text: // This is an open source non-commercial project. Dear PVS-Studio, please check
  // it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
  
  /*
   * buffer.c: functions for dealing with the buffer structure
   */
  
  /*
   * The buffer list is a double linked list of all buffers.
   * Each buffer can be in one of these states:
   * never loaded: BF_NEVERLOADED is set, only the file name is valid
   *   not loaded: b_ml.ml_mfp == NULL, no memfile allocated
   *	 hidden: b_nwindows == 0, loaded but not displayed in a window
   *	 normal: loaded and displayed in a window
   *
   * Instead of storing file names all over the place, each file name is
   * stored in the buffer list. It can be referenced by a number.
   *
   * The current implementation remembers all file names ever used.
   */
  
  #include <stdbool.h>
  #include <string.h>
  #include <inttypes.h>
  #include <assert.h>
  
  #include "nvim/api/private/handle.h"
  #include "nvim/api/private/helpers.h"
  #include "nvim/ascii.h"
  #include "nvim/assert.h"
  #include "nvim/vim.h"
  #include "nvim/buffer.h"
  #include "nvim/charset.h"
  #include "nvim/cursor.h"
  #include "nvim/diff.h"
  #include "nvim/digraph.h"
  #include "nvim/eval.h"
  #include "nvim/ex_cmds2.h"
  #include "nvim/ex_cmds.h"
  #include "nvim/ex_docmd.h"
  #include "nvim/ex_eval.h"
  #include "nvim/ex_getln.h"
  #include "nvim/fileio.h"
  #include "nvim/file_search.h"
  #include "nvim/fold.h"
  #include "nvim/getchar.h"
  #include "nvim/hashtab.h"
  #include "nvim/highlight.h"
  #include "nvim/indent.h"
  #include "nvim/indent_c.h"
  #include "nvim/main.h"
  #include "nvim/mark.h"
  #include "nvim/mbyte.h"
  #include "nvim/memline.h"
  #include "nvim/memory.h"
  #include "nvim/message.h"
  #include "nvim/misc1.h"
  #include "nvim/garray.h"
  #include "nvim/move.h"
  #include "nvim/option.h"
  #include "nvim/os_unix.h"
  #include "nvim/path.h"
  #include "nvim/quickfix.h"
  #include "nvim/regexp.h"
  #include "nvim/screen.h"
  #include "nvim/spell.h"
  #include "nvim/strings.h"
  #include "nvim/syntax.h"
  #include "nvim/ui.h"
  #include "nvim/undo.h"
  #include "nvim/version.h"
  #include "nvim/window.h"
  #include "nvim/shada.h"
  #include "nvim/os/os.h"
  #include "nvim/os/time.h"
  #include "nvim/os/input.h"
  #include "nvim/buffer_updates.h"
  
  typedef enum {
    kBLSUnchanged = 0,
    kBLSChanged = 1,
    kBLSDeleted = 2,
  } BufhlLineStatus;
  
  #ifdef INCLUDE_GENERATED_DECLARATIONS
  # include "buffer.c.generated.h"
  #endif
  
  static char *msg_loclist = N_("[Location List]");
  static char *msg_qflist = N_("[Quickfix List]");
  static char *e_auabort = N_("E855: Autocommands caused command to abort");
  
  // Number of times free_buffer() was called.
  static int buf_free_count = 0;
  
  // Read data from buffer for retrying.
  static int
  read_buffer(
      int     read_stdin,     // read file from stdin, otherwise fifo
      exarg_T *eap,           // for forced 'ff' and 'fenc' or NULL
      int     flags)          // extra flags for readfile()
  {
    int       retval = OK;
    linenr_T  line_count;
  
    //
    // Read from the buffer which the text is already filled in and append at
    // the end.  This makes it possible to retry when 'fileformat' or
    // 'fileencoding' was guessed wrong.
    //
    line_count = curbuf->b_ml.ml_line_count;
    retval = readfile(
        read_stdin ? NULL : curbuf->b_ffname,
        read_stdin ? NULL : curbuf->b_fname,
        (linenr_T)line_count, (linenr_T)0, (linenr_T)MAXLNUM, eap,
        flags | READ_BUFFER);
    if (retval == OK) {
      // Delete the binary lines.
      while (--line_count >= 0) {
        ml_delete((linenr_T)1, false);
      }
    } else {
      // Delete the converted lines.
      while (curbuf->b_ml.ml_line_count > line_count) {
        ml_delete(line_count, false);
      }
    }
    // Put the cursor on the first line.
    curwin->w_cursor.lnum = 1;
    curwin->w_cursor.col = 0;
  
    if (read_stdin) {
      // Set or reset 'modified' before executing autocommands, so that
      // it can be changed there.
      if (!readonlymode && !BUFEMPTY()) {
        changed();
      } else if (retval != FAIL) {
        unchanged(curbuf, false);
      }
  
      apply_autocmds_retval(EVENT_STDINREADPOST, NULL, NULL, false,
                            curbuf, &retval);
    }
    return retval;
  }
  
  /*
   * Open current buffer, that is: open the memfile and read the file into
   * memory.
   * Return FAIL for failure, OK otherwise.
   */
  int 
  open_buffer (
      int read_stdin,                     /* read file from stdin */
      exarg_T *eap,                   /* for forced 'ff' and 'fenc' or NULL */
      int flags                          /* extra flags for readfile() */
  )
  {
    int retval = OK;
    bufref_T       old_curbuf;
    long old_tw = curbuf->b_p_tw;
    int read_fifo = false;
  
    /*
     * The 'readonly' flag is only set when BF_NEVERLOADED is being reset.
     * When re-entering the same buffer, it should not change, because the
     * user may have reset the flag by hand.
     */
    if (readonlymode && curbuf->b_ffname != NULL
        && (curbuf->b_flags & BF_NEVERLOADED))
      curbuf->b_p_ro = TRUE;
  
    if (ml_open(curbuf) == FAIL) {
      /*
       * There MUST be a memfile, otherwise we can't do anything
       * If we can't create one for the current buffer, take another buffer
       */
      close_buffer(NULL, curbuf, 0, FALSE);
  
      curbuf = NULL;
      FOR_ALL_BUFFERS(buf) {
        if (buf->b_ml.ml_mfp != NULL) {
          curbuf = buf;
          break;
        }
      }
  
      /*
       * if there is no memfile at all, exit
       * This is OK, since there are no changes to lose.
       */
      if (curbuf == NULL) {
        EMSG(_("E82: Cannot allocate any buffer, exiting..."));
        getout(2);
      }
      EMSG(_("E83: Cannot allocate buffer, using other one..."));
      enter_buffer(curbuf);
      if (old_tw != curbuf->b_p_tw)
        check_colorcolumn(curwin);
      return FAIL;
    }
  
    // The autocommands in readfile() may change the buffer, but only AFTER
    // reading the file.
    set_bufref(&old_curbuf, curbuf);
    modified_was_set = false;
  
    /* mark cursor position as being invalid */
    curwin->w_valid = 0;
  
    if (curbuf->b_ffname != NULL) {
      int old_msg_silent = msg_silent;
  #ifdef UNIX
      int save_bin = curbuf->b_p_bin;
      int perm;
  
      perm = os_getperm((const char *)curbuf->b_ffname);
      if (perm >= 0 && (0
  # ifdef S_ISFIFO
                        || S_ISFIFO(perm)
  # endif
  # ifdef S_ISSOCK
                        || S_ISSOCK(perm)
  # endif
  # ifdef OPEN_CHR_FILES
                        || (S_ISCHR(perm)
                            && is_dev_fd_file(curbuf->b_ffname))
  # endif
                        )
          ) {
        read_fifo = true;
      }
      if (read_fifo) {
        curbuf->b_p_bin = true;
      }
  #endif
      if (shortmess(SHM_FILEINFO)) {
        msg_silent = 1;
      }
  
      retval = readfile(curbuf->b_ffname, curbuf->b_fname,
                        (linenr_T)0, (linenr_T)0, (linenr_T)MAXLNUM, eap,
                        flags | READ_NEW | (read_fifo ? READ_FIFO : 0));
  #ifdef UNIX
      if (read_fifo) {
        curbuf->b_p_bin = save_bin;
        if (retval == OK) {
          retval = read_buffer(false, eap, flags);
        }
      }
  #endif
      msg_silent = old_msg_silent;
  
      // Help buffer is filtered.
      if (bt_help(curbuf)) {
        fix_help_buffer();
      }
    } else if (read_stdin) {
      int save_bin = curbuf->b_p_bin;
  
      /*
       * First read the text in binary mode into the buffer.
       * Then read from that same buffer and append at the end.  This makes
       * it possible to retry when 'fileformat' or 'fileencoding' was
       * guessed wrong.
       */
      curbuf->b_p_bin = TRUE;
      retval = readfile(NULL, NULL, (linenr_T)0,
          (linenr_T)0, (linenr_T)MAXLNUM, NULL,
          flags | (READ_NEW + READ_STDIN));
      curbuf->b_p_bin = save_bin;
      if (retval == OK) {
        retval = read_buffer(true, eap, flags);
      }
    }
  
    /* if first time loading this buffer, init b_chartab[] */
    if (curbuf->b_flags & BF_NEVERLOADED) {
      (void)buf_init_chartab(curbuf, false);
      parse_cino(curbuf);
    }
  
    // Set/reset the Changed flag first, autocmds may change the buffer.
    // Apply the automatic commands, before processing the modelines.
    // So the modelines have priority over auto commands.
  
    // When reading stdin, the buffer contents always needs writing, so set
    // the changed flag.  Unless in readonly mode: "ls | nvim -R -".
    // When interrupted and 'cpoptions' contains 'i' set changed flag.
    if ((got_int && vim_strchr(p_cpo, CPO_INTMOD) != NULL)
        || modified_was_set               // ":set modified" used in autocmd
        || (aborting() && vim_strchr(p_cpo, CPO_INTMOD) != NULL)) {
      changed();
    } else if (retval != FAIL && !read_stdin && !read_fifo) {
      unchanged(curbuf, false);
    }
    save_file_ff(curbuf);                 // keep this fileformat
  
    // Set last_changedtick to avoid triggering a TextChanged autocommand right
    // after it was added.
    curbuf->b_last_changedtick = buf_get_changedtick(curbuf);
    curbuf->b_last_changedtick_pum = buf_get_changedtick(curbuf);
  
    /* require "!" to overwrite the file, because it wasn't read completely */
    if (aborting())
      curbuf->b_flags |= BF_READERR;
  
    /* Need to update automatic folding.  Do this before the autocommands,
     * they may use the fold info. */
    foldUpdateAll(curwin);
  
    /* need to set w_topline, unless some autocommand already did that. */
    if (!(curwin->w_valid & VALID_TOPLINE)) {
      curwin->w_topline = 1;
      curwin->w_topfill = 0;
    }
    apply_autocmds_retval(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf, &retval);
  
    if (retval == FAIL) {
      return FAIL;
    }
  
    /*
     * The autocommands may have changed the current buffer.  Apply the
     * modelines to the correct buffer, if it still exists and is loaded.
     */
    if (bufref_valid(&old_curbuf) && old_curbuf.br_buf->b_ml.ml_mfp != NULL) {
      aco_save_T aco;
  
      // Go to the buffer that was opened.
      aucmd_prepbuf(&aco, old_curbuf.br_buf);
      do_modelines(0);
      curbuf->b_flags &= ~(BF_CHECK_RO | BF_NEVERLOADED);
  
      apply_autocmds_retval(EVENT_BUFWINENTER, NULL, NULL, FALSE, curbuf,
          &retval);
  
      /* restore curwin/curbuf and a few other things */
      aucmd_restbuf(&aco);
    }
  
    return retval;
  }
  
  /// Store "buf" in "bufref" and set the free count.
  ///
  /// @param bufref Reference to be used for the buffer.
  /// @param buf    The buffer to reference.
  void set_bufref(bufref_T *bufref, buf_T *buf)
  {
    bufref->br_buf = buf;
    bufref->br_fnum = buf == NULL ? 0 : buf->b_fnum;
    bufref->br_buf_free_count = buf_free_count;
  }
  
  /// Return true if "bufref->br_buf" points to the same buffer as when
  /// set_bufref() was called and it is a valid buffer.
  /// Only goes through the buffer list if buf_free_count changed.
  /// Also checks if b_fnum is still the same, a :bwipe followed by :new might get
  /// the same allocated memory, but it's a different buffer.
  ///
  /// @param bufref Buffer reference to check for.
  bool bufref_valid(bufref_T *bufref)
  {
    return bufref->br_buf_free_count == buf_free_count
      ? true
      : buf_valid(bufref->br_buf) && bufref->br_fnum == bufref->br_buf->b_fnum;
  }
  
  /// Check that "buf" points to a valid buffer in the buffer list.
  ///
  /// Can be slow if there are many buffers, prefer using bufref_valid().
  ///
  /// @param buf The buffer to check for.
  bool buf_valid(buf_T *buf)
    FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
  {
    if (buf == NULL) {
      return false;
    }
    // Assume that we more often have a recent buffer,
    // start with the last one.
    for (buf_T *bp = lastbuf; bp != NULL; bp = bp->b_prev) {
      if (bp == buf) {
        return true;
      }
    }
    return false;
  }
  
  /// Close the link to a buffer.
  ///
  /// @param win    If not NULL, set b_last_cursor.
  /// @param buf
  /// @param action Used when there is no longer a window for the buffer.
  ///               Possible values:
  ///                 0            buffer becomes hidden
  ///                 DOBUF_UNLOAD buffer is unloaded
  ///                 DOBUF_DELETE buffer is unloaded and removed from buffer list
  ///                 DOBUF_WIPE   buffer is unloaded and really deleted
  ///               When doing all but the first one on the current buffer, the
  ///               caller should get a new buffer very soon!
  ///               The 'bufhidden' option can force freeing and deleting.
  /// @param abort_if_last
  ///               If TRUE, do not close the buffer if autocommands cause
  ///               there to be only one window with this buffer. e.g. when
  ///               ":quit" is supposed to close the window but autocommands
  ///               close all other windows.
  void close_buffer(win_T *win, buf_T *buf, int action, int abort_if_last)
  {
    bool unload_buf = (action != 0);
    bool del_buf = (action == DOBUF_DEL || action == DOBUF_WIPE);
    bool wipe_buf = (action == DOBUF_WIPE);
  
    bool is_curwin = (curwin != NULL && curwin->w_buffer == buf);
    win_T *the_curwin = curwin;
    tabpage_T *the_curtab = curtab;
  
    // Force unloading or deleting when 'bufhidden' says so, but not for terminal
    // buffers.
    // The caller must take care of NOT deleting/freeing when 'bufhidden' is
    // "hide" (otherwise we could never free or delete a buffer).
    if (!buf->terminal) {
      if (buf->b_p_bh[0] == 'd') {         // 'bufhidden' == "delete"
        del_buf = true;
        unload_buf = true;
      } else if (buf->b_p_bh[0] == 'w') {  // 'bufhidden' == "wipe"
        del_buf = true;
        unload_buf = true;
        wipe_buf = true;
      } else if (buf->b_p_bh[0] == 'u')    // 'bufhidden' == "unload"
        unload_buf = true;
    }
  
    if (buf->terminal && (unload_buf || del_buf || wipe_buf)) {
      // terminal buffers can only be wiped
      unload_buf = true;
      del_buf = true;
      wipe_buf = true;
    }
  
    // Disallow deleting the buffer when it is locked (already being closed or
    // halfway a command that relies on it). Unloading is allowed.
    if (buf->b_locked > 0 && (del_buf || wipe_buf)) {
      EMSG(_("E937: Attempt to delete a buffer that is in use"));
      return;
    }
  
    if (win_valid_any_tab(win)) {
      // Set b_last_cursor when closing the last window for the buffer.
      // Remember the last cursor position and window options of the buffer.
      // This used to be only for the current window, but then options like
      // 'foldmethod' may be lost with a ":only" command.
      if (buf->b_nwindows == 1) {
        set_last_cursor(win);
      }
      buflist_setfpos(buf, win,
          win->w_cursor.lnum == 1 ? 0 : win->w_cursor.lnum,
          win->w_cursor.col, TRUE);
    }
  
    bufref_T bufref;
    set_bufref(&bufref, buf);
  
    /* When the buffer is no longer in a window, trigger BufWinLeave */
    if (buf->b_nwindows == 1) {
      buf->b_locked++;
      if (apply_autocmds(EVENT_BUFWINLEAVE, buf->b_fname, buf->b_fname, false,
                         buf) && !bufref_valid(&bufref)) {
        // Autocommands deleted the buffer.
        EMSG(_(e_auabort));
        return;
      }
      buf->b_locked--;
      if (abort_if_last && one_window()) {
        /* Autocommands made this the only window. */
        EMSG(_(e_auabort));
        return;
      }
  
      // When the buffer becomes hidden, but is not unloaded, trigger
      // BufHidden
      if (!unload_buf) {
        buf->b_locked++;
        if (apply_autocmds(EVENT_BUFHIDDEN, buf->b_fname, buf->b_fname, false,
                           buf) && !bufref_valid(&bufref)) {
          // Autocommands deleted the buffer.
          EMSG(_(e_auabort));
          return;
        }
        buf->b_locked--;
        if (abort_if_last && one_window()) {
          /* Autocommands made this the only window. */
          EMSG(_(e_auabort));
          return;
        }
      }
      if (aborting())         /* autocmds may abort script processing */
        return;
    }
  
    // If the buffer was in curwin and the window has changed, go back to that
    // window, if it still exists.  This avoids that ":edit x" triggering a
    // "tabnext" BufUnload autocmd leaves a window behind without a buffer.
    if (is_curwin && curwin != the_curwin &&  win_valid_any_tab(the_curwin)) {
      block_autocmds();
      goto_tabpage_win(the_curtab, the_curwin);
      unblock_autocmds();
    }
  
    int nwindows = buf->b_nwindows;
  
    // decrease the link count from windows (unless not in any window)
    if (buf->b_nwindows > 0) {
      buf->b_nwindows--;
    }
  
    if (diffopt_hiddenoff() && !unload_buf && buf->b_nwindows == 0) {
      diff_buf_delete(buf);   // Clear 'diff' for hidden buffer.
    }
  
    /* Return when a window is displaying the buffer or when it's not
     * unloaded. */
    if (buf->b_nwindows > 0 || !unload_buf) {
      return;
    }
  
    if (buf->terminal) {
      terminal_close(buf->terminal, NULL);
    }
  
    /* Always remove the buffer when there is no file name. */
    if (buf->b_ffname == NULL)
      del_buf = TRUE;
  
    /*
     * Free all things allocated for this buffer.
     * Also calls the "BufDelete" autocommands when del_buf is TRUE.
     */
    /* Remember if we are closing the current buffer.  Restore the number of
     * windows, so that autocommands in buf_freeall() don't get confused. */
    bool is_curbuf = (buf == curbuf);
  
    // When closing the current buffer stop Visual mode before freeing
    // anything.
    if (is_curbuf && VIsual_active
  #if defined(EXITFREE)
        && !entered_free_all_mem
  #endif
        ) {
      end_visual_mode();
    }
  
    buf->b_nwindows = nwindows;
  
    buf_freeall(buf, (del_buf ? BFA_DEL : 0) + (wipe_buf ? BFA_WIPE : 0));
  
    if (!bufref_valid(&bufref)) {
      // Autocommands may have deleted the buffer.
      return;
    }
    if (aborting()) {
      // Autocmds may abort script processing.
      return;
    }
  
    /*
     * It's possible that autocommands change curbuf to the one being deleted.
     * This might cause the previous curbuf to be deleted unexpectedly.  But
     * in some cases it's OK to delete the curbuf, because a new one is
     * obtained anyway.  Therefore only return if curbuf changed to the
     * deleted buffer.
     */
    if (buf == curbuf && !is_curbuf)
      return;
  
    if (win_valid_any_tab(win) && win->w_buffer == buf) {
      win->w_buffer = NULL;  // make sure we don't use the buffer now
    }
  
    // Autocommands may have opened or closed windows for this buffer.
    // Decrement the count for the close we do here.
    if (buf->b_nwindows > 0) {
      buf->b_nwindows--;
    }
  
    /* Change directories when the 'acd' option is set. */
    do_autochdir();
  
    // disable buffer updates for the current buffer
    buf_updates_unregister_all(buf);
  
    /*
     * Remove the buffer from the list.
     */
    if (wipe_buf) {
      xfree(buf->b_ffname);
      xfree(buf->b_sfname);
      if (buf->b_prev == NULL)
        firstbuf = buf->b_next;
      else
        buf->b_prev->b_next = buf->b_next;
      if (buf->b_next == NULL)
        lastbuf = buf->b_prev;
      else
        buf->b_next->b_prev = buf->b_prev;
      free_buffer(buf);
    } else {
      if (del_buf) {
        /* Free all internal variables and reset option values, to make
         * ":bdel" compatible with Vim 5.7. */
        free_buffer_stuff(buf, TRUE);
  
        /* Make it look like a new buffer. */
        buf->b_flags = BF_CHECK_RO | BF_NEVERLOADED;
  
        /* Init the options when loaded again. */
        buf->b_p_initialized = false;
      }
      buf_clear_file(buf);
      if (del_buf)
        buf->b_p_bl = FALSE;
    }
  }
  
  /*
   * Make buffer not contain a file.
   */
  void buf_clear_file(buf_T *buf)
  {
    buf->b_ml.ml_line_count = 1;
    unchanged(buf, TRUE);
    buf->b_p_eol = TRUE;
    buf->b_start_eol = TRUE;
    buf->b_p_bomb = FALSE;
    buf->b_start_bomb = FALSE;
    buf->b_ml.ml_mfp = NULL;
    buf->b_ml.ml_flags = ML_EMPTY;                /* empty buffer */
  }
  
  /// Clears the current buffer contents.
  void buf_clear(void)
  {
    linenr_T line_count = curbuf->b_ml.ml_line_count;
    while (!(curbuf->b_ml.ml_flags & ML_EMPTY)) {
      ml_delete((linenr_T)1, false);
    }
    deleted_lines_mark(1, line_count);  // prepare for display
    ml_close(curbuf, true);             // free memline_T
    buf_clear_file(curbuf);
  }
  
  /// buf_freeall() - free all things allocated for a buffer that are related to
  /// the file.  Careful: get here with "curwin" NULL when exiting.
  ///
  /// @param flags BFA_DEL buffer is going to be deleted
  ///              BFA_WIPE buffer is going to be wiped out
  ///              BFA_KEEP_UNDO  do not free undo information
  void buf_freeall(buf_T *buf, int flags)
  {
    bool is_curbuf = (buf == curbuf);
    int is_curwin = (curwin != NULL && curwin->w_buffer == buf);
    win_T *the_curwin = curwin;
    tabpage_T *the_curtab = curtab;
  
    // Make sure the buffer isn't closed by autocommands.
    buf->b_locked++;
  
    bufref_T bufref;
    set_bufref(&bufref, buf);
  
    if ((buf->b_ml.ml_mfp != NULL)
        && apply_autocmds(EVENT_BUFUNLOAD, buf->b_fname, buf->b_fname, false, buf)
        && !bufref_valid(&bufref)) {
      // Autocommands deleted the buffer.
      return;
    }
    if ((flags & BFA_DEL)
        && buf->b_p_bl
        && apply_autocmds(EVENT_BUFDELETE, buf->b_fname, buf->b_fname, false, buf)
        && !bufref_valid(&bufref)) {
      // Autocommands may delete the buffer.
      return;
    }
    if ((flags & BFA_WIPE)
        && apply_autocmds(EVENT_BUFWIPEOUT, buf->b_fname, buf->b_fname, false,
                          buf)
        && !bufref_valid(&bufref)) {
      // Autocommands may delete the buffer.
      return;
    }
    buf->b_locked--;
  
    // If the buffer was in curwin and the window has changed, go back to that
    // window, if it still exists.  This avoids that ":edit x" triggering a
    // "tabnext" BufUnload autocmd leaves a window behind without a buffer.
    if (is_curwin && curwin != the_curwin &&  win_valid_any_tab(the_curwin)) {
      block_autocmds();
      goto_tabpage_win(the_curtab, the_curwin);
      unblock_autocmds();
    }
    if (aborting()) {  // autocmds may abort script processing
      return;
    }
  
    /*
     * It's possible that autocommands change curbuf to the one being deleted.
     * This might cause curbuf to be deleted unexpectedly.  But in some cases
     * it's OK to delete the curbuf, because a new one is obtained anyway.
     * Therefore only return if curbuf changed to the deleted buffer.
     */
    if (buf == curbuf && !is_curbuf)
      return;
    diff_buf_delete(buf);             // Can't use 'diff' for unloaded buffer.
    // Remove any ownsyntax, unless exiting.
    if (curwin != NULL && curwin->w_buffer == buf) {
      reset_synblock(curwin);
    }
  
    /* No folds in an empty buffer. */
    FOR_ALL_TAB_WINDOWS(tp, win) {
      if (win->w_buffer == buf) {
        clearFolding(win);
      }
    }
  
    ml_close(buf, TRUE);              /* close and delete the memline/memfile */
    buf->b_ml.ml_line_count = 0;      /* no lines in buffer */
    if ((flags & BFA_KEEP_UNDO) == 0) {
      u_blockfree(buf);               /* free the memory allocated for undo */
      u_clearall(buf);                /* reset all undo information */
    }
    syntax_clear(&buf->b_s);          /* reset syntax info */
    buf->b_flags &= ~BF_READERR;      /* a read error is no longer relevant */
  }
  
  /*
   * Free a buffer structure and the things it contains related to the buffer
   * itself (not the file, that must have been done already).
   */
  static void free_buffer(buf_T *buf)
  {
    handle_unregister_buffer(buf);
    buf_free_count++;
    free_buffer_stuff(buf, true);
    unref_var_dict(buf->b_vars);
    aubuflocal_remove(buf);
    tv_dict_unref(buf->additional_data);
    clear_fmark(&buf->b_last_cursor);
    clear_fmark(&buf->b_last_insert);
    clear_fmark(&buf->b_last_change);
    for (size_t i = 0; i < NMARKS; i++) {
      free_fmark(buf->b_namedm[i]);
    }
    for (int i = 0; i < buf->b_changelistlen; i++) {
      free_fmark(buf->b_changelist[i]);
    }
    if (autocmd_busy) {
      // Do not free the buffer structure while autocommands are executing,
      // it's still needed. Free it when autocmd_busy is reset.
      memset(&buf->b_namedm[0], 0, sizeof(buf->b_namedm));
      memset(&buf->b_changelist[0], 0, sizeof(buf->b_changelist));
      buf->b_next = au_pending_free_buf;
      au_pending_free_buf = buf;
    } else {
      xfree(buf);
    }
  }
  
  /*
   * Free stuff in the buffer for ":bdel" and when wiping out the buffer.
   */
  static void 
  free_buffer_stuff (
      buf_T *buf,
      int free_options                       /* free options as well */
  )
  {
    if (free_options) {
      clear_wininfo(buf);                 // including window-local options
      free_buf_options(buf, true);
      ga_clear(&buf->b_s.b_langp);
    }
    {
      // Avoid loosing b:changedtick when deleting buffer: clearing variables
      // implies using clear_tv() on b:changedtick and that sets changedtick to
      // zero.
      hashitem_T *const changedtick_hi = hash_find(
          &buf->b_vars->dv_hashtab, (const char_u *)"changedtick");
      assert(changedtick_hi != NULL);
      hash_remove(&buf->b_vars->dv_hashtab, changedtick_hi);
    }
    vars_clear(&buf->b_vars->dv_hashtab);   // free all internal variables
    hash_init(&buf->b_vars->dv_hashtab);
    buf_init_changedtick(buf);
    uc_clear(&buf->b_ucmds);              // clear local user commands
    buf_delete_signs(buf);                // delete any signs
    bufhl_clear_all(buf);                // delete any highligts
    map_clear_int(buf, MAP_ALL_MODES, true, false);    // clear local mappings
    map_clear_int(buf, MAP_ALL_MODES, true, true);     // clear local abbrevs
    xfree(buf->b_start_fenc);
    buf->b_start_fenc = NULL;
  
    buf_updates_unregister_all(buf);
  }
  
  /*
   * Free the b_wininfo list for buffer "buf".
   */
  static void clear_wininfo(buf_T *buf)
  {
    wininfo_T   *wip;
  
    while (buf->b_wininfo != NULL) {
      wip = buf->b_wininfo;
      buf->b_wininfo = wip->wi_next;
      if (wip->wi_optset) {
        clear_winopt(&wip->wi_opt);
        deleteFoldRecurse(&wip->wi_folds);
      }
      xfree(wip);
    }
  }
  
  /*
   * Go to another buffer.  Handles the result of the ATTENTION dialog.
   */
  void goto_buffer(exarg_T *eap, int start, int dir, int count)
  {
    bufref_T old_curbuf;
    set_bufref(&old_curbuf, curbuf);
    swap_exists_action = SEA_DIALOG;
  
    (void)do_buffer(*eap->cmd == 's' ? DOBUF_SPLIT : DOBUF_GOTO,
                    start, dir, count, eap->forceit);
  
    if (swap_exists_action == SEA_QUIT && *eap->cmd == 's') {
      cleanup_T cs;
  
      /* Reset the error/interrupt/exception state here so that
       * aborting() returns FALSE when closing a window. */
      enter_cleanup(&cs);
  
      // Quitting means closing the split window, nothing else.
      win_close(curwin, true);
      swap_exists_action = SEA_NONE;
      swap_exists_did_quit = TRUE;
  
      /* Restore the error/interrupt/exception state if not discarded by a
       * new aborting error, interrupt, or uncaught exception. */
      leave_cleanup(&cs);
    } else {
      handle_swap_exists(&old_curbuf);
    }
  }
  
  /// Handle the situation of swap_exists_action being set.
  ///
  /// It is allowed for "old_curbuf" to be NULL or invalid.
  ///
  /// @param old_curbuf The buffer to check for.
  void handle_swap_exists(bufref_T *old_curbuf)
  {
    cleanup_T cs;
    long old_tw = curbuf->b_p_tw;
    buf_T *buf;
  
    if (swap_exists_action == SEA_QUIT) {
      /* Reset the error/interrupt/exception state here so that
       * aborting() returns FALSE when closing a buffer. */
      enter_cleanup(&cs);
  
      // User selected Quit at ATTENTION prompt.  Go back to previous
      // buffer.  If that buffer is gone or the same as the current one,
      // open a new, empty buffer.
      swap_exists_action = SEA_NONE;      // don't want it again
      swap_exists_did_quit = true;
      close_buffer(curwin, curbuf, DOBUF_UNLOAD, false);
      if (old_curbuf == NULL
          || !bufref_valid(old_curbuf)
          || old_curbuf->br_buf == curbuf) {
        buf = buflist_new(NULL, NULL, 1L, BLN_CURBUF | BLN_LISTED);
      } else {
        buf = old_curbuf->br_buf;
      }
      if (buf != NULL) {
        int old_msg_silent = msg_silent;
  
        if (shortmess(SHM_FILEINFO)) {
          msg_silent = 1;  // prevent fileinfo message
        }
        enter_buffer(buf);
        // restore msg_silent, so that the command line will be shown
        msg_silent = old_msg_silent;
  
        if (old_tw != curbuf->b_p_tw) {
          check_colorcolumn(curwin);
        }
      }
      /* If "old_curbuf" is NULL we are in big trouble here... */
  
      /* Restore the error/interrupt/exception state if not discarded by a
       * new aborting error, interrupt, or uncaught exception. */
      leave_cleanup(&cs);
    } else if (swap_exists_action == SEA_RECOVER) {
      /* Reset the error/interrupt/exception state here so that
       * aborting() returns FALSE when closing a buffer. */
      enter_cleanup(&cs);
  
      /* User selected Recover at ATTENTION prompt. */
      msg_scroll = TRUE;
      ml_recover();
      MSG_PUTS("\n");     /* don't overwrite the last message */
      cmdline_row = msg_row;
      do_modelines(0);
  
      /* Restore the error/interrupt/exception state if not discarded by a
       * new aborting error, interrupt, or uncaught exception. */
      leave_cleanup(&cs);
    }
    swap_exists_action = SEA_NONE;  // -V519
  }
  
  /*
   * do_bufdel() - delete or unload buffer(s)
   *
   * addr_count == 0: ":bdel" - delete current buffer
   * addr_count == 1: ":N bdel" or ":bdel N [N ..]" - first delete
   *		    buffer "end_bnr", then any other arguments.
   * addr_count == 2: ":N,N bdel" - delete buffers in range
   *
   * command can be DOBUF_UNLOAD (":bunload"), DOBUF_WIPE (":bwipeout") or
   * DOBUF_DEL (":bdel")
   *
   * Returns error message or NULL
   */
  char_u *
  do_bufdel (
      int command,
      char_u *arg,               /* pointer to extra arguments */
      int addr_count,
      int start_bnr,                  /* first buffer number in a range */
      int end_bnr,                    /* buffer nr or last buffer nr in a range */
      int forceit
  )
  {
    int do_current = 0;           /* delete current buffer? */
    int deleted = 0;              /* number of buffers deleted */
    char_u      *errormsg = NULL;   /* return value */
    int bnr;                      /* buffer number */
    char_u      *p;
  
    if (addr_count == 0) {
      (void)do_buffer(command, DOBUF_CURRENT, FORWARD, 0, forceit);
    } else {
      if (addr_count == 2) {
        if (*arg)                 /* both range and argument is not allowed */
          return (char_u *)_(e_trailing);
        bnr = start_bnr;
      } else      /* addr_count == 1 */
        bnr = end_bnr;
  
      for (; !got_int; os_breakcheck()) {
        /*
         * delete the current buffer last, otherwise when the
         * current buffer is deleted, the next buffer becomes
         * the current one and will be loaded, which may then
         * also be deleted, etc.
         */
        if (bnr == curbuf->b_fnum)
          do_current = bnr;
        else if (do_buffer(command, DOBUF_FIRST, FORWARD, bnr,
                     forceit) == OK)
          ++deleted;
  
        /*
         * find next buffer number to delete/unload
         */
        if (addr_count == 2) {
          if (++bnr > end_bnr)
            break;
        } else {    /* addr_count == 1 */
          arg = skipwhite(arg);
          if (*arg == NUL)
            break;
          if (!ascii_isdigit(*arg)) {
            p = skiptowhite_esc(arg);
            bnr = buflist_findpat(arg, p, command == DOBUF_WIPE,
                FALSE, FALSE);
            if (bnr < 0)                      /* failed */
              break;
            arg = p;
          } else
            bnr = getdigits_int(&arg);
        }
      }
      if (!got_int && do_current && do_buffer(command, DOBUF_FIRST,
              FORWARD, do_current, forceit) == OK)
        ++deleted;
  
      if (deleted == 0) {
        if (command == DOBUF_UNLOAD)
          STRCPY(IObuff, _("E515: No buffers were unloaded"));
        else if (command == DOBUF_DEL)
          STRCPY(IObuff, _("E516: No buffers were deleted"));
        else
          STRCPY(IObuff, _("E517: No buffers were wiped out"));
        errormsg = IObuff;
      } else if (deleted >= p_report) {
        if (command == DOBUF_UNLOAD) {
          if (deleted == 1)
            MSG(_("1 buffer unloaded"));
          else
            smsg(_("%d buffers unloaded"), deleted);
        } else if (command == DOBUF_DEL) {
          if (deleted == 1)
            MSG(_("1 buffer deleted"));
          else
            smsg(_("%d buffers deleted"), deleted);
        } else {
          if (deleted == 1)
            MSG(_("1 buffer wiped out"));
          else
            smsg(_("%d buffers wiped out"), deleted);
        }
      }
    }
  
  
    return errormsg;
  }
  
  
  
  /*
   * Make the current buffer empty.
   * Used when it is wiped out and it's the last buffer.
   */
  static int empty_curbuf(int close_others, int forceit, int action)
  {
    int retval;
    buf_T   *buf = curbuf;
  
    if (action == DOBUF_UNLOAD) {
      EMSG(_("E90: Cannot unload last buffer"));
      return FAIL;
    }
  
    bufref_T bufref;
    set_bufref(&bufref, buf);
  
    if (close_others) {
      /* Close any other windows on this buffer, then make it empty. */
      close_windows(buf, TRUE);
    }
  
    setpcmark();
    retval = do_ecmd(0, NULL, NULL, NULL, ECMD_ONE,
        forceit ? ECMD_FORCEIT : 0, curwin);
  
    // do_ecmd() may create a new buffer, then we have to delete
    // the old one.  But do_ecmd() may have done that already, check
    // if the buffer still exists.
    if (buf != curbuf && bufref_valid(&bufref) && buf->b_nwindows == 0) {
      close_buffer(NULL, buf, action, false);
    }
  
    if (!close_others) {
      need_fileinfo = false;
    }
  
    return retval;
  }
  /*
   * Implementation of the commands for the buffer list.
   *
   * action == DOBUF_GOTO	    go to specified buffer
   * action == DOBUF_SPLIT    split window and go to specified buffer
   * action == DOBUF_UNLOAD   unload specified buffer(s)
   * action == DOBUF_DEL	    delete specified buffer(s) from buffer list
   * action == DOBUF_WIPE	    delete specified buffer(s) really
   *
   * start == DOBUF_CURRENT   go to "count" buffer from current buffer
   * start == DOBUF_FIRST	    go to "count" buffer from first buffer
   * start == DOBUF_LAST	    go to "count" buffer from last buffer
   * start == DOBUF_MOD	    go to "count" modified buffer from current buffer
   *
   * Return FAIL or OK.
   */
  int 
  do_buffer (
      int action,
      int start,
      int dir,                        /* FORWARD or BACKWARD */
      int count,                      /* buffer number or number of buffers */
      int forceit                    /* TRUE for :...! */
  )
  {
    buf_T       *buf;
    buf_T       *bp;
    int unload = (action == DOBUF_UNLOAD || action == DOBUF_DEL
                  || action == DOBUF_WIPE);
  
    switch (start) {
    case DOBUF_FIRST:   buf = firstbuf; break;
    case DOBUF_LAST:    buf = lastbuf;  break;
    default:            buf = curbuf;   break;
    }
    if (start == DOBUF_MOD) {         /* find next modified buffer */
      while (count-- > 0) {
        do {
          buf = buf->b_next;
          if (buf == NULL)
            buf = firstbuf;
        } while (buf != curbuf && !bufIsChanged(buf));
      }
      if (!bufIsChanged(buf)) {
        EMSG(_("E84: No modified buffer found"));
        return FAIL;
      }
    } else if (start == DOBUF_FIRST && count) { /* find specified buffer number */
      while (buf != NULL && buf->b_fnum != count)
        buf = buf->b_next;
    } else {
      bp = NULL;
      while (count > 0 || (!unload && !buf->b_p_bl && bp != buf)) {
        /* remember the buffer where we start, we come back there when all
         * buffers are unlisted. */
        if (bp == NULL)
          bp = buf;
        if (dir == FORWARD) {
          buf = buf->b_next;
          if (buf == NULL)
            buf = firstbuf;
        } else {
          buf = buf->b_prev;
          if (buf == NULL)
            buf = lastbuf;
        }
        /* don't count unlisted buffers */
        if (unload || buf->b_p_bl) {
          --count;
          bp = NULL;              /* use this buffer as new starting point */
        }
        if (bp == buf) {
          /* back where we started, didn't find anything. */
          EMSG(_("E85: There is no listed buffer"));
          return FAIL;
        }
      }
    }
  
    if (buf == NULL) {        /* could not find it */
      if (start == DOBUF_FIRST) {
        // don't warn when deleting
        if (!unload) {
          EMSGN(_(e_nobufnr), count);
        }
      } else if (dir == FORWARD) {
        EMSG(_("E87: Cannot go beyond last buffer"));
      } else {
        EMSG(_("E88: Cannot go before first buffer"));
      }
      return FAIL;
    }
  
  
    /*
     * delete buffer buf from memory and/or the list
     */
    if (unload) {
      int forward;
      bufref_T bufref;
      set_bufref(&bufref, buf);
  
      /* When unloading or deleting a buffer that's already unloaded and
       * unlisted: fail silently. */
      if (action != DOBUF_WIPE && buf->b_ml.ml_mfp == NULL && !buf->b_p_bl)
        return FAIL;
  
      if (!forceit && (buf->terminal || bufIsChanged(buf))) {
        if ((p_confirm || cmdmod.confirm) && p_write && !buf->terminal) {
          dialog_changed(buf, false);
          if (!bufref_valid(&bufref)) {
            // Autocommand deleted buffer, oops! It's not changed now.
            return FAIL;
          }
          // If it's still changed fail silently, the dialog already
          // mentioned why it fails.
          if (bufIsChanged(buf)) {
            return FAIL;
          }
        } else {
          if (buf->terminal) {
            if (p_confirm || cmdmod.confirm) {
              if (!dialog_close_terminal(buf)) {
                return FAIL;
              }
            } else {
              EMSG2(_("E89: %s will be killed(add ! to override)"),
                    (char *)buf->b_fname);
              return FAIL;
            }
          } else {
            EMSGN(_("E89: No write since last change for buffer %" PRId64
                    " (add ! to override)"),
                  buf->b_fnum);
            return FAIL;
          }
        }
      }
  
      // When closing the current buffer stop Visual mode.
      if (buf == curbuf && VIsual_active) {
        end_visual_mode();
      }
  
      /*
       * If deleting the last (listed) buffer, make it empty.
       * The last (listed) buffer cannot be unloaded.
       */
      bp = NULL;
      FOR_ALL_BUFFERS(bp2) {
        if (bp2->b_p_bl && bp2 != buf) {
          bp = bp2;
          break;
        }
      }
      if (bp == NULL && buf == curbuf)
        return empty_curbuf(TRUE, forceit, action);
  
      /*
       * If the deleted buffer is the current one, close the current window
       * (unless it's the only window).  Repeat this so long as we end up in
       * a window with this buffer.
       */
      while (buf == curbuf
             && !(curwin->w_closing || curwin->w_buffer->b_locked > 0)
             && (!ONE_WINDOW || first_tabpage->tp_next != NULL)) {
        if (win_close(curwin, false) == FAIL)
          break;
      }
  
      /*
       * If the buffer to be deleted is not the current one, delete it here.
       */
      if (buf != curbuf) {
        close_windows(buf, false);
        if (buf != curbuf && bufref_valid(&bufref) && buf->b_nwindows <= 0) {
          close_buffer(NULL, buf, action, false);
        }
        return OK;
      }
  
      // Deleting the current buffer: Need to find another buffer to go to.
      // There should be another, otherwise it would have been handled
      // above.  However, autocommands may have deleted all buffers.
      // First use au_new_curbuf.br_buf, if it is valid.
      // Then prefer the buffer we most recently visited.
      // Else try to find one that is loaded, after the current buffer,
      // then before the current buffer.
      // Finally use any buffer.
      buf = NULL;  // Selected buffer.
      bp = NULL;   // Used when no loaded buffer found.
      if (au_new_curbuf.br_buf != NULL && bufref_valid(&au_new_curbuf)) {
        buf = au_new_curbuf.br_buf;
      } else if (curwin->w_jumplistlen > 0) {
        int jumpidx;
  
        jumpidx = curwin->w_jumplistidx - 1;
        if (jumpidx < 0)
          jumpidx = curwin->w_jumplistlen - 1;
  
        forward = jumpidx;
        while (jumpidx != curwin->w_jumplistidx) {
          buf = buflist_findnr(curwin->w_jumplist[jumpidx].fmark.fnum);
          if (buf != NULL) {
            if (buf == curbuf || !buf->b_p_bl)
              buf = NULL;                 /* skip current and unlisted bufs */
            else if (buf->b_ml.ml_mfp == NULL) {
              /* skip unloaded buf, but may keep it for later */
              if (bp == NULL)
                bp = buf;
              buf = NULL;
            }
          }
          if (buf != NULL)           /* found a valid buffer: stop searching */
            break;
          /* advance to older entry in jump list */
          if (!jumpidx && curwin->w_jumplistidx == curwin->w_jumplistlen)
            break;
          if (--jumpidx < 0)
            jumpidx = curwin->w_jumplistlen - 1;
          if (jumpidx == forward)                 /* List exhausted for sure */
            break;
        }
      }
  
      if (buf == NULL) {          /* No previous buffer, Try 2'nd approach */
        forward = TRUE;
        buf = curbuf->b_next;
        for (;; ) {
          if (buf == NULL) {
            if (!forward)                 /* tried both directions */
              break;
            buf = curbuf->b_prev;
            forward = FALSE;
            continue;
          }
          /* in non-help buffer, try to skip help buffers, and vv */
          if (buf->b_help == curbuf->b_help && buf->b_p_bl) {
            if (buf->b_ml.ml_mfp != NULL)             /* found loaded buffer */
              break;
            if (bp == NULL)               /* remember unloaded buf for later */
              bp = buf;
          }
          if (forward)
            buf = buf->b_next;
          else
            buf = buf->b_prev;
        }
      }
      if (buf == NULL)            /* No loaded buffer, use unloaded one */
        buf = bp;
      if (buf == NULL) {          /* No loaded buffer, find listed one */
        FOR_ALL_BUFFERS(buf2) {
          if (buf2->b_p_bl && buf2 != curbuf) {
            buf = buf2;
            break;
          }
        }
      }
      if (buf == NULL) {          /* Still no buffer, just take one */
        if (curbuf->b_next != NULL)
          buf = curbuf->b_next;
        else
          buf = curbuf->b_prev;
      }
    }
  
    if (buf == NULL) {
      /* Autocommands must have wiped out all other buffers.  Only option
       * now is to make the current buffer empty. */
      return empty_curbuf(FALSE, forceit, action);
    }
  
    /*
     * make buf current buffer
     */
    if (action == DOBUF_SPLIT) {      /* split window first */
      /* If 'switchbuf' contains "useopen": jump to first window containing
       * "buf" if one exists */
      if ((swb_flags & SWB_USEOPEN) && buf_jump_open_win(buf))
        return OK;
      /* If 'switchbuf' contains "usetab": jump to first window in any tab
       * page containing "buf" if one exists */
      if ((swb_flags & SWB_USETAB) && buf_jump_open_tab(buf))
        return OK;
      if (win_split(0, 0) == FAIL)
        return FAIL;
    }
  
    /* go to current buffer - nothing to do */
    if (buf == curbuf)
      return OK;
  
    /*
     * Check if the current buffer may be abandoned.
     */
    if (action == DOBUF_GOTO && !can_abandon(curbuf, forceit)) {
      if ((p_confirm || cmdmod.confirm) && p_write) {
        bufref_T bufref;
        set_bufref(&bufref, buf);
        dialog_changed(curbuf, false);
        if (!bufref_valid(&bufref)) {
          // Autocommand deleted buffer, oops!
          return FAIL;
        }
      }
      if (bufIsChanged(curbuf)) {
        EMSG(_(e_nowrtmsg));
        return FAIL;
      }
    }
  
    /* Go to the other buffer. */
    set_curbuf(buf, action);
  
    if (action == DOBUF_SPLIT) {
      RESET_BINDING(curwin);      /* reset 'scrollbind' and 'cursorbind' */
    }
  
    if (aborting())           /* autocmds may abort script processing */
      return FAIL;
  
    return OK;
  }
  
  
  /*
   * Set current buffer to "buf".  Executes autocommands and closes current
   * buffer.  "action" tells how to close the current buffer:
   * DOBUF_GOTO	    free or hide it
   * DOBUF_SPLIT	    nothing
   * DOBUF_UNLOAD	    unload it
   * DOBUF_DEL	    delete it
   * DOBUF_WIPE	    wipe it out
   */
  void set_curbuf(buf_T *buf, int action)
  {
    buf_T       *prevbuf;
    int unload = (action == DOBUF_UNLOAD || action == DOBUF_DEL
                  || action == DOBUF_WIPE);
    long old_tw = curbuf->b_p_tw;
  
    setpcmark();
    if (!cmdmod.keepalt)
      curwin->w_alt_fnum = curbuf->b_fnum;     /* remember alternate file */
    buflist_altfpos(curwin);                       /* remember curpos */
  
    /* Don't restart Select mode after switching to another buffer. */
    VIsual_reselect = FALSE;
  
    // close_windows() or apply_autocmds() may change curbuf and wipe out "buf"
    prevbuf = curbuf;
    bufref_T newbufref;
    bufref_T prevbufref;
    set_bufref(&prevbufref, prevbuf);
    set_bufref(&newbufref, buf);
  
    // Autocommands may delete the curren buffer and/or the buffer we wan to go
    // to.  In those cases don't close the buffer.
    if (!apply_autocmds(EVENT_BUFLEAVE, NULL, NULL, false, curbuf)
        || (bufref_valid(&prevbufref) && bufref_valid(&newbufref)
            && !aborting())) {
      if (prevbuf == curwin->w_buffer) {
        reset_synblock(curwin);
      }
      if (unload) {
        close_windows(prevbuf, false);
      }
      if (bufref_valid(&prevbufref) && !aborting()) {
        win_T  *previouswin = curwin;
        if (prevbuf == curbuf) {
          u_sync(false);
        }
        close_buffer(prevbuf == curwin->w_buffer ? curwin : NULL,
                     prevbuf,
                     unload
                     ? action
                     : (action == DOBUF_GOTO && !buf_hide(prevbuf)
                        && !bufIsChanged(prevbuf)) ? DOBUF_UNLOAD : 0,
                     false);
        if (curwin != previouswin && win_valid(previouswin)) {
          // autocommands changed curwin, Grr!
          curwin = previouswin;
        }
      }
    }
    /* An autocommand may have deleted "buf", already entered it (e.g., when
     * it did ":bunload") or aborted the script processing!
     * If curwin->w_buffer is null, enter_buffer() will make it valid again */
    if ((buf_valid(buf) && buf != curbuf
         && !aborting()
         ) || curwin->w_buffer == NULL
        ) {
      enter_buffer(buf);
      if (old_tw != curbuf->b_p_tw)
        check_colorcolumn(curwin);
    }
  }
  
  /*
   * Enter a new current buffer.
   * Old curbuf must have been abandoned already!  This also means "curbuf" may
   * be pointing to freed memory.
   */
  void enter_buffer(buf_T *buf)
  {
    /* Copy buffer and window local option values.  Not for a help buffer. */
    buf_copy_options(buf, BCO_ENTER | BCO_NOHELP);
    if (!buf->b_help)
      get_winopts(buf);
    else
      /* Remove all folds in the window. */
      clearFolding(curwin);
    foldUpdateAll(curwin);        /* update folds (later). */
  
    /* Get the buffer in the current window. */
    curwin->w_buffer = buf;
    curbuf = buf;
    ++curbuf->b_nwindows;
  
    if (curwin->w_p_diff)
      diff_buf_add(curbuf);
  
    curwin->w_s = &(buf->b_s);
  
    /* Cursor on first line by default. */
    curwin->w_cursor.lnum = 1;
    curwin->w_cursor.col = 0;
    curwin->w_cursor.coladd = 0;
    curwin->w_set_curswant = TRUE;
    curwin->w_topline_was_set = FALSE;
  
    /* mark cursor position as being invalid */
    curwin->w_valid = 0;
  
    /* Make sure the buffer is loaded. */
    if (curbuf->b_ml.ml_mfp == NULL) {    /* need to load the file */
      /* If there is no filetype, allow for detecting one.  Esp. useful for
       * ":ball" used in an autocommand.  If there already is a filetype we
       * might prefer to keep it. */
      if (*curbuf->b_p_ft == NUL)
        did_filetype = FALSE;
  
      open_buffer(FALSE, NULL, 0);
    } else {
      if (!msg_silent)
        need_fileinfo = TRUE;             /* display file info after redraw */
      (void)buf_check_timestamp(curbuf, FALSE);     /* check if file changed */
      curwin->w_topline = 1;
      curwin->w_topfill = 0;
      apply_autocmds(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf);
      apply_autocmds(EVENT_BUFWINENTER, NULL, NULL, FALSE, curbuf);
    }
  
    /* If autocommands did not change the cursor position, restore cursor lnum
     * and possibly cursor col. */
    if (curwin->w_cursor.lnum == 1 && inindent(0))
      buflist_getfpos();
  
    check_arg_idx(curwin);                /* check for valid arg_idx */
    maketitle();
    /* when autocmds didn't change it */
    if (curwin->w_topline == 1 && !curwin->w_topline_was_set)
      scroll_cursor_halfway(FALSE);       /* redisplay at correct position */
  
  
    /* Change directories when the 'acd' option is set. */
    do_autochdir();
  
    if (curbuf->b_kmap_state & KEYMAP_INIT)
      (void)keymap_init();
    /* May need to set the spell language.  Can only do this after the buffer
     * has been properly setup. */
    if (!curbuf->b_help && curwin->w_p_spell && *curwin->w_s->b_p_spl != NUL)
      (void)did_set_spelllang(curwin);
  
    redraw_later(NOT_VALID);
  }
  
  // Change to the directory of the current buffer.
  // Don't do this while still starting up.
  void do_autochdir(void)
  {
    if (p_acd) {
      if (starting == 0
          && curbuf->b_ffname != NULL
          && vim_chdirfile(curbuf->b_ffname) == OK) {
        shorten_fnames(true);
      }
    }
  }
  
  //
  // functions for dealing with the buffer list
  //
  
  static int top_file_num = 1;            ///< highest file number
  
  /// Initialize b:changedtick and changedtick_val attribute
  ///
  /// @param[out]  buf  Buffer to intialize for.
  static inline void buf_init_changedtick(buf_T *const buf)
    FUNC_ATTR_ALWAYS_INLINE FUNC_ATTR_NONNULL_ALL
  {
    STATIC_ASSERT(sizeof("changedtick") <= sizeof(buf->changedtick_di.di_key),
                  "buf->changedtick_di cannot hold large enough keys");
    buf->changedtick_di = (ChangedtickDictItem) {
      .di_flags = DI_FLAGS_RO|DI_FLAGS_FIX,  // Must not include DI_FLAGS_ALLOC.
      .di_tv = (typval_T) {
        .v_type = VAR_NUMBER,
        .v_lock = VAR_FIXED,
        .vval.v_number = buf_get_changedtick(buf),
      },
      .di_key = "changedtick",
    };
    tv_dict_add(buf->b_vars, (dictitem_T *)&buf->changedtick_di);
  }
  
  /// Add a file name to the buffer list.
  /// If the same file name already exists return a pointer to that buffer.
  /// If it does not exist, or if fname == NULL, a new entry is created.
  /// If (flags & BLN_CURBUF) is TRUE, may use current buffer.
  /// If (flags & BLN_LISTED) is TRUE, add new buffer to buffer list.
  /// If (flags & BLN_DUMMY) is TRUE, don't count it as a real buffer.
  /// If (flags & BLN_NEW) is TRUE, don't use an existing buffer.
  /// If (flags & BLN_NOOPT) is TRUE, don't copy options from the current buffer
  ///                                 if the buffer already exists.
  /// This is the ONLY way to create a new buffer.
  ///
  /// @param ffname full path of fname or relative
  /// @param sfname short fname or NULL
  /// @param lnum   preferred cursor line
  /// @param flags  BLN_ defines
  /// @param bufnr
  ///
  /// @return pointer to the buffer
  buf_T * buflist_new(char_u *ffname, char_u *sfname, linenr_T lnum, int flags)
  {
    buf_T       *buf;
  
    fname_expand(curbuf, &ffname, &sfname);       // will allocate ffname
  
    /*
     * If file name already exists in the list, update the entry.
     */
    /* We can use inode numbers when the file exists.  Works better
     * for hard links. */
    FileID file_id;
    bool file_id_valid = (sfname != NULL
                          && os_fileid((char *)sfname, &file_id));
    if (ffname != NULL && !(flags & BLN_DUMMY)
        && (buf = buflist_findname_file_id(ffname, &file_id,
                                           file_id_valid)) != NULL) {
      xfree(ffname);
      if (lnum != 0) {
        buflist_setfpos(buf, curwin, lnum, (colnr_T)0, false);
      }
      if ((flags & BLN_NOOPT) == 0) {
        // Copy the options now, if 'cpo' doesn't have 's' and not done already.
        buf_copy_options(buf, 0);
      }
      if ((flags & BLN_LISTED) && !buf->b_p_bl) {
        buf->b_p_bl = true;
        bufref_T bufref;
        set_bufref(&bufref, buf);
        if (!(flags & BLN_DUMMY)) {
          if (apply_autocmds(EVENT_BUFADD, NULL, NULL, false, buf)
              && !bufref_valid(&bufref)) {
            return NULL;
          }
        }
      }
      return buf;
    }
  
    /*
     * If the current buffer has no name and no contents, use the current
     * buffer.	Otherwise: Need to allocate a new buffer structure.
     *
     * This is the ONLY place where a new buffer structure is allocated!
     * (A spell file buffer is allocated in spell.c, but that's not a normal
     * buffer.)
     */
    buf = NULL;
    if ((flags & BLN_CURBUF)
        && curbuf != NULL
        && curbuf->b_ffname == NULL
        && curbuf->b_nwindows <= 1
        && (curbuf->b_ml.ml_mfp == NULL || BUFEMPTY())) {
      buf = curbuf;
      /* It's like this buffer is deleted.  Watch out for autocommands that
       * change curbuf!  If that happens, allocate a new buffer anyway. */
      if (curbuf->b_p_bl)
        apply_autocmds(EVENT_BUFDELETE, NULL, NULL, FALSE, curbuf);
      if (buf == curbuf)
        apply_autocmds(EVENT_BUFWIPEOUT, NULL, NULL, FALSE, curbuf);
      if (aborting())             /* autocmds may abort script processing */
        return NULL;
      if (buf == curbuf) {
        /* Make sure 'bufhidden' and 'buftype' are empty */
        clear_string_option(&buf->b_p_bh);
        clear_string_option(&buf->b_p_bt);
      }
    }
    if (buf != curbuf || curbuf == NULL) {
      buf = xcalloc(1, sizeof(buf_T));
      // init b: variables
      buf->b_vars = tv_dict_alloc();
      init_var_dict(buf->b_vars, &buf->b_bufvar, VAR_SCOPE);
      buf_init_changedtick(buf);
    }
  
    if (ffname != NULL) {
      buf->b_ffname = ffname;
      buf->b_sfname = vim_strsave(sfname);
    }
  
    clear_wininfo(buf);
    buf->b_wininfo = xcalloc(1, sizeof(wininfo_T));
  
    if (ffname != NULL && (buf->b_ffname == NULL || buf->b_sfname == NULL)) {
      xfree(buf->b_ffname);
      buf->b_ffname = NULL;
      xfree(buf->b_sfname);
      buf->b_sfname = NULL;
      if (buf != curbuf)
        free_buffer(buf);
      return NULL;
    }
  
    if (buf == curbuf) {
      /* free all things allocated for this buffer */
      buf_freeall(buf, 0);
      if (buf != curbuf)           /* autocommands deleted the buffer! */
        return NULL;
      if (aborting())             /* autocmds may abort script processing */
        return NULL;
      free_buffer_stuff(buf, FALSE);      /* delete local variables et al. */
  
      /* Init the options. */
      buf->b_p_initialized = false;
      buf_copy_options(buf, BCO_ENTER);
  
      /* need to reload lmaps and set b:keymap_name */
      curbuf->b_kmap_state |= KEYMAP_INIT;
    } else {
      /*
       * put new buffer at the end of the buffer list
       */
      buf->b_next = NULL;
      if (firstbuf == NULL) {             /* buffer list is empty */
        buf->b_prev = NULL;
        firstbuf = buf;
      } else {                          /* append new buffer at end of list */
        lastbuf->b_next = buf;
        buf->b_prev = lastbuf;
      }
      lastbuf = buf;
  
      buf->b_fnum = top_file_num++;
      handle_register_buffer(buf);
      if (top_file_num < 0) {  // wrap around (may cause duplicates)
        EMSG(_("W14: Warning: List of file names overflow"));
        if (emsg_silent == 0) {
          ui_flush();
          os_delay(3000L, true);  // make sure it is noticed
        }
        top_file_num = 1;
      }
  
      /*
       * Always copy the options from the current buffer.
       */
      buf_copy_options(buf, BCO_ALWAYS);
    }
  
    buf->b_wininfo->wi_fpos.lnum = lnum;
    buf->b_wininfo->wi_win = curwin;
  
    hash_init(&buf->b_s.b_keywtab);
    hash_init(&buf->b_s.b_keywtab_ic);
  
    buf->b_fname = buf->b_sfname;
    if (!file_id_valid) {
      buf->file_id_valid = false;
    } else {
      buf->file_id_valid = true;
      buf->file_id = file_id;
    }
    buf->b_u_synced = true;
    buf->b_flags = BF_CHECK_RO | BF_NEVERLOADED;
    if (flags & BLN_DUMMY)
      buf->b_flags |= BF_DUMMY;
    buf_clear_file(buf);
    clrallmarks(buf);                     // clear marks
    fmarks_check_names(buf);              // check file marks for this file
    buf->b_p_bl = (flags & BLN_LISTED) ? true : false;    // init 'buflisted'
    kv_destroy(buf->update_channels);
    kv_init(buf->update_channels);
    if (!(flags & BLN_DUMMY)) {
      // Tricky: these autocommands may change the buffer list.  They could also
      // split the window with re-using the one empty buffer. This may result in
      // unexpectedly losing the empty buffer.
      bufref_T bufref;
      set_bufref(&bufref, buf);
      if (apply_autocmds(EVENT_BUFNEW, NULL, NULL, false, buf)
          && !bufref_valid(&bufref)) {
        return NULL;
      }
      if ((flags & BLN_LISTED)
          && apply_autocmds(EVENT_BUFADD, NULL, NULL, false, buf)
          && !bufref_valid(&bufref)) {
        return NULL;
      }
      if (aborting()) {
        // Autocmds may abort script processing.
        return NULL;
      }
    }
  
    return buf;
  }
  
  /*
   * Free the memory for the options of a buffer.
   * If "free_p_ff" is TRUE also free 'fileformat', 'buftype' and
   * 'fileencoding'.
   */
  void free_buf_options(buf_T *buf, int free_p_ff)
  {
    if (free_p_ff) {
      clear_string_option(&buf->b_p_fenc);
      clear_string_option(&buf->b_p_ff);
      clear_string_option(&buf->b_p_bh);
      clear_string_option(&buf->b_p_bt);
    }
    clear_string_option(&buf->b_p_def);
    clear_string_option(&buf->b_p_inc);
    clear_string_option(&buf->b_p_inex);
    clear_string_option(&buf->b_p_inde);
    clear_string_option(&buf->b_p_indk);
    clear_string_option(&buf->b_p_fp);
    clear_string_option(&buf->b_p_fex);
    clear_string_option(&buf->b_p_kp);
    clear_string_option(&buf->b_p_mps);
    clear_string_option(&buf->b_p_fo);
    clear_string_option(&buf->b_p_flp);
    clear_string_option(&buf->b_p_isk);
    clear_string_option(&buf->b_p_keymap);
    keymap_ga_clear(&buf->b_kmap_ga);
    ga_clear(&buf->b_kmap_ga);
    clear_string_option(&buf->b_p_com);
    clear_string_option(&buf->b_p_cms);
    clear_string_option(&buf->b_p_nf);
    clear_string_option(&buf->b_p_syn);
    clear_string_option(&buf->b_s.b_syn_isk);
    clear_string_option(&buf->b_s.b_p_spc);
    clear_string_option(&buf->b_s.b_p_spf);
    vim_regfree(buf->b_s.b_cap_prog);
    buf->b_s.b_cap_prog = NULL;
    clear_string_option(&buf->b_s.b_p_spl);
    clear_string_option(&buf->b_p_sua);
    clear_string_option(&buf->b_p_ft);
    clear_string_option(&buf->b_p_cink);
    clear_string_option(&buf->b_p_cino);
    clear_string_option(&buf->b_p_cinw);
    clear_string_option(&buf->b_p_cpt);
    clear_string_option(&buf->b_p_cfu);
    clear_string_option(&buf->b_p_ofu);
    clear_string_option(&buf->b_p_gp);
    clear_string_option(&buf->b_p_mp);
    clear_string_option(&buf->b_p_efm);
    clear_string_option(&buf->b_p_ep);
    clear_string_option(&buf->b_p_path);
    clear_string_option(&buf->b_p_tags);
    clear_string_option(&buf->b_p_tc);
    clear_string_option(&buf->b_p_dict);
    clear_string_option(&buf->b_p_tsr);
    clear_string_option(&buf->b_p_qe);
    buf->b_p_ar = -1;
    buf->b_p_ul = NO_LOCAL_UNDOLEVEL;
    clear_string_option(&buf->b_p_lw);
    clear_string_option(&buf->b_p_bkc);
    clear_string_option(&buf->b_p_menc);
  }
  
  
  /// Get alternate file "n".
  /// Set linenr to "lnum" or altfpos.lnum if "lnum" == 0.
  /// Also set cursor column to altfpos.col if 'startofline' is not set.
  /// if (options & GETF_SETMARK) call setpcmark()
  /// if (options & GETF_ALT) we are jumping to an alternate file.
  /// if (options & GETF_SWITCH) respect 'switchbuf' settings when jumping
  ///
  /// Return FAIL for failure, OK for success.
  int buflist_getfile(int n, linenr_T lnum, int options, int forceit)
  {
    buf_T       *buf;
    win_T       *wp = NULL;
    pos_T       *fpos;
    colnr_T col;
  
    buf = buflist_findnr(n);
    if (buf == NULL) {
      if ((options & GETF_ALT) && n == 0)
        EMSG(_(e_noalt));
      else
        EMSGN(_("E92: Buffer %" PRId64 " not found"), n);
      return FAIL;
    }
  
    /* if alternate file is the current buffer, nothing to do */
    if (buf == curbuf)
      return OK;
  
    if (text_locked()) {
      text_locked_msg();
      return FAIL;
    }
    if (curbuf_locked())
      return FAIL;
  
    /* altfpos may be changed by getfile(), get it now */
    if (lnum == 0) {
      fpos = buflist_findfpos(buf);
      lnum = fpos->lnum;
      col = fpos->col;
    } else
      col = 0;
  
    if (options & GETF_SWITCH) {
      // If 'switchbuf' contains "useopen": jump to first window containing
      // "buf" if one exists
      if (swb_flags & SWB_USEOPEN) {
        wp = buf_jump_open_win(buf);
      }
  
      // If 'switchbuf' contains "usetab": jump to first window in any tab
      // page containing "buf" if one exists
      if (wp == NULL && (swb_flags & SWB_USETAB)) {
        wp = buf_jump_open_tab(buf);
      }
  
      // If 'switchbuf' contains "split", "vsplit" or "newtab" and the
      // current buffer isn't empty: open new tab or window
      if (wp == NULL && (swb_flags & (SWB_VSPLIT | SWB_SPLIT | SWB_NEWTAB))
          && !BUFEMPTY()) {
        if (swb_flags & SWB_NEWTAB) {
          tabpage_new();
        } else if (win_split(0, (swb_flags & SWB_VSPLIT) ? WSP_VERT : 0)
                   == FAIL) {
          return FAIL;
        }
        RESET_BINDING(curwin);
      }
    }
  
    RedrawingDisabled++;
    if (GETFILE_SUCCESS(getfile(buf->b_fnum, NULL, NULL,
                                (options & GETF_SETMARK), lnum, forceit))) {
      RedrawingDisabled--;
  
      /* cursor is at to BOL and w_cursor.lnum is checked due to getfile() */
      if (!p_sol && col != 0) {
        curwin->w_cursor.col = col;
        check_cursor_col();
        curwin->w_cursor.coladd = 0;
        curwin->w_set_curswant = TRUE;
      }
      return OK;
    }
    RedrawingDisabled--;
    return FAIL;
  }
  
  // Go to the last known line number for the current buffer.
  void buflist_getfpos(void)
  {
    pos_T       *fpos;
  
    fpos = buflist_findfpos(curbuf);
  
    curwin->w_cursor.lnum = fpos->lnum;
    check_cursor_lnum();
  
    if (p_sol)
      curwin->w_cursor.col = 0;
    else {
      curwin->w_cursor.col = fpos->col;
      check_cursor_col();
      curwin->w_cursor.coladd = 0;
      curwin->w_set_curswant = TRUE;
    }
  }
  
  /*
   * Find file in buffer list by name (it has to be for the current window).
   * Returns NULL if not found.
   */
  buf_T *buflist_findname_exp(char_u *fname)
  {
    char_u      *ffname;
    buf_T       *buf = NULL;
  
    /* First make the name into a full path name */
    ffname = (char_u *)FullName_save((char *)fname,
  #ifdef UNIX
        TRUE                  /* force expansion, get rid of symbolic links */
  #else
        FALSE
  #endif
        );
    if (ffname != NULL) {
      buf = buflist_findname(ffname);
      xfree(ffname);
    }
    return buf;
  }
  
  /*
   * Find file in buffer list by name (it has to be for the current window).
   * "ffname" must have a full path.
   * Skips dummy buffers.
   * Returns NULL if not found.
   */
  buf_T *buflist_findname(char_u *ffname)
  {
    FileID file_id;
    bool file_id_valid = os_fileid((char *)ffname, &file_id);
    return buflist_findname_file_id(ffname, &file_id, file_id_valid);
  }
  
  /*
   * Same as buflist_findname(), but pass the FileID structure to avoid
   * getting it twice for the same file.
   * Returns NULL if not found.
   */
  static buf_T *buflist_findname_file_id(char_u *ffname, FileID *file_id,
                                         bool file_id_valid)
  {
    // Start at the last buffer, expect to find a match sooner.
    FOR_ALL_BUFFERS_BACKWARDS(buf) {
      if ((buf->b_flags & BF_DUMMY) == 0
          && !otherfile_buf(buf, ffname, file_id, file_id_valid)) {
        return buf;
      }
    }
    return NULL;
  }
  
  /// Find file in buffer list by a regexp pattern.
  /// Return fnum of the found buffer.
  /// Return < 0 for error.
  int buflist_findpat(
      const char_u *pattern,
      const char_u *pattern_end,  // pointer to first char after pattern
      int unlisted,               // find unlisted buffers
      int diffmode,               // find diff-mode buffers only
      int curtab_only             // find buffers in current tab only
  )
  {
    int match = -1;
    int find_listed;
    char_u      *pat;
    char_u      *patend;
    int attempt;
    char_u      *p;
    int toggledollar;
  
    if (pattern_end == pattern + 1 && (*pattern == '%' || *pattern == '#')) {
      if (*pattern == '%') {
        match = curbuf->b_fnum;
      } else {
        match = curwin->w_alt_fnum;
      }
      buf_T *found_buf = buflist_findnr(match);
      if (diffmode && !(found_buf && diff_mode_buf(found_buf))) {
        match = -1;
      }
    }
    /*
     * Try four ways of matching a listed buffer:
     * attempt == 0: without '^' or '$' (at any position)
     * attempt == 1: with '^' at start (only at position 0)
     * attempt == 2: with '$' at end (only match at end)
     * attempt == 3: with '^' at start and '$' at end (only full match)
     * Repeat this for finding an unlisted buffer if there was no matching
     * listed buffer.
     */
    else {
      pat = file_pat_to_reg_pat(pattern, pattern_end, NULL, FALSE);
      if (pat == NULL)
        return -1;
      patend = pat + STRLEN(pat) - 1;
      toggledollar = (patend > pat && *patend == '$');
  
      /* First try finding a listed buffer.  If not found and "unlisted"
       * is TRUE, try finding an unlisted buffer. */
      find_listed = TRUE;
      for (;; ) {
        for (attempt = 0; attempt <= 3; ++attempt) {
          /* may add '^' and '$' */
          if (toggledollar)
            *patend = (attempt < 2) ? NUL : '$';           /* add/remove '$' */
          p = pat;
          if (*p == '^' && !(attempt & 1))                 /* add/remove '^' */
            ++p;
  
          regmatch_T regmatch;
          regmatch.regprog = vim_regcomp(p, p_magic ? RE_MAGIC : 0);
          if (regmatch.regprog == NULL) {
            xfree(pat);
            return -1;
          }
  
          FOR_ALL_BUFFERS_BACKWARDS(buf) {
            if (buf->b_p_bl == find_listed
                && (!diffmode || diff_mode_buf(buf))
                && buflist_match(&regmatch, buf, false) != NULL) {
              if (curtab_only) {
                /* Ignore the match if the buffer is not open in
                 * the current tab. */
                bool found_window = false;
                FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
                  if (wp->w_buffer == buf) {
                    found_window = true;
                    break;
                  }
                }
                if (!found_window) {
                  continue;
                }
              }
              if (match >= 0) {                   /* already found a match */
                match = -2;
                break;
              }
              match = buf->b_fnum;                /* remember first match */
            }
          }
  
          vim_regfree(regmatch.regprog);
          if (match >= 0)                         /* found one match */
            break;
        }
  
        /* Only search for unlisted buffers if there was no match with
         * a listed buffer. */
        if (!unlisted || !find_listed || match != -1)
          break;
        find_listed = FALSE;
      }
  
      xfree(pat);
    }
  
    if (match == -2)
      EMSG2(_("E93: More than one match for %s"), pattern);
    else if (match < 0)
      EMSG2(_("E94: No matching buffer for %s"), pattern);
    return match;
  }
  
  
  /*
   * Find all buffer names that match.
   * For command line expansion of ":buf" and ":sbuf".
   * Return OK if matches found, FAIL otherwise.
   */
  int ExpandBufnames(char_u *pat, int *num_file, char_u ***file, int options)
  {
    int count = 0;
    int round;
    char_u      *p;
    int attempt;
    char_u      *patc;
  
    *num_file = 0;                    /* return values in case of FAIL */
    *file = NULL;
  
    /* Make a copy of "pat" and change "^" to "\(^\|[\/]\)". */
    if (*pat == '^') {
      patc = xmalloc(STRLEN(pat) + 11);
      STRCPY(patc, "\\(^\\|[\\/]\\)");
      STRCPY(patc + 11, pat + 1);
    } else
      patc = pat;
  
    /*
     * attempt == 0: try match with    '\<', match at start of word
     * attempt == 1: try match without '\<', match anywhere
     */
    for (attempt = 0; attempt <= 1; ++attempt) {
      if (attempt > 0 && patc == pat)
        break;            /* there was no anchor, no need to try again */
  
      regmatch_T regmatch;
      regmatch.regprog = vim_regcomp(patc + attempt * 11, RE_MAGIC);
      if (regmatch.regprog == NULL) {
        if (patc != pat)
          xfree(patc);
        return FAIL;
      }
  
      /*
       * round == 1: Count the matches.
       * round == 2: Build the array to keep the matches.
       */
      for (round = 1; round <= 2; ++round) {
        count = 0;
        FOR_ALL_BUFFERS(buf) {
          if (!buf->b_p_bl)               /* skip unlisted buffers */
            continue;
          p = buflist_match(&regmatch, buf, p_wic);
          if (p != NULL) {
            if (round == 1)
              ++count;
            else {
              if (options & WILD_HOME_REPLACE)
                p = home_replace_save(buf, p);
              else
                p = vim_strsave(p);
              (*file)[count++] = p;
            }
          }
        }
        if (count == 0)           /* no match found, break here */
          break;
        if (round == 1) {
          *file = xmalloc((size_t)count * sizeof(**file));
        }
      }
      vim_regfree(regmatch.regprog);
      if (count)                  /* match(es) found, break here */
        break;
    }
  
    if (patc != pat)
      xfree(patc);
  
    *num_file = count;
    return count == 0 ? FAIL : OK;
  }
  
  
  /// Check for a match on the file name for buffer "buf" with regprog "prog".
  ///
  /// @param ignore_case When TRUE, ignore case. Use 'fic' otherwise.
  static char_u *buflist_match(regmatch_T *rmp, buf_T *buf, bool ignore_case)
  {
    // First try the short file name, then the long file name.
    char_u *match = fname_match(rmp, buf->b_sfname, ignore_case);
    if (match == NULL) {
      match = fname_match(rmp, buf->b_ffname, ignore_case);
    }
    return match;
  }
  
  /// Try matching the regexp in "prog" with file name "name".
  ///
  /// @param ignore_case When TRUE, ignore case. Use 'fileignorecase' otherwise.
  /// @return "name" when there is a match, NULL when not.
  static char_u *fname_match(regmatch_T *rmp, char_u *name, bool ignore_case)
  {
    char_u      *match = NULL;
    char_u      *p;
  
    if (name != NULL) {
      // Ignore case when 'fileignorecase' or the argument is set.
      rmp->rm_ic = p_fic || ignore_case;
      if (vim_regexec(rmp, name, (colnr_T)0))
        match = name;
      else {
        /* Replace $(HOME) with '~' and try matching again. */
        p = home_replace_save(NULL, name);
        if (vim_regexec(rmp, p, (colnr_T)0))
          match = name;
        xfree(p);
      }
    }
  
    return match;
  }
  
  /// Find a file in the buffer list by buffer number.
  buf_T *buflist_findnr(int nr)
  {
    if (nr == 0) {
      nr = curwin->w_alt_fnum;
    }
  
    return handle_get_buffer((handle_T)nr);
  }
  
  /*
   * Get name of file 'n' in the buffer list.
   * When the file has no name an empty string is returned.
   * home_replace() is used to shorten the file name (used for marks).
   * Returns a pointer to allocated memory, of NULL when failed.
   */
  char_u *
  buflist_nr2name (
      int n,
      int fullname,
      int helptail                   /* for help buffers return tail only */
  )
  {
    buf_T       *buf;
  
    buf = buflist_findnr(n);
    if (buf == NULL)
      return NULL;
    return home_replace_save(helptail ? buf : NULL,
        fullname ? buf->b_ffname : buf->b_fname);
  }
  
  /// Set the line and column numbers for the given buffer and window
  ///
  /// @param[in,out]  buf           Buffer for which line and column are set.
  /// @param[in,out]  win           Window for which line and column are set.
  /// @param[in]      lnum          Line number to be set. If it is zero then only
  ///                               options are touched.
  /// @param[in]      col           Column number to be set.
  /// @param[in]      copy_options  If true save the local window option values.
  void buflist_setfpos(buf_T *const buf, win_T *const win,
                       linenr_T lnum, colnr_T col,
                       bool copy_options)
    FUNC_ATTR_NONNULL_ALL
  {
    wininfo_T   *wip;
  
    for (wip = buf->b_wininfo; wip != NULL; wip = wip->wi_next)
      if (wip->wi_win == win)
        break;
    if (wip == NULL) {
      /* allocate a new entry */
      wip = xcalloc(1, sizeof(wininfo_T));
      wip->wi_win = win;
      if (lnum == 0)              /* set lnum even when it's 0 */
        lnum = 1;
    } else {
      /* remove the entry from the list */
      if (wip->wi_prev)
        wip->wi_prev->wi_next = wip->wi_next;
      else
        buf->b_wininfo = wip->wi_next;
      if (wip->wi_next)
        wip->wi_next->wi_prev = wip->wi_prev;
      if (copy_options && wip->wi_optset) {
        clear_winopt(&wip->wi_opt);
        deleteFoldRecurse(&wip->wi_folds);
      }
    }
    if (lnum != 0) {
      wip->wi_fpos.lnum = lnum;
      wip->wi_fpos.col = col;
    }
    if (copy_options) {
      /* Save the window-specific option values. */
      copy_winopt(&win->w_onebuf_opt, &wip->wi_opt);
      wip->wi_fold_manual = win->w_fold_manual;
      cloneFoldGrowArray(&win->w_folds, &wip->wi_folds);
      wip->wi_optset = true;
    }
  
    /* insert the entry in front of the list */
    wip->wi_next = buf->b_wininfo;
    buf->b_wininfo = wip;
    wip->wi_prev = NULL;
    if (wip->wi_next)
      wip->wi_next->wi_prev = wip;
  
    return;
  }
  
  
  /// Check that "wip" has 'diff' set and the diff is only for another tab page.
  /// That's because a diff is local to a tab page.
  static bool wininfo_other_tab_diff(wininfo_T *wip)
    FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_NONNULL_ALL
  {
    if (wip->wi_opt.wo_diff) {
      FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
        // return false when it's a window in the current tab page, thus
        // the buffer was in diff mode here
        if (wip->wi_win == wp) {
          return false;
        }
      }
      return true;
    }
    return false;
  }
  
  /*
   * Find info for the current window in buffer "buf".
   * If not found, return the info for the most recently used window.
   * When "skip_diff_buffer" is TRUE avoid windows with 'diff' set that is in
   * another tab page.
   * Returns NULL when there isn't any info.
   */
  static wininfo_T *find_wininfo(buf_T *buf, int skip_diff_buffer)
  {
    wininfo_T   *wip;
  
    for (wip = buf->b_wininfo; wip != NULL; wip = wip->wi_next)
      if (wip->wi_win == curwin
          && (!skip_diff_buffer || !wininfo_other_tab_diff(wip))
          )
        break;
  
    /* If no wininfo for curwin, use the first in the list (that doesn't have
     * 'diff' set and is in another tab page). */
    if (wip == NULL) {
      if (skip_diff_buffer) {
        for (wip = buf->b_wininfo; wip != NULL; wip = wip->wi_next)
          if (!wininfo_other_tab_diff(wip))
            break;
      } else
        wip = buf->b_wininfo;
    }
    return wip;
  }
  
  /*
   * Reset the local window options to the values last used in this window.
   * If the buffer wasn't used in this window before, use the values from
   * the most recently used window.  If the values were never set, use the
   * global values for the window.
   */
  void get_winopts(buf_T *buf)
  {
    wininfo_T   *wip;
  
    clear_winopt(&curwin->w_onebuf_opt);
    clearFolding(curwin);
  
    wip = find_wininfo(buf, true);
    if (wip != NULL && wip->wi_win != curwin && wip->wi_win != NULL
        && wip->wi_win->w_buffer == buf) {
      win_T *wp = wip->wi_win;
      copy_winopt(&wp->w_onebuf_opt, &curwin->w_onebuf_opt);
      curwin->w_fold_manual = wp->w_fold_manual;
      curwin->w_foldinvalid = true;
      cloneFoldGrowArray(&wp->w_folds, &curwin->w_folds);
    } else if (wip != NULL && wip->wi_optset) {
      copy_winopt(&wip->wi_opt, &curwin->w_onebuf_opt);
      curwin->w_fold_manual = wip->wi_fold_manual;
      curwin->w_foldinvalid = true;
      cloneFoldGrowArray(&wip->wi_folds, &curwin->w_folds);
    } else
      copy_winopt(&curwin->w_allbuf_opt, &curwin->w_onebuf_opt);
  
    /* Set 'foldlevel' to 'foldlevelstart' if it's not negative. */
    if (p_fdls >= 0)
      curwin->w_p_fdl = p_fdls;
    didset_window_options(curwin);
  }
  
  /*
   * Find the position (lnum and col) for the buffer 'buf' for the current
   * window.
   * Returns a pointer to no_position if no position is found.
   */
  pos_T *buflist_findfpos(buf_T *buf)
  {
    static pos_T no_position = INIT_POS_T(1, 0, 0);
  
    wininfo_T *wip = find_wininfo(buf, FALSE);
    return (wip == NULL) ? &no_position : &(wip->wi_fpos);
  }
  
  /*
   * Find the lnum for the buffer 'buf' for the current window.
   */
  linenr_T buflist_findlnum(buf_T *buf)
  {
    return buflist_findfpos(buf)->lnum;
  }
  
  // List all known file names (for :files and :buffers command).
  void buflist_list(exarg_T *eap)
  {
    buf_T       *buf;
    int len;
    int i;
  
    for (buf = firstbuf; buf != NULL && !got_int; buf = buf->b_next) {
      // skip unspecified buffers
      if ((!buf->b_p_bl && !eap->forceit && !strchr((char *)eap->arg, 'u'))
          || (strchr((char *)eap->arg, 'u') && buf->b_p_bl)
          || (strchr((char *)eap->arg, '+')
              && ((buf->b_flags & BF_READERR) || !bufIsChanged(buf)))
          || (strchr((char *)eap->arg, 'a')
              && (buf->b_ml.ml_mfp == NULL || buf->b_nwindows == 0))
          || (strchr((char *)eap->arg, 'h')
              && (buf->b_ml.ml_mfp == NULL || buf->b_nwindows != 0))
          || (strchr((char *)eap->arg, '-') && buf->b_p_ma)
          || (strchr((char *)eap->arg, '=') && !buf->b_p_ro)
          || (strchr((char *)eap->arg, 'x') && !(buf->b_flags & BF_READERR))
          || (strchr((char *)eap->arg, '%') && buf != curbuf)
          || (strchr((char *)eap->arg, '#')
              && (buf == curbuf || curwin->w_alt_fnum != buf->b_fnum))) {
        continue;
      }
      if (buf_spname(buf) != NULL) {
        STRLCPY(NameBuff, buf_spname(buf), MAXPATHL);
      } else {
        home_replace(buf, buf->b_fname, NameBuff, MAXPATHL, true);
      }
  
      if (message_filtered(NameBuff)) {
        continue;
      }
  
      msg_putchar('\n');
      len = vim_snprintf((char *)IObuff, IOSIZE - 20, "%3d%c%c%c%c%c \"%s\"",
          buf->b_fnum,
          buf->b_p_bl ? ' ' : 'u',
          buf == curbuf ? '%' : (curwin->w_alt_fnum == buf->b_fnum ? '#' : ' '),
          buf->b_ml.ml_mfp == NULL ? ' ' : (buf->b_nwindows == 0 ? 'h' : 'a'),
          !MODIFIABLE(buf) ? '-' : (buf->b_p_ro ? '=' : ' '),
          (buf->b_flags & BF_READERR) ? 'x' : (bufIsChanged(buf) ? '+' : ' '),
          NameBuff);
  
      if (len > IOSIZE - 20) {
          len = IOSIZE - 20;
      }
  
      /* put "line 999" in column 40 or after the file name */
      i = 40 - vim_strsize(IObuff);
      do {
        IObuff[len++] = ' ';
      } while (--i > 0 && len < IOSIZE - 18);
      vim_snprintf((char *)IObuff + len, (size_t)(IOSIZE - len),
          _("line %" PRId64),
          buf == curbuf ? (int64_t)curwin->w_cursor.lnum
                        : (int64_t)buflist_findlnum(buf));
      msg_outtrans(IObuff);
      ui_flush();            /* output one line at a time */
      os_breakcheck();
    }
  }
  
  /*
   * Get file name and line number for file 'fnum'.
   * Used by DoOneCmd() for translating '%' and '#'.
   * Used by insert_reg() and cmdline_paste() for '#' register.
   * Return FAIL if not found, OK for success.
   */
  int buflist_name_nr(int fnum, char_u **fname, linenr_T *lnum)
  {
    buf_T       *buf;
  
    buf = buflist_findnr(fnum);
    if (buf == NULL || buf->b_fname == NULL)
      return FAIL;
  
    *fname = buf->b_fname;
    *lnum = buflist_findlnum(buf);
  
    return OK;
  }
  
  /*
   * Set the file name for "buf"' to 'ffname', short file name to 'sfname'.
   * The file name with the full path is also remembered, for when :cd is used.
   * Returns FAIL for failure (file name already in use by other buffer)
   *	OK otherwise.
   */
  int 
  setfname (
      buf_T *buf,
      char_u *ffname,
      char_u *sfname,
      int message                    /* give message when buffer already exists */
  )
  {
    buf_T       *obuf = NULL;
    FileID file_id;
    bool file_id_valid = false;
  
    if (ffname == NULL || *ffname == NUL) {
      /* Removing the name. */
      xfree(buf->b_ffname);
      xfree(buf->b_sfname);
      buf->b_ffname = NULL;
      buf->b_sfname = NULL;
    } else {
      fname_expand(buf, &ffname, &sfname);     /* will allocate ffname */
      if (ffname == NULL)                     /* out of memory */
        return FAIL;
  
      /*
       * if the file name is already used in another buffer:
       * - if the buffer is loaded, fail
       * - if the buffer is not loaded, delete it from the list
       */
      file_id_valid = os_fileid((char *)ffname, &file_id);
      if (!(buf->b_flags & BF_DUMMY)) {
        obuf = buflist_findname_file_id(ffname, &file_id, file_id_valid);
      }
      if (obuf != NULL && obuf != buf) {
        if (obuf->b_ml.ml_mfp != NULL) {          /* it's loaded, fail */
          if (message)
            EMSG(_("E95: Buffer with this name already exists"));
          xfree(ffname);
          return FAIL;
        }
        /* delete from the list */
        close_buffer(NULL, obuf, DOBUF_WIPE, FALSE);
      }
      sfname = vim_strsave(sfname);
  #ifdef USE_FNAME_CASE
      path_fix_case(sfname);            /* set correct case for short file name */
  #endif
      xfree(buf->b_ffname);
      xfree(buf->b_sfname);
      buf->b_ffname = ffname;
      buf->b_sfname = sfname;
    }
    buf->b_fname = buf->b_sfname;
    if (!file_id_valid) {
      buf->file_id_valid = false;
    } else {
      buf->file_id_valid = true;
      buf->file_id = file_id;
    }
  
    buf_name_changed(buf);
    return OK;
  }
  
  /*
   * Crude way of changing the name of a buffer.  Use with care!
   * The name should be relative to the current directory.
   */
  void buf_set_name(int fnum, char_u *name)
  {
    buf_T       *buf;
  
    buf = buflist_findnr(fnum);
    if (buf != NULL) {
      xfree(buf->b_sfname);
      xfree(buf->b_ffname);
      buf->b_ffname = vim_strsave(name);
      buf->b_sfname = NULL;
      /* Allocate ffname and expand into full path.  Also resolves .lnk
       * files on Win32. */
      fname_expand(buf, &buf->b_ffname, &buf->b_sfname);
      buf->b_fname = buf->b_sfname;
    }
  }
  
  /*
   * Take care of what needs to be done when the name of buffer "buf" has
   * changed.
   */
  void buf_name_changed(buf_T *buf)
  {
    /*
     * If the file name changed, also change the name of the swapfile
     */
    if (buf->b_ml.ml_mfp != NULL)
      ml_setname(buf);
  
    if (curwin->w_buffer == buf)
      check_arg_idx(curwin);      /* check file name for arg list */
    maketitle();                  /* set window title */
    status_redraw_all();          /* status lines need to be redrawn */
    fmarks_check_names(buf);      /* check named file marks */
    ml_timestamp(buf);            /* reset timestamp */
  }
  
  /*
   * set alternate file name for current window
   *
   * Used by do_one_cmd(), do_write() and do_ecmd().
   * Return the buffer.
   */
  buf_T *setaltfname(char_u *ffname, char_u *sfname, linenr_T lnum)
  {
    buf_T       *buf;
  
    // Create a buffer.  'buflisted' is not set if it's a new buffer
    buf = buflist_new(ffname, sfname, lnum, 0);
    if (buf != NULL && !cmdmod.keepalt) {
      curwin->w_alt_fnum = buf->b_fnum;
    }
    return buf;
  }
  
  /*
   * Get alternate file name for current window.
   * Return NULL if there isn't any, and give error message if requested.
   */
  char_u * getaltfname(
      bool errmsg                   // give error message
  )
  {
    char_u      *fname;
    linenr_T dummy;
  
    if (buflist_name_nr(0, &fname, &dummy) == FAIL) {
      if (errmsg)
        EMSG(_(e_noalt));
      return NULL;
    }
    return fname;
  }
  
  /*
   * Add a file name to the buflist and return its number.
   * Uses same flags as buflist_new(), except BLN_DUMMY.
   *
   * used by qf_init(), main() and doarglist()
   */
  int buflist_add(char_u *fname, int flags)
  {
    buf_T       *buf;
  
    buf = buflist_new(fname, NULL, (linenr_T)0, flags);
    if (buf != NULL) {
      return buf->b_fnum;
    }
    return 0;
  }
  
  #if defined(BACKSLASH_IN_FILENAME)
  /*
   * Adjust slashes in file names.  Called after 'shellslash' was set.
   */
  void buflist_slash_adjust(void)
  {
    FOR_ALL_BUFFERS(bp) {
      if (bp->b_ffname != NULL)
        slash_adjust(bp->b_ffname);
      if (bp->b_sfname != NULL)
        slash_adjust(bp->b_sfname);
    }
  }
  
  #endif
  
  /*
   * Set alternate cursor position for the current buffer and window "win".
   * Also save the local window option values.
   */
  void buflist_altfpos(win_T *win)
  {
    buflist_setfpos(curbuf, win, win->w_cursor.lnum, win->w_cursor.col, TRUE);
  }
  
  /// Check that "ffname" is not the same file as current file.
  /// Fname must have a full path (expanded by path_to_absolute()).
  ///
  /// @param  ffname  full path name to check
  bool otherfile(char_u *ffname)
    FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_NONNULL_ALL
  {
    return otherfile_buf(curbuf, ffname, NULL, false);
  }
  
  /// Check that "ffname" is not the same file as the file loaded in "buf".
  /// Fname must have a full path (expanded by path_to_absolute()).
  ///
  /// @param  buf            buffer to check
  /// @param  ffname         full path name to check
  /// @param  file_id_p      information about the file at "ffname".
  /// @param  file_id_valid  whether a valid "file_id_p" was passed in.
  static bool otherfile_buf(buf_T *buf, char_u *ffname, FileID *file_id_p,
                            bool file_id_valid)
    FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
  {
    // no name is different
    if (ffname == NULL || *ffname == NUL || buf->b_ffname == NULL) {
      return true;
    }
    if (fnamecmp(ffname, buf->b_ffname) == 0) {
      return false;
    }
    {
      FileID file_id;
      // If no struct stat given, get it now
      if (file_id_p == NULL) {
        file_id_p = &file_id;
        file_id_valid = os_fileid((char *)ffname, file_id_p);
      }
      if (!file_id_valid) {
        // file_id not valid, assume files are different.
        return true;
      }
      // Use dev/ino to check if the files are the same, even when the names
      // are different (possible with links).  Still need to compare the
      // name above, for when the file doesn't exist yet.
      // Problem: The dev/ino changes when a file is deleted (and created
      // again) and remains the same when renamed/moved.  We don't want to
      // stat() each buffer each time, that would be too slow.  Get the
      // dev/ino again when they appear to match, but not when they appear
      // to be different: Could skip a buffer when it's actually the same
      // file.
      if (buf_same_file_id(buf, file_id_p)) {
        buf_set_file_id(buf);
        if (buf_same_file_id(buf, file_id_p)) {
          return false;
        }
      }
    }
    return true;
  }
  
  // Set file_id for a buffer.
  // Must always be called when b_fname is changed!
  void buf_set_file_id(buf_T *buf)
  {
    FileID file_id;
    if (buf->b_fname != NULL
        && os_fileid((char *)buf->b_fname, &file_id)) {
      buf->file_id_valid = true;
      buf->file_id = file_id;
    } else {
      buf->file_id_valid = false;
    }
  }
  
  /// Check that file_id in buffer "buf" matches with "file_id".
  ///
  /// @param  buf      buffer
  /// @param  file_id  file id
  static bool buf_same_file_id(buf_T *buf, FileID *file_id)
    FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_NONNULL_ALL
  {
    return buf->file_id_valid && os_fileid_equal(&(buf->file_id), file_id);
  }
  
  /*
   * Print info about the current buffer.
   */
  void 
  fileinfo (
      int fullname,               /* when non-zero print full path */
      int shorthelp,
      int dont_truncate
  )
  {
    char_u      *name;
    int n;
    char_u      *p;
    char_u      *buffer;
    size_t len;
  
    buffer = xmalloc(IOSIZE);
  
    if (fullname > 1) {       /* 2 CTRL-G: include buffer number */
      vim_snprintf((char *)buffer, IOSIZE, "buf %d: ", curbuf->b_fnum);
      p = buffer + STRLEN(buffer);
    } else
      p = buffer;
  
    *p++ = '"';
    if (buf_spname(curbuf) != NULL)
      STRLCPY(p, buf_spname(curbuf), IOSIZE - (p - buffer));
    else {
      if (!fullname && curbuf->b_fname != NULL)
        name = curbuf->b_fname;
      else
        name = curbuf->b_ffname;
      home_replace(shorthelp ? curbuf : NULL, name, p,
                   (size_t)(IOSIZE - (p - buffer)), true);
    }
  
    vim_snprintf_add((char *)buffer, IOSIZE, "\"%s%s%s%s%s%s",
        curbufIsChanged() ? (shortmess(SHM_MOD)
                             ?  " [+]" : _(" [Modified]")) : " ",
        (curbuf->b_flags & BF_NOTEDITED)
        && !bt_dontwrite(curbuf)
        ? _("[Not edited]") : "",
        (curbuf->b_flags & BF_NEW)
        && !bt_dontwrite(curbuf)
        ? _("[New file]") : "",
        (curbuf->b_flags & BF_READERR) ? _("[Read errors]") : "",
        curbuf->b_p_ro ? (shortmess(SHM_RO) ? _("[RO]")
                          : _("[readonly]")) : "",
        (curbufIsChanged() || (curbuf->b_flags & BF_WRITE_MASK)
         || curbuf->b_p_ro) ?
        " " : "");
    /* With 32 bit longs and more than 21,474,836 lines multiplying by 100
     * causes an overflow, thus for large numbers divide instead. */
    if (curwin->w_cursor.lnum > 1000000L)
      n = (int)(((long)curwin->w_cursor.lnum) /
                ((long)curbuf->b_ml.ml_line_count / 100L));
    else
      n = (int)(((long)curwin->w_cursor.lnum * 100L) /
                (long)curbuf->b_ml.ml_line_count);
    if (curbuf->b_ml.ml_flags & ML_EMPTY) {
      vim_snprintf_add((char *)buffer, IOSIZE, "%s", _(no_lines_msg));
    } else if (p_ru) {
      /* Current line and column are already on the screen -- webb */
      if (curbuf->b_ml.ml_line_count == 1)
        vim_snprintf_add((char *)buffer, IOSIZE, _("1 line --%d%%--"), n);
      else
        vim_snprintf_add((char *)buffer, IOSIZE, _("%" PRId64 " lines --%d%%--"),
            (int64_t)curbuf->b_ml.ml_line_count, n);
    } else {
      vim_snprintf_add((char *)buffer, IOSIZE,
          _("line %" PRId64 " of %" PRId64 " --%d%%-- col "),
          (int64_t)curwin->w_cursor.lnum,
          (int64_t)curbuf->b_ml.ml_line_count,
          n);
      validate_virtcol();
      len = STRLEN(buffer);
      col_print(buffer + len, IOSIZE - len,
          (int)curwin->w_cursor.col + 1, (int)curwin->w_virtcol + 1);
    }
  
    (void)append_arg_number(curwin, buffer, IOSIZE, !shortmess(SHM_FILE));
  
    if (dont_truncate) {
      /* Temporarily set msg_scroll to avoid the message being truncated.
       * First call msg_start() to get the message in the right place. */
      msg_start();
      n = msg_scroll;
      msg_scroll = TRUE;
      msg(buffer);
      msg_scroll = n;
    } else {
      p = msg_trunc_attr(buffer, FALSE, 0);
      if (restart_edit != 0 || (msg_scrolled && !need_wait_return))
        /* Need to repeat the message after redrawing when:
         * - When restart_edit is set (otherwise there will be a delay
         *   before redrawing).
         * - When the screen was scrolled but there is no wait-return
         *   prompt. */
        set_keep_msg(p, 0);
    }
  
    xfree(buffer);
  }
  
  void col_print(char_u *buf, size_t buflen, int col, int vcol)
  {
    if (col == vcol)
      vim_snprintf((char *)buf, buflen, "%d", col);
    else
      vim_snprintf((char *)buf, buflen, "%d-%d", col, vcol);
  }
  
  /*
   * put file name in title bar of window and in icon title
   */
  
  static char_u *lasttitle = NULL;
  static char_u *lasticon = NULL;
  
  void maketitle(void)
  {
    char_u      *t_str = NULL;
    char_u      *i_name;
    char_u      *i_str = NULL;
    int maxlen = 0;
    int len;
    int mustset;
    char buf[IOSIZE];
  
    if (!redrawing()) {
      /* Postpone updating the title when 'lazyredraw' is set. */
      need_maketitle = TRUE;
      return;
    }
  
    need_maketitle = FALSE;
    if (!p_title && !p_icon && lasttitle == NULL && lasticon == NULL)
      return;
  
    if (p_title) {
      if (p_titlelen > 0) {
        maxlen = (int)(p_titlelen * Columns / 100);
        if (maxlen < 10) {
          maxlen = 10;
        }
      }
  
      if (*p_titlestring != NUL) {
        if (stl_syntax & STL_IN_TITLE) {
          int use_sandbox = FALSE;
          int save_called_emsg = called_emsg;
  
          use_sandbox = was_set_insecurely((char_u *)"titlestring", 0);
          called_emsg = false;
          build_stl_str_hl(curwin, (char_u *)buf, sizeof(buf),
                           p_titlestring, use_sandbox,
                           0, maxlen, NULL, NULL);
          t_str = (char_u *)buf;
          if (called_emsg) {
            set_string_option_direct((char_u *)"titlestring", -1, (char_u *)"",
                                     OPT_FREE, SID_ERROR);
          }
          called_emsg |= save_called_emsg;
        } else {
          t_str = p_titlestring;
        }
      } else {
        // Format: "fname + (path) (1 of 2) - VIM".
  
  #define SPACE_FOR_FNAME (sizeof(buf) - 100)
  #define SPACE_FOR_DIR   (sizeof(buf) - 20)
  #define SPACE_FOR_ARGNR (sizeof(buf) - 10)  // At least room for " - NVIM".
        char *buf_p = buf;
        if (curbuf->b_fname == NULL) {
          const size_t size = xstrlcpy(buf_p, _("[No Name]"),
                                       SPACE_FOR_FNAME + 1);
          buf_p += MIN(size, SPACE_FOR_FNAME);
        } else {
          buf_p += transstr_buf((const char *)path_tail(curbuf->b_fname),
                                buf_p, SPACE_FOR_FNAME + 1);
        }
  
        switch (bufIsChanged(curbuf)
                | (curbuf->b_p_ro << 1)
                | (!MODIFIABLE(curbuf) << 2)) {
          case 0: break;
          case 1: buf_p = strappend(buf_p, " +"); break;
          case 2: buf_p = strappend(buf_p, " ="); break;
          case 3: buf_p = strappend(buf_p, " =+"); break;
          case 4:
          case 6: buf_p = strappend(buf_p, " -"); break;
          case 5:
          case 7: buf_p = strappend(buf_p, " -+"); break;
          default: assert(false);
        }
  
        if (curbuf->b_fname != NULL) {
          // Get path of file, replace home dir with ~.
          *buf_p++ = ' ';
          *buf_p++ = '(';
          home_replace(curbuf, curbuf->b_ffname, (char_u *)buf_p,
                       (SPACE_FOR_DIR - (size_t)(buf_p - buf)), true);
  #ifdef BACKSLASH_IN_FILENAME
          // Avoid "c:/name" to be reduced to "c".
          if (isalpha((uint8_t)buf_p) && *(buf_p + 1) == ':') {
            buf_p += 2;
          }
  #endif
          // Remove the file name.
          char *p = (char *)path_tail_with_sep((char_u *)buf_p);
          if (p == buf_p) {
            // Must be a help buffer.
            xstrlcpy(buf_p, _("help"), SPACE_FOR_DIR - (size_t)(buf_p - buf));
          } else {
            *p = NUL;
          }
  
          // Translate unprintable chars and concatenate.  Keep some
          // room for the server name.  When there is no room (very long
          // file name) use (...).
          if ((size_t)(buf_p - buf) < SPACE_FOR_DIR) {
            char *const tbuf = transstr(buf_p);
            const size_t free_space = SPACE_FOR_DIR - (size_t)(buf_p - buf) + 1;
            const size_t dir_len = xstrlcpy(buf_p, tbuf, free_space);
            buf_p += MIN(dir_len, free_space - 1);
            xfree(tbuf);
          } else {
            const size_t free_space = SPACE_FOR_ARGNR - (size_t)(buf_p - buf) + 1;
            const size_t dots_len = xstrlcpy(buf_p, "...", free_space);
            buf_p += MIN(dots_len, free_space - 1);
          }
          *buf_p++ = ')';
          *buf_p = NUL;
        } else {
          *buf_p = NUL;
        }
  
        append_arg_number(curwin, (char_u *)buf_p,
                          (int)(SPACE_FOR_ARGNR - (size_t)(buf_p - buf)), false);
  
        xstrlcat(buf_p, " - NVIM", (sizeof(buf) - (size_t)(buf_p - buf)));
  
        if (maxlen > 0) {
          // Make it shorter by removing a bit in the middle.
          if (vim_strsize((char_u *)buf) > maxlen) {
            trunc_string((char_u *)buf, (char_u *)buf, maxlen, sizeof(buf));
          }
        }
        t_str = (char_u *)buf;
  #undef SPACE_FOR_FNAME
  #undef SPACE_FOR_DIR
  #undef SPACE_FOR_ARGNR
      }
    }
    mustset = ti_change(t_str, &lasttitle);
  
    if (p_icon) {
      i_str = (char_u *)buf;
      if (*p_iconstring != NUL) {
        if (stl_syntax & STL_IN_ICON) {
          int use_sandbox = FALSE;
          int save_called_emsg = called_emsg;
  
          use_sandbox = was_set_insecurely((char_u *)"iconstring", 0);
          called_emsg = FALSE;
          build_stl_str_hl(curwin, i_str, sizeof(buf),
              p_iconstring, use_sandbox,
              0, 0, NULL, NULL);
          if (called_emsg)
            set_string_option_direct((char_u *)"iconstring", -1,
                (char_u *)"", OPT_FREE, SID_ERROR);
          called_emsg |= save_called_emsg;
        } else
          i_str = p_iconstring;
      } else {
        if (buf_spname(curbuf) != NULL)
          i_name = buf_spname(curbuf);
        else                          /* use file name only in icon */
          i_name = path_tail(curbuf->b_ffname);
        *i_str = NUL;
        /* Truncate name at 100 bytes. */
        len = (int)STRLEN(i_name);
        if (len > 100) {
          len -= 100;
          if (has_mbyte)
            len += (*mb_tail_off)(i_name, i_name + len) + 1;
          i_name += len;
        }
        STRCPY(i_str, i_name);
        trans_characters(i_str, IOSIZE);
      }
    }
  
    mustset |= ti_change(i_str, &lasticon);
  
    if (mustset)
      resettitle();
  }
  
  /// Used for title and icon: Check if "str" differs from "*last".  Set "*last"
  /// from "str" if it does by freeing the old value of "*last" and duplicating
  /// "str".
  ///
  /// @param          str   desired title string
  /// @param[in,out]  last  current title string
  //
  /// @return true when "*last" changed.
  static bool ti_change(char_u *str, char_u **last)
    FUNC_ATTR_WARN_UNUSED_RESULT
  {
    if ((str == NULL) != (*last == NULL)
        || (str != NULL && *last != NULL && STRCMP(str, *last) != 0)) {
      xfree(*last);
      if (str == NULL) {
        *last = NULL;
      } else {
        *last = vim_strsave(str);
      }
      return true;
    }
    return false;
  }
  
  
  /// Set current window title
  void resettitle(void)
  {
    ui_call_set_icon(cstr_as_string((char *)lasticon));
    ui_call_set_title(cstr_as_string((char *)lasttitle));
    ui_flush();
  }
  
  # if defined(EXITFREE)
  void free_titles(void)
  {
    xfree(lasttitle);
    xfree(lasticon);
  }
  
  # endif
  
  /// Enumeration specifying the valid numeric bases that can
  /// be used when printing numbers in the status line.
  typedef enum {
    kNumBaseDecimal = 10,
    kNumBaseHexadecimal = 16
  } NumberBase;
  
  
  /// Build a string from the status line items in "fmt".
  /// Return length of string in screen cells.
  ///
  /// Normally works for window "wp", except when working for 'tabline' then it
  /// is "curwin".
  ///
  /// Items are drawn interspersed with the text that surrounds it
  /// Specials: %-<wid>(xxx%) => group, %= => separation marker, %< => truncation
  /// Item: %-<minwid>.<maxwid><itemch> All but <itemch> are optional
  ///
  /// If maxwidth is not zero, the string will be filled at any middle marker
  /// or truncated if too long, fillchar is used for all whitespace.
  ///
  /// @param wp The window to build a statusline for
  /// @param out The output buffer to write the statusline to
  ///            Note: This should not be NameBuff
  /// @param outlen The length of the output buffer
  /// @param fmt The statusline format string
  /// @param use_sandbox Use a sandboxed environment when evaluating fmt
  /// @param fillchar Character to use when filling empty space in the statusline
  /// @param maxwidth The maximum width to make the statusline
  /// @param hltab HL attributes (can be NULL)
  /// @param tabtab Tab clicks definition (can be NULL).
  ///
  /// @return The final width of the statusline
  int build_stl_str_hl(
      win_T *wp,
      char_u *out,
      size_t outlen,
      char_u *fmt,
      int use_sandbox,
      char_u fillchar,
      int maxwidth,
      struct stl_hlrec *hltab,
      StlClickRecord *tabtab
  )
  {
    int groupitems[STL_MAX_ITEM];
    struct stl_item {
      // Where the item starts in the status line output buffer
      char_u *start;
      // Function to run for ClickFunc items.
      char *cmd;
      // The minimum width of the item
      int minwid;
      // The maximum width of the item
      int maxwid;
      enum {
        Normal,
        Empty,
        Group,
        Separate,
        Highlight,
        TabPage,
        ClickFunc,
        Trunc
      } type;
    } items[STL_MAX_ITEM];
  #define TMPLEN 70
    char_u tmp[TMPLEN];
    char_u      *usefmt = fmt;
  
    // When the format starts with "%!" then evaluate it as an expression and
    // use the result as the actual format string.
    if (fmt[0] == '%' && fmt[1] == '!') {
      usefmt = eval_to_string_safe(fmt + 2, NULL, use_sandbox);
      if (usefmt == NULL)
        usefmt = fmt;
    }
  
    if (fillchar == 0)
      fillchar = ' ';
    // Can't handle a multi-byte fill character yet.
    else if (mb_char2len(fillchar) > 1)
      fillchar = '-';
  
    // Get line & check if empty (cursorpos will show "0-1").
    char_u *line_ptr = ml_get_buf(wp->w_buffer, wp->w_cursor.lnum, false);
    bool empty_line = (*line_ptr == NUL);
  
    // Get the byte value now, in case we need it below. This is more
    // efficient than making a copy of the line.
    int byteval;
    if (wp->w_cursor.col > (colnr_T)STRLEN(line_ptr)) {
      byteval = 0;
    } else {
      byteval = utf_ptr2char(line_ptr + wp->w_cursor.col);
    }
  
    int groupdepth = 0;
  
    int curitem = 0;
    bool prevchar_isflag = true;
    bool prevchar_isitem = false;
  
    // out_p is the current position in the output buffer
    char_u *out_p = out;
  
    // out_end_p is the last valid character in the output buffer
    // Note: The null termination character must occur here or earlier,
    //       so any user-visible characters must occur before here.
    char_u *out_end_p = (out + outlen) - 1;
  
  
    // Proceed character by character through the statusline format string
    // fmt_p is the current positon in the input buffer
    for (char_u *fmt_p = usefmt; *fmt_p; ) {
      if (curitem == STL_MAX_ITEM) {
        // There are too many items.  Add the error code to the statusline
        // to give the user a hint about what went wrong.
        if (out_p + 5 < out_end_p) {
          memmove(out_p, " E541", (size_t)5);
          out_p += 5;
        }
        break;
      }
  
      if (*fmt_p != NUL && *fmt_p != '%') {
        prevchar_isflag = prevchar_isitem = false;
      }
  
      // Copy the formatting verbatim until we reach the end of the string
      // or find a formatting item (denoted by `%`)
      // or run out of room in our output buffer.
      while (*fmt_p != NUL && *fmt_p != '%' && out_p < out_end_p)
        *out_p++ = *fmt_p++;
  
      // If we have processed the entire format string or run out of
      // room in our output buffer, exit the loop.
      if (*fmt_p == NUL || out_p >= out_end_p)
        break;
  
      // The rest of this loop will handle a single `%` item.
      // Note: We increment here to skip over the `%` character we are currently
      //       on so we can process the item's contents.
      fmt_p++;
  
      // Ignore `%` at the end of the format string
      if (*fmt_p == NUL) {
        break;
      }
  
      // Two `%` in a row is the escape sequence to print a
      // single `%` in the output buffer.
      if (*fmt_p == '%') {
        *out_p++ = *fmt_p++;
        prevchar_isflag = prevchar_isitem = false;
        continue;
      }
  
      // STL_SEPARATE: Separation place between left and right aligned items.
      if (*fmt_p == STL_SEPARATE) {
        fmt_p++;
        // Ignored when we are inside of a grouping
        if (groupdepth > 0) {
          continue;
        }
        items[curitem].type = Separate;
        items[curitem++].start = out_p;
        continue;
      }
  
      // STL_TRUNCMARK: Where to begin truncating if the statusline is too long.
      if (*fmt_p == STL_TRUNCMARK) {
        fmt_p++;
        items[curitem].type = Trunc;
        items[curitem++].start = out_p;
        continue;
      }
  
      // The end of a grouping
      if (*fmt_p == ')') {
        fmt_p++;
        // Ignore if we are not actually inside a group currently
        if (groupdepth < 1) {
          continue;
        }
        groupdepth--;
  
        // Determine how long the group is.
        // Note: We set the current output position to null
        //       so `vim_strsize` will work.
        char_u *t = items[groupitems[groupdepth]].start;
        *out_p = NUL;
        long group_len = vim_strsize(t);
  
        // If the group contained internal items
        // and the group did not have a minimum width,
        // and if there were no normal items in the group,
        // move the output pointer back to where the group started.
        // Note: This erases any non-item characters that were in the group.
        //       Otherwise there would be no reason to do this step.
        if (curitem > groupitems[groupdepth] + 1
            && items[groupitems[groupdepth]].minwid == 0) {
          bool has_normal_items = false;
          for (long n = groupitems[groupdepth] + 1; n < curitem; n++) {
            if (items[n].type == Normal || items[n].type == Highlight) {
              has_normal_items = true;
              break;
            }
          }
  
          if (!has_normal_items) {
            out_p = t;
            group_len = 0;
          }
        }
  
        // If the group is longer than it is allowed to be
        // truncate by removing bytes from the start of the group text.
        if (group_len > items[groupitems[groupdepth]].maxwid) {
          // { Determine the number of bytes to remove
          long n;
          if (has_mbyte) {
            /* Find the first character that should be included. */
            n = 0;
            while (group_len >= items[groupitems[groupdepth]].maxwid) {
              group_len -= ptr2cells(t + n);
              n += (*mb_ptr2len)(t + n);
            }
          } else {
            n = (long)(out_p - t) - items[groupitems[groupdepth]].maxwid + 1;
          }
          // }
  
          // Prepend the `<` to indicate that the output was truncated.
          *t = '<';
  
          // { Move the truncated output
          memmove(t + 1, t + n, (size_t)(out_p - (t + n)));
          out_p = out_p - n + 1;
          // Fill up space left over by half a double-wide char.
          while (++group_len < items[groupitems[groupdepth]].minwid) {
            *out_p++ = fillchar;
          }
          // }
  
          // correct the start of the items for the truncation
          for (int idx = groupitems[groupdepth] + 1; idx < curitem; idx++) {
            // Shift everything back by the number of removed bytes
            items[idx].start -= n;
  
            // If the item was partially or completely truncated, set its
            // start to the start of the group
            if (items[idx].start < t) {
              items[idx].start = t;
            }
          }
        // If the group is shorter than the minimum width, add padding characters.
        } else if (abs(items[groupitems[groupdepth]].minwid) > group_len) {
          long min_group_width = items[groupitems[groupdepth]].minwid;
          // If the group is left-aligned, add characters to the right.
          if (min_group_width < 0) {
            min_group_width = 0 - min_group_width;
            while (group_len++ < min_group_width && out_p < out_end_p)
              *out_p++ = fillchar;
          // If the group is right-aligned, shift everything to the right and
          // prepend with filler characters.
          } else {
            // { Move the group to the right
            memmove(t + min_group_width - group_len, t, (size_t)(out_p - t));
            group_len = min_group_width - group_len;
            if (out_p + group_len >= (out_end_p + 1)) {
              group_len = (long)(out_end_p - out_p);
            }
            out_p += group_len;
            // }
  
            // Adjust item start positions
            for (int n = groupitems[groupdepth] + 1; n < curitem; n++) {
              items[n].start += group_len;
            }
  
            // Prepend the fill characters
            for (; group_len > 0; group_len--) {
              *t++ = fillchar;
            }
          }
        }
        continue;
      }
      int minwid = 0;
      int maxwid = 9999;
      bool left_align = false;
  
      // Denotes that numbers should be left-padded with zeros
      bool zeropad = (*fmt_p == '0');
      if (zeropad) {
        fmt_p++;
      }
  
      // Denotes that the item should be left-aligned.
      // This is tracked by using a negative length.
      if (*fmt_p == '-') {
        fmt_p++;
        left_align = true;
      }
  
      // The first digit group is the item's min width
      if (ascii_isdigit(*fmt_p)) {
        minwid = getdigits_int(&fmt_p);
        if (minwid < 0)           /* overflow */
          minwid = 0;
      }
  
      // User highlight groups override the min width field
      // to denote the styling to use.
      if (*fmt_p == STL_USER_HL) {
        items[curitem].type = Highlight;
        items[curitem].start = out_p;
        items[curitem].minwid = minwid > 9 ? 1 : minwid;
        fmt_p++;
        curitem++;
        continue;
      }
  
      // TABPAGE pairs are used to denote a region that when clicked will
      // either switch to or close a tab.
      //
      // Ex: tabline=%0Ttab\ zero%X
      //   This tabline has a TABPAGENR item with minwid `0`,
      //   which is then closed with a TABCLOSENR item.
      //   Clicking on this region with mouse enabled will switch to tab 0.
      //   Setting the minwid to a different value will switch
      //   to that tab, if it exists
      //
      // Ex: tabline=%1Xtab\ one%X
      //   This tabline has a TABCLOSENR item with minwid `1`,
      //   which is then closed with a TABCLOSENR item.
      //   Clicking on this region with mouse enabled will close tab 0.
      //   This is determined by the following formula:
      //      tab to close = (1 - minwid)
      //   This is because for TABPAGENR we use `minwid` = `tab number`.
      //   For TABCLOSENR we store the tab number as a negative value.
      //   Because 0 is a valid TABPAGENR value, we have to
      //   start our numbering at `-1`.
      //   So, `-1` corresponds to us wanting to close tab `0`
      //
      // Note: These options are only valid when creating a tabline.
      if (*fmt_p == STL_TABPAGENR || *fmt_p == STL_TABCLOSENR) {
        if (*fmt_p == STL_TABCLOSENR) {
          if (minwid == 0) {
            // %X ends the close label, go back to the previous tab label nr.
            for (long n = curitem - 1; n >= 0; n--) {
              if (items[n].type == TabPage && items[n].minwid >= 0) {
                minwid = items[n].minwid;
                break;
              }
            }
          } else {
            // close nrs are stored as negative values
            minwid = -minwid;
          }
        }
        items[curitem].type = TabPage;
        items[curitem].start = out_p;
        items[curitem].minwid = minwid;
        fmt_p++;
        curitem++;
        continue;
      }
  
      if (*fmt_p == STL_CLICK_FUNC) {
        fmt_p++;
        char *t = (char *) fmt_p;
        while (*fmt_p != STL_CLICK_FUNC && *fmt_p) {
          fmt_p++;
        }
        if (*fmt_p != STL_CLICK_FUNC) {
          break;
        }
        items[curitem].type = ClickFunc;
        items[curitem].start = out_p;
        items[curitem].cmd = xmemdupz(t, (size_t)(((char *)fmt_p - t)));
        items[curitem].minwid = minwid;
        fmt_p++;
        curitem++;
        continue;
      }
  
      // Denotes the end of the minwid
      // the maxwid may follow immediately after
      if (*fmt_p == '.') {
        fmt_p++;
        if (ascii_isdigit(*fmt_p)) {
          maxwid = getdigits_int(&fmt_p);
          if (maxwid <= 0)                /* overflow */
            maxwid = 50;
        }
      }
  
      // Bound the minimum width at 50.
      // Make the number negative to denote left alignment of the item
      minwid = (minwid > 50 ? 50 : minwid) * (left_align ? -1 : 1);
  
      // Denotes the start of a new group
      if (*fmt_p == '(') {
        groupitems[groupdepth++] = curitem;
        items[curitem].type = Group;
        items[curitem].start = out_p;
        items[curitem].minwid = minwid;
        items[curitem].maxwid = maxwid;
        fmt_p++;
        curitem++;
        continue;
      }
  
      // An invalid item was specified.
      // Continue processing on the next character of the format string.
      if (vim_strchr(STL_ALL, *fmt_p) == NULL) {
        fmt_p++;
        continue;
      }
  
      // The status line item type
      char_u opt = *fmt_p++;
  
      // OK - now for the real work
      NumberBase base = kNumBaseDecimal;
      bool itemisflag = false;
      bool fillable = true;
      long num = -1;
      char_u *str = NULL;
      switch (opt) {
      case STL_FILEPATH:
      case STL_FULLPATH:
      case STL_FILENAME:
      {
        // Set fillable to false so that ' ' in the filename will not
        // get replaced with the fillchar
        fillable = false;
        if (buf_spname(wp->w_buffer) != NULL) {
          STRLCPY(NameBuff, buf_spname(wp->w_buffer), MAXPATHL);
        } else {
          char_u *t = (opt == STL_FULLPATH) ? wp->w_buffer->b_ffname
                       : wp->w_buffer->b_fname;
          home_replace(wp->w_buffer, t, NameBuff, MAXPATHL, true);
        }
        trans_characters(NameBuff, MAXPATHL);
        if (opt != STL_FILENAME)
          str = NameBuff;
        else
          str = path_tail(NameBuff);
        break;
      }
      case STL_VIM_EXPR:     /* '{' */
      {
        itemisflag = true;
  
        // Attempt to copy the expression to evaluate into
        // the output buffer as a null-terminated string.
        char_u *t = out_p;
        while (*fmt_p != '}' && *fmt_p != NUL && out_p < out_end_p)
          *out_p++ = *fmt_p++;
        if (*fmt_p != '}')            /* missing '}' or out of space */
          break;
        fmt_p++;
        *out_p = 0;
  
        // Move our position in the output buffer
        // to the beginning of the expression
        out_p = t;
  
        // { Evaluate the expression
  
        // Store the current buffer number as a string variable
        vim_snprintf((char *)tmp, sizeof(tmp), "%d", curbuf->b_fnum);
        set_internal_string_var((char_u *)"g:actual_curbuf", tmp);
  
        buf_T *o_curbuf = curbuf;
        win_T *o_curwin = curwin;
        curwin = wp;
        curbuf = wp->w_buffer;
  
        // Note: The result stored in `t` is unused.
        str = eval_to_string_safe(out_p, &t, use_sandbox);
  
        curwin = o_curwin;
        curbuf = o_curbuf;
  
        // Remove the variable we just stored
        do_unlet(S_LEN("g:actual_curbuf"), true);
  
        // }
  
        // Check if the evaluated result is a number.
        // If so, convert the number to an int and free the string.
        if (str != NULL && *str != 0) {
          if (*skipdigits(str) == NUL) {
            num = atoi((char *)str);
            xfree(str);
            str = NULL;
            itemisflag = false;
          }
        }
        break;
      }
  
      case STL_LINE:
        num = (wp->w_buffer->b_ml.ml_flags & ML_EMPTY)
              ? 0L : (long)(wp->w_cursor.lnum);
        break;
  
      case STL_NUMLINES:
        num = wp->w_buffer->b_ml.ml_line_count;
        break;
  
      case STL_COLUMN:
        num = !(State & INSERT) && empty_line
              ? 0 : (int)wp->w_cursor.col + 1;
        break;
  
      case STL_VIRTCOL:
      case STL_VIRTCOL_ALT:
      {
        // In list mode virtcol needs to be recomputed
        colnr_T virtcol = wp->w_virtcol;
        if (wp->w_p_list && lcs_tab1 == NUL) {
          wp->w_p_list = FALSE;
          getvcol(wp, &wp->w_cursor, NULL, &virtcol, NULL);
          wp->w_p_list = TRUE;
        }
        ++virtcol;
        // Don't display %V if it's the same as %c.
        if (opt == STL_VIRTCOL_ALT
            && (virtcol == (colnr_T)(!(State & INSERT) && empty_line
                                     ? 0 : (int)wp->w_cursor.col + 1)))
          break;
        num = (long)virtcol;
        break;
      }
  
      case STL_PERCENTAGE:
        num = (int)(((long)wp->w_cursor.lnum * 100L) /
                    (long)wp->w_buffer->b_ml.ml_line_count);
        break;
  
      case STL_ALTPERCENT:
        // Store the position percentage in our temporary buffer.
        // Note: We cannot store the value in `num` because
        //       `get_rel_pos` can return a named position. Ex: "Top"
        get_rel_pos(wp, tmp, TMPLEN);
        str = tmp;
        break;
  
      case STL_ARGLISTSTAT:
        fillable = false;
  
        // Note: This is important because `append_arg_number` starts appending
        //       at the end of the null-terminated string.
        //       Setting the first byte to null means it will place the argument
        //       number string at the beginning of the buffer.
        tmp[0] = 0;
  
        // Note: The call will only return true if it actually
        //       appended data to the `tmp` buffer.
        if (append_arg_number(wp, tmp, (int)sizeof(tmp), false)) {
          str = tmp;
        }
        break;
  
      case STL_KEYMAP:
        fillable = false;
        if (get_keymap_str(wp, (char_u *)"<%s>", tmp, TMPLEN))
          str = tmp;
        break;
      case STL_PAGENUM:
        num = printer_page_num;
        break;
  
      case STL_BUFNO:
        num = wp->w_buffer->b_fnum;
        break;
  
      case STL_OFFSET_X:
        base = kNumBaseHexadecimal;
        FALLTHROUGH;
      case STL_OFFSET:
      {
        long l = ml_find_line_or_offset(wp->w_buffer, wp->w_cursor.lnum, NULL,
                                        false);
        num = (wp->w_buffer->b_ml.ml_flags & ML_EMPTY) || l < 0 ?
              0L : l + 1 + (!(State & INSERT) && empty_line ?
                            0 : (int)wp->w_cursor.col);
        break;
      }
      case STL_BYTEVAL_X:
        base = kNumBaseHexadecimal;
        FALLTHROUGH;
      case STL_BYTEVAL:
        num = byteval;
        if (num == NL)
          num = 0;
        else if (num == CAR && get_fileformat(wp->w_buffer) == EOL_MAC)
          num = NL;
        break;
  
      case STL_ROFLAG:
      case STL_ROFLAG_ALT:
        itemisflag = true;
        if (wp->w_buffer->b_p_ro)
          str = (char_u *)((opt == STL_ROFLAG_ALT) ? ",RO" : _("[RO]"));
        break;
  
      case STL_HELPFLAG:
      case STL_HELPFLAG_ALT:
        itemisflag = true;
        if (wp->w_buffer->b_help)
          str = (char_u *)((opt == STL_HELPFLAG_ALT) ? ",HLP"
                           : _("[Help]"));
        break;
  
      case STL_FILETYPE:
        // Copy the filetype if it is not null and the formatted string will fit
        // in the temporary buffer
        // (including the brackets and null terminating character)
        if (*wp->w_buffer->b_p_ft != NUL
            && STRLEN(wp->w_buffer->b_p_ft) < TMPLEN - 3) {
          vim_snprintf((char *)tmp, sizeof(tmp), "[%s]",
              wp->w_buffer->b_p_ft);
          str = tmp;
        }
        break;
  
      case STL_FILETYPE_ALT:
      {
        itemisflag = true;
        // Copy the filetype if it is not null and the formatted string will fit
        // in the temporary buffer
        // (including the comma and null terminating character)
        if (*wp->w_buffer->b_p_ft != NUL
            && STRLEN(wp->w_buffer->b_p_ft) < TMPLEN - 2) {
          vim_snprintf((char *)tmp, sizeof(tmp), ",%s",
              wp->w_buffer->b_p_ft);
          // Uppercase the file extension
          for (char_u *t = tmp; *t != 0; t++) {
            *t = (char_u)TOUPPER_LOC(*t);
          }
          str = tmp;
        }
        break;
      }
      case STL_PREVIEWFLAG:
      case STL_PREVIEWFLAG_ALT:
        itemisflag = true;
        if (wp->w_p_pvw)
          str = (char_u *)((opt == STL_PREVIEWFLAG_ALT) ? ",PRV"
                           : _("[Preview]"));
        break;
  
      case STL_QUICKFIX:
        if (bt_quickfix(wp->w_buffer))
          str = (char_u *)(wp->w_llist_ref
                           ? _(msg_loclist)
                           : _(msg_qflist));
        break;
  
      case STL_MODIFIED:
      case STL_MODIFIED_ALT:
        itemisflag = true;
        switch ((opt == STL_MODIFIED_ALT)
                + bufIsChanged(wp->w_buffer) * 2
                + (!MODIFIABLE(wp->w_buffer)) * 4) {
        case 2: str = (char_u *)"[+]"; break;
        case 3: str = (char_u *)",+"; break;
        case 4: str = (char_u *)"[-]"; break;
        case 5: str = (char_u *)",-"; break;
        case 6: str = (char_u *)"[+-]"; break;
        case 7: str = (char_u *)",+-"; break;
        }
        break;
  
      case STL_HIGHLIGHT:
      {
        // { The name of the highlight is surrounded by `#`
        char_u *t = fmt_p;
        while (*fmt_p != '#' && *fmt_p != NUL) {
          ++fmt_p;
        }
        // }
  
        // Create a highlight item based on the name
        if (*fmt_p == '#') {
          items[curitem].type = Highlight;
          items[curitem].start = out_p;
          items[curitem].minwid = -syn_namen2id(t, (int)(fmt_p - t));
          curitem++;
          fmt_p++;
        }
        continue;
      }
      }
  
      // If we made it this far, the item is normal and starts at
      // our current position in the output buffer.
      // Non-normal items would have `continued`.
      items[curitem].start = out_p;
      items[curitem].type = Normal;
  
      // Copy the item string into the output buffer
      if (str != NULL && *str) {
        // { Skip the leading `,` or ` ` if the item is a flag
        //  and the proper conditions are met
        char_u *t = str;
        if (itemisflag) {
          if ((t[0] && t[1])
              && ((!prevchar_isitem && *t == ',')
                  || (prevchar_isflag && *t == ' ')))
            t++;
          prevchar_isflag = true;
        }
        // }
  
        long l = vim_strsize(t);
  
        // If this item is non-empty, record that the last thing
        // we put in the output buffer was an item
        if (l > 0) {
          prevchar_isitem = true;
        }
  
        // If the item is too wide, truncate it from the beginning
        if (l > maxwid) {
          while (l >= maxwid)
            if (has_mbyte) {
              l -= ptr2cells(t);
              t += (*mb_ptr2len)(t);
            } else {
              l -= byte2cells(*t++);
            }
  
          // Early out if there isn't enough room for the truncation marker
          if (out_p >= out_end_p)
            break;
  
          // Add the truncation marker
          *out_p++ = '<';
        }
  
        // If the item is right aligned and not wide enough,
        // pad with fill characters.
        if (minwid > 0) {
          for (; l < minwid && out_p < out_end_p; l++) {
            // Don't put a "-" in front of a digit.
            if (l + 1 == minwid && fillchar == '-' && ascii_isdigit(*t))
              *out_p++ = ' ';
            else
              *out_p++ = fillchar;
          }
          minwid = 0;
        } else {
          // Note: The negative value denotes a left aligned item.
          //       Here we switch the minimum width back to a positive value.
          minwid *= -1;
        }
  
        // { Copy the string text into the output buffer
        while (*t && out_p < out_end_p) {
          *out_p++ = *t++;
          // Change a space by fillchar, unless fillchar is '-' and a
          // digit follows.
          if (fillable && out_p[-1] == ' '
              && (!ascii_isdigit(*t) || fillchar != '-'))
            out_p[-1] = fillchar;
        }
        // }
  
        // For left-aligned items, fill any remaining space with the fillchar
        for (; l < minwid && out_p < out_end_p; l++) {
          *out_p++ = fillchar;
        }
  
      // Otherwise if the item is a number, copy that to the output buffer.
      } else if (num >= 0) {
        if (out_p + 20 > out_end_p)
          break;                  /* not sufficient space */
        prevchar_isitem = true;
  
        // { Build the formatting string
        char_u nstr[20];
        char_u *t = nstr;
        if (opt == STL_VIRTCOL_ALT) {
          *t++ = '-';
          minwid--;
        }
        *t++ = '%';
        if (zeropad) {
          *t++ = '0';
        }
  
        // Note: The `*` means we take the width as one of the arguments
        *t++ = '*';
        *t++ = (char_u)(base == kNumBaseHexadecimal ? 'X' : 'd');
        *t = 0;
        // }
  
        // { Determine how many characters the number will take up when printed
        //  Note: We have to cast the base because the compiler uses
        //        unsigned ints for the enum values.
        long num_chars = 1;
        for (long n = num; n >= (int) base; n /= (int) base) {
          num_chars++;
        }
  
        // VIRTCOL_ALT takes up an extra character because
        // of the `-` we added above.
        if (opt == STL_VIRTCOL_ALT) {
          num_chars++;
        }
        // }
  
        assert(out_end_p >= out_p);
        size_t remaining_buf_len = (size_t)(out_end_p - out_p) + 1;
  
        // If the number is going to take up too much room
        // Figure out the approximate number in "scientific" type notation.
        // Ex: 14532 with maxwid of 4 -> '14>3'
        if (num_chars > maxwid) {
          // Add two to the width because the power piece will take
          // two extra characters
          num_chars += 2;
  
          // How many extra characters there are
          long n = num_chars - maxwid;
  
          // { Reduce the number by base^n
          while (num_chars-- > maxwid) {
            num /= (long)base;
          }
          // }
  
          // { Add the format string for the exponent bit
          *t++ = '>';
          *t++ = '%';
          // Use the same base as the first number
          *t = t[-3];
          *++t = 0;
          // }
  
          vim_snprintf((char *)out_p, remaining_buf_len, (char *)nstr,
              0, num, n);
        } else {
          vim_snprintf((char *)out_p, remaining_buf_len, (char *)nstr,
              minwid, num);
        }
  
        // Advance the output buffer position to the end of the
        // number we just printed
        out_p += STRLEN(out_p);
  
      // Otherwise, there was nothing to print so mark the item as empty
      } else {
        items[curitem].type = Empty;
      }
  
      // Only free the string buffer if we allocated it.
      // Note: This is not needed if `str` is pointing at `tmp`
      if (opt == STL_VIM_EXPR) {
        xfree(str);
      }
  
      if (num >= 0 || (!itemisflag && str && *str))
        prevchar_isflag = false;              /* Item not NULL, but not a flag */
  
      // Item processed, move to the next
      curitem++;
    }
  
    *out_p = NUL;
    int itemcnt = curitem;
  
    // Free the format buffer if we allocated it internally
    if (usefmt != fmt) {
      xfree(usefmt);
    }
  
    // We have now processed the entire statusline format string.
    // What follows is post-processing to handle alignment and highlighting.
  
    int width = vim_strsize(out);
    if (maxwidth > 0 && width > maxwidth) {
      // Result is too long, must truncate somewhere.
      int item_idx = 0;
      char_u *trunc_p;
  
      // If there are no items, truncate from beginning
      if (itemcnt == 0) {
        trunc_p = out;
  
      // Otherwise, look for the truncation item
      } else {
        // Default to truncating at the first item
        trunc_p = items[0].start;
        item_idx = 0;
  
        for (int i = 0; i < itemcnt; i++) {
          if (items[i].type == Trunc) {
            // Truncate at %< items.
            trunc_p = items[i].start;
            item_idx = i;
            break;
          }
        }
      }
  
      // If the truncation point we found is beyond the maximum
      // length of the string, truncate the end of the string.
      if (width - vim_strsize(trunc_p) >= maxwidth) {
        // If we are using a multi-byte encoding, walk from the beginning of the
        // string to find the last character that will fit.
        if (has_mbyte) {
          trunc_p = out;
          width = 0;
          for (;; ) {
            width += ptr2cells(trunc_p);
            if (width >= maxwidth)
              break;
  
            // Note: Only advance the pointer if the next
            //       character will fit in the available output space
            trunc_p += (*mb_ptr2len)(trunc_p);
          }
  
        // Otherwise put the truncation point at the end, leaving enough room
        // for a single-character truncation marker
        } else {
          trunc_p = out + maxwidth - 1;
        }
  
        // Ignore any items in the statusline that occur after
        // the truncation point
        for (int i = 0; i < itemcnt; i++) {
          if (items[i].start > trunc_p) {
            itemcnt = i;
            break;
          }
        }
  
        // Truncate the output
        *trunc_p++ = '>';
        *trunc_p = 0;
  
      // Truncate at the truncation point we found
      } else {
        // { Determine how many bytes to remove
        long trunc_len;
        if (has_mbyte) {
          trunc_len = 0;
          while (width >= maxwidth) {
            width     -= ptr2cells(trunc_p + trunc_len);
            trunc_len += (*mb_ptr2len)(trunc_p + trunc_len);
          }
        } else {
          // Truncate an extra character so we can insert our `<`.
          trunc_len = (width - maxwidth) + 1;
        }
        // }
  
        // { Truncate the string
        char_u *trunc_end_p = trunc_p + trunc_len;
        STRMOVE(trunc_p + 1, trunc_end_p);
  
        // Put a `<` to mark where we truncated at
        *trunc_p = '<';
  
        if (width + 1 < maxwidth) {
          // Advance the pointer to the end of the string
          trunc_p = trunc_p + STRLEN(trunc_p);
        }
  
        // Fill up for half a double-wide character.
        while (++width < maxwidth) {
          *trunc_p++ = fillchar;
          *trunc_p = NUL;
        }
        // }
  
        // { Change the start point for items based on
        //  their position relative to our truncation point
  
        // Note: The offset is one less than the truncation length because
        //       the truncation marker `<` is not counted.
        long item_offset = trunc_len - 1;
  
        for (int i = item_idx; i < itemcnt; i++) {
          // Items starting at or after the end of the truncated section need
          // to be moved backwards.
          if (items[i].start >= trunc_end_p) {
            items[i].start -= item_offset;
          // Anything inside the truncated area is set to start
          // at the `<` truncation character.
          } else {
            items[i].start = trunc_p;
          }
        }
        // }
      }
      width = maxwidth;
  
    // If there is room left in our statusline, and room left in our buffer,
    // add characters at the separate marker (if there is one) to
    // fill up the available space.
    } else if (width < maxwidth
               && STRLEN(out) + (size_t)(maxwidth - width) + 1 < outlen) {
      // Find how many separators there are, which we will use when
      // figuring out how many groups there are.
      int num_separators = 0;
      for (int i = 0; i < itemcnt; i++) {
        if (items[i].type == Separate) {
          num_separators++;
        }
      }
  
      // If we have separated groups, then we deal with it now
      if (num_separators) {
        // Create an array of the start location for each
        // separator mark.
        int separator_locations[STL_MAX_ITEM];
        int index = 0;
        for (int i = 0; i < itemcnt; i++) {
          if (items[i].type == Separate) {
            separator_locations[index] = i;
            index++;
          }
        }
  
        int standard_spaces = (maxwidth - width) / num_separators;
        int final_spaces = (maxwidth - width) -
          standard_spaces * (num_separators - 1);
  
        for (int i = 0; i < num_separators; i++) {
          int dislocation = (i == (num_separators - 1))
                            ? final_spaces : standard_spaces;
          char_u *seploc = items[separator_locations[i]].start + dislocation;
          STRMOVE(seploc, items[separator_locations[i]].start);
          for (char_u *s = items[separator_locations[i]].start; s < seploc; s++) {
            *s = fillchar;
          }
  
          for (int item_idx = separator_locations[i] + 1;
               item_idx < itemcnt;
               item_idx++) {
            items[item_idx].start += dislocation;
          }
        }
  
        width = maxwidth;
      }
    }
  
    // Store the info about highlighting.
    if (hltab != NULL) {
      struct stl_hlrec *sp = hltab;
      for (long l = 0; l < itemcnt; l++) {
        if (items[l].type == Highlight) {
          sp->start = items[l].start;
          sp->userhl = items[l].minwid;
          sp++;
        }
      }
      sp->start = NULL;
      sp->userhl = 0;
    }
  
    // Store the info about tab pages labels.
    if (tabtab != NULL) {
      StlClickRecord *cur_tab_rec = tabtab;
      for (long l = 0; l < itemcnt; l++) {
        if (items[l].type == TabPage) {
          cur_tab_rec->start = (char *)items[l].start;
          if (items[l].minwid == 0) {
            cur_tab_rec->def.type = kStlClickDisabled;
            cur_tab_rec->def.tabnr = 0;
          } else {
            int tabnr = items[l].minwid;
            if (items[l].minwid > 0) {
              cur_tab_rec->def.type = kStlClickTabSwitch;
            } else {
              cur_tab_rec->def.type = kStlClickTabClose;
              tabnr = -tabnr;
            }
            cur_tab_rec->def.tabnr = tabnr;
          }
          cur_tab_rec->def.func = NULL;
          cur_tab_rec++;
        } else if (items[l].type == ClickFunc) {
          cur_tab_rec->start = (char *)items[l].start;
          cur_tab_rec->def.type = kStlClickFuncRun;
          cur_tab_rec->def.tabnr = items[l].minwid;
          cur_tab_rec->def.func = items[l].cmd;
          cur_tab_rec++;
        }
      }
      cur_tab_rec->start = NULL;
      cur_tab_rec->def.type = kStlClickDisabled;
      cur_tab_rec->def.tabnr = 0;
      cur_tab_rec->def.func = NULL;
    }
  
    return width;
  }
  
  /*
   * Get relative cursor position in window into "buf[buflen]", in the form 99%,
   * using "Top", "Bot" or "All" when appropriate.
   */
  void get_rel_pos(win_T *wp, char_u *buf, int buflen)
  {
    // Need at least 3 chars for writing.
    if (buflen < 3) {
      return;
    }
  
    long above;          /* number of lines above window */
    long below;          /* number of lines below window */
  
    above = wp->w_topline - 1;
    above += diff_check_fill(wp, wp->w_topline) - wp->w_topfill;
    if (wp->w_topline == 1 && wp->w_topfill >= 1) {
      // All buffer lines are displayed and there is an indication
      // of filler lines, that can be considered seeing all lines.
      above = 0;
    }
    below = wp->w_buffer->b_ml.ml_line_count - wp->w_botline + 1;
    if (below <= 0)
      STRLCPY(buf, (above == 0 ? _("All") : _("Bot")), buflen);
    else if (above <= 0)
      STRLCPY(buf, _("Top"), buflen);
    else
      vim_snprintf((char *)buf, (size_t)buflen, "%2d%%", above > 1000000L
          ? (int)(above / ((above + below) / 100L))
          : (int)(above * 100L / (above + below)));
  }
  
  /// Append (file 2 of 8) to "buf[buflen]", if editing more than one file.
  ///
  /// @param          wp        window whose buffers to check
  /// @param[in,out]  buf       string buffer to add the text to
  /// @param          buflen    length of the string buffer
  /// @param          add_file  if true, add "file" before the arg number
  ///
  /// @return true if it was appended.
  static bool append_arg_number(win_T *wp, char_u *buf, int buflen, bool add_file)
    FUNC_ATTR_NONNULL_ALL
  {
    // Nothing to do
    if (ARGCOUNT <= 1) {
      return false;
    }
  
    char_u *p = buf + STRLEN(buf);  // go to the end of the buffer
  
    // Early out if the string is getting too long
    if (p - buf + 35 >= buflen) {
      return false;
    }
  
    *p++ = ' ';
    *p++ = '(';
    if (add_file) {
      STRCPY(p, "file ");
      p += 5;
    }
    vim_snprintf((char *)p, (size_t)(buflen - (p - buf)),
                 wp->w_arg_idx_invalid
                 ? "(%d) of %d)"
                 : "%d of %d)", wp->w_arg_idx + 1, ARGCOUNT);
    return true;
  }
  
  /*
   * Make "ffname" a full file name, set "sfname" to "ffname" if not NULL.
   * "ffname" becomes a pointer to allocated memory (or NULL).
   */
  void fname_expand(buf_T *buf, char_u **ffname, char_u **sfname)
  {
    if (*ffname == NULL)          /* if no file name given, nothing to do */
      return;
    if (*sfname == NULL)          /* if no short file name given, use ffname */
      *sfname = *ffname;
    *ffname = (char_u *)fix_fname((char *)*ffname);     /* expand to full path */
  
  #ifdef WIN32
    if (!buf->b_p_bin) {
      // If the file name is a shortcut file, use the file it links to.
      char *rfname = os_resolve_shortcut((const char *)(*ffname));
      if (rfname != NULL) {
        xfree(*ffname);
        *ffname = (char_u *)rfname;
        *sfname = (char_u *)rfname;
      }
    }
  #endif
  }
  
  /*
   * Get the file name for an argument list entry.
   */
  char_u *alist_name(aentry_T *aep)
  {
    buf_T       *bp;
  
    /* Use the name from the associated buffer if it exists. */
    bp = buflist_findnr(aep->ae_fnum);
    if (bp == NULL || bp->b_fname == NULL)
      return aep->ae_fname;
    return bp->b_fname;
  }
  
  /*
   * do_arg_all(): Open up to 'count' windows, one for each argument.
   */
  void 
  do_arg_all (
      int count,
      int forceit,                    /* hide buffers in current windows */
      int keep_tabs                  /* keep current tabs, for ":tab drop file" */
  )
  {
    int i;
    char_u      *opened;          /* Array of weight for which args are open:
                                   *  0: not opened
                                   *  1: opened in other tab
                                   *  2: opened in curtab
                                   *  3: opened in curtab and curwin
                                   */
    int opened_len;               /* length of opened[] */
    int use_firstwin = FALSE;             /* use first window for arglist */
    int split_ret = OK;
    bool p_ea_save;
    alist_T     *alist;           /* argument list to be used */
    buf_T       *buf;
    tabpage_T   *tpnext;
    int had_tab = cmdmod.tab;
    win_T       *old_curwin, *last_curwin;
    tabpage_T   *old_curtab, *last_curtab;
    win_T       *new_curwin = NULL;
    tabpage_T   *new_curtab = NULL;
  
    assert(firstwin != NULL);  // satisfy coverity
  
    if (ARGCOUNT <= 0) {
      /* Don't give an error message.  We don't want it when the ":all"
       * command is in the .vimrc. */
      return;
    }
    setpcmark();
  
    opened_len = ARGCOUNT;
    opened = xcalloc((size_t)opened_len, 1);
  
    /* Autocommands may do anything to the argument list.  Make sure it's not
     * freed while we are working here by "locking" it.  We still have to
     * watch out for its size to be changed. */
    alist = curwin->w_alist;
    ++alist->al_refcount;
  
    old_curwin = curwin;
    old_curtab = curtab;
  
  
    /*
     * Try closing all windows that are not in the argument list.
     * Also close windows that are not full width;
     * When 'hidden' or "forceit" set the buffer becomes hidden.
     * Windows that have a changed buffer and can't be hidden won't be closed.
     * When the ":tab" modifier was used do this for all tab pages.
     */
    if (had_tab > 0)
      goto_tabpage_tp(first_tabpage, TRUE, TRUE);
    for (;; ) {
      win_T *wpnext = NULL;
      tpnext = curtab->tp_next;
      for (win_T *wp = firstwin; wp != NULL; wp = wpnext) {
        wpnext = wp->w_next;
        buf = wp->w_buffer;
        if (buf->b_ffname == NULL
            || (!keep_tabs && (buf->b_nwindows > 1 || wp->w_width != Columns))) {
          i = opened_len;
        } else {
          // check if the buffer in this window is in the arglist
          for (i = 0; i < opened_len; ++i) {
            if (i < alist->al_ga.ga_len
                && (AARGLIST(alist)[i].ae_fnum == buf->b_fnum
                    || path_full_compare(alist_name(&AARGLIST(alist)[i]),
                                         buf->b_ffname, true) & kEqualFiles)) {
              int weight = 1;
  
              if (old_curtab == curtab) {
                ++weight;
                if (old_curwin == wp)
                  ++weight;
              }
  
              if (weight > (int)opened[i]) {
                opened[i] = (char_u)weight;
                if (i == 0) {
                  if (new_curwin != NULL)
                    new_curwin->w_arg_idx = opened_len;
                  new_curwin = wp;
                  new_curtab = curtab;
                }
              } else if (keep_tabs)
                i = opened_len;
  
              if (wp->w_alist != alist) {
                /* Use the current argument list for all windows
                 * containing a file from it. */
                alist_unlink(wp->w_alist);
                wp->w_alist = alist;
                ++wp->w_alist->al_refcount;
              }
              break;
            }
          }
        }
        wp->w_arg_idx = i;
  
        if (i == opened_len && !keep_tabs) {    // close this window
          if (buf_hide(buf) || forceit || buf->b_nwindows > 1
              || !bufIsChanged(buf)) {
            /* If the buffer was changed, and we would like to hide it,
             * try autowriting. */
            if (!buf_hide(buf) && buf->b_nwindows <= 1 && bufIsChanged(buf)) {
              bufref_T bufref;
              set_bufref(&bufref, buf);
              (void)autowrite(buf, false);
              // Check if autocommands removed the window.
              if (!win_valid(wp) || !bufref_valid(&bufref)) {
                wpnext = firstwin;  // Start all over...
                continue;
              }
            }
            // don't close last window
            if (ONE_WINDOW
                && (first_tabpage->tp_next == NULL || !had_tab)) {
              use_firstwin = true;
            } else {
              win_close(wp, !buf_hide(buf) && !bufIsChanged(buf));
              // check if autocommands removed the next window
              if (!win_valid(wpnext)) {
                // start all over...
                wpnext = firstwin;                
              }
            }
          }
        }
      }
  
      /* Without the ":tab" modifier only do the current tab page. */
      if (had_tab == 0 || tpnext == NULL)
        break;
  
      /* check if autocommands removed the next tab page */
      if (!valid_tabpage(tpnext))
        tpnext = first_tabpage;           /* start all over...*/
      goto_tabpage_tp(tpnext, TRUE, TRUE);
    }
  
    /*
     * Open a window for files in the argument list that don't have one.
     * ARGCOUNT may change while doing this, because of autocommands.
     */
    if (count > opened_len || count <= 0)
      count = opened_len;
  
    /* Don't execute Win/Buf Enter/Leave autocommands here. */
    ++autocmd_no_enter;
    ++autocmd_no_leave;
    last_curwin = curwin;
    last_curtab = curtab;
    win_enter(lastwin, false);
    // ":drop all" should re-use an empty window to avoid "--remote-tab"
    // leaving an empty tab page when executed locally.
    if (keep_tabs && BUFEMPTY() && curbuf->b_nwindows == 1
        && curbuf->b_ffname == NULL && !curbuf->b_changed) {
      use_firstwin = true;
    }
  
    for (i = 0; i < count && i < opened_len && !got_int; i++) {
      if (alist == &global_alist && i == global_alist.al_ga.ga_len - 1) {
        arg_had_last = true;
      }
      if (opened[i] > 0) {
        /* Move the already present window to below the current window */
        if (curwin->w_arg_idx != i) {
          FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
            if (wp->w_arg_idx == i) {
              if (keep_tabs) {
                new_curwin = wp;
                new_curtab = curtab;
              } else {
                win_move_after(wp, curwin);
              }
              break;
            }
          }
        }
      } else if (split_ret == OK) {
        if (!use_firstwin) {              /* split current window */
          p_ea_save = p_ea;
          p_ea = true;                    /* use space from all windows */
          split_ret = win_split(0, WSP_ROOM | WSP_BELOW);
          p_ea = p_ea_save;
          if (split_ret == FAIL)
            continue;
        } else        /* first window: do autocmd for leaving this buffer */
          --autocmd_no_leave;
  
        /*
         * edit file "i"
         */
        curwin->w_arg_idx = i;
        if (i == 0) {
          new_curwin = curwin;
          new_curtab = curtab;
        }
        (void)do_ecmd(0, alist_name(&AARGLIST(alist)[i]), NULL, NULL, ECMD_ONE,
                      ((buf_hide(curwin->w_buffer)
                        || bufIsChanged(curwin->w_buffer))
                       ? ECMD_HIDE : 0) + ECMD_OLDBUF,
                      curwin);
        if (use_firstwin) {
          autocmd_no_leave++;
        }
        use_firstwin = false;
      }
      os_breakcheck();
  
      /* When ":tab" was used open a new tab for a new window repeatedly. */
      if (had_tab > 0 && tabpage_index(NULL) <= p_tpm)
        cmdmod.tab = 9999;
    }
  
    /* Remove the "lock" on the argument list. */
    alist_unlink(alist);
  
    autocmd_no_enter--;
    // restore last referenced tabpage's curwin
    if (last_curtab != new_curtab) {
      if (valid_tabpage(last_curtab)) {
        goto_tabpage_tp(last_curtab, true, true);
      }
      if (win_valid(last_curwin)) {
        win_enter(last_curwin, false);
      }
    }
    // to window with first arg
    if (valid_tabpage(new_curtab)) {
      goto_tabpage_tp(new_curtab, true, true);
    }
    if (win_valid(new_curwin)) {
      win_enter(new_curwin, false);
    }
  
    --autocmd_no_leave;
    xfree(opened);
  }
  
  /*
   * Open a window for a number of buffers.
   */
  void ex_buffer_all(exarg_T *eap)
  {
    buf_T       *buf;
    win_T       *wp, *wpnext;
    int split_ret = OK;
    bool p_ea_save;
    int open_wins = 0;
    int r;
    long count;                   // Maximum number of windows to open.
    int all;                      // When TRUE also load inactive buffers.
    int had_tab = cmdmod.tab;
    tabpage_T   *tpnext;
  
    if (eap->addr_count == 0)     /* make as many windows as possible */
      count = 9999;
    else
      count = eap->line2;         /* make as many windows as specified */
    if (eap->cmdidx == CMD_unhide || eap->cmdidx == CMD_sunhide)
      all = FALSE;
    else
      all = TRUE;
  
    setpcmark();
  
  
    /*
     * Close superfluous windows (two windows for the same buffer).
     * Also close windows that are not full-width.
     */
    if (had_tab > 0)
      goto_tabpage_tp(first_tabpage, TRUE, TRUE);
    for (;; ) {
      tpnext = curtab->tp_next;
      for (wp = firstwin; wp != NULL; wp = wpnext) {
        wpnext = wp->w_next;
        if ((wp->w_buffer->b_nwindows > 1
             || ((cmdmod.split & WSP_VERT)
                 ? wp->w_height + wp->w_status_height < Rows - p_ch
                 - tabline_height()
                 : wp->w_width != Columns)
             || (had_tab > 0 && wp != firstwin))
            && !ONE_WINDOW
            && !(wp->w_closing || wp->w_buffer->b_locked > 0)
            ) {
          win_close(wp, false);
          wpnext = firstwin;              // just in case an autocommand does
                                          // something strange with windows
          tpnext = first_tabpage;         // start all over...
          open_wins = 0;
        } else
          ++open_wins;
      }
  
      /* Without the ":tab" modifier only do the current tab page. */
      if (had_tab == 0 || tpnext == NULL)
        break;
      goto_tabpage_tp(tpnext, TRUE, TRUE);
    }
  
    /*
     * Go through the buffer list.  When a buffer doesn't have a window yet,
     * open one.  Otherwise move the window to the right position.
     * Watch out for autocommands that delete buffers or windows!
     */
    /* Don't execute Win/Buf Enter/Leave autocommands here. */
    ++autocmd_no_enter;
    win_enter(lastwin, false);
    ++autocmd_no_leave;
    for (buf = firstbuf; buf != NULL && open_wins < count; buf = buf->b_next) {
      /* Check if this buffer needs a window */
      if ((!all && buf->b_ml.ml_mfp == NULL) || !buf->b_p_bl)
        continue;
  
      if (had_tab != 0) {
        /* With the ":tab" modifier don't move the window. */
        if (buf->b_nwindows > 0)
          wp = lastwin;               /* buffer has a window, skip it */
        else
          wp = NULL;
      } else {
        /* Check if this buffer already has a window */
        for (wp = firstwin; wp != NULL; wp = wp->w_next)
          if (wp->w_buffer == buf)
            break;
        /* If the buffer already has a window, move it */
        if (wp != NULL)
          win_move_after(wp, curwin);
      }
  
      if (wp == NULL && split_ret == OK) {
        bufref_T bufref;
        set_bufref(&bufref, buf);
        // Split the window and put the buffer in it.
        p_ea_save = p_ea;
        p_ea = true;                      /* use space from all windows */
        split_ret = win_split(0, WSP_ROOM | WSP_BELOW);
        ++open_wins;
        p_ea = p_ea_save;
        if (split_ret == FAIL)
          continue;
  
        /* Open the buffer in this window. */
        swap_exists_action = SEA_DIALOG;
        set_curbuf(buf, DOBUF_GOTO);
        if (!bufref_valid(&bufref)) {
          // Autocommands deleted the buffer.
          swap_exists_action = SEA_NONE;
          break;
        }
        if (swap_exists_action == SEA_QUIT) {
          cleanup_T cs;
  
          /* Reset the error/interrupt/exception state here so that
           * aborting() returns FALSE when closing a window. */
          enter_cleanup(&cs);
  
          // User selected Quit at ATTENTION prompt; close this window.
          win_close(curwin, true);
          open_wins--;
          swap_exists_action = SEA_NONE;
          swap_exists_did_quit = TRUE;
  
          /* Restore the error/interrupt/exception state if not
           * discarded by a new aborting error, interrupt, or uncaught
           * exception. */
          leave_cleanup(&cs);
        } else
          handle_swap_exists(NULL);
      }
  
      os_breakcheck();
      if (got_int) {
        (void)vgetc();            /* only break the file loading, not the rest */
        break;
      }
      /* Autocommands deleted the buffer or aborted script processing!!! */
      if (aborting())
        break;
      /* When ":tab" was used open a new tab for a new window repeatedly. */
      if (had_tab > 0 && tabpage_index(NULL) <= p_tpm)
        cmdmod.tab = 9999;
    }
    --autocmd_no_enter;
    win_enter(firstwin, false);           /* back to first window */
    --autocmd_no_leave;
  
    /*
     * Close superfluous windows.
     */
    for (wp = lastwin; open_wins > count; ) {
      r = (buf_hide(wp->w_buffer) || !bufIsChanged(wp->w_buffer)
           || autowrite(wp->w_buffer, false) == OK);
      if (!win_valid(wp)) {
        /* BufWrite Autocommands made the window invalid, start over */
        wp = lastwin;
      } else if (r) {
        win_close(wp, !buf_hide(wp->w_buffer));
        open_wins--;
        wp = lastwin;
      } else {
        wp = wp->w_prev;
        if (wp == NULL)
          break;
      }
    }
  }
  
  
  
  /*
   * do_modelines() - process mode lines for the current file
   *
   * "flags" can be:
   * OPT_WINONLY	    only set options local to window
   * OPT_NOWIN	    don't set options local to window
   *
   * Returns immediately if the "ml" option isn't set.
   */
  void do_modelines(int flags)
  {
    linenr_T lnum;
    int nmlines;
    static int entered = 0;
  
    if (!curbuf->b_p_ml || (nmlines = (int)p_mls) == 0)
      return;
  
    /* Disallow recursive entry here.  Can happen when executing a modeline
     * triggers an autocommand, which reloads modelines with a ":do". */
    if (entered)
      return;
  
    ++entered;
    for (lnum = 1; lnum <= curbuf->b_ml.ml_line_count && lnum <= nmlines;
         ++lnum)
      if (chk_modeline(lnum, flags) == FAIL)
        nmlines = 0;
  
    for (lnum = curbuf->b_ml.ml_line_count; lnum > 0 && lnum > nmlines
         && lnum > curbuf->b_ml.ml_line_count - nmlines; --lnum)
      if (chk_modeline(lnum, flags) == FAIL)
        nmlines = 0;
    --entered;
  }
  
  /*
   * chk_modeline() - check a single line for a mode string
   * Return FAIL if an error encountered.
   */
  static int 
  chk_modeline (
      linenr_T lnum,
      int flags                      /* Same as for do_modelines(). */
  )
  {
    char_u      *s;
    char_u      *e;
    char_u      *linecopy;                /* local copy of any modeline found */
    int prev;
    intmax_t vers;
    int end;
    int retval = OK;
    char_u      *save_sourcing_name;
    linenr_T save_sourcing_lnum;
    scid_T save_SID;
  
    prev = -1;
    for (s = ml_get(lnum); *s != NUL; ++s) {
      if (prev == -1 || ascii_isspace(prev)) {
        if ((prev != -1 && STRNCMP(s, "ex:", (size_t)3) == 0)
            || STRNCMP(s, "vi:", (size_t)3) == 0)
          break;
        /* Accept both "vim" and "Vim". */
        if ((s[0] == 'v' || s[0] == 'V') && s[1] == 'i' && s[2] == 'm') {
          if (s[3] == '<' || s[3] == '=' || s[3] == '>')
            e = s + 4;
          else
            e = s + 3;
          if (getdigits_safe(&e, &vers) != OK) {
            continue;
          }
  
          if (*e == ':'
              && (s[0] != 'V'
                  || STRNCMP(skipwhite(e + 1), "set", 3) == 0)
              && (s[3] == ':'
                  || (VIM_VERSION_100 >= vers && isdigit(s[3]))
                  || (VIM_VERSION_100 < vers && s[3] == '<')
                  || (VIM_VERSION_100 > vers && s[3] == '>')
                  || (VIM_VERSION_100 == vers && s[3] == '='))) {
            break;
          }
        }
      }
      prev = *s;
    }
  
    if (!*s) {
      return retval;
    }
  
    do                                  /* skip over "ex:", "vi:" or "vim:" */
      ++s;
    while (s[-1] != ':');
  
    s = linecopy = vim_strsave(s);      /* copy the line, it will change */
  
    save_sourcing_lnum = sourcing_lnum;
    save_sourcing_name = sourcing_name;
    sourcing_lnum = lnum;               /* prepare for emsg() */
    sourcing_name = (char_u *)"modelines";
  
    end = FALSE;
    while (end == FALSE) {
      s = skipwhite(s);
      if (*s == NUL)
        break;
  
      /*
       * Find end of set command: ':' or end of line.
       * Skip over "\:", replacing it with ":".
       */
      for (e = s; *e != ':' && *e != NUL; ++e)
        if (e[0] == '\\' && e[1] == ':')
          STRMOVE(e, e + 1);
      if (*e == NUL)
        end = TRUE;
  
      /*
       * If there is a "set" command, require a terminating ':' and
       * ignore the stuff after the ':'.
       * "vi:set opt opt opt: foo" -- foo not interpreted
       * "vi:opt opt opt: foo" -- foo interpreted
       * Accept "se" for compatibility with Elvis.
       */
      if (STRNCMP(s, "set ", (size_t)4) == 0
          || STRNCMP(s, "se ", (size_t)3) == 0) {
        if (*e != ':')                  /* no terminating ':'? */
          break;
        end = TRUE;
        s = vim_strchr(s, ' ') + 1;
      }
      *e = NUL;                         /* truncate the set command */
  
      if (*s != NUL) {                  /* skip over an empty "::" */
        save_SID = current_SID;
        current_SID = SID_MODELINE;
        retval = do_set(s, OPT_MODELINE | OPT_LOCAL | flags);
        current_SID = save_SID;
        if (retval == FAIL)                     /* stop if error found */
          break;
      }
      s = e + 1;                        /* advance to next part */
    }
  
    sourcing_lnum = save_sourcing_lnum;
    sourcing_name = save_sourcing_name;
  
    xfree(linecopy);
  
    return retval;
  }
  
  // Return true if "buf" is a help buffer.
  bool bt_help(const buf_T *const buf)
  {
    return buf != NULL && buf->b_help;
  }
  
  /*
   * Return special buffer name.
   * Returns NULL when the buffer has a normal file name.
   */
  char_u *buf_spname(buf_T *buf)
  {
    if (bt_quickfix(buf)) {
      win_T       *win;
      tabpage_T   *tp;
  
      /*
       * For location list window, w_llist_ref points to the location list.
       * For quickfix window, w_llist_ref is NULL.
       */
      if (find_win_for_buf(buf, &win, &tp) && win->w_llist_ref != NULL)
        return (char_u *)_(msg_loclist);
      else
        return (char_u *)_(msg_qflist);
    }
    /* There is no _file_ when 'buftype' is "nofile", b_sfname
     * contains the name as specified by the user */
    if (bt_nofile(buf)) {
      if (buf->b_sfname != NULL)
        return buf->b_sfname;
      return (char_u *)_("[Scratch]");
    }
    if (buf->b_fname == NULL)
      return (char_u *)_("[No Name]");
    return NULL;
  }
  
  /// Find a window for buffer "buf".
  /// If found true is returned and "wp" and "tp" are set to
  /// the window and tabpage.
  /// If not found, false is returned.
  ///
  /// @param       buf  buffer to find a window for
  /// @param[out]  wp   stores the found window
  /// @param[out]  tp   stores the found tabpage
  ///
  /// @return true if a window was found for the buffer.
  bool find_win_for_buf(buf_T *buf, win_T **wp, tabpage_T **tp)
  {
    *wp = NULL;
    *tp = NULL;
    FOR_ALL_TAB_WINDOWS(tp2, wp2) {
      if (wp2->w_buffer == buf) {
        *tp = tp2;
        *wp = wp2;
        return true;
      }
    }
    return false;
  }
  
  /*
   * Insert the sign into the signlist.
   */
  static void insert_sign(
      buf_T *buf,             /* buffer to store sign in */
      signlist_T *prev,       /* previous sign entry */
      signlist_T *next,       /* next sign entry */
      int id,                 /* sign ID */
      linenr_T lnum,          /* line number which gets the mark */
      int typenr              /* typenr of sign we are adding */
      )
  {
      signlist_T *newsign = xmalloc(sizeof(signlist_T));
      newsign->id = id;
      newsign->lnum = lnum;
      newsign->typenr = typenr;
      newsign->next = next;
  
      if (prev == NULL) {
          /* When adding first sign need to redraw the windows to create the
           * column for signs. */
          if (buf->b_signlist == NULL) {
              redraw_buf_later(buf, NOT_VALID);
              changed_cline_bef_curs();
          }
  
          /* first sign in signlist */
          buf->b_signlist = newsign;
      }
      else {
          prev->next = newsign;
      }
  }
  
  /*
   * Add the sign into the signlist. Find the right spot to do it though.
   */
  void buf_addsign(
      buf_T *buf,     /* buffer to store sign in */
      int id,         /* sign ID */
      linenr_T lnum,  /* line number which gets the mark */
      int typenr      /* typenr of sign we are adding */
      )
  {
      signlist_T *sign;  /* a sign in the signlist */
      signlist_T *prev;  /* the previous sign */
  
      prev = NULL;
      for (sign = buf->b_signlist; sign != NULL; sign = sign->next) {
          if (lnum == sign->lnum && id == sign->id) {
              sign->typenr = typenr;
              return;
          } else if ((lnum == sign->lnum && id != sign->id)
                     || (id < 0 && lnum < sign->lnum)) {  // attempt to keep signs sorted by lnum
              insert_sign(buf, prev, sign, id, lnum, typenr);
              return;
          }
          prev = sign;
      }
      insert_sign(buf, prev, sign, id, lnum, typenr);
  
      return;
  }
  
  // For an existing, placed sign "markId" change the type to "typenr".
  // Returns the line number of the sign, or zero if the sign is not found.
  linenr_T buf_change_sign_type(
      buf_T *buf,         /* buffer to store sign in */
      int markId,         /* sign ID */
      int typenr          /* typenr of sign we are adding */
      )
  {
      signlist_T *sign;  /* a sign in the signlist */
  
      for (sign = buf->b_signlist; sign != NULL; sign = sign->next) {
          if (sign->id == markId) {
              sign->typenr = typenr;
              return sign->lnum;
          }
      }
  
      return (linenr_T)0;
  }
  
  /// Gets a sign from a given line.
  /// In case of multiple signs, returns the most recently placed one.
  ///
  /// @param buf Buffer in which to search
  /// @param lnum Line in which to search
  /// @param type Type of sign to look for
  /// @return Identifier of the first matching sign, or 0
  int buf_getsigntype(buf_T *buf, linenr_T lnum, SignType type)
  {
      signlist_T *sign;  // a sign in a b_signlist
  
      for (sign = buf->b_signlist; sign != NULL; sign = sign->next) {
          if (sign->lnum == lnum
                  && (type == SIGN_ANY
                      || (type == SIGN_TEXT
                          && sign_get_text(sign->typenr) != NULL)
                      || (type == SIGN_LINEHL
                          && sign_get_attr(sign->typenr, SIGN_LINEHL) != 0)
                      || (type == SIGN_NUMHL
                          && sign_get_attr(sign->typenr, SIGN_NUMHL) != 0))) {
              return sign->typenr;
          }
      }
      return 0;
  }
  
  
  linenr_T buf_delsign(
          buf_T *buf, /* buffer sign is stored in */
          int id      /* sign id */
          )
  {
      signlist_T **lastp; /* pointer to pointer to current sign */
      signlist_T *sign;   /* a sign in a b_signlist */
      signlist_T *next;   /* the next sign in a b_signlist */
      linenr_T lnum;      /* line number whose sign was deleted */
  
      lastp = &buf->b_signlist;
      lnum = 0;
      for (sign = buf->b_signlist; sign != NULL; sign = next) {
          next = sign->next;
          if (sign->id == id) {
              *lastp = next;
              lnum = sign->lnum;
              xfree(sign);
              break;
          } else {
              lastp = &sign->next;
          }
      }
  
      /* When deleted the last sign needs to redraw the windows to remove the
       * sign column. */
      if (buf->b_signlist == NULL) {
          redraw_buf_later(buf, NOT_VALID);
          changed_cline_bef_curs();
      }
  
      return lnum;
  }
  
  
  /*
   * Find the line number of the sign with the requested id. If the sign does
   * not exist, return 0 as the line number. This will still let the correct file
   * get loaded.
   */
  int buf_findsign(
      buf_T *buf,      /* buffer to store sign in */
      int id          /* sign ID */
      )
  {
      signlist_T *sign;  /* a sign in the signlist */
  
      for (sign = buf->b_signlist; sign != NULL; sign = sign->next) {
          if (sign->id == id) {
              return (int)sign->lnum;
          }
      }
  
      return 0;
  }
  
  int buf_findsign_id(
      buf_T *buf,         /* buffer whose sign we are searching for */
      linenr_T lnum       /* line number of sign */
      )
  {
      signlist_T *sign;   /* a sign in the signlist */
  
      for (sign = buf->b_signlist; sign != NULL; sign = sign->next) {
          if (sign->lnum == lnum) {
              return sign->id;
          }
      }
  
      return 0;
  }
  
  
  /*
   * Delete signs in buffer "buf".
   */
  void buf_delete_signs(buf_T *buf)
  {
      signlist_T *next;
  
      // When deleting the last sign need to redraw the windows to remove the
      // sign column. Not when curwin is NULL (this means we're exiting).
      if (buf->b_signlist != NULL && curwin != NULL){
        redraw_buf_later(buf, NOT_VALID);
        changed_cline_bef_curs();
      }
  
      while (buf->b_signlist != NULL) {
          next = buf->b_signlist->next;
          xfree(buf->b_signlist);
          buf->b_signlist = next;
      }
  }
  
  /*
   * Delete all signs in all buffers.
   */
  void buf_delete_all_signs(void)
  {
    FOR_ALL_BUFFERS(buf) {
      if (buf->b_signlist != NULL) {
        buf_delete_signs(buf);
      }
    }
  }
  
  /*
   * List placed signs for "rbuf".  If "rbuf" is NULL do it for all buffers.
   */
  void sign_list_placed(buf_T *rbuf)
  {
      buf_T *buf;
      signlist_T *p;
      char lbuf[BUFSIZ];
  
      MSG_PUTS_TITLE(_("\n--- Signs ---"));
      msg_putchar('\n');
      if (rbuf == NULL) {
          buf = firstbuf;
      } else {
          buf = rbuf;
      }
      while (buf != NULL && !got_int) {
          if (buf->b_signlist != NULL) {
              vim_snprintf(lbuf, BUFSIZ, _("Signs for %s:"), buf->b_fname);
              MSG_PUTS_ATTR(lbuf, HL_ATTR(HLF_D));
              msg_putchar('\n');
          }
          for (p = buf->b_signlist; p != NULL && !got_int; p = p->next) {
              vim_snprintf(lbuf, BUFSIZ, _("    line=%" PRId64 "  id=%d  name=%s"),
                      (int64_t)p->lnum, p->id, sign_typenr2name(p->typenr));
              MSG_PUTS(lbuf);
              msg_putchar('\n');
          }
          if (rbuf != NULL) {
              break;
          }
          buf = buf->b_next;
      }
  }
  
  /*
   * Adjust a placed sign for inserted/deleted lines.
   */
  void sign_mark_adjust(linenr_T line1, linenr_T line2, long amount, long amount_after)
  {
      signlist_T *sign;  /* a sign in a b_signlist */
  
      for (sign = curbuf->b_signlist; sign != NULL; sign = sign->next) {
          if (sign->lnum >= line1 && sign->lnum <= line2) {
              if (amount == MAXLNUM) {
                  sign->lnum = line1;
              } else {
                  sign->lnum += amount;
              }
          }
          else if (sign->lnum > line2)
              sign->lnum += amount_after;
      }
  }
  
  // bufhl: plugin highlights associated with a buffer
  
  /// Get reference to line in kbtree_t
  ///
  /// @param b the three
  /// @param line the linenumber to lookup
  /// @param put if true, put a new line when not found
  ///            if false, return NULL when not found
  BufhlLine *bufhl_tree_ref(BufhlInfo *b, linenr_T line, bool put)
  {
    BufhlLine t = BUFHLLINE_INIT(line);
  
    // kp_put() only works if key is absent, try get first
    BufhlLine **pp = kb_get(bufhl, b, &t);
    if (pp) {
      return *pp;
    } else if (!put) {
      return NULL;
    }
  
    BufhlLine *p = xmalloc(sizeof(*p));
    *p = (BufhlLine)BUFHLLINE_INIT(line);
    kb_put(bufhl, b, p);
    return p;
  }
  
  /// Adds a highlight to buffer.
  ///
  /// Unlike matchaddpos() highlights follow changes to line numbering (as lines
  /// are inserted/removed above the highlighted line), like signs and marks do.
  ///
  /// When called with "src_id" set to 0, a unique source id is generated and
  /// returned. Succesive calls can pass it in as "src_id" to add new highlights
  /// to the same source group. All highlights in the same group can be cleared
  /// at once. If the highlight never will be manually deleted pass in -1 for
  /// "src_id"
  ///
  /// if "hl_id" or "lnum" is invalid no highlight is added, but a new src_id
  /// is still returned.
  ///
  /// @param buf The buffer to add highlights to
  /// @param src_id src_id to use or 0 to use a new src_id group,
  ///               or -1 for ungrouped highlight.
  /// @param hl_id Id of the highlight group to use
  /// @param lnum The line to highlight
  /// @param col_start First column to highlight
  /// @param col_end The last column to highlight,
  ///                or -1 to highlight to end of line
  /// @return The src_id that was used
  int bufhl_add_hl(buf_T *buf,
                   int src_id,
                   int hl_id,
                   linenr_T lnum,
                   colnr_T col_start,
                   colnr_T col_end) {
    static int next_src_id = 1;
    if (src_id == 0) {
      src_id = next_src_id++;
    }
    if (hl_id <= 0) {
        // no highlight group or invalid line, just return src_id
        return src_id;
    }
  
    BufhlLine *lineinfo = bufhl_tree_ref(&buf->b_bufhl_info, lnum, true);
  
    BufhlItem *hlentry = kv_pushp(lineinfo->items);
    hlentry->src_id = src_id;
    hlentry->hl_id = hl_id;
    hlentry->start = col_start;
    hlentry->stop = col_end;
  
    if (0 < lnum && lnum <= buf->b_ml.ml_line_count) {
      changed_lines_buf(buf, lnum, lnum+1, 0);
      redraw_buf_later(buf, VALID);
    }
    return src_id;
  }
  
  /// Add highlighting to a buffer, bounded by two cursor positions,
  /// with an offset.
  ///
  /// @param buf Buffer to add highlights to
  /// @param src_id src_id to use or 0 to use a new src_id group,
  ///               or -1 for ungrouped highlight.
  /// @param hl_id Highlight group id
  /// @param pos_start Cursor position to start the hightlighting at
  /// @param pos_end Cursor position to end the highlighting at
  /// @param offset Move the whole highlighting this many columns to the right
  void bufhl_add_hl_pos_offset(buf_T *buf,
                               int src_id,
                               int hl_id,
                               lpos_T pos_start,
                               lpos_T pos_end,
                               colnr_T offset)
  {
    colnr_T hl_start = 0;
    colnr_T hl_end = 0;
  
    for (linenr_T lnum = pos_start.lnum; lnum <= pos_end.lnum; lnum ++) {
      if (pos_start.lnum < lnum && lnum < pos_end.lnum) {
        hl_start = offset;
        hl_end = MAXCOL;
      } else if (lnum == pos_start.lnum && lnum < pos_end.lnum) {
        hl_start = pos_start.col + offset + 1;
        hl_end = MAXCOL;
      } else if (pos_start.lnum < lnum && lnum == pos_end.lnum) {
        hl_start = offset;
        hl_end = pos_end.col + offset;
      } else if (pos_start.lnum == lnum && pos_end.lnum == lnum) {
        hl_start = pos_start.col + offset + 1;
        hl_end = pos_end.col + offset;
      }
      (void)bufhl_add_hl(buf, src_id, hl_id, lnum, hl_start, hl_end);
    }
  }
  
  int bufhl_add_virt_text(buf_T *buf,
                          int src_id,
                          linenr_T lnum,
                          VirtText virt_text)
  {
    static int next_src_id = 1;
    if (src_id == 0) {
      src_id = next_src_id++;
    }
  
    BufhlLine *lineinfo = bufhl_tree_ref(&buf->b_bufhl_info, lnum, true);
  
    bufhl_clear_virttext(&lineinfo->virt_text);
    if (kv_size(virt_text) > 0) {
      lineinfo->virt_text_src = src_id;
      lineinfo->virt_text = virt_text;
    } else {
      lineinfo->virt_text_src = 0;
      // currently not needed, but allow a future caller with
      // 0 size and non-zero capacity
      kv_destroy(virt_text);
    }
  
    if (0 < lnum && lnum <= buf->b_ml.ml_line_count) {
      changed_lines_buf(buf, lnum, lnum+1, 0);
      redraw_buf_later(buf, VALID);
    }
    return src_id;
  }
  
  static void bufhl_clear_virttext(VirtText *text)
  {
    for (size_t i = 0; i < kv_size(*text); i++) {
      xfree(kv_A(*text, i).text);
    }
    kv_destroy(*text);
    *text = (VirtText)KV_INITIAL_VALUE;
  }
  
  /// Clear bufhl highlights from a given source group and range of lines.
  ///
  /// @param buf The buffer to remove highlights from
  /// @param src_id highlight source group to clear, or -1 to clear all groups.
  /// @param line_start first line to clear
  /// @param line_end last line to clear or MAXLNUM to clear to end of file.
  void bufhl_clear_line_range(buf_T *buf,
                              int src_id,
                              linenr_T line_start,
                              linenr_T line_end)
  {
    linenr_T first_changed = MAXLNUM, last_changed = -1;
  
    kbitr_t(bufhl) itr;
    BufhlLine *l, t = BUFHLLINE_INIT(line_start);
    if (!kb_itr_get(bufhl, &buf->b_bufhl_info, &t, &itr)) {
      kb_itr_next(bufhl, &buf->b_bufhl_info, &itr);
    }
    for (; kb_itr_valid(&itr); kb_itr_next(bufhl, &buf->b_bufhl_info, &itr)) {
      l = kb_itr_key(&itr);
      linenr_T line = l->line;
      if (line > line_end) {
        break;
      }
      if (line_start <= line) {
        BufhlLineStatus status = bufhl_clear_line(l, src_id, line);
        if (status != kBLSUnchanged) {
          if (line > last_changed) {
            last_changed = line;
          }
          if (line < first_changed) {
            first_changed = line;
          }
        }
        if (status == kBLSDeleted) {
          kb_del_itr(bufhl, &buf->b_bufhl_info, &itr);
          xfree(l);
        }
      }
    }
  
    if (last_changed != -1) {
      changed_lines_buf(buf, first_changed, last_changed+1, 0);
      redraw_buf_later(buf, VALID);
    }
  }
  
  /// Clear bufhl highlights from a given source group and given line
  ///
  /// @param bufhl_info The highlight info for the buffer
  /// @param src_id Highlight source group to clear, or -1 to clear all groups.
  /// @param lnum Linenr where the highlight should be cleared
  static BufhlLineStatus bufhl_clear_line(BufhlLine *lineinfo, int src_id,
                                          linenr_T lnum)
  {
    BufhlLineStatus changed = kBLSUnchanged;
    size_t oldsize = kv_size(lineinfo->items);
    if (src_id < 0) {
      kv_size(lineinfo->items) = 0;
    } else {
      size_t newidx = 0;
      for (size_t i = 0; i < kv_size(lineinfo->items); i++) {
        if (kv_A(lineinfo->items, i).src_id != src_id) {
          if (i != newidx) {
            kv_A(lineinfo->items, newidx) = kv_A(lineinfo->items, i);
          }
          newidx++;
        }
      }
      kv_size(lineinfo->items) = newidx;
    }
    if (kv_size(lineinfo->items) != oldsize) {
      changed = kBLSChanged;
    }
  
    if (kv_size(lineinfo->virt_text) != 0
        && (src_id < 0 || src_id == lineinfo->virt_text_src)) {
      bufhl_clear_virttext(&lineinfo->virt_text);
      lineinfo->virt_text_src = 0;
      changed = kBLSChanged;
    }
  
    if (kv_size(lineinfo->items) == 0 && kv_size(lineinfo->virt_text) == 0) {
      kv_destroy(lineinfo->items);
      return kBLSDeleted;
    }
    return changed;
  }
  
  
  /// Remove all highlights and free the highlight data
  void bufhl_clear_all(buf_T *buf)
  {
    bufhl_clear_line_range(buf, -1, 1, MAXLNUM);
    kb_destroy(bufhl, (&buf->b_bufhl_info));
    kb_init(&buf->b_bufhl_info);
    kv_destroy(buf->b_bufhl_move_space);
    kv_init(buf->b_bufhl_move_space);
  }
  
  /// Adjust a placed highlight for inserted/deleted lines.
  void bufhl_mark_adjust(buf_T* buf,
                         linenr_T line1,
                         linenr_T line2,
                         long amount,
                         long amount_after,
                         bool end_temp)
  {
    kbitr_t(bufhl) itr;
    BufhlLine *l, t = BUFHLLINE_INIT(line1);
    if (end_temp && amount < 0) {
      // Move all items from b_bufhl_move_space to the btree.
      for (size_t i = 0; i < kv_size(buf->b_bufhl_move_space); i++) {
        l = kv_A(buf->b_bufhl_move_space, i);
        l->line += amount;
        kb_put(bufhl, &buf->b_bufhl_info, l);
      }
      kv_size(buf->b_bufhl_move_space) = 0;
      return;
    }
  
    if (!kb_itr_get(bufhl, &buf->b_bufhl_info, &t, &itr)) {
      kb_itr_next(bufhl, &buf->b_bufhl_info, &itr);
    }
    for (; kb_itr_valid(&itr); kb_itr_next(bufhl, &buf->b_bufhl_info, &itr)) {
      l = kb_itr_key(&itr);
      if (l->line >= line1 && l->line <= line2) {
        if (end_temp && amount > 0) {
          kb_del_itr(bufhl, &buf->b_bufhl_info, &itr);
          kv_push(buf->b_bufhl_move_space, l);
        }
        if (amount == MAXLNUM) {
          if (bufhl_clear_line(l, -1, l->line) == kBLSDeleted) {
            kb_del_itr(bufhl, &buf->b_bufhl_info, &itr);
            xfree(l);
          } else {
            assert(false);
          }
        } else {
          l->line += amount;
        }
      } else if (l->line > line2) {
        if (amount_after == 0) {
          break;
        }
        l->line += amount_after;
      }
    }
  }
  
  
  /// Get highlights to display at a specific line
  ///
  /// @param buf The buffer handle
  /// @param lnum The line number
  /// @param[out] info The highligts for the line
  /// @return true if there was highlights to display
  bool bufhl_start_line(buf_T *buf, linenr_T lnum, BufhlLineInfo *info)
  {
    BufhlLine *lineinfo = bufhl_tree_ref(&buf->b_bufhl_info, lnum, false);
    if (!lineinfo) {
      return false;
    }
    info->valid_to = -1;
    info->line = lineinfo;
    return true;
  }
  
  /// get highlighting at column col
  ///
  /// It is is assumed this will be called with
  /// non-decreasing column nrs, so that it is
  /// possible to only recalculate highlights
  /// at endpoints.
  ///
  /// @param info The info returned by bufhl_start_line
  /// @param col The column to get the attr for
  /// @return The highilight attr to display at the column
  int bufhl_get_attr(BufhlLineInfo *info, colnr_T col)
  {
    if (col <= info->valid_to) {
      return info->current;
    }
    int attr = 0;
    info->valid_to = MAXCOL;
    for (size_t i = 0; i < kv_size(info->line->items); i++) {
      BufhlItem entry = kv_A(info->line->items, i);
      if (entry.start <= col && col <= entry.stop) {
        int entry_attr = syn_id2attr(entry.hl_id);
        attr = hl_combine_attr(attr, entry_attr);
        if (entry.stop < info->valid_to) {
          info->valid_to = entry.stop;
        }
      } else if (col < entry.start && entry.start-1 < info->valid_to) {
        info->valid_to = entry.start-1;
      }
    }
    info->current = attr;
    return attr;
  }
  
  
  /*
   * Set 'buflisted' for curbuf to "on" and trigger autocommands if it changed.
   */
  void set_buflisted(int on)
  {
    if (on != curbuf->b_p_bl) {
      curbuf->b_p_bl = on;
      if (on)
        apply_autocmds(EVENT_BUFADD, NULL, NULL, FALSE, curbuf);
      else
        apply_autocmds(EVENT_BUFDELETE, NULL, NULL, FALSE, curbuf);
    }
  }
  
  /// Read the file for "buf" again and check if the contents changed.
  /// Return true if it changed or this could not be checked.
  ///
  /// @param  buf  buffer to check
  ///
  /// @return true if the buffer's contents have changed
  bool buf_contents_changed(buf_T *buf)
    FUNC_ATTR_NONNULL_ALL
  {
    bool differ = true;
  
    // Allocate a buffer without putting it in the buffer list.
    buf_T *newbuf = buflist_new(NULL, NULL, (linenr_T)1, BLN_DUMMY);
    if (newbuf == NULL) {
      return true;
    }
  
    // Force the 'fileencoding' and 'fileformat' to be equal.
    exarg_T ea;
    prep_exarg(&ea, buf);
  
    // set curwin/curbuf to buf and save a few things
    aco_save_T aco;
    aucmd_prepbuf(&aco, newbuf);
  
    if (ml_open(curbuf) == OK
        && readfile(buf->b_ffname, buf->b_fname,
                    (linenr_T)0, (linenr_T)0, (linenr_T)MAXLNUM,
                    &ea, READ_NEW | READ_DUMMY) == OK) {
      // compare the two files line by line
      if (buf->b_ml.ml_line_count == curbuf->b_ml.ml_line_count) {
        differ = false;
        for (linenr_T lnum = 1; lnum <= curbuf->b_ml.ml_line_count; ++lnum) {
          if (STRCMP(ml_get_buf(buf, lnum, false), ml_get(lnum)) != 0) {
            differ = true;
            break;
          }
        }
      }
    }
    xfree(ea.cmd);
  
    // restore curwin/curbuf and a few other things
    aucmd_restbuf(&aco);
  
    if (curbuf != newbuf) {  // safety check
      wipe_buffer(newbuf, false);
    }
  
    return differ;
  }
  
  /*
   * Wipe out a buffer and decrement the last buffer number if it was used for
   * this buffer.  Call this to wipe out a temp buffer that does not contain any
   * marks.
   */
  void 
  wipe_buffer (
      buf_T *buf,
      int aucmd                   /* When TRUE trigger autocommands. */
  )
  {
    if (!aucmd) {
      // Don't trigger BufDelete autocommands here.
      block_autocmds();
    }
    close_buffer(NULL, buf, DOBUF_WIPE, false);
    if (!aucmd) {
      unblock_autocmds();
    }
  }
  
  /// Creates or switches to a scratch buffer. :h special-buffers
  /// Scratch buffer is:
  ///   - buftype=nofile bufhidden=hide noswapfile
  ///   - Always considered 'nomodified'
  ///
  /// @param bufnr     Buffer to switch to, or 0 to create a new buffer.
  ///
  /// @see curbufIsChanged()
  void buf_open_scratch(handle_T bufnr, char *bufname)
  {
    (void)do_ecmd((int)bufnr, NULL, NULL, NULL, ECMD_ONE, ECMD_HIDE, NULL);
    (void)setfname(curbuf, (char_u *)bufname, NULL, true);
    set_option_value("bh", 0L, "hide", OPT_LOCAL);
    set_option_value("bt", 0L, "nofile", OPT_LOCAL);
    set_option_value("swf", 0L, NULL, OPT_LOCAL);
    RESET_BINDING(curwin);
  }
  