Introduce nvim namespace: Move files.

Move files from src/ to src/nvim/.
- src/nvim/ becomes the new root dir for nvim executable sources.
- src/libnvim/ is planned to become root dir of the neovim library.

1 files changed, 2242 insertions, 0 deletions

diff --git a/src/nvim/move.c b/src/nvim/move.c
new file mode 100644
index 0000000000..f234d968a6
--- /dev/null
+++ b/src/nvim/move.c
@@ -0,0 +1,2242 @@
+/*
+ * 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"
+#include "move.h"
+#include "charset.h"
+#include "diff.h"
+#include "edit.h"
+#include "fold.h"
+#include "mbyte.h"
+#include "memline.h"
+#include "misc1.h"
+#include "misc2.h"
+#include "popupmnu.h"
+#include "screen.h"
+
+static void comp_botline(win_T *wp);
+static void redraw_for_cursorline(win_T *wp);
+static int scrolljump_value(void);
+static int check_top_offset(void);
+static void curs_rows(win_T *wp, int do_botline);
+static void validate_botline_win(win_T *wp);
+static void validate_cheight(void);
+
+typedef struct {
+  linenr_T lnum;                /* line number */
+  int fill;                     /* filler lines */
+  int height;                   /* height of added line */
+} lineoff_T;
+
+static void topline_back(lineoff_T *lp);
+static void botline_forw(lineoff_T *lp);
+static void botline_topline(lineoff_T *lp);
+static void topline_botline(lineoff_T *lp);
+static void max_topfill(void);
+
+/*
+ * Compute wp->w_botline for the current wp->w_topline.  Can be called after
+ * wp->w_topline changed.
+ */
+static void comp_botline(win_T *wp)
+{
+  int n;
+  linenr_T lnum;
+  int done;
+  linenr_T last;
+  int folded;
+
+  /*
+   * 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) {
+    last = lnum;
+    folded = FALSE;
+    if (hasFoldingWin(wp, lnum, NULL, &last, TRUE, NULL)) {
+      n = 1;
+      folded = TRUE;
+    } else if (lnum == wp->w_topline)
+      n = plines_win_nofill(wp, lnum, TRUE) + wp->w_topfill;
+    else
+      n = plines_win(wp, lnum, TRUE);
+    if (
+      lnum <= wp->w_cursor.lnum && last >= wp->w_cursor.lnum
+      ) {
+      wp->w_cline_row = done;
+      wp->w_cline_height = n;
+      wp->w_cline_folded = folded;
+      redraw_for_cursorline(wp);
+      wp->w_valid |= (VALID_CROW|VALID_CHEIGHT);
+    }
+    if (done + n > wp->w_height)
+      break;
+    done += n;
+    lnum = last;
+  }
+
+  /* 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);
+}
+
+/*
+* Redraw when w_cline_row changes and 'relativenumber' or 'cursorline' is
+* set.
+*/
+static void redraw_for_cursorline(win_T *wp)
+{
+  if ((wp->w_p_rnu || wp->w_p_cul)
+      && (wp->w_valid & VALID_CROW) == 0
+      && !pum_visible()) {
+    redraw_win_later(wp, SOME_VALID);
+  }
+}
+
+/*
+ * Update curwin->w_topline and redraw if necessary.
+ * Used to update the screen before printing a message.
+ */
+void update_topline_redraw(void)
+{
+  update_topline();
+  if (must_redraw)
+    update_screen(0);
+}
+
+/*
+ * Update curwin->w_topline to move the cursor onto the screen.
+ */
+void update_topline(void)
+{
+  long line_count;
+  int halfheight;
+  int n;
+  linenr_T old_topline;
+  int old_topfill;
+  linenr_T lnum;
+  int check_topline = FALSE;
+  int check_botline = FALSE;
+  int save_so = p_so;
+
+  if (!screen_valid(TRUE))
+    return;
+
+  check_cursor_moved(curwin);
+  if (curwin->w_valid & VALID_TOPLINE)
+    return;
+
+  /* When dragging with the mouse, don't scroll that quickly */
+  if (mouse_dragging > 0)
+    p_so = mouse_dragging - 1;
+
+  old_topline = curwin->w_topline;
+  old_topfill = curwin->w_topfill;
+
+  /*
+   * 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;
+    curwin->w_scbind_pos = 1;
+  }
+  /*
+   * 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;
+    }
+    /* 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;
+
+    if (check_topline) {
+      halfheight = curwin->w_height / 2 - 1;
+      if (halfheight < 2)
+        halfheight = 2;
+
+      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
+        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 {
+      /* Make sure topline is the first line of a fold. */
+      (void)hasFolding(curwin->w_topline, &curwin->w_topline, NULL);
+      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
+             || hasAnyFolding(curwin)
+             )) {
+          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;
+          /* In a fold go to its last line. */
+          (void)hasFolding(loff.lnum, NULL, &loff.lnum);
+          loff.fill = 0;
+          n += curwin->w_filler_rows;
+          loff.height = 0;
+          while (loff.lnum < curwin->w_botline
+                 && (loff.lnum + 1 < curwin->w_botline || loff.fill == 0)
+                 ) {
+            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) {
+        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
+          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
+      || curwin->w_topfill != old_topfill
+      ) {
+    dollar_vcol = -1;
+    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();
+  }
+
+  p_so = save_so;
+}
+
+/*
+ * 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(void)
+{
+  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(void)
+{
+  lineoff_T loff;
+  int n;
+
+  if (curwin->w_cursor.lnum < curwin->w_topline + p_so
+      || hasAnyFolding(curwin)
+      ) {
+    loff.lnum = curwin->w_cursor.lnum;
+    loff.fill = 0;
+    n = curwin->w_topfill;          /* always have this context */
+    /* 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
+          || (loff.lnum == curwin->w_topline && loff.fill > 0)
+          )
+        break;
+      n += loff.height;
+    }
+    if (n < p_so)
+      return TRUE;
+  }
+  return FALSE;
+}
+
+void update_curswant(void)
+{
+  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(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
+             || wp->w_cursor.coladd != wp->w_valid_cursor.coladd
+             ) {
+    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;
+    wp->w_valid_cursor.coladd = wp->w_cursor.coladd;
+  }
+}
+
+/*
+ * 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(void)
+{
+  changed_window_setting_win(curwin);
+}
+
+void changed_window_setting_win(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(win_T *wp, linenr_T lnum)
+{
+  /* go to first of folded lines */
+  (void)hasFoldingWin(wp, lnum, &lnum, NULL, TRUE, NULL);
+  /* Approximate the value of w_botline */
+  wp->w_botline += lnum - wp->w_topline;
+  wp->w_topline = lnum;
+  wp->w_topline_was_set = TRUE;
+  wp->w_topfill = 0;
+  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(void)
+{
+  curwin->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL
+                       |VALID_CHEIGHT|VALID_TOPLINE);
+}
+
+void changed_cline_bef_curs_win(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(void)
+{
+  curwin->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL|VALID_CROW
+                       |VALID_CHEIGHT|VALID_TOPLINE);
+}
+
+void changed_line_abv_curs_win(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(void)
+{
+  if (!(curwin->w_valid & VALID_BOTLINE))
+    comp_botline(curwin);
+}
+
+/*
+ * Make sure the value of wp->w_botline is valid.
+ */
+static void validate_botline_win(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(void)
+{
+  curwin->w_valid &= ~(VALID_BOTLINE|VALID_BOTLINE_AP);
+}
+
+void invalidate_botline_win(win_T *wp)
+{
+  wp->w_valid &= ~(VALID_BOTLINE|VALID_BOTLINE_AP);
+}
+
+void approximate_botline_win(win_T *wp)
+{
+  wp->w_valid &= ~VALID_BOTLINE;
+}
+
+/*
+ * Return TRUE if curwin->w_wrow and curwin->w_wcol are valid.
+ */
+int cursor_valid(void)
+{
+  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(void)
+{
+  check_cursor_moved(curwin);
+  if ((curwin->w_valid & (VALID_WCOL|VALID_WROW)) != (VALID_WCOL|VALID_WROW))
+    curs_columns(TRUE);
+}
+
+/*
+ * 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 (
+    win_T *wp,
+    int do_botline                         /* also compute w_botline */
+)
+{
+  linenr_T lnum;
+  int i;
+  int all_invalid;
+  int valid;
+  long fold_count;
+
+  /* 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) {
+        /* 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)
+          valid = TRUE;
+      } else if (wp->w_lines[i].wl_lnum > lnum)
+        --i;                            /* hold at inserted lines */
+    }
+    if (valid
+        && (lnum != wp->w_topline || !wp->w_p_diff)
+        ) {
+      lnum = wp->w_lines[i].wl_lastlnum + 1;
+      /* Cursor inside folded lines, don't count this row */
+      if (lnum > wp->w_cursor.lnum)
+        break;
+      wp->w_cline_row += wp->w_lines[i].wl_size;
+    } else {
+      fold_count = foldedCount(wp, lnum, NULL);
+      if (fold_count) {
+        lnum += fold_count;
+        if (lnum > wp->w_cursor.lnum)
+          break;
+        ++wp->w_cline_row;
+      } else if (lnum == wp->w_topline)
+        wp->w_cline_row += plines_win_nofill(wp, lnum++, TRUE)
+                           + wp->w_topfill;
+      else
+        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))) {
+      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
+        wp->w_cline_height = plines_win(wp, wp->w_cursor.lnum, TRUE);
+      wp->w_cline_folded = hasFoldingWin(wp, wp->w_cursor.lnum,
+          NULL, NULL, TRUE, NULL);
+    } 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;
+      wp->w_cline_folded = hasFoldingWin(wp, wp->w_cursor.lnum,
+          NULL, NULL, TRUE, NULL);
+    } else {
+      wp->w_cline_height = wp->w_lines[i].wl_size;
+      wp->w_cline_folded = wp->w_lines[i].wl_folded;
+    }
+  }
+
+  redraw_for_cursorline(curwin);
+  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(void)
+{
+  validate_virtcol_win(curwin);
+}
+
+/*
+ * Validate wp->w_virtcol only.
+ */
+void validate_virtcol_win(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;
+    if (wp->w_p_cuc
+        && !pum_visible()
+        )
+      redraw_win_later(wp, SOME_VALID);
+  }
+}
+
+/*
+ * Validate curwin->w_cline_height only.
+ */
+static void validate_cheight(void)
+{
+  check_cursor_moved(curwin);
+  if (!(curwin->w_valid & VALID_CHEIGHT)) {
+    if (curwin->w_cursor.lnum == curwin->w_topline)
+      curwin->w_cline_height = plines_nofill(curwin->w_cursor.lnum)
+                               + curwin->w_topfill;
+    else
+      curwin->w_cline_height = plines(curwin->w_cursor.lnum);
+    curwin->w_cline_folded = hasFolding(curwin->w_cursor.lnum, NULL, NULL);
+    curwin->w_valid |= VALID_CHEIGHT;
+  }
+}
+
+/*
+ * Validate w_wcol and w_virtcol only.
+ */
+void validate_cursor_col(void)
+{
+  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(win_T *wp)
+{
+  return ((wp->w_p_nu || wp->w_p_rnu) ? number_width(wp) + 1 : 0)
+         + (cmdwin_type == 0 || wp != curwin ? 0 : 1)
+         + wp->w_p_fdc
+         + (wp->w_buffer->b_signlist != NULL ? 2 : 0)
+  ;
+}
+
+int curwin_col_off(void)
+{
+  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(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(void)
+{
+  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 (
+    int may_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.
+   */
+  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
+    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 = -1;
+
+  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
+             && curwin->w_width != 0
+             ) {
+    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;
+
+      /* 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;
+    }
+  }
+  /* 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 (may_scroll
+           && !curwin->w_cline_folded
+           ) {
+    /*
+     * 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;
+
+  /* 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);
+
+  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 =
+                 plines_win_nofill
+                   (curwin, curwin->w_cursor.lnum, FALSE))
+           - 1 >= curwin->w_height))
+      && curwin->w_height != 0
+      && curwin->w_cursor.lnum == curwin->w_topline
+      && width > 0
+      && curwin->w_width != 0
+      ) {
+    /* 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_virtcol changes and 'cursorcolumn' is set */
+  if (curwin->w_p_cuc && (curwin->w_valid & VALID_VIRTCOL) == 0
+      && !pum_visible()) {
+    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 (
+    long line_count,
+    int byfold              /* TRUE: count a closed fold as one line */
+)
+{
+  long done = 0;                /* total # of physical lines done */
+  int wrow;
+  int moved = FALSE;
+
+  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);
+  validate_cursor();            /* w_wrow needs to be valid */
+  while (line_count-- > 0) {
+    if (curwin->w_topfill < diff_check(curwin, curwin->w_topline)
+        && curwin->w_topfill < curwin->w_height - 1) {
+      ++curwin->w_topfill;
+      ++done;
+    } else {
+      if (curwin->w_topline == 1)
+        break;
+      --curwin->w_topline;
+      curwin->w_topfill = 0;
+      /* 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
+        done += plines_nofill(curwin->w_topline);
+    }
+    --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 */
+
+  if (curwin->w_cursor.lnum == curwin->w_topline)
+    curwin->w_cline_row = 0;
+  check_topfill(curwin, TRUE);
+
+  /*
+   * 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
+      && curwin->w_width != 0
+      ) {
+    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) {
+    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
+      wrow -= plines(curwin->w_cursor.lnum--);
+    curwin->w_valid &=
+      ~(VALID_WROW|VALID_WCOL|VALID_CHEIGHT|VALID_CROW|VALID_VIRTCOL);
+    moved = TRUE;
+  }
+  if (moved) {
+    /* Move cursor to first line of closed fold. */
+    foldAdjustCursor();
+    coladvance(curwin->w_curswant);
+  }
+}
+
+/*
+ * Scroll the current window up by "line_count" logical lines.  "CTRL-E"
+ */
+void 
+scrollup (
+    long line_count,
+    int byfold              /* TRUE: count a closed fold as one line */
+)
+{
+  linenr_T lnum;
+
+  if (
+    (byfold && hasAnyFolding(curwin))
+    ||
+    curwin->w_p_diff
+    ) {
+    /* count each sequence of folded lines as one logical line */
+    lnum = curwin->w_topline;
+    while (line_count--) {
+      if (curwin->w_topfill > 0)
+        --curwin->w_topfill;
+      else {
+        if (byfold)
+          (void)hasFolding(lnum, NULL, &lnum);
+        if (lnum >= curbuf->b_ml.ml_line_count)
+          break;
+        ++lnum;
+        curwin->w_topfill = diff_check_fill(curwin, lnum);
+      }
+    }
+    /* approximate w_botline */
+