* 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.

1 files changed, 10 insertions, 0 deletions

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.  */