Audit Fixes for RLP library on Broadcaster Audit

contracts/utils/RLP.sol

@@ -121,14 +121,11 @@ library RLP {
         }
     }
 
-    /// @dev Encode an address as RLP.
+    /// @dev Encode an address as RLP. The address is encoded as an uint256 to avoid leading zeros.
     function encode(address input) internal pure returns (bytes memory result) {
-        assembly ("memory-safe") {
-            result := mload(0x40)
-            mstore(result, 0x15) // length of the encoded data: 1 (prefix) + 0x14 (address)
-            mstore(add(result, 0x20), or(shl(248, 0x94), shl(88, input))) // prefix (0x94 = SHORT_OFFSET + 0x14) + input
-            mstore(0x40, add(result, 0x35)) // reserve memory
-        }
+        uint256 inputAsScalar = uint256(uint160(input));
+
+        return encode(inputAsScalar);
     }
 
     /// @dev Encode a uint256 as RLP.
@@ -167,13 +164,17 @@ library RLP {
         return encode(bytes(input));
     }
 
-    /// @dev Encode an array of bytes as RLP.
+    /**
+     * @dev Encode an array of bytes as RLP.
+     * This function expects an array of already encoded bytes, not raw bytes.
+     * Users should call {encode} on each element of the array before calling it.
+     */
     function encode(bytes[] memory input) internal pure returns (bytes memory) {
         return _encode(input.concat(), LONG_OFFSET);
     }
 
     /// @dev Encode an encoder (list of bytes) as RLP
-    function encode(Encoder memory self) internal pure returns (bytes memory result) {
+    function encode(Encoder memory self) internal pure returns (bytes memory) {
         return _encode(self.acc.flatten(), LONG_OFFSET);
     }
 
@@ -215,8 +216,6 @@ library RLP {
 
     /// @dev Decode an RLP encoded address. See {encode-address}
     function readAddress(Memory.Slice item) internal pure returns (address) {
-        uint256 length = item.length();
-        require(length == 1 || length == 21, RLPInvalidEncoding());
         return address(uint160(readUint256(item)));
     }
 
@@ -241,7 +240,7 @@ library RLP {
         (uint256 offset, uint256 length, ItemType itemType) = _decodeLength(item);
         require(itemType == ItemType.Data, RLPInvalidEncoding());
 
-        // Length is checked by {toBytes}
+        // Length is checked by {slice}
         return item.slice(offset, length).toBytes();
     }
 
@@ -326,9 +325,7 @@ library RLP {
      * @dev Decodes an RLP `item`'s `length and type from its prefix.
      * Returns the offset, length, and type of the RLP item based on the encoding rules.
      */
-    function _decodeLength(
-        Memory.Slice item
-    ) private pure returns (uint256 _offset, uint256 _length, ItemType _itemtype) {
+    function _decodeLength(Memory.Slice item) private pure returns (uint256, uint256, ItemType) {
         uint256 itemLength = item.length();
 
         require(itemLength != 0, RLPInvalidEncoding());