c-rgb

This is a very basic library that allows C code to call rgb's functions to parse and validate RGB transactions (or proofs as we generally call them).

The trickiest part of this library is memory management: should the C "side" pre-allocate buffers and then simply ask the Rust "side" to fill them or the other way around?

The current version is implemented keeping in mind these rules:

• All the data structures that might need to be stored or somehow changed in the C side are allocated there. This includes simple data structures, like rgb_sha256d, rgb_bitcoin_outpoint, rgb_needed_tx, and some more complex ones like rgb_contract, rgb_proof.

• Answers to "queries" made from the C side are allocated in Rust: this is because in most cases some variable-length buffers and arrays are returned (like Vec<NeededTx> for {contract,proof}.get_needed_txs() or Vec<OP_CODE> for {contract,proof}.get_expected_script()). In these cases we don't expect the C side to really do anything with, other than reading, the results (like storing them or sending them over the network), so we can let Rust allocate and handle them as he prefers. Please remember that in this case it would still be C's responsibility to manually free the memory allocated by Rust.

IMPORTANT NOTE: these rules are the ones that look the most reasonable now. We might change them in the future if we realize that there are best ways to do it. We don't consider these APIs to be stable at all. Ideally we would like everything to follow the first rule (allocate the memory in the C side), but this looks kinda complicated in some cases.

Build and running the examples

• ./configure
• make

This will build the Rust layer first, and then some binaries in the examples/build/* folder that can be run to demonstrate some features of this library.

These examples are statically-linked so that they can be run without either installing the shared objects on your system or having to deal with weird LD_LIBRARY paths. You might need to install additional libraries on your system to build the examples, like the static version of glibc which might not be available by default.