Fix previous changes.

src/coding.c

@@ -744,17 +744,17 @@ static struct coding_system coding_categories[coding_category_max];
   } while (0)
 
 /* Safely get two bytes from the source text pointed by SRC which ends
-   at SRC_END, and set C1 and C2 to those bytes.  If there are not
-   enough bytes in the source for C1, it jumps to `no_more_source'.
-   If there are not enough bytes in the source for C2, set C2 to -1.
-   If multibytep is nonzero and a multibyte character is found at SRC,
-   set C1 and/or C2 to the negative value of the character code.  The
-   caller should declare and set these variables appropriately in
-   advance:
+   at SRC_END, and set C1 and C2 to those bytes while skipping the
+   heading multibyte characters.  If there are not enough bytes in the
+   source, it jumps to `no_more_source'.  If multibytep is nonzero and
+   a multibyte character is found for C2, set C2 to the negative value
+   of the character code.  The caller should declare and set these
+   variables appropriately in advance:
 	src, src_end, multibytep
    It is intended that this macro is used in detect_coding_utf_16.  */
 
 #define TWO_MORE_BYTES(c1, c2)				\
+  do {							\
     do {						\
       if (src == src_end)				\
 	goto no_more_source;				\
@@ -765,14 +765,13 @@ static struct coding_system coding_categories[coding_category_max];
 	    c1 = ((c1 & 1) << 6) | *src++;		\
 	  else						\
 	    {						\
-	    c1 = c2 = -1;			\
-	    break;				\
+	      src += BYTES_BY_CHAR_HEAD (c1) - 1;	\
+	      c1 = -1;					\
 	    }						\
 	}						\
+    } while (c1 < 0);					\
     if (src == src_end)					\
-      c2 = -1;					\
-    else					\
-      {						\
+      goto no_more_source;				\
     c2 = *src++;					\
     if (multibytep && (c2 & 0x80))			\
       {							\
@@ -781,7 +780,6 @@ static struct coding_system coding_categories[coding_category_max];
 	else						\
 	  c2 = -1;					\
       }							\
-      }						\
   } while (0)
 
 
@@ -1633,7 +1631,7 @@ detect_coding_utf_16 (coding, detect_info)
 				| CATEGORY_MASK_UTF_16_BE_NOSIG
 				| CATEGORY_MASK_UTF_16_LE_NOSIG);
     }
-  else if (c1 < 0 || c2 < 0)
+  else if (c2 < 0)
     {
       detect_info->rejected |= CATEGORY_MASK_UTF_16;
       return 0;
@@ -1656,7 +1654,7 @@ detect_coding_utf_16 (coding, detect_info)
       while (1)
 	{
 	  TWO_MORE_BYTES (c1, c2);
-	  if (c1 < 0 || c2 < 0)
+	  if (c2 < 0)
 	    break;
 	  if (! e[c1])
 	    {