-
-    dp->has_changes = TRUE;
-
-    diff_clear(curtab);
-    curtab->tp_first_diff = orig_diff;
-    memcpy(curtab->tp_diffbuf, orig_diffbuf, sizeof(orig_diffbuf));
-
-    ga_clear(&file1_str);
-    ga_clear(&file2_str);
-    // No need to clear dio.dio_orig/dio_new because they were referencing
-    // strings that are now cleared.
-    clear_diffout(&dio.dio_diff);
-    for (int i = 0; i < DB_COUNT; i++)
-	ga_clear(&linemap[i]);
-}
-
-/*
- * Find the difference within a changed line.
- * Returns TRUE if the line was added, no other buffer has it.
- */
-    int
-diff_find_change(
-    win_T	*wp,
-    linenr_T	lnum,
-    diffline_T	*diffline)
-{
-    diff_T	*dp;
-    int		idx;
-    int		off;
-
-    idx = diff_buf_idx(wp->w_buffer);
-    if (idx == DB_COUNT)	// cannot happen
-	return FALSE;
-
-    // search for a change that includes "lnum" in the list of diffblocks.
-    FOR_ALL_DIFFBLOCKS_IN_TAB(curtab, dp)
-	if (lnum < dp->df_lnum[idx] + dp->df_count[idx])
-	    break;
-    if (dp == NULL || diff_check_sanity(curtab, dp) == FAIL)
-	return FALSE;
-
-    if (lnum - dp->df_lnum[idx] > INT_MAX)
-	// Integer overflow protection
-	return FALSE;
-    off = lnum - dp->df_lnum[idx];
-
-    if (!(diff_flags & ALL_INLINE_DIFF) || diff_internal_failed())
-    {
-	// Use simple algorithm
-	int	change_start = MAXCOL;	// first col of changed area
-	int	change_end = -1;	// last col of changed area
-	int	ret;
-
-	ret = diff_find_change_simple(wp, lnum, dp, idx, &change_start, &change_end);
-
-	// convert from inclusive end to exclusive end per diffline's contract
-	change_end += 1;
-
-	// Create a mock diffline struct. We always only have one so no need to
-	// allocate memory.
-	CLEAR_FIELD(simple_diffline_change);
-	diffline->changes = &simple_diffline_change;
-	diffline->num_changes = 1;
-	diffline->bufidx = idx;
-	diffline->lineoff = lnum - dp->df_lnum[idx];
-
-	simple_diffline_change.dc_start[idx] = change_start;
-	simple_diffline_change.dc_end[idx] = change_end;
-	simple_diffline_change.dc_start_lnum_off[idx] = off;
-	simple_diffline_change.dc_end_lnum_off[idx] = off;
-	return ret;
-    }
-
-    // Use inline diff algorithm.
-    // The diff changes are usually cached so we check that first.
-    if (!dp->has_changes)
-	diff_find_change_inline_diff(dp);
-
-    garray_T *changes = &dp->df_changes;
-
-    // Use linear search to find the first change for this line. We could
-    // optimize this to use binary search, but there should usually be a
-    // limited number of inline changes per diff block, and limited number of
-    // diff blocks shown on screen, so it is not necessary.
-    int num_changes = 0;
-    int change_idx = 0;
-    diffline->changes = NULL;
-    for (change_idx = 0; change_idx < changes->ga_len; change_idx++)
-    {
-	diffline_change_T *change = &((diffline_change_T*)dp->df_changes.ga_data)[change_idx];
-	if (change->dc_end_lnum_off[idx] < off)
-	    continue;
-	if (change->dc_start_lnum_off[idx] > off)
-	    break;
-	if (diffline->changes == NULL)
-	    diffline->changes = change;
-	num_changes++;
-    }
-    diffline->num_changes = num_changes;
-    diffline->bufidx = idx;
-    diffline->lineoff = off;
-
-    // Detect simple cases of added lines in the end within a diff block. This
-    // has to be the last change of this diff block, and all other buffers are
-    // considering this to be an addition past their last line. Other scenarios
-    // will be considered a changed line instead.
-    int added = FALSE;
-    if (num_changes == 1 && change_idx == dp->df_changes.ga_len)
-    {
-	added = TRUE;
-	for (int i = 0; i < DB_COUNT; i++)
-	{
-	    if (idx == i)
-		continue;
-	    if (curtab->tp_diffbuf[i] == NULL)
-		continue;
-	    diffline_change_T *change = &((diffline_change_T*)dp->df_changes.ga_data)[dp->df_changes.ga_len-1];
-	    if (change->dc_start_lnum_off[i] != INT_MAX)
-	    {
-		added = FALSE;
-		break;
-	    }
-	}
-    }
-    return added;
-}
-
-# if defined(FEAT_FOLDING)
-/*
- * Return TRUE if line "lnum" is not close to a diff block, this line should
- * be in a fold.
- * Return FALSE if there are no diff blocks at all in this window.
- */
-    int
-diff_infold(win_T *wp, linenr_T lnum)
-{
-    int		i;
-    int		idx = -1;
-    int		other = FALSE;
-    diff_T	*dp;
-
-    // Return if 'diff' isn't set.
-    if (!wp->w_p_diff)
-	return FALSE;
-
-    for (i = 0; i < DB_COUNT; ++i)
-    {
-	if (curtab->tp_diffbuf[i] == wp->w_buffer)
-	    idx = i;
-	else if (curtab->tp_diffbuf[i] != NULL)
-	    other = TRUE;
-    }
-
-    // return here if there are no diffs in the window
-    if (idx == -1 || !other)
-	return FALSE;
-
-    if (curtab->tp_diff_invalid)
-	ex_diffupdate(NULL);		// update after a big change
-
-    // Return if there are no diff blocks.  All lines will be folded.
-    if (curtab->tp_first_diff == NULL)
-	return TRUE;
-
-    FOR_ALL_DIFFBLOCKS_IN_TAB(curtab, dp)
-    {
-	// If this change is below the line there can't be any further match.
-	if (dp->df_lnum[idx] - diff_context > lnum)
-	    break;
-	// If this change ends before the line we have a match.
-	if (dp->df_lnum[idx] + dp->df_count[idx] + diff_context > lnum)
-	    return FALSE;
-    }
-    return TRUE;
-}
-# endif
-
-/*
- * "dp" and "do" commands.
- */
-    void
-nv_diffgetput(int put, long count)
-{
-    exarg_T	ea;
-    char_u	buf[30];
-
-# ifdef FEAT_JOB_CHANNEL
-    if (bt_prompt(curbuf))
-    {
-	mnv_beep(BO_OPER);
-	return;
-    }
-# endif
-    if (count == 0)
-	ea.arg = (char_u *)"";
-    else
-    {
-	mnv_snprintf((char *)buf, 30, "%ld", count);
-	ea.arg = buf;
-    }
-    if (put)
-	ea.cmdidx = CMD_diffput;
-    else
-	ea.cmdidx = CMD_diffget;
-    ea.addr_count = 0;
-    ea.line1 = curwin->w_cursor.lnum;
-    ea.line2 = curwin->w_cursor.lnum;
-    ex_diffgetput(&ea);
-}
-
-/*
- * Return TRUE if "diff" appears in the list of diff blocks of the current tab.
- */
-    static int
-valid_diff(diff_T *diff)
-{
-    diff_T	*dp;
-
-    FOR_ALL_DIFFBLOCKS_IN_TAB(curtab, dp)
-	if (dp == diff)
-	    return TRUE;
-    return FALSE;
-}
-
-/*
- * ":diffget"
- * ":diffput"
- */
-    void
-ex_diffgetput(exarg_T *eap)
-{
-    linenr_T	lnum;
-    int		count;
-    linenr_T	off = 0;
-    diff_T	*dp;
-    diff_T	*dprev;
-    diff_T	*dfree;
-    int		idx_cur;
-    int		idx_other;
-    int		idx_from;
-    int		idx_to;
-    int		i;
-    int		added;
-    char_u	*p;
-    aco_save_T	aco;
-    buf_T	*buf;
-    int		start_skip, end_skip;
-    int		new_count;
-    int		buf_empty;
-    int		found_not_ma = FALSE;
-
-    // Find the current buffer in the list of diff buffers.
-    idx_cur = diff_buf_idx(curbuf);
-    if (idx_cur == DB_COUNT)
-    {
-	emsg(_(e_current_buffer_is_not_in_diff_mode));
-	return;
-    }
-
-    if (*eap->arg == NUL)
-    {
-	// No argument: Find the other buffer in the list of diff buffers.
-	for (idx_other = 0; idx_other < DB_COUNT; ++idx_other)
-	    if (curtab->tp_diffbuf[idx_other] != curbuf
-		    && curtab->tp_diffbuf[idx_other] != NULL)
-	    {
-		if (eap->cmdidx != CMD_diffput
-				     || curtab->tp_diffbuf[idx_other]->b_p_ma)
-		    break;
-		found_not_ma = TRUE;
-	    }
-	if (idx_other == DB_COUNT)
-	{
-	    if (found_not_ma)
-		emsg(_(e_no_other_buffer_in_diff_mode_is_modifiable));
-	    else
-		emsg(_(e_no_other_buffer_in_diff_mode));
-	    return;
-	}
-
-	// Check that there isn't a third buffer in the list
-	for (i = idx_other + 1; i < DB_COUNT; ++i)
-	    if (curtab->tp_diffbuf[i] != curbuf
-		    && curtab->tp_diffbuf[i] != NULL
-		    && (eap->cmdidx != CMD_diffput || curtab->tp_diffbuf[i]->b_p_ma))
-	    {
-		emsg(_(e_more_than_two_buffers_in_diff_mode_dont_know_which_one_to_use));
-		return;
-	    }
-    }
-    else
-    {
-	// Buffer number or pattern given.  Ignore trailing white space.
-	p = eap->arg + STRLEN(eap->arg);
-	while (p > eap->arg && MNV_ISWHITE(p[-1]))
-	    --p;
-	for (i = 0; mnv_isdigit(eap->arg[i]) && eap->arg + i < p; ++i)
-	    ;
-	if (eap->arg + i == p)	    // digits only
-	    i = atol((char *)eap->arg);
-	else
-	{
-	    i = buflist_findpat(eap->arg, p, FALSE, TRUE, FALSE);
-	    if (i < 0)
-		return;		// error message already given
-	}
-	buf = buflist_findnr(i);
-	if (buf == NULL)
-	{
-	    semsg(_(e_cant_find_buffer_str), eap->arg);
-	    return;
-	}
-	if (buf == curbuf)
-	    return;		// nothing to do
-	idx_other = diff_buf_idx(buf);
-	if (idx_other == DB_COUNT)
-	{
-	    semsg(_(e_buffer_str_is_not_in_diff_mode), eap->arg);
-	    return;
-	}
-    }
-
-    diff_busy = TRUE;
-
-    // When no range given include the line above or below the cursor.
-    if (eap->addr_count == 0)
-    {
-	// Make it possible that ":diffget" on the last line gets line below
-	// the cursor line when there is no difference above the cursor.
-	int linestatus = 0;
-	if (eap->line1 == curbuf->b_ml.ml_line_count
-		&& (diff_check_with_linestatus(curwin, eap->line1, &linestatus) == 0
-		    && linestatus == 0)
-		&& (eap->line1 == 1 ||
-		    (diff_check_with_linestatus(curwin, eap->line1 - 1, &linestatus) >= 0
-		     && linestatus == 0)))
-	    ++eap->line2;
-	else if (eap->line1 > 0)
-	    --eap->line1;
-    }
-
-    if (eap->cmdidx == CMD_diffget)
-    {
-	idx_from = idx_other;
-	idx_to = idx_cur;
-    }
-    else
-    {
-	idx_from = idx_cur;
-	idx_to = idx_other;
-	// Need to make the other buffer the current buffer to be able to make
-	// changes in it.
-	// Set curwin/curbuf to buf and save a few things.
-	aucmd_prepbuf(&aco, curtab->tp_diffbuf[idx_other]);
-	if (curbuf != curtab->tp_diffbuf[idx_other])
-	    // Could not find a window for this buffer, the rest is likely to
-	    // fail.
-	    goto theend;
-    }
-
-    // May give the warning for a changed buffer here, which can trigger the
-    // FileChangedRO autocommand, which may do nasty things and mess
-    // everything up.
-    if (!curbuf->b_changed)
-    {
-	change_warning(0);
-	if (diff_buf_idx(curbuf) != idx_to)
-	{
-	    emsg(_(e_buffer_changed_unexpectedly));
-	    goto theend;
-	}
-    }
-
-    dprev = NULL;
-    for (dp = curtab->tp_first_diff; dp != NULL; )
-    {
-	if (!eap->addr_count)
-	{
-	    // Handle the case with adjacent diff blocks (e.g. using linematch
-	    // or anchors) at/above the cursor. Since a range wasn't specified,
-	    // we just want to grab one diff block rather than all of them in
-	    // the vicinity.
-	    while (dp->df_next
-		    && dp->df_next->df_lnum[idx_cur] == dp->df_lnum[idx_cur] +
-							dp->df_count[idx_cur]
-		    && dp->df_next->df_lnum[idx_cur] == eap->line1 + off + 1)
-	    {
-		dprev = dp;
-		dp = dp->df_next;
-	    }
-	}
-	if (dp->df_lnum[idx_cur] > eap->line2 + off)
-	    break;	// past the range that was specified
-
-	dfree = NULL;
-	lnum = dp->df_lnum[idx_to];
-	count = dp->df_count[idx_to];
-	if (dp->df_lnum[idx_cur] + dp->df_count[idx_cur] > eap->line1 + off
-		&& u_save(lnum - 1, lnum + count) != FAIL)
-	{
-	    // Inside the specified range and saving for undo worked.
-	    start_skip = 0;
-	    end_skip = 0;
-	    if (eap->addr_count > 0)
-	    {
-		// A range was specified: check if lines need to be skipped.
-		start_skip = eap->line1 + off - dp->df_lnum[idx_cur];
-		if (start_skip > 0)
-		{
-		    // range starts below start of current diff block
-		    if (start_skip > count)
-		    {
-			lnum += count;
-			count = 0;
-		    }
-		    else
-		    {
-			count -= start_skip;
-			lnum += start_skip;
-		    }
-		}
-		else
-		    start_skip = 0;
-
-		end_skip = dp->df_lnum[idx_cur] + dp->df_count[idx_cur] - 1
-							 - (eap->line2 + off);
-		if (end_skip > 0)
-		{
-		    // range ends above end of current/from diff block
-		    if (idx_cur == idx_from)	// :diffput
-		    {
-			i = dp->df_count[idx_cur] - start_skip - end_skip;
-			if (count > i)
-			    count = i;
-		    }
-		    else			// :diffget
-		    {
-			count -= end_skip;
-			end_skip = dp->df_count[idx_from] - start_skip - count;
-			if (end_skip < 0)
-			    end_skip = 0;
-		    }
-		}
-		else
-		    end_skip = 0;
-	    }
-
-	    buf_empty = BUFEMPTY();
-	    added = 0;
-	    for (i = 0; i < count; ++i)
-	    {
-		// remember deleting the last line of the buffer
-		buf_empty = curbuf->b_ml.ml_line_count == 1;
-		if (ml_delete(lnum) == OK)
-		    --added;
-	    }
-	    for (i = 0; i < dp->df_count[idx_from] - start_skip - end_skip; ++i)
-	    {
-		linenr_T nr;
-
-		nr = dp->df_lnum[idx_from] + start_skip + i;
-		if (nr > curtab->tp_diffbuf[idx_from]->b_ml.ml_line_count)
-		    break;
-		p = mnv_strsave(ml_get_buf(curtab->tp_diffbuf[idx_from],
-								  nr, FALSE));
-		if (p != NULL)
-		{
-		    ml_append(lnum + i - 1, p, 0, FALSE);
-		    mnv_free(p);
-		    ++added;
-		    if (buf_empty && curbuf->b_ml.ml_line_count == 2)
-		    {
-			// Added the first line into an empty buffer, need to
-			// delete the dummy empty line.
-			buf_empty = FALSE;
-			ml_delete((linenr_T)2);
-		    }
-		}
-	    }
-	    new_count = dp->df_count[idx_to] + added;
-	    dp->df_count[idx_to] = new_count;
-
-	    if (start_skip == 0 && end_skip == 0)
-	    {
-		// Check if there are any other buffers and if the diff is
-		// equal in them.
-		for (i = 0; i < DB_COUNT; ++i)
-		    if (curtab->tp_diffbuf[i] != NULL && i != idx_from
-								&& i != idx_to
-			    && !diff_equal_entry(dp, idx_from, i))
-			break;
-		if (i == DB_COUNT)
-		{
-		    // delete the diff entry, the buffers are now equal here
-		    dfree = dp;
-		    dp = dp->df_next;
-		    if (dprev == NULL)
-			curtab->tp_first_diff = dp;
-		    else
-			dprev->df_next = dp;
-		}
-	    }
-
-	    if (added != 0)
-	    {
-		// Adjust marks.  This will change the following entries!
-		mark_adjust(lnum, lnum + count - 1, (long)MAXLNUM, (long)added);
-		if (curwin->w_cursor.lnum >= lnum)
-		{
-		    // Adjust the cursor position if it's in/after the changed
-		    // lines.
-		    if (curwin->w_cursor.lnum >= lnum + count)
-		    {
-			curwin->w_cursor.lnum += added;
-			// When the buffer was previously empty, the cursor may
-			// now be beyond the last line, so clamp cursor lnum.
-			curwin->w_cursor.lnum = MIN(curwin->w_cursor.lnum,
-						curbuf->b_ml.ml_line_count);
-		    }
-		    else if (added < 0)
-			curwin->w_cursor.lnum = lnum;
-		}
-	    }
-	    changed_lines(lnum, 0, lnum + count, (long)added);
-
-	    if (dfree != NULL)
-	    {
-		// Diff is deleted, update folds in other windows.
-# ifdef FEAT_FOLDING
-		diff_fold_update(dfree, idx_to);
-# endif
-		clear_diffblock(dfree);
-	    }
-
-	    // mark_adjust() may have made "dp" invalid.  We don't know where
-	    // to continue then, bail out.
-	    if (added != 0 && !valid_diff(dp))
-		break;
-
-	    if (dfree == NULL)
-		// mark_adjust() may have changed the count in a wrong way
-		dp->df_count[idx_to] = new_count;
-
-	    // When changing the current buffer, keep track of line numbers
-	    if (idx_cur == idx_to)
-		off += added;
-	}
-
-	// If before the range or not deleted, go to next diff.
-	if (dfree == NULL)
-	{
-	    dprev = dp;
-	    dp = dp->df_next;
-	}
-    }
-
-    // restore curwin/curbuf and a few other things
-    if (eap->cmdidx != CMD_diffget)
-    {
-	// Syncing undo only works for the current buffer, but we change
-	// another buffer.  Sync undo if the command was typed.  This isn't
-	// 100% right when ":diffput" is used in a function or mapping.
-	if (KeyTyped)
-	    u_sync(FALSE);
-	aucmd_restbuf(&aco);
-    }
-
-theend:
-    diff_busy = FALSE;
-    if (diff_need_update)
-	ex_diffupdate(NULL);
-
-    // Check that the cursor is on a valid character and update its
-    // position.  When there were filler lines the topline has become
-    // invalid.
-    check_cursor();
-    changed_line_abv_curs();
-
-# ifdef FEAT_FOLDING
-    // If all diffs are gone, update folds in all diff windows.
-    if (curtab->tp_first_diff == NULL)
-    {
-	win_T	*wp;
-
-	FOR_ALL_WINDOWS_IN_TAB(curtab, wp)
-	    if (wp->w_p_diff && wp->w_p_fdm[0] == 'd' && wp->w_p_fen)
-		foldUpdateAll(wp);
-    }
-# endif
-
-    if (diff_need_update)
-	// redraw already done by ex_diffupdate()
-	diff_need_update = FALSE;
-    else
-    {
-	// Also need to redraw the other buffers.
-	diff_redraw(FALSE);
-	apply_autocmds(EVENT_DIFFUPDATED, NULL, NULL, FALSE, curbuf);
-    }
-}
-
-# ifdef FEAT_FOLDING
-/*
- * Update folds for all diff buffers for entry "dp".
- * Skip buffer with index "skip_idx".
- * When there are no diffs, all folds are removed.
- */
-    static void
-diff_fold_update(diff_T *dp, int skip_idx)
-{
-    int		i;
-    win_T	*wp;
-
-    FOR_ALL_WINDOWS(wp)
-	for (i = 0; i < DB_COUNT; ++i)
-	    if (curtab->tp_diffbuf[i] == wp->w_buffer && i != skip_idx)
-		foldUpdate(wp, dp->df_lnum[i],
-					    dp->df_lnum[i] + dp->df_count[i]);
-}
-# endif
-
-/*
- * Return TRUE if buffer "buf" is in diff-mode.
- */
-    int
-diff_mode_buf(buf_T *buf)
-{
-    tabpage_T	*tp;
-
-    FOR_ALL_TABPAGES(tp)
-	if (diff_buf_idx_tp(buf, tp) != DB_COUNT)
-	    return TRUE;
-    return FALSE;
-}
-
-/*
- * Move "count" times in direction "dir" to the next diff block.
- * Return FAIL if there isn't such a diff block.
- */
-    int
-diff_move_to(int dir, long count)
-{
-    int		idx;
-    linenr_T	lnum = curwin->w_cursor.lnum;
-    diff_T	*dp;
-
-    idx = diff_buf_idx(curbuf);
-    if (idx == DB_COUNT || curtab->tp_first_diff == NULL)
-	return FAIL;
-
-    if (curtab->tp_diff_invalid)
-	ex_diffupdate(NULL);		// update after a big change
-
-    if (curtab->tp_first_diff == NULL)		// no diffs today
-	return FAIL;
-
-    while (--count >= 0)
-    {
-	// Check if already before first diff.
-	if (dir == BACKWARD && lnum <= curtab->tp_first_diff->df_lnum[idx])
-	    break;
-
-	for (dp = curtab->tp_first_diff; ; dp = dp->df_next)
-	{
-	    if (dp == NULL)
-		break;
-	    if ((dir == FORWARD && lnum < dp->df_lnum[idx])
-		    || (dir == BACKWARD
-			&& (dp->df_next == NULL
-			    || lnum <= dp->df_next->df_lnum[idx])))
-	    {
-		lnum = dp->df_lnum[idx];
-		break;
-	    }
-	}
-    }
-
-    // don't end up past the end of the file
-    if (lnum > curbuf->b_ml.ml_line_count)
-	lnum = curbuf->b_ml.ml_line_count;
-
-    // When the cursor didn't move at all we fail.
-    if (lnum == curwin->w_cursor.lnum)
-	return FAIL;
-
-    setpcmark();
-    curwin->w_cursor.lnum = lnum;
-    curwin->w_cursor.col = 0;
-
-    return OK;
-}
-
-/*
- * Return the line number in the current window that is closest to "lnum1" in
- * "buf1" in diff mode.
- */
-    static linenr_T
-diff_get_corresponding_line_int(
-    buf_T	*buf1,
-    linenr_T	lnum1)
-{
-    int		idx1;
-    int		idx2;
-    diff_T	*dp;
-    int		baseline = 0;
-
-    idx1 = diff_buf_idx(buf1);
-    idx2 = diff_buf_idx(curbuf);
-    if (idx1 == DB_COUNT || idx2 == DB_COUNT || curtab->tp_first_diff == NULL)
-	return lnum1;
-
-    if (curtab->tp_diff_invalid)
-	ex_diffupdate(NULL);		// update after a big change
-
-    if (curtab->tp_first_diff == NULL)		// no diffs today
-	return lnum1;
-
-    FOR_ALL_DIFFBLOCKS_IN_TAB(curtab, dp)
-    {
-	if (dp->df_lnum[idx1] > lnum1)
-	    return lnum1 - baseline;
-	if ((dp->df_lnum[idx1] + dp->df_count[idx1]) > lnum1)
-	{
-	    // Inside the diffblock
-	    baseline = lnum1 - dp->df_lnum[idx1];
-	    if (baseline > dp->df_count[idx2])
-		baseline = dp->df_count[idx2];
-
-	    return dp->df_lnum[idx2] + baseline;
-	}
-	if (    (dp->df_lnum[idx1] == lnum1)
-	     && (dp->df_count[idx1] == 0)
-	     && (dp->df_lnum[idx2] <= curwin->w_cursor.lnum)
-	     && ((dp->df_lnum[idx2] + dp->df_count[idx2])
-						      > curwin->w_cursor.lnum))
-	    /*
-	     * Special case: if the cursor is just after a zero-count
-	     * block (i.e. all filler) and the target cursor is already
-	     * inside the corresponding block, leave the target cursor
-	     * unmoved. This makes repeated CTRL-W W operations work
-	     * as expected.
-	     */
-	    return curwin->w_cursor.lnum;
-	baseline = (dp->df_lnum[idx1] + dp->df_count[idx1])
-				   - (dp->df_lnum[idx2] + dp->df_count[idx2]);
-    }
-
-    // If we get here then the cursor is after the last diff
-    return lnum1 - baseline;
-}
-
-/*
- * Return the line number in the current window that is closest to "lnum1" in
- * "buf1" in diff mode.  Checks the line number to be valid.
- */
-    linenr_T
-diff_get_corresponding_line(buf_T *buf1, linenr_T lnum1)
-{
-    linenr_T lnum = diff_get_corresponding_line_int(buf1, lnum1);
-
-    // don't end up past the end of the file
-    if (lnum > curbuf->b_ml.ml_line_count)
-	return curbuf->b_ml.ml_line_count;
-    return lnum;
-}
-
-/*
- * For line "lnum" in the current window find the equivalent lnum in window
- * "wp", compensating for inserted/deleted lines.
- */
-    linenr_T
-diff_lnum_win(linenr_T lnum, win_T *wp)
-{
-    diff_T	*dp;
-    int		idx;
-    int		i;
-    linenr_T	n;
-
-    idx = diff_buf_idx(curbuf);
-    if (idx == DB_COUNT)		// safety check
-	return (linenr_T)0;
-
-    if (curtab->tp_diff_invalid)
-	ex_diffupdate(NULL);		// update after a big change
-
-    // search for a change that includes "lnum" in the list of diffblocks.
-    FOR_ALL_DIFFBLOCKS_IN_TAB(curtab, dp)
-	if (lnum <= dp->df_lnum[idx] + dp->df_count[idx])
-	    break;
-
-    // When after the last change, compute relative to the last line number.
-    if (dp == NULL)
-	return wp->w_buffer->b_ml.ml_line_count
-					- (curbuf->b_ml.ml_line_count - lnum);
-
-    // Find index for "wp".
-    i = diff_buf_idx(wp->w_buffer);
-    if (i == DB_COUNT)			// safety check
-	return (linenr_T)0;
-
-    n = lnum + (dp->df_lnum[i] - dp->df_lnum[idx]);
-    if (n > dp->df_lnum[i] + dp->df_count[i])
-	n = dp->df_lnum[i] + dp->df_count[i];
-    return n;
-}
-
-/*
- * Handle an ED style diff line.
- * Return FAIL if the line does not contain diff info.
- */
-    static int
-parse_diff_ed(
-	char_u	    *line,
-	diffhunk_T  *hunk)
-{
-    char_u *p;
-    long    f1, l1, f2, l2;
-    int	    difftype;
-
-    // The line must be one of three formats:
-    // change: {first}[,{last}]c{first}[,{last}]
-    // append: {first}a{first}[,{last}]
-    // delete: {first}[,{last}]d{first}
-    p = line;
-    f1 = getdigits(&p);
-    if (*p == ',')
-    {
-	++p;
-	l1 = getdigits(&p);
-    }
-    else
-	l1 = f1;
-    if (*p != 'a' && *p != 'c' && *p != 'd')
-	return FAIL;		// invalid diff format
-    difftype = *p++;
-    f2 = getdigits(&p);
-    if (*p == ',')
-    {
-	++p;
-	l2 = getdigits(&p);
-    }
-    else
-	l2 = f2;
-    if (l1 < f1 || l2 < f2)
-	return FAIL;
-
-    if (difftype == 'a')
-    {
-	hunk->lnum_orig = f1 + 1;
-	hunk->count_orig = 0;
-    }
-    else
-    {
-	hunk->lnum_orig = f1;
-	hunk->count_orig = l1 - f1 + 1;
-    }
-    if (difftype == 'd')
-    {
-	hunk->lnum_new = f2 + 1;
-	hunk->count_new = 0;
-    }
-    else
-    {
-	hunk->lnum_new = f2;
-	hunk->count_new = l2 - f2 + 1;
-    }
-    return OK;
-}
-
-/*
- * Parses unified diff with zero(!) context lines.
- * Return FAIL if there is no diff information in "line".
- */
-    static int
-parse_diff_unified(
-	char_u	    *line,
-	diffhunk_T  *hunk)
-{
-    char_u *p;
-    long    oldline, oldcount, newline, newcount;
-
-    // Parse unified diff hunk header:
-    // @@ -oldline,oldcount +newline,newcount @@
-    p = line;
-    if (*p++ == '@' && *p++ == '@' && *p++ == ' ' && *p++ == '-')
-    {
-	oldline = getdigits(&p);
-	if (*p == ',')
-	{
-	    ++p;
-	    oldcount = getdigits(&p);
-	}
-	else
-	    oldcount = 1;
-	if (*p++ == ' ' && *p++ == '+')
-	{
-	    newline = getdigits(&p);
-	    if (*p == ',')
-	    {
-		++p;
-		newcount = getdigits(&p);
-	    }
-	    else
-		newcount = 1;
-	}
-	else
-	    return FAIL;	// invalid diff format
-
-	if (oldcount == 0)
-	    oldline += 1;
-	if (newcount == 0)
-	    newline += 1;
-	if (newline == 0)
-	    newline = 1;
-
-	hunk->lnum_orig = oldline;
-	hunk->count_orig = oldcount;
-	hunk->lnum_new = newline;
-	hunk->count_new = newcount;
-
-	return OK;
-    }
-
-    return FAIL;
-}
-
-/*
- * Callback function for the xdl_diff() function.
- * Stores the diff output (indices) in a grow array.
- */
-    static int
-xdiff_out_indices(
-	long start_a,
-	long count_a,
-	long start_b,
-	long count_b,
-	void *priv)
-{
-    diffout_T	*dout = (diffout_T *)priv;
-    diffhunk_T *p = ALLOC_ONE(diffhunk_T);
-
-    if (p == NULL)
-	return -1;
-
-    if (ga_grow(&dout->dout_ga, 1) == FAIL)
-    {
-	mnv_free(p);
-	return -1;
-    }
-
-    p->lnum_orig  = start_a + 1;
-    p->count_orig = count_a;
-    p->lnum_new   = start_b + 1;
-    p->count_new  = count_b;
-    ((diffhunk_T **)dout->dout_ga.ga_data)[dout->dout_ga.ga_len++] = p;
-    return 0;
-}
-
-/*
- * Callback function for the xdl_diff() function.
- * Stores the unified diff output in a grow array.
- */
-    static int
-xdiff_out_unified(
-	void *priv,
-	mmbuffer_t *mb,
-	int nbuf)
-{
-    diffout_T	*dout = (diffout_T *)priv;
-    int		i;
-
-    for (i = 0; i < nbuf; i++)
-	ga_concat_len(&dout->dout_ga, (char_u *)mb[i].ptr, mb[i].size);
-
-    return 0;
-}
-
-#endif	// FEAT_DIFF
-
-#if defined(FEAT_EVAL)
-
-/*
- * "diff_filler()" function
- */
-    void
-f_diff_filler(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
-{
-# ifdef FEAT_DIFF
-    if (in_mnv9script() && check_for_lnum_arg(argvars, 0) == FAIL)
-	return;
-
-    rettv->vval.v_number = diff_check_fill(curwin, tv_get_lnum(argvars));
-# endif
-}
-
-/*
- * "diff_hlID()" function
- */
-    void
-f_diff_hlID(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
-{
-# ifdef FEAT_DIFF
-    linenr_T		lnum;
-    static linenr_T	prev_lnum = 0;
-    static varnumber_T	changedtick = 0;
-    static int		fnum = 0;
-    static int		prev_diff_flags = 0;
-    static int		change_start = 0;
-    static int		change_end = 0;
-    static hlf_T	hlID = (hlf_T)0;
-    int			cache_results = TRUE;
-    int			col;
-    diffline_T		diffline;
-
-    CLEAR_FIELD(diffline);
-
-    if (in_mnv9script()
-	    && (check_for_lnum_arg(argvars,0) == FAIL
-		|| check_for_number_arg(argvars, 1) == FAIL))
-	return;
-
-    if (diff_flags & ALL_INLINE_DIFF)
-    {
-	// Remember the results if using simple since it's recalculated per
-	// call. Otherwise just call diff_find_change() every time since
-	// internally the result is cached internally.
-	cache_results = FALSE;
-    }
-
-    lnum = tv_get_lnum(argvars);
-    if (lnum < 0)	// ignore type error in {lnum} arg
-	lnum = 0;
-    if (!cache_results
-	    || lnum != prev_lnum
-	    || changedtick != CHANGEDTICK(curbuf)
-	    || fnum != curbuf->b_fnum
-	    || diff_flags != prev_diff_flags)
-    {
-	// New line, buffer, change: need to get the values.
-	int linestatus = 0;
-	diff_check_with_linestatus(curwin, lnum, &linestatus);
-	if (linestatus < 0)
-	{
-	    if (linestatus == -1)
-	    {
-		change_start = MAXCOL;
-		change_end = -1;
-		if (diff_find_change(curwin, lnum, &diffline))
-		    hlID = HLF_ADD;	// added line
-		else
-		{
-		    hlID = HLF_CHD;	// changed line
-		    if (diffline.num_changes > 0 && cache_results)
-		    {
-			change_start = diffline.changes[0].dc_start[diffline.bufidx];
-			change_end = diffline.changes[0].dc_end[diffline.bufidx];
-		    }
-		}
-	    }
-	    else
-		hlID = HLF_ADD;	// added line
-	}
-	else
-	    hlID = (hlf_T)0;
-
-	if (cache_results)
-	{
-	    prev_lnum = lnum;
-	    changedtick = CHANGEDTICK(curbuf);
-	    fnum = curbuf->b_fnum;
-	    prev_diff_flags = diff_flags;
-	}
-    }
-
-    if (hlID == HLF_CHD || hlID == HLF_TXD)
-    {
-	col = tv_get_number(&argvars[1]) - 1; // ignore type error in {col}
-	if (cache_results)
-	{
-	    if (col >= change_start && col < change_end)
-		hlID = HLF_TXD;			// changed text
-	    else
-		hlID = HLF_CHD;			// changed line
-	}
-	else
-	{
-	    hlID = HLF_CHD;
-	    for (int i = 0; i < diffline.num_changes; i++)
-	    {
-		int added = diff_change_parse(&diffline, &diffline.changes[i],
-			&change_start, &change_end);
-		if (col >= change_start && col < change_end)
-		{
-		    hlID = added ? HLF_TXA : HLF_TXD;
-		    break;
-		}
-		if (col < change_start)
-		    // the remaining changes are past this column and not relevant
-		    break;
-	    }
-	}
-    }
-    rettv->vval.v_number = hlID == (hlf_T)0 ? 0 : (int)hlID;
-# endif
-}
-
-# ifdef FEAT_DIFF
-/*
- * Parse the diff options passed in "optarg" to the diff() function and return
- * the options in "diffopts" and the diff algorithm in "diffalgo".
- */
-    static int
-parse_diff_optarg(
-    typval_T	    *opts,
-    int		    *diffopts,
-    long	    *diffalgo,
-    dio_outfmt_T    *diff_output_fmt,
-    int		    *diff_ctxlen)
-{
-    dict_T *d = opts->vval.v_dict;
-
-    char_u  *algo = dict_get_string(d, "algorithm", FALSE);
-    if (algo != NULL)
-    {
-	if (STRNCMP(algo, "myers", 5) == 0)
-	    *diffalgo = 0;
-	else if (STRNCMP(algo, "minimal", 7) == 0)
-	    *diffalgo = XDF_NEED_MINIMAL;
-	else if (STRNCMP(algo, "patience", 8) == 0)
-	    *diffalgo = XDF_PATIENCE_DIFF;
-	else if (STRNCMP(algo, "histogram", 9) == 0)
-	    *diffalgo = XDF_HISTOGRAM_DIFF;
-    }
-
-    char_u  *output_fmt = dict_get_string(d, "output", FALSE);
-    if (output_fmt != NULL)
-    {
-	if (STRNCMP(output_fmt, "unified", 7) == 0)
-	    *diff_output_fmt = DIO_OUTPUT_UNIFIED;
-	else if (STRNCMP(output_fmt, "indices", 7) == 0)
-	    *diff_output_fmt = DIO_OUTPUT_INDICES;
-	else
-	{
-	    semsg(_(e_unsupported_diff_output_format_str), output_fmt);
-	    return FAIL;
-	}
-    }
-
-    *diff_ctxlen = dict_get_number_def(d, "context", 0);
-    if (*diff_ctxlen < 0)
-	*diff_ctxlen = 0;
-
-    if (dict_get_bool(d, "iblank", FALSE))
-	*diffopts |= DIFF_IBLANK;
-    if (dict_get_bool(d, "icase", FALSE))
-	*diffopts |= DIFF_ICASE;
-    if (dict_get_bool(d, "iwhite", FALSE))
-	*diffopts |= DIFF_IWHITE;
-    if (dict_get_bool(d, "iwhiteall", FALSE))
-	*diffopts |= DIFF_IWHITEALL;
-    if (dict_get_bool(d, "iwhiteeol", FALSE))
-	*diffopts |= DIFF_IWHITEEOL;
-    if (dict_get_bool(d, "indent-heuristic", FALSE))
-	*diffalgo |= XDF_INDENT_HEURISTIC;
-
-    return OK;
-}
-
-/*
- * Concatenate the List of strings in "l" and store the result in
- * "din->din_mmfile.ptr" and the length in "din->din_mmfile.size".
- */
-    static void
-list_to_diffin(list_T *l, diffin_T *din, int icase)
-{
-    garray_T	ga;
-    listitem_T	*li;
-    char_u	*str;
-
-    ga_init2(&ga, 1, 2048);
-
-    FOR_ALL_LIST_ITEMS(l, li)
-    {
-	str = tv_get_string(&li->li_tv);
-	if (icase)
-	{
-	    str = strlow_save(str);
-	    if (str == NULL)
-		continue;
-	}
-	ga_concat(&ga, str);
-	ga_append(&ga, NL);
-	if (icase)
-	    mnv_free(str);
-    }
-
-    din->din_mmfile.ptr = (char *)ga.ga_data;
-    din->din_mmfile.size = ga.ga_len;
-}
-
-/*
- * Get the start and end indices from the diff "hunk".
- */
-    static dict_T *
-get_diff_hunk_indices(diffhunk_T *hunk)
-{
-    dict_T	*hunk_dict;
-
-    hunk_dict = dict_alloc();
-    if (hunk_dict == NULL)
-	return NULL;
-
-    dict_add_number(hunk_dict, "from_idx", hunk->lnum_orig - 1);
-    dict_add_number(hunk_dict, "from_count", hunk->count_orig);
-    dict_add_number(hunk_dict, "to_idx", hunk->lnum_new  - 1);
-    dict_add_number(hunk_dict, "to_count", hunk->count_new);
-
-    return hunk_dict;
-}
-# endif
-
-/*
- * "diff()" function
- */
-    void
-f_diff(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
-{
-# ifdef FEAT_DIFF
-    diffio_T dio;
-
-    if (check_for_nonnull_list_arg(argvars, 0) == FAIL
-	    || check_for_nonnull_list_arg(argvars, 1) == FAIL
-	    || check_for_opt_nonnull_dict_arg(argvars, 2) == FAIL)
-	return;
-
-    CLEAR_FIELD(dio);
-    dio.dio_internal = TRUE;
-    ga_init2(&dio.dio_diff.dout_ga, sizeof(char *), 1000);
-
-    list_T *orig_list = argvars[0].vval.v_list;
-    list_T *new_list = argvars[1].vval.v_list;
-
-    // Save the 'diffopt' option value and restore it after getting the diff.
-    int		save_diff_flags = diff_flags;
-    long	save_diff_algorithm = diff_algorithm;
-    diff_flags = DIFF_INTERNAL;
-    diff_algorithm = 0;
-    dio.dio_outfmt = DIO_OUTPUT_UNIFIED;
-    if (argvars[2].v_type != VAR_UNKNOWN)
-	if (parse_diff_optarg(&argvars[2], &diff_flags, &diff_algorithm,
-			&dio.dio_outfmt, &dio.dio_ctxlen) == FAIL)
-	    return;
-
-    // Concatenate the List of strings into a single string using newline
-    // separator.  Internal diff library expects a single string.
-    list_to_diffin(orig_list, &dio.dio_orig, diff_flags & DIFF_ICASE);
-    list_to_diffin(new_list, &dio.dio_new, diff_flags & DIFF_ICASE);
-
-    // If 'diffexpr' is set, then the internal diff is not used.  Set
-    // 'diffexpr' to an empty string temporarily.
-    int	    restore_diffexpr = FALSE;
-    char_u  cc = *p_dex;
-    if (*p_dex != NUL)
-    {
-	restore_diffexpr = TRUE;
-	*p_dex = NUL;
-    }
-
-    // Compute the diff
-    int diff_status = diff_file(&dio);
-
-    // restore 'diffexpr'
-    if (restore_diffexpr)
-	*p_dex = cc;
-
-    if (diff_status == FAIL)
-	goto done;
-
-    int		hunk_idx = 0;
-    dict_T	*hunk_dict;
-
-    if (dio.dio_outfmt == DIO_OUTPUT_INDICES)
-    {
-	if (rettv_list_alloc(rettv) != OK)
-	    goto done;
-	list_T	*l = rettv->vval.v_list;
-
-	// Process each diff hunk
-	diffhunk_T	*hunk = NULL;
-	while (hunk_idx < dio.dio_diff.dout_ga.ga_len)
-	{
-	    hunk = ((diffhunk_T **)dio.dio_diff.dout_ga.ga_data)[hunk_idx++];
-
-	    hunk_dict = get_diff_hunk_indices(hunk);
-	    if (hunk_dict == NULL)
-		goto done;
-
-	    list_append_dict(l, hunk_dict);
-	}
-    }
-    else
-    {
-	ga_append(&dio.dio_diff.dout_ga, NUL);
-	rettv->v_type = VAR_STRING;
-	rettv->vval.v_string =
-			mnv_strsave((char_u *)dio.dio_diff.dout_ga.ga_data);
-    }
-
-done:
-    clear_diffin(&dio.dio_new);
-    if (dio.dio_outfmt == DIO_OUTPUT_INDICES)
-	clear_diffout(&dio.dio_diff);
-    else
-	ga_clear(&dio.dio_diff.dout_ga);
-    clear_diffin(&dio.dio_orig);
-    // Restore the 'diffopt' option value.
-    diff_flags = save_diff_flags;
-    diff_algorithm = save_diff_algorithm;
-# endif
-}
-
-#endif