1 files changed, 78 insertions, 0 deletions
diff --git a/vendor/crypto-bigint/src/uint/encoding/rlp.rs b/vendor/crypto-bigint/src/uint/encoding/rlp.rs
new file mode 100644
index 0000000..112efb1
--- /dev/null
+++ b/vendor/crypto-bigint/src/uint/encoding/rlp.rs
@@ -0,0 +1,78 @@
+//! Recursive Length Prefix (RLP) encoding support.
+
+use crate::{Encoding, Uint};
+use rlp::{DecoderError, Rlp, RlpStream};
+
+impl<const LIMBS: usize> rlp::Encodable for Uint<LIMBS>
+where
+    Self: Encoding,
+{
+    fn rlp_append(&self, stream: &mut RlpStream) {
+        let bytes = self.to_be_bytes();
+        let mut bytes_stripped = bytes.as_ref();
+
+        while bytes_stripped.first().cloned() == Some(0) {
+            bytes_stripped = &bytes_stripped[1..];
+        }
+
+        stream.encoder().encode_value(bytes_stripped);
+    }
+}
+
+impl<const LIMBS: usize> rlp::Decodable for Uint<LIMBS>
+where
+    Self: Encoding,
+    <Self as Encoding>::Repr: Default,
+{
+    fn decode(rlp: &Rlp<'_>) -> Result<Self, DecoderError> {
+        rlp.decoder().decode_value(|bytes| {
+            if bytes.first().cloned() == Some(0) {
+                Err(rlp::DecoderError::RlpInvalidIndirection)
+            } else {
+                let mut repr = <Self as Encoding>::Repr::default();
+                let offset = repr
+                    .as_ref()
+                    .len()
+                    .checked_sub(bytes.len())
+                    .ok_or(DecoderError::RlpIsTooBig)?;
+
+                repr.as_mut()[offset..].copy_from_slice(bytes);
+                Ok(Self::from_be_bytes(repr))
+            }
+        })
+    }
+}
+
+#[cfg(test)]
+#[allow(clippy::unwrap_used)]
+mod tests {
+    use crate::U256;
+    use hex_literal::hex;
+
+    /// U256 test vectors from the `rlp` crate.
+    ///
+    /// <https://github.com/paritytech/parity-common/blob/faad8b6/rlp/tests/tests.rs#L216-L222>
+    const U256_VECTORS: &[(U256, &[u8])] = &[
+        (U256::ZERO, &hex!("80")),
+        (
+            U256::from_be_hex("0000000000000000000000000000000000000000000000000000000001000000"),
+            &hex!("8401000000"),
+        ),
+        (
+            U256::from_be_hex("00000000000000000000000000000000000000000000000000000000ffffffff"),
+            &hex!("84ffffffff"),
+        ),
+        (
+            U256::from_be_hex("8090a0b0c0d0e0f00910203040506077000000000000000100000000000012f0"),
+            &hex!("a08090a0b0c0d0e0f00910203040506077000000000000000100000000000012f0"),
+        ),
+    ];
+
+    #[test]
+    fn round_trip() {
+        for &(uint, expected_bytes) in U256_VECTORS {
+            assert_eq!(rlp::encode(&uint), expected_bytes);
+            assert_eq!(rlp::decode::<U256>(expected_bytes).unwrap(), uint);
+        }
+    }
+}