* buffer.h (struct buffer_text): New field chars_modiff.

        (CHARS_MODIFF, BUF_CHARS_MODIFF): New macros.
        * buffer.c (Fbuffer_chars_modified_tick): New function returning
        value of BUF_CHARS_MODIFF.
        (syms_of_buffer): Defsubr it.
        (Fget_buffer_create): Initialize BUF_CHARS_MODIFF.
        * insdel.c (modify_region): New argument preserve_chars_modiff.
        Set CHARS_MODIFF to MODIFF provided preserve_chars_modiff is zero.
        (insert_1_both, insert_from_string_1, insert_from_buffer_1)
        (adjust_after_replace, adjust_after_replace_noundo)
        (replace_range, replace_range_2, del_range_2): Reset CHARS_MODIFF.
        * lisp.h (modify_region): Add fourth argument in extern.
        * casefiddle.c (casify_region): Call modify_region with fourth
        argument zero to assert that CHARS_MODIFF is updated.
        * editfns.c (Fsubst_char_in_region, Ftranslate_region_internal)
        (Ftranspose_regions): Likewise.
        * textprop.c (Fadd_text_properties, Fset_text_properties)
        (Fremove_text_properties, Fremove_list_of_text_properties):
        Call modify_region with fourth argument 1 to avoid that
        CHARS_MODIFF is updated.

8 files changed, 91 insertions, 18 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index f0f8ebf9d79..f2395388d0f 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,26 @@
+2006-08-03  Martin Rudalics  <address@hidden>
+
+        * buffer.h (struct buffer_text): New field chars_modiff.
+        (CHARS_MODIFF, BUF_CHARS_MODIFF): New macros.
+        * buffer.c (Fbuffer_chars_modified_tick): New function returning
+        value of BUF_CHARS_MODIFF.
+        (syms_of_buffer): Defsubr it.
+        (Fget_buffer_create): Initialize BUF_CHARS_MODIFF.
+        * insdel.c (modify_region): New argument preserve_chars_modiff.
+        Set CHARS_MODIFF to MODIFF provided preserve_chars_modiff is zero.
+        (insert_1_both, insert_from_string_1, insert_from_buffer_1)
+        (adjust_after_replace, adjust_after_replace_noundo)
+        (replace_range, replace_range_2, del_range_2): Reset CHARS_MODIFF.
+        * lisp.h (modify_region): Add fourth argument in extern.
+        * casefiddle.c (casify_region): Call modify_region with fourth
+        argument zero to assert that CHARS_MODIFF is updated.
+        * editfns.c (Fsubst_char_in_region, Ftranslate_region_internal)
+        (Ftranspose_regions): Likewise.
+        * textprop.c (Fadd_text_properties, Fset_text_properties)
+        (Fremove_text_properties, Fremove_list_of_text_properties):
+        Call modify_region with fourth argument 1 to avoid that
+        CHARS_MODIFF is updated.
+
 2006-08-31  Richard Stallman  <rms@gnu.org>
 
 	* editfns.c (Fformat): Don't sign-extend for %o or %x.
diff --git a/src/buffer.c b/src/buffer.c
index 863b217d2b4..58c047a87ba 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -374,6 +374,7 @@ The value is never nil.  */)
   BUF_ZV_BYTE (b) = BEG_BYTE;
   BUF_Z_BYTE (b) = BEG_BYTE;
   BUF_MODIFF (b) = 1;
+  BUF_CHARS_MODIFF (b) = 1;
   BUF_OVERLAY_MODIFF (b) = 1;
   BUF_SAVE_MODIFF (b) = 1;
   BUF_INTERVALS (b) = 0;
@@ -1148,6 +1149,31 @@ No argument or nil as argument means use current buffer as BUFFER.  */)
 
   return make_number (BUF_MODIFF (buf));
 }
+
+DEFUN ("buffer-chars-modified-tick", Fbuffer_chars_modified_tick,
+       Sbuffer_chars_modified_tick, 0, 1, 0,
+       doc: /* Return BUFFER's character-change tick counter.
+Each buffer has a character-change tick counter, which is set to the
+value of the buffer's tick counter \(see `buffer-modified-tick'), each
+time text in that buffer is inserted or deleted.  By comparing the
+values returned by two individual calls of buffer-chars-modified-tick,
+you can tell whether a character change occurred in that buffer in
+between these calls.  No argument or nil as argument means use current
+buffer as BUFFER.  */)
+     (buffer)
+     register Lisp_Object buffer;
+{
+  register struct buffer *buf;
+  if (NILP (buffer))
+    buf = current_buffer;
+  else
+    {
+      CHECK_BUFFER (buffer);
+      buf = XBUFFER (buffer);
+    }
+
+  return make_number (BUF_CHARS_MODIFF (buf));
+}
 
 DEFUN ("rename-buffer", Frename_buffer, Srename_buffer, 1, 2,
        "sRename buffer (to new name): \nP",
@@ -6044,6 +6070,7 @@ The function `kill-all-local-variables' runs this before doing anything else.  *
   defsubr (&Sbuffer_modified_p);
   defsubr (&Sset_buffer_modified_p);
   defsubr (&Sbuffer_modified_tick);
+  defsubr (&Sbuffer_chars_modified_tick);
   defsubr (&Srename_buffer);
   defsubr (&Sother_buffer);
   defsubr (&Sbuffer_enable_undo);
diff --git a/src/buffer.h b/src/buffer.h
index efe0252453a..a5f8a6a4070 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -82,6 +82,9 @@ Boston, MA 02110-1301, USA.  */
 /* Modification count.  */
 #define MODIFF (current_buffer->text->modiff)
 
+/* Character modification count.  */
+#define CHARS_MODIFF (current_buffer->text->chars_modiff)
+
 /* Overlay modification count.  */
 #define OVERLAY_MODIFF (current_buffer->text->overlay_modiff)
 
@@ -147,6 +150,9 @@ Boston, MA 02110-1301, USA.  */
 /* Modification count.  */
 #define BUF_MODIFF(buf) ((buf)->text->modiff)
 
+/* Character modification count.  */
+#define BUF_CHARS_MODIFF(buf) ((buf)->text->chars_modiff)
+
 /* Modification count as of last visit or save.  */
 #define BUF_SAVE_MODIFF(buf) ((buf)->text->save_modiff)
 
@@ -406,6 +412,10 @@ struct buffer_text
 				   for this buffer.  It is incremented for
 				   each such event, and never otherwise
 				   changed.  */
+    int chars_modiff;           /* This is modified with character change
+				   events for this buffer.  It is set to
+				   modiff for each such event, and never
+				   otherwise changed.  */
     int save_modiff;		/* Previous value of modiff, as of last
 				   time buffer visited or saved a file.  */
 
diff --git a/src/casefiddle.c b/src/casefiddle.c
index 0ad884310ed..cb7c953a3e4 100644
--- a/src/casefiddle.c
+++ b/src/casefiddle.c
@@ -187,7 +187,7 @@ casify_region (flag, b, e)
   validate_region (&b, &e);
   start = XFASTINT (b);
   end = XFASTINT (e);
-  modify_region (current_buffer, start, end);
+  modify_region (current_buffer, start, end, 0);
   record_change (start, end - start);
   start_byte = CHAR_TO_BYTE (start);
   end_byte = CHAR_TO_BYTE (end);
diff --git a/src/editfns.c b/src/editfns.c
index e916b505fe8..2c392df564e 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -2781,7 +2781,7 @@ Both characters must have the same length of multi-byte form.  */)
 	  else if (!changed)
 	    {
 	      changed = -1;
-	      modify_region (current_buffer, pos, XINT (end));
+	      modify_region (current_buffer, pos, XINT (end), 0);
 
 	      if (! NILP (noundo))
 		{
@@ -2897,7 +2897,7 @@ It returns the number of characters changed.  */)
   pos = XINT (start);
   pos_byte = CHAR_TO_BYTE (pos);
   end_pos = XINT (end);
-  modify_region (current_buffer, pos, XINT (end));
+  modify_region (current_buffer, pos, XINT (end), 0);
 
   cnt = 0;
   for (; pos < end_pos; )
@@ -4168,7 +4168,7 @@ Transposing beyond buffer boundaries is an error.  */)
 
   if (end1 == start2)		/* adjacent regions */
     {
-      modify_region (current_buffer, start1, end2);
+      modify_region (current_buffer, start1, end2, 0);
       record_change (start1, len1 + len2);
 
       tmp_interval1 = copy_intervals (cur_intv, start1, len1);
@@ -4224,8 +4224,8 @@ Transposing beyond buffer boundaries is an error.  */)
         {
 	  USE_SAFE_ALLOCA;
 
-          modify_region (current_buffer, start1, end1);
-          modify_region (current_buffer, start2, end2);
+          modify_region (current_buffer, start1, end1, 0);
+          modify_region (current_buffer, start2, end2, 0);
           record_change (start1, len1);
           record_change (start2, len2);
           tmp_interval1 = copy_intervals (cur_intv, start1, len1);
@@ -4254,7 +4254,7 @@ Transposing beyond buffer boundaries is an error.  */)
         {
 	  USE_SAFE_ALLOCA;
 
-          modify_region (current_buffer, start1, end2);
+          modify_region (current_buffer, start1, end2, 0);
           record_change (start1, (end2 - start1));
           tmp_interval1 = copy_intervals (cur_intv, start1, len1);
           tmp_interval_mid = copy_intervals (cur_intv, end1, len_mid);
@@ -4285,7 +4285,7 @@ Transposing beyond buffer boundaries is an error.  */)
 	  USE_SAFE_ALLOCA;
 
           record_change (start1, (end2 - start1));
-          modify_region (current_buffer, start1, end2);
+          modify_region (current_buffer, start1, end2, 0);
 
           tmp_interval1 = copy_intervals (cur_intv, start1, len1);
           tmp_interval_mid = copy_intervals (cur_intv, end1, len_mid);
diff --git a/src/insdel.c b/src/insdel.c
index b97539c1cc2..bd6e30d9449 100644
--- a/src/insdel.c
+++ b/src/insdel.c
@@ -1007,6 +1007,7 @@ insert_1_both (string, nchars, nbytes, inherit, prepare, before_markers)
      will add up to the right stuff in the undo list.  */
   record_insert (PT, nchars);
   MODIFF++;
+  CHARS_MODIFF = MODIFF;
 
   bcopy (string, GPT_ADDR, nbytes);
 
@@ -1144,6 +1145,7 @@ insert_from_string_1 (string, pos, pos_byte, nchars, nbytes,
 
   record_insert (PT, nchars);
   MODIFF++;
+  CHARS_MODIFF = MODIFF;
 
   GAP_SIZE -= outgoing_nbytes;
   GPT += nchars;
@@ -1295,6 +1297,7 @@ insert_from_buffer_1 (buf, from, nchars, inherit)
 
   record_insert (PT, nchars);
   MODIFF++;
+  CHARS_MODIFF = MODIFF;
 
   GAP_SIZE -= outgoing_nbytes;
   GPT += nchars;
@@ -1403,6 +1406,7 @@ adjust_after_replace (from, from_byte, prev_text, len, len_byte)
   if (len == 0)
     evaporate_overlays (from);
   MODIFF++;
+  CHARS_MODIFF = MODIFF;
 }
 
 /* Like adjust_after_replace, but doesn't require PREV_TEXT.
@@ -1453,6 +1457,7 @@ adjust_after_replace_noundo (from, from_byte, nchars_del, nbytes_del, len, len_b
   if (len == 0)
     evaporate_overlays (from);
   MODIFF++;
+  CHARS_MODIFF = MODIFF;
 }
 
 /* Record undo information, adjust markers and position keepers for an
@@ -1645,6 +1650,7 @@ replace_range (from, to, new, prepare, inherit, markers)
   CHECK_MARKERS ();
 
   MODIFF++;
+  CHARS_MODIFF = MODIFF;
   UNGCPRO;
 
   signal_after_change (from, nchars_del, GPT - from);
@@ -1769,6 +1775,7 @@ replace_range_2 (from, from_byte, to, to_byte, ins, inschars, insbytes, markers)
   CHECK_MARKERS ();
 
   MODIFF++;
+  CHARS_MODIFF = MODIFF;
 }
 
 /* Delete characters in current buffer
@@ -1950,6 +1957,7 @@ del_range_2 (from, from_byte, to, to_byte, ret_string)
   if (! EQ (current_buffer->undo_list, Qt))
     record_delete (from, deletion);
   MODIFF++;
+  CHARS_MODIFF = MODIFF;
 
   /* Relocate point as if it were a marker.  */
   if (from < PT)
@@ -1990,12 +1998,15 @@ del_range_2 (from, from_byte, to, to_byte, ret_string)
    character positions START to END.  This checks the read-only
    properties of the region, calls the necessary modification hooks,
    and warns the next redisplay that it should pay attention to that
-   area.  */
+   area.
+
+   If PRESERVE_CHARS_MODIFF is non-zero, do not update CHARS_MODIFF.
+   Otherwise set CHARS_MODIFF to the new value of MODIFF.  */
 
 void
-modify_region (buffer, start, end)
+modify_region (buffer, start, end, preserve_chars_modiff)
      struct buffer *buffer;
-     int start, end;
+     int start, end, preserve_chars_modiff;
 {
   struct buffer *old_buffer = current_buffer;
 
@@ -2009,6 +2020,8 @@ modify_region (buffer, start, end)
   if (MODIFF <= SAVE_MODIFF)
     record_first_change ();
   MODIFF++;
+  if (! preserve_chars_modiff)
+    CHARS_MODIFF = MODIFF;
 
   buffer->point_before_scroll = Qnil;
 
diff --git a/src/lisp.h b/src/lisp.h
index 0fb14136a53..3d7870c4867 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -2471,7 +2471,7 @@ extern Lisp_Object del_range_1 P_ ((int, int, int, int));
 extern void del_range_byte P_ ((int, int, int));
 extern void del_range_both P_ ((int, int, int, int, int));
 extern Lisp_Object del_range_2 P_ ((int, int, int, int, int));
-extern void modify_region P_ ((struct buffer *, int, int));
+extern void modify_region P_ ((struct buffer *, int, int, int));
 extern void prepare_to_modify_buffer P_ ((int, int, int *));
 extern void signal_before_change P_ ((int, int, int *));
 extern void signal_after_change P_ ((int, int, int));
diff --git a/src/textprop.c b/src/textprop.c
index fd70f039d22..785ed19b566 100644
--- a/src/textprop.c
+++ b/src/textprop.c
@@ -1253,7 +1253,7 @@ Return t if any property value actually changed, nil otherwise.  */)
     }
 
   if (BUFFERP (object))
-    modify_region (XBUFFER (object), XINT (start), XINT (end));
+    modify_region (XBUFFER (object), XINT (start), XINT (end), 1);
 
   /* We are at the beginning of interval I, with LEN chars to scan.  */
   for (;;)
@@ -1393,7 +1393,7 @@ set_text_properties (start, end, properties, object, signal_after_change_p)
     }
 
   if (BUFFERP (object))
-    modify_region (XBUFFER (object), XINT (start), XINT (end));
+    modify_region (XBUFFER (object), XINT (start), XINT (end), 1);
 
   set_text_properties_1 (start, end, properties, object, i);
 
@@ -1541,7 +1541,7 @@ Use set-text-properties if you want to remove all text properties.  */)
     }
 
   if (BUFFERP (object))
-    modify_region (XBUFFER (object), XINT (start), XINT (end));
+    modify_region (XBUFFER (object), XINT (start), XINT (end), 1);
 
   /* We are at the beginning of an interval, with len to scan */
   for (;;)
@@ -1655,7 +1655,7 @@ Return t if any property was actually removed, nil otherwise.  */)
 	  if (LENGTH (i) == len)
 	    {
 	      if (!modified && BUFFERP (object))
-		modify_region (XBUFFER (object), XINT (start), XINT (end));
+		modify_region (XBUFFER (object), XINT (start), XINT (end), 1);
 	      remove_properties (Qnil, properties, i, object);
 	      if (BUFFERP (object))
 		signal_after_change (XINT (start), XINT (end) - XINT (start),
@@ -1668,7 +1668,7 @@ Return t if any property was actually removed, nil otherwise.  */)
 	  i = split_interval_left (i, len);
 	  copy_properties (unchanged, i);
 	  if (!modified && BUFFERP (object))
-	    modify_region (XBUFFER (object), XINT (start), XINT (end));
+	    modify_region (XBUFFER (object), XINT (start), XINT (end), 1);
 	  remove_properties (Qnil, properties, i, object);
 	  if (BUFFERP (object))
 	    signal_after_change (XINT (start), XINT (end) - XINT (start),
@@ -1679,7 +1679,7 @@ Return t if any property was actually removed, nil otherwise.  */)
       if (interval_has_some_properties_list (properties, i))
 	{
 	  if (!modified && BUFFERP (object))
-	    modify_region (XBUFFER (object), XINT (start), XINT (end));
+	    modify_region (XBUFFER (object), XINT (start), XINT (end), 1);
 	  remove_properties (Qnil, properties, i, object);
 	  modified = 1;
 	}