Crash when receiving raw unicode data

[fdgStilla]

I'm using anyrpc as a c++ RPC server and xmlrcp as a python client.

When I send a unicode string using xmlrcp, the string is sent with the UTF8 bytes (for exemple "ā" is sent as 0xC4 0x81 (which is -60, -127 in char).

Maybe this is an error from xmlrcp not to convert the UTF8 bytes to escaped xml characters like expected by anyrpc (&#C4&#81 I guess?), but anyway the software shall not crash when receiving this data.

The error is in Reader::IsWhiteSpace, it uses std::isspace which does not support negative signed char, see the official documentation: https://en.cppreference.com/w/cpp/string/byte/isspace