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+/* vi:set ts=8 sts=4 sw=4:
+ *
+ * VIM - Vi IMproved by Bram Moolenaar
+ *
+ * Do ":help uganda" in Vim to read copying and usage conditions.
+ * Do ":help credits" in Vim to see a list of people who contributed.
+ * See README.txt for an overview of the Vim source code.
+ */
+/*
+ * move.c: Functions for moving the cursor and scrolling text.
+ *
+ * There are two ways to move the cursor:
+ * 1. Move the cursor directly, the text is scrolled to keep the cursor in the
+ * window.
+ * 2. Scroll the text, the cursor is moved into the text visible in the
+ * window.
+ * The 'scrolloff' option makes this a bit complicated.
+ */
+
+#include "vim.h"
+
+static void comp_botline __ARGS((win_T *wp));
+static int scrolljump_value __ARGS((void));
+static int check_top_offset __ARGS((void));
+static void curs_rows __ARGS((win_T *wp, int do_botline));
+static void validate_botline_win __ARGS((win_T *wp));
+static void validate_cheight __ARGS((void));
+
+typedef struct
+{
+ linenr_T lnum; /* line number */
+#ifdef FEAT_DIFF
+ int fill; /* filler lines */
+#endif
+ int height; /* height of added line */
+} lineoff_T;
+
+static void topline_back __ARGS((lineoff_T *lp));
+static void botline_forw __ARGS((lineoff_T *lp));
+#ifdef FEAT_DIFF
+static void botline_topline __ARGS((lineoff_T *lp));
+static void topline_botline __ARGS((lineoff_T *lp));
+static void max_topfill __ARGS((void));
+#endif
+
+/*
+ * Compute wp->w_botline for the current wp->w_topline. Can be called after
+ * wp->w_topline changed.
+ */
+ static void
+comp_botline(wp)
+ win_T *wp;
+{
+ int n;
+ linenr_T lnum;
+ int done;
+#ifdef FEAT_FOLDING
+ linenr_T last;
+ int folded;
+#endif
+
+ /*
+ * If w_cline_row is valid, start there.
+ * Otherwise have to start at w_topline.
+ */
+ check_cursor_moved(wp);
+ if (wp->w_valid & VALID_CROW)
+ {
+ lnum = wp->w_cursor.lnum;
+ done = wp->w_cline_row;
+ }
+ else
+ {
+ lnum = wp->w_topline;
+ done = 0;
+ }
+
+ for ( ; lnum <= wp->w_buffer->b_ml.ml_line_count; ++lnum)
+ {
+#ifdef FEAT_FOLDING
+ last = lnum;
+ folded = FALSE;
+ if (hasFoldingWin(wp, lnum, NULL, &last, TRUE, NULL))
+ {
+ n = 1;
+ folded = TRUE;
+ }
+ else
+#endif
+#ifdef FEAT_DIFF
+ if (lnum == wp->w_topline)
+ n = plines_win_nofill(wp, lnum, TRUE) + wp->w_topfill;
+ else
+#endif
+ n = plines_win(wp, lnum, TRUE);
+ if (
+#ifdef FEAT_FOLDING
+ lnum <= wp->w_cursor.lnum && last >= wp->w_cursor.lnum
+#else
+ lnum == wp->w_cursor.lnum
+#endif
+ )
+ {
+ wp->w_cline_row = done;
+ wp->w_cline_height = n;
+#ifdef FEAT_FOLDING
+ wp->w_cline_folded = folded;
+#endif
+ wp->w_valid |= (VALID_CROW|VALID_CHEIGHT);
+ }
+ if (done + n > wp->w_height)
+ break;
+ done += n;
+#ifdef FEAT_FOLDING
+ lnum = last;
+#endif
+ }
+
+ /* wp->w_botline is the line that is just below the window */
+ wp->w_botline = lnum;
+ wp->w_valid |= VALID_BOTLINE|VALID_BOTLINE_AP;
+
+ set_empty_rows(wp, done);
+}
+
+/*
+ * Update curwin->w_topline and redraw if necessary.
+ * Used to update the screen before printing a message.
+ */
+ void
+update_topline_redraw()
+{
+ update_topline();
+ if (must_redraw)
+ update_screen(0);
+}
+
+/*
+ * Update curwin->w_topline to move the cursor onto the screen.
+ */
+ void
+update_topline()
+{
+ long line_count;
+ int halfheight;
+ int n;
+ linenr_T old_topline;
+#ifdef FEAT_DIFF
+ int old_topfill;
+#endif
+#ifdef FEAT_FOLDING
+ linenr_T lnum;
+#endif
+ int check_topline = FALSE;
+ int check_botline = FALSE;
+#ifdef FEAT_MOUSE
+ int save_so = p_so;
+#endif
+
+ if (!screen_valid(TRUE))
+ return;
+
+ check_cursor_moved(curwin);
+ if (curwin->w_valid & VALID_TOPLINE)
+ return;
+
+#ifdef FEAT_MOUSE
+ /* When dragging with the mouse, don't scroll that quickly */
+ if (mouse_dragging > 0)
+ p_so = mouse_dragging - 1;
+#endif
+
+ old_topline = curwin->w_topline;
+#ifdef FEAT_DIFF
+ old_topfill = curwin->w_topfill;
+#endif
+
+ /*
+ * If the buffer is empty, always set topline to 1.
+ */
+ if (bufempty()) /* special case - file is empty */
+ {
+ if (curwin->w_topline != 1)
+ redraw_later(NOT_VALID);
+ curwin->w_topline = 1;
+ curwin->w_botline = 2;
+ curwin->w_valid |= VALID_BOTLINE|VALID_BOTLINE_AP;
+#ifdef FEAT_SCROLLBIND
+ curwin->w_scbind_pos = 1;
+#endif
+ }
+
+ /*
+ * If the cursor is above or near the top of the window, scroll the window
+ * to show the line the cursor is in, with 'scrolloff' context.
+ */
+ else
+ {
+ if (curwin->w_topline > 1)
+ {
+ /* If the cursor is above topline, scrolling is always needed.
+ * If the cursor is far below topline and there is no folding,
+ * scrolling down is never needed. */
+ if (curwin->w_cursor.lnum < curwin->w_topline)
+ check_topline = TRUE;
+ else if (check_top_offset())
+ check_topline = TRUE;
+ }
+#ifdef FEAT_DIFF
+ /* Check if there are more filler lines than allowed. */
+ if (!check_topline && curwin->w_topfill > diff_check_fill(curwin,
+ curwin->w_topline))
+ check_topline = TRUE;
+#endif
+
+ if (check_topline)
+ {
+ halfheight = curwin->w_height / 2 - 1;
+ if (halfheight < 2)
+ halfheight = 2;
+
+#ifdef FEAT_FOLDING
+ if (hasAnyFolding(curwin))
+ {
+ /* Count the number of logical lines between the cursor and
+ * topline + p_so (approximation of how much will be
+ * scrolled). */
+ n = 0;
+ for (lnum = curwin->w_cursor.lnum;
+ lnum < curwin->w_topline + p_so; ++lnum)
+ {
+ ++n;
+ /* stop at end of file or when we know we are far off */
+ if (lnum >= curbuf->b_ml.ml_line_count || n >= halfheight)
+ break;
+ (void)hasFolding(lnum, NULL, &lnum);
+ }
+ }
+ else
+#endif
+ n = curwin->w_topline + p_so - curwin->w_cursor.lnum;
+
+ /* If we weren't very close to begin with, we scroll to put the
+ * cursor in the middle of the window. Otherwise put the cursor
+ * near the top of the window. */
+ if (n >= halfheight)
+ scroll_cursor_halfway(FALSE);
+ else
+ {
+ scroll_cursor_top(scrolljump_value(), FALSE);
+ check_botline = TRUE;
+ }
+ }
+
+ else
+ {
+#ifdef FEAT_FOLDING
+ /* Make sure topline is the first line of a fold. */
+ (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
+#endif
+ check_botline = TRUE;
+ }
+ }
+
+ /*
+ * If the cursor is below the bottom of the window, scroll the window
+ * to put the cursor on the window.
+ * When w_botline is invalid, recompute it first, to avoid a redraw later.
+ * If w_botline was approximated, we might need a redraw later in a few
+ * cases, but we don't want to spend (a lot of) time recomputing w_botline
+ * for every small change.
+ */
+ if (check_botline)
+ {
+ if (!(curwin->w_valid & VALID_BOTLINE_AP))
+ validate_botline();
+
+ if (curwin->w_botline <= curbuf->b_ml.ml_line_count)
+ {
+ if (curwin->w_cursor.lnum < curwin->w_botline)
+ {
+ if (((long)curwin->w_cursor.lnum
+ >= (long)curwin->w_botline - p_so
+#ifdef FEAT_FOLDING
+ || hasAnyFolding(curwin)
+#endif
+ ))
+ {
+ lineoff_T loff;
+
+ /* Cursor is (a few lines) above botline, check if there are
+ * 'scrolloff' window lines below the cursor. If not, need to
+ * scroll. */
+ n = curwin->w_empty_rows;
+ loff.lnum = curwin->w_cursor.lnum;
+#ifdef FEAT_FOLDING
+ /* In a fold go to its last line. */
+ (void)hasFolding(loff.lnum, NULL, &loff.lnum);
+#endif
+#ifdef FEAT_DIFF
+ loff.fill = 0;
+ n += curwin->w_filler_rows;
+#endif
+ loff.height = 0;
+ while (loff.lnum < curwin->w_botline
+#ifdef FEAT_DIFF
+ && (loff.lnum + 1 < curwin->w_botline || loff.fill == 0)
+#endif
+ )
+ {
+ n += loff.height;
+ if (n >= p_so)
+ break;
+ botline_forw(&loff);
+ }
+ if (n >= p_so)
+ /* sufficient context, no need to scroll */
+ check_botline = FALSE;
+ }
+ else
+ /* sufficient context, no need to scroll */
+ check_botline = FALSE;
+ }
+ if (check_botline)
+ {
+#ifdef FEAT_FOLDING
+ if (hasAnyFolding(curwin))
+ {
+ /* Count the number of logical lines between the cursor and
+ * botline - p_so (approximation of how much will be
+ * scrolled). */
+ line_count = 0;
+ for (lnum = curwin->w_cursor.lnum;
+ lnum >= curwin->w_botline - p_so; --lnum)
+ {
+ ++line_count;
+ /* stop at end of file or when we know we are far off */
+ if (lnum <= 0 || line_count > curwin->w_height + 1)
+ break;
+ (void)hasFolding(lnum, &lnum, NULL);
+ }
+ }
+ else
+#endif
+ line_count = curwin->w_cursor.lnum - curwin->w_botline
+ + 1 + p_so;
+ if (line_count <= curwin->w_height + 1)
+ scroll_cursor_bot(scrolljump_value(), FALSE);
+ else
+ scroll_cursor_halfway(FALSE);
+ }
+ }
+ }
+ curwin->w_valid |= VALID_TOPLINE;
+
+ /*
+ * Need to redraw when topline changed.
+ */
+ if (curwin->w_topline != old_topline
+#ifdef FEAT_DIFF
+ || curwin->w_topfill != old_topfill
+#endif
+ )
+ {
+ dollar_vcol = 0;
+ if (curwin->w_skipcol != 0)
+ {
+ curwin->w_skipcol = 0;
+ redraw_later(NOT_VALID);
+ }
+ else
+ redraw_later(VALID);
+ /* May need to set w_skipcol when cursor in w_topline. */
+ if (curwin->w_cursor.lnum == curwin->w_topline)
+ validate_cursor();
+ }
+
+#ifdef FEAT_MOUSE
+ p_so = save_so;
+#endif
+}
+
+/*
+ * Return the scrolljump value to use for the current window.
+ * When 'scrolljump' is positive use it as-is.
+ * When 'scrolljump' is negative use it as a percentage of the window height.
+ */
+ static int
+scrolljump_value()
+{
+ if (p_sj >= 0)
+ return (int)p_sj;
+ return (curwin->w_height * -p_sj) / 100;
+}
+
+/*
+ * Return TRUE when there are not 'scrolloff' lines above the cursor for the
+ * current window.
+ */
+ static int
+check_top_offset()
+{
+ lineoff_T loff;
+ int n;
+
+ if (curwin->w_cursor.lnum < curwin->w_topline + p_so
+#ifdef FEAT_FOLDING
+ || hasAnyFolding(curwin)
+#endif
+ )
+ {
+ loff.lnum = curwin->w_cursor.lnum;
+#ifdef FEAT_DIFF
+ loff.fill = 0;
+ n = curwin->w_topfill; /* always have this context */
+#else
+ n = 0;
+#endif
+ /* Count the visible screen lines above the cursor line. */
+ while (n < p_so)
+ {
+ topline_back(&loff);
+ /* Stop when included a line above the window. */
+ if (loff.lnum < curwin->w_topline
+#ifdef FEAT_DIFF
+ || (loff.lnum == curwin->w_topline && loff.fill > 0)
+#endif
+ )
+ break;
+ n += loff.height;
+ }
+ if (n < p_so)
+ return TRUE;
+ }
+ return FALSE;
+}
+
+ void
+update_curswant()
+{
+ if (curwin->w_set_curswant)
+ {
+ validate_virtcol();
+ curwin->w_curswant = curwin->w_virtcol;
+ curwin->w_set_curswant = FALSE;
+ }
+}
+
+/*
+ * Check if the cursor has moved. Set the w_valid flag accordingly.
+ */
+ void
+check_cursor_moved(wp)
+ win_T *wp;
+{
+ if (wp->w_cursor.lnum != wp->w_valid_cursor.lnum)
+ {
+ wp->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL
+ |VALID_CHEIGHT|VALID_CROW|VALID_TOPLINE);
+ wp->w_valid_cursor = wp->w_cursor;
+ wp->w_valid_leftcol = wp->w_leftcol;
+ }
+ else if (wp->w_cursor.col != wp->w_valid_cursor.col
+ || wp->w_leftcol != wp->w_valid_leftcol
+#ifdef FEAT_VIRTUALEDIT
+ || wp->w_cursor.coladd != wp->w_valid_cursor.coladd
+#endif
+ )
+ {
+ wp->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL);
+ wp->w_valid_cursor.col = wp->w_cursor.col;
+ wp->w_valid_leftcol = wp->w_leftcol;
+#ifdef FEAT_VIRTUALEDIT
+ wp->w_valid_cursor.coladd = wp->w_cursor.coladd;
+#endif
+ }
+}
+
+/*
+ * Call this function when some window settings have changed, which require
+ * the cursor position, botline and topline to be recomputed and the window to
+ * be redrawn. E.g, when changing the 'wrap' option or folding.
+ */
+ void
+changed_window_setting()
+{
+ changed_window_setting_win(curwin);
+}
+
+ void
+changed_window_setting_win(wp)
+ win_T *wp;
+{
+ wp->w_lines_valid = 0;
+ changed_line_abv_curs_win(wp);
+ wp->w_valid &= ~(VALID_BOTLINE|VALID_BOTLINE_AP|VALID_TOPLINE);
+ redraw_win_later(wp, NOT_VALID);
+}
+
+/*
+ * Set wp->w_topline to a certain number.
+ */
+ void
+set_topline(wp, lnum)
+ win_T *wp;
+ linenr_T lnum;
+{
+#ifdef FEAT_FOLDING
+ /* go to first of folded lines */
+ (void)hasFoldingWin(wp, lnum, &lnum, NULL, TRUE, NULL);
+#endif
+ /* Approximate the value of w_botline */
+ wp->w_botline += lnum - wp->w_topline;
+ wp->w_topline = lnum;
+#ifdef FEAT_AUTOCMD
+ wp->w_topline_was_set = TRUE;
+#endif
+#ifdef FEAT_DIFF
+ wp->w_topfill = 0;
+#endif
+ wp->w_valid &= ~(VALID_WROW|VALID_CROW|VALID_BOTLINE|VALID_TOPLINE);
+ /* Don't set VALID_TOPLINE here, 'scrolloff' needs to be checked. */
+ redraw_later(VALID);
+}
+
+/*
+ * Call this function when the length of the cursor line (in screen
+ * characters) has changed, and the change is before the cursor.
+ * Need to take care of w_botline separately!
+ */
+ void
+changed_cline_bef_curs()
+{
+ curwin->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL
+ |VALID_CHEIGHT|VALID_TOPLINE);
+}
+
+ void
+changed_cline_bef_curs_win(wp)
+ win_T *wp;
+{
+ wp->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL
+ |VALID_CHEIGHT|VALID_TOPLINE);
+}
+
+/*
+ * Call this function when the length of a line (in screen characters) above
+ * the cursor have changed.
+ * Need to take care of w_botline separately!
+ */
+ void
+changed_line_abv_curs()
+{
+ curwin->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL|VALID_CROW
+ |VALID_CHEIGHT|VALID_TOPLINE);
+}
+
+ void
+changed_line_abv_curs_win(wp)
+ win_T *wp;
+{
+ wp->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL|VALID_CROW
+ |VALID_CHEIGHT|VALID_TOPLINE);
+}
+
+/*
+ * Make sure the value of curwin->w_botline is valid.
+ */
+ void
+validate_botline()
+{
+ if (!(curwin->w_valid & VALID_BOTLINE))
+ comp_botline(curwin);
+}
+
+/*
+ * Make sure the value of wp->w_botline is valid.
+ */
+ static void
+validate_botline_win(wp)
+ win_T *wp;
+{
+ if (!(wp->w_valid & VALID_BOTLINE))
+ comp_botline(wp);
+}
+
+/*
+ * Mark curwin->w_botline as invalid (because of some change in the buffer).
+ */
+ void
+invalidate_botline()
+{
+ curwin->w_valid &= ~(VALID_BOTLINE|VALID_BOTLINE_AP);
+}
+
+ void
+invalidate_botline_win(wp)
+ win_T *wp;
+{
+ wp->w_valid &= ~(VALID_BOTLINE|VALID_BOTLINE_AP);
+}
+
+ void
+approximate_botline_win(wp)
+ win_T *wp;
+{
+ wp->w_valid &= ~VALID_BOTLINE;
+}
+
+/*
+ * Return TRUE if curwin->w_wrow and curwin->w_wcol are valid.
+ */
+ int
+cursor_valid()
+{
+ check_cursor_moved(curwin);
+ return ((curwin->w_valid & (VALID_WROW|VALID_WCOL)) ==
+ (VALID_WROW|VALID_WCOL));
+}
+
+/*
+ * Validate cursor position. Makes sure w_wrow and w_wcol are valid.
+ * w_topline must be valid, you may need to call update_topline() first!
+ */
+ void
+validate_cursor()
+{
+ check_cursor_moved(curwin);
+ if ((curwin->w_valid & (VALID_WCOL|VALID_WROW)) != (VALID_WCOL|VALID_WROW))
+ curs_columns(TRUE);
+}
+
+#if defined(FEAT_GUI) || defined(PROTO)
+/*
+ * validate w_cline_row.
+ */
+ void
+validate_cline_row()
+{
+ /*
+ * First make sure that w_topline is valid (after moving the cursor).
+ */
+ update_topline();
+ check_cursor_moved(curwin);
+ if (!(curwin->w_valid & VALID_CROW))
+ curs_rows(curwin, FALSE);
+}
+#endif
+
+/*
+ * Compute wp->w_cline_row and wp->w_cline_height, based on the current value
+ * of wp->w_topline.
+ *
+ * Returns OK when cursor is in the window, FAIL when it isn't.
+ */
+ static void
+curs_rows(wp, do_botline)
+ win_T *wp;
+ int do_botline; /* also compute w_botline */
+{
+ linenr_T lnum;
+ int i;
+ int all_invalid;
+ int valid;
+#ifdef FEAT_FOLDING
+ long fold_count;
+#endif
+
+ /* Check if wp->w_lines[].wl_size is invalid */
+ all_invalid = (!redrawing()
+ || wp->w_lines_valid == 0
+ || wp->w_lines[0].wl_lnum > wp->w_topline);
+ i = 0;
+ wp->w_cline_row = 0;
+ for (lnum = wp->w_topline; lnum < wp->w_cursor.lnum; ++i)
+ {
+ valid = FALSE;
+ if (!all_invalid && i < wp->w_lines_valid)
+ {
+ if (wp->w_lines[i].wl_lnum < lnum || !wp->w_lines[i].wl_valid)
+ continue; /* skip changed or deleted lines */
+ if (wp->w_lines[i].wl_lnum == lnum)
+ {
+#ifdef FEAT_FOLDING
+ /* Check for newly inserted lines below this row, in which
+ * case we need to check for folded lines. */
+ if (!wp->w_buffer->b_mod_set
+ || wp->w_lines[i].wl_lastlnum < wp->w_cursor.lnum
+ || wp->w_buffer->b_mod_top
+ > wp->w_lines[i].wl_lastlnum + 1)
+#endif
+ valid = TRUE;
+ }
+ else if (wp->w_lines[i].wl_lnum > lnum)
+ --i; /* hold at inserted lines */
+ }
+ if (valid
+#ifdef FEAT_DIFF
+ && (lnum != wp->w_topline || !wp->w_p_diff)
+#endif
+ )
+ {
+#ifdef FEAT_FOLDING
+ lnum = wp->w_lines[i].wl_lastlnum + 1;
+ /* Cursor inside folded lines, don't count this row */
+ if (lnum > wp->w_cursor.lnum)
+ break;
+#else
+ ++lnum;
+#endif
+ wp->w_cline_row += wp->w_lines[i].wl_size;
+ }
+ else
+ {
+#ifdef FEAT_FOLDING
+ fold_count = foldedCount(wp, lnum, NULL);
+ if (fold_count)
+ {
+ lnum += fold_count;
+ if (lnum > wp->w_cursor.lnum)
+ break;
+ ++wp->w_cline_row;
+ }
+ else
+#endif
+#ifdef FEAT_DIFF
+ if (lnum == wp->w_topline)
+ wp->w_cline_row += plines_win_nofill(wp, lnum++, TRUE)
+ + wp->w_topfill;
+ else
+#endif
+ wp->w_cline_row += plines_win(wp, lnum++, TRUE);
+ }
+ }
+
+ check_cursor_moved(wp);
+ if (!(wp->w_valid & VALID_CHEIGHT))
+ {
+ if (all_invalid
+ || i == wp->w_lines_valid
+ || (i < wp->w_lines_valid
+ && (!wp->w_lines[i].wl_valid
+ || wp->w_lines[i].wl_lnum != wp->w_cursor.lnum)))
+ {
+#ifdef FEAT_DIFF
+ if (wp->w_cursor.lnum == wp->w_topline)
+ wp->w_cline_height = plines_win_nofill(wp, wp->w_cursor.lnum,
+ TRUE) + wp->w_topfill;
+ else
+#endif
+ wp->w_cline_height = plines_win(wp, wp->w_cursor.lnum, TRUE);
+#ifdef FEAT_FOLDING
+ wp->w_cline_folded = hasFoldingWin(wp, wp->w_cursor.lnum,
+ NULL, NULL, TRUE, NULL);
+#endif
+ }
+ else if (i > wp->w_lines_valid)
+ {
+ /* a line that is too long to fit on the last screen line */
+ wp->w_cline_height = 0;
+#ifdef FEAT_FOLDING
+ wp->w_cline_folded = hasFoldingWin(wp, wp->w_cursor.lnum,
+ NULL, NULL, TRUE, NULL);
+#endif
+ }
+ else
+ {
+ wp->w_cline_height = wp->w_lines[i].wl_size;
+#ifdef FEAT_FOLDING
+ wp->w_cline_folded = wp->w_lines[i].wl_folded;
+#endif
+ }
+ }
+
+ wp->w_valid |= VALID_CROW|VALID_CHEIGHT;
+
+ /* validate botline too, if update_screen doesn't do it */
+ if (do_botline && all_invalid)
+ validate_botline_win(wp);
+}
+
+/*
+ * Validate curwin->w_virtcol only.
+ */
+ void
+validate_virtcol()
+{
+ validate_virtcol_win(curwin);
+}
+
+/*
+ * Validate wp->w_virtcol only.
+ */
+ void
+validate_virtcol_win(wp)
+ win_T *wp;
+{
+ check_cursor_moved(wp);
+ if (!(wp->w_valid & VALID_VIRTCOL))
+ {
+ getvvcol(wp, &wp->w_cursor, NULL, &(wp->w_virtcol), NULL);
+ wp->w_valid |= VALID_VIRTCOL;
+#ifdef FEAT_SYN_HL
+ if (wp->w_p_cuc
+# ifdef FEAT_INS_EXPAND
+ && !pum_visible()
+# endif
+ )
+ redraw_win_later(wp, SOME_VALID);
+#endif
+ }
+}
+
+/*
+ * Validate curwin->w_cline_height only.
+ */
+ static void
+validate_cheight()
+{
+ check_cursor_moved(curwin);
+ if (!(curwin->w_valid & VALID_CHEIGHT))
+ {
+#ifdef FEAT_DIFF
+ if (curwin->w_cursor.lnum == curwin->w_topline)
+ curwin->w_cline_height = plines_nofill(curwin->w_cursor.lnum)
+ + curwin->w_topfill;
+ else
+#endif
+ curwin->w_cline_height = plines(curwin->w_cursor.lnum);
+#ifdef FEAT_FOLDING
+ curwin->w_cline_folded = hasFolding(curwin->w_cursor.lnum, NULL, NULL);
+#endif
+ curwin->w_valid |= VALID_CHEIGHT;
+ }
+}
+
+/*
+ * Validate w_wcol and w_virtcol only.
+ */
+ void
+validate_cursor_col()
+{
+ colnr_T off;
+ colnr_T col;
+ int width;
+
+ validate_virtcol();
+ if (!(curwin->w_valid & VALID_WCOL))
+ {
+ col = curwin->w_virtcol;
+ off = curwin_col_off();
+ col += off;
+ width = W_WIDTH(curwin) - off + curwin_col_off2();
+
+ /* long line wrapping, adjust curwin->w_wrow */
+ if (curwin->w_p_wrap
+ && col >= (colnr_T)W_WIDTH(curwin)
+ && width > 0)
+ /* use same formula as what is used in curs_columns() */
+ col -= ((col - W_WIDTH(curwin)) / width + 1) * width;
+ if (col > (int)curwin->w_leftcol)
+ col -= curwin->w_leftcol;
+ else
+ col = 0;
+ curwin->w_wcol = col;
+
+ curwin->w_valid |= VALID_WCOL;
+ }
+}
+
+/*
+ * Compute offset of a window, occupied by absolute or relative line number,
+ * fold column and sign column (these don't move when scrolling horizontally).
+ */
+ int
+win_col_off(wp)
+ win_T *wp;
+{
+ return (((wp->w_p_nu || wp->w_p_rnu) ? number_width(wp) + 1 : 0)
+#ifdef FEAT_CMDWIN
+ + (cmdwin_type == 0 || wp != curwin ? 0 : 1)
+#endif
+#ifdef FEAT_FOLDING
+ + wp->w_p_fdc
+#endif
+#ifdef FEAT_SIGNS
+ + (
+# ifdef FEAT_NETBEANS_INTG
+ /* show glyph gutter in netbeans */
+ netbeans_active() ||
+# endif
+ wp->w_buffer->b_signlist != NULL ? 2 : 0)
+#endif
+ );
+}
+
+ int
+curwin_col_off()
+{
+ return win_col_off(curwin);
+}
+
+/*
+ * Return the difference in column offset for the second screen line of a
+ * wrapped line. It's 8 if 'number' or 'relativenumber' is on and 'n' is in
+ * 'cpoptions'.
+ */
+ int
+win_col_off2(wp)
+ win_T *wp;
+{
+ if ((wp->w_p_nu || wp->w_p_rnu) && vim_strchr(p_cpo, CPO_NUMCOL) != NULL)
+ return number_width(wp) + 1;
+ return 0;
+}
+
+ int
+curwin_col_off2()
+{
+ return win_col_off2(curwin);
+}
+
+/*
+ * compute curwin->w_wcol and curwin->w_virtcol.
+ * Also updates curwin->w_wrow and curwin->w_cline_row.
+ * Also updates curwin->w_leftcol.
+ */
+ void
+curs_columns(scroll)
+ int scroll; /* when TRUE, may scroll horizontally */
+{
+ int diff;
+ int extra; /* offset for first screen line */
+ int off_left, off_right;
+ int n;
+ int p_lines;
+ int width = 0;
+ int textwidth;
+ int new_leftcol;
+ colnr_T startcol;
+ colnr_T endcol;
+ colnr_T prev_skipcol;
+
+ /*
+ * First make sure that w_topline is valid (after moving the cursor).
+ */
+ update_topline();
+
+ /*
+ * Next make sure that w_cline_row is valid.
+ */
+ if (!(curwin->w_valid & VALID_CROW))
+ curs_rows(curwin, FALSE);
+
+ /*
+ * Compute the number of virtual columns.
+ */
+#ifdef FEAT_FOLDING
+ if (curwin->w_cline_folded)
+ /* In a folded line the cursor is always in the first column */
+ startcol = curwin->w_virtcol = endcol = curwin->w_leftcol;
+ else
+#endif
+ getvvcol(curwin, &curwin->w_cursor,
+ &startcol, &(curwin->w_virtcol), &endcol);
+
+ /* remove '$' from change command when cursor moves onto it */
+ if (startcol > dollar_vcol)
+ dollar_vcol = 0;
+
+ extra = curwin_col_off();
+ curwin->w_wcol = curwin->w_virtcol + extra;
+ endcol += extra;
+
+ /*
+ * Now compute w_wrow, counting screen lines from w_cline_row.
+ */
+ curwin->w_wrow = curwin->w_cline_row;
+
+ textwidth = W_WIDTH(curwin) - extra;
+ if (textwidth <= 0)
+ {
+ /* No room for text, put cursor in last char of window. */
+ curwin->w_wcol = W_WIDTH(curwin) - 1;
+ curwin->w_wrow = curwin->w_height - 1;
+ }
+ else if (curwin->w_p_wrap
+#ifdef FEAT_VERTSPLIT
+ && curwin->w_width != 0
+#endif
+ )
+ {
+ width = textwidth + curwin_col_off2();
+
+ /* long line wrapping, adjust curwin->w_wrow */
+ if (curwin->w_wcol >= W_WIDTH(curwin))
+ {
+ /* this same formula is used in validate_cursor_col() */
+ n = (curwin->w_wcol - W_WIDTH(curwin)) / width + 1;
+ curwin->w_wcol -= n * width;
+ curwin->w_wrow += n;
+
+#ifdef FEAT_LINEBREAK
+ /* When cursor wraps to first char of next line in Insert
+ * mode, the 'showbreak' string isn't shown, backup to first
+ * column */
+ if (*p_sbr && *ml_get_cursor() == NUL
+ && curwin->w_wcol == (int)vim_strsize(p_sbr))
+ curwin->w_wcol = 0;
+#endif
+ }
+ }
+
+ /* No line wrapping: compute curwin->w_leftcol if scrolling is on and line
+ * is not folded.
+ * If scrolling is off, curwin->w_leftcol is assumed to be 0 */
+ else if (scroll
+#ifdef FEAT_FOLDING
+ && !curwin->w_cline_folded
+#endif
+ )
+ {
+ /*
+ * If Cursor is left of the screen, scroll rightwards.
+ * If Cursor is right of the screen, scroll leftwards
+ * If we get closer to the edge than 'sidescrolloff', scroll a little
+ * extra
+ */
+ off_left = (int)startcol - (int)curwin->w_leftcol - p_siso;
+ off_right = (int)endcol - (int)(curwin->w_leftcol + W_WIDTH(curwin)
+ - p_siso) + 1;
+ if (off_left < 0 || off_right > 0)
+ {
+ if (off_left < 0)
+ diff = -off_left;
+ else
+ diff = off_right;
+
+ /* When far off or not enough room on either side, put cursor in
+ * middle of window. */
+ if (p_ss == 0 || diff >= textwidth / 2 || off_right >= off_left)
+ new_leftcol = curwin->w_wcol - extra - textwidth / 2;
+ else
+ {
+ if (diff < p_ss)
+ diff = p_ss;
+ if (off_left < 0)
+ new_leftcol = curwin->w_leftcol - diff;
+ else
+ new_leftcol = curwin->w_leftcol + diff;
+ }
+ if (new_leftcol < 0)
+ new_leftcol = 0;
+ if (new_leftcol != (int)curwin->w_leftcol)
+ {
+ curwin->w_leftcol = new_leftcol;
+ /* screen has to be redrawn with new curwin->w_leftcol */
+ redraw_later(NOT_VALID);
+ }
+ }
+ curwin->w_wcol -= curwin->w_leftcol;
+ }
+ else if (curwin->w_wcol > (int)curwin->w_leftcol)
+ curwin->w_wcol -= curwin->w_leftcol;
+ else
+ curwin->w_wcol = 0;
+
+#ifdef FEAT_DIFF
+ /* Skip over filler lines. At the top use w_topfill, there
+ * may be some filler lines above the window. */
+ if (curwin->w_cursor.lnum == curwin->w_topline)
+ curwin->w_wrow += curwin->w_topfill;
+ else
+ curwin->w_wrow += diff_check_fill(curwin, curwin->w_cursor.lnum);
+#endif
+
+ prev_skipcol = curwin->w_skipcol;
+
+ p_lines = 0;
+ if ((curwin->w_wrow >= curwin->w_height
+ || ((prev_skipcol > 0
+ || curwin->w_wrow + p_so >= curwin->w_height)
+ && (p_lines =
+#ifdef FEAT_DIFF
+ plines_win_nofill
+#else
+ plines_win
+#endif
+ (curwin, curwin->w_cursor.lnum, FALSE))
+ - 1 >= curwin->w_height))
+ && curwin->w_height != 0
+ && curwin->w_cursor.lnum == curwin->w_topline
+ && width > 0
+#ifdef FEAT_VERTSPLIT
+ && curwin->w_width != 0
+#endif
+ )
+ {
+ /* Cursor past end of screen. Happens with a single line that does
+ * not fit on screen. Find a skipcol to show the text around the
+ * cursor. Avoid scrolling all the time. compute value of "extra":
+ * 1: Less than "p_so" lines above
+ * 2: Less than "p_so" lines below
+ * 3: both of them */
+ extra = 0;
+ if (curwin->w_skipcol + p_so * width > curwin->w_virtcol)
+ extra = 1;
+ /* Compute last display line of the buffer line that we want at the
+ * bottom of the window. */
+ if (p_lines == 0)
+ p_lines = plines_win(curwin, curwin->w_cursor.lnum, FALSE);
+ --p_lines;
+ if (p_lines > curwin->w_wrow + p_so)
+ n = curwin->w_wrow + p_so;
+ else
+ n = p_lines;
+ if ((colnr_T)n >= curwin->w_height + curwin->w_skipcol / width)
+ extra += 2;
+
+ if (extra == 3 || p_lines < p_so * 2)
+ {
+ /* not enough room for 'scrolloff', put cursor in the middle */
+ n = curwin->w_virtcol / width;
+ if (n > curwin->w_height / 2)
+ n -= curwin->w_height / 2;
+ else
+ n = 0;
+ /* don't skip more than necessary */
+ if (n > p_lines - curwin->w_height + 1)
+ n = p_lines - curwin->w_height + 1;
+ curwin->w_skipcol = n * width;
+ }
+ else if (extra == 1)
+ {
+ /* less then 'scrolloff' lines above, decrease skipcol */
+ extra = (curwin->w_skipcol + p_so * width - curwin->w_virtcol
+ + width - 1) / width;
+ if (extra > 0)
+ {
+ if ((colnr_T)(extra * width) > curwin->w_skipcol)
+ extra = curwin->w_skipcol / width;
+ curwin->w_skipcol -= extra * width;
+ }
+ }
+ else if (extra == 2)
+ {
+ /* less then 'scrolloff' lines below, increase skipcol */
+ endcol = (n - curwin->w_height + 1) * width;
+ while (endcol > curwin->w_virtcol)
+ endcol -= width;
+ if (endcol > curwin->w_skipcol)
+ curwin->w_skipcol = endcol;
+ }
+
+ curwin->w_wrow -= curwin->w_skipcol / width;
+ if (curwin->w_wrow >= curwin->w_height)
+ {
+ /* small window, make sure cursor is in it */
+ extra = curwin->w_wrow - curwin->w_height + 1;
+ curwin->w_skipcol += extra * width;
+ curwin->w_wrow -= extra;
+ }
+
+ extra = ((int)prev_skipcol - (int)curwin->w_skipcol) / width;
+ if (extra > 0)
+ win_ins_lines(curwin, 0, extra, FALSE, FALSE);
+ else if (extra < 0)
+ win_del_lines(curwin, 0, -extra, FALSE, FALSE);
+ }
+ else
+ curwin->w_skipcol = 0;
+ if (prev_skipcol != curwin->w_skipcol)
+ redraw_later(NOT_VALID);
+
+ /* Redraw when w_row changes and 'relativenumber' is set */
+ if (((curwin->w_valid & VALID_WROW) == 0 && (curwin->w_p_rnu
+#ifdef FEAT_SYN_HL
+ /* or when w_row changes and 'cursorline' is set. */
+ || curwin->w_p_cul
+#endif
+ ))
+#ifdef FEAT_SYN_HL
+ /* or when w_virtcol changes and 'cursorcolumn' is set */
+ || (curwin->w_p_cuc && (curwin->w_valid & VALID_VIRTCOL) == 0)
+#endif
+ )
+# ifdef FEAT_INS_EXPAND
+ if (!pum_visible())
+# endif
+ redraw_later(SOME_VALID);
+
+ curwin->w_valid |= VALID_WCOL|VALID_WROW|VALID_VIRTCOL;
+}
+
+/*
+ * Scroll the current window down by "line_count" logical lines. "CTRL-Y"
+ */
+ void
+scrolldown(line_count, byfold)
+ long line_count;
+ int byfold UNUSED; /* TRUE: count a closed fold as one line */
+{
+ long done = 0; /* total # of physical lines done */
+ int wrow;
+ int moved = FALSE;
+
+#ifdef FEAT_FOLDING
+ linenr_T first;
+
+ /* Make sure w_topline is at the first of a sequence of folded lines. */
+ (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
+#endif
+ validate_cursor(); /* w_wrow needs to be valid */
+ while (line_count-- > 0)
+ {
+#ifdef FEAT_DIFF
+ if (curwin->w_topfill < diff_check(curwin, curwin->w_topline)
+ && curwin->w_topfill < curwin->w_height - 1)
+ {
+ ++curwin->w_topfill;
+ ++done;
+ }
+ else
+#endif
+ {
+ if (curwin->w_topline == 1)
+ break;
+ --curwin->w_topline;
+#ifdef FEAT_DIFF
+ curwin->w_topfill = 0;
+#endif
+#ifdef FEAT_FOLDING
+ /* A sequence of folded lines only counts for one logical line */
+ if (hasFolding(curwin->w_topline, &first, NULL))
+ {
+ ++done;
+ if (!byfold)
+ line_count -= curwin->w_topline - first - 1;
+ curwin->w_botline -= curwin->w_topline - first;
+ curwin->w_topline = first;
+ }
+ else
+#endif
+#ifdef FEAT_DIFF
+ done += plines_nofill(curwin->w_topline);
+#else
+ done += plines(curwin->w_topline);
+#endif
+ }
+ --curwin->w_botline; /* approximate w_botline */
+ invalidate_botline();
+ }
+ curwin->w_wrow += done; /* keep w_wrow updated */
+ curwin->w_cline_row += done; /* keep w_cline_row updated */
+
+#ifdef FEAT_DIFF
+ if (curwin->w_cursor.lnum == curwin->w_topline)
+ curwin->w_cline_row = 0;
+ check_topfill(curwin, TRUE);
+#endif
+
+ /*
+ * Compute the row number of the last row of the cursor line
+ * and move the cursor onto the displayed part of the window.
+ */
+ wrow = curwin->w_wrow;
+ if (curwin->w_p_wrap
+#ifdef FEAT_VERTSPLIT
+ && curwin->w_width != 0
+#endif
+ )
+ {
+ validate_virtcol();
+ validate_cheight();
+ wrow += curwin->w_cline_height - 1 -
+ curwin->w_virtcol / W_WIDTH(curwin);
+ }
+ while (wrow >= curwin->w_height && curwin->w_cursor.lnum > 1)
+ {
+#ifdef FEAT_FOLDING
+ if (hasFolding(curwin->w_cursor.lnum, &first, NULL))
+ {
+ --wrow;
+ if (first == 1)
+ curwin->w_cursor.lnum = 1;
+ else
+ curwin->w_cursor.lnum = first - 1;
+ }
+ else
+#endif
+ wrow -= plines(curwin->w_cursor.lnum--);
+ curwin->w_valid &=
+ ~(VALID_WROW|VALID_WCOL|VALID_CHEIGHT|VALID_CROW|VALID_VIRTCOL);
+ moved = TRUE;
+ }
+ if (moved)
+ {
+#ifdef FEAT_FOLDING
+ /* Move cursor to first line of closed fold. */
+ foldAdjustCursor();
+#endif
+ coladvance(curwin->w_curswant);
+ }
+}
+
+/*
+ * Scroll the current window up by "line_count" logical lines. "CTRL-E"
+ */
+ void
+scrollup(line_count, byfold)
+ long line_count;
+ int byfold UNUSED; /* TRUE: count a closed fold as one line */
+{
+#if defined(FEAT_FOLDING) || defined(FEAT_DIFF)
+ linenr_T lnum;
+
+ if (
+# ifdef FEAT_FOLDING
+ (byfold && hasAnyFolding(curwin))
+# ifdef FEAT_DIFF
+ ||
+# endif
+# endif
+# ifdef FEAT_DIFF
+ curwin->w_p_diff
+# endif
+ )
+ {
+ /* count each sequence of folded lines as one logical line */
+ lnum = curwin->w_topline;
+ while (line_count--)
+ {
+# ifdef FEAT_DIFF
+ if (curwin->w_topfill > 0)
+ --curwin->w_topfill;
+ else
+# endif
+ {
+# ifdef FEAT_FOLDING
+ if (byfold)
+ (void)hasFolding(lnum, NULL, &lnum);
+# endif
+ if (lnum >= curbuf->b_ml.ml_line_count)
+ break;
+ ++lnum;
+# ifdef FEAT_DIFF
+ curwin->w_topfill = diff_check_fill(curwin, lnum);
+# endif
+ }
+ }
+ /* approximate w_botline */
+ curwin->w_botline += lnum - curwin->w_topline;
+ curwin->w_topline = lnum;
+ }
+ else
+#endif
+ {
+ curwin->w_topline += line_count;
+ curwin->w_botline += line_count; /* approximate w_botline */
+ }
+
+ if (curwin->w_topline > curbuf->b_ml.ml_line_count)
+ curwin->w_topline = curbuf->b_ml.ml_line_count;
+ if (curwin->w_botline > curbuf->b_ml.ml_line_count + 1)
+ curwin->w_botline = curbuf->b_ml.ml_line_count + 1;
+
+#ifdef FEAT_DIFF
+ check_topfill(curwin, FALSE);
+#endif
+
+#ifdef FEAT_FOLDING
+ if (hasAnyFolding(curwin))
+ /* Make sure w_topline is at the first of a sequence of folded lines. */
+ (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
+#endif
+
+ curwin->w_valid &= ~(VALID_WROW|VALID_CROW|VALID_BOTLINE);
+ if (curwin->w_cursor.lnum < curwin->w_topline)
+ {
+ curwin->w_cursor.lnum = curwin->w_topline;
+ curwin->w_valid &=
+ ~(VALID_WROW|VALID_WCOL|VALID_CHEIGHT|VALID_CROW|VALID_VIRTCOL);
+ coladvance(curwin->w_curswant);
+ }
+}
+
+#ifdef FEAT_DIFF
+/*
+ * Don't end up with too many filler lines in the window.
+ */
+ void
+check_topfill(wp, down)
+ win_T *wp;
+ int down; /* when TRUE scroll down when not enough space */
+{
+ int n;
+
+ if (wp->w_topfill > 0)
+ {
+ n = plines_win_nofill(wp, wp->w_topline, TRUE);
+ if (wp->w_topfill + n > wp->w_height)
+ {
+ if (down && wp->w_topline > 1)
+ {
+ --wp->w_topline;
+ wp->w_topfill = 0;
+ }
+ else
+ {
+ wp->w_topfill = wp->w_height - n;
+ if (wp->w_topfill < 0)
+ wp->w_topfill = 0;
+ }
+ }
+ }
+}
+
+/*
+ * Use as many filler lines as possible for w_topline. Make sure w_topline
+ * is still visible.
+ */
+ static void
+max_topfill()
+{
+ int n;
+
+ n = plines_nofill(curwin->w_topline);
+ if (n >= curwin->w_height)
+ curwin->w_topfill = 0;
+ else
+ {
+ curwin->w_topfill = diff_check_fill(curwin, curwin->w_topline);
+ if (curwin->w_topfill + n > curwin->w_height)
+ curwin->w_topfill = curwin->w_height - n;
+ }
+}
+#endif
+
+#if defined(FEAT_INS_EXPAND) || defined(PROTO)
+/*
+ * Scroll the screen one line down, but don't do it if it would move the
+ * cursor off the screen.
+ */
+ void
+scrolldown_clamp()
+{
+ int end_row;
+#ifdef FEAT_DIFF
+ int can_fill = (curwin->w_topfill
+ < diff_check_fill(curwin, curwin->w_topline));
+#endif
+
+ if (curwin->w_topline <= 1
+#ifdef FEAT_DIFF
+ && !can_fill
+#endif
+ )
+ return;
+
+ validate_cursor(); /* w_wrow needs to be valid */
+
+ /*
+ * Compute the row number of the last row of the cursor line
+ * and make sure it doesn't go off the screen. Make sure the cursor
+ * doesn't go past 'scrolloff' lines from the screen end.
+ */
+ end_row = curwin->w_wrow;
+#ifdef FEAT_DIFF
+ if (can_fill)
+ ++end_row;
+ else
+ end_row += plines_nofill(curwin->w_topline - 1);
+#else
+ end_row += plines(curwin->w_topline - 1);
+#endif
+ if (curwin->w_p_wrap
+#ifdef FEAT_VERTSPLIT
+ && curwin->w_width != 0
+#endif
+ )
+ {
+ validate_cheight();
+ validate_virtcol();
+ end_row += curwin->w_cline_height - 1 -
+ curwin->w_virtcol / W_WIDTH(curwin);
+ }
+ if (end_row < curwin->w_height - p_so)
+ {
+#ifdef FEAT_DIFF
+ if (can_fill)
+ {
+ ++curwin->w_topfill;
+ check_topfill(curwin, TRUE);
+ }
+ else
+ {
+ --curwin->w_topline;
+ curwin->w_topfill = 0;
+ }
+#else
+ --curwin->w_topline;
+#endif
+#ifdef FEAT_FOLDING
+ hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
+#endif
+ --curwin->w_botline; /* approximate w_botline */
+ curwin->w_valid &= ~(VALID_WROW|VALID_CROW|VALID_BOTLINE);
+ }
+}
+
+/*
+ * Scroll the screen one line up, but don't do it if it would move the cursor
+ * off the screen.
+ */
+ void
+scrollup_clamp()
+{
+ int start_row;
+
+ if (curwin->w_topline == curbuf->b_ml.ml_line_count
+#ifdef FEAT_DIFF
+ && curwin->w_topfill == 0
+#endif
+ )
+ return;
+
+ validate_cursor(); /* w_wrow needs to be valid */
+
+ /*
+ * Compute the row number of the first row of the cursor line
+ * and make sure it doesn't go off the screen. Make sure the cursor
+ * doesn't go before 'scrolloff' lines from the screen start.
+ */
+#ifdef FEAT_DIFF
+ start_row = curwin->w_wrow - plines_nofill(curwin->w_topline)
+ - curwin->w_topfill;
+#else
+ start_row = curwin->w_wrow - plines(curwin->w_topline);
+#endif
+ if (curwin->w_p_wrap
+#ifdef FEAT_VERTSPLIT
+ && curwin->w_width != 0
+#endif
+ )
+ {
+ validate_virtcol();
+ start_row -= curwin->w_virtcol / W_WIDTH(curwin);
+ }
+ if (start_row >= p_so)
+ {
+#ifdef FEAT_DIFF
+ if (curwin->w_topfill > 0)
+ --curwin->w_topfill;
+ else
+#endif
+ {
+#ifdef FEAT_FOLDING
+ (void)hasFolding(curwin->w_topline, NULL, &curwin->w_topline);
+#endif
+ ++curwin->w_topline;
+ }
+ ++curwin->w_botline; /* approximate w_botline */
+ curwin->w_valid &= ~(VALID_WROW|VALID_CROW|VALID_BOTLINE);
+ }
+}
+#endif /* FEAT_INS_EXPAND */
+
+/*
+ * Add one line above "lp->lnum". This can be a filler line, a closed fold or
+ * a (wrapped) text line. Uses and sets "lp->fill".
+ * Returns the height of the added line in "lp->height".
+ * Lines above the first one are incredibly high: MAXCOL.
+ */
+ static void
+topline_back(lp)
+ lineoff_T *lp;
+{
+#ifdef FEAT_DIFF
+ if (lp->fill < diff_check_fill(curwin, lp->lnum))
+ {
+ /* Add a filler line. */
+ ++lp->fill;
+ lp->height = 1;
+ }
+ else
+#endif
+ {
+ --lp->lnum;
+#ifdef FEAT_DIFF
+ lp->fill = 0;
+#endif
+ if (lp->lnum < 1)
+ lp->height = MAXCOL;
+ else
+#ifdef FEAT_FOLDING
+ if (hasFolding(lp->lnum, &lp->lnum, NULL))
+ /* Add a closed fold */
+ lp->height = 1;
+ else
+#endif
+ {
+#ifdef FEAT_DIFF
+ lp->height = plines_nofill(lp->lnum);
+#else
+ lp->height = plines(lp->lnum);
+#endif
+ }
+ }
+}
+
+/*
+ * Add one line below "lp->lnum". This can be a filler line, a closed fold or
+ * a (wrapped) text line. Uses and sets "lp->fill".
+ * Returns the height of the added line in "lp->height".
+ * Lines below the last one are incredibly high.
+ */
+ static void
+botline_forw(lp)
+ lineoff_T *lp;
+{
+#ifdef FEAT_DIFF
+ if (lp->fill < diff_check_fill(curwin, lp->lnum + 1))
+ {
+ /* Add a filler line. */
+ ++lp->fill;
+ lp->height = 1;
+ }
+ else
+#endif
+ {
+ ++lp->lnum;
+#ifdef FEAT_DIFF
+ lp->fill = 0;
+#endif
+ if (lp->lnum > curbuf->b_ml.ml_line_count)
+ lp->height = MAXCOL;
+ else
+#ifdef FEAT_FOLDING
+ if (hasFolding(lp->lnum, NULL, &lp->lnum))
+ /* Add a closed fold */
+ lp->height = 1;
+ else
+#endif
+ {
+#ifdef FEAT_DIFF
+ lp->height = plines_nofill(lp->lnum);
+#else
+ lp->height = plines(lp->lnum);
+#endif
+ }
+ }
+}
+
+#ifdef FEAT_DIFF
+/*
+ * Switch from including filler lines below lp->lnum to including filler
+ * lines above loff.lnum + 1. This keeps pointing to the same line.
+ * When there are no filler lines nothing changes.
+ */
+ static void
+botline_topline(lp)
+ lineoff_T *lp;
+{
+ if (lp->fill > 0)
+ {
+ ++lp->lnum;
+ lp->fill = diff_check_fill(curwin, lp->lnum) - lp->fill + 1;
+ }
+}
+
+/*
+ * Switch from including filler lines above lp->lnum to including filler
+ * lines below loff.lnum - 1. This keeps pointing to the same line.
+ * When there are no filler lines nothing changes.
+ */
+ static void
+topline_botline(lp)
+ lineoff_T *lp;
+{
+ if (lp->fill > 0)
+ {
+ lp->fill = diff_check_fill(curwin, lp->lnum) - lp->fill + 1;
+ --lp->lnum;
+ }
+}
+#endif
+
+/*
+ * Recompute topline to put the cursor at the top of the window.
+ * Scroll at least "min_scroll" lines.
+ * If "always" is TRUE, always set topline (for "zt").
+ */
+ void
+scroll_cursor_top(min_scroll, always)
+ int min_scroll;
+ int always;
+{
+ int scrolled = 0;
+ int extra = 0;
+ int used;
+ int i;
+ linenr_T top; /* just above displayed lines */
+ linenr_T bot; /* just below displayed lines */
+ linenr_T old_topline = curwin->w_topline;
+#ifdef FEAT_DIFF
+ linenr_T old_topfill = curwin->w_topfill;
+#endif
+ linenr_T new_topline;
+ int off = p_so;
+
+#ifdef FEAT_MOUSE
+ if (mouse_dragging > 0)
+ off = mouse_dragging - 1;
+#endif
+
+ /*
+ * Decrease topline until:
+ * - it has become 1
+ * - (part of) the cursor line is moved off the screen or
+ * - moved at least 'scrolljump' lines and
+ * - at least 'scrolloff' lines above and below the cursor
+ */
+ validate_cheight();
+ used = curwin->w_cline_height;
+ if (curwin->w_cursor.lnum < curwin->w_topline)
+ scrolled = used;
+
+#ifdef FEAT_FOLDING
+ if (hasFolding(curwin->w_cursor.lnum, &top, &bot))
+ {
+ --top;
+ ++bot;
+ }
+ else
+#endif
+ {
+ top = curwin->w_cursor.lnum - 1;
+ bot = curwin->w_cursor.lnum + 1;
+ }
+ new_topline = top + 1;
+
+#ifdef FEAT_DIFF
+ /* count filler lines of the cursor window as context */
+ i = diff_check_fill(curwin, curwin->w_cursor.lnum);
+ used += i;
+ extra += i;
+#endif
+
+ /*
+ * Check if the lines from "top" to "bot" fit in the window. If they do,
+ * set new_topline and advance "top" and "bot" to include more lines.
+ */
+ while (top > 0)
+ {
+#ifdef FEAT_FOLDING
+ if (hasFolding(top, &top, NULL))
+ /* count one logical line for a sequence of folded lines */
+ i = 1;
+ else
+#endif
+ i = plines(top);
+ used += i;
+ if (extra + i <= off && bot < curbuf->b_ml.ml_line_count)
+ {
+#ifdef FEAT_FOLDING
+ if (hasFolding(bot, NULL, &bot))
+ /* count one logical line for a sequence of folded lines */
+ ++used;
+ else
+#endif
+ used += plines(bot);
+ }
+ if (used > curwin->w_height)
+ break;
+ if (top < curwin->w_topline)
+ scrolled += i;
+
+ /*
+ * If scrolling is needed, scroll at least 'sj' lines.
+ */
+ if ((new_topline >= curwin->w_topline || scrolled > min_scroll)
+ && extra >= off)
+ break;
+
+ extra += i;
+ new_topline = top;
+ --top;
+ ++bot;
+ }
+
+ /*
+ * If we don't have enough space, put cursor in the middle.
+ * This makes sure we get the same position when using "k" and "j"
+ * in a small window.
+ */
+ if (used > curwin->w_height)
+ scroll_cursor_halfway(FALSE);
+ else
+ {
+ /*
+ * If "always" is FALSE, only adjust topline to a lower value, higher
+ * value may happen with wrapping lines
+ */
+ if (new_topline < curwin->w_topline || always)
+ curwin->w_topline = new_topline;
+ if (curwin->w_topline > curwin->w_cursor.lnum)
+ curwin->w_topline = curwin->w_cursor.lnum;
+#ifdef FEAT_DIFF
+ curwin->w_topfill = diff_check_fill(curwin, curwin->w_topline);
+ if (curwin->w_topfill > 0 && extra > off)
+ {
+ curwin->w_topfill -= extra - off;
+ if (curwin->w_topfill < 0)
+ curwin->w_topfill = 0;
+ }
+ check_topfill(curwin, FALSE);
+#endif
+ if (curwin->w_topline != old_topline
+#ifdef FEAT_DIFF
+ || curwin->w_topfill != old_topfill
+#endif
+ )
+ curwin->w_valid &=
+ ~(VALID_WROW|VALID_CROW|VALID_BOTLINE|VALID_BOTLINE_AP);
+ curwin->w_valid |= VALID_TOPLINE;
+ }
+}
+
+/*
+ * Set w_empty_rows and w_filler_rows for window "wp", having used up "used"
+ * screen lines for text lines.
+ */
+ void
+set_empty_rows(wp, used)
+ win_T *wp;
+ int used;
+{
+#ifdef FEAT_DIFF
+ wp->w_filler_rows = 0;
+#endif
+ if (used == 0)
+ wp->w_empty_rows = 0; /* single line that doesn't fit */
+ else
+ {
+ wp->w_empty_rows = wp->w_height - used;
+#ifdef FEAT_DIFF
+ if (wp->w_botline <= wp->w_buffer->b_ml.ml_line_count)
+ {
+ wp->w_filler_rows = diff_check_fill(wp, wp->w_botline);
+ if (wp->w_empty_rows > wp->w_filler_rows)
+ wp->w_empty_rows -= wp->w_filler_rows;
+ else
+ {
+ wp->w_filler_rows = wp->w_empty_rows;
+ wp->w_empty_rows = 0;
+ }
+ }
+#endif
+ }
+}
+
+/*
+ * Recompute topline to put the cursor at the bottom of the window.
+ * Scroll at least "min_scroll" lines.
+ * If "set_topbot" is TRUE, set topline and botline first (for "zb").
+ * This is messy stuff!!!
+ */
+ void
+scroll_cursor_bot(min_scroll, set_topbot)
+ int min_scroll;
+ int set_topbot;
+{
+ int used;
+ int scrolled = 0;
+ int extra = 0;
+ int i;
+ linenr_T line_count;
+ linenr_T old_topline = curwin->w_topline;
+ lineoff_T loff;
+ lineoff_T boff;
+#ifdef FEAT_DIFF
+ int old_topfill = curwin->w_topfill;
+ int fill_below_window;
+#endif
+ linenr_T old_botline = curwin->w_botline;
+ linenr_T old_valid = curwin->w_valid;
+ int old_empty_rows = curwin->w_empty_rows;
+ linenr_T cln; /* Cursor Line Number */
+
+ cln = curwin->w_cursor.lnum;
+ if (set_topbot)
+ {
+ used = 0;
+ curwin->w_botline = cln + 1;
+#ifdef FEAT_DIFF
+ loff.fill = 0;
+#endif
+ for (curwin->w_topline = curwin->w_botline;
+ curwin->w_topline > 1;
+ curwin->w_topline = loff.lnum)
+ {
+ loff.lnum = curwin->w_topline;
+ topline_back(&loff);
+ if (loff.height == MAXCOL || used + loff.height > curwin->w_height)
+ break;
+ used += loff.height;
+#ifdef FEAT_DIFF
+ curwin->w_topfill = loff.fill;
+#endif
+ }
+ set_empty_rows(curwin, used);
+ curwin->w_valid |= VALID_BOTLINE|VALID_BOTLINE_AP;
+ if (curwin->w_topline != old_topline
+#ifdef FEAT_DIFF
+ || curwin->w_topfill != old_topfill
+#endif
+ )
+ curwin->w_valid &= ~(VALID_WROW|VALID_CROW);
+ }
+ else
+ validate_botline();
+
+ /* The lines of the cursor line itself are always used. */
+#ifdef FEAT_DIFF
+ used = plines_nofill(cln);
+#else
+ validate_cheight();
+ used = curwin->w_cline_height;
+#endif
+
+ /* If the cursor is below botline, we will at least scroll by the height
+ * of the cursor line. Correct for empty lines, which are really part of
+ * botline. */
+ if (cln >= curwin->w_botline)
+ {
+ scrolled = used;
+ if (cln == curwin->w_botline)
+ scrolled -= curwin->w_empty_rows;
+ }
+
+ /*
+ * Stop counting lines to scroll when
+ * - hitting start of the file
+ * - scrolled nothing or at least 'sj' lines
+ * - at least 'so' lines below the cursor
+ * - lines between botline and cursor have been counted
+ */
+#ifdef FEAT_FOLDING
+ if (!hasFolding(curwin->w_cursor.lnum, &loff.lnum, &boff.lnum))
+#endif
+ {
+ loff.lnum = cln;
+ boff.lnum = cln;
+ }
+#ifdef FEAT_DIFF
+ loff.fill = 0;
+ boff.fill = 0;
+ fill_below_window = diff_check_fill(curwin, curwin->w_botline)
+ - curwin->w_filler_rows;
+#endif
+
+ while (loff.lnum > 1)
+ {
+ /* Stop when scrolled nothing or at least "min_scroll", found "extra"
+ * context for 'scrolloff' and counted all lines below the window. */
+ if ((((scrolled <= 0 || scrolled >= min_scroll)
+ && extra >= (
+#ifdef FEAT_MOUSE
+ mouse_dragging > 0 ? mouse_dragging - 1 :
+#endif
+ p_so))
+ || boff.lnum + 1 > curbuf->b_ml.ml_line_count)
+ && loff.lnum <= curwin->w_botline
+#ifdef FEAT_DIFF
+ && (loff.lnum < curwin->w_botline
+ || loff.fill >= fill_below_window)
+#endif
+ )
+ break;
+
+ /* Add one line above */
+ topline_back(&loff);
+ if (loff.height == MAXCOL)
+ used = MAXCOL;
+ else
+ used += loff.height;
+ if (used > curwin->w_height)
+ break;
+ if (loff.lnum >= curwin->w_botline
+#ifdef FEAT_DIFF
+ && (loff.lnum > curwin->w_botline
+ || loff.fill <= fill_below_window)
+#endif
+ )
+ {
+ /* Count screen lines that are below the window. */
+ scrolled += loff.height;
+ if (loff.lnum == curwin->w_botline
+#ifdef FEAT_DIFF
+ && boff.fill == 0
+#endif
+ )
+ scrolled -= curwin->w_empty_rows;
+ }
+
+ if (boff.lnum < curbuf->b_ml.ml_line_count)
+ {
+ /* Add one line below */
+ botline_forw(&boff);
+ used += boff.height;
+ if (used > curwin->w_height)
+ break;
+ if (extra < (
+#ifdef FEAT_MOUSE
+ mouse_dragging > 0 ? mouse_dragging - 1 :
+#endif
+ p_so) || scrolled < min_scroll)
+ {
+ extra += boff.height;
+ if (boff.lnum >= curwin->w_botline
+#ifdef FEAT_DIFF
+ || (boff.lnum + 1 == curwin->w_botline
+ && boff.fill > curwin->w_filler_rows)
+#endif
+ )
+ {
+ /* Count screen lines that are below the window. */
+ scrolled += boff.height;
+ if (boff.lnum == curwin->w_botline
+#ifdef FEAT_DIFF
+ && boff.fill == 0
+#endif
+ )
+ scrolled -= curwin->w_empty_rows;
+ }
+ }
+ }
+ }
+
+ /* curwin->w_empty_rows is larger, no need to scroll */
+ if (scrolled <= 0)
+ line_count = 0;
+ /* more than a screenfull, don't scroll but redraw */
+ else if (used > curwin->w_height)
+ line_count = used;
+ /* scroll minimal number of lines */
+ else
+ {
+ line_count = 0;
+#ifdef FEAT_DIFF
+ boff.fill = curwin->w_topfill;
+#endif
+ boff.lnum = curwin->w_topline - 1;
+ for (i = 0; i < scrolled && boff.lnum < curwin->w_botline; )
+ {
+ botline_forw(&boff);
+ i += boff.height;
+ ++line_count;
+ }
+ if (i < scrolled) /* below curwin->w_botline, don't scroll */
+ line_count = 9999;
+ }
+
+ /*
+ * Scroll up if the cursor is off the bottom of the screen a bit.
+ * Otherwise put it at 1/2 of the screen.
+ */
+ if (line_count >= curwin->w_height && line_count > min_scroll)
+ scroll_cursor_halfway(FALSE);
+ else
+ scrollup(line_count, TRUE);
+
+ /*
+ * If topline didn't change we need to restore w_botline and w_empty_rows
+ * (we changed them).
+ * If topline did change, update_screen() will set botline.
+ */
+ if (curwin->w_topline == old_topline && set_topbot)
+ {
+ curwin->w_botline = old_botline;
+ curwin->w_empty_rows = old_empty_rows;
+ curwin->w_valid = old_valid;
+ }
+ curwin->w_valid |= VALID_TOPLINE;
+}
+
+/*
+ * Recompute topline to put the cursor halfway the window
+ * If "atend" is TRUE, also put it halfway at the end of the file.
+ */
+ void
+scroll_cursor_halfway(atend)
+ int atend;
+{
+ int above = 0;
+ linenr_T topline;
+#ifdef FEAT_DIFF
+ int topfill = 0;
+#endif
+ int below = 0;
+ int used;
+ lineoff_T loff;
+ lineoff_T boff;
+
+ loff.lnum = boff.lnum = curwin->w_cursor.lnum;
+#ifdef FEAT_FOLDING
+ (void)hasFolding(loff.lnum, &loff.lnum, &boff.lnum);
+#endif
+#ifdef FEAT_DIFF
+ used = plines_nofill(loff.lnum);
+ loff.fill = 0;
+ boff.fill = 0;
+#else
+ used = plines(loff.lnum);
+#endif
+ topline = loff.lnum;
+ while (topline > 1)
+ {
+ if (below <= above) /* add a line below the cursor first */
+ {
+ if (boff.lnum < curbuf->b_ml.ml_line_count)
+ {
+ botline_forw(&boff);
+ used += boff.height;
+ if (used > curwin->w_height)
+ break;
+ below += boff.height;
+ }
+ else
+ {
+ ++below; /* count a "~" line */
+ if (atend)
+ ++used;
+ }
+ }
+
+ if (below > above) /* add a line above the cursor */
+ {
+ topline_back(&loff);
+ if (loff.height == MAXCOL)
+ used = MAXCOL;
+ else
+ used += loff.height;
+ if (used > curwin->w_height)
+ break;
+ above += loff.height;
+ topline = loff.lnum;
+#ifdef FEAT_DIFF
+ topfill = loff.fill;
+#endif
+ }
+ }
+#ifdef FEAT_FOLDING
+ if (!hasFolding(topline, &curwin->w_topline, NULL))
+#endif
+ curwin->w_topline = topline;
+#ifdef FEAT_DIFF
+ curwin->w_topfill = topfill;
+ check_topfill(curwin, FALSE);
+#endif
+ curwin->w_valid &= ~(VALID_WROW|VALID_CROW|VALID_BOTLINE|VALID_BOTLINE_AP);
+ curwin->w_valid |= VALID_TOPLINE;
+}
+
+/*
+ * Correct the cursor position so that it is in a part of the screen at least
+ * 'so' lines from the top and bottom, if possible.
+ * If not possible, put it at the same position as scroll_cursor_halfway().
+ * When called topline must be valid!
+ */
+ void
+cursor_correct()
+{
+ int above = 0; /* screen lines above topline */
+ linenr_T topline;
+ int below = 0; /* screen lines below botline */
+ linenr_T botline;
+ int above_wanted, below_wanted;
+ linenr_T cln; /* Cursor Line Number */
+ int max_off;
+
+ /*
+ * How many lines we would like to have above/below the cursor depends on
+ * whether the first/last line of the file is on screen.
+ */
+ above_wanted = p_so;
+ below_wanted = p_so;
+#ifdef FEAT_MOUSE
+ if (mouse_dragging > 0)
+ {
+ above_wanted = mouse_dragging - 1;
+ below_wanted = mouse_dragging - 1;
+ }
+#endif
+ if (curwin->w_topline == 1)
+ {
+ above_wanted = 0;
+ max_off = curwin->w_height / 2;
+ if (below_wanted > max_off)
+ below_wanted = max_off;
+ }
+ validate_botline();
+ if (curwin->w_botline == curbuf->b_ml.ml_line_count + 1
+#ifdef FEAT_MOUSE
+ && mouse_dragging == 0
+#endif
+ )
+ {
+ below_wanted = 0;
+ max_off = (curwin->w_height - 1) / 2;
+ if (above_wanted > max_off)
+ above_wanted = max_off;
+ }
+
+ /*
+ * If there are sufficient file-lines above and below the cursor, we can
+ * return now.
+ */
+ cln = curwin->w_cursor.lnum;
+ if (cln >= curwin->w_topline + above_wanted
+ && cln < curwin->w_botline - below_wanted
+#ifdef FEAT_FOLDING
+ && !hasAnyFolding(curwin)
+#endif
+ )
+ return;
+
+ /*
+ * Narrow down the area where the cursor can be put by taking lines from
+ * the top and the bottom until:
+ * - the desired context lines are found
+ * - the lines from the top is past the lines from the bottom
+ */
+ topline = curwin->w_topline;
+ botline = curwin->w_botline - 1;
+#ifdef FEAT_DIFF
+ /* count filler lines as context */
+ above = curwin->w_topfill;
+ below = curwin->w_filler_rows;
+#endif
+ while ((above < above_wanted || below < below_wanted) && topline < botline)
+ {
+ if (below < below_wanted && (below <= above || above >= above_wanted))
+ {
+#ifdef FEAT_FOLDING
+ if (hasFolding(botline, &botline, NULL))
+ ++below;
+ else
+#endif
+ below += plines(botline);
+ --botline;
+ }
+ if (above < above_wanted && (above < below || below >= below_wanted))
+ {
+#ifdef FEAT_FOLDING
+ if (hasFolding(topline, NULL, &topline))
+ ++above;
+ else
+#endif
+#ifndef FEAT_DIFF
+ above += plines(topline);
+#else
+ above += plines_nofill(topline);
+
+ /* Count filler lines below this line as context. */
+ if (topline < botline)
+ above += diff_check_fill(curwin, topline + 1);
+#endif
+ ++topline;
+ }
+ }
+ if (topline == botline || botline == 0)
+ curwin->w_cursor.lnum = topline;
+ else if (topline > botline)
+ curwin->w_cursor.lnum = botline;
+ else
+ {
+ if (cln < topline && curwin->w_topline > 1)
+ {
+ curwin->w_cursor.lnum = topline;
+ curwin->w_valid &=
+ ~(VALID_WROW|VALID_WCOL|VALID_CHEIGHT|VALID_CROW);
+ }
+ if (cln > botline && curwin->w_botline <= curbuf->b_ml.ml_line_count)
+ {
+ curwin->w_cursor.lnum = botline;
+ curwin->w_valid &=
+ ~(VALID_WROW|VALID_WCOL|VALID_CHEIGHT|VALID_CROW);
+ }
+ }
+ curwin->w_valid |= VALID_TOPLINE;
+}
+
+static void get_scroll_overlap __ARGS((lineoff_T *lp, int dir));
+
+/*
+ * move screen 'count' pages up or down and update screen
+ *
+ * return FAIL for failure, OK otherwise
+ */
+ int
+onepage(dir, count)
+ int dir;
+ long count;
+{
+ long n;
+ int retval = OK;
+ lineoff_T loff;
+ linenr_T old_topline = curwin->w_topline;
+
+ if (curbuf->b_ml.ml_line_count == 1) /* nothing to do */
+ {
+ beep_flush();
+ return FAIL;
+ }
+
+ for ( ; count > 0; --count)
+ {
+ validate_botline();
+ /*
+ * It's an error to move a page up when the first line is already on
+ * the screen. It's an error to move a page down when the last line
+ * is on the screen and the topline is 'scrolloff' lines from the
+ * last line.
+ */
+ if (dir == FORWARD
+ ? ((curwin->w_topline >= curbuf->b_ml.ml_line_count - p_so)
+ && curwin->w_botline > curbuf->b_ml.ml_line_count)
+ : (curwin->w_topline == 1
+#ifdef FEAT_DIFF
+ && curwin->w_topfill ==
+ diff_check_fill(curwin, curwin->w_topline)
+#endif
+ ))
+ {
+ beep_flush();
+ retval = FAIL;
+ break;
+ }
+
+#ifdef FEAT_DIFF
+ loff.fill = 0;
+#endif
+ if (dir == FORWARD)
+ {
+ if (firstwin == lastwin && p_window > 0 && p_window < Rows - 1)
+ {
+ /* Vi compatible scrolling */
+ if (p_window <= 2)
+ ++curwin->w_topline;
+ else
+ curwin->w_topline += p_window - 2;
+ if (curwin->w_topline > curbuf->b_ml.ml_line_count)
+ curwin->w_topline = curbuf->b_ml.ml_line_count;
+ curwin->w_cursor.lnum = curwin->w_topline;
+ }
+ else if (curwin->w_botline > curbuf->b_ml.ml_line_count)
+ {
+ /* at end of file */
+ curwin->w_topline = curbuf->b_ml.ml_line_count;
+#ifdef FEAT_DIFF
+ curwin->w_topfill = 0;
+#endif
+ curwin->w_valid &= ~(VALID_WROW|VALID_CROW);
+ }
+ else
+ {
+ /* For the overlap, start with the line just below the window
+ * and go upwards. */
+ loff.lnum = curwin->w_botline;
+#ifdef FEAT_DIFF
+ loff.fill = diff_check_fill(curwin, loff.lnum)
+ - curwin->w_filler_rows;
+#endif
+ get_scroll_overlap(&loff, -1);
+ curwin->w_topline = loff.lnum;
+#ifdef FEAT_DIFF
+ curwin->w_topfill = loff.fill;
+ check_topfill(curwin, FALSE);
+#endif
+ curwin->w_cursor.lnum = curwin->w_topline;
+ curwin->w_valid &= ~(VALID_WCOL|VALID_CHEIGHT|VALID_WROW|
+ VALID_CROW|VALID_BOTLINE|VALID_BOTLINE_AP);
+ }
+ }
+ else /* dir == BACKWARDS */
+ {
+#ifdef FEAT_DIFF
+ if (curwin->w_topline == 1)
+ {
+ /* Include max number of filler lines */
+ max_topfill();
+ continue;
+ }
+#endif
+ if (firstwin == lastwin && p_window > 0 && p_window < Rows - 1)
+ {
+ /* Vi compatible scrolling (sort of) */
+ if (p_window <= 2)
+ --curwin->w_topline;
+ else
+ curwin->w_topline -= p_window - 2;
+ if (curwin->w_topline < 1)
+ curwin->w_topline = 1;
+ curwin->w_cursor.lnum = curwin->w_topline + p_window - 1;
+ if (curwin->w_cursor.lnum > curbuf->b_ml.ml_line_count)
+ curwin->w_cursor.lnum = curbuf->b_ml.ml_line_count;
+ continue;
+ }
+
+ /* Find the line at the top of the window that is going to be the
+ * line at the bottom of the window. Make sure this results in
+ * the same line as before doing CTRL-F. */
+ loff.lnum = curwin->w_topline - 1;
+#ifdef FEAT_DIFF
+ loff.fill = diff_check_fill(curwin, loff.lnum + 1)
+ - curwin->w_topfill;
+#endif
+ get_scroll_overlap(&loff, 1);
+
+ if (loff.lnum >= curbuf->b_ml.ml_line_count)
+ {
+ loff.lnum = curbuf->b_ml.ml_line_count;
+#ifdef FEAT_DIFF
+ loff.fill = 0;
+ }
+ else
+ {
+ botline_topline(&loff);
+#endif
+ }
+ curwin->w_cursor.lnum = loff.lnum;
+
+ /* Find the line just above the new topline to get the right line
+ * at the bottom of the window. */
+ n = 0;
+ while (n <= curwin->w_height && loff.lnum >= 1)
+ {
+ topline_back(&loff);
+ if (loff.height == MAXCOL)
+ n = MAXCOL;
+ else
+ n += loff.height;
+ }
+ if (loff.lnum < 1) /* at begin of file */
+ {
+ curwin->w_topline = 1;
+#ifdef FEAT_DIFF
+ max_topfill();
+#endif
+ curwin->w_valid &= ~(VALID_WROW|VALID_CROW|VALID_BOTLINE);
+ }
+ else
+ {
+ /* Go two lines forward again. */
+#ifdef FEAT_DIFF
+ topline_botline(&loff);
+#endif
+ botline_forw(&loff);
+ botline_forw(&loff);
+#ifdef FEAT_DIFF
+ botline_topline(&loff);
+#endif
+#ifdef FEAT_FOLDING
+ /* We're at the wrong end of a fold now. */
+ (void)hasFolding(loff.lnum, &loff.lnum, NULL);
+#endif
+
+ /* Always scroll at least one line. Avoid getting stuck on
+ * very long lines. */
+ if (loff.lnum >= curwin->w_topline
+#ifdef FEAT_DIFF
+ && (loff.lnum > curwin->w_topline
+ || loff.fill >= curwin->w_topfill)
+#endif
+ )
+ {
+#ifdef FEAT_DIFF
+ /* First try using the maximum number of filler lines. If
+ * that's not enough, backup one line. */
+ loff.fill = curwin->w_topfill;
+ if (curwin->w_topfill < diff_check_fill(curwin,
+ curwin->w_topline))
+ max_topfill();
+ if (curwin->w_topfill == loff.fill)
+#endif
+ {
+ --curwin->w_topline;
+#ifdef FEAT_DIFF
+ curwin->w_topfill = 0;
+#endif
+ }
+ comp_botline(curwin);
+ curwin->w_cursor.lnum = curwin->w_botline - 1;
+ curwin->w_valid &= ~(VALID_WCOL|VALID_CHEIGHT|
+ VALID_WROW|VALID_CROW);
+ }
+ else
+ {
+ curwin->w_topline = loff.lnum;
+#ifdef FEAT_DIFF
+ curwin->w_topfill = loff.fill;
+ check_topfill(curwin, FALSE);
+#endif
+ curwin->w_valid &= ~(VALID_WROW|VALID_CROW|VALID_BOTLINE);
+ }
+ }
+ }
+ }
+#ifdef FEAT_FOLDING
+ foldAdjustCursor();
+#endif
+ cursor_correct();
+ if (retval == OK)
+ beginline(BL_SOL | BL_FIX);
+ curwin->w_valid &= ~(VALID_WCOL|VALID_WROW|VALID_VIRTCOL);
+
+ /*
+ * Avoid the screen jumping up and down when 'scrolloff' is non-zero.
+ * But make sure we scroll at least one line (happens with mix of long
+ * wrapping lines and non-wrapping line).
+ */
+ if (retval == OK && dir == FORWARD && check_top_offset())
+ {
+ scroll_cursor_top(1, FALSE);
+ if (curwin->w_topline <= old_topline
+ && old_topline < curbuf->b_ml.ml_line_count)
+ {
+ curwin->w_topline = old_topline + 1;
+#ifdef FEAT_FOLDING
+ (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
+#endif
+ }
+ }
+
+ redraw_later(VALID);
+ return retval;
+}
+
+/*
+ * Decide how much overlap to use for page-up or page-down scrolling.
+ * This is symmetric, so that doing both keeps the same lines displayed.
+ * Three lines are examined:
+ *
+ * before CTRL-F after CTRL-F / before CTRL-B
+ * etc. l1
+ * l1 last but one line ------------
+ * l2 last text line l2 top text line
+ * ------------- l3 second text line
+ * l3 etc.
+ */
+ static void
+get_scroll_overlap(lp, dir)
+ lineoff_T *lp;
+ int dir;
+{
+ int h1, h2, h3, h4;
+ int min_height = curwin->w_height - 2;
+ lineoff_T loff0, loff1, loff2;
+
+#ifdef FEAT_DIFF
+ if (lp->fill > 0)
+ lp->height = 1;
+ else
+ lp->height = plines_nofill(lp->lnum);
+#else
+ lp->height = plines(lp->lnum);
+#endif
+ h1 = lp->height;
+ if (h1 > min_height)
+ return; /* no overlap */
+
+ loff0 = *lp;
+ if (dir > 0)
+ botline_forw(lp);
+ else
+ topline_back(lp);
+ h2 = lp->height;
+ if (h2 + h1 > min_height)
+ {
+ *lp = loff0; /* no overlap */
+ return;
+ }
+
+ loff1 = *lp;
+ if (dir > 0)
+ botline_forw(lp);
+ else
+ topline_back(lp);
+ h3 = lp->height;
+ if (h3 + h2 > min_height)
+ {
+ *lp = loff0; /* no overlap */
+ return;
+ }
+
+ loff2 = *lp;
+ if (dir > 0)
+ botline_forw(lp);
+ else
+ topline_back(lp);
+ h4 = lp->height;
+ if (h4 + h3 + h2 > min_height || h3 + h2 + h1 > min_height)
+ *lp = loff1; /* 1 line overlap */
+ else
+ *lp = loff2; /* 2 lines overlap */
+ return;
+}
+
+/* #define KEEP_SCREEN_LINE */
+/*
+ * Scroll 'scroll' lines up or down.
+ */
+ void
+halfpage(flag, Prenum)
+ int flag;
+ linenr_T Prenum;
+{
+ long scrolled = 0;
+ int i;
+ int n;
+ int room;
+
+ if (Prenum)
+ curwin->w_p_scr = (Prenum > curwin->w_height) ?
+ curwin->w_height : Prenum;
+ n = (curwin->w_p_scr <= curwin->w_height) ?
+ curwin->w_p_scr : curwin->w_height;
+
+ validate_botline();
+ room = curwin->w_empty_rows;
+#ifdef FEAT_DIFF
+ room += curwin->w_filler_rows;
+#endif
+ if (flag)
+ {
+ /*
+ * scroll the text up
+ */
+ while (n > 0 && curwin->w_botline <= curbuf->b_ml.ml_line_count)
+ {
+#ifdef FEAT_DIFF
+ if (curwin->w_topfill > 0)
+ {
+ i = 1;
+ if (--n < 0 && scrolled > 0)
+ break;
+ --curwin->w_topfill;
+ }
+ else
+#endif
+ {
+#ifdef FEAT_DIFF
+ i = plines_nofill(curwin->w_topline);
+#else
+ i = plines(curwin->w_topline);
+#endif
+ n -= i;
+ if (n < 0 && scrolled > 0)
+ break;
+#ifdef FEAT_FOLDING
+ (void)hasFolding(curwin->w_topline, NULL, &curwin->w_topline);
+#endif
+ ++curwin->w_topline;
+#ifdef FEAT_DIFF
+ curwin->w_topfill = diff_check_fill(curwin, curwin->w_topline);
+#endif
+
+#ifndef KEEP_SCREEN_LINE
+ if (curwin->w_cursor.lnum < curbuf->b_ml.ml_line_count)
+ {
+ ++curwin->w_cursor.lnum;
+ curwin->w_valid &=
+ ~(VALID_VIRTCOL|VALID_CHEIGHT|VALID_WCOL);
+ }
+#endif
+ }
+ curwin->w_valid &= ~(VALID_CROW|VALID_WROW);
+ scrolled += i;
+
+ /*
+ * Correct w_botline for changed w_topline.
+ * Won't work when there are filler lines.
+ */
+#ifdef FEAT_DIFF
+ if (curwin->w_p_diff)
+ curwin->w_valid &= ~(VALID_BOTLINE|VALID_BOTLINE_AP);
+ else
+#endif
+ {
+ room += i;
+ do
+ {
+ i = plines(curwin->w_botline);
+ if (i > room)
+ break;
+#ifdef FEAT_FOLDING
+ (void)hasFolding(curwin->w_botline, NULL,
+ &curwin->w_botline);
+#endif
+ ++curwin->w_botline;
+ room -= i;
+ } while (curwin->w_botline <= curbuf->b_ml.ml_line_count);
+ }
+ }
+
+#ifndef KEEP_SCREEN_LINE
+ /*
+ * When hit bottom of the file: move cursor down.
+ */
+ if (n > 0)
+ {
+# ifdef FEAT_FOLDING
+ if (hasAnyFolding(curwin))
+ {
+ while (--n >= 0
+ && curwin->w_cursor.lnum < curbuf->b_ml.ml_line_count)
+ {
+ (void)hasFolding(curwin->w_cursor.lnum, NULL,
+ &curwin->w_cursor.lnum);
+ ++curwin->w_cursor.lnum;
+ }
+ }
+ else
+# endif
+ curwin->w_cursor.lnum += n;
+ check_cursor_lnum();
+ }
+#else
+ /* try to put the cursor in the same screen line */
+ while ((curwin->w_cursor.lnum < curwin->w_topline || scrolled > 0)
+ && curwin->w_cursor.lnum < curwin->w_botline - 1)
+ {
+ scrolled -= plines(curwin->w_cursor.lnum);
+ if (scrolled < 0 && curwin->w_cursor.lnum >= curwin->w_topline)
+ break;
+# ifdef FEAT_FOLDING
+ (void)hasFolding(curwin->w_cursor.lnum, NULL,
+ &curwin->w_cursor.lnum);
+# endif
+ ++curwin->w_cursor.lnum;
+ }
+#endif
+ }
+ else
+ {
+ /*
+ * scroll the text down
+ */
+ while (n > 0 && curwin->w_topline > 1)
+ {
+#ifdef FEAT_DIFF
+ if (curwin->w_topfill < diff_check_fill(curwin, curwin->w_topline))
+ {
+ i = 1;
+ if (--n < 0 && scrolled > 0)
+ break;
+ ++curwin->w_topfill;
+ }
+ else
+#endif
+ {
+#ifdef FEAT_DIFF
+ i = plines_nofill(curwin->w_topline - 1);
+#else
+ i = plines(curwin->w_topline - 1);
+#endif
+ n -= i;
+ if (n < 0 && scrolled > 0)
+ break;
+ --curwin->w_topline;
+#ifdef FEAT_FOLDING
+ (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
+#endif
+#ifdef FEAT_DIFF
+ curwin->w_topfill = 0;
+#endif
+ }
+ curwin->w_valid &= ~(VALID_CROW|VALID_WROW|
+ VALID_BOTLINE|VALID_BOTLINE_AP);
+ scrolled += i;
+#ifndef KEEP_SCREEN_LINE
+ if (curwin->w_cursor.lnum > 1)
+ {
+ --curwin->w_cursor.lnum;
+ curwin->w_valid &= ~(VALID_VIRTCOL|VALID_CHEIGHT|VALID_WCOL);
+ }
+#endif
+ }
+#ifndef KEEP_SCREEN_LINE
+ /*
+ * When hit top of the file: move cursor up.
+ */
+ if (n > 0)
+ {
+ if (curwin->w_cursor.lnum <= (linenr_T)n)
+ curwin->w_cursor.lnum = 1;
+ else
+# ifdef FEAT_FOLDING
+ if (hasAnyFolding(curwin))
+ {
+ while (--n >= 0 && curwin->w_cursor.lnum > 1)
+ {
+ --curwin->w_cursor.lnum;
+ (void)hasFolding(curwin->w_cursor.lnum,
+ &curwin->w_cursor.lnum, NULL);
+ }
+ }
+ else
+# endif
+ curwin->w_cursor.lnum -= n;
+ }
+#else
+ /* try to put the cursor in the same screen line */
+ scrolled += n; /* move cursor when topline is 1 */
+ while (curwin->w_cursor.lnum > curwin->w_topline
+ && (scrolled > 0 || curwin->w_cursor.lnum >= curwin->w_botline))
+ {
+ scrolled -= plines(curwin->w_cursor.lnum - 1);
+ if (scrolled < 0 && curwin->w_cursor.lnum < curwin->w_botline)
+ break;
+ --curwin->w_cursor.lnum;
+# ifdef FEAT_FOLDING
+ foldAdjustCursor();
+# endif
+ }
+#endif
+ }
+# ifdef FEAT_FOLDING
+ /* Move cursor to first line of closed fold. */
+ foldAdjustCursor();
+# endif
+#ifdef FEAT_DIFF
+ check_topfill(curwin, !flag);
+#endif
+ cursor_correct();
+ beginline(BL_SOL | BL_FIX);
+ redraw_later(VALID);
+}
+
+#if defined(FEAT_CURSORBIND) || defined(PROTO)
+ void
+do_check_cursorbind()
+{
+ linenr_T line = curwin->w_cursor.lnum;
+ colnr_T col = curwin->w_cursor.col;
+ win_T *old_curwin = curwin;
+ buf_T *old_curbuf = curbuf;
+ int restart_edit_save;
+# ifdef FEAT_VISUAL
+ int old_VIsual_select = VIsual_select;
+ int old_VIsual_active = VIsual_active;
+# endif
+
+ /*
+ * loop through the cursorbound windows
+ */
+# ifdef FEAT_VISUAL
+ VIsual_select = VIsual_active = 0;
+# endif
+ for (curwin = firstwin; curwin; curwin = curwin->w_next)
+ {
+ curbuf = curwin->w_buffer;
+ /* skip original window and windows with 'noscrollbind' */
+ if (curwin != old_curwin && curwin->w_p_crb)
+ {
+# ifdef FEAT_DIFF
+ if (curwin->w_p_diff)
+ curwin->w_cursor.lnum
+ = diff_get_corresponding_line(old_curbuf,
+ line,
+ curbuf,
+ curwin->w_cursor.lnum);
+ else
+# endif
+ curwin->w_cursor.lnum = line;
+ curwin->w_cursor.col = col;
+
+ /* Make sure the cursor is in a valid position. Temporarily set
+ * "restart_edit" to allow the cursor to be beyond the EOL. */
+ restart_edit_save = restart_edit;
+ restart_edit = TRUE;
+ check_cursor();
+ restart_edit = restart_edit_save;
+# ifdef FEAT_MBYTE
+ /* Correct cursor for multi-byte character. */
+ if (has_mbyte)
+ mb_adjust_cursor();
+# endif
+ redraw_later(VALID);
+
+ /* Only scroll when 'scrollbind' hasn't done this. */
+ if (!curwin->w_p_scb)
+ update_topline();
+# ifdef FEAT_WINDOWS
+ curwin->w_redr_status = TRUE;
+# endif
+ }
+ }
+
+ /*
+ * reset current-window
+ */
+# ifdef FEAT_VISUAL
+ VIsual_select = old_VIsual_select;
+ VIsual_active = old_VIsual_active;
+# endif
+ curwin = old_curwin;
+ curbuf = old_curbuf;
+}
+#endif /* FEAT_CURSORBIND */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-28 20:21:51 +0000