xemacs-beta: src/extents.c comparison

comparison src/extents.c @ 428:3ecd8885ac67 r21-2-22

Import from CVS: tag r21-2-22

author	cvs
date	Mon, 13 Aug 2007 11:28:15 +0200
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children	84b14dcb0985

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+:3ecd8885ac67
+/* Copyright (c) 1994, 1995 Free Software Foundation, Inc.
+Copyright (c) 1995 Sun Microsystems, Inc.
+Copyright (c) 1995, 1996 Ben Wing.
+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.  */
+/* Synched up with: Not in FSF. */
+/* This file has been Mule-ized. */
+/* Written by Ben Wing <ben@xemacs.org>.
+[Originally written by some people at Lucid.
+Hacked on by jwz.
+Start/end-open stuff added by John Rose (john.rose@eng.sun.com).
+Rewritten from scratch by Ben Wing, December 1994.] */
+/* Commentary:
+Extents are regions over a buffer, with a start and an end position
+denoting the region of the buffer included in the extent.  In
+addition, either end can be closed or open, meaning that the endpoint
+is or is not logically included in the extent.  Insertion of a character
+at a closed endpoint causes the character to go inside the extent;
+insertion at an open endpoint causes the character to go outside.
+Extent endpoints are stored using memory indices (see insdel.c),
+to minimize the amount of adjusting that needs to be done when
+characters are inserted or deleted.
+(Formerly, extent endpoints at the gap could be either before or
+after the gap, depending on the open/closedness of the endpoint.
+The intent of this was to make it so that insertions would
+automatically go inside or out of extents as necessary with no
+further work needing to be done.  It didn't work out that way,
+however, and just ended up complexifying and buggifying all the
+rest of the code.)
+Extents are compared using memory indices.  There are two orderings
+for extents and both orders are kept current at all times.  The normal
+or "display" order is as follows:
+Extent A is "less than" extent B, that is, earlier in the display order,
+if:    A-start < B-start,
+or if: A-start = B-start, and A-end > B-end
+So if two extents begin at the same position, the larger of them is the
+earlier one in the display order (EXTENT_LESS is true).
+For the e-order, the same thing holds: Extent A is "less than" extent B
+in e-order, that is, later in the buffer,
+if:    A-end < B-end,
+or if: A-end = B-end, and A-start > B-start
+So if two extents end at the same position, the smaller of them is the
+earlier one in the e-order (EXTENT_E_LESS is true).
+The display order and the e-order are complementary orders: any
+theorem about the display order also applies to the e-order if you
+swap all occurrences of "display order" and "e-order", "less than"
+and "greater than", and "extent start" and "extent end".
+Extents can be zero-length, and will end up that way if their endpoints
+are explicitly set that way or if their detachable property is nil
+and all the text in the extent is deleted. (The exception is open-open
+zero-length extents, which are barred from existing because there is
+no sensible way to define their properties.  Deletion of the text in
+an open-open extent causes it to be converted into a closed-open
+extent.)  Zero-length extents are primarily used to represent
+annotations, and behave as follows:
+1) Insertion at the position of a zero-length extent expands the extent
+if both endpoints are closed; goes after the extent if it is closed-open;
+and goes before the extent if it is open-closed.
+2) Deletion of a character on a side of a zero-length extent whose
+corresponding endpoint is closed causes the extent to be detached if
+it is detachable; if the extent is not detachable or the corresponding
+endpoint is open, the extent remains in the buffer, moving as necessary.
+Note that closed-open, non-detachable zero-length extents behave exactly
+like markers and that open-closed, non-detachable zero-length extents
+behave like the "point-type" marker in Mule.
+#### The following information is wrong in places.
+More about the different orders:
+--------------------------------
+The extents in a buffer are ordered by "display order" because that
+is that order that the redisplay mechanism needs to process them in.
+The e-order is an auxiliary ordering used to facilitate operations
+over extents.  The operations that can be performed on the ordered
+list of extents in a buffer are
+1) Locate where an extent would go if inserted into the list.
+2) Insert an extent into the list.
+3) Remove an extent from the list.
+4) Map over all the extents that overlap a range.
+(4) requires being able to determine the first and last extents
+that overlap a range.
+NOTE: "overlap" is used as follows:
+-- two ranges overlap if they have at least one point in common.
+Whether the endpoints are open or closed makes a difference here.
+-- a point overlaps a range if the point is contained within the
+range; this is equivalent to treating a point P as the range
+[P, P].
+-- In the case of an *extent* overlapping a point or range, the
+extent is normally treated as having closed endpoints.  This
+applies consistently in the discussion of stacks of extents
+and such below.  Note that this definition of overlap is not
+necessarily consistent with the extents that `map-extents'
+maps over, since `map-extents' sometimes pays attention to
+whether the endpoints of an extents are open or closed.
+But for our purposes, it greatly simplifies things to treat
+all extents as having closed endpoints.
+First, define >, <, <=, etc. as applied to extents to mean
+comparison according to the display order.  Comparison between an
+extent E and an index I means comparison between E and the range
+[I, I].
+Also define e>, e<, e<=, etc. to mean comparison according to the
+e-order.
+For any range R, define R(0) to be the starting index of the range
+and R(1) to be the ending index of the range.
+For any extent E, define E(next) to be the extent directly following
+E, and E(prev) to be the extent directly preceding E.  Assume
+E(next) and E(prev) can be determined from E in constant time.
+(This is because we store the extent list as a doubly linked
+list.)
+Similarly, define E(e-next) and E(e-prev) to be the extents
+directly following and preceding E in the e-order.
+Now:
+Let R be a range.
+Let F be the first extent overlapping R.
+Let L be the last extent overlapping R.
+Theorem 1: R(1) lies between L and L(next), i.e. L <= R(1) < L(next).
+This follows easily from the definition of display order.  The
+basic reason that this theorem applies is that the display order
+sorts by increasing starting index.
+Therefore, we can determine L just by looking at where we would
+insert R(1) into the list, and if we know F and are moving forward
+over extents, we can easily determine when we've hit L by comparing
+the extent we're at to R(1).
+Theorem 2: F(e-prev) e< [1, R(0)] e<= F.
+This is the analog of Theorem 1, and applies because the e-order
+sorts by increasing ending index.
+Therefore, F can be found in the same amount of time as operation (1),
+i.e. the time that it takes to locate where an extent would go if
+inserted into the e-order list.
+If the lists were stored as balanced binary trees, then operation (1)
+would take logarithmic time, which is usually quite fast.  However,
+currently they're stored as simple doubly-linked lists, and instead
+we do some caching to try to speed things up.
+Define a "stack of extents" (or "SOE") as the set of extents
+(ordered in the display order) that overlap an index I, together with
+the SOE's "previous" extent, which is an extent that precedes I in
+the e-order. (Hopefully there will not be very many extents between
+I and the previous extent.)
+Now:
+Let I be an index, let S be the stack of extents on I, let F be
+the first extent in S, and let P be S's previous extent.
+Theorem 3: The first extent in S is the first extent that overlaps
+any range [I, J].
+Proof: Any extent that overlaps [I, J] but does not include I must
+have a start index > I, and thus be greater than any extent in S.
+Therefore, finding the first extent that overlaps a range R is the
+same as finding the first extent that overlaps R(0).
+Theorem 4: Let I2 be an index such that I2 > I, and let F2 be the
+first extent that overlaps I2.  Then, either F2 is in S or F2 is
+greater than any extent in S.
+Proof: If F2 does not include I then its start index is greater
+than I and thus it is greater than any extent in S, including F.
+Otherwise, F2 includes I and thus is in S, and thus F2 >= F.
+*/
+#include <config.h>
+#include "lisp.h"
+#include "buffer.h"
+#include "debug.h"
+#include "device.h"
+#include "elhash.h"
+#include "extents.h"
+#include "faces.h"
+#include "frame.h"
+#include "glyphs.h"
+#include "insdel.h"
+#include "keymap.h"
+#include "opaque.h"
+#include "process.h"
+#include "redisplay.h"
+/* ------------------------------- */
+/*            gap array            */
+/* ------------------------------- */
+/* Note that this object is not extent-specific and should perhaps be
+moved into another file. */
+/* Holds a marker that moves as elements in the array are inserted and
+deleted, similar to standard markers. */
+typedef struct gap_array_marker
+{
+int pos;
+struct gap_array_marker *next;
+} Gap_Array_Marker;
+/* Holds a "gap array", which is an array of elements with a gap located
+in it.  Insertions and deletions with a high degree of locality
+are very fast, essentially in constant time.  Array positions as
+used and returned in the gap array functions are independent of
+the gap. */
+typedef struct gap_array
+{
+char *array;
+int gap;
+int gapsize;
+int numels;
+int elsize;
+Gap_Array_Marker *markers;
+} Gap_Array;
+static Gap_Array_Marker *gap_array_marker_freelist;
+/* Convert a "memory position" (i.e. taking the gap into account) into
+the address of the element at (i.e. after) that position.  "Memory
+positions" are only used internally and are of type Memind.
+"Array positions" are used externally and are of type int. */
+#define GAP_ARRAY_MEMEL_ADDR(ga, memel) ((ga)->array + (ga)->elsize*(memel))
+/* Number of elements currently in a gap array */
+#define GAP_ARRAY_NUM_ELS(ga) ((ga)->numels)
+#define GAP_ARRAY_ARRAY_TO_MEMORY_POS(ga, pos) \
+((pos) <= (ga)->gap ? (pos) : (pos) + (ga)->gapsize)
+#define GAP_ARRAY_MEMORY_TO_ARRAY_POS(ga, pos) \
+((pos) <= (ga)->gap ? (pos) : (pos) - (ga)->gapsize)
+/* Convert an array position into the address of the element at
+(i.e. after) that position. */
+#define GAP_ARRAY_EL_ADDR(ga, pos) ((pos) < (ga)->gap ? \
+GAP_ARRAY_MEMEL_ADDR(ga, pos) : \
+GAP_ARRAY_MEMEL_ADDR(ga, (pos) + (ga)->gapsize))
+/* ------------------------------- */
+/*          extent list            */
+/* ------------------------------- */
+typedef struct extent_list_marker
+{
+Gap_Array_Marker *m;
+int endp;
+struct extent_list_marker *next;
+} Extent_List_Marker;
+typedef struct extent_list
+{
+Gap_Array *start;
+Gap_Array *end;
+Extent_List_Marker *markers;
+} Extent_List;
+static Extent_List_Marker *extent_list_marker_freelist;
+#define EXTENT_LESS_VALS(e,st,nd) ((extent_start (e) < (st)) || \
+				   ((extent_start (e) == (st)) && \
+				    (extent_end (e) > (nd))))
+#define EXTENT_EQUAL_VALS(e,st,nd) ((extent_start (e) == (st)) && \
+				    (extent_end (e) == (nd)))
+#define EXTENT_LESS_EQUAL_VALS(e,st,nd) ((extent_start (e) < (st)) || \
+					 ((extent_start (e) == (st)) && \
+					  (extent_end (e) >= (nd))))
+/* Is extent E1 less than extent E2 in the display order? */
+#define EXTENT_LESS(e1,e2) \
+EXTENT_LESS_VALS (e1, extent_start (e2), extent_end (e2))
+/* Is extent E1 equal to extent E2? */
+#define EXTENT_EQUAL(e1,e2) \
+EXTENT_EQUAL_VALS (e1, extent_start (e2), extent_end (e2))
+/* Is extent E1 less than or equal to extent E2 in the display order? */
+#define EXTENT_LESS_EQUAL(e1,e2) \
+EXTENT_LESS_EQUAL_VALS (e1, extent_start (e2), extent_end (e2))
+#define EXTENT_E_LESS_VALS(e,st,nd) ((extent_end (e) < (nd)) || \
+				     ((extent_end (e) == (nd)) && \
+				      (extent_start (e) > (st))))
+#define EXTENT_E_LESS_EQUAL_VALS(e,st,nd) ((extent_end (e) < (nd)) || \
+					   ((extent_end (e) == (nd)) && \
+					    (extent_start (e) >= (st))))
+/* Is extent E1 less than extent E2 in the e-order? */
+#define EXTENT_E_LESS(e1,e2) \
+	EXTENT_E_LESS_VALS(e1, extent_start (e2), extent_end (e2))
+/* Is extent E1 less than or equal to extent E2 in the e-order? */
+#define EXTENT_E_LESS_EQUAL(e1,e2) \
+EXTENT_E_LESS_EQUAL_VALS (e1, extent_start (e2), extent_end (e2))
+#define EXTENT_GAP_ARRAY_AT(ga, pos) (* (EXTENT *) GAP_ARRAY_EL_ADDR(ga, pos))
+/* ------------------------------- */
+/*    auxiliary extent structure   */
+/* ------------------------------- */
+struct extent_auxiliary extent_auxiliary_defaults;
+/* ------------------------------- */
+/*     buffer-extent primitives    */
+/* ------------------------------- */
+typedef struct stack_of_extents
+{
+Extent_List *extents;
+Memind pos; /* Position of stack of extents.  EXTENTS is the list of
+		 all extents that overlap this position.  This position
+		 can be -1 if the stack of extents is invalid (this
+		 happens when a buffer is first created or a string's
+		 stack of extents is created [a string's stack of extents
+		 is nuked when a GC occurs, to conserve memory]). */
+} Stack_Of_Extents;
+/* ------------------------------- */
+/*           map-extents           */
+/* ------------------------------- */
+typedef int Endpoint_Index;
+#define memind_to_startind(x, start_open) \
+((Endpoint_Index) (((x) << 1) + !!(start_open)))
+#define memind_to_endind(x, end_open) \
+((Endpoint_Index) (((x) << 1) - !!(end_open)))
+/* Combination macros */
+#define bytind_to_startind(buf, x, start_open) \
+memind_to_startind (bytind_to_memind (buf, x), start_open)
+#define bytind_to_endind(buf, x, end_open) \
+memind_to_endind (bytind_to_memind (buf, x), end_open)
+/* ------------------------------- */
+/*    buffer-or-string primitives  */
+/* ------------------------------- */
+/* Similar for Bytinds and start/end indices. */
+#define buffer_or_string_bytind_to_startind(obj, ind, start_open)	\
+memind_to_startind (buffer_or_string_bytind_to_memind (obj, ind),	\
+		      start_open)
+#define buffer_or_string_bytind_to_endind(obj, ind, end_open)		\
+memind_to_endind (buffer_or_string_bytind_to_memind (obj, ind),	\
+		    end_open)
+/* ------------------------------- */
+/*      Lisp-level functions       */
+/* ------------------------------- */
+/* flags for decode_extent() */
+#define DE_MUST_HAVE_BUFFER 1
+#define DE_MUST_BE_ATTACHED 2
+Lisp_Object Vlast_highlighted_extent;
+int mouse_highlight_priority;
+Lisp_Object Qextentp;
+Lisp_Object Qextent_live_p;
+Lisp_Object Qall_extents_closed;
+Lisp_Object Qall_extents_open;
+Lisp_Object Qall_extents_closed_open;
+Lisp_Object Qall_extents_open_closed;
+Lisp_Object Qstart_in_region;
+Lisp_Object Qend_in_region;
+Lisp_Object Qstart_and_end_in_region;
+Lisp_Object Qstart_or_end_in_region;
+Lisp_Object Qnegate_in_region;
+Lisp_Object Qdetached;
+Lisp_Object Qdestroyed;
+Lisp_Object Qbegin_glyph;
+Lisp_Object Qend_glyph;
+Lisp_Object Qstart_open;
+Lisp_Object Qend_open;
+Lisp_Object Qstart_closed;
+Lisp_Object Qend_closed;
+Lisp_Object Qread_only;
+/* Qhighlight defined in general.c */
+Lisp_Object Qunique;
+Lisp_Object Qduplicable;
+Lisp_Object Qdetachable;
+Lisp_Object Qpriority;
+Lisp_Object Qmouse_face;
+Lisp_Object Qinitial_redisplay_function;
+Lisp_Object Qglyph_layout;  /* This exists only for backwards compatibility. */
+Lisp_Object Qbegin_glyph_layout, Qend_glyph_layout;
+Lisp_Object Qoutside_margin;
+Lisp_Object Qinside_margin;
+Lisp_Object Qwhitespace;
+/* Qtext defined in general.c */
+Lisp_Object Qcopy_function;
+Lisp_Object Qpaste_function;
+/* The idea here is that if we're given a list of faces, we
+need to "memoize" this so that two lists of faces that are `equal'
+turn into the same object.  When `set-extent-face' is called, we
+"memoize" into a list of actual faces; when `extent-face' is called,
+we do a reverse lookup to get the list of symbols. */
+static Lisp_Object canonicalize_extent_property (Lisp_Object prop,
+						 Lisp_Object value);
+Lisp_Object Vextent_face_memoize_hash_table;
+Lisp_Object Vextent_face_reverse_memoize_hash_table;
+Lisp_Object Vextent_face_reusable_list;
+/* FSFmacs bogosity */
+Lisp_Object Vdefault_text_properties;
+EXFUN (Fextent_properties, 1);
+EXFUN (Fset_extent_property, 3);
+/************************************************************************/
+/*                       Generalized gap array                          */
+/************************************************************************/
+/* This generalizes the "array with a gap" model used to store buffer
+characters.  This is based on the stuff in insdel.c and should
+probably be merged with it.  This is not extent-specific and should
+perhaps be moved into a separate file. */
+/* ------------------------------- */
+/*        internal functions       */
+/* ------------------------------- */
+/* Adjust the gap array markers in the range (FROM, TO].  Parallel to
+adjust_markers() in insdel.c. */
+static void
+gap_array_adjust_markers (Gap_Array *ga, Memind from,
+			  Memind to, int amount)
+{
+Gap_Array_Marker *m;
+for (m = ga->markers; m; m = m->next)
+m->pos = do_marker_adjustment (m->pos, from, to, amount);
+}
+/* Move the gap to array position POS.  Parallel to move_gap() in
+insdel.c but somewhat simplified. */
+static void
+gap_array_move_gap (Gap_Array *ga, int pos)
+{
+int gap = ga->gap;
+int gapsize = ga->gapsize;
+assert (ga->array);
+if (pos < gap)
+{
+memmove (GAP_ARRAY_MEMEL_ADDR (ga, pos + gapsize),
+	       GAP_ARRAY_MEMEL_ADDR (ga, pos),
+	       (gap - pos)*ga->elsize);
+gap_array_adjust_markers (ga, (Memind) pos, (Memind) gap,
+				gapsize);
+}
+else if (pos > gap)
+{
+memmove (GAP_ARRAY_MEMEL_ADDR (ga, gap),
+	       GAP_ARRAY_MEMEL_ADDR (ga, gap + gapsize),
+	       (pos - gap)*ga->elsize);
+gap_array_adjust_markers (ga, (Memind) (gap + gapsize),
+				(Memind) (pos + gapsize), - gapsize);
+}
+ga->gap = pos;
+}
+/* Make the gap INCREMENT characters longer.  Parallel to make_gap() in
+insdel.c. */
+static void
+gap_array_make_gap (Gap_Array *ga, int increment)
+{
+char *ptr = ga->array;
+int real_gap_loc;
+int old_gap_size;
+/* If we have to get more space, get enough to last a while.  We use
+a geometric progression that saves on realloc space. */
+increment += 100 + ga->numels / 8;
+ptr = (char *) xrealloc (ptr,
+			   (ga->numels + ga->gapsize + increment)*ga->elsize);
+if (ptr == 0)
+memory_full ();
+ga->array = ptr;
+real_gap_loc = ga->gap;
+old_gap_size = ga->gapsize;
+/* Call the newly allocated space a gap at the end of the whole space.  */
+ga->gap = ga->numels + ga->gapsize;
+ga->gapsize = increment;
+/* Move the new gap down to be consecutive with the end of the old one.
+This adjusts the markers properly too.  */
+gap_array_move_gap (ga, real_gap_loc + old_gap_size);
+/* Now combine the two into one large gap.  */
+ga->gapsize += old_gap_size;
+ga->gap = real_gap_loc;
+}
+/* ------------------------------- */
+/*        external functions       */
+/* ------------------------------- */
+/* Insert NUMELS elements (pointed to by ELPTR) into the specified
+gap array at POS. */
+static void
+gap_array_insert_els (Gap_Array *ga, int pos, void *elptr, int numels)
+{
+assert (pos >= 0 && pos <= ga->numels);
+if (ga->gapsize < numels)
+gap_array_make_gap (ga, numels - ga->gapsize);
+if (pos != ga->gap)
+gap_array_move_gap (ga, pos);
+memcpy (GAP_ARRAY_MEMEL_ADDR (ga, ga->gap), (char *) elptr,
+	  numels*ga->elsize);
+ga->gapsize -= numels;
+ga->gap += numels;
+ga->numels += numels;
+/* This is the equivalent of insert-before-markers.
+#### Should only happen if marker is "moves forward at insert" type.
+*/
+gap_array_adjust_markers (ga, pos - 1, pos, numels);
+}
+/* Delete NUMELS elements from the specified gap array, starting at FROM. */
+static void
+gap_array_delete_els (Gap_Array *ga, int from, int numdel)
+{
+int to = from + numdel;
+int gapsize = ga->gapsize;
+assert (from >= 0);
+assert (numdel >= 0);
+assert (to <= ga->numels);
+/* Make sure the gap is somewhere in or next to what we are deleting.  */
+if (to < ga->gap)
+gap_array_move_gap (ga, to);
+if (from > ga->gap)
+gap_array_move_gap (ga, from);
+/* Relocate all markers pointing into the new, larger gap
+to point at the end of the text before the gap.  */
+gap_array_adjust_markers (ga, to + gapsize, to + gapsize,
+			    - numdel - gapsize);
+ga->gapsize += numdel;
+ga->numels -= numdel;
+ga->gap = from;
+}
+static Gap_Array_Marker *
+gap_array_make_marker (Gap_Array *ga, int pos)
+{
+Gap_Array_Marker *m;
+assert (pos >= 0 && pos <= ga->numels);
+if (gap_array_marker_freelist)
+{
+m = gap_array_marker_freelist;
+gap_array_marker_freelist = gap_array_marker_freelist->next;
+}
+else
+m = xnew (Gap_Array_Marker);
+m->pos = GAP_ARRAY_ARRAY_TO_MEMORY_POS (ga, pos);
+m->next = ga->markers;
+ga->markers = m;
+return m;
+}
+static void
+gap_array_delete_marker (Gap_Array *ga, Gap_Array_Marker *m)
+{
+Gap_Array_Marker *p, *prev;
+for (prev = 0, p = ga->markers; p && p != m; prev = p, p = p->next)
+;
+assert (p);
+if (prev)
+prev->next = p->next;
+else
+ga->markers = p->next;
+m->next = gap_array_marker_freelist;
+m->pos = 0xDEADBEEF; /* -559038737 as an int */
+gap_array_marker_freelist = m;
+}
+static void
+gap_array_delete_all_markers (Gap_Array *ga)
+{
+Gap_Array_Marker *p, *next;
+for (p = ga->markers; p; p = next)
+{
+next = p->next;
+p->next = gap_array_marker_freelist;
+p->pos = 0xDEADBEEF; /* -559038737 as an int */
+gap_array_marker_freelist = p;
+}
+}
+static void
+gap_array_move_marker (Gap_Array *ga, Gap_Array_Marker *m, int pos)
+{
+assert (pos >= 0 && pos <= ga->numels);
+m->pos = GAP_ARRAY_ARRAY_TO_MEMORY_POS (ga, pos);
+}
+#define gap_array_marker_pos(ga, m) \
+GAP_ARRAY_MEMORY_TO_ARRAY_POS (ga, (m)->pos)
+static Gap_Array *
+make_gap_array (int elsize)
+{
+Gap_Array *ga = xnew_and_zero (Gap_Array);
+ga->elsize = elsize;
+return ga;
+}
+static void
+free_gap_array (Gap_Array *ga)
+{
+if (ga->array)
+xfree (ga->array);
+gap_array_delete_all_markers (ga);
+xfree (ga);
+}
+/************************************************************************/
+/*                       Extent list primitives                         */
+/************************************************************************/
+/* A list of extents is maintained as a double gap array: one gap array
+is ordered by start index (the "display order") and the other is
+ordered by end index (the "e-order").  Note that positions in an
+extent list should logically be conceived of as referring *to*
+a particular extent (as is the norm in programs) rather than
+sitting between two extents.  Note also that callers of these
+functions should not be aware of the fact that the extent list is
+implemented as an array, except for the fact that positions are
+integers (this should be generalized to handle integers and linked
+list equally well).
+*/
+/* Number of elements in an extent list */
+#define extent_list_num_els(el) GAP_ARRAY_NUM_ELS(el->start)
+/* Return the position at which EXTENT is located in the specified extent
+list (in the display order if ENDP is 0, in the e-order otherwise).
+If the extent is not found, the position where the extent would
+be inserted is returned.  If ENDP is 0, the insertion would go after
+all other equal extents.  If ENDP is not 0, the insertion would go
+before all other equal extents.  If FOUNDP is not 0, then whether
+the extent was found will get written into it. */
+static int
+extent_list_locate (Extent_List *el, EXTENT extent, int endp, int *foundp)
+{
+Gap_Array *ga = endp ? el->end : el->start;
+int left = 0, right = GAP_ARRAY_NUM_ELS (ga);
+int oldfoundpos, foundpos;
+int found;
+while (left != right)
+{
+/* RIGHT might not point to a valid extent (i.e. it's at the end
+	 of the list), so NEWPOS must round down. */
+unsigned int newpos = (left + right) >> 1;
+EXTENT e = EXTENT_GAP_ARRAY_AT (ga, (int) newpos);
+if (endp ? EXTENT_E_LESS (e, extent) : EXTENT_LESS (e, extent))
+	left = newpos+1;
+else
+	right = newpos;
+}
+/* Now we're at the beginning of all equal extents. */
+found = 0;
+oldfoundpos = foundpos = left;
+while (foundpos < GAP_ARRAY_NUM_ELS (ga))
+{
+EXTENT e = EXTENT_GAP_ARRAY_AT (ga, foundpos);
+if (e == extent)
+	{
+	  found = 1;
+	  break;
+	}
+if (!EXTENT_EQUAL (e, extent))
+	break;
+foundpos++;
+}
+if (foundp)
+*foundp = found;
+if (found || !endp)
+return foundpos;
+else
+return oldfoundpos;
+}
+/* Return the position of the first extent that begins at or after POS
+(or ends at or after POS, if ENDP is not 0).
+An out-of-range value for POS is allowed, and guarantees that the
+position at the beginning or end of the extent list is returned. */
+static int
+extent_list_locate_from_pos (Extent_List *el, Memind pos, int endp)
+{
+struct extent fake_extent;
+/*
+Note that if we search for [POS, POS], then we get the following:
+-- if ENDP is 0, then all extents whose start position is <= POS
+lie before the returned position, and all extents whose start
+position is > POS lie at or after the returned position.
+-- if ENDP is not 0, then all extents whose end position is < POS
+lie before the returned position, and all extents whose end
+position is >= POS lie at or after the returned position.
+*/
+set_extent_start (&fake_extent, endp ? pos : pos-1);
+set_extent_end (&fake_extent, endp ? pos : pos-1);
+return extent_list_locate (el, &fake_extent, endp, 0);
+}
+/* Return the extent at POS. */
+static EXTENT
+extent_list_at (Extent_List *el, Memind pos, int endp)
+{
+Gap_Array *ga = endp ? el->end : el->start;
+assert (pos >= 0 && pos < GAP_ARRAY_NUM_ELS (ga));
+return EXTENT_GAP_ARRAY_AT (ga, pos);
+}
+/* Insert an extent into an extent list. */
+static void
+extent_list_insert (Extent_List *el, EXTENT extent)
+{
+int pos, foundp;
+pos = extent_list_locate (el, extent, 0, &foundp);
+assert (!foundp);
+gap_array_insert_els (el->start, pos, &extent, 1);
+pos = extent_list_locate (el, extent, 1, &foundp);
+assert (!foundp);
+gap_array_insert_els (el->end, pos, &extent, 1);
+}
+/* Delete an extent from an extent list. */
+static void
+extent_list_delete (Extent_List *el, EXTENT extent)
+{
+int pos, foundp;
+pos = extent_list_locate (el, extent, 0, &foundp);
+assert (foundp);
+gap_array_delete_els (el->start, pos, 1);
+pos = extent_list_locate (el, extent, 1, &foundp);
+assert (foundp);
+gap_array_delete_els (el->end, pos, 1);
+}
+static void
+extent_list_delete_all (Extent_List *el)
+{
+gap_array_delete_els (el->start, 0, GAP_ARRAY_NUM_ELS (el->start));
+gap_array_delete_els (el->end, 0, GAP_ARRAY_NUM_ELS (el->end));
+}
+static Extent_List_Marker *
+extent_list_make_marker (Extent_List *el, int pos, int endp)
+{
+Extent_List_Marker *m;
+if (extent_list_marker_freelist)
+{
+m = extent_list_marker_freelist;
+extent_list_marker_freelist = extent_list_marker_freelist->next;
+}
+else
+m = xnew (Extent_List_Marker);
+m->m = gap_array_make_marker (endp ? el->end : el->start, pos);
+m->endp = endp;
+m->next = el->markers;
+el->markers = m;
+return m;
+}
+#define extent_list_move_marker(el, mkr, pos) \
+gap_array_move_marker((mkr)->endp ? (el)->end : (el)->start, (mkr)->m, pos)
+static void
+extent_list_delete_marker (Extent_List *el, Extent_List_Marker *m)
+{
+Extent_List_Marker *p, *prev;
+for (prev = 0, p = el->markers; p && p != m; prev = p, p = p->next)
+;
+assert (p);
+if (prev)
+prev->next = p->next;
+else
+el->markers = p->next;
+m->next = extent_list_marker_freelist;
+extent_list_marker_freelist = m;
+gap_array_delete_marker (m->endp ? el->end : el->start, m->m);
+}
+#define extent_list_marker_pos(el, mkr) \
+gap_array_marker_pos ((mkr)->endp ? (el)->end : (el)->start, (mkr)->m)
+static Extent_List *
+allocate_extent_list (void)
+{
+Extent_List *el = xnew (Extent_List);
+el->start = make_gap_array (sizeof(EXTENT));
+el->end = make_gap_array (sizeof(EXTENT));
+el->markers = 0;
+return el;
+}
+static void
+free_extent_list (Extent_List *el)
+{
+free_gap_array (el->start);
+free_gap_array (el->end);
+xfree (el);
+}
+/************************************************************************/
+/*                       Auxiliary extent structure                     */
+/************************************************************************/
+static Lisp_Object
+mark_extent_auxiliary (Lisp_Object obj)
+{
+struct extent_auxiliary *data = XEXTENT_AUXILIARY (obj);
+mark_object (data->begin_glyph);
+mark_object (data->end_glyph);
+mark_object (data->invisible);
+mark_object (data->children);
+mark_object (data->read_only);
+mark_object (data->mouse_face);
+mark_object (data->initial_redisplay_function);
+mark_object (data->before_change_functions);
+mark_object (data->after_change_functions);
+return data->parent;
+}
+DEFINE_LRECORD_IMPLEMENTATION ("extent-auxiliary", extent_auxiliary,
+mark_extent_auxiliary, internal_object_printer,
+			       0, 0, 0, 0, struct extent_auxiliary);
+void
+allocate_extent_auxiliary (EXTENT ext)
+{
+Lisp_Object extent_aux;
+struct extent_auxiliary *data =
+alloc_lcrecord_type (struct extent_auxiliary, &lrecord_extent_auxiliary);
+copy_lcrecord (data, &extent_auxiliary_defaults);
+XSETEXTENT_AUXILIARY (extent_aux, data);
+ext->plist = Fcons (extent_aux, ext->plist);
+ext->flags.has_aux = 1;
+}
+/************************************************************************/
+/*                         Extent info structure                        */
+/************************************************************************/
+/* An extent-info structure consists of a list of the buffer or string's
+extents and a "stack of extents" that lists all of the extents over
+a particular position.  The stack-of-extents info is used for
+optimization purposes -- it basically caches some info that might
+be expensive to compute.  Certain otherwise hard computations are easy
+given the stack of extents over a particular position, and if the
+stack of extents over a nearby position is known (because it was
+calculated at some prior point in time), it's easy to move the stack
+of extents to the proper position.
+Given that the stack of extents is an optimization, and given that
+it requires memory, a string's stack of extents is wiped out each
+time a garbage collection occurs.  Therefore, any time you retrieve
+the stack of extents, it might not be there.  If you need it to
+be there, use the _force version.
+Similarly, a string may or may not have an extent_info structure.
+(Generally it won't if there haven't been any extents added to the
+string.) So use the _force version if you need the extent_info
+structure to be there. */
+static struct stack_of_extents *allocate_soe (void);
+static void free_soe (struct stack_of_extents *soe);
+static void soe_invalidate (Lisp_Object obj);
+static Lisp_Object
+mark_extent_info (Lisp_Object obj)
+{
+struct extent_info *data = (struct extent_info *) XEXTENT_INFO (obj);
+int i;
+Extent_List *list = data->extents;
+/* Vbuffer_defaults and Vbuffer_local_symbols are buffer-like
+objects that are created specially and never have their extent
+list initialized (or rather, it is set to zero in
+nuke_all_buffer_slots()).  However, these objects get
+garbage-collected so we have to deal.
+(Also the list can be zero when we're dealing with a destroyed
+buffer.) */
+if (list)
+{
+for (i = 0; i < extent_list_num_els (list); i++)
+	{
+	  struct extent *extent = extent_list_at (list, i, 0);
+	  Lisp_Object exobj;
+	  XSETEXTENT (exobj, extent);
+	  mark_object (exobj);
+	}
+}
+return Qnil;
+}
+static void
+finalize_extent_info (void *header, int for_disksave)
+{
+struct extent_info *data = (struct extent_info *) header;
+if (for_disksave)
+return;
+if (data->soe)
+{
+free_soe (data->soe);
+data->soe = 0;
+}
+if (data->extents)
+{
+free_extent_list (data->extents);
+data->extents = 0;
+}
+}
+DEFINE_LRECORD_IMPLEMENTATION ("extent-info", extent_info,
+mark_extent_info, internal_object_printer,
+			       finalize_extent_info, 0, 0, 0,
+			       struct extent_info);
+static Lisp_Object
+allocate_extent_info (void)
+{
+Lisp_Object extent_info;
+struct extent_info *data =
+alloc_lcrecord_type (struct extent_info, &lrecord_extent_info);
+XSETEXTENT_INFO (extent_info, data);
+data->extents = allocate_extent_list ();
+data->soe = 0;
+return extent_info;
+}
+void
+flush_cached_extent_info (Lisp_Object extent_info)
+{
+struct extent_info *data = XEXTENT_INFO (extent_info);
+if (data->soe)
+{
+free_soe (data->soe);
+data->soe = 0;
+}
+}
+/************************************************************************/
+/*                    Buffer/string extent primitives                   */
+/************************************************************************/
+/* The functions in this section are the ONLY ones that should know
+about the internal implementation of the extent lists.  Other functions
+should only know that there are two orderings on extents, the "display"
+order (sorted by start position, basically) and the e-order (sorted
+by end position, basically), and that certain operations are provided
+to manipulate the list. */
+/* ------------------------------- */
+/*        basic primitives         */
+/* ------------------------------- */
+static Lisp_Object
+decode_buffer_or_string (Lisp_Object object)
+{
+if (NILP (object))
+XSETBUFFER (object, current_buffer);
+else if (BUFFERP (object))
+CHECK_LIVE_BUFFER (object);
+else if (STRINGP (object))
+;
+else
+dead_wrong_type_argument (Qbuffer_or_string_p, object);
+return object;
+}
+EXTENT
+extent_ancestor_1 (EXTENT e)
+{
+while (e->flags.has_parent)
+{
+/* There should be no circularities except in case of a logic
+	 error somewhere in the extent code */
+e = XEXTENT (XEXTENT_AUXILIARY (XCAR (e->plist))->parent);
+}
+return e;
+}
+/* Given an extent object (string or buffer or nil), return its extent info.
+This may be 0 for a string. */
+static struct extent_info *
+buffer_or_string_extent_info (Lisp_Object object)
+{
+if (STRINGP (object))
+{
+Lisp_Object plist = XSTRING (object)->plist;
+if (!CONSP (plist) || !EXTENT_INFOP (XCAR (plist)))
+	return 0;
+return XEXTENT_INFO (XCAR (plist));
+}
+else if (NILP (object))
+return 0;
+else
+return XEXTENT_INFO (XBUFFER (object)->extent_info);
+}
+/* Given a string or buffer, return its extent list.  This may be
+0 for a string. */
+static Extent_List *
+buffer_or_string_extent_list (Lisp_Object object)
+{
+struct extent_info *info = buffer_or_string_extent_info (object);
+if (!info)
+return 0;
+return info->extents;
+}
+/* Given a string or buffer, return its extent info.  If it's not there,
+create it. */
+static struct extent_info *
+buffer_or_string_extent_info_force (Lisp_Object object)
+{
+struct extent_info *info = buffer_or_string_extent_info (object);
+if (!info)
+{
+Lisp_Object extent_info;
+assert (STRINGP (object)); /* should never happen for buffers --
+				    the only buffers without an extent
+				    info are those after finalization,
+				    destroyed buffers, or special
+				    Lisp-inaccessible buffer objects. */
+extent_info = allocate_extent_info ();
+XSTRING (object)->plist = Fcons (extent_info, XSTRING (object)->plist);
+return XEXTENT_INFO (extent_info);
+}
+return info;
+}
+/* Detach all the extents in OBJECT.  Called from redisplay. */
+void
+detach_all_extents (Lisp_Object object)
+{
+struct extent_info *data = buffer_or_string_extent_info (object);
+if (data)
+{
+if (data->extents)
+	{
+	  int i;
+	  for (i = 0; i < extent_list_num_els (data->extents); i++)
+	    {
+	      EXTENT e = extent_list_at (data->extents, i, 0);
+	      /* No need to do detach_extent().  Just nuke the damn things,
+		 which results in the equivalent but faster. */
+	      set_extent_start (e, -1);
+	      set_extent_end (e, -1);
+	    }
+	}
+/* But we need to clear all the lists containing extents or
+	 havoc will result. */
+extent_list_delete_all (data->extents);
+soe_invalidate (object);
+}
+}
+void
+init_buffer_extents (struct buffer *b)
+{
+b->extent_info = allocate_extent_info ();
+}
+void
+uninit_buffer_extents (struct buffer *b)
+{
+struct extent_info *data = XEXTENT_INFO (b->extent_info);
+/* Don't destroy the extents here -- there may still be children
+extents pointing to the extents. */
+detach_all_extents (make_buffer (b));
+finalize_extent_info (data, 0);
+}
+/* Retrieve the extent list that an extent is a member of; the
+return value will never be 0 except in destroyed buffers (in which
+case the only extents that can refer to this buffer are detached
+ones). */
+#define extent_extent_list(e) buffer_or_string_extent_list (extent_object (e))
+/* ------------------------------- */
+/*        stack of extents         */
+/* ------------------------------- */
+#ifdef ERROR_CHECK_EXTENTS
+void
+sledgehammer_extent_check (Lisp_Object object)
+{
+int i;
+int endp;
+Extent_List *el = buffer_or_string_extent_list (object);
+struct buffer *buf = 0;
+if (!el)
+return;
+if (BUFFERP (object))
+buf = XBUFFER (object);
+for (endp = 0; endp < 2; endp++)
+for (i = 1; i < extent_list_num_els (el); i++)
+{
+EXTENT e1 = extent_list_at (el, i-1, endp);
+	EXTENT e2 = extent_list_at (el, i, endp);
+	if (buf)
+	  {
+	    assert (extent_start (e1) <= buf->text->gpt ||
+		    extent_start (e1) > buf->text->gpt + buf->text->gap_size);
+	    assert (extent_end (e1) <= buf->text->gpt ||
+		    extent_end (e1) > buf->text->gpt + buf->text->gap_size);
+	  }
+	assert (extent_start (e1) <= extent_end (e1));
+	assert (endp ? (EXTENT_E_LESS_EQUAL (e1, e2)) :
+		       (EXTENT_LESS_EQUAL (e1, e2)));
+}
+}
+#endif
+static Stack_Of_Extents *
+buffer_or_string_stack_of_extents (Lisp_Object object)
+{
+struct extent_info *info = buffer_or_string_extent_info (object);
+if (!info)
+return 0;
+return info->soe;
+}
+static Stack_Of_Extents *
+buffer_or_string_stack_of_extents_force (Lisp_Object object)
+{
+struct extent_info *info = buffer_or_string_extent_info_force (object);
+if (!info->soe)
+info->soe = allocate_soe ();
+return info->soe;
+}
+/* #define SOE_DEBUG */
+#ifdef SOE_DEBUG
+static void print_extent_1 (char *buf, Lisp_Object extent);
+static void
+print_extent_2 (EXTENT e)
+{
+Lisp_Object extent;
+char buf[200];
+XSETEXTENT (extent, e);
+print_extent_1 (buf, extent);
+fputs (buf, stdout);
+}
+static void
+soe_dump (Lisp_Object obj)
+{
+int i;
+Stack_Of_Extents *soe = buffer_or_string_stack_of_extents (obj);
+Extent_List *sel;
+int endp;
+if (!soe)
+{
+printf ("No SOE");
+return;
+}
+sel = soe->extents;
+printf ("SOE pos is %d (memind %d)\n",
+	  soe->pos < 0 ? soe->pos :
+	  buffer_or_string_memind_to_bytind (obj, soe->pos),
+	  soe->pos);
+for (endp = 0; endp < 2; endp++)
+{
+printf (endp ? "SOE end:" : "SOE start:");
+for (i = 0; i < extent_list_num_els (sel); i++)
+	{
+	  EXTENT e = extent_list_at (sel, i, endp);
+	  putchar ('\t');
+	  print_extent_2 (e);
+	}
+putchar ('\n');
+}
+putchar ('\n');
+}
+#endif
+/* Insert EXTENT into OBJ's stack of extents, if necessary. */
+static void
+soe_insert (Lisp_Object obj, EXTENT extent)
+{
+Stack_Of_Extents *soe = buffer_or_string_stack_of_extents (obj);
+#ifdef SOE_DEBUG
+printf ("Inserting into SOE: ");
+print_extent_2 (extent);
+putchar ('\n');
+#endif
+if (!soe || soe->pos < extent_start (extent) ||
+soe->pos > extent_end (extent))
+{
+#ifdef SOE_DEBUG
+printf ("(not needed)\n\n");
+#endif
+return;
+}
+extent_list_insert (soe->extents, extent);
+#ifdef SOE_DEBUG
+puts ("SOE afterwards is:");
+soe_dump (obj);
+#endif
+}
+/* Delete EXTENT from OBJ's stack of extents, if necessary. */
+static void
+soe_delete (Lisp_Object obj, EXTENT extent)
+{
+Stack_Of_Extents *soe = buffer_or_string_stack_of_extents (obj);
+#ifdef SOE_DEBUG
+printf ("Deleting from SOE: ");
+print_extent_2 (extent);
+putchar ('\n');
+#endif
+if (!soe || soe->pos < extent_start (extent) ||
+soe->pos > extent_end (extent))
+{
+#ifdef SOE_DEBUG
+puts ("(not needed)\n");
+#endif
+return;
+}
+extent_list_delete (soe->extents, extent);
+#ifdef SOE_DEBUG
+puts ("SOE afterwards is:");
+soe_dump (obj);
+#endif
+}
+/* Move OBJ's stack of extents to lie over the specified position. */
+static void
+soe_move (Lisp_Object obj, Memind pos)
+{
+Stack_Of_Extents *soe = buffer_or_string_stack_of_extents_force (obj);
+Extent_List *sel = soe->extents;
+int numsoe = extent_list_num_els (sel);
+Extent_List *bel = buffer_or_string_extent_list (obj);
+int direction;
+int endp;
+#ifdef ERROR_CHECK_EXTENTS
+assert (bel);
+#endif
+#ifdef SOE_DEBUG
+printf ("Moving SOE from %d (memind %d) to %d (memind %d)\n",
+	  soe->pos < 0 ? soe->pos :
+	  buffer_or_string_memind_to_bytind (obj, soe->pos), soe->pos,
+	  buffer_or_string_memind_to_bytind (obj, pos), pos);
+#endif
+if (soe->pos < pos)
+{
+direction = 1;
+endp = 0;
+}
+else if (soe->pos > pos)
+{
+direction = -1;
+endp = 1;
+}
+else
+{
+#ifdef SOE_DEBUG
+puts ("(not needed)\n");
+#endif
+return;
+}
+/* For DIRECTION = 1: Any extent that overlaps POS is either in the
+SOE (if the extent starts at or before SOE->POS) or is greater
+(in the display order) than any extent in the SOE (if it starts
+after SOE->POS).
+For DIRECTION = -1: Any extent that overlaps POS is either in the
+SOE (if the extent ends at or after SOE->POS) or is less (in the
+e-order) than any extent in the SOE (if it ends before SOE->POS).
+We proceed in two stages:
+1) delete all extents in the SOE that don't overlap POS.
+2) insert all extents into the SOE that start (or end, when
+DIRECTION = -1) in (SOE->POS, POS] and that overlap
+	POS. (Don't include SOE->POS in the range because those
+	extents would already be in the SOE.)
+*/
+/* STAGE 1. */
+if (numsoe > 0)
+{
+/* Delete all extents in the SOE that don't overlap POS.
+	 This is all extents that end before (or start after,
+	 if DIRECTION = -1) POS.
+*/
+/* Deleting extents from the SOE is tricky because it changes
+	 the positions of extents.  If we are deleting in the forward
+	 direction we have to call extent_list_at() on the same position
+	 over and over again because positions after the deleted element
+	 get shifted back by 1.  To make life simplest, we delete forward
+	 irrespective of DIRECTION.
+*/
+int start, end;
+int i;
+if (direction > 0)
+	{
+	  start = 0;
+	  end = extent_list_locate_from_pos (sel, pos, 1);
+	}
+else
+	{
+	  start = extent_list_locate_from_pos (sel, pos+1, 0);
+	  end = numsoe;
+	}
+for (i = start; i < end; i++)
+	extent_list_delete (sel, extent_list_at (sel, start /* see above */,
+						 !endp));
+}
+/* STAGE 2. */
+{
+int start_pos;
+if (direction < 0)
+start_pos = extent_list_locate_from_pos (bel, soe->pos, endp) - 1;
+else
+start_pos = extent_list_locate_from_pos (bel, soe->pos + 1, endp);
+for (; start_pos >= 0 && start_pos < extent_list_num_els (bel);
+	 start_pos += direction)
+{
+	EXTENT e = extent_list_at (bel, start_pos, endp);
+	if ((direction > 0) ?
+	    (extent_start (e) > pos) :
+	    (extent_end (e) < pos))
+	  break; /* All further extents lie on the far side of POS
+		    and thus can't overlap. */
+	if ((direction > 0) ?
+	    (extent_end (e) >= pos) :
+	    (extent_start (e) <= pos))
+	  extent_list_insert (sel, e);
+}
+}
+soe->pos = pos;
+#ifdef SOE_DEBUG
+puts ("SOE afterwards is:");
+soe_dump (obj);
+#endif
+}
+static void
+soe_invalidate (Lisp_Object obj)
+{
+Stack_Of_Extents *soe = buffer_or_string_stack_of_extents (obj);
+if (soe)
+{
+extent_list_delete_all (soe->extents);
+soe->pos = -1;
+}
+}
+static struct stack_of_extents *
+allocate_soe (void)
+{
+struct stack_of_extents *soe = xnew_and_zero (struct stack_of_extents);
+soe->extents = allocate_extent_list ();
+soe->pos = -1;
+return soe;
+}
+static void
+free_soe (struct stack_of_extents *soe)
+{
+free_extent_list (soe->extents);
+xfree (soe);
+}
+/* ------------------------------- */
+/*        other primitives         */
+/* ------------------------------- */
+/* Return the start (endp == 0) or end (endp == 1) of an extent as
+a byte index.  If you want the value as a memory index, use
+extent_endpoint().  If you want the value as a buffer position,
+use extent_endpoint_bufpos(). */
+static Bytind
+extent_endpoint_bytind (EXTENT extent, int endp)
+{
+assert (EXTENT_LIVE_P (extent));
+assert (!extent_detached_p (extent));
+{
+Memind i = (endp) ? (extent_end (extent)) :
+(extent_start (extent));
+Lisp_Object obj = extent_object (extent);
+return buffer_or_string_memind_to_bytind (obj, i);
+}
+}
+static Bufpos
+extent_endpoint_bufpos (EXTENT extent, int endp)
+{
+assert (EXTENT_LIVE_P (extent));
+assert (!extent_detached_p (extent));
+{
+Memind i = (endp) ? (extent_end (extent)) :
+(extent_start (extent));
+Lisp_Object obj = extent_object (extent);
+return buffer_or_string_memind_to_bufpos (obj, i);
+}
+}
+/* A change to an extent occurred that will change the display, so
+notify redisplay.  Maybe also recurse over all the extent's
+descendants. */
+static void
+extent_changed_for_redisplay (EXTENT extent, int descendants_too,
+			      int invisibility_change)
+{
+Lisp_Object object;
+Lisp_Object rest;
+/* we could easily encounter a detached extent while traversing the
+children, but we should never be able to encounter a dead extent. */
+assert (EXTENT_LIVE_P (extent));
+if (descendants_too)
+{
+Lisp_Object children = extent_children (extent);
+if (!NILP (children))
+	{
+	  /* first mark all of the extent's children.  We will lose big-time
+	     if there are any circularities here, so we sure as hell better
+	     ensure that there aren't. */
+	  LIST_LOOP (rest, XWEAK_LIST_LIST (children))
+	    extent_changed_for_redisplay (XEXTENT (XCAR (rest)), 1,
+					  invisibility_change);
+	}
+}
+/* now mark the extent itself. */
+object = extent_object (extent);
+if (!BUFFERP (object) || extent_detached_p (extent))
+/* #### Can changes to string extents affect redisplay?
+I will have to think about this.  What about string glyphs?
+Things in the modeline? etc. */
+/* #### changes to string extents can certainly affect redisplay
+if the extent is in some generated-modeline-string: when
+we change an extent in generated-modeline-string, this changes
+its parent, which is in `modeline-format', so we should
+force the modeline to be updated.  But how to determine whether
+a string is a `generated-modeline-string'?  Looping through
+all buffers is not very efficient.  Should we add all
+`generated-modeline-string' strings to a hash table?
+Maybe efficiency is not the greatest concern here and there's
+no big loss in looping over the buffers. */
+return;
+{
+struct buffer *b;
+b = XBUFFER (object);
+BUF_FACECHANGE (b)++;
+MARK_EXTENTS_CHANGED;
+if (invisibility_change)
+MARK_CLIP_CHANGED;
+buffer_extent_signal_changed_region (b,
+					 extent_endpoint_bufpos (extent, 0),
+					 extent_endpoint_bufpos (extent, 1));
+}
+}
+/* A change to an extent occurred that might affect redisplay.
+This is called when properties such as the endpoints, the layout,
+or the priority changes.  Redisplay will be affected only if
+the extent has any displayable attributes. */
+static void
+extent_maybe_changed_for_redisplay (EXTENT extent, int descendants_too,
+				    int invisibility_change)
+{
+/* Retrieve the ancestor for efficiency */
+EXTENT anc = extent_ancestor (extent);
+if (!NILP (extent_face        (anc)) ||
+!NILP (extent_begin_glyph (anc)) ||
+!NILP (extent_end_glyph   (anc)) ||
+!NILP (extent_mouse_face  (anc)) ||
+!NILP (extent_invisible   (anc)) ||
+!NILP (extent_initial_redisplay_function (anc)) ||
+invisibility_change)
+extent_changed_for_redisplay (extent, descendants_too,
+				  invisibility_change);
+}
+static EXTENT
+make_extent_detached (Lisp_Object object)
+{
+EXTENT extent = allocate_extent ();
+assert (NILP (object) || STRINGP (object) ||
+	  (BUFFERP (object) && BUFFER_LIVE_P (XBUFFER (object))));
+extent_object (extent) = object;
+/* Now make sure the extent info exists. */
+if (!NILP (object))
+buffer_or_string_extent_info_force (object);
+return extent;
+}
+/* A "real" extent is any extent other than the internal (not-user-visible)
+extents used by `map-extents'. */
+static EXTENT
+real_extent_at_forward (Extent_List *el, int pos, int endp)
+{
+for (; pos < extent_list_num_els (el); pos++)
+{
+EXTENT e = extent_list_at (el, pos, endp);
+if (!extent_internal_p (e))
+	return e;
+}
+return 0;
+}
+static EXTENT
+real_extent_at_backward (Extent_List *el, int pos, int endp)
+{
+for (; pos >= 0; pos--)
+{
+EXTENT e = extent_list_at (el, pos, endp);
+if (!extent_internal_p (e))
+	return e;
+}
+return 0;
+}
+static EXTENT
+extent_first (Lisp_Object obj)
+{
+Extent_List *el = buffer_or_string_extent_list (obj);
+if (!el)
+return 0;
+return real_extent_at_forward (el, 0, 0);
+}
+#ifdef DEBUG_XEMACS
+static EXTENT
+extent_e_first (Lisp_Object obj)
+{
+Extent_List *el = buffer_or_string_extent_list (obj);
+if (!el)
+return 0;
+return real_extent_at_forward (el, 0, 1);
+}
+#endif
+static EXTENT
+extent_next (EXTENT e)
+{
+Extent_List *el = extent_extent_list (e);
+int foundp;
+int pos = extent_list_locate (el, e, 0, &foundp);
+assert (foundp);
+return real_extent_at_forward (el, pos+1, 0);
+}
+#ifdef DEBUG_XEMACS
+static EXTENT
+extent_e_next (EXTENT e)
+{
+Extent_List *el = extent_extent_list (e);
+int foundp;
+int pos = extent_list_locate (el, e, 1, &foundp);
+assert (foundp);
+return real_extent_at_forward (el, pos+1, 1);
+}
+#endif
+static EXTENT
+extent_last (Lisp_Object obj)
+{
+Extent_List *el = buffer_or_string_extent_list (obj);
+if (!el)
+return 0;
+return real_extent_at_backward (el, extent_list_num_els (el) - 1, 0);
+}
+#ifdef DEBUG_XEMACS
+static EXTENT
+extent_e_last (Lisp_Object obj)
+{
+Extent_List *el = buffer_or_string_extent_list (obj);
+if (!el)
+return 0;
+return real_extent_at_backward (el, extent_list_num_els (el) - 1, 1);
+}
+#endif
+static EXTENT
+extent_previous (EXTENT e)
+{
+Extent_List *el = extent_extent_list (e);
+int foundp;
+int pos = extent_list_locate (el, e, 0, &foundp);
+assert (foundp);
+return real_extent_at_backward (el, pos-1, 0);
+}
+#ifdef DEBUG_XEMACS
+static EXTENT
+extent_e_previous (EXTENT e)
+{
+Extent_List *el = extent_extent_list (e);
+int foundp;
+int pos = extent_list_locate (el, e, 1, &foundp);
+assert (foundp);
+return real_extent_at_backward (el, pos-1, 1);
+}
+#endif
+static void
+extent_attach (EXTENT extent)
+{
+Extent_List *el = extent_extent_list (extent);
+extent_list_insert (el, extent);
+soe_insert (extent_object (extent), extent);
+/* only this extent changed */
+extent_maybe_changed_for_redisplay (extent, 0,
+				      !NILP (extent_invisible (extent)));
+}
+static void
+extent_detach (EXTENT extent)
+{
+Extent_List *el;
+if (extent_detached_p (extent))
+return;
+el = extent_extent_list (extent);
+/* call this before messing with the extent. */
+extent_maybe_changed_for_redisplay (extent, 0,
+				      !NILP (extent_invisible (extent)));
+extent_list_delete (el, extent);
+soe_delete (extent_object (extent), extent);
+set_extent_start (extent, -1);
+set_extent_end (extent, -1);
+}
+/* ------------------------------- */
+/*        map-extents et al.       */
+/* ------------------------------- */
+/* Returns true iff map_extents() would visit the given extent.
+See the comments at map_extents() for info on the overlap rule.
+Assumes that all validation on the extent and buffer positions has
+already been performed (see Fextent_in_region_p ()).
+*/
+static int
+extent_in_region_p (EXTENT extent, Bytind from, Bytind to,
+		    unsigned int flags)
+{
+Lisp_Object obj = extent_object (extent);
+Endpoint_Index start, end, exs, exe;
+int start_open, end_open;
+unsigned int all_extents_flags = flags & ME_ALL_EXTENTS_MASK;
+unsigned int in_region_flags   = flags & ME_IN_REGION_MASK;
+int retval;
+/* A zero-length region is treated as closed-closed. */
+if (from == to)
+{
+flags |= ME_END_CLOSED;
+flags &= ~ME_START_OPEN;
+}
+/* So is a zero-length extent. */
+if (extent_start (extent) == extent_end (extent))
+start_open = 0, end_open = 0;
+/* `all_extents_flags' will almost always be zero. */
+else if (all_extents_flags == 0)
+{
+start_open = extent_start_open_p (extent);
+end_open   = extent_end_open_p   (extent);
+}
+else
+switch (all_extents_flags)
+{
+case ME_ALL_EXTENTS_CLOSED:      start_open = 0, end_open = 0; break;
+case ME_ALL_EXTENTS_OPEN:        start_open = 1, end_open = 1; break;
+case ME_ALL_EXTENTS_CLOSED_OPEN: start_open = 0, end_open = 1; break;
+case ME_ALL_EXTENTS_OPEN_CLOSED: start_open = 1, end_open = 0; break;
+default: abort(); break;
+}
+start = buffer_or_string_bytind_to_startind (obj, from,
+					       flags & ME_START_OPEN);
+end = buffer_or_string_bytind_to_endind (obj, to, ! (flags & ME_END_CLOSED));
+exs = memind_to_startind (extent_start (extent), start_open);
+exe = memind_to_endind   (extent_end   (extent), end_open);
+/* It's easy to determine whether an extent lies *outside* the
+region -- just determine whether it's completely before
+or completely after the region.  Reject all such extents, so
+we're now left with only the extents that overlap the region.
+*/
+if (exs > end || exe < start)
+return 0;
+/* See if any further restrictions are called for. */
+/* in_region_flags will almost always be zero. */
+if (in_region_flags == 0)
+retval = 1;
+else
+switch (in_region_flags)
+{
+case ME_START_IN_REGION:
+	retval = start <= exs && exs <= end; break;
+case ME_END_IN_REGION:
+	retval = start <= exe && exe <= end; break;
+case ME_START_AND_END_IN_REGION:
+	retval = start <= exs && exe <= end; break;
+case ME_START_OR_END_IN_REGION:
+	retval = (start <= exs && exs <= end) || (start <= exe && exe <= end);
+	break;
+default:
+	abort(); break;
+}
+return flags & ME_NEGATE_IN_REGION ? !retval : retval;
+}
+struct map_extents_struct
+{
+Extent_List *el;
+Extent_List_Marker *mkr;
+EXTENT range;
+};
+static Lisp_Object
+map_extents_unwind (Lisp_Object obj)
+{
+struct map_extents_struct *closure =
+(struct map_extents_struct *) get_opaque_ptr (obj);
+free_opaque_ptr (obj);
+if (closure->range)
+extent_detach (closure->range);
+if (closure->mkr)
+extent_list_delete_marker (closure->el, closure->mkr);
+return Qnil;
+}
+/* This is the guts of `map-extents' and the other functions that
+map over extents.  In theory the operation of this function is
+simple: just figure out what extents we're mapping over, and
+call the function on each one of them in the range.  Unfortunately
+there are a wide variety of things that the mapping function
+might do, and we have to be very tricky to avoid getting messed
+up.  Furthermore, this function needs to be very fast (it is
+called multiple times every time text is inserted or deleted
+from a buffer), and so we can't always afford the overhead of
+dealing with all the possible things that the mapping function
+might do; thus, there are many flags that can be specified
+indicating what the mapping function might or might not do.
+The result of all this is that this is the most complicated
+function in this file.  Change it at your own risk!
+A potential simplification to the logic below is to determine
+all the extents that the mapping function should be called on
+before any calls are actually made and save them in an array.
+That introduces its own complications, however (the array
+needs to be marked for garbage-collection, and a static array
+cannot be used because map_extents() needs to be reentrant).
+Furthermore, the results might be a little less sensible than
+the logic below. */
+static void
+map_extents_bytind (Bytind from, Bytind to, map_extents_fun fn, void *arg,
+		    Lisp_Object obj, EXTENT after, unsigned int flags)
+{
+Memind st, en; /* range we're mapping over */
+EXTENT range = 0; /* extent for this, if ME_MIGHT_MODIFY_TEXT */
+Extent_List *el = 0; /* extent list we're iterating over */
+Extent_List_Marker *posm = 0; /* marker for extent list,
+				   if ME_MIGHT_MODIFY_EXTENTS */
+/* count and struct for unwind-protect, if ME_MIGHT_THROW */
+int count = 0;
+struct map_extents_struct closure;
+#ifdef ERROR_CHECK_EXTENTS
+assert (from <= to);
+assert (from >= buffer_or_string_absolute_begin_byte (obj) &&
+	  from <= buffer_or_string_absolute_end_byte (obj) &&
+	  to >= buffer_or_string_absolute_begin_byte (obj) &&
+	  to <= buffer_or_string_absolute_end_byte (obj));
+#endif
+if (after)
+{
+assert (EQ (obj, extent_object (after)));
+assert (!extent_detached_p (after));
+}
+el = buffer_or_string_extent_list (obj);
+if (!el || !extent_list_num_els(el))
+return;
+el = 0;
+st = buffer_or_string_bytind_to_memind (obj, from);
+en = buffer_or_string_bytind_to_memind (obj, to);
+if (flags & ME_MIGHT_MODIFY_TEXT)
+{
+/* The mapping function might change the text in the buffer,
+	 so make an internal extent to hold the range we're mapping
+	 over. */
+range = make_extent_detached (obj);
+set_extent_start (range, st);
+set_extent_end (range, en);
+range->flags.start_open = flags & ME_START_OPEN;
+range->flags.end_open = !(flags & ME_END_CLOSED);
+range->flags.internal = 1;
+range->flags.detachable = 0;
+extent_attach (range);
+}
+if (flags & ME_MIGHT_THROW)
+{
+/* The mapping function might throw past us so we need to use an
+	 unwind_protect() to eliminate the internal extent and range
+	 that we use. */
+count = specpdl_depth ();
+closure.range = range;
+closure.mkr = 0;
+record_unwind_protect (map_extents_unwind,
+			     make_opaque_ptr (&closure));
+}
+/* ---------- Figure out where we start and what direction
+we move in.  This is the trickiest part of this
+		function. ---------- */
+/* If ME_START_IN_REGION, ME_END_IN_REGION or ME_START_AND_END_IN_REGION
+was specified and ME_NEGATE_IN_REGION was not specified, our job
+is simple because of the presence of the display order and e-order.
+(Note that theoretically do something similar for
+ME_START_OR_END_IN_REGION, but that would require more trickiness
+than it's worth to avoid hitting the same extent twice.)
+In the general case, all the extents that overlap a range can be
+divided into two classes: those whose start position lies within
+the range (including the range's end but not including the
+range's start), and those that overlap the start position,
+i.e. those in the SOE for the start position.  Or equivalently,
+the extents can be divided into those whose end position lies
+within the range and those in the SOE for the end position.  Note
+that for this purpose we treat both the range and all extents in
+the buffer as closed on both ends.  If this is not what the ME_
+flags specified, then we've mapped over a few too many extents,
+but no big deal because extent_in_region_p() will filter them
+out.   Ideally, we could move the SOE to the closer of the range's
+two ends and work forwards or backwards from there.  However, in
+order to make the semantics of the AFTER argument work out, we
+have to always go in the same direction; so we choose to always
+move the SOE to the start position.
+When it comes time to do the SOE stage, we first call soe_move()
+so that the SOE gets set up.  Note that the SOE might get
+changed while we are mapping over its contents.  If we can
+guarantee that the SOE won't get moved to a new position, we
+simply need to put a marker in the SOE and we will track deletions
+and insertions of extents in the SOE.  If the SOE might get moved,
+however (this would happen as a result of a recursive invocation
+of map-extents or a call to a redisplay-type function), then
+trying to track its changes is hopeless, so we just keep a
+marker to the first (or last) extent in the SOE and use that as
+our bound.
+Finally, if DONT_USE_SOE is defined, we don't use the SOE at all
+and instead just map from the beginning of the buffer.  This is
+used for testing purposes and allows the SOE to be calculated
+using map_extents() instead of the other way around. */
+{
+int range_flag; /* ME_*_IN_REGION subset of flags */
+int do_soe_stage = 0; /* Are we mapping over the SOE? */
+/* Does the range stage map over start or end positions? */
+int range_endp;
+/* If type == 0, we include the start position in the range stage mapping.
+If type == 1, we exclude the start position in the range stage mapping.
+If type == 2, we begin at range_start_pos, an extent-list position.
+*/
+int range_start_type = 0;
+int range_start_pos = 0;
+int stage;
+range_flag = flags & ME_IN_REGION_MASK;
+if ((range_flag == ME_START_IN_REGION ||
+	 range_flag == ME_START_AND_END_IN_REGION) &&
+	!(flags & ME_NEGATE_IN_REGION))
+{
+	/* map over start position in [range-start, range-end].  No SOE
+	   stage. */
+	range_endp = 0;
+}
+else if (range_flag == ME_END_IN_REGION && !(flags & ME_NEGATE_IN_REGION))
+{
+	/* map over end position in [range-start, range-end].  No SOE
+	   stage. */
+	range_endp = 1;
+}
+else
+{
+	/* Need to include the SOE extents. */
+#ifdef DONT_USE_SOE
+	/* Just brute-force it: start from the beginning. */
+	range_endp = 0;
+	range_start_type = 2;
+	range_start_pos = 0;
+#else
+	Stack_Of_Extents *soe = buffer_or_string_stack_of_extents_force (obj);
+	int numsoe;
+	/* Move the SOE to the closer end of the range.  This dictates
+	   whether we map over start positions or end positions. */
+	range_endp = 0;
+	soe_move (obj, st);
+	numsoe = extent_list_num_els (soe->extents);
+	if (numsoe)
+	  {
+	    if (flags & ME_MIGHT_MOVE_SOE)
+	      {
+		int foundp;
+		/* Can't map over SOE, so just extend range to cover the
+		   SOE. */
+		EXTENT e = extent_list_at (soe->extents, 0, 0);
+		range_start_pos =
+		  extent_list_locate (buffer_or_string_extent_list (obj), e, 0,
+				      &foundp);
+		assert (foundp);
+		range_start_type = 2;
+	      }
+	    else
+	      {
+		/* We can map over the SOE. */
+		do_soe_stage = 1;
+		range_start_type = 1;
+	      }
+	  }
+	else
+	  {
+	    /* No extents in the SOE to map over, so we act just as if
+	       ME_START_IN_REGION or ME_END_IN_REGION was specified.
+	       RANGE_ENDP already specified so no need to do anything else. */
+	  }
+}
+#endif
+/* ---------- Now loop over the extents. ---------- */
+/* We combine the code for the two stages because much of it
+overlaps. */
+for (stage = 0; stage < 2; stage++)
+{
+	int pos = 0; /* Position in extent list */
+	/* First set up start conditions */
+	if (stage == 0)
+	  { /* The SOE stage */
+	    if (!do_soe_stage)
+	      continue;
+	    el = buffer_or_string_stack_of_extents_force (obj)->extents;
+	    /* We will always be looping over start extents here. */
+	    assert (!range_endp);
+	    pos = 0;
+	  }
+	else
+	  { /* The range stage */
+	    el = buffer_or_string_extent_list (obj);
+	    switch (range_start_type)
+	      {
+	      case 0:
+		pos = extent_list_locate_from_pos (el, st, range_endp);
+		break;
+	      case 1:
+		pos = extent_list_locate_from_pos (el, st + 1, range_endp);
+		break;
+	      case 2:
+		pos = range_start_pos;
+		break;
+	      }
+	  }
+	if (flags & ME_MIGHT_MODIFY_EXTENTS)
+	  {
+	    /* Create a marker to track changes to the extent list */
+	    if (posm)
+	      /* Delete the marker used in the SOE stage. */
+	      extent_list_delete_marker
+		(buffer_or_string_stack_of_extents_force (obj)->extents, posm);
+	    posm = extent_list_make_marker (el, pos, range_endp);
+	    /* tell the unwind function about the marker. */
+	    closure.el = el;
+	    closure.mkr = posm;
+	  }
+	/* Now loop! */
+	for (;;)
+	  {
+	    EXTENT e;
+	    Lisp_Object obj2;
+	    /* ----- update position in extent list
+	             and fetch next extent ----- */
+	    if (posm)
+	      /* fetch POS again to track extent insertions or deletions */
+	      pos = extent_list_marker_pos (el, posm);
+	    if (pos >= extent_list_num_els (el))
+	      break;
+	    e = extent_list_at (el, pos, range_endp);
+	    pos++;
+	    if (posm)
+	      /* now point the marker to the next one we're going to process.
+		 This ensures graceful behavior if this extent is deleted. */
+	      extent_list_move_marker (el, posm, pos);
+	    /* ----- deal with internal extents ----- */
+	    if (extent_internal_p (e))
+	      {
+		if (!(flags & ME_INCLUDE_INTERNAL))
+		  continue;
+		else if (e == range)
+		  {
+		    /* We're processing internal extents and we've
+		       come across our own special range extent.
+		       (This happens only in adjust_extents*() and
+		       process_extents*(), which handle text
+		       insertion and deletion.) We need to omit
+		       processing of this extent; otherwise
+		       we will probably end up prematurely
+		       terminating this loop. */
+		    continue;
+		  }
+	      }
+	    /* ----- deal with AFTER condition ----- */
+	    if (after)
+	      {
+		/* if e > after, then we can stop skipping extents. */
+		if (EXTENT_LESS (after, e))
+		  after = 0;
+		else /* otherwise, skip this extent. */
+		  continue;
+	      }
+	    /* ----- stop if we're completely outside the range ----- */
+	    /* fetch ST and EN again to track text insertions or deletions */
+	    if (range)
+	      {
+		st = extent_start (range);
+		en = extent_end (range);
+	      }
+	    if (extent_endpoint (e, range_endp) > en)
+	      {
+		/* Can't be mapping over SOE because all extents in
+		   there should overlap ST */
+		assert (stage == 1);
+		break;
+	      }
+	    /* ----- Now actually call the function ----- */
+	    obj2 = extent_object (e);
+	    if (extent_in_region_p (e,
+				    buffer_or_string_memind_to_bytind (obj2,
+								       st),
+				    buffer_or_string_memind_to_bytind (obj2,
+								       en),
+				    flags))
+	      {
+		if ((*fn)(e, arg))
+		  {
+		    /* Function wants us to stop mapping. */
+		    stage = 1; /* so outer for loop will terminate */
+		    break;
+		  }
+	      }
+	  }
+}
+/* ---------- Finished looping. ---------- */
+}
+if (flags & ME_MIGHT_THROW)
+/* This deletes the range extent and frees the marker. */
+unbind_to (count, Qnil);
+else
+{
+/* Delete them ourselves */
+if (range)
+	extent_detach (range);
+if (posm)
+	extent_list_delete_marker (el, posm);
+}
+}
+void
+map_extents (Bufpos from, Bufpos to, map_extents_fun fn,
+	     void *arg, Lisp_Object obj, EXTENT after, unsigned int flags)
+{
+map_extents_bytind (buffer_or_string_bufpos_to_bytind (obj, from),
+		      buffer_or_string_bufpos_to_bytind (obj, to), fn, arg,
+		      obj, after, flags);
+}
+/* ------------------------------- */
+/*         adjust_extents()        */
+/* ------------------------------- */
+/* Add AMOUNT to all extent endpoints in the range (FROM, TO].  This
+happens whenever the gap is moved or (under Mule) a character in a
+string is substituted for a different-length one.  The reason for
+this is that extent endpoints behave just like markers (all memory
+indices do) and this adjustment correct for markers -- see
+adjust_markers().  Note that it is important that we visit all
+extent endpoints in the range, irrespective of whether the
+endpoints are open or closed.
+We could use map_extents() for this (and in fact the function
+was originally written that way), but the gap is in an incoherent
+state when this function is called and this function plays
+around with extent endpoints without detaching and reattaching
+the extents (this is provably correct and saves lots of time),
+so for safety we make it just look at the extent lists directly. */
+void
+adjust_extents (Lisp_Object obj, Memind from, Memind to, int amount)
+{
+int endp;
+int pos;
+int startpos[2];
+Extent_List *el;
+Stack_Of_Extents *soe;
+#ifdef ERROR_CHECK_EXTENTS
+sledgehammer_extent_check (obj);
+#endif
+el = buffer_or_string_extent_list (obj);
+if (!el || !extent_list_num_els(el))
+return;
+/* IMPORTANT! Compute the starting positions of the extents to
+modify BEFORE doing any modification!  Otherwise the starting
+position for the second time through the loop might get
+incorrectly calculated (I got bit by this bug real bad). */
+startpos[0] = extent_list_locate_from_pos (el, from+1, 0);
+startpos[1] = extent_list_locate_from_pos (el, from+1, 1);
+for (endp = 0; endp < 2; endp++)
+{
+for (pos = startpos[endp]; pos < extent_list_num_els (el);
+	   pos++)
+	{
+	  EXTENT e = extent_list_at (el, pos, endp);
+	  if (extent_endpoint (e, endp) > to)
+	    break;
+	  set_extent_endpoint (e,
+			       do_marker_adjustment (extent_endpoint (e, endp),
+						     from, to, amount),
+			       endp);
+	}
+}
+/* The index for the buffer's SOE is a memory index and thus
+needs to be adjusted like a marker. */
+soe = buffer_or_string_stack_of_extents (obj);
+if (soe && soe->pos >= 0)
+soe->pos = do_marker_adjustment (soe->pos, from, to, amount);
+}
+/* ------------------------------- */
+/*  adjust_extents_for_deletion()  */
+/* ------------------------------- */
+struct adjust_extents_for_deletion_arg
+{
+EXTENT_dynarr *list;
+};
+static int
+adjust_extents_for_deletion_mapper (EXTENT extent, void *arg)
+{
+struct adjust_extents_for_deletion_arg *closure =
+(struct adjust_extents_for_deletion_arg *) arg;
+Dynarr_add (closure->list, extent);
+return 0; /* continue mapping */
+}
+/* For all extent endpoints in the range (FROM, TO], move them to the beginning
+of the new gap.   Note that it is important that we visit all extent
+endpoints in the range, irrespective of whether the endpoints are open or
+closed.
+This function deals with weird stuff such as the fact that extents
+may get reordered.
+There is no string correspondent for this because you can't
+delete characters from a string.
+*/
+void
+adjust_extents_for_deletion (Lisp_Object object, Bytind from,
+			     Bytind to, int gapsize, int numdel,
+			     int movegapsize)
+{
+struct adjust_extents_for_deletion_arg closure;
+int i;
+Memind adjust_to = (Memind) (to + gapsize);
+Bytecount amount = - numdel - movegapsize;
+Memind oldsoe = 0, newsoe = 0;
+Stack_Of_Extents *soe = buffer_or_string_stack_of_extents (object);
+#ifdef ERROR_CHECK_EXTENTS
+sledgehammer_extent_check (object);
+#endif
+closure.list = Dynarr_new (EXTENT);
+/* We're going to be playing weird games below with extents and the SOE
+and such, so compute the list now of all the extents that we're going
+to muck with.  If we do the mapping and adjusting together, things can
+get all screwed up. */
+map_extents_bytind (from, to, adjust_extents_for_deletion_mapper,
+		      (void *) &closure, object, 0,
+		      /* extent endpoints move like markers regardless
+			 of their open/closeness. */
+		      ME_ALL_EXTENTS_CLOSED | ME_END_CLOSED |
+		      ME_START_OR_END_IN_REGION | ME_INCLUDE_INTERNAL);
+/*
+Old and new values for the SOE's position. (It gets adjusted
+like a marker, just like extent endpoints.)
+*/
+if (soe)
+{
+oldsoe = soe->pos;
+if (soe->pos >= 0)
+	newsoe = do_marker_adjustment (soe->pos,
+						adjust_to, adjust_to,
+						amount);
+else
+	newsoe = soe->pos;
+}
+for (i = 0; i < Dynarr_length (closure.list); i++)
+{
+EXTENT extent = Dynarr_at (closure.list, i);
+Memind new_start = extent_start (extent);
+Memind new_end = extent_end (extent);
+/* do_marker_adjustment() will not adjust values that should not be
+	 adjusted.  We're passing the same funky arguments to
+	 do_marker_adjustment() as buffer_delete_range() does. */
+new_start =
+	do_marker_adjustment (new_start,
+				       adjust_to, adjust_to,
+				       amount);
+new_end =
+	do_marker_adjustment (new_end,
+				       adjust_to, adjust_to,
+				       amount);
+/* We need to be very careful here so that the SOE doesn't get
+	 corrupted.  We are shrinking extents out of the deleted region
+	 and simultaneously moving the SOE's pos out of the deleted
+	 region, so the SOE should contain the same extents at the end
+	 as at the beginning.  However, extents may get reordered
+	 by this process, so we have to operate by pulling the extents
+	 out of the buffer and SOE, changing their bounds, and then
+	 reinserting them.  In order for the SOE not to get screwed up,
+	 we have to make sure that the SOE's pos points to its old
+	 location whenever we pull an extent out, and points to its
+	 new location whenever we put the extent back in.
+*/
+if (new_start != extent_start (extent) ||
+	  new_end != extent_end (extent))
+	{
+	  extent_detach (extent);
+	  set_extent_start (extent, new_start);
+	  set_extent_end (extent, new_end);
+	  if (soe)
+	    soe->pos = newsoe;
+	  extent_attach (extent);
+	  if (soe)
+	    soe->pos = oldsoe;
+	}
+}
+if (soe)
+soe->pos = newsoe;
+#ifdef ERROR_CHECK_EXTENTS
+sledgehammer_extent_check (object);
+#endif
+Dynarr_free (closure.list);
+}
+/* ------------------------------- */
+/*         extent fragments        */
+/* ------------------------------- */
+/* Imagine that the buffer is divided up into contiguous,
+nonoverlapping "runs" of text such that no extent
+starts or ends within a run (extents that abut the
+run don't count).
+An extent fragment is a structure that holds data about
+the run that contains a particular buffer position (if
+the buffer position is at the junction of two runs, the
+run after the position is used) -- the beginning and
+end of the run, a list of all of the extents in that
+run, the "merged face" that results from merging all of
+the faces corresponding to those extents, the begin and
+end glyphs at the beginning of the run, etc.  This is
+the information that redisplay needs in order to
+display this run.
+Extent fragments have to be very quick to update to
+a new buffer position when moving linearly through
+the buffer.  They rely on the stack-of-extents code,
+which does the heavy-duty algorithmic work of determining
+which extents overly a particular position. */
+/* This function returns the position of the beginning of
+the first run that begins after POS, or returns POS if
+there are no such runs. */
+static Bytind
+extent_find_end_of_run (Lisp_Object obj, Bytind pos, int outside_accessible)
+{
+Extent_List *sel;
+Extent_List *bel = buffer_or_string_extent_list (obj);
+Bytind pos1, pos2;
+int elind1, elind2;
+Memind mempos = buffer_or_string_bytind_to_memind (obj, pos);
+Bytind limit = outside_accessible ?
+buffer_or_string_absolute_end_byte (obj) :
+buffer_or_string_accessible_end_byte (obj);
+if (!bel || !extent_list_num_els(bel))
+return limit;
+sel = buffer_or_string_stack_of_extents_force (obj)->extents;
+soe_move (obj, mempos);
+/* Find the first start position after POS. */
+elind1 = extent_list_locate_from_pos (bel, mempos+1, 0);
+if (elind1 < extent_list_num_els (bel))
+pos1 = buffer_or_string_memind_to_bytind
+(obj, extent_start (extent_list_at (bel, elind1, 0)));
+else
+pos1 = limit;
+/* Find the first end position after POS.  The extent corresponding
+to this position is either in the SOE or is greater than or
+equal to POS1, so we just have to look in the SOE. */
+elind2 = extent_list_locate_from_pos (sel, mempos+1, 1);
+if (elind2 < extent_list_num_els (sel))
+pos2 = buffer_or_string_memind_to_bytind
+(obj, extent_end (extent_list_at (sel, elind2, 1)));
+else
+pos2 = limit;
+return min (min (pos1, pos2), limit);
+}
+static Bytind
+extent_find_beginning_of_run (Lisp_Object obj, Bytind pos,
+			      int outside_accessible)
+{
+Extent_List *sel;
+Extent_List *bel = buffer_or_string_extent_list (obj);
+Bytind pos1, pos2;
+int elind1, elind2;
+Memind mempos = buffer_or_string_bytind_to_memind (obj, pos);
+Bytind limit = outside_accessible ?
+buffer_or_string_absolute_begin_byte (obj) :
+buffer_or_string_accessible_begin_byte (obj);
+if (!bel || !extent_list_num_els(bel))
+return limit;
+sel = buffer_or_string_stack_of_extents_force (obj)->extents;
+soe_move (obj, mempos);
+/* Find the first end position before POS. */
+elind1 = extent_list_locate_from_pos (bel, mempos, 1);
+if (elind1 > 0)
+pos1 = buffer_or_string_memind_to_bytind
+(obj, extent_end (extent_list_at (bel, elind1 - 1, 1)));
+else
+pos1 = limit;
+/* Find the first start position before POS.  The extent corresponding
+to this position is either in the SOE or is less than or
+equal to POS1, so we just have to look in the SOE. */
+elind2 = extent_list_locate_from_pos (sel, mempos, 0);
+if (elind2 > 0)
+pos2 = buffer_or_string_memind_to_bytind
+(obj, extent_start (extent_list_at (sel, elind2 - 1, 0)));
+else
+pos2 = limit;
+return max (max (pos1, pos2), limit);
+}
+struct extent_fragment *
+extent_fragment_new (Lisp_Object buffer_or_string, struct frame *frm)
+{
+struct extent_fragment *ef = xnew_and_zero (struct extent_fragment);
+ef->object = buffer_or_string;
+ef->frm = frm;
+ef->extents = Dynarr_new (EXTENT);
+ef->begin_glyphs = Dynarr_new (glyph_block);
+ef->end_glyphs   = Dynarr_new (glyph_block);
+return ef;
+}
+void
+extent_fragment_delete (struct extent_fragment *ef)
+{
+Dynarr_free (ef->extents);
+Dynarr_free (ef->begin_glyphs);
+Dynarr_free (ef->end_glyphs);
+xfree (ef);
+}
+/* Note:  CONST is losing, but `const' is part of the interface of qsort() */
+static int
+extent_priority_sort_function (const void *humpty, const void *dumpty)
+{
+CONST EXTENT foo = * (CONST EXTENT *) humpty;
+CONST EXTENT bar = * (CONST EXTENT *) dumpty;
+if (extent_priority (foo) < extent_priority (bar))
+return -1;
+return extent_priority (foo) > extent_priority (bar);
+}
+static void
+extent_fragment_sort_by_priority (EXTENT_dynarr *extarr)
+{
+int i;
+/* Sort our copy of the stack by extent_priority.  We use a bubble
+sort here because it's going to be faster than qsort() for small
+numbers of extents (less than 10 or so), and 99.999% of the time
+there won't ever be more extents than this in the stack. */
+if (Dynarr_length (extarr) < 10)
+{
+for (i = 1; i < Dynarr_length (extarr); i++)
+	{
+	  int j = i - 1;
+	  while (j >= 0 &&
+		 (extent_priority (Dynarr_at (extarr, j)) >
+		  extent_priority (Dynarr_at (extarr, j+1))))
+	    {
+	      EXTENT tmp = Dynarr_at (extarr, j);
+	      Dynarr_at (extarr, j) = Dynarr_at (extarr, j+1);
+	      Dynarr_at (extarr, j+1) = tmp;
+	      j--;
+	    }
+	}
+}
+else
+/* But some loser programs mess up and may create a large number
+of extents overlapping the same spot.  This will result in
+catastrophic behavior if we use the bubble sort above. */
+qsort (Dynarr_atp (extarr, 0), Dynarr_length (extarr),
+	   sizeof (EXTENT), extent_priority_sort_function);
+}
+/* If PROP is the `invisible' property of an extent,
+this is 1 if the extent should be treated as invisible.  */
+#define EXTENT_PROP_MEANS_INVISIBLE(buf, prop)			\
+(EQ (buf->invisibility_spec, Qt)				\
+? ! NILP (prop)						\
+: invisible_p (prop, buf->invisibility_spec))
+/* If PROP is the `invisible' property of a extent,
+this is 1 if the extent should be treated as invisible
+and should have an ellipsis.  */
+#define EXTENT_PROP_MEANS_INVISIBLE_WITH_ELLIPSIS(buf, prop)	\
+(EQ (buf->invisibility_spec, Qt)				\
+? 0								\
+: invisible_ellipsis_p (prop, buf->invisibility_spec))
+/* This is like a combination of memq and assq.
+Return 1 if PROPVAL appears as an element of LIST
+or as the car of an element of LIST.
+If PROPVAL is a list, compare each element against LIST
+in that way, and return 1 if any element of PROPVAL is found in LIST.
+Otherwise return 0.
+This function cannot quit.  */
+static int
+invisible_p (REGISTER Lisp_Object propval, Lisp_Object list)
+{
+REGISTER Lisp_Object tail, proptail;
+for (tail = list; CONSP (tail); tail = XCDR (tail))
+{
+REGISTER Lisp_Object tem;
+tem = XCAR (tail);
+if (EQ (propval, tem))
+	return 1;
+if (CONSP (tem) && EQ (propval, XCAR (tem)))
+	return 1;
+}
+if (CONSP (propval))
+for (proptail = propval; CONSP (proptail);
+	 proptail = XCDR (proptail))
+{
+	Lisp_Object propelt;
+	propelt = XCAR (proptail);
+	for (tail = list; CONSP (tail); tail = XCDR (tail))
+	  {
+	    REGISTER Lisp_Object tem;
+	    tem = XCAR (tail);
+	    if (EQ (propelt, tem))
+	      return 1;
+	    if (CONSP (tem) && EQ (propelt, XCAR (tem)))
+	      return 1;
+	  }
+}
+return 0;
+}
+/* Return 1 if PROPVAL appears as the car of an element of LIST
+and the cdr of that element is non-nil.
+If PROPVAL is a list, check each element of PROPVAL in that way,
+and the first time some element is found,
+return 1 if the cdr of that element is non-nil.
+Otherwise return 0.
+This function cannot quit.  */
+static int
+invisible_ellipsis_p (REGISTER Lisp_Object propval, Lisp_Object list)
+{
+REGISTER Lisp_Object tail, proptail;
+for (tail = list; CONSP (tail); tail = XCDR (tail))
+{
+REGISTER Lisp_Object tem;
+tem = XCAR (tail);
+if (CONSP (tem) && EQ (propval, XCAR (tem)))
+	return ! NILP (XCDR (tem));
+}
+if (CONSP (propval))
+for (proptail = propval; CONSP (proptail);
+	 proptail = XCDR (proptail))
+{
+	Lisp_Object propelt;
+	propelt = XCAR (proptail);
+	for (tail = list; CONSP (tail); tail = XCDR (tail))
+	  {
+	    REGISTER Lisp_Object tem;
+	    tem = XCAR (tail);
+	    if (CONSP (tem) && EQ (propelt, XCAR (tem)))
+	      return ! NILP (XCDR (tem));
+	  }
+}
+return 0;
+}
+face_index
+extent_fragment_update (struct window *w, struct extent_fragment *ef,
+			Bytind pos)
+{
+int i;
+Extent_List *sel =
+buffer_or_string_stack_of_extents_force (ef->object)->extents;
+EXTENT lhe = 0;
+struct extent dummy_lhe_extent;
+Memind mempos = buffer_or_string_bytind_to_memind (ef->object, pos);
+#ifdef ERROR_CHECK_EXTENTS
+assert (pos >= buffer_or_string_accessible_begin_byte (ef->object)
+	  && pos <= buffer_or_string_accessible_end_byte (ef->object));
+#endif
+Dynarr_reset (ef->extents);
+Dynarr_reset (ef->begin_glyphs);
+Dynarr_reset (ef->end_glyphs);
+ef->previously_invisible = ef->invisible;
+if (ef->invisible)
+{
+if (ef->invisible_ellipses)
+	ef->invisible_ellipses_already_displayed = 1;
+}
+else
+ef->invisible_ellipses_already_displayed = 0;
+ef->invisible = 0;
+ef->invisible_ellipses = 0;
+/* Set up the begin and end positions. */
+ef->pos = pos;
+ef->end = extent_find_end_of_run (ef->object, pos, 0);
+/* Note that extent_find_end_of_run() already moved the SOE for us. */
+/* soe_move (ef->object, mempos); */
+/* Determine the begin glyphs at POS. */
+for (i = 0; i < extent_list_num_els (sel); i++)
+{
+EXTENT e = extent_list_at (sel, i, 0);
+if (extent_start (e) == mempos && !NILP (extent_begin_glyph (e)))
+	{
+	  Lisp_Object glyph = extent_begin_glyph (e);
+	  struct glyph_block gb;
+	  gb.glyph = glyph;
+	  XSETEXTENT (gb.extent, e);
+	  Dynarr_add (ef->begin_glyphs, gb);
+	}
+}
+/* Determine the end glyphs at POS. */
+for (i = 0; i < extent_list_num_els (sel); i++)
+{
+EXTENT e = extent_list_at (sel, i, 1);
+if (extent_end (e) == mempos && !NILP (extent_end_glyph (e)))
+	{
+	  Lisp_Object glyph = extent_end_glyph (e);
+	  struct glyph_block gb;
+	  gb.glyph = glyph;
+	  XSETEXTENT (gb.extent, e);
+	  Dynarr_add (ef->end_glyphs, gb);
+	}
+}
+/* We tried determining all the charsets used in the run here,
+but that fails even if we only do the current line -- display
+tables or non-printable characters might cause other charsets
+to be used. */
+/* Determine whether the last-highlighted-extent is present. */
+if (EXTENTP (Vlast_highlighted_extent))
+lhe = XEXTENT (Vlast_highlighted_extent);
+/* Now add all extents that overlap the character after POS and
+have a non-nil face.  Also check if the character is invisible. */
+for (i = 0; i < extent_list_num_els (sel); i++)
+{
+EXTENT e = extent_list_at (sel, i, 0);
+if (extent_end (e) > mempos)
+	{
+	  Lisp_Object invis_prop = extent_invisible (e);
+	  if (!NILP (invis_prop))
+	    {
+	      if (!BUFFERP (ef->object))
+		/* #### no `string-invisibility-spec' */
+		ef->invisible = 1;
+	      else
+		{
+		  if (!ef->invisible_ellipses_already_displayed &&
+		      EXTENT_PROP_MEANS_INVISIBLE_WITH_ELLIPSIS
+		      (XBUFFER (ef->object), invis_prop))
+		    {
+		      ef->invisible = 1;
+		      ef->invisible_ellipses = 1;
+		    }
+		  else if (EXTENT_PROP_MEANS_INVISIBLE
+			   (XBUFFER (ef->object), invis_prop))
+		    ef->invisible = 1;
+		}
+	    }
+	  /* Remember that one of the extents in the list might be our
+	     dummy extent representing the highlighting that is
+	     attached to some other extent that is currently
+	     mouse-highlighted.  When an extent is mouse-highlighted,
+	     it is as if there are two extents there, of potentially
+	     different priorities: the extent being highlighted, with
+	     whatever face and priority it has; and an ephemeral
+	     extent in the `mouse-face' face with
+	     `mouse-highlight-priority'.
+	     */
+	  if (!NILP (extent_face (e)))
+	    Dynarr_add (ef->extents, e);
+	  if (e == lhe)
+	    {
+	      Lisp_Object f;
+	      /* zeroing isn't really necessary; we only deref `priority'
+		 and `face' */
+	      xzero (dummy_lhe_extent);
+	      set_extent_priority (&dummy_lhe_extent,
+				   mouse_highlight_priority);
+	      /* Need to break up the following expression, due to an */
+	      /* error in the Digital UNIX 3.2g C compiler (Digital */
+	      /* UNIX Compiler Driver 3.11). */
+	      f = extent_mouse_face (lhe);
+	      extent_face (&dummy_lhe_extent) = f;
+	      Dynarr_add (ef->extents, &dummy_lhe_extent);
+	    }
+	  /* since we are looping anyway, we might as well do this here */
+	  if ((!NILP(extent_initial_redisplay_function (e))) &&
+	      !extent_in_red_event_p(e))
+	    {
+	      Lisp_Object function = extent_initial_redisplay_function (e);
+	      Lisp_Object obj;
+	      /* printf ("initial redisplay function called!\n "); */
+	      /* print_extent_2 (e);
+	         printf ("\n"); */
+	      /* FIXME: One should probably inhibit the displaying of
+		 this extent to reduce flicker */
+	      extent_in_red_event_p(e) = 1;
+	      /* call the function */
+	      XSETEXTENT(obj,e);
+	      if(!NILP(function))
+	         Fenqueue_eval_event(function,obj);
+	    }
+	}
+}
+extent_fragment_sort_by_priority (ef->extents);
+/* Now merge the faces together into a single face.  The code to
+do this is in faces.c because it involves manipulating faces. */
+return get_extent_fragment_face_cache_index (w, ef);
+}
+/************************************************************************/
+/*	  	        extent-object methods				*/
+/************************************************************************/
+/* These are the basic helper functions for handling the allocation of
+extent objects.  They are similar to the functions for other
+lrecord objects.  allocate_extent() is in alloc.c, not here. */
+static Lisp_Object mark_extent (Lisp_Object);
+static int extent_equal (Lisp_Object, Lisp_Object, int depth);
+static unsigned long extent_hash (Lisp_Object obj, int depth);
+static void print_extent (Lisp_Object obj, Lisp_Object printcharfun,
+			  int escapeflag);
+static Lisp_Object extent_getprop (Lisp_Object obj, Lisp_Object prop);
+static int extent_putprop (Lisp_Object obj, Lisp_Object prop,
+			   Lisp_Object value);
+static int extent_remprop (Lisp_Object obj, Lisp_Object prop);
+static Lisp_Object extent_plist (Lisp_Object obj);
+static const struct lrecord_description extent_description[] = {
+{ XD_LISP_OBJECT, offsetof(struct extent, object), 2 },
+{ XD_LISP_OBJECT, offsetof(struct extent, plist), 1 },
+{ XD_END }
+};
+DEFINE_BASIC_LRECORD_IMPLEMENTATION_WITH_PROPS ("extent", extent,
+						mark_extent,
+						print_extent,
+						/* NOTE: If you declare a
+						   finalization method here,
+						   it will NOT be called.
+						   Shaft city. */
+						0,
+						extent_equal, extent_hash,
+						extent_description,
+						extent_getprop, extent_putprop,
+						extent_remprop, extent_plist,
+						struct extent);
+static Lisp_Object
+mark_extent (Lisp_Object obj)
+{
+struct extent *extent = XEXTENT (obj);
+mark_object (extent_object (extent));
+mark_object (extent_no_chase_normal_field (extent, face));
+return extent->plist;
+}
+static void
+print_extent_1 (Lisp_Object obj, Lisp_Object printcharfun, int escapeflag)
+{
+EXTENT ext = XEXTENT (obj);
+EXTENT anc = extent_ancestor (ext);
+Lisp_Object tail;
+char buf[64], *bp = buf;
+/* Retrieve the ancestor and use it, for faster retrieval of properties */
+if (!NILP (extent_begin_glyph (anc))) *bp++ = '*';
+*bp++ = (extent_start_open_p (anc) ? '(': '[');
+if (extent_detached_p (ext))
+strcpy (bp, "detached");
+else
+sprintf (bp, "%ld, %ld",
+	     (long) XINT (Fextent_start_position (obj)),
+	     (long) XINT (Fextent_end_position (obj)));
+bp += strlen (bp);
+*bp++ = (extent_end_open_p (anc) ? ')': ']');
+if (!NILP (extent_end_glyph (anc))) *bp++ = '*';
+*bp++ = ' ';
+if (!NILP (extent_read_only (anc))) *bp++ = '%';
+if (!NILP (extent_mouse_face (anc))) *bp++ = 'H';
+if (extent_unique_p (anc)) *bp++ = 'U';
+else if (extent_duplicable_p (anc)) *bp++ = 'D';
+if (!NILP (extent_invisible (anc))) *bp++ = 'I';
+if (!NILP (extent_read_only (anc)) || !NILP (extent_mouse_face (anc)) ||
+extent_unique_p (anc) ||
+extent_duplicable_p (anc) || !NILP (extent_invisible (anc)))
+*bp++ = ' ';
+*bp = '\0';
+write_c_string (buf, printcharfun);
+tail = extent_plist_slot (anc);
+for (; !NILP (tail); tail = Fcdr (Fcdr (tail)))
+{
+Lisp_Object v = XCAR (XCDR (tail));
+if (NILP (v)) continue;
+print_internal (XCAR (tail), printcharfun, escapeflag);
+write_c_string (" ", printcharfun);
+}
+sprintf (buf, "0x%lx", (long) ext);
+write_c_string (buf, printcharfun);
+}
+static void
+print_extent (Lisp_Object obj, Lisp_Object printcharfun, int escapeflag)
+{
+if (escapeflag)
+{
+CONST char *title = "";
+CONST char *name = "";
+CONST char *posttitle = "";
+Lisp_Object obj2 = Qnil;
+/* Destroyed extents have 't' in the object field, causing
+	 extent_object() to abort (maybe). */
+if (EXTENT_LIVE_P (XEXTENT (obj)))
+	obj2 = extent_object (XEXTENT (obj));
+if (NILP (obj2))
+	title = "no buffer";
+else if (BUFFERP (obj2))
+	{
+	  if (BUFFER_LIVE_P (XBUFFER (obj2)))
+	    {
+	      title = "buffer ";
+	      name = (char *) XSTRING_DATA (XBUFFER (obj2)->name);
+	    }
+	  else
+	    {
+	      title = "Killed Buffer";
+	      name = "";
+	    }
+	}
+else
+	{
+	  assert (STRINGP (obj2));
+	  title = "string \"";
+	  posttitle = "\"";
+	  name = (char *) XSTRING_DATA (obj2);
+	}
+if (print_readably)
+	{
+	  if (!EXTENT_LIVE_P (XEXTENT (obj)))
+	    error ("printing unreadable object #<destroyed extent>");
+	  else
+	    error ("printing unreadable object #<extent 0x%lx>",
+		   (long) XEXTENT (obj));
+	}
+if (!EXTENT_LIVE_P (XEXTENT (obj)))
+	write_c_string ("#<destroyed extent", printcharfun);
+else
+	{
+	  char *buf = (char *)
+	    alloca (strlen (title) + strlen (name) + strlen (posttitle) + 1);
+	  write_c_string ("#<extent ", printcharfun);
+	  print_extent_1 (obj, printcharfun, escapeflag);
+	  write_c_string (extent_detached_p (XEXTENT (obj))
+			  ? " from " : " in ", printcharfun);
+	  sprintf (buf, "%s%s%s", title, name, posttitle);
+	  write_c_string (buf, printcharfun);
+	}
+}
+else
+{
+if (print_readably)
+	error ("printing unreadable object #<extent>");
+write_c_string ("#<extent", printcharfun);
+}
+write_c_string (">", printcharfun);
+}
+static int
+properties_equal (EXTENT e1, EXTENT e2, int depth)
+{
+/* When this function is called, all indirections have been followed.
+Thus, the indirection checks in the various macros below will not
+amount to anything, and could be removed.  However, the time
+savings would probably not be significant. */
+if (!(EQ (extent_face (e1), extent_face (e2)) &&
+	extent_priority (e1) == extent_priority (e2) &&
+	internal_equal (extent_begin_glyph (e1), extent_begin_glyph (e2),
+			depth + 1) &&
+	internal_equal (extent_end_glyph (e1), extent_end_glyph (e2),
+			depth + 1)))
+return 0;
+/* compare the bit flags. */
+{
+/* The has_aux field should not be relevant. */
+int e1_has_aux = e1->flags.has_aux;
+int e2_has_aux = e2->flags.has_aux;
+int value;
+e1->flags.has_aux = e2->flags.has_aux = 0;
+value = memcmp (&e1->flags, &e2->flags, sizeof (e1->flags));
+e1->flags.has_aux = e1_has_aux;
+e2->flags.has_aux = e2_has_aux;
+if (value)
+return 0;
+}
+/* compare the random elements of the plists. */
+return !plists_differ (extent_no_chase_plist (e1),
+			 extent_no_chase_plist (e2),
+			 0, 0, depth + 1);
+}
+static int
+extent_equal (Lisp_Object obj1, Lisp_Object obj2, int depth)
+{
+struct extent *e1 = XEXTENT (obj1);
+struct extent *e2 = XEXTENT (obj2);
+return
+(extent_start (e1) == extent_start (e2) &&
+extent_end   (e1) == extent_end   (e2) &&
+internal_equal (extent_object (e1), extent_object (e2), depth + 1) &&
+properties_equal (extent_ancestor (e1), extent_ancestor (e2),
+		       depth));
+}
+static unsigned long
+extent_hash (Lisp_Object obj, int depth)
+{
+struct extent *e = XEXTENT (obj);
+/* No need to hash all of the elements; that would take too long.
+Just hash the most common ones. */
+return HASH3 (extent_start (e), extent_end (e),
+		internal_hash (extent_object (e), depth + 1));
+}
+static Lisp_Object
+extent_getprop (Lisp_Object obj, Lisp_Object prop)
+{
+return Fextent_property (obj, prop, Qunbound);
+}
+static int
+extent_putprop (Lisp_Object obj, Lisp_Object prop, Lisp_Object value)
+{
+Fset_extent_property (obj, prop, value);
+return 1;
+}
+static int
+extent_remprop (Lisp_Object obj, Lisp_Object prop)
+{
+EXTENT ext = XEXTENT (obj);
+/* This list is taken from Fset_extent_property, and should be kept
+in synch.  */
+if (EQ (prop, Qread_only)
+|| EQ (prop, Qunique)
+|| EQ (prop, Qduplicable)
+|| EQ (prop, Qinvisible)
+|| EQ (prop, Qdetachable)
+|| EQ (prop, Qdetached)
+|| EQ (prop, Qdestroyed)
+|| EQ (prop, Qpriority)
+|| EQ (prop, Qface)
+|| EQ (prop, Qinitial_redisplay_function)
+|| EQ (prop, Qafter_change_functions)
+|| EQ (prop, Qbefore_change_functions)
+|| EQ (prop, Qmouse_face)
+|| EQ (prop, Qhighlight)
+|| EQ (prop, Qbegin_glyph_layout)
+|| EQ (prop, Qend_glyph_layout)
+|| EQ (prop, Qglyph_layout)
+|| EQ (prop, Qbegin_glyph)
+|| EQ (prop, Qend_glyph)
+|| EQ (prop, Qstart_open)
+|| EQ (prop, Qend_open)
+|| EQ (prop, Qstart_closed)
+|| EQ (prop, Qend_closed)
+|| EQ (prop, Qkeymap))
+{
+/* #### Is this correct, anyway?  */
+return -1;
+}
+return external_remprop (extent_plist_addr (ext), prop, 0, ERROR_ME);
+}
+static Lisp_Object
+extent_plist (Lisp_Object obj)
+{
+return Fextent_properties (obj);
+}
+/************************************************************************/
+/*			basic extent accessors				*/
+/************************************************************************/
+/* These functions are for checking externally-passed extent objects
+and returning an extent's basic properties, which include the
+buffer the extent is associated with, the endpoints of the extent's
+range, the open/closed-ness of those endpoints, and whether the
+extent is detached.  Manipulating these properties requires
+manipulating the ordered lists that hold extents; thus, functions
+to do that are in a later section. */
+/* Given a Lisp_Object that is supposed to be an extent, make sure it
+is OK and return an extent pointer.  Extents can be in one of four
+states:
+1) destroyed
+2) detached and not associated with a buffer
+3) detached and associated with a buffer
+4) attached to a buffer
+If FLAGS is 0, types 2-4 are allowed.  If FLAGS is DE_MUST_HAVE_BUFFER,
+types 3-4 are allowed.  If FLAGS is DE_MUST_BE_ATTACHED, only type 4
+is allowed.
+*/
+static EXTENT
+decode_extent (Lisp_Object extent_obj, unsigned int flags)
+{
+EXTENT extent;
+Lisp_Object obj;
+CHECK_LIVE_EXTENT (extent_obj);
+extent = XEXTENT (extent_obj);
+obj = extent_object (extent);
+/* the following condition will fail if we're dealing with a freed extent */
+assert (NILP (obj) || BUFFERP (obj) || STRINGP (obj));
+if (flags & DE_MUST_BE_ATTACHED)
+flags |= DE_MUST_HAVE_BUFFER;
+/* if buffer is dead, then convert extent to have no buffer. */
+if (BUFFERP (obj) && !BUFFER_LIVE_P (XBUFFER (obj)))
+obj = extent_object (extent) = Qnil;
+assert (!NILP (obj) || extent_detached_p (extent));
+if ((NILP (obj) && (flags & DE_MUST_HAVE_BUFFER))
+|| (extent_detached_p (extent) && (flags & DE_MUST_BE_ATTACHED)))
+{
+signal_simple_error ("extent doesn't belong to a buffer or string",
+			   extent_obj);
+}
+return extent;
+}
+/* Note that the returned value is a buffer position, not a byte index. */
+static Lisp_Object
+extent_endpoint_external (Lisp_Object extent_obj, int endp)
+{
+EXTENT extent = decode_extent (extent_obj, 0);
+if (extent_detached_p (extent))
+return Qnil;
+else
+return make_int (extent_endpoint_bufpos (extent, endp));
+}
+DEFUN ("extentp", Fextentp, 1, 1, 0, /*
+Return t if OBJECT is an extent.
+*/
+(object))
+{
+return EXTENTP (object) ? Qt : Qnil;
+}
+DEFUN ("extent-live-p", Fextent_live_p, 1, 1, 0, /*
+Return t if OBJECT is an extent that has not been destroyed.
+*/
+(object))
+{
+return EXTENTP (object) && EXTENT_LIVE_P (XEXTENT (object)) ? Qt : Qnil;
+}
+DEFUN ("extent-detached-p", Fextent_detached_p, 1, 1, 0, /*
+Return t if EXTENT is detached.
+*/
+(extent))
+{
+return extent_detached_p (decode_extent (extent, 0)) ? Qt : Qnil;
+}
+DEFUN ("extent-object", Fextent_object, 1, 1, 0, /*
+Return object (buffer or string) that EXTENT refers to.
+*/
+(extent))
+{
+return extent_object (decode_extent (extent, 0));
+}
+DEFUN ("extent-start-position", Fextent_start_position, 1, 1, 0, /*
+Return start position of EXTENT, or nil if EXTENT is detached.
+*/
+(extent))
+{
+return extent_endpoint_external (extent, 0);
+}
+DEFUN ("extent-end-position", Fextent_end_position, 1, 1, 0, /*
+Return end position of EXTENT, or nil if EXTENT is detached.
+*/
+(extent))
+{
+return extent_endpoint_external (extent, 1);
+}
+DEFUN ("extent-length", Fextent_length, 1, 1, 0, /*
+Return length of EXTENT in characters.
+*/
+(extent))
+{
+EXTENT e = decode_extent (extent, DE_MUST_BE_ATTACHED);
+return make_int (extent_endpoint_bufpos (e, 1)
+		   - extent_endpoint_bufpos (e, 0));
+}
+DEFUN ("next-extent", Fnext_extent, 1, 1, 0, /*
+Find next extent after EXTENT.
+If EXTENT is a buffer return the first extent in the buffer; likewise
+for strings.
+Extents in a buffer are ordered in what is called the "display"
+order, which sorts by increasing start positions and then by *decreasing*
+end positions.
+If you want to perform an operation on a series of extents, use
+`map-extents' instead of this function; it is much more efficient.
+The primary use of this function should be to enumerate all the
+extents in a buffer.
+Note: The display order is not necessarily the order that `map-extents'
+processes extents in!
+*/
+(extent))
+{
+Lisp_Object val;
+EXTENT next;
+if (EXTENTP (extent))
+next = extent_next (decode_extent (extent, DE_MUST_BE_ATTACHED));
+else
+next = extent_first (decode_buffer_or_string (extent));
+if (!next)
+return Qnil;
+XSETEXTENT (val, next);
+return val;
+}
+DEFUN ("previous-extent", Fprevious_extent, 1, 1, 0, /*
+Find last extent before EXTENT.
+If EXTENT is a buffer return the last extent in the buffer; likewise
+for strings.
+This function is analogous to `next-extent'.
+*/
+(extent))
+{
+Lisp_Object val;
+EXTENT prev;
+if (EXTENTP (extent))
+prev = extent_previous (decode_extent (extent, DE_MUST_BE_ATTACHED));
+else
+prev = extent_last (decode_buffer_or_string (extent));
+if (!prev)
+return Qnil;
+XSETEXTENT (val, prev);
+return val;
+}
+#ifdef DEBUG_XEMACS
+DEFUN ("next-e-extent", Fnext_e_extent, 1, 1, 0, /*
+Find next extent after EXTENT using the "e" order.
+If EXTENT is a buffer return the first extent in the buffer; likewise
+for strings.
+*/
+(extent))
+{
+Lisp_Object val;
+EXTENT next;
+if (EXTENTP (extent))
+next = extent_e_next (decode_extent (extent, DE_MUST_BE_ATTACHED));
+else
+next = extent_e_first (decode_buffer_or_string (extent));
+if (!next)
+return Qnil;
+XSETEXTENT (val, next);
+return val;
+}
+DEFUN ("previous-e-extent", Fprevious_e_extent, 1, 1, 0, /*
+Find last extent before EXTENT using the "e" order.
+If EXTENT is a buffer return the last extent in the buffer; likewise
+for strings.
+This function is analogous to `next-e-extent'.
+*/
+(extent))
+{
+Lisp_Object val;
+EXTENT prev;
+if (EXTENTP (extent))
+prev = extent_e_previous (decode_extent (extent, DE_MUST_BE_ATTACHED));
+else
+prev = extent_e_last (decode_buffer_or_string (extent));
+if (!prev)
+return Qnil;
+XSETEXTENT (val, prev);
+return val;
+}
+#endif
+DEFUN ("next-extent-change", Fnext_extent_change, 1, 2, 0, /*
+Return the next position after POS where an extent begins or ends.
+If POS is at the end of the buffer or string, POS will be returned;
+otherwise a position greater than POS will always be returned.
+If BUFFER is nil, the current buffer is assumed.
+*/
+(pos, object))
+{
+Lisp_Object obj = decode_buffer_or_string (object);
+Bytind bpos;
+bpos = get_buffer_or_string_pos_byte (obj, pos, GB_ALLOW_PAST_ACCESSIBLE);
+bpos = extent_find_end_of_run (obj, bpos, 1);
+return make_int (buffer_or_string_bytind_to_bufpos (obj, bpos));
+}
+DEFUN ("previous-extent-change", Fprevious_extent_change, 1, 2, 0, /*
+Return the last position before POS where an extent begins or ends.
+If POS is at the beginning of the buffer or string, POS will be returned;
+otherwise a position less than POS will always be returned.
+If OBJECT is nil, the current buffer is assumed.
+*/
+(pos, object))
+{
+Lisp_Object obj = decode_buffer_or_string (object);
+Bytind bpos;
+bpos = get_buffer_or_string_pos_byte (obj, pos, GB_ALLOW_PAST_ACCESSIBLE);
+bpos = extent_find_beginning_of_run (obj, bpos, 1);
+return make_int (buffer_or_string_bytind_to_bufpos (obj, bpos));
+}
+/************************************************************************/
+/*		    	parent and children stuff			*/
+/************************************************************************/
+DEFUN ("extent-parent", Fextent_parent, 1, 1, 0, /*
+Return the parent (if any) of EXTENT.
+If an extent has a parent, it derives all its properties from that extent
+and has no properties of its own. (The only "properties" that the
+extent keeps are the buffer/string it refers to and the start and end
+points.) It is possible for an extent's parent to itself have a parent.
+*/
+(extent))
+/* do I win the prize for the strangest split infinitive? */
+{
+EXTENT e = decode_extent (extent, 0);
+return extent_parent (e);
+}
+DEFUN ("extent-children", Fextent_children, 1, 1, 0, /*
+Return a list of the children (if any) of EXTENT.
+The children of an extent are all those extents whose parent is that extent.
+This function does not recursively trace children of children.
+\(To do that, use `extent-descendants'.)
+*/
+(extent))
+{
+EXTENT e = decode_extent (extent, 0);
+Lisp_Object children = extent_children (e);
+if (!NILP (children))
+return Fcopy_sequence (XWEAK_LIST_LIST (children));
+else
+return Qnil;
+}
+static void
+remove_extent_from_children_list (EXTENT e, Lisp_Object child)
+{
+Lisp_Object children = extent_children (e);
+#ifdef ERROR_CHECK_EXTENTS
+assert (!NILP (memq_no_quit (child, XWEAK_LIST_LIST (children))));
+#endif
+XWEAK_LIST_LIST (children) =
+delq_no_quit (child, XWEAK_LIST_LIST (children));
+}
+static void
+add_extent_to_children_list (EXTENT e, Lisp_Object child)
+{
+Lisp_Object children = extent_children (e);
+if (NILP (children))
+{
+children = make_weak_list (WEAK_LIST_SIMPLE);
+set_extent_no_chase_aux_field (e, children, children);
+}
+#ifdef ERROR_CHECK_EXTENTS
+assert (NILP (memq_no_quit (child, XWEAK_LIST_LIST (children))));
+#endif
+XWEAK_LIST_LIST (children) = Fcons (child, XWEAK_LIST_LIST (children));
+}
+DEFUN ("set-extent-parent", Fset_extent_parent, 2, 2, 0, /*
+Set the parent of EXTENT to PARENT (may be nil).
+See `extent-parent'.
+*/
+(extent, parent))
+{
+EXTENT e = decode_extent (extent, 0);
+Lisp_Object cur_parent = extent_parent (e);
+Lisp_Object rest;
+XSETEXTENT (extent, e);
+if (!NILP (parent))
+CHECK_LIVE_EXTENT (parent);
+if (EQ (parent, cur_parent))
+return Qnil;
+for (rest = parent; !NILP (rest); rest = extent_parent (XEXTENT (rest)))
+if (EQ (rest, extent))
+signal_simple_error ("Circular parent chain would result", extent);
+if (NILP (parent))
+{
+remove_extent_from_children_list (XEXTENT (cur_parent), extent);
+set_extent_no_chase_aux_field (e, parent, Qnil);
+e->flags.has_parent = 0;
+}
+else
+{
+add_extent_to_children_list (XEXTENT (parent), extent);
+set_extent_no_chase_aux_field (e, parent, parent);
+e->flags.has_parent = 1;
+}
+/* changing the parent also changes the properties of all children. */
+{
+int old_invis = (!NILP (cur_parent) &&
+		     !NILP (extent_invisible (XEXTENT (cur_parent))));
+int new_invis = (!NILP (parent) &&
+		     !NILP (extent_invisible (XEXTENT (parent))));
+extent_maybe_changed_for_redisplay (e, 1, new_invis != old_invis);
+}
+return Qnil;
+}
+/************************************************************************/
+/*		    	basic extent mutators				*/
+/************************************************************************/
+/* Note:  If you track non-duplicable extents by undo, you'll get bogus
+undo records for transient extents via update-extent.
+For example, query-replace will do this.
+*/
+static void
+set_extent_endpoints_1 (EXTENT extent, Memind start, Memind end)
+{
+#ifdef ERROR_CHECK_EXTENTS
+Lisp_Object obj = extent_object (extent);
+assert (start <= end);
+if (BUFFERP (obj))
+{
+assert (valid_memind_p (XBUFFER (obj), start));
+assert (valid_memind_p (XBUFFER (obj), end));
+}
+#endif
+/* Optimization: if the extent is already where we want it to be,
+do nothing. */
+if (!extent_detached_p (extent) && extent_start (extent) == start &&
+extent_end (extent) == end)
+return;
+if (extent_detached_p (extent))
+{
+if (extent_duplicable_p (extent))
+	{
+	  Lisp_Object extent_obj;
+	  XSETEXTENT (extent_obj, extent);
+	  record_extent (extent_obj, 1);
+	}
+}
+else
+extent_detach (extent);
+set_extent_start (extent, start);
+set_extent_end (extent, end);
+extent_attach (extent);
+}
+/* Set extent's endpoints to S and E, and put extent in buffer or string
+OBJECT. (If OBJECT is nil, do not change the extent's object.) */
+void
+set_extent_endpoints (EXTENT extent, Bytind s, Bytind e, Lisp_Object object)
+{
+Memind start, end;
+if (NILP (object))
+{
+object = extent_object (extent);
+assert (!NILP (object));
+}
+else if (!EQ (object, extent_object (extent)))
+{
+extent_detach (extent);
+extent_object (extent) = object;
+}
+start = s < 0 ? extent_start (extent) :
+buffer_or_string_bytind_to_memind (object, s);
+end = e < 0 ? extent_end (extent) :
+buffer_or_string_bytind_to_memind (object, e);
+set_extent_endpoints_1 (extent, start, end);
+}
+static void
+set_extent_openness (EXTENT extent, int start_open, int end_open)
+{
+if (start_open != -1)
+extent_start_open_p (extent) = start_open;
+if (end_open != -1)
+extent_end_open_p (extent) = end_open;
+/* changing the open/closedness of an extent does not affect
+redisplay. */
+}
+static EXTENT
+make_extent_internal (Lisp_Object object, Bytind from, Bytind to)
+{
+EXTENT extent;
+extent = make_extent_detached (object);
+set_extent_endpoints (extent, from, to, Qnil);
+return extent;
+}
+static EXTENT
+copy_extent (EXTENT original, Bytind from, Bytind to, Lisp_Object object)
+{
+EXTENT e;
+e = make_extent_detached (object);
+if (from >= 0)
+set_extent_endpoints (e, from, to, Qnil);
+e->plist = Fcopy_sequence (original->plist);
+memcpy (&e->flags, &original->flags, sizeof (e->flags));
+if (e->flags.has_aux)
+{
+/* also need to copy the aux struct.  It won't work for
+	 this extent to share the same aux struct as the original
+	 one. */
+struct extent_auxiliary *data =
+	alloc_lcrecord_type (struct extent_auxiliary,
+			     &lrecord_extent_auxiliary);
+copy_lcrecord (data, XEXTENT_AUXILIARY (XCAR (original->plist)));
+XSETEXTENT_AUXILIARY (XCAR (e->plist), data);
+}
+{
+/* we may have just added another child to the parent extent. */
+Lisp_Object parent = extent_parent (e);
+if (!NILP (parent))
+{
+	Lisp_Object extent;
+	XSETEXTENT (extent, e);
+	add_extent_to_children_list (XEXTENT (parent), extent);
+}
+}
+return e;
+}
+static void
+destroy_extent (EXTENT extent)
+{
+Lisp_Object rest, nextrest, children;
+Lisp_Object extent_obj;
+if (!extent_detached_p (extent))
+extent_detach (extent);
+/* disassociate the extent from its children and parent */
+children = extent_children (extent);
+if (!NILP (children))
+{
+LIST_LOOP_DELETING (rest, nextrest, XWEAK_LIST_LIST (children))
+	Fset_extent_parent (XCAR (rest), Qnil);
+}
+XSETEXTENT (extent_obj, extent);
+Fset_extent_parent (extent_obj, Qnil);
+/* mark the extent as destroyed */
+extent_object (extent) = Qt;
+}
+DEFUN ("make-extent", Fmake_extent, 2, 3, 0, /*
+Make an extent for the range [FROM, TO) in BUFFER-OR-STRING.
+BUFFER-OR-STRING defaults to the current buffer.  Insertions at point
+TO will be outside of the extent; insertions at FROM will be inside the
+extent, causing the extent to grow. (This is the same way that markers
+behave.) You can change the behavior of insertions at the endpoints
+using `set-extent-property'.  The extent is initially detached if both
+FROM and TO are nil, and in this case BUFFER-OR-STRING defaults to nil,
+meaning the extent is in no buffer and no string.
+*/
+(from, to, buffer_or_string))
+{
+Lisp_Object extent_obj;
+Lisp_Object obj;
+obj = decode_buffer_or_string (buffer_or_string);
+if (NILP (from) && NILP (to))
+{
+if (NILP (buffer_or_string))
+	obj = Qnil;
+XSETEXTENT (extent_obj, make_extent_detached (obj));
+}
+else
+{
+Bytind start, end;
+get_buffer_or_string_range_byte (obj, from, to, &start, &end,
+				       GB_ALLOW_PAST_ACCESSIBLE);
+XSETEXTENT (extent_obj, make_extent_internal (obj, start, end));
+}
+return extent_obj;
+}
+DEFUN ("copy-extent", Fcopy_extent, 1, 2, 0, /*
+Make a copy of EXTENT.  It is initially detached.
+Optional argument BUFFER-OR-STRING defaults to EXTENT's buffer or string.
+*/
+(extent, buffer_or_string))
+{
+EXTENT ext = decode_extent (extent, 0);
+if (NILP (buffer_or_string))
+buffer_or_string = extent_object (ext);
+else
+buffer_or_string = decode_buffer_or_string (buffer_or_string);
+XSETEXTENT (extent, copy_extent (ext, -1, -1, buffer_or_string));
+return extent;
+}
+DEFUN ("delete-extent", Fdelete_extent, 1, 1, 0, /*
+Remove EXTENT from its buffer and destroy it.
+This does not modify the buffer's text, only its display properties.
+The extent cannot be used thereafter.
+*/
+(extent))
+{
+EXTENT ext;
+/* We do not call decode_extent() here because already-destroyed
+extents are OK. */
+CHECK_EXTENT (extent);
+ext = XEXTENT (extent);
+if (!EXTENT_LIVE_P (ext))
+return Qnil;
+destroy_extent (ext);
+return Qnil;
+}
+DEFUN ("detach-extent", Fdetach_extent, 1, 1, 0, /*
+Remove EXTENT from its buffer in such a way that it can be re-inserted.
+An extent is also detached when all of its characters are all killed by a
+deletion, unless its `detachable' property has been unset.
+Extents which have the `duplicable' attribute are tracked by the undo
+mechanism.  Detachment via `detach-extent' and string deletion is recorded,
+as is attachment via `insert-extent' and string insertion.  Extent motion,
+face changes, and attachment via `make-extent' and `set-extent-endpoints'
+are not recorded.  This means that extent changes which are to be undo-able
+must be performed by character editing, or by insertion and detachment of
+duplicable extents.
+*/
+(extent))
+{
+EXTENT ext = decode_extent (extent, 0);
+if (extent_detached_p (ext))
+return extent;
+if (extent_duplicable_p (ext))
+record_extent (extent, 0);
+extent_detach (ext);
+return extent;
+}
+DEFUN ("set-extent-endpoints", Fset_extent_endpoints, 3, 4, 0, /*
+Set the endpoints of EXTENT to START, END.
+If START and END are null, call detach-extent on EXTENT.
+BUFFER-OR-STRING specifies the new buffer or string that the extent should
+be in, and defaults to EXTENT's buffer or string. (If nil, and EXTENT
+is in no buffer and no string, it defaults to the current buffer.)
+See documentation on `detach-extent' for a discussion of undo recording.
+*/
+(extent, start, end, buffer_or_string))
+{
+EXTENT ext;
+Bytind s, e;
+ext = decode_extent (extent, 0);
+if (NILP (buffer_or_string))
+{
+buffer_or_string = extent_object (ext);
+if (NILP (buffer_or_string))
+	buffer_or_string = Fcurrent_buffer ();
+}
+else
+buffer_or_string = decode_buffer_or_string (buffer_or_string);
+if (NILP (start) && NILP (end))
+return Fdetach_extent (extent);
+get_buffer_or_string_range_byte (buffer_or_string, start, end, &s, &e,
+				   GB_ALLOW_PAST_ACCESSIBLE);
+set_extent_endpoints (ext, s, e, buffer_or_string);
+return extent;
+}
+/************************************************************************/
+/*		           mapping over extents				*/
+/************************************************************************/
+static unsigned int
+decode_map_extents_flags (Lisp_Object flags)
+{
+unsigned int retval = 0;
+unsigned int all_extents_specified = 0;
+unsigned int in_region_specified = 0;
+if (EQ (flags, Qt)) /* obsoleteness compatibility */
+return ME_END_CLOSED;
+if (NILP (flags))
+return 0;
+if (SYMBOLP (flags))
+flags = Fcons (flags, Qnil);
+while (!NILP (flags))
+{
+Lisp_Object sym;
+CHECK_CONS (flags);
+sym = XCAR (flags);
+CHECK_SYMBOL (sym);
+if (EQ (sym, Qall_extents_closed) || EQ (sym, Qall_extents_open) ||
+	  EQ (sym, Qall_extents_closed_open) ||
+	  EQ (sym, Qall_extents_open_closed))
+	{
+	  if (all_extents_specified)
+	    error ("Only one `all-extents-*' flag may be specified");
+	  all_extents_specified = 1;
+	}
+if (EQ (sym, Qstart_in_region) || EQ (sym, Qend_in_region) ||
+	  EQ (sym, Qstart_and_end_in_region) ||
+	  EQ (sym, Qstart_or_end_in_region))
+	{
+	  if (in_region_specified)
+	    error ("Only one `*-in-region' flag may be specified");
+	  in_region_specified = 1;
+	}
+/* I do so love that conditional operator ... */
+retval |=
+	EQ (sym, Qend_closed)		   ? ME_END_CLOSED :
+	EQ (sym, Qstart_open)		   ? ME_START_OPEN :
+	EQ (sym, Qall_extents_closed)	   ? ME_ALL_EXTENTS_CLOSED :
+	EQ (sym, Qall_extents_open)	   ? ME_ALL_EXTENTS_OPEN :
+	EQ (sym, Qall_extents_closed_open) ? ME_ALL_EXTENTS_CLOSED_OPEN :
+	EQ (sym, Qall_extents_open_closed) ? ME_ALL_EXTENTS_OPEN_CLOSED :
+	EQ (sym, Qstart_in_region)	   ? ME_START_IN_REGION :
+	EQ (sym, Qend_in_region)	   ? ME_END_IN_REGION :
+	EQ (sym, Qstart_and_end_in_region) ? ME_START_AND_END_IN_REGION :
+	EQ (sym, Qstart_or_end_in_region)  ? ME_START_OR_END_IN_REGION :
+	EQ (sym, Qnegate_in_region)	   ? ME_NEGATE_IN_REGION :
+	(signal_simple_error ("Invalid `map-extents' flag", sym), 0);
+flags = XCDR (flags);
+}
+return retval;
+}
+DEFUN ("extent-in-region-p", Fextent_in_region_p, 1, 4, 0, /*
+Return whether EXTENT overlaps a specified region.
+This is equivalent to whether `map-extents' would visit EXTENT when called
+with these args.
+*/
+(extent, from, to, flags))
+{
+Bytind start, end;
+EXTENT ext = decode_extent (extent, DE_MUST_BE_ATTACHED);
+Lisp_Object obj = extent_object (ext);
+get_buffer_or_string_range_byte (obj, from, to, &start, &end, GB_ALLOW_NIL |
+				   GB_ALLOW_PAST_ACCESSIBLE);
+return extent_in_region_p (ext, start, end, decode_map_extents_flags (flags)) ?
+Qt : Qnil;
+}
+struct slow_map_extents_arg
+{
+Lisp_Object map_arg;
+Lisp_Object map_routine;
+Lisp_Object result;
+Lisp_Object property;
+Lisp_Object value;
+};
+static int
+slow_map_extents_function (EXTENT extent, void *arg)
+{
+/* This function can GC */
+struct slow_map_extents_arg *closure = (struct slow_map_extents_arg *) arg;
+Lisp_Object extent_obj;
+XSETEXTENT (extent_obj, extent);
+/* make sure this extent qualifies according to the PROPERTY
+and VALUE args */
+if (!NILP (closure->property))
+{
+Lisp_Object value = Fextent_property (extent_obj, closure->property,
+					    Qnil);
+if ((NILP (closure->value) && NILP (value)) ||
+	  (!NILP (closure->value) && !EQ (value, closure->value)))
+	return 0;
+}
+closure->result = call2 (closure->map_routine, extent_obj,
+			   closure->map_arg);
+return !NILP (closure->result);
+}
+DEFUN ("map-extents", Fmap_extents, 1, 8, 0, /*
+Map FUNCTION over the extents which overlap a region in OBJECT.
+OBJECT is normally a buffer or string but could be an extent (see below).
+The region is normally bounded by [FROM, TO) (i.e. the beginning of the
+region is closed and the end of the region is open), but this can be
+changed with the FLAGS argument (see below for a complete discussion).
+FUNCTION is called with the arguments (extent, MAPARG).  The arguments
+OBJECT, FROM, TO, MAPARG, and FLAGS are all optional and default to
+the current buffer, the beginning of OBJECT, the end of OBJECT, nil,
+and nil, respectively.  `map-extents' returns the first non-nil result
+produced by FUNCTION, and no more calls to FUNCTION are made after it
+returns non-nil.
+If OBJECT is an extent, FROM and TO default to the extent's endpoints,
+and the mapping omits that extent and its predecessors.  This feature
+supports restarting a loop based on `map-extents'.  Note: OBJECT must
+be attached to a buffer or string, and the mapping is done over that
+buffer or string.
+An extent overlaps the region if there is any point in the extent that is
+also in the region. (For the purpose of overlap, zero-length extents and
+regions are treated as closed on both ends regardless of their endpoints'
+specified open/closedness.) Note that the endpoints of an extent or region
+are considered to be in that extent or region if and only if the
+corresponding end is closed.  For example, the extent [5,7] overlaps the
+region [2,5] because 5 is in both the extent and the region.  However, (5,7]
+does not overlap [2,5] because 5 is not in the extent, and neither [5,7] nor
+\(5,7] overlaps the region [2,5) because 5 is not in the region.
+The optional FLAGS can be a symbol or a list of one or more symbols,
+modifying the behavior of `map-extents'.  Allowed symbols are:
+end-closed		The region's end is closed.
+start-open		The region's start is open.
+all-extents-closed	Treat all extents as closed on both ends for the
+			purpose of determining whether they overlap the
+			region, irrespective of their actual open- or
+			closedness.
+all-extents-open	Treat all extents as open on both ends.
+all-extents-closed-open	Treat all extents as start-closed, end-open.
+all-extents-open-closed	Treat all extents as start-open, end-closed.
+start-in-region		In addition to the above conditions for extent
+			overlap, the extent's start position must lie within
+			the specified region.  Note that, for this
+			condition, open start positions are treated as if
+			0.5 was added to the endpoint's value, and open
+			end positions are treated as if 0.5 was subtracted
+			from the endpoint's value.
+end-in-region		The extent's end position must lie within the
+			region.
+start-and-end-in-region	Both the extent's start and end positions must lie
+			within the region.
+start-or-end-in-region	Either the extent's start or end position must lie
+			within the region.
+negate-in-region	The condition specified by a `*-in-region' flag
+			must NOT hold for the extent to be considered.
+At most one of `all-extents-closed', `all-extents-open',
+`all-extents-closed-open', and `all-extents-open-closed' may be specified.
+At most one of `start-in-region', `end-in-region',
+`start-and-end-in-region', and `start-or-end-in-region' may be specified.
+If optional arg PROPERTY is non-nil, only extents with that property set
+on them will be visited.  If optional arg VALUE is non-nil, only extents
+whose value for that property is `eq' to VALUE will be visited.
+*/
+(function, object, from, to, maparg, flags, property, value))
+{
+/* This function can GC */
+struct slow_map_extents_arg closure;
+unsigned int me_flags;
+Bytind start, end;
+struct gcpro gcpro1, gcpro2, gcpro3, gcpro4, gcpro5;
+EXTENT after = 0;
+if (EXTENTP (object))
+{
+after = decode_extent (object, DE_MUST_BE_ATTACHED);
+if (NILP (from))
+	from = Fextent_start_position (object);
+if (NILP (to))
+	to = Fextent_end_position (object);
+object = extent_object (after);
+}
+else
+object = decode_buffer_or_string (object);
+get_buffer_or_string_range_byte (object, from, to, &start, &end,
+				   GB_ALLOW_NIL | GB_ALLOW_PAST_ACCESSIBLE);
+me_flags = decode_map_extents_flags (flags);
+if (!NILP (property))
+{
+if (!NILP (value))
+	value =	canonicalize_extent_property (property, value);
+}
+GCPRO5 (function, maparg, object, property, value);
+closure.map_arg = maparg;
+closure.map_routine = function;
+closure.result = Qnil;
+closure.property = property;
+closure.value = value;
+map_extents_bytind (start, end, slow_map_extents_function,
+		      (void *) &closure, object, after,
+		      /* You never know what the user might do ... */
+		      me_flags | ME_MIGHT_CALL_ELISP);
+UNGCPRO;
+return closure.result;
+}
+/************************************************************************/
+/*		mapping over extents -- other functions			*/
+/************************************************************************/
+/* ------------------------------- */
+/*      map-extent-children        */
+/* ------------------------------- */
+struct slow_map_extent_children_arg
+{
+Lisp_Object map_arg;
+Lisp_Object map_routine;
+Lisp_Object result;
+Lisp_Object property;
+Lisp_Object value;
+Bytind start_min;
+Bytind prev_start;
+Bytind prev_end;
+};
+static int
+slow_map_extent_children_function (EXTENT extent, void *arg)
+{
+/* This function can GC */
+struct slow_map_extent_children_arg *closure =
+(struct slow_map_extent_children_arg *) arg;
+Lisp_Object extent_obj;
+Bytind start = extent_endpoint_bytind (extent, 0);
+Bytind end = extent_endpoint_bytind (extent, 1);
+/* Make sure the extent starts inside the region of interest,
+rather than just overlaps it.
+*/
+if (start < closure->start_min)
+return 0;
+/* Make sure the extent is not a child of a previous visited one.
+We know already, because of extent ordering,
+that start >= prev_start, and that if
+start == prev_start, then end <= prev_end.
+*/
+if (start == closure->prev_start)
+{
+if (end < closure->prev_end)
+	return 0;
+}
+else /* start > prev_start */
+{
+if (start < closure->prev_end)
+	return 0;
+/* corner case:  prev_end can be -1 if there is no prev */
+}
+XSETEXTENT (extent_obj, extent);
+/* make sure this extent qualifies according to the PROPERTY
+and VALUE args */
+if (!NILP (closure->property))
+{
+Lisp_Object value = Fextent_property (extent_obj, closure->property,
+					    Qnil);
+if ((NILP (closure->value) && NILP (value)) ||
+	  (!NILP (closure->value) && !EQ (value, closure->value)))
+	return 0;
+}
+closure->result = call2 (closure->map_routine, extent_obj,
+			   closure->map_arg);
+/* Since the callback may change the buffer, compute all stored
+buffer positions here.
+*/
+closure->start_min = -1;	/* no need for this any more */
+closure->prev_start = extent_endpoint_bytind (extent, 0);
+closure->prev_end = extent_endpoint_bytind (extent, 1);
+return !NILP (closure->result);
+}
+DEFUN ("map-extent-children", Fmap_extent_children, 1, 8, 0, /*
+Map FUNCTION over the extents in the region from FROM to TO.
+FUNCTION is called with arguments (extent, MAPARG).  See `map-extents'
+for a full discussion of the arguments FROM, TO, and FLAGS.
+The arguments are the same as for `map-extents', but this function differs
+in that it only visits extents which start in the given region, and also
+in that, after visiting an extent E, it skips all other extents which start
+inside E but end before E's end.
+Thus, this function may be used to walk a tree of extents in a buffer:
+	(defun walk-extents (buffer &optional ignore)
+	 (map-extent-children 'walk-extents buffer))
+*/
+(function, object, from, to, maparg, flags, property, value))
+{
+/* This function can GC */
+struct slow_map_extent_children_arg closure;
+unsigned int me_flags;
+Bytind start, end;
+struct gcpro gcpro1, gcpro2, gcpro3, gcpro4, gcpro5;
+EXTENT after = 0;
+if (EXTENTP (object))
+{
+after = decode_extent (object, DE_MUST_BE_ATTACHED);
+if (NILP (from))
+	from = Fextent_start_position (object);
+if (NILP (to))
+	to = Fextent_end_position (object);
+object = extent_object (after);
+}
+else
+object = decode_buffer_or_string (object);
+get_buffer_or_string_range_byte (object, from, to, &start, &end,
+				   GB_ALLOW_NIL | GB_ALLOW_PAST_ACCESSIBLE);
+me_flags = decode_map_extents_flags (flags);
+if (!NILP (property))
+{
+if (!NILP (value))
+	value =	canonicalize_extent_property (property, value);
+}
+GCPRO5 (function, maparg, object, property, value);
+closure.map_arg = maparg;
+closure.map_routine = function;
+closure.result = Qnil;
+closure.property = property;
+closure.value = value;
+closure.start_min = start;
+closure.prev_start = -1;
+closure.prev_end = -1;
+map_extents_bytind (start, end, slow_map_extent_children_function,
+		      (void *) &closure, object, after,
+		      /* You never know what the user might do ... */
+		      me_flags | ME_MIGHT_CALL_ELISP);
+UNGCPRO;
+return closure.result;
+}
+/* ------------------------------- */
+/*             extent-at           */
+/* ------------------------------- */
+/* find "smallest" matching extent containing pos -- (flag == 0) means
+all extents match, else (EXTENT_FLAGS (extent) & flag) must be true;
+for more than one matching extent with precisely the same endpoints,
+we choose the last extent in the extents_list.
+The search stops just before "before", if that is non-null.
+*/
+struct extent_at_arg
+{
+EXTENT best_match;
+Memind best_start;
+Memind best_end;
+Lisp_Object prop;
+EXTENT before;
+};
+enum extent_at_flag
+{
+EXTENT_AT_AFTER,
+EXTENT_AT_BEFORE,
+EXTENT_AT_AT
+};
+static enum extent_at_flag
+decode_extent_at_flag (Lisp_Object at_flag)
+{
+if (NILP (at_flag))
+return EXTENT_AT_AFTER;
+CHECK_SYMBOL (at_flag);
+if (EQ (at_flag, Qafter))  return EXTENT_AT_AFTER;
+if (EQ (at_flag, Qbefore)) return EXTENT_AT_BEFORE;
+if (EQ (at_flag, Qat))     return EXTENT_AT_AT;
+signal_simple_error ("Invalid AT-FLAG in `extent-at'", at_flag);
+return EXTENT_AT_AFTER; /* unreached */
+}
+static int
+extent_at_mapper (EXTENT e, void *arg)
+{
+struct extent_at_arg *closure = (struct extent_at_arg *) arg;
+if (e == closure->before)
+return 1;
+/* If closure->prop is non-nil, then the extent is only acceptable
+if it has a non-nil value for that property. */
+if (!NILP (closure->prop))
+{
+Lisp_Object extent;
+XSETEXTENT (extent, e);
+if (NILP (Fextent_property (extent, closure->prop, Qnil)))
+	return 0;
+}
+{
+EXTENT current = closure->best_match;
+if (!current)
+	goto accept;
+/* redundant but quick test */
+else if (extent_start (current) > extent_start (e))
+	return 0;
+/* we return the "last" best fit, instead of the first --
+	 this is because then the glyph closest to two equivalent
+	 extents corresponds to the "extent-at" the text just past
+	 that same glyph */
+else if (!EXTENT_LESS_VALS (e, closure->best_start,
+				  closure->best_end))
+goto accept;
+else
+	return 0;
+accept:
+closure->best_match = e;
+closure->best_start = extent_start (e);
+closure->best_end = extent_end (e);
+}
+return 0;
+}
+static Lisp_Object
+extent_at_bytind (Bytind position, Lisp_Object object, Lisp_Object property,
+		  EXTENT before, enum extent_at_flag at_flag)
+{
+struct extent_at_arg closure;
+Lisp_Object extent_obj;
+/* it might be argued that invalid positions should cause
+errors, but the principle of least surprise dictates that
+nil should be returned (extent-at is often used in
+response to a mouse event, and in many cases previous events
+have changed the buffer contents).
+Also, the openness stuff in the text-property code currently
+does not check its limits and might go off the end. */
+if ((at_flag == EXTENT_AT_BEFORE
+? position <= buffer_or_string_absolute_begin_byte (object)
+: position < buffer_or_string_absolute_begin_byte (object))
+|| (at_flag == EXTENT_AT_AFTER
+	  ? position >= buffer_or_string_absolute_end_byte (object)
+	  : position > buffer_or_string_absolute_end_byte (object)))
+return Qnil;
+closure.best_match = 0;
+closure.prop = property;
+closure.before = before;
+map_extents_bytind (at_flag == EXTENT_AT_BEFORE ? position - 1 : position,
+		      at_flag == EXTENT_AT_AFTER ? position + 1 : position,
+		      extent_at_mapper, (void *) &closure, object, 0,
+		      ME_START_OPEN | ME_ALL_EXTENTS_CLOSED);
+if (!closure.best_match)
+return Qnil;
+XSETEXTENT (extent_obj, closure.best_match);
+return extent_obj;
+}
+DEFUN ("extent-at", Fextent_at, 1, 5, 0, /*
+Find "smallest" extent at POS in OBJECT having PROPERTY set.
+Normally, an extent is "at" POS if it overlaps the region (POS, POS+1);
+i.e. if it covers the character after POS. (However, see the definition
+of AT-FLAG.) "Smallest" means the extent that comes last in the display
+order; this normally means the extent whose start position is closest to
+POS.  See `next-extent' for more information.
+OBJECT specifies a buffer or string and defaults to the current buffer.
+PROPERTY defaults to nil, meaning that any extent will do.
+Properties are attached to extents with `set-extent-property', which see.
+Returns nil if POS is invalid or there is no matching extent at POS.
+If the fourth argument BEFORE is not nil, it must be an extent; any returned
+extent will precede that extent.  This feature allows `extent-at' to be
+used by a loop over extents.
+AT-FLAG controls how end cases are handled, and should be one of:
+nil or `after'		An extent is at POS if it covers the character
+			after POS.  This is consistent with the way
+			that text properties work.
+`before'		An extent is at POS if it covers the character
+			before POS.
+`at'			An extent is at POS if it overlaps or abuts POS.
+			This includes all zero-length extents at POS.
+Note that in all cases, the start-openness and end-openness of the extents
+considered is ignored.  If you want to pay attention to those properties,
+you should use `map-extents', which gives you more control.
+*/
+(pos, object, property, before, at_flag))
+{
+Bytind position;
+EXTENT before_extent;
+enum extent_at_flag fl;
+object = decode_buffer_or_string (object);
+position = get_buffer_or_string_pos_byte (object, pos, GB_NO_ERROR_IF_BAD);
+if (NILP (before))
+before_extent = 0;
+else
+before_extent = decode_extent (before, DE_MUST_BE_ATTACHED);
+if (before_extent && !EQ (object, extent_object (before_extent)))
+signal_simple_error ("extent not in specified buffer or string", object);
+fl = decode_extent_at_flag (at_flag);
+return extent_at_bytind (position, object, property, before_extent, fl);
+}
+/* ------------------------------- */
+/*   verify_extent_modification()  */
+/* ------------------------------- */
+/* verify_extent_modification() is called when a buffer or string is
+modified to check whether the modification is occuring inside a
+read-only extent.
+*/
+struct verify_extents_arg
+{
+Lisp_Object object;
+Memind start;
+Memind end;
+Lisp_Object iro; /* value of inhibit-read-only */
+};
+static int
+verify_extent_mapper (EXTENT extent, void *arg)
+{
+struct verify_extents_arg *closure = (struct verify_extents_arg *) arg;
+Lisp_Object prop = extent_read_only (extent);
+if (NILP (prop))
+return 0;
+if (CONSP (closure->iro) && !NILP (Fmemq (prop, closure->iro)))
+return 0;
+#if 0 /* Nobody seems to care for this any more -sb */
+/* Allow deletion if the extent is completely contained in
+the region being deleted.
+This is important for supporting tokens which are internally
+write-protected, but which can be killed and yanked as a whole.
+Ignore open/closed distinctions at this point.
+-- Rose
+*/
+if (closure->start != closure->end &&
+extent_start (extent) >= closure->start &&
+extent_end (extent) <= closure->end)
+return 0;
+#endif
+while (1)
+Fsignal (Qbuffer_read_only, (list1 (closure->object)));
+RETURN_NOT_REACHED(0)
+}
+/* Value of Vinhibit_read_only is precomputed and passed in for
+efficiency */
+void
+verify_extent_modification (Lisp_Object object, Bytind from, Bytind to,
+			    Lisp_Object inhibit_read_only_value)
+{
+int closed;
+struct verify_extents_arg closure;
+/* If insertion, visit closed-endpoint extents touching the insertion
+point because the text would go inside those extents.  If deletion,
+treat the range as open on both ends so that touching extents are not
+visited.  Note that we assume that an insertion is occurring if the
+changed range has zero length, and a deletion otherwise.  This
+fails if a change (i.e. non-insertion, non-deletion) is happening.
+As far as I know, this doesn't currently occur in XEmacs. --ben */
+closed = (from==to);
+closure.object = object;
+closure.start = buffer_or_string_bytind_to_memind (object, from);
+closure.end = buffer_or_string_bytind_to_memind (object, to);
+closure.iro = inhibit_read_only_value;
+map_extents_bytind (from, to, verify_extent_mapper, (void *) &closure,
+		      object, 0, closed ? ME_END_CLOSED : ME_START_OPEN);
+}
+/* ------------------------------------ */
+/*    process_extents_for_insertion()   */
+/* ------------------------------------ */
+struct process_extents_for_insertion_arg
+{
+Bytind opoint;
+int length;
+Lisp_Object object;
+};
+/*   A region of length LENGTH was just inserted at OPOINT.  Modify all
+of the extents as required for the insertion, based on their
+start-open/end-open properties.
+*/
+static int
+process_extents_for_insertion_mapper (EXTENT extent, void *arg)
+{
+struct process_extents_for_insertion_arg *closure =
+(struct process_extents_for_insertion_arg *) arg;
+Memind indice = buffer_or_string_bytind_to_memind (closure->object,
+						      closure->opoint);
+/* When this function is called, one end of the newly-inserted text should
+be adjacent to some endpoint of the extent, or disjoint from it.  If
+the insertion overlaps any existing extent, something is wrong.
+*/
+#ifdef ERROR_CHECK_EXTENTS
+if (extent_start (extent) > indice &&
+extent_start (extent) < indice + closure->length)
+abort ();
+if (extent_end (extent) > indice &&
+extent_end (extent) < indice + closure->length)
+abort ();
+#endif
+/* The extent-adjustment code adjusted the extent's endpoints as if
+they were markers -- endpoints at the gap (i.e. the insertion
+point) go to the left of the insertion point, which is correct
+for [) extents.  We need to fix the other kinds of extents.
+Note that both conditions below will hold for zero-length (]
+extents at the gap.  Zero-length () extents would get adjusted
+such that their start is greater than their end; we treat them
+as [) extents.  This is unfortunately an inelegant part of the
+extent model, but there is no way around it. */
+{
+Memind new_start, new_end;
+new_start = extent_start (extent);
+new_end = extent_end (extent);
+if (indice == extent_start (extent) && extent_start_open_p (extent) &&
+	/* coerce zero-length () extents to [) */
+	new_start != new_end)
+new_start += closure->length;
+if (indice == extent_end (extent) && !extent_end_open_p (extent))
+new_end += closure->length;
+set_extent_endpoints_1 (extent, new_start, new_end);
+}
+return 0;
+}
+void
+process_extents_for_insertion (Lisp_Object object, Bytind opoint,
+			       Bytecount length)
+{
+struct process_extents_for_insertion_arg closure;
+closure.opoint = opoint;
+closure.length = length;
+closure.object = object;
+map_extents_bytind (opoint, opoint + length,
+		      process_extents_for_insertion_mapper,
+		      (void *) &closure, object, 0,
+		      ME_END_CLOSED | ME_MIGHT_MODIFY_EXTENTS |
+		      ME_INCLUDE_INTERNAL);
+}
+/* ------------------------------------ */
+/*    process_extents_for_deletion()    */
+/* ------------------------------------ */
+struct process_extents_for_deletion_arg
+{
+Memind start, end;
+int destroy_included_extents;
+};
+/* This function is called when we're about to delete the range [from, to].
+Detach all of the extents that are completely inside the range [from, to],
+if they're detachable or open-open. */
+static int
+process_extents_for_deletion_mapper (EXTENT extent, void *arg)
+{
+struct process_extents_for_deletion_arg *closure =
+(struct process_extents_for_deletion_arg *) arg;
+/* If the extent lies completely within the range that
+is being deleted, then nuke the extent if it's detachable
+(otherwise, it will become a zero-length extent). */
+if (closure->start <= extent_start (extent) &&
+extent_end (extent) <= closure->end)
+{
+if (extent_detachable_p (extent))
+	{
+	  if (closure->destroy_included_extents)
+	    destroy_extent (extent);
+	  else
+	    extent_detach (extent);
+	}
+}
+return 0;
+}
+/* DESTROY_THEM means destroy the extents instead of just deleting them.
+It is unused currently, but perhaps might be used (there used to
+be a function process_extents_for_destruction(), #if 0'd out,
+that did the equivalent). */
+void
+process_extents_for_deletion (Lisp_Object object, Bytind from,
+			      Bytind to, int destroy_them)
+{
+struct process_extents_for_deletion_arg closure;
+closure.start = buffer_or_string_bytind_to_memind (object, from);
+closure.end = buffer_or_string_bytind_to_memind (object, to);
+closure.destroy_included_extents = destroy_them;
+map_extents_bytind (from, to, process_extents_for_deletion_mapper,
+		      (void *) &closure, object, 0,
+		      ME_END_CLOSED | ME_MIGHT_MODIFY_EXTENTS);
+}
+/* ------------------------------- */
+/*   report_extent_modification()  */
+/* ------------------------------- */
+struct report_extent_modification_closure {
+Lisp_Object buffer;
+Bufpos start, end;
+int afterp;
+int speccount;
+};
+/* This juggling with the pointer to another file's global variable is
+kind of yucky.  Perhaps I should just export the variable.  */
+static int *inside_change_hook_pointer;
+static Lisp_Object
+report_extent_modification_restore (Lisp_Object buffer)
+{
+*inside_change_hook_pointer = 0;
+if (current_buffer != XBUFFER (buffer))
+Fset_buffer (buffer);
+return Qnil;
+}
+static int
+report_extent_modification_mapper (EXTENT extent, void *arg)
+{
+struct report_extent_modification_closure *closure =
+(struct report_extent_modification_closure *)arg;
+Lisp_Object exobj, startobj, endobj;
+Lisp_Object hook = (closure->afterp
+		      ? extent_after_change_functions (extent)
+		      : extent_before_change_functions (extent));
+if (NILP (hook))
+return 0;
+XSETEXTENT (exobj, extent);
+XSETINT (startobj, closure->start);
+XSETINT (endobj, closure->end);
+/* Now that we are sure to call elisp, set up an unwind-protect so
+inside_change_hook gets restored in case we throw.  Also record
+the current buffer, in case we change it.  Do the recording only
+once.  */
+if (closure->speccount == -1)
+{
+closure->speccount = specpdl_depth ();
+record_unwind_protect (report_extent_modification_restore,
+			     Fcurrent_buffer ());
+}
+/* The functions will expect closure->buffer to be the current
+buffer, so change it if it isn't.  */
+if (current_buffer != XBUFFER (closure->buffer))
+Fset_buffer (closure->buffer);
+/* #### It's a shame that we can't use any of the existing run_hook*
+functions here.  This is so because all of them work with
+symbols, to be able to retrieve default values of local hooks.
+<sigh> */
+if (!CONSP (hook) || EQ (XCAR (hook), Qlambda))
+call3 (hook, exobj, startobj, endobj);
+else
+{
+Lisp_Object tail;
+EXTERNAL_LIST_LOOP (tail, hook)
+	call3 (XCAR (tail), exobj, startobj, endobj);
+}
+return 0;
+}
+void
+report_extent_modification (Lisp_Object buffer, Bufpos start, Bufpos end,
+			    int *inside, int afterp)
+{
+struct report_extent_modification_closure closure;
+closure.buffer = buffer;
+closure.start = start;
+closure.end = end;
+closure.afterp = afterp;
+closure.speccount = -1;
+inside_change_hook_pointer = inside;
+*inside = 1;
+map_extents (start, end, report_extent_modification_mapper, (void *)&closure,
+	       buffer, NULL, ME_MIGHT_CALL_ELISP);
+if (closure.speccount == -1)
+*inside = 0;
+else
+{
+/* We mustn't unbind when closure.speccount != -1 because
+	 map_extents_bytind has already done that.  */
+assert (*inside == 0);
+}
+}
+/************************************************************************/
+/*		    	extent properties				*/
+/************************************************************************/
+static void
+set_extent_invisible (EXTENT extent, Lisp_Object value)
+{
+if (!EQ (extent_invisible (extent), value))
+{
+set_extent_invisible_1 (extent, value);
+extent_changed_for_redisplay (extent, 1, 1);
+}
+}
+/* This function does "memoization" -- similar to the interning
+that happens with symbols.  Given a list of faces, an equivalent
+list is returned such that if this function is called twice with
+input that is `equal', the resulting outputs will be `eq'.
+Note that the inputs and outputs are in general *not* `equal' --
+faces in symbol form become actual face objects in the output.
+This is necessary so that temporary faces stay around. */
+static Lisp_Object
+memoize_extent_face_internal (Lisp_Object list)
+{
+int len;
+int thelen;
+Lisp_Object cons, thecons;
+Lisp_Object oldtail, tail;
+struct gcpro gcpro1;
+if (NILP (list))
+return Qnil;
+if (!CONSP (list))
+return Fget_face (list);
+/* To do the memoization, we use a hash table mapping from
+external lists to internal lists.  We do `equal' comparisons
+on the keys so the memoization works correctly.
+Note that we canonicalize things so that the keys in the
+hash table (the external lists) always contain symbols and
+the values (the internal lists) always contain face objects.
+We also maintain a "reverse" table that maps from the internal
+lists to the external equivalents.  The idea here is twofold:
+1) `extent-face' wants to return a list containing face symbols
+rather than face objects.
+2) We don't want things to get quite so messed up if the user
+maliciously side-effects the returned lists.
+*/
+len = XINT (Flength (list));
+thelen = XINT (Flength (Vextent_face_reusable_list));
+oldtail = Qnil;
+tail = Qnil;
+GCPRO1 (oldtail);
+/* We canonicalize the given list into another list.
+We try to avoid consing except when necessary, so we have
+a reusable list.
+*/
+if (thelen < len)
+{
+cons = Vextent_face_reusable_list;
+while (!NILP (XCDR (cons)))
+	cons = XCDR (cons);
+XCDR (cons) = Fmake_list (make_int (len - thelen), Qnil);
+}
+else if (thelen > len)
+{
+int i;
+/* Truncate the list temporarily so it's the right length;
+	 remember the old tail. */
+cons = Vextent_face_reusable_list;
+for (i = 0; i < len - 1; i++)
+	cons = XCDR (cons);
+tail = cons;
+oldtail = XCDR (cons);
+XCDR (cons) = Qnil;
+}
+thecons = Vextent_face_reusable_list;
+EXTERNAL_LIST_LOOP (cons, list)
+{
+Lisp_Object face = Fget_face (XCAR (cons));
+XCAR (thecons) = Fface_name (face);
+thecons = XCDR (thecons);
+}
+list = Fgethash (Vextent_face_reusable_list, Vextent_face_memoize_hash_table,
+		   Qnil);
+if (NILP (list))
+{
+Lisp_Object symlist = Fcopy_sequence (Vextent_face_reusable_list);
+Lisp_Object facelist = Fcopy_sequence (Vextent_face_reusable_list);
+LIST_LOOP (cons, facelist)
+	{
+	  XCAR (cons) = Fget_face (XCAR (cons));
+	}
+Fputhash (symlist, facelist, Vextent_face_memoize_hash_table);
+Fputhash (facelist, symlist, Vextent_face_reverse_memoize_hash_table);
+list = facelist;
+}
+/* Now restore the truncated tail of the reusable list, if necessary. */
+if (!NILP (tail))
+XCDR (tail) = oldtail;
+UNGCPRO;
+return list;
+}
+static Lisp_Object
+external_of_internal_memoized_face (Lisp_Object face)
+{
+if (NILP (face))
+return Qnil;
+else if (!CONSP (face))
+return XFACE (face)->name;
+else
+{
+face = Fgethash (face, Vextent_face_reverse_memoize_hash_table,
+		       Qunbound);
+assert (!UNBOUNDP (face));
+return face;
+}
+}
+static Lisp_Object
+canonicalize_extent_property (Lisp_Object prop, Lisp_Object value)
+{
+if (EQ (prop, Qface) || EQ (prop, Qmouse_face))
+value = (external_of_internal_memoized_face
+	     (memoize_extent_face_internal (value)));
+return value;
+}
+/* Do we need a lisp-level function ? */
+DEFUN ("set-extent-initial-redisplay-function", Fset_extent_initial_redisplay_function,
+2,2,0,/*
+Note: This feature is experimental!
+Set initial-redisplay-function of EXTENT to the function
+FUNCTION.
+The first time the EXTENT is (re)displayed, an eval event will be
+dispatched calling FUNCTION with EXTENT as its only argument.
+*/
+(extent, function))
+{
+EXTENT e = decode_extent(extent, DE_MUST_BE_ATTACHED);
+e = extent_ancestor (e);  /* Is this needed? Macro also does chasing!*/
+set_extent_initial_redisplay_function(e,function);
+extent_in_red_event_p(e) = 0;  /* If the function changed we can spawn
+				    new events */
+extent_changed_for_redisplay(e,1,0); /* Do we need to mark children too ?*/
+return function;
+}
+DEFUN ("extent-face", Fextent_face, 1, 1, 0, /*
+Return the name of the face in which EXTENT is displayed, or nil
+if the extent's face is unspecified.  This might also return a list
+of face names.
+*/
+(extent))
+{
+Lisp_Object face;
+CHECK_EXTENT (extent);
+face = extent_face (XEXTENT (extent));
+return external_of_internal_memoized_face (face);
+}
+DEFUN ("set-extent-face", Fset_extent_face, 2, 2, 0, /*
+Make the given EXTENT have the graphic attributes specified by FACE.
+FACE can also be a list of faces, and all faces listed will apply,
+with faces earlier in the list taking priority over those later in the
+list.
+*/
+(extent, face))
+{
+EXTENT e = decode_extent(extent, 0);
+Lisp_Object orig_face = face;
+/* retrieve the ancestor for efficiency and proper redisplay noting. */
+e = extent_ancestor (e);
+face = memoize_extent_face_internal (face);
+extent_face (e) = face;
+extent_changed_for_redisplay (e, 1, 0);
+return orig_face;
+}
+DEFUN ("extent-mouse-face", Fextent_mouse_face, 1, 1, 0, /*
+Return the face used to highlight EXTENT when the mouse passes over it.
+The return value will be a face name, a list of face names, or nil
+if the extent's mouse face is unspecified.
+*/
+(extent))
+{
+Lisp_Object face;
+CHECK_EXTENT (extent);
+face = extent_mouse_face (XEXTENT (extent));
+return external_of_internal_memoized_face (face);
+}
+DEFUN ("set-extent-mouse-face", Fset_extent_mouse_face, 2, 2, 0, /*
+Set the face used to highlight EXTENT when the mouse passes over it.
+FACE can also be a list of faces, and all faces listed will apply,
+with faces earlier in the list taking priority over those later in the
+list.
+*/
+(extent, face))
+{
+EXTENT e;
+Lisp_Object orig_face = face;
+CHECK_EXTENT (extent);
+e = XEXTENT (extent);
+/* retrieve the ancestor for efficiency and proper redisplay noting. */
+e = extent_ancestor (e);
+face = memoize_extent_face_internal (face);
+set_extent_mouse_face (e, face);
+extent_changed_for_redisplay (e, 1, 0);
+return orig_face;
+}
+void
+set_extent_glyph (EXTENT extent, Lisp_Object glyph, int endp,
+		  glyph_layout layout)
+{
+extent = extent_ancestor (extent);
+if (!endp)
+{
+set_extent_begin_glyph (extent, glyph);
+extent_begin_glyph_layout (extent) = layout;
+}
+else
+{
+set_extent_end_glyph (extent, glyph);
+extent_end_glyph_layout (extent) = layout;
+}
+extent_changed_for_redisplay (extent, 1, 0);
+}
+static Lisp_Object
+glyph_layout_to_symbol (glyph_layout layout)
+{
+switch (layout)
+{
+case GL_TEXT:	    return Qtext;
+case GL_OUTSIDE_MARGIN: return Qoutside_margin;
+case GL_INSIDE_MARGIN:  return Qinside_margin;
+case GL_WHITESPACE:	    return Qwhitespace;
+default:
+abort ();
+return Qnil; /* unreached */
+}
+}
+static glyph_layout
+symbol_to_glyph_layout (Lisp_Object layout_obj)
+{
+if (NILP (layout_obj))
+return GL_TEXT;
+CHECK_SYMBOL (layout_obj);
+if (EQ (layout_obj, Qoutside_margin)) return GL_OUTSIDE_MARGIN;
+if (EQ (layout_obj, Qinside_margin))	return GL_INSIDE_MARGIN;
+if (EQ (layout_obj, Qwhitespace))	return GL_WHITESPACE;
+if (EQ (layout_obj, Qtext))		return GL_TEXT;
+signal_simple_error ("Unknown glyph layout type", layout_obj);
+return GL_TEXT; /* unreached */
+}
+static Lisp_Object
+set_extent_glyph_1 (Lisp_Object extent_obj, Lisp_Object glyph, int endp,
+		    Lisp_Object layout_obj)
+{
+EXTENT extent = decode_extent (extent_obj, DE_MUST_HAVE_BUFFER);
+glyph_layout layout = symbol_to_glyph_layout (layout_obj);
+/* Make sure we've actually been given a valid glyph or it's nil
+(meaning we're deleting a glyph from an extent). */
+if (!NILP (glyph))
+CHECK_BUFFER_GLYPH (glyph);
+set_extent_glyph (extent, glyph, endp, layout);
+return glyph;
+}
+DEFUN ("set-extent-begin-glyph", Fset_extent_begin_glyph, 2, 3, 0, /*
+Display a bitmap, subwindow or string at the beginning of EXTENT.
+BEGIN-GLYPH must be a glyph object.  The layout policy defaults to `text'.
+*/
+(extent, begin_glyph, layout))
+{
+return set_extent_glyph_1 (extent, begin_glyph, 0, layout);
+}
+DEFUN ("set-extent-end-glyph", Fset_extent_end_glyph, 2, 3, 0, /*
+Display a bitmap, subwindow or string at the end of EXTENT.
+END-GLYPH must be a glyph object.  The layout policy defaults to `text'.
+*/
+(extent, end_glyph, layout))
+{
+return set_extent_glyph_1 (extent, end_glyph, 1, layout);
+}
+DEFUN ("extent-begin-glyph", Fextent_begin_glyph, 1, 1, 0, /*
+Return the glyph object displayed at the beginning of EXTENT.
+If there is none, nil is returned.
+*/
+(extent))
+{
+return extent_begin_glyph (decode_extent (extent, 0));
+}
+DEFUN ("extent-end-glyph", Fextent_end_glyph, 1, 1, 0, /*
+Return the glyph object displayed at the end of EXTENT.
+If there is none, nil is returned.
+*/
+(extent))
+{
+return extent_end_glyph (decode_extent (extent, 0));
+}
+DEFUN ("set-extent-begin-glyph-layout", Fset_extent_begin_glyph_layout, 2, 2, 0, /*
+Set the layout policy of EXTENT's begin glyph.
+Access this using the `extent-begin-glyph-layout' function.
+*/
+(extent, layout))
+{
+EXTENT e = decode_extent (extent, 0);
+e = extent_ancestor (e);
+extent_begin_glyph_layout (e) = symbol_to_glyph_layout (layout);
+extent_maybe_changed_for_redisplay (e, 1, 0);
+return layout;
+}
+DEFUN ("set-extent-end-glyph-layout", Fset_extent_end_glyph_layout, 2, 2, 0, /*
+Set the layout policy of EXTENT's end glyph.
+Access this using the `extent-end-glyph-layout' function.
+*/
+(extent, layout))
+{
+EXTENT e = decode_extent (extent, 0);
+e = extent_ancestor (e);
+extent_end_glyph_layout (e) = symbol_to_glyph_layout (layout);
+extent_maybe_changed_for_redisplay (e, 1, 0);
+return layout;
+}
+DEFUN ("extent-begin-glyph-layout", Fextent_begin_glyph_layout, 1, 1, 0, /*
+Return the layout policy associated with EXTENT's begin glyph.
+Set this using the `set-extent-begin-glyph-layout' function.
+*/
+(extent))
+{
+EXTENT e = decode_extent (extent, 0);
+return glyph_layout_to_symbol ((glyph_layout) extent_begin_glyph_layout (e));
+}
+DEFUN ("extent-end-glyph-layout", Fextent_end_glyph_layout, 1, 1, 0, /*
+Return the layout policy associated with EXTENT's end glyph.
+Set this using the `set-extent-end-glyph-layout' function.
+*/
+(extent))
+{
+EXTENT e = decode_extent (extent, 0);
+return glyph_layout_to_symbol ((glyph_layout) extent_end_glyph_layout (e));
+}
+DEFUN ("set-extent-priority", Fset_extent_priority, 2, 2, 0, /*
+Set the display priority of EXTENT to PRIORITY (an integer).
+When the extent attributes are being merged for display, the priority
+is used to determine which extent takes precedence in the event of a
+conflict (two extents whose faces both specify font, for example: the
+font of the extent with the higher priority will be used).
+Extents are created with priority 0; priorities may be negative.
+*/
+(extent, priority))
+{
+EXTENT e = decode_extent (extent, 0);
+CHECK_INT (priority);
+e = extent_ancestor (e);
+set_extent_priority (e, XINT (priority));
+extent_maybe_changed_for_redisplay (e, 1, 0);
+return priority;
+}
+DEFUN ("extent-priority", Fextent_priority, 1, 1, 0, /*
+Return the display priority of EXTENT; see `set-extent-priority'.
+*/
+(extent))
+{
+EXTENT e = decode_extent (extent, 0);
+return make_int (extent_priority (e));
+}
+DEFUN ("set-extent-property", Fset_extent_property, 3, 3, 0, /*
+Change a property of an extent.
+PROPERTY may be any symbol; the value stored may be accessed with
+the `extent-property' function.
+The following symbols have predefined meanings:
+detached           Removes the extent from its buffer; setting this is
+the same as calling `detach-extent'.
+destroyed          Removes the extent from its buffer, and makes it
+unusable in the future; this is the same calling
+`delete-extent'.
+priority           Change redisplay priority; same as `set-extent-priority'.
+start-open         Whether the set of characters within the extent is
+treated being open on the left, that is, whether
+the start position is an exclusive, rather than
+inclusive, boundary.  If true, then characters
+inserted exactly at the beginning of the extent
+will remain outside of the extent; otherwise they
+will go into the extent, extending it.
+end-open           Whether the set of characters within the extent is
+treated being open on the right, that is, whether
+the end position is an exclusive, rather than
+inclusive, boundary.  If true, then characters
+inserted exactly at the end of the extent will
+remain outside of the extent; otherwise they will
+go into the extent, extending it.
+By default, extents have the `end-open' but not the
+`start-open' property set.
+read-only          Text within this extent will be unmodifiable.
+initial-redisplay-function (EXPERIMENTAL)
+function to be called the first time (part of) the extent
+is redisplayed. It will be called with the extent as its
+first argument.
+		    Note: The function will not be called immediately
+		    during redisplay, an eval event will be dispatched.
+detachable         Whether the extent gets detached (as with
+`detach-extent') when all the text within the
+extent is deleted.  This is true by default.  If
+this property is not set, the extent becomes a
+zero-length extent when its text is deleted. (In
+such a case, the `start-open' property is
+automatically removed if both the `start-open' and
+`end-open' properties are set, since zero-length
+extents open on both ends are not allowed.)
+face               The face in which to display the text.  Setting
+this is the same as calling `set-extent-face'.
+mouse-face	    If non-nil, the extent will be highlighted in this
+		    face when the mouse moves over it.
+pointer            If non-nil, and a valid pointer glyph, this specifies
+the shape of the mouse pointer while over the extent.
+highlight          Obsolete: Setting this property is equivalent to
+		    setting a `mouse-face' property of `highlight'.
+		    Reading this property returns non-nil if
+		    the extent has a non-nil `mouse-face' property.
+duplicable         Whether this extent should be copied into strings,
+so that kill, yank, and undo commands will restore
+or copy it.  `duplicable' extents are copied from
+an extent into a string when `buffer-substring' or
+a similar function creates a string.  The extents
+in a string are copied into other strings created
+from the string using `concat' or `substring'.
+When `insert' or a similar function inserts the
+string into a buffer, the extents are copied back
+into the buffer.
+unique             Meaningful only in conjunction with `duplicable'.
+When this is set, there may be only one instance
+of this extent attached at a time: if it is copied
+to the kill ring and then yanked, the extent is
+not copied.  If, however, it is killed (removed
+from the buffer) and then yanked, it will be
+re-attached at the new position.
+invisible          If the value is non-nil, text under this extent
+may be treated as not present for the purpose of
+redisplay, or may be displayed using an ellipsis
+or other marker; see `buffer-invisibility-spec'
+and `invisible-text-glyph'.  In all cases,
+however, the text is still visible to other
+functions that examine a buffer's text.
+keymap             This keymap is consulted for mouse clicks on this
+extent, or keypresses made while point is within the
+extent.
+copy-function      This is a hook that is run when a duplicable extent
+is about to be copied from a buffer to a string (or
+the kill ring).  It is called with three arguments,
+the extent, and the buffer-positions within it
+which are being copied.  If this function returns
+nil, then the extent will not be copied; otherwise
+it will.
+paste-function     This is a hook that is run when a duplicable extent is
+about to be copied from a string (or the kill ring)
+into a buffer.  It is called with three arguments,
+the original extent, and the buffer positions which
+the copied extent will occupy.  (This hook is run
+after the corresponding text has already been
+inserted into the buffer.)  Note that the extent
+argument may be detached when this function is run.
+If this function returns nil, no extent will be
+inserted.  Otherwise, there will be an extent
+covering the range in question.
+If the original extent is not attached to a buffer,
+then it will be re-attached at this range.
+Otherwise, a copy will be made, and that copy
+attached here.
+The copy-function and paste-function are meaningful
+only for extents with the `duplicable' flag set,
+and if they are not specified, behave as if `t' was
+the returned value.  When these hooks are invoked,
+the current buffer is the buffer which the extent
+is being copied from/to, respectively.
+begin-glyph        A glyph to be displayed at the beginning of the extent,
+or nil.
+end-glyph          A glyph to be displayed at the end of the extent,
+or nil.
+begin-glyph-layout The layout policy (one of `text', `whitespace',
+`inside-margin', or `outside-margin') of the extent's
+begin glyph.
+end-glyph-layout The layout policy of the extent's end glyph.
+*/
+(extent, property, value))
+{
+/* This function can GC if property is `keymap' */
+EXTENT e = decode_extent (extent, 0);
+if (EQ (property, Qread_only))
+set_extent_read_only (e, value);
+else if (EQ (property, Qunique))
+extent_unique_p (e) = !NILP (value);
+else if (EQ (property, Qduplicable))
+extent_duplicable_p (e) = !NILP (value);
+else if (EQ (property, Qinvisible))
+set_extent_invisible (e, value);
+else if (EQ (property, Qdetachable))
+extent_detachable_p (e) = !NILP (value);
+else if (EQ (property, Qdetached))
+{
+if (NILP (value))
+	error ("can only set `detached' to t");
+Fdetach_extent (extent);
+}
+else if (EQ (property, Qdestroyed))
+{
+if (NILP (value))
+	error ("can only set `destroyed' to t");
+Fdelete_extent (extent);
+}
+else if (EQ (property, Qpriority))
+Fset_extent_priority (extent, value);
+else if (EQ (property, Qface))
+Fset_extent_face (extent, value);
+else if (EQ (property, Qinitial_redisplay_function))
+Fset_extent_initial_redisplay_function (extent, value);
+else if (EQ (property, Qbefore_change_functions))
+set_extent_before_change_functions (e, value);
+else if (EQ (property, Qafter_change_functions))
+set_extent_after_change_functions (e, value);
+else if (EQ (property, Qmouse_face))
+Fset_extent_mouse_face (extent, value);
+/* Obsolete: */
+else if (EQ (property, Qhighlight))
+Fset_extent_mouse_face (extent, Qhighlight);
+else if (EQ (property, Qbegin_glyph_layout))
+Fset_extent_begin_glyph_layout (extent, value);
+else if (EQ (property, Qend_glyph_layout))
+Fset_extent_end_glyph_layout (extent, value);
+/* For backwards compatibility.  We use begin glyph because it is by
+far the more used of the two. */
+else if (EQ (property, Qglyph_layout))
+Fset_extent_begin_glyph_layout (extent, value);
+else if (EQ (property, Qbegin_glyph))
+Fset_extent_begin_glyph (extent, value, Qnil);
+else if (EQ (property, Qend_glyph))
+Fset_extent_end_glyph (extent, value, Qnil);
+else if (EQ (property, Qstart_open))
+set_extent_openness (e, !NILP (value), -1);
+else if (EQ (property, Qend_open))
+set_extent_openness (e, -1, !NILP (value));
+/* Support (but don't document...) the obvious *_closed antonyms. */
+else if (EQ (property, Qstart_closed))
+set_extent_openness (e, NILP (value), -1);
+else if (EQ (property, Qend_closed))
+set_extent_openness (e, -1, NILP (value));
+else
+{
+if (EQ (property, Qkeymap))
+	while (!NILP (value) && NILP (Fkeymapp (value)))
+	  value = wrong_type_argument (Qkeymapp, value);
+external_plist_put (extent_plist_addr (e), property, value, 0, ERROR_ME);
+}
+return value;
+}
+DEFUN ("set-extent-properties", Fset_extent_properties, 2, 2, 0, /*
+Change some properties of EXTENT.
+PLIST is a property list.
+For a list of built-in properties, see `set-extent-property'.
+*/
+(extent, plist))
+{
+/* This function can GC, if one of the properties is `keymap' */
+Lisp_Object property, value;
+struct gcpro gcpro1;
+GCPRO1 (plist);
+plist = Fcopy_sequence (plist);
+Fcanonicalize_plist (plist, Qnil);
+while (!NILP (plist))
+{
+property = Fcar (plist); plist = Fcdr (plist);
+value    = Fcar (plist); plist = Fcdr (plist);
+Fset_extent_property (extent, property, value);
+}
+UNGCPRO;
+return Qnil;
+}
+DEFUN ("extent-property", Fextent_property, 2, 3, 0, /*
+Return EXTENT's value for property PROPERTY.
+See `set-extent-property' for the built-in property names.
+*/
+(extent, property, default_))
+{
+EXTENT e = decode_extent (extent, 0);
+if (EQ (property, Qdetached))
+return extent_detached_p (e) ? Qt : Qnil;
+else if (EQ (property, Qdestroyed))
+return !EXTENT_LIVE_P (e) ? Qt : Qnil;
+else if (EQ (property, Qstart_open))
+return extent_normal_field (e, start_open) ? Qt : Qnil;
+else if (EQ (property, Qend_open))
+return extent_normal_field (e, end_open) ? Qt : Qnil;
+else if (EQ (property, Qunique))
+return extent_normal_field (e, unique) ? Qt : Qnil;
+else if (EQ (property, Qduplicable))
+return extent_normal_field (e, duplicable) ? Qt : Qnil;
+else if (EQ (property, Qdetachable))
+return extent_normal_field (e, detachable) ? Qt : Qnil;
+/* Support (but don't document...) the obvious *_closed antonyms. */
+else if (EQ (property, Qstart_closed))
+return extent_start_open_p (e) ? Qnil : Qt;
+else if (EQ (property, Qend_closed))
+return extent_end_open_p (e) ? Qnil : Qt;
+else if (EQ (property, Qpriority))
+return make_int (extent_priority (e));
+else if (EQ (property, Qread_only))
+return extent_read_only (e);
+else if (EQ (property, Qinvisible))
+return extent_invisible (e);
+else if (EQ (property, Qface))
+return Fextent_face (extent);
+else if (EQ (property, Qinitial_redisplay_function))
+return extent_initial_redisplay_function (e);
+else if (EQ (property, Qbefore_change_functions))
+return extent_before_change_functions (e);
+else if (EQ (property, Qafter_change_functions))
+return extent_after_change_functions (e);
+else if (EQ (property, Qmouse_face))
+return Fextent_mouse_face (extent);
+/* Obsolete: */
+else if (EQ (property, Qhighlight))
+return !NILP (Fextent_mouse_face (extent)) ? Qt : Qnil;
+else if (EQ (property, Qbegin_glyph_layout))
+return Fextent_begin_glyph_layout (extent);
+else if (EQ (property, Qend_glyph_layout))
+return Fextent_end_glyph_layout (extent);
+/* For backwards compatibility.  We use begin glyph because it is by
+far the more used of the two. */
+else if (EQ (property, Qglyph_layout))
+return Fextent_begin_glyph_layout (extent);
+else if (EQ (property, Qbegin_glyph))
+return extent_begin_glyph (e);
+else if (EQ (property, Qend_glyph))
+return extent_end_glyph (e);
+else
+{
+Lisp_Object value = external_plist_get (extent_plist_addr (e),
+					      property, 0, ERROR_ME);
+return UNBOUNDP (value) ? default_ : value;
+}
+}
+DEFUN ("extent-properties", Fextent_properties, 1, 1, 0, /*
+Return a property list of the attributes of EXTENT.
+Do not modify this list; use `set-extent-property' instead.
+*/
+(extent))
+{
+EXTENT e, anc;
+Lisp_Object result, face, anc_obj;
+glyph_layout layout;
+CHECK_EXTENT (extent);
+e = XEXTENT (extent);
+if (!EXTENT_LIVE_P (e))
+return cons3 (Qdestroyed, Qt, Qnil);
+anc = extent_ancestor (e);
+XSETEXTENT (anc_obj, anc);
+/* For efficiency, use the ancestor for all properties except detached */
+result = extent_plist_slot (anc);
+if (!NILP (face = Fextent_face (anc_obj)))
+result = cons3 (Qface, face, result);
+if (!NILP (face = Fextent_mouse_face (anc_obj)))
+result = cons3 (Qmouse_face, face, result);
+if ((layout = (glyph_layout) extent_begin_glyph_layout (anc)) != GL_TEXT)
+{
+Lisp_Object sym = glyph_layout_to_symbol (layout);
+result = cons3 (Qglyph_layout,       sym, result); /* compatibility */
+result = cons3 (Qbegin_glyph_layout, sym, result);
+}
+if ((layout = (glyph_layout) extent_end_glyph_layout (anc)) != GL_TEXT)
+result = cons3 (Qend_glyph_layout, glyph_layout_to_symbol (layout), result);
+if (!NILP (extent_end_glyph (anc)))
+result = cons3 (Qend_glyph, extent_end_glyph (anc), result);
+if (!NILP (extent_begin_glyph (anc)))
+result = cons3 (Qbegin_glyph, extent_begin_glyph (anc), result);
+if (extent_priority (anc) != 0)
+result = cons3 (Qpriority, make_int (extent_priority (anc)), result);
+if (!NILP (extent_initial_redisplay_function (anc)))
+result = cons3 (Qinitial_redisplay_function,
+		    extent_initial_redisplay_function (anc), result);
+if (!NILP (extent_before_change_functions (anc)))
+result = cons3 (Qbefore_change_functions,
+		    extent_before_change_functions (anc), result);
+if (!NILP (extent_after_change_functions (anc)))
+result = cons3 (Qafter_change_functions,
+		    extent_after_change_functions (anc), result);
+if (!NILP (extent_invisible (anc)))
+result = cons3 (Qinvisible, extent_invisible (anc), result);
+if (!NILP (extent_read_only (anc)))
+result = cons3 (Qread_only, extent_read_only (anc), result);
+if  (extent_normal_field (anc, end_open))
+result = cons3 (Qend_open, Qt, result);
+if  (extent_normal_field (anc, start_open))
+result = cons3 (Qstart_open, Qt, result);
+if  (extent_normal_field (anc, detachable))
+result = cons3 (Qdetachable, Qt, result);
+if  (extent_normal_field (anc, duplicable))
+result = cons3 (Qduplicable, Qt, result);
+if  (extent_normal_field (anc, unique))
+result = cons3 (Qunique, Qt, result);
+/* detached is not an inherited property */
+if (extent_detached_p (e))
+result = cons3 (Qdetached, Qt, result);
+return result;
+}
+/************************************************************************/
+/*		    	     highlighting      				*/
+/************************************************************************/
+/* The display code looks into the Vlast_highlighted_extent variable to
+correctly display highlighted extents.  This updates that variable,
+and marks the appropriate buffers as needing some redisplay.
+*/
+static void
+do_highlight (Lisp_Object extent_obj, int highlight_p)
+{
+if (( highlight_p && (EQ (Vlast_highlighted_extent, extent_obj))) ||
+(!highlight_p && (EQ (Vlast_highlighted_extent, Qnil))))
+return;
+if (EXTENTP (Vlast_highlighted_extent) &&
+EXTENT_LIVE_P (XEXTENT (Vlast_highlighted_extent)))
+{
+/* do not recurse on descendants.  Only one extent is highlighted
+	 at a time. */
+extent_changed_for_redisplay (XEXTENT (Vlast_highlighted_extent), 0, 0);
+}
+Vlast_highlighted_extent = Qnil;
+if (!NILP (extent_obj)
+&& BUFFERP (extent_object (XEXTENT (extent_obj)))
+&& highlight_p)
+{
+extent_changed_for_redisplay (XEXTENT (extent_obj), 0, 0);
+Vlast_highlighted_extent = extent_obj;
+}
+}
+DEFUN ("force-highlight-extent", Fforce_highlight_extent, 1, 2, 0, /*
+Highlight or unhighlight the given extent.
+If the second arg is non-nil, it will be highlighted, else dehighlighted.
+This is the same as `highlight-extent', except that it will work even
+on extents without the `mouse-face' property.
+*/
+(extent, highlight_p))
+{
+if (NILP (extent))
+highlight_p = Qnil;
+else
+XSETEXTENT (extent, decode_extent (extent, DE_MUST_BE_ATTACHED));
+do_highlight (extent, !NILP (highlight_p));
+return Qnil;
+}
+DEFUN ("highlight-extent", Fhighlight_extent, 1, 2, 0, /*
+Highlight EXTENT, if it is highlightable.
+\(that is, if it has the `mouse-face' property).
+If the second arg is non-nil, it will be highlighted, else dehighlighted.
+Highlighted extents are displayed as if they were merged with the face
+or faces specified by the `mouse-face' property.
+*/
+(extent, highlight_p))
+{
+if (EXTENTP (extent) && NILP (extent_mouse_face (XEXTENT (extent))))
+return Qnil;
+else
+return Fforce_highlight_extent (extent, highlight_p);
+}
+/************************************************************************/
+/*			   strings and extents				*/
+/************************************************************************/
+/* copy/paste hooks */
+static int
+run_extent_copy_paste_internal (EXTENT e, Bufpos from, Bufpos to,
+				Lisp_Object object,
+				Lisp_Object prop)
+{
+/* This function can GC */
+Lisp_Object extent;
+Lisp_Object copy_fn;
+XSETEXTENT (extent, e);
+copy_fn = Fextent_property (extent, prop, Qnil);
+if (!NILP (copy_fn))
+{
+Lisp_Object flag;
+struct gcpro gcpro1, gcpro2, gcpro3;
+GCPRO3 (extent, copy_fn, object);
+if (BUFFERP (object))
+	flag = call3_in_buffer (XBUFFER (object), copy_fn, extent,
+				make_int (from), make_int (to));
+else
+	flag = call3 (copy_fn, extent, make_int (from), make_int (to));
+UNGCPRO;
+if (NILP (flag) || !EXTENT_LIVE_P (XEXTENT (extent)))
+	return 0;
+}
+return 1;
+}
+static int
+run_extent_copy_function (EXTENT e, Bytind from, Bytind to)
+{
+Lisp_Object object = extent_object (e);
+/* This function can GC */
+return run_extent_copy_paste_internal
+(e, buffer_or_string_bytind_to_bufpos (object, from),
+buffer_or_string_bytind_to_bufpos (object, to), object,
+Qcopy_function);
+}
+static int
+run_extent_paste_function (EXTENT e, Bytind from, Bytind to,
+			   Lisp_Object object)
+{
+/* This function can GC */
+return run_extent_copy_paste_internal
+(e, buffer_or_string_bytind_to_bufpos (object, from),
+buffer_or_string_bytind_to_bufpos (object, to), object,
+Qpaste_function);
+}
+static void
+update_extent (EXTENT extent, Bytind from, Bytind to)
+{
+set_extent_endpoints (extent, from, to, Qnil);
+}
+/* Insert an extent, usually from the dup_list of a string which
+has just been inserted.
+This code does not handle the case of undo.
+*/
+static Lisp_Object
+insert_extent (EXTENT extent, Bytind new_start, Bytind new_end,
+	       Lisp_Object object, int run_hooks)
+{
+/* This function can GC */
+Lisp_Object tmp;
+if (!EQ (extent_object (extent), object))
+goto copy_it;
+if (extent_detached_p (extent))
+{
+if (run_hooks &&
+	  !run_extent_paste_function (extent, new_start, new_end, object))
+	/* The paste-function said don't re-attach this extent here. */
+	return Qnil;
+else
+	update_extent (extent, new_start, new_end);
+}
+else
+{
+Bytind exstart = extent_endpoint_bytind (extent, 0);
+Bytind exend = extent_endpoint_bytind (extent, 1);
+if (exend < new_start || exstart > new_end)
+	goto copy_it;
+else
+	{
+	  new_start = min (exstart, new_start);
+	  new_end = max (exend, new_end);
+	  if (exstart != new_start || exend != new_end)
+	    update_extent (extent, new_start, new_end);
+	}
+}
+XSETEXTENT (tmp, extent);
+return tmp;
+copy_it:
+if (run_hooks &&
+!run_extent_paste_function (extent, new_start, new_end, object))
+/* The paste-function said don't attach a copy of the extent here. */
+return Qnil;
+else
+{
+XSETEXTENT (tmp, copy_extent (extent, new_start, new_end, object));
+return tmp;
+}
+}
+DEFUN ("insert-extent", Finsert_extent, 1, 5, 0, /*
+Insert EXTENT from START to END in BUFFER-OR-STRING.
+BUFFER-OR-STRING defaults to the current buffer if omitted.
+This operation does not insert any characters,
+but otherwise acts as if there were a replicating extent whose
+parent is EXTENT in some string that was just inserted.
+Returns the newly-inserted extent.
+The fourth arg, NO-HOOKS, can be used to inhibit the running of the
+extent's `paste-function' property if it has one.
+See documentation on `detach-extent' for a discussion of undo recording.
+*/
+(extent, start, end, no_hooks, buffer_or_string))
+{
+EXTENT ext = decode_extent (extent, 0);
+Lisp_Object copy;
+Bytind s, e;
+buffer_or_string = decode_buffer_or_string (buffer_or_string);
+get_buffer_or_string_range_byte (buffer_or_string, start, end, &s, &e,
+				   GB_ALLOW_PAST_ACCESSIBLE);
+copy = insert_extent (ext, s, e, buffer_or_string, NILP (no_hooks));
+if (EXTENTP (copy))
+{
+if (extent_duplicable_p (XEXTENT (copy)))
+	record_extent (copy, 1);
+}
+return copy;
+}
+/* adding buffer extents to a string */
+struct add_string_extents_arg
+{
+Bytind from;
+Bytecount length;
+Lisp_Object string;
+};
+static int
+add_string_extents_mapper (EXTENT extent, void *arg)
+{
+/* This function can GC */
+struct add_string_extents_arg *closure =
+(struct add_string_extents_arg *) arg;
+Bytecount start = extent_endpoint_bytind (extent, 0) - closure->from;
+Bytecount end   = extent_endpoint_bytind (extent, 1) - closure->from;
+if (extent_duplicable_p (extent))
+{
+start = max (start, 0);
+end = min (end, closure->length);
+/* Run the copy-function to give an extent the option of
+	 not being copied into the string (or kill ring).
+	 */
+if (extent_duplicable_p (extent) &&
+	  !run_extent_copy_function (extent, start + closure->from,
+				     end + closure->from))
+	return 0;
+copy_extent (extent, start, end, closure->string);
+}
+return 0;
+}
+/* Add the extents in buffer BUF from OPOINT to OPOINT+LENGTH to
+the string STRING. */
+void
+add_string_extents (Lisp_Object string, struct buffer *buf, Bytind opoint,
+		    Bytecount length)
+{
+/* This function can GC */
+struct add_string_extents_arg closure;
+struct gcpro gcpro1, gcpro2;
+Lisp_Object buffer;
+closure.from = opoint;
+closure.length = length;
+closure.string = string;
+buffer = make_buffer (buf);
+GCPRO2 (buffer, string);
+map_extents_bytind (opoint, opoint + length, add_string_extents_mapper,
+		      (void *) &closure, buffer, 0,
+		      /* ignore extents that just abut the region */
+		      ME_END_CLOSED | ME_ALL_EXTENTS_OPEN |
+		      /* we are calling E-Lisp (the extent's copy function)
+			 so anything might happen */
+		      ME_MIGHT_CALL_ELISP);
+UNGCPRO;
+}
+struct splice_in_string_extents_arg
+{
+Bytecount pos;
+Bytecount length;
+Bytind opoint;
+Lisp_Object buffer;
+};
+static int
+splice_in_string_extents_mapper (EXTENT extent, void *arg)
+{
+/* This function can GC */
+struct splice_in_string_extents_arg *closure =
+(struct splice_in_string_extents_arg *) arg;
+/* BASE_START and BASE_END are the limits in the buffer of the string
+that was just inserted.
+NEW_START and NEW_END are the prospective buffer positions of the
+extent that is going into the buffer. */
+Bytind base_start = closure->opoint;
+Bytind base_end = base_start + closure->length;
+Bytind new_start = (base_start + extent_endpoint_bytind (extent, 0) -
+		      closure->pos);
+Bytind new_end = (base_start + extent_endpoint_bytind (extent, 1) -
+		    closure->pos);
+if (new_start < base_start)
+new_start = base_start;
+if (new_end > base_end)
+new_end = base_end;
+if (new_end <= new_start)
+return 0;
+if (!extent_duplicable_p (extent))
+return 0;
+if (!inside_undo &&
+!run_extent_paste_function (extent, new_start, new_end,
+				  closure->buffer))
+return 0;
+copy_extent (extent, new_start, new_end, closure->buffer);
+return 0;
+}
+/* We have just inserted a section of STRING (starting at POS, of
+length LENGTH) into buffer BUF at OPOINT.  Do whatever is necessary
+to get the string's extents into the buffer. */
+void
+splice_in_string_extents (Lisp_Object string, struct buffer *buf,
+			  Bytind opoint, Bytecount length, Bytecount pos)
+{
+struct splice_in_string_extents_arg closure;
+struct gcpro gcpro1, gcpro2;
+Lisp_Object buffer;
+buffer = make_buffer (buf);
+closure.opoint = opoint;
+closure.pos = pos;
+closure.length = length;
+closure.buffer = buffer;
+GCPRO2 (buffer, string);
+map_extents_bytind (pos, pos + length,
+		      splice_in_string_extents_mapper,
+		      (void *) &closure, string, 0,
+		      /* ignore extents that just abut the region */
+		      ME_END_CLOSED | ME_ALL_EXTENTS_OPEN |
+		      /* we are calling E-Lisp (the extent's copy function)
+			 so anything might happen */
+		      ME_MIGHT_CALL_ELISP);
+UNGCPRO;
+}
+struct copy_string_extents_arg
+{
+Bytecount new_pos;
+Bytecount old_pos;
+Bytecount length;
+Lisp_Object new_string;
+};
+struct copy_string_extents_1_arg
+{
+Lisp_Object parent_in_question;
+EXTENT found_extent;
+};
+static int
+copy_string_extents_mapper (EXTENT extent, void *arg)
+{
+struct copy_string_extents_arg *closure =
+(struct copy_string_extents_arg *) arg;
+Bytecount old_start, old_end, new_start, new_end;
+old_start = extent_endpoint_bytind (extent, 0);
+old_end   = extent_endpoint_bytind (extent, 1);
+old_start = max (closure->old_pos, old_start);
+old_end   = min (closure->old_pos + closure->length, old_end);
+if (old_start >= old_end)
+return 0;
+new_start = old_start + closure->new_pos - closure->old_pos;
+new_end   = old_end   + closure->new_pos - closure->old_pos;
+copy_extent (extent, new_start, new_end, closure->new_string);
+return 0;
+}
+/* The string NEW_STRING was partially constructed from OLD_STRING.
+In particular, the section of length LEN starting at NEW_POS in
+NEW_STRING came from the section of the same length starting at
+OLD_POS in OLD_STRING.  Copy the extents as appropriate. */
+void
+copy_string_extents (Lisp_Object new_string, Lisp_Object old_string,
+		     Bytecount new_pos, Bytecount old_pos,
+		     Bytecount length)
+{
+struct copy_string_extents_arg closure;
+struct gcpro gcpro1, gcpro2;
+closure.new_pos = new_pos;
+closure.old_pos = old_pos;
+closure.new_string = new_string;
+closure.length = length;
+GCPRO2 (new_string, old_string);
+map_extents_bytind (old_pos, old_pos + length,
+		      copy_string_extents_mapper,
+		      (void *) &closure, old_string, 0,
+		      /* ignore extents that just abut the region */
+		      ME_END_CLOSED | ME_ALL_EXTENTS_OPEN |
+		      /* we are calling E-Lisp (the extent's copy function)
+			 so anything might happen */
+		      ME_MIGHT_CALL_ELISP);
+UNGCPRO;
+}
+/* Checklist for sanity checking:
+- {kill, yank, copy} at {open, closed} {start, end} of {writable, read-only} extent
+- {kill, copy} & yank {once, repeatedly} duplicable extent in {same, different} buffer
+*/
+/************************************************************************/
+/*				text properties				*/
+/************************************************************************/
+/* Text properties
+Originally this stuff was implemented in lisp (all of the functionality
+exists to make that possible) but speed was a problem.
+*/
+Lisp_Object Qtext_prop;
+Lisp_Object Qtext_prop_extent_paste_function;
+static Lisp_Object
+get_text_property_bytind (Bytind position, Lisp_Object prop,
+			  Lisp_Object object, enum extent_at_flag fl,
+			  int text_props_only)
+{
+Lisp_Object extent;
+/* text_props_only specifies whether we only consider text-property
+extents (those with the 'text-prop property set) or all extents. */
+if (!text_props_only)
+extent = extent_at_bytind (position, object, prop, 0, fl);
+else
+{
+EXTENT prior = 0;
+while (1)
+	{
+	  extent = extent_at_bytind (position, object, Qtext_prop, prior,
+				     fl);
+	  if (NILP (extent))
+	    return Qnil;
+	  if (EQ (prop, Fextent_property (extent, Qtext_prop, Qnil)))
+	    break;
+	  prior = XEXTENT (extent);
+	}
+}
+if (!NILP (extent))
+return Fextent_property (extent, prop, Qnil);
+if (!NILP (Vdefault_text_properties))
+return Fplist_get (Vdefault_text_properties, prop, Qnil);
+return Qnil;
+}
+static Lisp_Object
+get_text_property_1 (Lisp_Object pos, Lisp_Object prop, Lisp_Object object,
+		     Lisp_Object at_flag, int text_props_only)
+{
+Bytind position;
+int invert = 0;
+object = decode_buffer_or_string (object);
+position = get_buffer_or_string_pos_byte (object, pos, GB_NO_ERROR_IF_BAD);
+/* We canonicalize the start/end-open/closed properties to the
+non-default version -- "adding" the default property really
+needs to remove the non-default one.  See below for more
+on this. */
+if (EQ (prop, Qstart_closed))
+{
+prop = Qstart_open;
+invert = 1;
+}
+if (EQ (prop, Qend_open))
+{
+prop = Qend_closed;
+invert = 1;
+}
+{
+Lisp_Object val =
+get_text_property_bytind (position, prop, object,
+				decode_extent_at_flag (at_flag),
+				text_props_only);
+if (invert)
+val = NILP (val) ? Qt : Qnil;
+return val;
+}
+}
+DEFUN ("get-text-property", Fget_text_property, 2, 4, 0, /*
+Return the value of the PROP property at the given position.
+Optional arg OBJECT specifies the buffer or string to look in, and
+defaults to the current buffer.
+Optional arg AT-FLAG controls what it means for a property to be "at"
+a position, and has the same meaning as in `extent-at'.
+This examines only those properties added with `put-text-property'.
+See also `get-char-property'.
+*/
+(pos, prop, object, at_flag))
+{
+return get_text_property_1 (pos, prop, object, at_flag, 1);
+}
+DEFUN ("get-char-property", Fget_char_property, 2, 4, 0, /*
+Return the value of the PROP property at the given position.
+Optional arg OBJECT specifies the buffer or string to look in, and
+defaults to the current buffer.
+Optional arg AT-FLAG controls what it means for a property to be "at"
+a position, and has the same meaning as in `extent-at'.
+This examines properties on all extents.
+See also `get-text-property'.
+*/
+(pos, prop, object, at_flag))
+{
+return get_text_property_1 (pos, prop, object, at_flag, 0);
+}
+/* About start/end-open/closed:
+These properties have to be handled specially because of their
+strange behavior.  If I put the "start-open" property on a region,
+then *all* text-property extents in the region have to have their
+start be open.  This is unlike all other properties, which don't
+affect the extents of text properties other than their own.
+So:
+1) We have to map start-closed to (not start-open) and end-open
+to (not end-closed) -- i.e. adding the default is really the
+same as remove the non-default property.  It won't work, for
+example, to have both "start-open" and "start-closed" on
+the same region.
+2) Whenever we add one of these properties, we go through all
+text-property extents in the region and set the appropriate
+open/closedness on them.
+3) Whenever we change a text-property extent for a property,
+we have to make sure we set the open/closedness properly.
+(2) and (3) together rely on, and maintain, the invariant
+that the open/closedness of text-property extents is correct
+at the beginning and end of each operation.
+*/
+struct put_text_prop_arg
+{
+Lisp_Object prop, value;	/* The property and value we are storing */
+Bytind start, end;	/* The region into which we are storing it */
+Lisp_Object object;
+Lisp_Object the_extent;	/* Our chosen extent; this is used for
+				   communication between subsequent passes. */
+int changed_p;		/* Output: whether we have modified anything */
+};
+static int
+put_text_prop_mapper (EXTENT e, void *arg)
+{
+struct put_text_prop_arg *closure = (struct put_text_prop_arg *) arg;
+Lisp_Object object = closure->object;
+Lisp_Object value = closure->value;
+Bytind e_start, e_end;
+Bytind start = closure->start;
+Bytind end   = closure->end;
+Lisp_Object extent, e_val;
+int is_eq;
+XSETEXTENT (extent, e);
+/* Note: in some cases when the property itself is 'start-open
+or 'end-closed, the checks to set the openness may do a bit
+of extra work; but it won't hurt because we then fix up the
+openness later on in put_text_prop_openness_mapper(). */
+if (!EQ (Fextent_property (extent, Qtext_prop, Qnil), closure->prop))
+/* It's not for this property; do nothing. */
+return 0;
+e_start = extent_endpoint_bytind (e, 0);
+e_end   = extent_endpoint_bytind (e, 1);
+e_val = Fextent_property (extent, closure->prop, Qnil);
+is_eq = EQ (value, e_val);
+if (!NILP (value) && NILP (closure->the_extent) && is_eq)
+{
+/* We want there to be an extent here at the end, and we haven't picked
+	 one yet, so use this one.  Extend it as necessary.  We only reuse an
+	 extent which has an EQ value for the prop in question to avoid
+	 side-effecting the kill ring (that is, we never change the property
+	 on an extent after it has been created.)
+*/
+if (e_start != start || e_end != end)
+	{
+	  Bytind new_start = min (e_start, start);
+	  Bytind new_end = max (e_end, end);
+	  set_extent_endpoints (e, new_start, new_end, Qnil);
+	  /* If we changed the endpoint, then we need to set its
+	     openness. */
+	  set_extent_openness (e, new_start != e_start
+			       ? !NILP (get_text_property_bytind
+					(start, Qstart_open, object,
+					 EXTENT_AT_AFTER, 1)) : -1,
+			       new_end != e_end
+			       ? NILP (get_text_property_bytind
+				       (end - 1, Qend_closed, object,
+					EXTENT_AT_AFTER, 1))
+			       : -1);
+	  closure->changed_p = 1;
+	}
+closure->the_extent = extent;
+}
+/* Even if we're adding a prop, at this point, we want all other extents of
+this prop to go away (as now they overlap).  So the theory here is that,
+when we are adding a prop to a region that has multiple (disjoint)
+occurrences of that prop in it already, we pick one of those and extend
+it, and remove the others.
+*/
+else if (EQ (extent, closure->the_extent))
+{
+/* just in case map-extents hits it again (does that happen?) */
+;
+}
+else if (e_start >= start && e_end <= end)
+{
+/* Extent is contained in region; remove it.  Don't destroy or modify
+	 it, because we don't want to change the attributes pointed to by the
+	 duplicates in the kill ring.
+*/
+extent_detach (e);
+closure->changed_p = 1;
+}
+else if (!NILP (closure->the_extent) &&
+	   is_eq &&
+	   e_start <= end &&
+	   e_end >= start)
+{
+EXTENT te = XEXTENT (closure->the_extent);
+/* This extent overlaps, and has the same prop/value as the extent we've
+	 decided to reuse, so we can remove this existing extent as well (the
+	 whole thing, even the part outside of the region) and extend
+	 the-extent to cover it, resulting in the minimum number of extents in
+	 the buffer.
+*/
+Bytind the_start = extent_endpoint_bytind (te, 0);
+Bytind the_end = extent_endpoint_bytind (te, 1);
+if (e_start != the_start &&  /* note AND not OR -- hmm, why is this
+				      the case? I think it's because the
+				      assumption that the text-property
+				      extents don't overlap makes it
+				      OK; changing it to an OR would
+				      result in changed_p sometimes getting
+				      falsely marked.  Is this bad? */
+	  e_end   != the_end)
+	{
+	  Bytind new_start = min (e_start, the_start);
+	  Bytind new_end = max (e_end, the_end);
+	  set_extent_endpoints (te, new_start, new_end, Qnil);
+	  /* If we changed the endpoint, then we need to set its
+	     openness.  We are setting the endpoint to be the same as
+	     that of the extent we're about to remove, and we assume
+	     (the invariant mentioned above) that extent has the
+	     proper endpoint setting, so we just use it. */
+	  set_extent_openness (te, new_start != e_start ?
+			       (int) extent_start_open_p (e) : -1,
+			       new_end != e_end ?
+			       (int) extent_end_open_p (e) : -1);
+	  closure->changed_p = 1;
+	}
+extent_detach (e);
+}
+else if (e_end <= end)
+{
+/* Extent begins before start but ends before end, so we can just
+	 decrease its end position.
+*/
+if (e_end != start)
+	{
+	  set_extent_endpoints (e, e_start, start, Qnil);
+	  set_extent_openness (e, -1, NILP (get_text_property_bytind
+				       (start - 1, Qend_closed, object,
+					EXTENT_AT_AFTER, 1)));
+	  closure->changed_p = 1;
+	}
+}
+else if (e_start >= start)
+{
+/* Extent ends after end but begins after start, so we can just
+	 increase its start position.
+*/
+if (e_start != end)
+	{
+	  set_extent_endpoints (e, end, e_end, Qnil);
+	  set_extent_openness (e, !NILP (get_text_property_bytind
+					(end, Qstart_open, object,
+					 EXTENT_AT_AFTER, 1)), -1);
+	  closure->changed_p = 1;
+	}
+}
+else
+{
+/* Otherwise, `extent' straddles the region.  We need to split it.
+*/
+set_extent_endpoints (e, e_start, start, Qnil);
+set_extent_openness (e, -1, NILP (get_text_property_bytind
+					(start - 1, Qend_closed, object,
+					 EXTENT_AT_AFTER, 1)));
+set_extent_openness (copy_extent (e, end, e_end, extent_object (e)),
+			   !NILP (get_text_property_bytind
+				  (end, Qstart_open, object,
+				   EXTENT_AT_AFTER, 1)), -1);
+closure->changed_p = 1;
+}
+return 0;  /* to continue mapping. */
+}
+static int
+put_text_prop_openness_mapper (EXTENT e, void *arg)
+{
+struct put_text_prop_arg *closure = (struct put_text_prop_arg *) arg;
+Bytind e_start, e_end;
+Bytind start = closure->start;
+Bytind end   = closure->end;
+Lisp_Object extent;
+XSETEXTENT (extent, e);
+e_start = extent_endpoint_bytind (e, 0);
+e_end   = extent_endpoint_bytind (e, 1);
+if (NILP (Fextent_property (extent, Qtext_prop, Qnil)))
+{
+/* It's not a text-property extent; do nothing. */
+;
+}
+/* Note end conditions and NILP/!NILP's carefully. */
+else if (EQ (closure->prop, Qstart_open)
+	   && e_start >= start && e_start < end)
+set_extent_openness (e, !NILP (closure->value), -1);
+else if (EQ (closure->prop, Qend_closed)
+	   && e_end > start && e_end <= end)
+set_extent_openness (e, -1, NILP (closure->value));
+return 0;  /* to continue mapping. */
+}
+static int
+put_text_prop (Bytind start, Bytind end, Lisp_Object object,
+	       Lisp_Object prop, Lisp_Object value,
+	       int duplicable_p)
+{
+/* This function can GC */
+struct put_text_prop_arg closure;
+if (start == end)   /* There are no characters in the region. */
+return 0;
+/* convert to the non-default versions, since a nil property is
+the same as it not being present. */
+if (EQ (prop, Qstart_closed))
+{
+prop = Qstart_open;
+value = NILP (value) ? Qt : Qnil;
+}
+else if (EQ (prop, Qend_open))
+{
+prop = Qend_closed;
+value = NILP (value) ? Qt : Qnil;
+}
+value = canonicalize_extent_property (prop, value);
+closure.prop = prop;
+closure.value = value;
+closure.start = start;
+closure.end = end;
+closure.object = object;
+closure.changed_p = 0;
+closure.the_extent = Qnil;
+map_extents_bytind (start, end,
+		      put_text_prop_mapper,
+		      (void *) &closure, object, 0,
+		      /* get all extents that abut the region */
+		      ME_ALL_EXTENTS_CLOSED | ME_END_CLOSED |
+		      /* it might QUIT or error if the user has
+			 fucked with the extent plist. */
+		      /* #### dmoore - I think this should include
+			 ME_MIGHT_MOVE_SOE, since the callback function
+			 might recurse back into map_extents_bytind. */
+		      ME_MIGHT_THROW |
+		      ME_MIGHT_MODIFY_EXTENTS);
+/* If we made it through the loop without reusing an extent
+(and we want there to be one) make it now.
+*/
+if (!NILP (value) && NILP (closure.the_extent))
+{
+Lisp_Object extent;
+XSETEXTENT (extent, make_extent_internal (object, start, end));
+closure.changed_p = 1;
+Fset_extent_property (extent, Qtext_prop, prop);
+Fset_extent_property (extent, prop, value);
+if (duplicable_p)
+	{
+	  extent_duplicable_p (XEXTENT (extent)) = 1;
+	  Fset_extent_property (extent, Qpaste_function,
+				Qtext_prop_extent_paste_function);
+	}
+set_extent_openness (XEXTENT (extent),
+			   !NILP (get_text_property_bytind
+				  (start, Qstart_open, object,
+				   EXTENT_AT_AFTER, 1)),
+			   NILP (get_text_property_bytind
+				 (end - 1, Qend_closed, object,
+				  EXTENT_AT_AFTER, 1)));
+}
+if (EQ (prop, Qstart_open) || EQ (prop, Qend_closed))
+{
+map_extents_bytind (start, end,
+			  put_text_prop_openness_mapper,
+			  (void *) &closure, object, 0,
+			  /* get all extents that abut the region */
+			  ME_ALL_EXTENTS_CLOSED | ME_END_CLOSED |
+			  ME_MIGHT_MODIFY_EXTENTS);
+}
+return closure.changed_p;
+}
+DEFUN ("put-text-property", Fput_text_property, 4, 5, 0, /*
+Adds the given property/value to all characters in the specified region.
+The property is conceptually attached to the characters rather than the
+region.  The properties are copied when the characters are copied/pasted.
+Fifth argument OBJECT is the buffer or string containing the text, and
+defaults to the current buffer.
+*/
+(start, end, prop, value, object))
+{
+/* This function can GC */
+Bytind s, e;
+object = decode_buffer_or_string (object);
+get_buffer_or_string_range_byte (object, start, end, &s, &e, 0);
+put_text_prop (s, e, object, prop, value, 1);
+return prop;
+}
+DEFUN ("put-nonduplicable-text-property", Fput_nonduplicable_text_property,
+4, 5, 0, /*
+Adds the given property/value to all characters in the specified region.
+The property is conceptually attached to the characters rather than the
+region, however the properties will not be copied when the characters
+are copied.
+Fifth argument OBJECT is the buffer or string containing the text, and
+defaults to the current buffer.
+*/
+(start, end, prop, value, object))
+{
+/* This function can GC */
+Bytind s, e;
+object = decode_buffer_or_string (object);
+get_buffer_or_string_range_byte (object, start, end, &s, &e, 0);
+put_text_prop (s, e, object, prop, value, 0);
+return prop;
+}
+DEFUN ("add-text-properties", Fadd_text_properties, 3, 4, 0, /*
+Add properties to the characters from START to END.
+The third argument PROPS is a property list specifying the property values
+to add.  The optional fourth argument, OBJECT, is the buffer or string
+containing the text and defaults to the current buffer.  Returns t if
+any property was changed, nil otherwise.
+*/
+(start, end, props, object))
+{
+/* This function can GC */
+int changed = 0;
+Bytind s, e;
+object = decode_buffer_or_string (object);
+get_buffer_or_string_range_byte (object, start, end, &s, &e, 0);
+CHECK_LIST (props);
+for (; !NILP (props); props = Fcdr (Fcdr (props)))
+{
+Lisp_Object prop = XCAR (props);
+Lisp_Object value = Fcar (XCDR (props));
+changed |= put_text_prop (s, e, object, prop, value, 1);
+}
+return changed ? Qt : Qnil;
+}
+DEFUN ("add-nonduplicable-text-properties", Fadd_nonduplicable_text_properties,
+3, 4, 0, /*
+Add nonduplicable properties to the characters from START to END.
+\(The properties will not be copied when the characters are copied.)
+The third argument PROPS is a property list specifying the property values
+to add.  The optional fourth argument, OBJECT, is the buffer or string
+containing the text and defaults to the current buffer.  Returns t if
+any property was changed, nil otherwise.
+*/
+(start, end, props, object))
+{
+/* This function can GC */
+int changed = 0;
+Bytind s, e;
+object = decode_buffer_or_string (object);
+get_buffer_or_string_range_byte (object, start, end, &s, &e, 0);
+CHECK_LIST (props);
+for (; !NILP (props); props = Fcdr (Fcdr (props)))
+{
+Lisp_Object prop = XCAR (props);
+Lisp_Object value = Fcar (XCDR (props));
+changed |= put_text_prop (s, e, object, prop, value, 0);
+}
+return changed ? Qt : Qnil;
+}
+DEFUN ("remove-text-properties", Fremove_text_properties, 3, 4, 0, /*
+Remove the given properties from all characters in the specified region.
+PROPS should be a plist, but the values in that plist are ignored (treated
+as nil).  Returns t if any property was changed, nil otherwise.
+Fourth argument OBJECT is the buffer or string containing the text, and
+defaults to the current buffer.
+*/
+(start, end, props, object))
+{
+/* This function can GC */
+int changed = 0;
+Bytind s, e;
+object = decode_buffer_or_string (object);
+get_buffer_or_string_range_byte (object, start, end, &s, &e, 0);
+CHECK_LIST (props);
+for (; !NILP (props); props = Fcdr (Fcdr (props)))
+{
+Lisp_Object prop = XCAR (props);
+changed |= put_text_prop (s, e, object, prop, Qnil, 1);
+}
+return changed ? Qt : Qnil;
+}
+/* Whenever a text-prop extent is pasted into a buffer (via `yank' or `insert'
+or whatever) we attach the properties to the buffer by calling
+`put-text-property' instead of by simply allowing the extent to be copied or
+re-attached.  Then we return nil, telling the extents code not to attach it
+again.  By handing the insertion hackery in this way, we make kill/yank
+behave consistently with put-text-property and not fragment the extents
+(since text-prop extents must partition, not overlap).
+The lisp implementation of this was probably fast enough, but since I moved
+the rest of the put-text-prop code here, I moved this as well for
+completeness.
+*/
+DEFUN ("text-prop-extent-paste-function", Ftext_prop_extent_paste_function,
+3, 3, 0, /*
+Used as the `paste-function' property of `text-prop' extents.
+*/
+(extent, from, to))
+{
+/* This function can GC */
+Lisp_Object prop, val;
+prop = Fextent_property (extent, Qtext_prop, Qnil);
+if (NILP (prop))
+signal_simple_error ("Internal error: no text-prop", extent);
+val = Fextent_property (extent, prop, Qnil);
+#if 0
+/* removed by bill perry, 2/9/97
+** This little bit of code would not allow you to have a text property
+** with a value of Qnil.  This is bad bad bad.
+*/
+if (NILP (val))
+signal_simple_error_2 ("Internal error: no text-prop",
+			   extent, prop);
+#endif
+Fput_text_property (from, to, prop, val, Qnil);
+return Qnil; /* important! */
+}
+/* This function could easily be written in Lisp but the C code wants
+to use it in connection with invisible extents (at least currently).
+If this changes, consider moving this back into Lisp. */
+DEFUN ("next-single-property-change", Fnext_single_property_change,
+2, 4, 0, /*
+Return the position of next property change for a specific property.
+Scans characters forward from POS till it finds a change in the PROP
+property, then returns the position of the change.  The optional third
+argument OBJECT is the buffer or string to scan (defaults to the current
+buffer).
+The property values are compared with `eq'.
+Return nil if the property is constant all the way to the end of BUFFER.
+If the value is non-nil, it is a position greater than POS, never equal.
+If the optional fourth argument LIMIT is non-nil, don't search
+past position LIMIT; return LIMIT if nothing is found before LIMIT.
+If two or more extents with conflicting non-nil values for PROP overlap
+a particular character, it is undefined which value is considered to be
+the value of PROP. (Note that this situation will not happen if you always
+use the text-property primitives.)
+*/
+(pos, prop, object, limit))
+{
+Bufpos bpos;
+Bufpos blim;
+Lisp_Object extent, value;
+int limit_was_nil;
+object = decode_buffer_or_string (object);
+bpos = get_buffer_or_string_pos_char (object, pos, 0);
+if (NILP (limit))
+{
+blim = buffer_or_string_accessible_end_char (object);
+limit_was_nil = 1;
+}
+else
+{
+blim = get_buffer_or_string_pos_char (object, limit, 0);
+limit_was_nil = 0;
+}
+extent = Fextent_at (make_int (bpos), object, prop, Qnil, Qnil);
+if (!NILP (extent))
+value = Fextent_property (extent, prop, Qnil);
+else
+value = Qnil;
+while (1)
+{
+bpos = XINT (Fnext_extent_change (make_int (bpos), object));
+if (bpos >= blim)
+	break; /* property is the same all the way to the end */
+extent = Fextent_at (make_int (bpos), object, prop, Qnil, Qnil);
+if ((NILP (extent) && !NILP (value)) ||
+	  (!NILP (extent) && !EQ (value,
+				  Fextent_property (extent, prop, Qnil))))
+	return make_int (bpos);
+}
+/* I think it's more sensible for this function to return nil always
+in this situation and it used to do it this way, but it's been changed
+for FSF compatibility. */
+if (limit_was_nil)
+return Qnil;
+else
+return make_int (blim);
+}
+/* See comment on previous function about why this is written in C. */
+DEFUN ("previous-single-property-change", Fprevious_single_property_change,
+2, 4, 0, /*
+Return the position of next property change for a specific property.
+Scans characters backward from POS till it finds a change in the PROP
+property, then returns the position of the change.  The optional third
+argument OBJECT is the buffer or string to scan (defaults to the current
+buffer).
+The property values are compared with `eq'.
+Return nil if the property is constant all the way to the start of BUFFER.
+If the value is non-nil, it is a position less than POS, never equal.
+If the optional fourth argument LIMIT is non-nil, don't search back
+past position LIMIT; return LIMIT if nothing is found until LIMIT.
+If two or more extents with conflicting non-nil values for PROP overlap
+a particular character, it is undefined which value is considered to be
+the value of PROP. (Note that this situation will not happen if you always
+use the text-property primitives.)
+*/
+(pos, prop, object, limit))
+{
+Bufpos bpos;
+Bufpos blim;
+Lisp_Object extent, value;
+int limit_was_nil;
+object = decode_buffer_or_string (object);
+bpos = get_buffer_or_string_pos_char (object, pos, 0);
+if (NILP (limit))
+{
+blim = buffer_or_string_accessible_begin_char (object);
+limit_was_nil = 1;
+}
+else
+{
+blim = get_buffer_or_string_pos_char (object, limit, 0);
+limit_was_nil = 0;
+}
+/* extent-at refers to the character AFTER bpos, but we want the
+character before bpos.  Thus the - 1.  extent-at simply
+returns nil on bogus positions, so not to worry. */
+extent = Fextent_at (make_int (bpos - 1), object, prop, Qnil, Qnil);
+if (!NILP (extent))
+value = Fextent_property (extent, prop, Qnil);
+else
+value = Qnil;
+while (1)
+{
+bpos = XINT (Fprevious_extent_change (make_int (bpos), object));
+if (bpos <= blim)
+	break; /* property is the same all the way to the beginning */
+extent = Fextent_at (make_int (bpos - 1), object, prop, Qnil, Qnil);
+if ((NILP (extent) && !NILP (value)) ||
+	  (!NILP (extent) && !EQ (value,
+				  Fextent_property (extent, prop, Qnil))))
+	return make_int (bpos);
+}
+/* I think it's more sensible for this function to return nil always
+in this situation and it used to do it this way, but it's been changed
+for FSF compatibility. */
+if (limit_was_nil)
+return Qnil;
+else
+return make_int (blim);
+}
+#ifdef MEMORY_USAGE_STATS
+int
+compute_buffer_extent_usage (struct buffer *b, struct overhead_stats *ovstats)
+{
+/* #### not yet written */
+return 0;
+}
+#endif /* MEMORY_USAGE_STATS */
+/************************************************************************/
+/*				initialization				*/
+/************************************************************************/
+void
+syms_of_extents (void)
+{
+defsymbol (&Qextentp, "extentp");
+defsymbol (&Qextent_live_p, "extent-live-p");
+defsymbol (&Qall_extents_closed, "all-extents-closed");
+defsymbol (&Qall_extents_open, "all-extents-open");
+defsymbol (&Qall_extents_closed_open, "all-extents-closed-open");
+defsymbol (&Qall_extents_open_closed, "all-extents-open-closed");
+defsymbol (&Qstart_in_region, "start-in-region");
+defsymbol (&Qend_in_region, "end-in-region");
+defsymbol (&Qstart_and_end_in_region, "start-and-end-in-region");
+defsymbol (&Qstart_or_end_in_region, "start-or-end-in-region");
+defsymbol (&Qnegate_in_region, "negate-in-region");
+defsymbol (&Qdetached, "detached");
+defsymbol (&Qdestroyed, "destroyed");
+defsymbol (&Qbegin_glyph, "begin-glyph");
+defsymbol (&Qend_glyph, "end-glyph");
+defsymbol (&Qstart_open, "start-open");
+defsymbol (&Qend_open, "end-open");
+defsymbol (&Qstart_closed, "start-closed");
+defsymbol (&Qend_closed, "end-closed");
+defsymbol (&Qread_only, "read-only");
+/* defsymbol (&Qhighlight, "highlight"); in faces.c */
+defsymbol (&Qunique, "unique");
+defsymbol (&Qduplicable, "duplicable");
+defsymbol (&Qdetachable, "detachable");
+defsymbol (&Qpriority, "priority");
+defsymbol (&Qmouse_face, "mouse-face");
+defsymbol (&Qinitial_redisplay_function,"initial-redisplay-function");
+defsymbol (&Qglyph_layout, "glyph-layout");	/* backwards compatibility */
+defsymbol (&Qbegin_glyph_layout, "begin-glyph-layout");
+defsymbol (&Qend_glyph_layout, "end-glyph-layout");
+defsymbol (&Qoutside_margin, "outside-margin");
+defsymbol (&Qinside_margin, "inside-margin");
+defsymbol (&Qwhitespace, "whitespace");
+/* Qtext defined in general.c */
+defsymbol (&Qpaste_function, "paste-function");
+defsymbol (&Qcopy_function,  "copy-function");
+defsymbol (&Qtext_prop, "text-prop");
+defsymbol (&Qtext_prop_extent_paste_function,
+	     "text-prop-extent-paste-function");
+DEFSUBR (Fextentp);
+DEFSUBR (Fextent_live_p);
+DEFSUBR (Fextent_detached_p);
+DEFSUBR (Fextent_start_position);
+DEFSUBR (Fextent_end_position);
+DEFSUBR (Fextent_object);
+DEFSUBR (Fextent_length);
+DEFSUBR (Fmake_extent);
+DEFSUBR (Fcopy_extent);
+DEFSUBR (Fdelete_extent);
+DEFSUBR (Fdetach_extent);
+DEFSUBR (Fset_extent_endpoints);
+DEFSUBR (Fnext_extent);
+DEFSUBR (Fprevious_extent);
+#if DEBUG_XEMACS
+DEFSUBR (Fnext_e_extent);
+DEFSUBR (Fprevious_e_extent);
+#endif
+DEFSUBR (Fnext_extent_change);
+DEFSUBR (Fprevious_extent_change);
+DEFSUBR (Fextent_parent);
+DEFSUBR (Fextent_children);
+DEFSUBR (Fset_extent_parent);
+DEFSUBR (Fextent_in_region_p);
+DEFSUBR (Fmap_extents);
+DEFSUBR (Fmap_extent_children);
+DEFSUBR (Fextent_at);
+DEFSUBR (Fset_extent_initial_redisplay_function);
+DEFSUBR (Fextent_face);
+DEFSUBR (Fset_extent_face);
+DEFSUBR (Fextent_mouse_face);
+DEFSUBR (Fset_extent_mouse_face);
+DEFSUBR (Fset_extent_begin_glyph);
+DEFSUBR (Fset_extent_end_glyph);
+DEFSUBR (Fextent_begin_glyph);
+DEFSUBR (Fextent_end_glyph);
+DEFSUBR (Fset_extent_begin_glyph_layout);
+DEFSUBR (Fset_extent_end_glyph_layout);
+DEFSUBR (Fextent_begin_glyph_layout);
+DEFSUBR (Fextent_end_glyph_layout);
+DEFSUBR (Fset_extent_priority);
+DEFSUBR (Fextent_priority);
+DEFSUBR (Fset_extent_property);
+DEFSUBR (Fset_extent_properties);
+DEFSUBR (Fextent_property);
+DEFSUBR (Fextent_properties);
+DEFSUBR (Fhighlight_extent);
+DEFSUBR (Fforce_highlight_extent);
+DEFSUBR (Finsert_extent);
+DEFSUBR (Fget_text_property);
+DEFSUBR (Fget_char_property);
+DEFSUBR (Fput_text_property);
+DEFSUBR (Fput_nonduplicable_text_property);
+DEFSUBR (Fadd_text_properties);
+DEFSUBR (Fadd_nonduplicable_text_properties);
+DEFSUBR (Fremove_text_properties);
+DEFSUBR (Ftext_prop_extent_paste_function);
+DEFSUBR (Fnext_single_property_change);
+DEFSUBR (Fprevious_single_property_change);
+}
+void
+reinit_vars_of_extents (void)
+{
+extent_auxiliary_defaults.begin_glyph = Qnil;
+extent_auxiliary_defaults.end_glyph = Qnil;
+extent_auxiliary_defaults.parent = Qnil;
+extent_auxiliary_defaults.children = Qnil;
+extent_auxiliary_defaults.priority = 0;
+extent_auxiliary_defaults.invisible = Qnil;
+extent_auxiliary_defaults.read_only = Qnil;
+extent_auxiliary_defaults.mouse_face = Qnil;
+extent_auxiliary_defaults.initial_redisplay_function = Qnil;
+extent_auxiliary_defaults.before_change_functions = Qnil;
+extent_auxiliary_defaults.after_change_functions = Qnil;
+}
+void
+vars_of_extents (void)
+{
+reinit_vars_of_extents ();
+DEFVAR_INT ("mouse-highlight-priority", &mouse_highlight_priority /*
+The priority to use for the mouse-highlighting pseudo-extent
+that is used to highlight extents with the `mouse-face' attribute set.
+See `set-extent-priority'.
+*/ );
+/* Set mouse-highlight-priority (which ends up being used both for the
+mouse-highlighting pseudo-extent and the primary selection extent)
+to a very high value because very few extents should override it.
+1000 gives lots of room below it for different-prioritized extents.
+10 doesn't. ediff, for example, likes to use priorities around 100.
+--ben */
+mouse_highlight_priority = /* 10 */ 1000;
+DEFVAR_LISP ("default-text-properties", &Vdefault_text_properties /*
+Property list giving default values for text properties.
+Whenever a character does not specify a value for a property, the value
+stored in this list is used instead.  This only applies when the
+functions `get-text-property' or `get-char-property' are called.
+*/ );
+Vdefault_text_properties = Qnil;
+staticpro (&Vlast_highlighted_extent);
+Vlast_highlighted_extent = Qnil;
+Vextent_face_reusable_list = Fcons (Qnil, Qnil);
+staticpro (&Vextent_face_reusable_list);
+}
+void
+complex_vars_of_extents (void)
+{
+staticpro (&Vextent_face_memoize_hash_table);
+/* The memoize hash table maps from lists of symbols to lists of
+faces.  It needs to be `equal' to implement the memoization.
+The reverse table maps in the other direction and just needs
+to do `eq' comparison because the lists of faces are already
+memoized. */
+Vextent_face_memoize_hash_table =
+make_lisp_hash_table (100, HASH_TABLE_VALUE_WEAK, HASH_TABLE_EQUAL);
+staticpro (&Vextent_face_reverse_memoize_hash_table);
+Vextent_face_reverse_memoize_hash_table =
+make_lisp_hash_table (100, HASH_TABLE_KEY_WEAK, HASH_TABLE_EQ);
+}

Mercurial > hg > xemacs-beta

comparison src/extents.c @ 428:3ecd8885ac67 r21-2-22