(CODING_SPEC_ISO_PLANE_CHARSET): Return -1 if no

character set is invoked to PLANE.
(struct coding_system): New member character_unification_table.

1 files changed, 8 insertions, 3 deletions

diff --git a/src/coding.h b/src/coding.h
index 3facc43547b..43929ad4655 100644
--- a/src/coding.h
+++ b/src/coding.h
@@ -175,9 +175,11 @@ struct iso2022_spec
 
 /* Return a charset which is currently designated to the graphic plane
    PLANE in the coding-system CODING.  */
-#define CODING_SPEC_ISO_PLANE_CHARSET(coding, plane) \
-  CODING_SPEC_ISO_DESIGNATION            \
-  (coding, CODING_SPEC_ISO_INVOCATION (coding, plane))
+#define CODING_SPEC_ISO_PLANE_CHARSET(coding, plane)    \
+  ((CODING_SPEC_ISO_INVOCATION (coding, plane) < 0)     \
+   ? -1                                                 \
+   : CODING_SPEC_ISO_DESIGNATION (coding,               \
+                                  CODING_SPEC_ISO_INVOCATION (coding, plane)))
 
 /*** BIG5 section ***/
 
@@ -288,6 +290,9 @@ struct coding_system
      additional conversion. */
   Lisp_Object pre_write_conversion;
 
+  /* Character unification table to look up, or nil.  */
+  Lisp_Object character_unification_table;
+
   /* Carryover yielded by decoding/encoding incomplete source.  No
      coding-system yields more than 7-byte of carryover.  This does
      not include a text which is not processed because of short of