(map_charset_chars): For a charset of `superset'

method, fix calculation of code range.

2 files changed, 5 insertions, 2 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index f5cc4463bea..49936d11a5f 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,8 @@
 2009-04-09  Kenichi Handa  <handa@m17n.org>
 
+        * charset.c (map_charset_chars): For a charset of `superset'
+        method, fix calculation of code range.
+
         * font.c (font_put_extra): If VAL is nil, delete the slot for PROP
         from the list of extra properties.
         (font_clear_prop): Be sure to delete `:name' font property.
diff --git a/src/charset.c b/src/charset.c
index 54602ebe21d..492849f6868 100644
--- a/src/charset.c
+++ b/src/charset.c
@@ -809,8 +809,8 @@ map_charset_chars (c_function, function, arg,
 
           charset = CHARSET_FROM_ID (XFASTINT (XCAR (XCAR (parents))));
           offset = XINT (XCDR (XCAR (parents)));
-          this_from = from - offset;
-          this_to = to - offset;
+          this_from = from > offset ? from - offset : 0;
+          this_to = to > offset ? to - offset : 0;
           if (this_from < CHARSET_MIN_CODE (charset))
             this_from = CHARSET_MIN_CODE (charset);
           if (this_to > CHARSET_MAX_CODE (charset))