Slightly improve LZW_CLEAR handling.

* src/lzw/ftzopen.c (ft_lzwstate_io) <FT_LZW_PHASE_CODE>:
Ensure that subsequent (modulo garbage byte(s)) LZW_CLEAR codes are
handled as clear codes.  This also re-sets old_code and old_char to
predictable values, which is a little better than using `random'
ones if the code following LZW_CLEAR is invalid.

ChangeLog

@@ -1,3 +1,13 @@
+2011-09-11  Tomas Hoger  <thoger@redhat.com>
+
+	Slightly improve LZW_CLEAR handling.
+
+	* src/lzw/ftzopen.c (ft_lzwstate_io) <FT_LZW_PHASE_CODE>:
+	Ensure that subsequent (modulo garbage byte(s)) LZW_CLEAR codes are
+	handled as clear codes.  This also re-sets old_code and old_char to
+	predictable values, which is a little better than using `random'
+	ones if the code following LZW_CLEAR is invalid.
+
 2011-09-11  Tomas Hoger  <thoger@redhat.com>
 
 	Add explicit LZW decompression stack size limit.

src/lzw/ftzopen.c

@@ -321,11 +321,12 @@
           /* why not LZW_FIRST-256 ? */
           state->free_ent  = ( LZW_FIRST - 1 ) - 256;
           state->buf_clear = 1;
-          c = ft_lzwstate_get_code( state );
-          if ( c < 0 )
-            goto Eof;
 
-          code = (FT_UInt)c;
+          /* not quite right, but at least more predictable */
+          old_code = 0;
+          old_char = 0;
+
+          goto NextCode;
         }
 
         in_code = code; /* save code for later */