Note: The URL selector is stored in the output_buffer - which is currently 520 bytes. Beside all of the URL (apart from a potential "http://") the 'get' and the 'http_preamble' have to fit into that buffer. Therefore URLs mustn't exceed 450 chars. However, we omit a check to avoid further code size increase as most of the time URLs are known to be much shorter anyhow. If the URLs might become large we just leave it up to the user to check their length.
Together with the recent change to provide the inbound data buffer address and length to the TCP callback function as C parameters this change allows the TCP API to get along without any global variable :-)
In contrast to the multiple UDP callbacks there's only one TCP callback so it easy to provide a wrapper for the C callback that pushes C parameters on the stack.
The IP5 usage of ld65 segments and zeropage variables was made compatible with cc65 C programs already a while ago. This commit is the next logical step which is to introduce the actual C interface to IP65.
IP65 for C programs shares the the ip65.lib / ip65_tcp.lib with IP65 for assembler programs. However the various libraries from the 'drivers' are not reused. Instead there's exactly one library for every target named ip65_<target>.lib. Those libraries contain only functions used by ip65.lib / ip65_tcp.lib.
TODOs:
- Introduce c64_timer.s and atr_timer.s.
- Add a C interface to the rest of the IP65 functionality (especially TCP).
