1 files changed, 35 insertions, 14 deletions

diff --git a/src/coding.c b/src/coding.c
index a6cf9ce7844..c300ce20961 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -924,17 +924,22 @@ coding_set_destination (coding)
 {
   if (BUFFERP (coding->dst_object))
     {
-      /* We are sure that coding->dst_pos_byte is before the gap of the
-         buffer. */
-      coding->destination = (BUF_BEG_ADDR (XBUFFER (coding->dst_object))
-                             + coding->dst_pos_byte - 1);
       if (coding->src_pos < 0)
-        coding->dst_bytes = (GAP_END_ADDR
-                             - (coding->src_bytes - coding->consumed)
-                             - coding->destination);
+        {
+          coding->destination = BEG_ADDR + coding->dst_pos_byte - 1;
+          coding->dst_bytes = (GAP_END_ADDR
+                               - (coding->src_bytes - coding->consumed)
+                               - coding->destination);
+        }
       else
-        coding->dst_bytes = (BUF_GAP_END_ADDR (XBUFFER (coding->dst_object))
-                             - coding->destination);
+        {
+          /* We are sure that coding->dst_pos_byte is before the gap
+             of the buffer. */
+          coding->destination = (BUF_BEG_ADDR (XBUFFER (coding->dst_object))
+                                 + coding->dst_pos_byte - 1);
+          coding->dst_bytes = (BUF_GAP_END_ADDR (XBUFFER (coding->dst_object))
+                               - coding->destination);
+        }
     }
   else
     /* Otherwise, the destination is C string and is never relocated
@@ -1223,9 +1228,17 @@ encode_coding_utf_8 (coding)
           
           ASSURE_DESTINATION (safe_room);
           c = *charbuf++;
-          CHAR_STRING_ADVANCE (c, pend);
-          for (p = str; p < pend; p++)
-            EMIT_ONE_BYTE (*p);
+          if (CHAR_BYTE8_P (c))
+            {
+              c = CHAR_TO_BYTE8 (c);
+              EMIT_ONE_BYTE (c);
+            }
+          else
+            {
+              CHAR_STRING_ADVANCE (c, pend);
+              for (p = str; p < pend; p++)
+                EMIT_ONE_BYTE (*p);
+            }
         }
     }
   else
@@ -6115,8 +6128,16 @@ encode_coding_object (coding, src_object, from, from_byte, to, to_byte,
   if (BUFFERP (dst_object))
     {
       coding->dst_object = dst_object;
-      coding->dst_pos = BUF_PT (XBUFFER (dst_object));
-      coding->dst_pos_byte = BUF_PT_BYTE (XBUFFER (dst_object));
+      if (EQ (src_object, dst_object))
+        {
+          coding->dst_pos = from;
+          coding->dst_pos_byte = from_byte;
+        }
+      else
+        {
+          coding->dst_pos = BUF_PT (XBUFFER (dst_object));
+          coding->dst_pos_byte = BUF_PT_BYTE (XBUFFER (dst_object));
+        }
       coding->dst_multibyte
         = ! NILP (XBUFFER (dst_object)->enable_multibyte_characters);
     }