/* Window creation, deletion and examination for GNU Emacs.
   Does not include redisplay.
   Copyright (C) 1985 Richard M. Stallman.

This file is part of GNU Emacs.

GNU Emacs is distributed in the hope that it will be useful,
but without any warranty.  No author or distributor
accepts responsibility to anyone for the consequences of using it
or for whether it serves any particular purpose or works at all,
unless he says so in writing.

Everyone is granted permission to copy, modify and redistribute
GNU Emacs, but only under the conditions described in the
document "GNU Emacs copying permission notice".   An exact copy
of the document is supposed to have been given to you along with
GNU Emacs so that you can know how you may redistribute it all.
It should be in a file named COPYING.  Among other things, the
copyright notice and this notice must be preserved on all copies.  */


#include "config.h"
#include "lisp.h"
#include "buffer.h"
#include "window.h"
#include "commands.h"
#include "indent.h"

Lisp_Object Qwindowp;

Lisp_Object Fnext_window (), Fdelete_window (), Fselect_window ();
Lisp_Object Fshow_buffer (), Fsplit_window (), Frecenter ();

/* This is the window which displays the minibuffer.
It is always the same window.  */

Lisp_Object minibuf_window;

/* This is the window in which the terminal's cursor should
 be left when nothing is being done with it.  This must
 always be a leaf window, and its buffer is selected by
 the top level editing loop at the end of each command.  */

Lisp_Object selected_window;

/* If a window gets smaller than either of these, it is removed. */

int window_min_height;
int window_min_width;

/* Nonzero implies pop_to_buffer should create windows. */

int pop_up_windows;

/* display-buffer always splits the largest window 
 if that window is more than this high */

int split_height_threshold;

/* Number of lines of continuity in scrolling by screenfuls.  */

int next_screen_context_lines;

/* Incremented for each window created.  */

static int sequence_number;

DEFUN ("windowp", Fwindowp, Swindowp, 1, 1, 0,
  "Returns t if OBJ is a window.")
  (obj)
     Lisp_Object obj;
{
  return XTYPE (obj) == Lisp_Window ? Qt : Qnil;
}

Lisp_Object
make_window ()
{
  Lisp_Object val;
  register struct window *p;

  val = Fmake_vector (
    make_number ((sizeof (struct window) - sizeof (struct Lisp_Vector))
		 / sizeof (Lisp_Object)),
    Qnil);
  XSETTYPE (val, Lisp_Window);
  p = XWINDOW (val);
  XFASTINT (p->left) = XFASTINT (p->top)
    = XFASTINT (p->height) = XFASTINT (p->width)
      = XFASTINT (p->hscroll) = 0;
  XFASTINT (p->last_dot_x) = XFASTINT (p->last_dot_y) = 0;
  p->start = Fmake_marker ();
  p->dotm = Fmake_marker ();
  XFASTINT (p->sequence_number) = ++sequence_number;
  XFASTINT (p->use_time) = 0;
  return val;
}

DEFUN ("selected-window", Fselected_window, Sselected_window, 0, 0, 0,
  "Return the window that the cursor appears in and commands apply to.")
  ()
{
  return selected_window;
}

DEFUN ("pos-visible-in-window-p", Fpos_visible_in_window_p,
  Spos_visible_in_window_p, 0, 2, 0,
  "Return t if position POS is currently on the screen in WINDOW.\n\
Returns nil if that position is scrolled vertically out of view.\n\
POS defautls to dot; WINDOW, to the selected window.")
  (pos, window)
     Lisp_Object pos, window;
{
  register struct window *w;
  register int top;
  register int height;
  register int posint;
  register struct buffer_text *text;
  struct position posval;

  if (NULL (pos))
    posint = dot;
  else
    {
      CHECK_NUMBER_COERCE_MARKER (pos, 0);
      posint = XINT (pos);
    }

  if (NULL (window))
    window = selected_window;
  else
    CHECK_WINDOW (window, 1);
  w = XWINDOW (window);
  top = marker_position (w->start);

  if (posint < top)
    return Qnil;

  height = XFASTINT (w->height) - !EQ (window, minibuf_window);

  bf_cur->text = bf_text;
  text = &XBUFFER (w->buffer)->text;
  if (XFASTINT (w->last_modified) >= text->modified)
    {
      /* If screen is up to date,
	 use the info recorded about how much text fit on it. */
      if (posint < text->size1 + text->size2 + 1 - XFASTINT (w->window_end_pos)
	  || (XFASTINT (w->window_end_vpos) < height))
	return Qt;
      return Qnil;
    }
  else
    {
      if (posint > text->size1 + text->size2 + 1)
	return Qnil;
      /* If that info is not correct, calculate afresh */
      posval = compute_motion (top, 0, 0,
			       posint, height, 0,
			       XFASTINT (w->width) - 1
			       - (XFASTINT (w->width) + XFASTINT (w->left) != XFASTINT (XWINDOW (minibuf_window)->width)),

			       XINT (w->hscroll));
      return posval.vpos < height ? Qt : Qnil;
    }
}

struct window *
decode_window (window)
     Lisp_Object window;
{
  if (NULL (window))
    return XWINDOW (selected_window);

  CHECK_WINDOW (window, 0);
  return XWINDOW (window);
}

DEFUN ("window-buffer", Fwindow_buffer, Swindow_buffer, 0, 1, 0,
  "Return the buffer that WINDOW is displaying.")
  (window)
     Lisp_Object window;
{
  return decode_window (window)->buffer;
}

DEFUN ("window-height", Fwindow_height, Swindow_height, 0, 1, 0,
  "Return the number of lines in WINDOW (including its mode line).")
  (window)
     Lisp_Object window;
{
  return decode_window (window)->height;
}

DEFUN ("window-width", Fwindow_width, Swindow_width, 0, 1, 0,
  "Return the number of columns in WINDOW.")
  (window)
     Lisp_Object window;
{
  return decode_window (window)->width;
}

DEFUN ("window-hscroll", Fwindow_hscroll, Swindow_hscroll, 0, 1, 0,
  "Return the number of columns by which WINDOW is scrolled from left margin.")
  (window)
     Lisp_Object window;
{
  return decode_window (window)->hscroll;
}

DEFUN ("set-window-hscroll", Fset_window_hscroll, Sset_window_hscroll, 2, 2, 0,
  "Set number of columns WINDOW is scrolled from left margin to NCOL.\n\
NCOL should be zero or positive.")
  (window, ncol)
     Lisp_Object window, ncol;
{
  CHECK_NUMBER (ncol, 1);
  if (XINT (ncol) < 0) XFASTINT (ncol) = 0;
  if (XFASTINT (ncol) >= (1 << (SHORTBITS - 1)))
    Fsignal (Qargs_out_of_range, Fcons (ncol, Qnil));

  clip_changed = 1;		/* Prevent redisplay shortcuts */
  decode_window (window)->hscroll = ncol;
  return ncol;
}

DEFUN ("window-edges", Fwindow_edges, Swindow_edges, 0, 1, 0,
  "Return a list of the edge coordinates of WINDOW.\n\
\(LEFT TOP RIGHT BOTTOM), all relative to 0, 0 at top left corner of screen.")
  (window)
     Lisp_Object window;
{
  register struct window *w = decode_window (window);

  return Fcons (w->left, Fcons (w->top,
           Fcons (make_number (XFASTINT (w->left) + XFASTINT (w->width)),
		  Fcons (make_number (XFASTINT (w->top)
				      + XFASTINT (w->height)),
			 Qnil))));
}

DEFUN ("window-dot", Fwindow_dot, Swindow_dot, 0, 1, 0,
  "Return current value of dot in WINDOW.")
  (window)
     Lisp_Object window;
{
  return Fmarker_position (decode_window (window)->dotm);
}

DEFUN ("window-start", Fwindow_start, Swindow_start, 0, 1, 0,
  "Return position at which display currently starts in WINDOW.")
  (window)
     Lisp_Object window;
{
  return Fmarker_position (decode_window (window)->start);
}

DEFUN ("set-window-dot", Fset_window_dot, Sset_window_dot, 2, 2, 0,
  "Make dot value in WINDOW be at position POS in WINDOW's buffer.")
  (window, pos)
     Lisp_Object window, pos;
{
  struct window *w = decode_window (window);
  CHECK_NUMBER_COERCE_MARKER (pos, 1);
  Fset_marker (w->dotm, pos, w->buffer);
  return pos;
}

DEFUN ("set-window-start", Fset_window_start, Sset_window_start, 2, 3, 0,
  "Make display in WINDOW start at position POS in WINDOW's buffer.\n\
Optional third arg NOFORCE non-nil inhibits next redisplay\n\
from overriding motion of dot in order to display at this exact start.")
  (window, pos, noforce)
     Lisp_Object window, pos, noforce;
{
  struct window *w = decode_window (window);
  CHECK_NUMBER_COERCE_MARKER (pos, 1);
  Fset_marker (w->start, pos, w->buffer);
  if (NULL (noforce))
    w->force_start = Qt;
  w->redo_mode_line = Qt;
  XFASTINT (w->last_modified) = 0;
  return pos;
}

DEFUN ("delete-window", Fdelete_window, Sdelete_window, 0, 1, "",
  "Remove WINDOW from the display.  Default is selected window.")
  (window)
     Lisp_Object window;
{
  int osize;
  Lisp_Object tem, parent;
  register struct window *p;

  if (NULL (window))
    window = selected_window;
  else
    CHECK_WINDOW (window, 0);

  p = XWINDOW (window);
  parent = p->parent;
  if (NULL (parent))
    error ("Attempt to delete minibuffer or sole ordinary window");

  windows_or_buffers_changed++;

  if (EQ (window, selected_window))
    Fselect_window (Fnext_window (window, Qnil));

  if (!NULL (p->buffer))
    unshow_buffer (p);

  unchain_marker (p->dotm);
  unchain_marker (p->start);

  tem = p->next;
  if (!NULL (tem))
    XWINDOW (tem)->prev = p->prev;

  tem = p->prev;
  if (!NULL (tem))
    XWINDOW (tem)->next = p->next;

  if (EQ (window, XWINDOW (parent)->hchild))
    XWINDOW (parent)->hchild = p->next;
  if (EQ (window, XWINDOW (parent)->vchild))
    XWINDOW (parent)->vchild = p->next;

  /* Stretch the siblings to use all the available space */
  if (!NULL (XWINDOW (parent)->vchild))
    {
      /* It's a vertical combination */
      osize = XFASTINT (XWINDOW (parent)->height);
      XFASTINT (XWINDOW (parent)->height)
	-= XFASTINT (p->height);
      set_window_height (parent, osize, 0);
    }
  if (!NULL (XWINDOW (parent)->hchild))
    {
      /* It's a horizontal combination */
      osize = XFASTINT (XWINDOW (parent)->width);
      XFASTINT (XWINDOW (parent)->width)
	-= XFASTINT (p->width);
      set_window_width (parent, osize, 0);
    }

  /* If parent now has only one child,
     put the child into the parent's place.  */

  tem = XWINDOW (parent)->hchild;
  if (NULL (tem))
    tem = XWINDOW (parent)->vchild;
  if (NULL (XWINDOW (tem)->next))
    replace_window (parent, tem);
  return Qnil;
}

/* Put replacement into the window structure in place of old. */

replace_window (old, replacement)
     Lisp_Object old, replacement;
{
  Lisp_Object tem;
  register struct window *o = XWINDOW (old), *p = XWINDOW (replacement);

  p->left = o->left;
  p->top = o->top;
  p->width = o->width;
  p->height = o->height;

  p->next = tem = o->next;
  if (!NULL (tem))
    XWINDOW (tem)->prev = replacement;

  p->prev = tem = o->prev;
  if (!NULL (tem))
    XWINDOW (tem)->next = replacement;

  p->parent = tem = o->parent;
  if (!NULL (tem))
    {
      if (EQ (XWINDOW (tem)->vchild, old))
	XWINDOW (tem)->vchild = replacement;
      if (EQ (XWINDOW (tem)->hchild, old))
	XWINDOW (tem)->hchild = replacement;
    }

/*** Here, if replacement is a vertical combination
and so is its new parent, we should make replacement's
children be children of that parent instead.  ***/
}

DEFUN ("next-window", Fnext_window, Snext_window, 0, 2, 0,
  "Return next window after WINDOW in canonical ordering of windows.")
  (window, yesmini)
     Lisp_Object window, yesmini;
{
  Lisp_Object tem;
  if (NULL (window))
    window = selected_window;
  else
    CHECK_WINDOW (window, 0);
  do
    {
      while (tem = XWINDOW (window)->next, NULL (tem))
	if (tem = XWINDOW (window)->parent, !NULL (tem))
	  window = tem;
        else  /* window must be minibuf_window now */
	  {
	    tem = XWINDOW (window)->prev;
	    break;
	  }
      window = tem;
      while (1)
	{
	  if (!NULL (XWINDOW (window)->hchild))
	    window = XWINDOW (window)->hchild;
	  else if (!NULL (XWINDOW (window)->vchild))
	    window = XWINDOW (window)->vchild;
	  else break;
	}
    }
  while (EQ (window, minibuf_window) && NULL (yesmini) && !MinibufDepth);
  return window;
}

DEFUN ("previous-window", Fprevious_window, Sprevious_window, 0, 1, 0,
  "Return previous window before WINDOW in canonical ordering of windows.")
  (window)
     Lisp_Object window;
{
  Lisp_Object tem;
  if (NULL (window))
    window = selected_window;
  else
    CHECK_WINDOW (window, 0);
  do  /* at least once, and until not the minibuffer */
    {
      while (tem = XWINDOW (window)->prev, NULL (tem))
	if (tem = XWINDOW (window)->parent, !NULL (tem))
	  window = tem;
        else  /* window must be the root window now */
	  {
	    tem = minibuf_window;
	    break;
	  }
      window = tem;
      while (1)
	{
	  if (!NULL (XWINDOW (window)->hchild))
	    window = XWINDOW (window)->hchild;
	  else if (!NULL (XWINDOW (window)->vchild))
	    window = XWINDOW (window)->vchild;
	  else break;
	  while (tem = XWINDOW (window)->next, !NULL (tem))
	    window = tem;
	}
    }
  while (EQ (window, minibuf_window) && !MinibufDepth);
  return window;
}

DEFUN ("other-window", Fother_window, Sother_window, 1, 1, "p",
  "Select the ARG'th different window.")
  (n)
     Lisp_Object n;
{
  int i;
  Lisp_Object w;

  CHECK_NUMBER (n, 0);
  w = selected_window;
  i = XINT (n);

  while (i > 0)
    {
      w = Fnext_window (w, Qnil);
      i--;
    }
  while (i < 0)
    {
      w = Fprevious_window (w);
      i++;
    }
  Fselect_window (w);
  return Qnil;
}

Lisp_Object
window_loop (type, obj)
     int type;
     Lisp_Object obj;
{
  Lisp_Object w, w1, ret_w, tem;
  register struct window *p, *q;

  w = minibuf_window;
  ret_w = Qnil;
  while (1)
    {
      p = XWINDOW (w);
      w1 = Fnext_window (w, Qt);
      if (!EQ (w, minibuf_window))
	switch (type)
	  {
	  case 1:
	    if (XBUFFER (p->buffer) == XBUFFER (obj))
	      return w;
	    break;

	  case 2:
	    if (NULL (ret_w) ||
		XFASTINT (XWINDOW (ret_w)->use_time) > XFASTINT (p->use_time))
	      ret_w = w;
	    break;

	  case 3:
	    if (p != XWINDOW (obj))
	      Fdelete_window (w);
	    break;

	  case 4:
	    if (EQ (p->buffer, obj))
	      {
		if (NULL (p->parent))
		  {
		    tem = Fother_buffer (obj);
		    if (NULL (tem))
		      tem = Fget_buffer_create (build_string ("*scratch*"));
		    Fshow_buffer (w, tem);
		    Fset_buffer (p->buffer);
		  }
		else
		  Fdelete_window (w);
	      }
	    break;

	  case 5:
	    q = XWINDOW (ret_w);
	    if (NULL (ret_w) ||
		(XFASTINT (p->height) * XFASTINT (p->width))
		>
		(XFASTINT (q->height) * XFASTINT (q->width)))
	      ret_w = w;
	    break;

	  case 6:
	    if (EQ (p->buffer, obj))
	      {
		tem = Fother_buffer (obj);
		if (NULL (tem))
		  tem = Fget_buffer_create (build_string ("*scratch*"));
		Fshow_buffer (w, tem);
		Fset_buffer (p->buffer);
	      }
	    break;
	  }
      w = w1;
      if (EQ (w, minibuf_window))
	return ret_w;
    }
}     

DEFUN ("get-lru-window", Fget_lru_window, Sget_lru_window, 0, 0, 0,
  "Return the window least recently selected or used for display.")
  ()
{
  return window_loop (2, Qnil);
}

DEFUN ("get-largest-window", Fget_largest_window, Sget_largest_window, 0, 0, 0,
  "Return the largest window in area.")
  ()
{
  return window_loop (5, Qnil);
}

DEFUN ("get-buffer-window", Fget_buffer_window, Sget_buffer_window, 1, 1, 0,
  "Return a window currently displaying BUFFER, or nil if none.")
  (buffer)
     Lisp_Object buffer;
{
  buffer = Fget_buffer (buffer);
  if (XTYPE (buffer) == Lisp_Buffer)
    return window_loop (1, buffer);
  else return Qnil;
}

DEFUN ("delete-other-windows", Fdelete_other_windows, Sdelete_other_windows,
  0, 1, "",
  "Make WINDOW (or the selected window) fill the screen.")
  (w)
     Lisp_Object w;
{
  window_loop (3, !NULL (w) ? w : selected_window);
  return Qnil;
}

DEFUN ("delete-windows-on", Fdelete_windows_on, Sdelete_windows_on,
  1, 1, "bDelete windows on (buffer): ",
  "Delete all windows showing BUFFER.")
  (buffer)
     Lisp_Object buffer;
{
  if (!NULL (buffer))
    {
      buffer = Fget_buffer (buffer);
      CHECK_BUFFER (buffer, 0);
      window_loop (4, buffer);
    }
  return Qnil;
}

DEFUN ("replace-buffer-in-windows", Freplace_buffer_in_windows,
  Sreplace_buffer_in_windows,
  1, 1, "bReplace buffer in windows: ",
  "Replace BUFFER with some other buffer in all windows showing it.")
  (buffer)
     Lisp_Object buffer;
{
  if (!NULL (buffer))
    {
      buffer = Fget_buffer (buffer);
      CHECK_BUFFER (buffer, 0);
      window_loop (6, buffer);
    }
  return Qnil;
}

/* Set the height of WINDOW and all its inferiors.  */
/* Normally the window is deleted if it gets too small.
   nodelete nonzero means do not do this.
   (The caller should check later and do so if appropriate)  */

set_window_height (window, height, nodelete)
     Lisp_Object window;
     int height;
     int nodelete;
{
  register struct window *w = XWINDOW (window);
  register struct window *c;
  int oheight = XFASTINT (w->height);
  int top, pos, lastbot, opos, lastobot;
  Lisp_Object tem, child;

  if (window_min_height < 2)
    window_min_height = 2;

  if (!nodelete &&
      height < (EQ(window, minibuf_window) ? 1 : window_min_height))
    {
      Fdelete_window (window);
      return;
    }

  XFASTINT (w->last_modified) = 0;
  windows_or_buffers_changed++;
  XFASTINT (w->height) = height;
  if (!NULL (w->hchild))
    {
      for (child = w->hchild; !NULL (child); child = XWINDOW (child)->next)
	{
	  XWINDOW (child)->top = w->top;
	  set_window_height (child, height, 0);
	}
    }
  else if (!NULL (w->vchild))
    {
      lastbot = top = XFASTINT (w->top);
      lastobot = 0;
      for (child = w->vchild; !NULL (child);)
	{
	  c = XWINDOW (child);

	  opos = lastobot + XFASTINT (c->height);

	  XFASTINT (c->top) = lastbot;

	  pos = (((opos * height) << 1) + oheight) / (oheight << 1);

	  /* Avoid confusion: inhibit deletion of child if becomes too small */
	  set_window_height (child, pos + top - lastbot, 1);

	  /* Now advance child to next window,
	     and set lastbot if child was not just deleted.  */
	  child = c->next;
	  lastbot = pos + top, lastobot = opos;
	}
      /* Now delete any children that became too small.  */
      for (child = w->vchild; !NULL (child); child = XWINDOW (child)->next)
	{
	  set_window_height (child, XFASTINT (XWINDOW (child)->height), 0);
	}
    }
}

/* Recursively set width of WINDOW and its inferiors. */

set_window_width (window, width, nodelete)
     Lisp_Object window;
     int width;
     int nodelete;
{
  register struct window *w = XWINDOW (window);
  register struct window *c;
  int owidth = XFASTINT (w->width);
  int left, pos, lastright, opos, lastoright;
  Lisp_Object tem, child;

  if (!nodelete && width < window_min_width)
    {
      Fdelete_window (window);
      return;
    }

  XFASTINT (w->last_modified) = 0;
  XFASTINT (w->width) = width;
  if (!NULL (w->vchild))
    {
      for (child = w->vchild; !NULL (child); child = XWINDOW (child)->next)
	{
	  XWINDOW (child)->left = w->left;
	  set_window_width (child, width, 0);
	}
    }
  else if (!NULL (w->hchild))
    {
      lastright = left = XFASTINT (w->left);
      lastoright = 0;
      for (child = w->hchild; !NULL (child);)
	{
	  c = XWINDOW (child);

	  opos = lastoright + XFASTINT (c->width);

	  XFASTINT (c->left) = lastright;

	  pos = (((opos * width) << 1) + owidth) / (owidth << 1);

	  /* Inhibit deletion for becoming too small */
	  set_window_width (child, pos + left - lastright, 1);

	  /* Now advance child to next window,
	     and set lastright if child was not just deleted.  */
	  child = c->next;
	  lastright = pos + left, lastoright = opos;
	}
      /* Delete children that became too small */
      for (child = w->hchild; !NULL (child); child = XWINDOW (child)->next)
	{
	  set_window_width (child, XFASTINT (XWINDOW (child)->width), 0);
	}
    }
}

static int window_select_count;

DEFUN ("show-buffer", Fshow_buffer, Sshow_buffer, 2, 2, 0,
  "Make WINDOW display BUFFER as its contents.\n\
BUFFER can be a buffer or buffer name.")
  (window, buffer)
     Lisp_Object window, buffer;
{
  Lisp_Object tem;
  struct window *w = decode_window (window);

  buffer = Fget_buffer (buffer);
  CHECK_BUFFER (buffer, 1);

  if (NULL (XBUFFER (buffer)->name))
    error ("Attempt to display deleted buffer");

  tem = w->buffer;
  if (!NULL (tem))
    unshow_buffer (w, tem);

  w->buffer = buffer;
  Fset_marker (w->dotm,
	       make_number (XBUFFER (buffer) == bf_cur
			    ? dot : XBUFFER (buffer)->text.dotloc),
	       buffer);
  Fset_marker (w->start, make_number (XBUFFER (buffer)->last_window_start),
	       buffer);
  XFASTINT (w->last_modified) = 0;
  windows_or_buffers_changed++;
  if (EQ (window, selected_window))
    Fset_buffer (buffer);

  return Qnil;
}

/* Record info on buffer window w is displaying
 when it is about to cease to display that buffer.  */

unshow_buffer (w)
     struct window *w;
{
  Lisp_Object buf;
  buf = w->buffer;

  if (XBUFFER (buf) != XMARKER (w->dotm)->buffer)
    abort ();

  if (w != XWINDOW (selected_window)
      && EQ (buf, XWINDOW (selected_window)->buffer))
    return;

  if (XBUFFER (buf) == bf_cur)
    {
      if (w != XWINDOW (selected_window))
	dot = marker_position (w->dotm);
    }
  else
    XBUFFER (buf)->text.dotloc = 
      marker_position (w->dotm);
  XBUFFER (buf)->last_window_start = 
    marker_position (w->start);
}

DEFUN ("select-window", Fselect_window, Sselect_window, 1, 1, 0,
  "Select WINDOW.  Most editing will apply to WINDOW's buffer.\n\
The main editor command loop selects the buffer of the selected window\n\
before each command.")
  (window)
     Lisp_Object window;
{
  register struct window *w = XWINDOW (window);
  register struct window *ow = XWINDOW (selected_window);
  register int newdot;

  CHECK_WINDOW (window, 0);

  if (NULL (w->buffer))
    error ("Trying to select window with no buffer");

  XFASTINT (w->use_time) = ++window_select_count;
  if (EQ (window, selected_window))
    return window;

  if (bf_cur == XBUFFER (ow->buffer))
    Fset_marker (ow->dotm, make_number (dot), ow->buffer);

  selected_window = window;

  record_buffer (w->buffer);
  Fset_buffer (w->buffer);
  if (bf_cur == XBUFFER (ow->buffer))
    SetDot (marker_position (w->dotm));

  windows_or_buffers_changed++;

  return window;
}

DEFUN ("display-buffer", Fdisplay_buffer, Sdisplay_buffer, 1, 1, 0,
  "Make BUFFER appear in some window but don't select them.\n\
BUFFER can be a buffer or a buffer name.\n\
Returns the window displaying BUFFER.")
  (buffer)
     Lisp_Object buffer;
{
  Lisp_Object window;
  buffer = Fget_buffer (buffer);
  CHECK_BUFFER (buffer, 0);

  if (XBUFFER (XWINDOW (selected_window)->buffer) == XBUFFER (buffer))
    return selected_window;

  window = Fget_buffer_window (buffer);
  if (!NULL (window))
    return window;

  if (pop_up_windows)
    {
      /* Don't try to create a window if would get an error */
      if (window_min_height < 2)
	window_min_height = 2;
      if (split_height_threshold < window_min_height << 1)
	split_height_threshold = window_min_height << 1;

      window = Fget_largest_window ();
      if (window_height (window) >= split_height_threshold)
	window = Fsplit_window (window, Qnil, Qnil);
      else
	{
	  window = Fget_lru_window ();
	  if ((EQ (window, selected_window)
	       || (EQ (selected_window, minibuf_window)
		   && EQ (window, XWINDOW (minibuf_window)->prev)))
	      && window_height (window) >= window_min_height << 1)
	    window = Fsplit_window (window, Qnil, Qnil);
	}
    }
  else
    window = Fget_lru_window ();

  Fshow_buffer (window, buffer);
  return window;
}

temp_output_buffer_show (buf)
     Lisp_Object buf;
{
  struct buffer *old = bf_cur;
  Lisp_Object window;

  Fset_buffer (buf);
  XBUFFER (buf)->save_modified = bf_modified;
  SetDot (1);
  bf_head_clip = 1;
  bf_tail_clip = 0;
  clip_changed = 1;
  SetBfp (old);

  window = Fdisplay_buffer (buf);
  XFASTINT (XWINDOW (window)->hscroll) = 0;
  Fset_marker (XWINDOW (window)->start, make_number (1), buf);
  Fset_marker (XWINDOW (window)->dotm, make_number (1), buf);
}

make_dummy_parent (window)
     Lisp_Object window;
{
  Lisp_Object old, new;
  register struct window *o, *p;
  old = window;
  XSETTYPE (old, Lisp_Vector);
  new = Fcopy_sequence (old);
  XSETTYPE (new, Lisp_Window);

  o = XWINDOW (old);
  p = XWINDOW (new);
  XFASTINT (p->sequence_number) = ++sequence_number;

  /* Put new into window structure in place of window */
  replace_window (window, new);

  o->next = Qnil;
  o->prev = Qnil;
  o->vchild = Qnil;
  o->hchild = Qnil;
  o->parent = new;

  p->start = Qnil;
  p->dotm = Qnil;
  p->buffer = Qnil;
}

DEFUN ("split-window", Fsplit_window, Ssplit_window, 0, 3, "",
  "Split WINDOW, putting SIZE lines in the first of the pair.\n\
WINDOW defaults to selected one and SIZE to half its size.\n\
If optional third arg HOR-FLAG is non-nil, split side by side\n\
and put SIZE columns in the first of the pair.")
  (window, chsize, horflag)
     Lisp_Object window, chsize, horflag;
{
  Lisp_Object new;
  register struct window *o, *p, *w;
  int size;

  if (NULL (window))
    window = selected_window;
  else
    CHECK_WINDOW (window, 0);

  o = XWINDOW (window);

  if (NULL (chsize))
    {
      if (!NULL (horflag))
	size = XFASTINT (o->width) >> 1;
      else
	size = XFASTINT (o->height) >> 1;
    }
  else
    {
      CHECK_NUMBER (chsize, 1);
      size = XINT (chsize);
    }

  if (EQ (window, minibuf_window))
    error ("Attempt to split minibuffer window");

  if (NULL (horflag))
    {
      if (window_min_height < 2)
	window_min_height = 2;

      if (size < window_min_height ||
	  size + window_min_height > XFASTINT (o->height))
	Fsignal (Qargs_out_of_range, Flist (3, &window));
      if (NULL (o->parent) ||
	  NULL (XWINDOW (o->parent)->vchild))
	{
	  make_dummy_parent (window);
	  new = o->parent;
	  XWINDOW (new)->vchild = window;
	}
    }
  else
    {
      if (size < window_min_width ||
	  size + window_min_width > XFASTINT (o->width))
	Fsignal (Qargs_out_of_range, Flist (3, &window));
      if (NULL (o->parent) ||
	  NULL (XWINDOW (o->parent)->hchild))
	{
	  make_dummy_parent (window);
	  new = o->parent;
	  XWINDOW (new)->hchild = window;
	}
    }

  /* Now we know that window's parent is a vertical combination
     if we are dividing vertically, or a horizontal combination
     if we are making side-by-side windows */

  windows_or_buffers_changed++;
  new = make_window ();
  p = XWINDOW (new);

  p->next = o->next;
  if (!NULL (p->next))
    XWINDOW (p->next)->prev = new;
  p->prev = window;
  o->next = new;
  p->parent = o->parent;

  Fshow_buffer (new, o->buffer);

  /* Apportion the available screen space among the two new windows */

  if (!NULL (horflag))
    {
      p->height = o->height;
      p->top = o->top;
      XFASTINT (p->width) = XFASTINT (o->width) - size;
      XFASTINT (o->width) = size;
      XFASTINT (p->left) = XFASTINT (o->left) + size;
    }
  else
    {
      p->left = o->left;
      p->width = o->width;
      XFASTINT (p->height) = XFASTINT (o->height) - size;
      XFASTINT (o->height) = size;
      XFASTINT (p->top) = XFASTINT (o->top) + size;
    }

  return new;
}

DEFUN ("enlarge-window", Fenlarge_window, Senlarge_window, 1, 2, "p",
  "Make current window ARG lines bigger.\n\
From program, optional second arg non-nil means grow sideways ARG columns.")
  (n, side)
     Lisp_Object n, side;
{
  CHECK_NUMBER (n, 0);
  change_window_height (XINT (n), !NULL (side));
  return Qnil;
}

DEFUN ("shrink-window", Fshrink_window, Sshrink_window, 1, 2, "p",
  "Make current window ARG lines smaller.\n\
From program, optional second arg non-nil means shrink sideways ARG columns.")
  (n, side)
     Lisp_Object n, side;
{
  CHECK_NUMBER (n, 0);
  change_window_height (-XINT (n), !NULL (side));
  return Qnil;
}

int
window_height (window)
     Lisp_Object window;
{
  register struct window *p = XWINDOW (window);
  return XFASTINT (p->height);
}

int
window_width (window)
     Lisp_Object window;
{
  register struct window *p = XWINDOW (window);
  return XFASTINT (p->width);
}

#define MINSIZE(window) \
  (widthflag ? window_min_width  \
   : (EQ (window, minibuf_window) ? 1 : window_min_height))

#define CURBEG(w) \
  *(widthflag ? (int *) &w->left : (int *) &w->top)

#define CURSIZE(w) \
  *(widthflag ? (int *) &w->width : (int *) &w->height)

/* Unlike set_window_height, this function
 also changes the heights of the siblings so as to
 keep everything consistent. */

change_window_height (delta, widthflag)
     int delta, widthflag;
{
  Lisp_Object window, parent, tem;
  register struct window *p;
  int *sizep;
  int *startp;
  int (*sizefun) () = widthflag ? window_width : window_height;
  int (*setsizefun) () = widthflag ? set_window_width : set_window_height;
  int opht, maxdelta;

  window = selected_window;
  while (1)
    {
      p = XWINDOW (window);
      parent = p->parent;
      if (NULL (parent))
	{
	  if (widthflag)
	    error ("No other window to side of this one");
	  break;
	}
      if (widthflag ? !NULL (XWINDOW (parent)->hchild)
	  : !NULL (XWINDOW (parent)->vchild))
	break;
      window = parent;
    }

  sizep = &CURSIZE (p);
  startp = &CURBEG (p);

  if (*sizep + delta < MINSIZE (window))
    {
      Fdelete_window (window);
      return;
    }

  maxdelta = (!NULL (parent) ? sizefun (parent) - *sizep
	      : (tem = (!NULL (p->next) ? p->next : p->prev),
		 sizefun (tem) - MINSIZE (tem)));

  if (delta > maxdelta)
    /* This case traps trying to make the minibuffer
       the full screen, or make the only window aside from the
       minibuffer the full screen.  */
    delta = maxdelta;

  if (!NULL (p->next) &&
      sizefun (p->next) - delta >= MINSIZE (p->next))
    {
      setsizefun (p->next, sizefun (p->next) - delta, 0);
      setsizefun (window, *sizep + delta, 0);
      CURBEG (XWINDOW (p->next)) += delta;
      /* This does not change size of p->next,
	 but it propagates the new top edge to its children */
      setsizefun (p->next, sizefun (p->next), 0);
    }
  else if (!NULL (p->prev) &&
	   sizefun (p->prev) - delta >= MINSIZE (p->prev))
    {
      setsizefun (p->prev, sizefun (p->prev) - delta, 0);
      CURBEG (p) -= delta;
      setsizefun (window, *sizep + delta, 0);
    }
  else
    {
      opht = sizefun (parent);

      delta = (int) ((float) (delta * opht)
		     / (float) (opht - *sizep - delta));
      /* Add delta lines or columns to this window, and to the parent,
	 keeping things consistent while not affecting siblings.  */
      CURSIZE (XWINDOW (parent)) = opht + delta;
      setsizefun (window, *sizep + delta, 0);
      /* Squeeze out delta lines or columns from our parent,
	 shriking this window and siblings proportionately.
	 This brings parent back to correct size.
	 Delta was calculated so this makes this window the desired size,
	 taking it all out of the siblings.  */
      setsizefun (parent, opht, 0);
    }

  XFASTINT (p->last_modified) = 0;
}

static
window_scroll (window, n)
     Lisp_Object window;
     int n;
{
  register struct window *w = XWINDOW (window);
  register int odot = dot;
  register int ht, pos;
  Lisp_Object tem;

  ht = XFASTINT (w->height) - !EQ (window, minibuf_window);

  XFASTINT (tem) = dot;
  tem = Fpos_visible_in_window_p (tem, window);

  if (NULL (tem))
    {
      Fvertical_motion (make_number (- ht / 2));
      XFASTINT (tem) = dot;
      Fset_marker (w->start, tem, w->buffer);
      w->force_start = Qt;
    }

  SetDot (marker_position (w->start));
  Fvertical_motion (make_number (n));
  pos = dot;
  SetDot (odot);

  if (pos < NumCharacters + 1)
    {
      Fset_marker (w->start, make_number (pos), w->buffer);
      w->redo_mode_line = Qt;
      XFASTINT (w->last_modified) = 0;
      if (pos > odot)
	SetDot (pos);
      if (n < 0)
	{
	  SetDot (pos);
	  tem = Fvertical_motion (make_number (ht));
	  if (dot > odot || XFASTINT (tem) < ht)
	    SetDot (odot);
	  else
	    Fvertical_motion (make_number (-1));
	}
    }
  else
    Fsignal (Qend_of_buffer, Qnil);
}

DEFUN ("scroll-up", Fscroll_up, Sscroll_up, 0, 1, "P",
  "Scroll text of current window upward ARG lines; or near full screen if no ARG.\n\
When calling from a program, supply a number as argument or nil.")
  (n)
     Lisp_Object n;
{
  register int ht = window_height (selected_window) - 1;

  if (NULL (n))
    window_scroll (selected_window, ht - next_screen_context_lines);
  else if (EQ (n, Qminus))
    window_scroll (selected_window, next_screen_context_lines - ht);
  else
    {
      if (XTYPE (n) == Lisp_Cons)
	n = Fcar (n);
      CHECK_NUMBER (n, 0);
      window_scroll (selected_window, XINT (n), 0);
    }
  return Qnil;
}

DEFUN ("scroll-down", Fscroll_down, Sscroll_down, 0, 1, "P",
  "Scroll text of current window downward ARG lines; or near full screen if no ARG.\n\
When calling from a program, supply a number as argument or nil.")
  (n)
     Lisp_Object n;
{
  register int ht = window_height (selected_window) - 1;

  if (NULL (n))
    window_scroll (selected_window, next_screen_context_lines - ht);
  else if (EQ (n, Qminus))
    window_scroll (selected_window, ht - next_screen_context_lines);
  else
    {
      if (XTYPE (n) == Lisp_Cons)
	n = Fcar (n);
      CHECK_NUMBER (n, 0);
      window_scroll (selected_window, -XINT (n));
    }
  return Qnil;
}

DEFUN ("scroll-left", Fscroll_left, Sscroll_left, 1, 1, "p",
  "Scroll selected window display ARG columns left.")
  (arg)
     Lisp_Object arg;
{
  CHECK_NUMBER (arg, 0);
  return Fset_window_hscroll (selected_window,
			      make_number (XINT (XWINDOW (selected_window)->hscroll)
					   + XINT (arg)));
}

DEFUN ("scroll-right", Fscroll_right, Sscroll_right, 1, 1, "p",
  "Scroll selected window display ARG columns right.")
  (arg)
     Lisp_Object arg;
{
  CHECK_NUMBER (arg, 0);
  return Fset_window_hscroll (selected_window,
			      make_number (XINT (XWINDOW (selected_window)->hscroll)
					   - XINT (arg)));
}

DEFUN ("scroll-other-window", Fscroll_other_window, Sscroll_other_window, 0, 1, "P",
  "Scroll text of next window upward ARG lines; or near full screen if no ARG.\n\
The next window is the one below the current one; or the one at the top\n\
if the current one is at the bottom.\n\
When calling from a program, supply a number as argument or nil.")
  (n)
     Lisp_Object n;
{
  Lisp_Object window;
  struct buffer *old = bf_cur;
  register int ht;
  register int odot = dot;

  window = Fnext_window (selected_window, Qnil);
  ht = window_height (window) - 1;

  if (EQ (window, selected_window))
    error ("There is no other window");

  Fset_buffer (XWINDOW (window)->buffer);
  SetDot (marker_position (XWINDOW (window)->dotm));

  if (NULL (n))
    window_scroll (window, ht - next_screen_context_lines);
  else if (EQ (n, Qminus))
    window_scroll (window, next_screen_context_lines - ht);
  else
    {
      if (XTYPE (n) == Lisp_Cons)
	n = Fcar (n);
      CHECK_NUMBER (n, 0);
      window_scroll (window, XINT (n));
    }

  Fset_marker (XWINDOW (window)->dotm, make_number (dot), Qnil);
  SetBfp (old);
  SetDot (odot);
  return Qnil;
}

DEFUN ("recenter", Frecenter, Srecenter, 0, 1, "P",
  "Center dot in window and redisplay screen.  With ARG, put dot on line ARG.\n\
The desired position of dot is always relative to the current window.\n\
If there is no ARG (i.e., it is nil) then the entire screen is redisplayed.")
  (n)
     Lisp_Object n;
{
  int ht = window_height (selected_window)
	    - !EQ (selected_window, minibuf_window);
  struct window *w = XWINDOW (selected_window);
  register int odot = dot;

  if (NULL (n))
    {
      extern int screen_garbaged;
      screen_garbaged++;
      XFASTINT (n) = ht / 2;
    }
  else
    {
      n = Fprefix_numeric_value (n);
      CHECK_NUMBER (n, 0);
    }

  if (XINT (n) < 0)
    XSETINT (n, XINT (n) + ht);

  XSETINT (n, - XINT (n));

  Fvertical_motion (n);
  Fset_marker (w->start, make_number (dot), w->buffer);

  SetDot (odot);
  w->force_start = Qt;

  return Qnil;
}

DEFUN ("move-to-window-line", Fmove_to_window_line, Smove_to_window_line,
  1, 1, "P",
  "Position dot relative to window.\n\
With no argument, position at text at center of window.\n\
An argument specifies screen line; zero means top of window,\n\
negative means relative to bottom of window.")
  (arg)
     Lisp_Object arg;
{
  int height = XFASTINT (XWINDOW (selected_window)->height);

  if (!EQ (selected_window, minibuf_window)) height--;

  if (NULL (arg))
    XFASTINT (arg) = height / 2;
  else
    {
      arg = Fprefix_numeric_value (arg);
      if (XINT (arg) < 0)
	XSETINT (arg, XINT (arg) + height);
    }

  SetDot (marker_position (XWINDOW (selected_window)->start));
  return Fvertical_motion (arg);
}

struct saved_window
  {
    Lisp_Object window;
    Lisp_Object buffer, start, dotm, mark;
    Lisp_Object left, top, width, height, hscroll;
    Lisp_Object parent, prev;
  };

struct save_window_data
  {
    long size;
    struct Lisp_Vector *unused;
    Lisp_Object nsaved;
    Lisp_Object current_window;
    Lisp_Object current_buffer;
    struct saved_window info[1];
  };

save_window_restore (arg)
     Lisp_Object arg;
{
  register struct window *w;
  register struct save_window_data *data = (struct save_window_data *) XINTPTR (arg);
  register struct saved_window *p = data->info;
  Lisp_Object tem;
  register int k;

  windows_or_buffers_changed++;
  for (k = 0; k < XFASTINT (data->nsaved); k++, p++)
    {
      w = XWINDOW (p->window);
      w->next = Qnil;

      if (!NULL (p->parent))
	w->parent = data->info[XFASTINT (p->parent)].window;
      else
	w->parent = Qnil;

      if (!NULL (p->prev))
	w->prev = data->info[XFASTINT (p->prev)].window,
        XWINDOW (w->prev)->next = p->window;
      else
	{
	  w->prev = Qnil;
	  if (!NULL (w->parent))
	    {
	      if (EQ (p->width, XWINDOW (w->parent)->width))
		XWINDOW (w->parent)->vchild = p->window,
		XWINDOW (w->parent)->hchild = Qnil;
	      else
		XWINDOW (w->parent)->hchild = p->window,
		XWINDOW (w->parent)->vchild = Qnil;
	    }
	}
      w->buffer = p->buffer;
      w->left = p->left;
      w->top = p->top;
      w->width = p->width;
      w->height = p->height;
      w->hscroll = p->hscroll;
      XFASTINT (w->last_modified) = 0;

      /* Position first line in window */
      if (!NULL (w->buffer))
	{
	  if (NULL (XBUFFER (w->buffer)->name))
	    {
	      /* Buffer is dead!  Use a live buffer.  */
	      w->buffer = Fother_buffer (Qnil);
	    }
	  Fset_marker (w->start, Fmarker_position (p->start), w->buffer);
	  unchain_marker (p->start);
	  Fset_marker (w->dotm, Fmarker_position (p->dotm), w->buffer);
	  unchain_marker (p->dotm);
	}

      tem = p->mark;
      if (NULL (tem))
	XBUFFER (w->buffer)->mark = Qnil;
      else
	{
	  if (NULL (XBUFFER (w->buffer)->mark))
	    XBUFFER (w->buffer)->mark = Fmake_marker ();

	  Fset_marker (XBUFFER (w->buffer)->mark,
		       Fmarker_position (p->mark), w->buffer);
	  unchain_marker (p->mark);
	}
    }

  Fselect_window (data->current_window);
  Fset_buffer (data->current_buffer);

  free (data);
}

count_windows (window)
     struct window *window;
{
  int count = 1;
  if (!NULL (window->next))
    count += count_windows (XWINDOW (window->next));
  if (!NULL (window->vchild))
    count += count_windows (XWINDOW (window->vchild));
  if (!NULL (window->hchild))
    count += count_windows (XWINDOW (window->hchild));
  return count;
}

#define SAVE_DATA_SIZE(n_windows) \
  ((n_windows - 1) * sizeof (struct saved_window) \
   + sizeof (struct save_window_data))

Lisp_Object
save_window_save ()
{
  Lisp_Object root;
  int n_windows;
  struct save_window_data *data;
  Lisp_Object tem;
  int size;

  root = XWINDOW (minibuf_window)->prev;
  n_windows = count_windows (XWINDOW (root));

  size = SAVE_DATA_SIZE (n_windows);
  data = (struct save_window_data *) malloc (size);

  data->size = (size - sizeof (long) - sizeof (struct Lisp_Vector *))
    / sizeof (Lisp_Object);
  XFASTINT (data->nsaved) = n_windows;
  data->current_window = selected_window;
  XSETTYPE (data->current_buffer, Lisp_Buffer);
  XSETBUFFER (data->current_buffer, bf_cur);

  save_window_save_1 (root, data, 0);

  XSETTYPE (tem, Lisp_Temp_Vector), XSETINTPTR (tem, data);
  return tem;
}

save_window_save_1 (window, data, i)
     Lisp_Object window;
     struct save_window_data *data;
     int i;
{
  struct saved_window *p;
  struct window *w;
  Lisp_Object tem;

  for (;!NULL (window); window = w->next)
    {
      p = &data->info[i];
      w = XWINDOW (window);

      XFASTINT (w->temslot) = i++;
      p->window = window;
      p->buffer = w->buffer;
      p->left = w->left;
      p->top = w->top;
      p->width = w->width;
      p->height = w->height;
      p->hscroll = w->hscroll;
      if (!NULL (w->buffer))
	{
	  if (EQ (window, selected_window)
	      && XBUFFER (w->buffer) == bf_cur)
	    p->dotm = Fdot_marker ();
	  else
	    p->dotm = Fcopy_marker (w->dotm);

	  p->start = Fcopy_marker (w->start);

	  tem = XBUFFER (w->buffer)->mark;
	  if (!NULL (tem))
	    p->mark = Fcopy_marker (tem);
	  else
	    p->mark = Qnil;
	}
      else
	{
	  p->dotm = Qnil;
	  p->start = Qnil;
	  p->mark = Qnil;
	}

      if (NULL (w->parent))
	p->parent = Qnil;
      else
	p->parent = XWINDOW (w->parent)->temslot;

      if (NULL (w->prev))
	p->prev = Qnil;
      else
	p->prev = XWINDOW (w->prev)->temslot;

      if (!NULL (w->vchild))
	i = save_window_save_1 (w->vchild, data, i);
      if (!NULL (w->hchild))
	i = save_window_save_1 (w->hchild, data, i);
    }

  return i;
}

DEFUN ("save-window-excursion", Fsave_window_excursion, Ssave_window_excursion,
  0, UNEVALLED, 0,
  "Execute body, preserving window sizes and contents.\n\
Restores which buffer appears in which window, where display starts,\n\
as well as dot and mark.")
  (args)
     Lisp_Object args;
{
  Lisp_Object tem, val;
  struct gcpro gcpro1;
  int count = specpdl_ptr - specpdl;

  tem = save_window_save ();

  GCPRO1 (*XOBJFWD (tem));
  gcpro1.nvars
    = SAVE_DATA_SIZE (XFASTINT (((struct save_window_data *) XINTPTR (tem))
				->nsaved))
      / 4;

  record_unwind_protect (save_window_restore, tem);
  val = Fprogn (args);
  UNGCPRO;
  unbind_to (count);
  return val;
}

init_window_once ()
{
  extern Lisp_Object get_minibuffer ();
  Lisp_Object root_window;

  root_window = make_window ();
  minibuf_window = make_window ();

  XWINDOW (root_window)->next = minibuf_window;
  XWINDOW (minibuf_window)->prev = root_window;

  /* These values 9 and 10 are arbitrary,
     just so that there is "something there."
     Correct values are put in in init_xdisp */

  XFASTINT (XWINDOW (root_window)->width) = 10;
  XFASTINT (XWINDOW (minibuf_window)->width) = 10;

  XFASTINT (XWINDOW (root_window)->height) = 9;
  XFASTINT (XWINDOW (minibuf_window)->top) = 9;
  XFASTINT (XWINDOW (minibuf_window)->height) = 1;

  Fshow_buffer (root_window, Fcurrent_buffer ());
  Fshow_buffer (minibuf_window, get_minibuffer (0));

  selected_window = root_window;
}

syms_of_window ()
{
  Qwindowp = intern ("windowp");
  staticpro (&Qwindowp);

  /* Make sure all windows get marked */
  staticpro (&minibuf_window);

  DefBoolVar ("pop-up-windows", &pop_up_windows,
    "*Non-nil means display-buffer should make new windows.");
  pop_up_windows = 1;

  DefIntVar ("next-screen-context-lines", &next_screen_context_lines,
    "*Number of lines of continuity when scrolling by screenfuls.");
  next_screen_context_lines = 2;

  DefIntVar ("split-height-threshold", &split_height_threshold,
    "*display-buffer would prefer to split the largest window if this large.\n\
If there is only one window, it is split regardless of this value.");
  split_height_threshold = 500;

  DefIntVar ("window-min-height", &window_min_height,
    "*Delete any window less than this tall (including its mode line).");
  window_min_height = 4;

  DefIntVar ("window-min-width", &window_min_width,
    "*Delete any window less than this wide.");
  window_min_width = 10;

  defsubr (&Sselected_window);
  defsubr (&Swindowp);
  defsubr (&Spos_visible_in_window_p);
  defsubr (&Swindow_buffer);
  defsubr (&Swindow_height);
  defsubr (&Swindow_width);
  defsubr (&Swindow_hscroll);
  defsubr (&Sset_window_hscroll);
  defsubr (&Swindow_edges);
  defsubr (&Swindow_dot);
  defsubr (&Swindow_start);
  defsubr (&Sset_window_dot);
  defsubr (&Sset_window_start);
  defsubr (&Snext_window);
  defsubr (&Sprevious_window);
  defsubr (&Sother_window);
  defsubr (&Sget_lru_window);
  defsubr (&Sget_largest_window);
  defsubr (&Sget_buffer_window);
  defsubr (&Sdelete_other_windows);
  defsubr (&Sdelete_windows_on);
  defsubr (&Sreplace_buffer_in_windows);
  defsubr (&Sdelete_window);
  defsubr (&Sshow_buffer);
  defsubr (&Sselect_window);
  defsubr (&Sdisplay_buffer);
  defsubr (&Ssplit_window);
  defsubr (&Senlarge_window);
  defsubr (&Sshrink_window);
  defsubr (&Sscroll_up);
  defsubr (&Sscroll_down);
  defsubr (&Sscroll_left);
  defsubr (&Sscroll_right);
  defsubr (&Sscroll_other_window);
  defsubr (&Srecenter);
  defsubr (&Smove_to_window_line);
  defsubr (&Ssave_window_excursion);
}

keys_of_window ()
{
  defkey (CtlXmap, '1', "delete-other-windows");
  defkey (CtlXmap, '2', "split-window");
  defkey (CtlXmap, '0', "delete-window");
  defkey (CtlXmap, 'o', "other-window");
  defkey (CtlXmap, '^', "enlarge-window");
  defkey (CtlXmap, '<', "scroll-left");
  defkey (CtlXmap, '>', "scroll-right");

  defkey (GlobalMap, Ctl ('V'), "scroll-up");
  defkey (ESCmap, Ctl ('V'), "scroll-other-window");
  defkey (ESCmap, 'v', "scroll-down");

  defkey (GlobalMap, Ctl('L'), "recenter");
  defkey (ESCmap, 'r', "move-to-window-line");
}
