Move parse_subaddress_lookahead() from simplewallet.cpp to util.cpp

src/common/util.cpp

@@ -827,4 +827,22 @@ std::string get_nix_version_display_string()
       return false;
     return true;
   }
+
+  boost::optional<std::pair<uint32_t, uint32_t>> parse_subaddress_lookahead(const std::string& str)
+  {
+    auto pos = str.find(":");
+    bool r = pos != std::string::npos;
+    uint32_t major;
+    r = r && epee::string_tools::get_xtype_from_string(major, str.substr(0, pos));
+    uint32_t minor;
+    r = r && epee::string_tools::get_xtype_from_string(minor, str.substr(pos + 1));
+    if (r)
+    {
+      return std::make_pair(major, minor);
+    }
+    else
+    {
+      return {};
+    }
+  }
 }