Add transparent address decode

zcash_client_backend/src/encoding.rs

@@ -9,9 +9,10 @@ use bech32::{self, Error, FromBase32, ToBase32};
 use pairing::bls12_381::Bls12;
 use std::io::{self, Write};
 use zcash_primitives::{
-    primitives::{PaymentAddress},
+    primitives::PaymentAddress,
     zip32::{ExtendedFullViewingKey, ExtendedSpendingKey},
     JUBJUB,
+    legacy::TransparentAddress,
 };
 
 fn bech32_encode<F>(hrp: &str, write: F) -> String
@@ -176,6 +177,63 @@ pub fn decode_payment_address(hrp: &str, s: &str) -> Result<Option<PaymentAddres
     })
 }
 
+
+/// Decodes a [`TransparentAddress`] from a Base58Check-encoded string.
+///
+/// # Examples
+///
+/// ```
+/// use zcash_client_backend::{
+///     constants::testnet::{B58_PUBKEY_ADDRESS_PREFIX, B58_SCRIPT_ADDRESS_PREFIX},
+///     encoding::decode_transparent_address,
+/// };
+/// use zcash_primitives::legacy::TransparentAddress;
+///
+/// assert_eq!(
+///     decode_transparent_address(
+///         &B58_PUBKEY_ADDRESS_PREFIX,
+///         &B58_SCRIPT_ADDRESS_PREFIX,
+///         "tm9iMLAuYMzJ6jtFLcA7rzUmfreGuKvr7Ma",
+///     ),
+///     Ok(Some(TransparentAddress::PublicKey([0; 20]))),
+/// );
+///
+/// assert_eq!(
+///     decode_transparent_address(
+///         &B58_PUBKEY_ADDRESS_PREFIX,
+///         &B58_SCRIPT_ADDRESS_PREFIX,
+///         "t26YoyZ1iPgiMEWL4zGUm74eVWfhyDMXzY2",
+///     ),
+///     Ok(Some(TransparentAddress::Script([0; 20]))),
+/// );
+/// ```
+pub fn decode_transparent_address(
+    pubkey_version: &[u8],
+    script_version: &[u8],
+    s: &str,
+) -> Result<Option<TransparentAddress>, bs58::decode::Error> {
+    let decoded = bs58::decode(s).with_check(None).into_vec()?;
+    if &decoded[..pubkey_version.len()] == pubkey_version {
+        if decoded.len() == pubkey_version.len() + 20 {
+            let mut data = [0; 20];
+            data.copy_from_slice(&decoded[pubkey_version.len()..]);
+            Ok(Some(TransparentAddress::PublicKey(data)))
+        } else {
+            Ok(None)
+        }
+    } else if &decoded[..script_version.len()] == script_version {
+        if decoded.len() == script_version.len() + 20 {
+            let mut data = [0; 20];
+            data.copy_from_slice(&decoded[script_version.len()..]);
+            Ok(Some(TransparentAddress::Script(data)))
+        } else {
+            Ok(None)
+        }
+    } else {
+        Ok(None)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use pairing::bls12_381::Bls12;

zcash_client_backend/src/proto/mod.rs

@@ -1,6 +1,6 @@
 //! Generated code for handling light client protobuf structs.
 
-use ff::{PrimeField};
+use ff::PrimeField;
 use pairing::bls12_381::{Bls12, Fr, FrRepr};
 use zcash_primitives::{
     block::{BlockHash, BlockHeader},