xrpl_address_macro/
lib.rs

1use proc_macro::TokenStream;
2use quote::quote;
3use syn::{LitStr, parse_macro_input};
4
5/// Macro to convert an r-address to a 20-byte array at compile time.
6///
7/// # Example
8/// ```
9/// const ACCOUNT: [u8; 20] = r_address!("rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh");
10/// ```
11#[proc_macro]
12pub fn r_address(input: TokenStream) -> TokenStream {
13    let addr_lit = parse_macro_input!(input as LitStr);
14    let addr = addr_lit.value();
15
16    match decode_classic_address_to_20bytes(&addr) {
17        Some(bytes) => {
18            if bytes.len() != 20 {
19                return syn::Error::new(
20                    addr_lit.span(),
21                    format!("Address decoded to {} bytes, expected 20", bytes.len()),
22                )
23                .to_compile_error()
24                .into();
25            }
26
27            let bytes_tokens = bytes.iter().map(|b| quote! { #b });
28            let expanded = quote! {
29                [#(#bytes_tokens),*]
30            };
31
32            TokenStream::from(expanded)
33        }
34        None => syn::Error::new(addr_lit.span(), format!("Invalid r-address: {}", addr))
35            .to_compile_error()
36            .into(),
37    }
38}
39
40fn decode_classic_address_to_20bytes(addr: &str) -> Option<Vec<u8>> {
41    if !addr.starts_with('r') {
42        return None;
43    }
44    let alphabet =
45        bs58::Alphabet::new(b"rpshnaf39wBUDNEGHJKLM4PQRST7VWXYZ2bcdeCg65jkm8oFqi1tuvAxyz").ok()?;
46    let full = bs58::decode(addr)
47        .with_alphabet(&alphabet)
48        .into_vec()
49        .ok()?;
50    if full.len() < 1 + 20 + 4 {
51        return None;
52    }
53    // Version byte should be 0x00 for classic AccountID
54    if full[0] != 0x00 {
55        return None;
56    }
57    // Split payload and checksum
58    let (payload, checksum) = full.split_at(full.len() - 4);
59    // Verify checksum: double SHA-256 of payload, take first 4 bytes
60    use sha2::{Digest, Sha256};
61    let first = Sha256::digest(payload);
62    let second = Sha256::digest(&first);
63    if &second[0..4] != checksum {
64        return None;
65    }
66    // Payload is version (1) + 20 bytes account id
67    if payload.len() != 1 + 20 {
68        return None;
69    }
70    Some(payload[1..].to_vec())
71}
xrpl_address_macro/lib.rs

xrpl_address_macro/
lib.rs
