I got a crash/exception on line 223 when calling std::ostream::write(char *, size_t) with buffers of unknown size (coming from libcurl during an HTTP request). By instead iterating the buffer myself and calling libc's putchar or libstdc++'s std::ostream::operator<<(char), there was no crash/exception.

I believe this might be due to the loop check on line 221 not checking for a possible early null-termination. A possible fix would be:

while (*tmp && i < len)