(mu_is_proto): New function.

@@ -140,6 +140,8 @@ extern int mu_decode_filter (mu_stream_t *pfilter, mu_stream_t input,
 extern enum mu_iconv_fallback_mode mu_default_fallback_mode;
 extern int mu_set_default_fallback (const char *str);
 
+extern int mu_is_proto (const char *p);
+  
 #ifdef __cplusplus
 }
 #endif

@@ -1293,3 +1293,13 @@ mu_decode_filter (mu_stream_t *pfilter, mu_stream_t input,
   *pfilter = filter;
   return 0;
 }
+
+int
+mu_is_proto (const char *p)
+{
+  for (; *p && *p != '/'; p++)
+    if (*p == ':')
+      return 1;
+  return 0;
+}
+