Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

Returns true if the message is complete.

bool
is_done() const;

The message is complete after the full header is prduced and one of the following is true:

The skip body option was set.
The semantics of the message indicate there is no body.
The semantics of the message indicate a body is expected, and the entire body was parsed.