--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/indent.c	Mon Aug 13 08:45:50 2007 +0200
@@ -0,0 +1,671 @@
+/* Indentation functions.
+   Copyright (C) 1995 Board of Trustees, University of Illinois.
+   Copyright (C) 1985, 1986, 1987, 1988, 1992, 1993, 1994, 1995
+   Free Software Foundation, Inc.
+
+This file is part of XEmacs.
+
+XEmacs is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 2, or (at your option) any
+later version.
+
+XEmacs is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with XEmacs; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
+
+/* This file has been Mule-ized. */
+
+/* Synched up with: 19.30.  Diverges significantly from FSF. */
+
+
+#include <config.h>
+#include "lisp.h"
+
+#include "buffer.h"
+#include "device.h"
+#include "extents.h"
+#include "faces.h"
+#include "frame.h"
+#include "glyphs.h"
+#include "insdel.h"
+#ifdef REGION_CACHE_NEEDS_WORK
+#include "region-cache.h"
+#endif
+#include "window.h"
+
+/* Indentation can insert tabs if this is non-zero;
+   otherwise always uses spaces */
+int indent_tabs_mode;
+
+/* Avoid recalculation by remembering things in these variables. */
+
+/* Last value returned by current_column.
+
+   Some things set last_known_column_point to -1
+   to mark the memoized value as invalid */
+static int last_known_column;
+
+/* Last buffer searched by current_column */
+static struct buffer *last_known_column_buffer;
+
+/* Value of point when current_column was called */
+static Bufpos last_known_column_point;
+
+/* Value of MODIFF when current_column was called */
+static int last_known_column_modified;
+
+static Bufpos
+last_visible_position (Bufpos pos, struct buffer *buf)
+{
+  Lisp_Object buffer;
+  Lisp_Object value;
+
+  XSETBUFFER (buffer, buf);
+  value = Fprevious_single_property_change (make_int (pos), Qinvisible,
+					    buffer, Qnil);
+  if (NILP (value))
+    return 0; /* no visible position found */
+  else
+    /* #### bug bug bug!!! This will return the position of the beginning
+       of an invisible extent; this extent is very likely to be start-closed,
+       and thus the spaces inserted in `indent-to' will go inside the
+       invisible extent.
+
+       Not sure what the correct solution is here.  Rethink indent-to? */
+    return XINT (value);
+}
+
+#ifdef REGION_CACHE_NEEDS_WORK
+
+/* Allocate or free the width run cache, as requested by the current
+   state of current_buffer's cache_long_line_scans variable.  */
+static void
+width_run_cache_on_off (struct buffer *buf)
+{
+  if (NILP (buf->cache_long_line_scans))
+    {
+      /* It should be off.  */
+      if (buf->width_run_cache)
+        {
+          free_region_cache (buf->width_run_cache);
+          buf->width_run_cache = 0;
+          buf->width_table = Qnil;
+        }
+    }
+  else
+    {
+      /* It should be on.  */
+      if (buf->width_run_cache == 0)
+        {
+          buf->width_run_cache = new_region_cache ();
+          recompute_width_table (buf, buffer_display_table ());
+        }
+    }
+}
+
+#endif /* REGION_CACHE_NEEDS_WORK */
+
+
+/* Cancel any recorded value of the horizontal position.  */
+ 
+void
+invalidate_current_column (void)
+{
+  last_known_column_point = -1;
+}
+
+int
+column_at_point (struct buffer *buf, Bufpos init_pos, int cur_col)
+{
+  int col;
+  int tab_seen;
+  int tab_width = XINT (buf->tab_width);
+  int post_tab;
+  Bufpos pos = init_pos;
+
+  if (tab_width <= 0 || tab_width > 1000) tab_width = 8;
+  col = tab_seen = post_tab = 0;
+
+  while (1)
+    {
+      if (pos <= BUF_BEGV (buf))
+	break;
+
+      pos--;
+      if (BUF_FETCH_CHAR (buf, pos) == '\t')
+	{
+	  if (tab_seen)
+	    col = ((col + tab_width) / tab_width) * tab_width;
+
+	  post_tab += col;
+	  col = 0;
+	  tab_seen = 1;
+	}
+      else if (BUF_FETCH_CHAR (buf, pos) == '\n' ||
+	       (EQ (buf->selective_display, Qt) &&
+		BUF_FETCH_CHAR (buf, pos) == '\r'))
+	break;
+      else
+	{
+	  /* #### This needs updating to handle the new redisplay. */
+	  /* #### FSFmacs looks at ctl_arrow, display tables.
+	     We need to do similar. */
+#if 0
+	  displayed_glyphs = glyphs_from_bufpos (sel_frame, buf,
+						 XWINDOW (selected_window),
+						 pos, dp, 0, col, 0, 0, 0);
+	  col += (displayed_glyphs->columns
+		  - (displayed_glyphs->begin_columns
+		     + displayed_glyphs->end_columns));
+#else
+	  col++;
+#endif
+	}
+    }
+
+  if (tab_seen)
+    {
+      col = ((col + tab_width) / tab_width) * tab_width;
+      col += post_tab;
+    }
+
+  if (cur_col)
+    {
+      last_known_column_buffer = buf;
+      last_known_column = col;
+      last_known_column_point = BUF_PT (buf);
+      last_known_column_modified = BUF_MODIFF (buf);
+    }
+
+  return col;
+}
+
+int
+current_column (struct buffer *buf)
+{
+  if (buf == last_known_column_buffer
+      && BUF_PT (buf) == last_known_column_point
+      && BUF_MODIFF (buf) == last_known_column_modified)
+    return last_known_column;
+
+  return column_at_point (buf, BUF_PT (buf), 1);
+}
+
+DEFUN ("current-column", Fcurrent_column, Scurrent_column, 0, 1, 0 /*
+Return the horizontal position of point.  Beginning of line is column 0.
+This is calculated by adding together the widths of all the displayed
+ representations of the character between the start of the previous line
+ and point. (e.g. control characters will have a width of 2 or 4, tabs
+ will have a variable width.)
+Ignores finite width of frame, which means that this function may return
+ values greater than (frame-width).
+Whether the line is visible (if `selective-display' is t) has no effect;
+ however, ^M is treated as end of line when `selective-display' is t.
+If BUFFER is nil, the current buffer is assumed.
+*/ )
+  (buffer)
+     Lisp_Object buffer;
+{
+  return (make_int (current_column (decode_buffer (buffer, 0))));
+}
+
+
+DEFUN ("indent-to", Findent_to, Sindent_to, 1, 3, "NIndent to column: " /*
+Indent from point with tabs and spaces until COLUMN is reached.
+Optional second argument MIN says always do at least MIN spaces
+ even if that goes past COLUMN; by default, MIN is zero.
+If BUFFER is nil, the current buffer is assumed.
+*/ )
+  (col, minimum, buffer)
+     Lisp_Object col, minimum, buffer;
+{
+  /* This function can GC */
+  int mincol;
+  int fromcol;
+  struct buffer *buf = decode_buffer (buffer, 0);
+  int tab_width = XINT (buf->tab_width);
+  Bufpos opoint = 0;
+
+  CHECK_INT (col);
+  if (NILP (minimum))
+    minimum = Qzero;
+  else
+    CHECK_INT (minimum);
+
+  XSETBUFFER (buffer, buf);
+  
+  fromcol = current_column (buf);
+  mincol = fromcol + XINT (minimum);
+  if (mincol < XINT (col)) mincol = XINT (col);
+
+  if (fromcol == mincol)
+    return make_int (mincol);
+
+  if (tab_width <= 0 || tab_width > 1000) tab_width = 8;
+  
+  if (!NILP (Fextent_at (make_int (BUF_PT (buf)), buffer, Qinvisible,
+			 Qnil, Qnil)))
+    {
+      Bufpos last_visible = last_visible_position (BUF_PT (buf), buf);
+
+      opoint = BUF_PT (buf);
+      if (last_visible >= BUF_BEGV (buf))
+	BUF_SET_PT (buf, last_visible);
+      else 
+        error ("Visible portion of buffer not modifiable");
+    }
+
+  if (indent_tabs_mode)
+    {
+      int n = mincol / tab_width - fromcol / tab_width;
+      if (n != 0)
+	{
+	  Finsert_char (make_char ('\t'), make_int (n), Qnil, buffer);
+
+	  fromcol = (mincol / tab_width) * tab_width;
+	}
+    }
+
+  Finsert_char (make_char (' '), make_int (mincol - fromcol), Qnil, buffer);
+
+  last_known_column_buffer = buf;
+  last_known_column = mincol;
+  last_known_column_point = BUF_PT (buf);
+  last_known_column_modified = BUF_MODIFF (buf);
+
+  /* Not in FSF: */
+  if (opoint > 0)
+    BUF_SET_PT (buf, opoint);
+
+  return (make_int (mincol));
+}
+
+int
+bi_spaces_at_point (struct buffer *b, Bytind bi_pos)
+{
+  Bytind bi_end = BI_BUF_ZV (b);
+  int col = 0;
+  Emchar c;
+  int tab_width = XINT (b->tab_width);
+
+  if (tab_width <= 0 || tab_width > 1000)
+    tab_width = 8;
+
+  while (bi_pos < bi_end &&
+	 (c = BI_BUF_FETCH_CHAR (b, bi_pos),
+	  (c == '\t'
+	   ? (col += tab_width - col % tab_width)
+	   : (c == ' ' ? ++col : 0))))
+    INC_BYTIND (b, bi_pos);
+
+  return col;
+}
+
+
+DEFUN ("current-indentation", Fcurrent_indentation, Scurrent_indentation,
+  0, 1, 0 /*
+Return the indentation of the current line.
+This is the horizontal position of the character
+following any initial whitespace.
+*/ )
+  (buffer)
+  Lisp_Object buffer;
+{
+  struct buffer *buf = decode_buffer (buffer, 0);
+  Bufpos pos = find_next_newline (buf, BUF_PT (buf), -1);
+
+  XSETBUFFER (buffer, buf);
+
+  if (!NILP (Fextent_at (make_int (pos), buffer, Qinvisible, Qnil, Qnil)))
+    return Qzero;
+
+  return make_int (bi_spaces_at_point (buf, bufpos_to_bytind (buf, pos)));
+}
+
+
+DEFUN ("move-to-column", Fmove_to_column, Smove_to_column, 1, 3, 0 /*
+Move point to column COLUMN in the current line.
+The column of a character is calculated by adding together the widths
+as displayed of the previous characters in the line.
+This function ignores line-continuation;
+there is no upper limit on the column number a character can have
+and horizontal scrolling has no effect.
+
+If specified column is within a character, point goes after that character.
+If it's past end of line, point goes to end of line.
+
+A non-nil second (optional) argument FORCE means, if the line
+is too short to reach column COLUMN then add spaces/tabs to get there,
+and if COLUMN is in the middle of a tab character, change it to spaces.
+Returns the actual column that it moved to.
+*/ )
+  (column, force, buffer)
+     Lisp_Object column, force, buffer;
+{
+  /* This function can GC */
+  Bufpos pos;
+  struct buffer *buf = decode_buffer (buffer, 0);
+  int col = current_column (buf);
+  int goal;
+  Bufpos end;
+  int tab_width = XINT (buf->tab_width);
+
+  int prev_col = 0;
+  Emchar c = 0;
+
+  XSETBUFFER (buffer, buf);
+  if (tab_width <= 0 || tab_width > 1000) tab_width = 8;
+  CHECK_NATNUM (column);
+  goal = XINT (column);
+
+ retry:
+  pos = BUF_PT (buf);
+  end = BUF_ZV (buf);
+
+  /* If we're starting past the desired column,
+     back up to beginning of line and scan from there.  */
+  if (col > goal)
+    {
+      pos = find_next_newline (buf, pos, -1);
+      col = 0;
+    }
+
+  while (col < goal && pos < end)
+    {
+      c = BUF_FETCH_CHAR (buf, pos);
+      if (c == '\n')
+	break;
+      if (c == '\r' && EQ (buf->selective_display, Qt))
+	break;
+      if (c == '\t')
+	{
+	  prev_col = col;
+	  col += tab_width;
+	  col = col / tab_width * tab_width;
+	}
+      else
+	{
+	  /* #### oh for the days of the complete new redisplay */
+	  /* #### FSFmacs looks at ctl_arrow, display tables.
+	     We need to do similar. */
+#if 0
+	  displayed_glyphs = glyphs_from_bufpos (selected_frame (),
+						 buf,
+						 XWINDOW (Fselected_window (Qnil)),
+						 pos, dp, 0, col, 0, 0, 0);
+	  col += (displayed_glyphs->columns
+		  - (displayed_glyphs->begin_columns
+		     + displayed_glyphs->end_columns));
+#else
+	  col++;
+#endif
+	}
+
+      pos++;
+    }
+
+  BUF_SET_PT (buf, pos);
+
+  /* If a tab char made us overshoot, change it to spaces
+     and scan through it again.  */
+  if (!NILP (force) && col > goal && c == '\t' && prev_col < goal)
+    {
+      buffer_delete_range (buf, BUF_PT (buf) - 1, BUF_PT (buf), 0);
+      Findent_to (make_int (col - 1), Qzero, buffer);
+      buffer_insert_emacs_char (buf, ' ');
+      goto retry;
+    }
+
+  /* If line ends prematurely, add space to the end.  */
+  if (col < goal && !NILP (force))
+    {
+      col = goal;
+      Findent_to (make_int (col), Qzero, buffer);
+    }
+
+  last_known_column_buffer = buf;
+  last_known_column = col;
+  last_known_column_point = BUF_PT (buf);
+  last_known_column_modified = BUF_MODIFF (buf);
+
+  return (make_int (col));
+}
+
+#if 0 /* #### OK boys, this function needs to be present, I think.
+	 It was there before the 19.12 redisplay rewrite. */
+
+xxDEFUN ("compute-motion", Fcompute_motion, Scompute_motion, 7, 7, 0 /*
+  "Scan through the current buffer, calculating screen position.
+Scan the current buffer forward from offset FROM,
+assuming it is at position FROMPOS--a cons of the form (HPOS . VPOS)--
+to position TO or position TOPOS--another cons of the form (HPOS . VPOS)--
+and return the ending buffer position and screen location.
+
+There are three additional arguments:
+
+WIDTH is the number of columns available to display text;
+this affects handling of continuation lines.
+This is usually the value returned by `window-width', less one (to allow
+for the continuation glyph).
+
+OFFSETS is either nil or a cons cell (HSCROLL . TAB-OFFSET).
+HSCROLL is the number of columns not being displayed at the left
+margin; this is usually taken from a window's hscroll member.
+TAB-OFFSET is the number of columns of the first tab that aren't
+being displayed, perhaps because the line was continued within it.
+If OFFSETS is nil, HSCROLL and TAB-OFFSET are assumed to be zero.
+
+WINDOW is the window to operate on.  Currently this is used only to
+find the display table.  It does not matter what buffer WINDOW displays;
+`compute-motion' always operates on the current buffer.
+
+The value is a list of five elements:
+  (POS HPOS VPOS PREVHPOS CONTIN)
+POS is the buffer position where the scan stopped.
+VPOS is the vertical position where the scan stopped.
+HPOS is the horizontal position where the scan stopped.
+
+PREVHPOS is the horizontal position one character back from POS.
+CONTIN is t if a line was continued after (or within) the previous character.
+
+For example, to find the buffer position of column COL of line LINE
+of a certain window, pass the window's starting location as FROM
+and the window's upper-left coordinates as FROMPOS.
+Pass the buffer's (point-max) as TO, to limit the scan to the end of the
+visible section of the buffer, and pass LINE and COL as TOPOS.
+*/ )
+  (from, frompos, to, topos, width, offsets, window)
+     Lisp_Object from, frompos, to, topos;
+     Lisp_Object width, offsets, window;
+{
+  Lisp_Object bufpos, hpos, vpos, prevhpos, contin;
+  struct position *pos;
+  int hscroll, tab_offset;
+  struct window *w = decode_window (window);
+
+  CHECK_INT_COERCE_MARKER (from);
+  CHECK_CONS (frompos);
+  CHECK_INT (XCAR (frompos));
+  CHECK_INT (XCDR (frompos));
+  CHECK_INT_COERCE_MARKER (to);
+  CHECK_CONS (topos);
+  CHECK_INT (XCAR (topos));
+  CHECK_INT (XCDR (topos));
+  CHECK_INT (width);
+  if (!NILP (offsets))
+    {
+      CHECK_CONS (offsets);
+      CHECK_INT (XCAR (offsets));
+      CHECK_INT (XCDR (offsets));
+      hscroll = XINT (XCAR (offsets));
+      tab_offset = XINT (XCDR (offsets));
+    }
+  else
+    hscroll = tab_offset = 0;
+
+  pos = compute_motion (XINT (from), XINT (XCDR (frompos)),
+			XINT (XCAR (frompos)),
+			XINT (to), XINT (XCDR (topos)),
+			XINT (XCAR (topos)),
+			XINT (width), hscroll, tab_offset, w);
+
+  XSETINT (bufpos, pos->bufpos);
+  XSETINT (hpos, pos->hpos);
+  XSETINT (vpos, pos->vpos);
+  XSETINT (prevhpos, pos->prevhpos);
+
+  return list5 (bufpos,
+		hpos,
+		vpos,
+		prevhpos,
+		pos->contin ? Qt : Qnil);
+
+}
+
+#endif /* 0 */
+
+/*****************************************************************************
+ vmotion
+
+ Given a starting position ORIG, move point VTARGET lines in WINDOW.
+ Returns the new value for point.  If the arg ret_vpos is not nil, it is
+ taken to be a pointer to an int and the number of lines actually moved is
+ returned in it.
+ ****************************************************************************/
+Bufpos
+vmotion (struct window *w, Bufpos orig, int vtarget, int *ret_vpos)
+{
+  struct buffer *b = XBUFFER (w->buffer);
+  int elt;
+
+  elt = point_in_line_start_cache (w, orig, (vtarget < 0
+					     ? -vtarget
+					     : vtarget));
+
+  /* #### This assertion must be true before the if statements are hit
+     but may possibly be wrong after the call to
+     point_in_line_start_cache if orig is outside of the visible
+     region of the buffer.  Handle this. */
+  assert (elt >= 0);
+
+  /* Moving downward. */
+  if (vtarget > 0)
+    {
+      int cur_line = Dynarr_length (w->line_start_cache) - 1 - elt;
+      Bufpos ret_pt;
+
+      if (cur_line > vtarget)
+	cur_line = vtarget;
+
+      /* The traditional FSF behavior is to return the end of buffer
+         position if we couldn't move far enough because we hit it.  */
+      if (cur_line < vtarget)
+	ret_pt = BUF_ZV (b);
+      else
+	ret_pt = Dynarr_atp (w->line_start_cache, cur_line + elt)->start;
+
+      while (ret_pt > BUF_ZV (b) && cur_line > 0)
+	{
+	  cur_line--;
+	  ret_pt = Dynarr_atp (w->line_start_cache, cur_line + elt)->start;
+	}
+
+      if (ret_vpos) *ret_vpos = cur_line;
+      return (ret_pt);
+    }
+  else if (vtarget < 0)
+    {
+      if (elt < -vtarget)
+	{
+	  if (ret_vpos) *ret_vpos = -elt;
+	  /* #### This should be BUF_BEGV (b), right? */
+	  return (Dynarr_atp (w->line_start_cache, 0)->start);
+	}
+      else
+	{
+	  if (ret_vpos) *ret_vpos = vtarget;
+	  return (Dynarr_atp (w->line_start_cache, elt + vtarget)->start);
+	}
+    }
+  else
+    {
+      /* No vertical motion requested so we just return the position
+         of the beginning of the current line. */
+      if (ret_vpos) *ret_vpos = 0;
+
+      return (Dynarr_atp (w->line_start_cache, elt)->start);
+    }
+
+  RETURN_NOT_REACHED(0)	/* shut up compiler */
+}
+
+DEFUN ("vertical-motion", Fvertical_motion, Svertical_motion, 1, 2, 0 /*
+Move to start of frame line LINES lines down.
+If LINES is negative, this is moving up.
+
+The optional second argument WINDOW specifies the window to use for
+parameters such as width, horizontal scrolling, and so on.
+the default is the selected window.
+Note that `vertical-motion' sets WINDOW's buffer's point, not
+WINDOW's point. (This differs from FSF Emacs, which buggily always
+sets current buffer's point, regardless of WINDOW.)
+
+Sets point to position found; this may be start of line
+ or just the start of a continuation line.
+Returns number of lines moved; may be closer to zero than LINES
+ if beginning or end of buffer was reached.
+Optional second argument is WINDOW to move in.
+*/ )
+  (lines, window)
+     Lisp_Object lines, window;
+{
+  if (NILP (window))
+    window = Fselected_window (Qnil);
+  CHECK_WINDOW (window);
+  {
+    Bufpos bufpos;
+    int vpos;
+    struct window *w  = XWINDOW (window);
+
+    CHECK_INT (lines);
+
+    bufpos = vmotion (XWINDOW (window), BUF_PT (XBUFFER (w->buffer)),
+		      XINT (lines), &vpos);
+
+    /* Note that the buffer's point is set, not the window's point. */
+    BUF_SET_PT (XBUFFER (w->buffer), bufpos);
+
+    return make_int (vpos);
+  }
+}
+
+
+void
+syms_of_indent (void)
+{
+  defsubr (&Scurrent_indentation);
+  defsubr (&Sindent_to);
+  defsubr (&Scurrent_column);
+  defsubr (&Smove_to_column);
+#if 0 /* #### */
+  defsubr (&Scompute_motion);
+#endif
+  defsubr (&Svertical_motion);
+}
+
+void
+vars_of_indent (void)
+{
+  DEFVAR_BOOL ("indent-tabs-mode", &indent_tabs_mode /*
+*Indentation can insert tabs if this is non-nil.
+Setting this variable automatically makes it local to the current buffer.
+*/ );
+  indent_tabs_mode = 1;
+}