Fix sexp-conv assertion failure, reported by Hanno Böck.

ChangeLog

 2016-02-16  Niels Möller  <nisse@lysator.liu.se>
 
+	* tools/input.c (sexp_get_string_length): Process advanced string
+	syntax only when in advanced mode. Fixes an assertion failure
+	reported by Hanno Böck, for input where advanced syntax is
+	improperly wrapped inside transport syntax.
+
 	* tools/parse.c (sexp_parse): Fail with an error message for
 	unexpected ']' characters. Fixes crash reported by Hanno Böck.
 	Also handle SEXP_DISPLAY (internal error) explicitly, without a

tools/input.c

@@ -286,9 +286,7 @@ sexp_get_string_length(struct sexp_input *input, enum sexp_mode mode,
 	}
     }
 
-  switch(input->c)
-    {
-    case ':':
+  if (input->c == ':')
     /* Verbatim */
     for (; length; length--)
       {
@@ -296,12 +294,13 @@ sexp_get_string_length(struct sexp_input *input, enum sexp_mode mode,
 	sexp_push_char(input, string);
       }
 
-      break;
+  else if (mode != SEXP_ADVANCED)
+    die("Encountered advanced string in canonical mode.\n");
 
+  else
+    switch(input->c)
+      {
       case '"':
-      if (mode != SEXP_ADVANCED)
-	die("Encountered quoted string in canonical mode.\n");
-
 	for (; length; length--)
 	  if (sexp_get_quoted_char(input))
 	    sexp_push_char(input, string);