// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2019-2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.8.7;

library AddressAliasHelper {
    uint160 constant offset = uint160(0x1111000000000000000000000000000000001111);

    /// @notice Utility function that converts the address in the BL that submitted a tx to
    /// the inbox to the msg.sender viewed in the SL
    /// @param blAddress the address in the BL that triggered the tx to SL
    /// @return slAddress SL address as viewed in msg.sender
    function applyBLToSLAlias(address blAddress) internal pure returns (address slAddress) {
        unchecked {
            slAddress = address(uint160(blAddress) + offset);
        }
    }

    /// @notice Utility function that converts the msg.sender viewed in the SL to the
    /// address in the BL that submitted a tx to the inbox
    /// @param slAddress SL address as viewed in msg.sender
    /// @return blAddress the address in the BL that triggered the tx to SL
    function undoBLToSLAlias(address slAddress) internal pure returns (address blAddress) {
        unchecked {
            blAddress = address(uint160(slAddress) - offset);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// SPDX-License-Identifier: MIT
pragma solidity >0.5.0 <0.9.0;

/* Library Imports */
import { Lib_NVMCodec } from "../../libraries/codec/Lib_NVMCodec.sol";

/**
 * @title IMessageQueue
 */
interface IMessageQueue {
    /**********
     * Events *
     **********/

    event TransactionEnqueued(
        address indexed _blTxOrigin,
        address indexed _target,
        uint256 _gasLimit,
        bytes _data,
        uint256 indexed _queueIndex,
        uint256 _timestamp
    );

    /********************
     * Public Functions *
     ********************/

    /**
     * Gets the queue element at a particular index.
     * @param _index Index of the queue element to access.
     * @return _element Queue element at the given index.
     */
    function getQueueElement(uint256 _index)
        external
        view
        returns (Lib_NVMCodec.QueueElement memory _element);

    /**
     * Retrieves the length of the queue, including
     * both pending and canonical transactions.
     * @return Length of the queue.
     */
    function getQueueLength() external view returns (uint40);

    /**
     * Adds a transaction to the queue.
     * @param _target Target contract to send the transaction to.
     * @param _gasLimit Gas limit for the given transaction.
     * @param _data Transaction data.
     */
    function enqueue(
        address _target,
        uint256 _gasLimit,
        bytes memory _data
    ) external;
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

/* External Imports */
import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";

/**
 * @title Lib_AddressManager
 */
contract Lib_AddressManager is Ownable {
    /**********
     * Events *
     **********/

    event AddressSet(string indexed _name, address _newAddress, address _oldAddress);

    /*************
     * Variables *
     *************/

    mapping(bytes32 => address) private addresses;

    /********************
     * Public Functions *
     ********************/

    /**
     * Changes the address associated with a particular name.
     * @param _name String name to associate an address with.
     * @param _address Address to associate with the name.
     */
    function setAddress(string memory _name, address _address) external onlyOwner {
        bytes32 nameHash = _getNameHash(_name);
        address oldAddress = addresses[nameHash];
        addresses[nameHash] = _address;

        emit AddressSet(_name, _address, oldAddress);
    }

    /**
     * Retrieves the address associated with a given name.
     * @param _name Name to retrieve an address for.
     * @return Address associated with the given name.
     */
    function getAddress(string memory _name) external view returns (address) {
        return addresses[_getNameHash(_name)];
    }

    /**********************
     * Internal Functions *
     **********************/

    /**
     * Computes the hash of a name.
     * @param _name Name to compute a hash for.
     * @return Hash of the given name.
     */
    function _getNameHash(string memory _name) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked(_name));
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

/* Library Imports */
import { Lib_AddressManager } from "./Lib_AddressManager.sol";

/**
 * @title Lib_AddressResolver
 */
abstract contract Lib_AddressResolver {
    /*************
     * Variables *
     *************/

    Lib_AddressManager public libAddressManager;

    /***************
     * Constructor *
     ***************/

    /**
     * @param _libAddressManager Address of the Lib_AddressManager.
     */
    constructor(address _libAddressManager) {
        libAddressManager = Lib_AddressManager(_libAddressManager);
    }

    /********************
     * Public Functions *
     ********************/

    /**
     * Resolves the address associated with a given name.
     * @param _name Name to resolve an address for.
     * @return Address associated with the given name.
     */
    function resolve(string memory _name) public view returns (address) {
        return libAddressManager.getAddress(_name);
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

/**
 * @title Lib_Byte32Utils
 */
library Lib_Bytes32Utils {
    /**********************
     * Internal Functions *
     **********************/

    /**
     * Converts a bytes32 value to a boolean. Anything non-zero will be converted to "true."
     * @param _in Input bytes32 value.
     * @return Bytes32 as a boolean.
     */
    function toBool(bytes32 _in) internal pure returns (bool) {
        return _in != 0;
    }

    /**
     * Converts a boolean to a bytes32 value.
     * @param _in Input boolean value.
     * @return Boolean as a bytes32.
     */
    function fromBool(bool _in) internal pure returns (bytes32) {
        return bytes32(uint256(_in ? 1 : 0));
    }

    /**
     * Converts a bytes32 value to an address. Takes the *last* 20 bytes.
     * @param _in Input bytes32 value.
     * @return Bytes32 as an address.
     */
    function toAddress(bytes32 _in) internal pure returns (address) {
        return address(uint160(uint256(_in)));
    }

    /**
     * Converts an address to a bytes32.
     * @param _in Input address value.
     * @return Address as a bytes32.
     */
    function fromAddress(address _in) internal pure returns (bytes32) {
        return bytes32(uint256(uint160(_in)));
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

/**
 * @title Lib_BytesUtils
 */
library Lib_BytesUtils {
    /**********************
     * Internal Functions *
     **********************/

    function slice(
        bytes memory _bytes,
        uint256 _start,
        uint256 _length
    ) internal pure returns (bytes memory) {
        require(_length + 31 >= _length, "slice_overflow");
        require(_start + _length >= _start, "slice_overflow");
        require(_bytes.length >= _start + _length, "slice_outOfBounds");

        bytes memory tempBytes;

        assembly {
            switch iszero(_length)
            case 0 {
                // Get a location of some free memory and store it in tempBytes as
                // Solidity does for memory variables.
                tempBytes := mload(0x40)

                // The first word of the slice result is potentially a partial
                // word read from the original array. To read it, we calculate
                // the length of that partial word and start copying that many
                // bytes into the array. The first word we copy will start with
                // data we don't care about, but the last `lengthmod` bytes will
                // land at the beginning of the contents of the new array. When
                // we're done copying, we overwrite the full first word with
                // the actual length of the slice.
                let lengthmod := and(_length, 31)

                // The multiplication in the next line is necessary
                // because when slicing multiples of 32 bytes (lengthmod == 0)
                // the following copy loop was copying the origin's length
                // and then ending prematurely not copying everything it should.
                let mc := add(add(tempBytes, lengthmod), mul(0x20, iszero(lengthmod)))
                let end := add(mc, _length)

                for {
                    // The multiplication in the next line has the same exact purpose
                    // as the one above.
                    let cc := add(add(add(_bytes, lengthmod), mul(0x20, iszero(lengthmod))), _start)
                } lt(mc, end) {
                    mc := add(mc, 0x20)
                    cc := add(cc, 0x20)
                } {
                    mstore(mc, mload(cc))
                }

                mstore(tempBytes, _length)

                //update free-memory pointer
                //allocating the array padded to 32 bytes like the compiler does now
                mstore(0x40, and(add(mc, 31), not(31)))
            }
            //if we want a zero-length slice let's just return a zero-length array
            default {
                tempBytes := mload(0x40)

                //zero out the 32 bytes slice we are about to return
                //we need to do it because Solidity does not garbage collect
                mstore(tempBytes, 0)

                mstore(0x40, add(tempBytes, 0x20))
            }
        }

        return tempBytes;
    }

    function slice(bytes memory _bytes, uint256 _start) internal pure returns (bytes memory) {
        if (_start >= _bytes.length) {
            return bytes("");
        }

        return slice(_bytes, _start, _bytes.length - _start);
    }

    function toBytes32(bytes memory _bytes) internal pure returns (bytes32) {
        if (_bytes.length < 32) {
            bytes32 ret;
            assembly {
                ret := mload(add(_bytes, 32))
            }
            return ret;
        }

        return abi.decode(_bytes, (bytes32)); // will truncate if input length > 32 bytes
    }

    function toUint256(bytes memory _bytes) internal pure returns (uint256) {
        return uint256(toBytes32(_bytes));
    }

    function toNibbles(bytes memory _bytes) internal pure returns (bytes memory) {
        bytes memory nibbles = new bytes(_bytes.length * 2);

        for (uint256 i = 0; i < _bytes.length; i++) {
            nibbles[i * 2] = _bytes[i] >> 4;
            nibbles[i * 2 + 1] = bytes1(uint8(_bytes[i]) % 16);
        }

        return nibbles;
    }

    function fromNibbles(bytes memory _bytes) internal pure returns (bytes memory) {
        bytes memory ret = new bytes(_bytes.length / 2);

        for (uint256 i = 0; i < ret.length; i++) {
            ret[i] = (_bytes[i * 2] << 4) | (_bytes[i * 2 + 1]);
        }

        return ret;
    }

    function equal(bytes memory _bytes, bytes memory _other) internal pure returns (bool) {
        return keccak256(_bytes) == keccak256(_other);
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

/* Library Imports */
import { Lib_RLPReader } from "../rlp/Lib_RLPReader.sol";
import { Lib_RLPWriter } from "../rlp/Lib_RLPWriter.sol";
import { Lib_BytesUtils } from "../utils/Lib_BytesUtils.sol";
import { Lib_Bytes32Utils } from "../utils/Lib_Bytes32Utils.sol";

/**
 * @title Lib_NVMCodec
 */
library Lib_NVMCodec {
    /*********
     * Enums *
     *********/

    enum QueueOrigin {
        SEQUENCER_QUEUE,
        BLTOSL_QUEUE
    }

    /***********
     * Structs *
     ***********/

    struct EVMAccount {
        uint256 nonce;
        uint256 balance;
        bytes32 storageRoot;
        bytes32 codeHash;
    }

    struct ChainBatchHeader {
        uint256 batchIndex;
        bytes32 batchRoot;
        uint256 batchSize;
        uint256 prevTotalElements;
        bytes extraData;
    }

    struct ChainInclusionProof {
        uint256 index;
        bytes32[] siblings;
    }

    struct Transaction {
        uint256 blTimestamp;
        uint256 blockNumber;
        uint256 slTimestamp;
        QueueOrigin blQueueOrigin;
        bytes data;
    }

    struct TransactionChainElement {
        bool isSequenced;
        uint256 queueIndex; // QUEUED TX ONLY
        uint256 timestamp; // SEQUENCER TX ONLY
        uint256 blockNumber; // SEQUENCER TX ONLY
        bytes txData; // SEQUENCER TX ONLY
    }

    struct QueueElement {
        bytes32 transactionHash;
        uint40 timestamp;
        uint40 blockNumber;
    }

    struct Receipt {
        uint256 index;
        bytes32 stateRoot;
        bytes32 operatorHash;
        bytes operatorSignature;
    }

    /**********************
     * Internal Functions *
     **********************/

    /**
     * Encodes a standard NVM transaction.
     * @param _transaction NVM transaction to encode.
     * @return Encoded transaction bytes.
     */
    function encodeTransaction(Transaction memory _transaction)
        internal
        pure
        returns (bytes memory)
    {
        return
            abi.encodePacked(
                _transaction.blTimestamp,
                _transaction.blockNumber,
                _transaction.slTimestamp,
                _transaction.blQueueOrigin,
                _transaction.data
            );
    }

    /**
     * Hashes a standard NVM transaction.
     * @param _transaction NVM transaction to encode.
     * @return Hashed transaction
     */
    function hashTransaction(Transaction memory _transaction) internal pure returns (bytes32) {
        return keccak256(encodeTransaction(_transaction));
    }

    /**
     * @notice Decodes an RLP-encoded account state into a useful struct.
     * @param _encoded RLP-encoded account state.
     * @return Account state struct.
     */
    function decodeEVMAccount(bytes memory _encoded) internal pure returns (EVMAccount memory) {
        Lib_RLPReader.RLPItem[] memory accountState = Lib_RLPReader.readList(_encoded);

        return
            EVMAccount({
                nonce: Lib_RLPReader.readUint256(accountState[0]),
                balance: Lib_RLPReader.readUint256(accountState[1]),
                storageRoot: Lib_RLPReader.readBytes32(accountState[2]),
                codeHash: Lib_RLPReader.readBytes32(accountState[3])
            });
    }

    /**
     * Calculates a hash for a given batch header.
     * @param _batchHeader Header to hash.
     * @return Hash of the header.
     */
    function hashBatchHeader(Lib_NVMCodec.ChainBatchHeader memory _batchHeader)
        internal
        pure
        returns (bytes32)
    {
        return
            keccak256(
                abi.encode(
                    _batchHeader.batchRoot,
                    _batchHeader.batchSize,
                    _batchHeader.prevTotalElements,
                    _batchHeader.extraData
                )
            );
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

/**
 * @title Lib_RLPReader
 * @dev Adapted from "RLPReader" by Hamdi Allam (hamdi.allam97@gmail.com).
 */
library Lib_RLPReader {
    /*************
     * Constants *
     *************/

    uint256 internal constant MAX_LIST_LENGTH = 32;

    /*********
     * Enums *
     *********/

    enum RLPItemType {
        DATA_ITEM,
        LIST_ITEM
    }

    /***********
     * Structs *
     ***********/

    struct RLPItem {
        uint256 length;
        uint256 ptr;
    }

    /**********************
     * Internal Functions *
     **********************/

    /**
     * Converts bytes to a reference to memory position and length.
     * @param _in Input bytes to convert.
     * @return Output memory reference.
     */
    function toRLPItem(bytes memory _in) internal pure returns (RLPItem memory) {
        uint256 ptr;
        assembly {
            ptr := add(_in, 32)
        }

        return RLPItem({ length: _in.length, ptr: ptr });
    }

    /**
     * Reads an RLP list value into a list of RLP items.
     * @param _in RLP list value.
     * @return Decoded RLP list items.
     */
    function readList(RLPItem memory _in) internal pure returns (RLPItem[] memory) {
        (uint256 listOffset, , RLPItemType itemType) = _decodeLength(_in);

        require(itemType == RLPItemType.LIST_ITEM, "Invalid RLP list value.");

        // Solidity in-memory arrays can't be increased in size, but *can* be decreased in size by
        // writing to the length. Since we can't know the number of RLP items without looping over
        // the entire input, we'd have to loop twice to accurately size this array. It's easier to
        // simply set a reasonable maximum list length and decrease the size before we finish.
        RLPItem[] memory out = new RLPItem[](MAX_LIST_LENGTH);

        uint256 itemCount = 0;
        uint256 offset = listOffset;
        while (offset < _in.length) {
            require(itemCount < MAX_LIST_LENGTH, "Provided RLP list exceeds max list length.");

            (uint256 itemOffset, uint256 itemLength, ) = _decodeLength(
                RLPItem({ length: _in.length - offset, ptr: _in.ptr + offset })
            );

            out[itemCount] = RLPItem({ length: itemLength + itemOffset, ptr: _in.ptr + offset });

            itemCount += 1;
            offset += itemOffset + itemLength;
        }

        // Decrease the array size to match the actual item count.
        assembly {
            mstore(out, itemCount)
        }

        return out;
    }

    /**
     * Reads an RLP list value into a list of RLP items.
     * @param _in RLP list value.
     * @return Decoded RLP list items.
     */
    function readList(bytes memory _in) internal pure returns (RLPItem[] memory) {
        return readList(toRLPItem(_in));
    }

    /**
     * Reads an RLP bytes value into bytes.
     * @param _in RLP bytes value.
     * @return Decoded bytes.
     */
    function readBytes(RLPItem memory _in) internal pure returns (bytes memory) {
        (uint256 itemOffset, uint256 itemLength, RLPItemType itemType) = _decodeLength(_in);

        require(itemType == RLPItemType.DATA_ITEM, "Invalid RLP bytes value.");

        return _copy(_in.ptr, itemOffset, itemLength);
    }

    /**
     * Reads an RLP bytes value into bytes.
     * @param _in RLP bytes value.
     * @return Decoded bytes.
     */
    function readBytes(bytes memory _in) internal pure returns (bytes memory) {
        return readBytes(toRLPItem(_in));
    }

    /**
     * Reads an RLP string value into a string.
     * @param _in RLP string value.
     * @return Decoded string.
     */
    function readString(RLPItem memory _in) internal pure returns (string memory) {
        return string(readBytes(_in));
    }

    /**
     * Reads an RLP string value into a string.
     * @param _in RLP string value.
     * @return Decoded string.
     */
    function readString(bytes memory _in) internal pure returns (string memory) {
        return readString(toRLPItem(_in));
    }

    /**
     * Reads an RLP bytes32 value into a bytes32.
     * @param _in RLP bytes32 value.
     * @return Decoded bytes32.
     */
    function readBytes32(RLPItem memory _in) internal pure returns (bytes32) {
        require(_in.length <= 33, "Invalid RLP bytes32 value.");

        (uint256 itemOffset, uint256 itemLength, RLPItemType itemType) = _decodeLength(_in);

        require(itemType == RLPItemType.DATA_ITEM, "Invalid RLP bytes32 value.");

        uint256 ptr = _in.ptr + itemOffset;
        bytes32 out;
        assembly {
            out := mload(ptr)

            // Shift the bytes over to match the item size.
            if lt(itemLength, 32) {
                out := div(out, exp(256, sub(32, itemLength)))
            }
        }

        return out;
    }

    /**
     * Reads an RLP bytes32 value into a bytes32.
     * @param _in RLP bytes32 value.
     * @return Decoded bytes32.
     */
    function readBytes32(bytes memory _in) internal pure returns (bytes32) {
        return readBytes32(toRLPItem(_in));
    }

    /**
     * Reads an RLP uint256 value into a uint256.
     * @param _in RLP uint256 value.
     * @return Decoded uint256.
     */
    function readUint256(RLPItem memory _in) internal pure returns (uint256) {
        return uint256(readBytes32(_in));
    }

    /**
     * Reads an RLP uint256 value into a uint256.
     * @param _in RLP uint256 value.
     * @return Decoded uint256.
     */
    function readUint256(bytes memory _in) internal pure returns (uint256) {
        return readUint256(toRLPItem(_in));
    }

    /**
     * Reads an RLP bool value into a bool.
     * @param _in RLP bool value.
     * @return Decoded bool.
     */
    function readBool(RLPItem memory _in) internal pure returns (bool) {
        require(_in.length == 1, "Invalid RLP boolean value.");

        uint256 ptr = _in.ptr;
        uint256 out;
        assembly {
            out := byte(0, mload(ptr))
        }

        require(out == 0 || out == 1, "Lib_RLPReader: Invalid RLP boolean value, must be 0 or 1");

        return out != 0;
    }

    /**
     * Reads an RLP bool value into a bool.
     * @param _in RLP bool value.
     * @return Decoded bool.
     */
    function readBool(bytes memory _in) internal pure returns (bool) {
        return readBool(toRLPItem(_in));
    }

    /**
     * Reads an RLP address value into a address.
     * @param _in RLP address value.
     * @return Decoded address.
     */
    function readAddress(RLPItem memory _in) internal pure returns (address) {
        if (_in.length == 1) {
            return address(0);
        }

        require(_in.length == 21, "Invalid RLP address value.");

        return address(uint160(readUint256(_in)));
    }

    /**
     * Reads an RLP address value into a address.
     * @param _in RLP address value.
     * @return Decoded address.
     */
    function readAddress(bytes memory _in) internal pure returns (address) {
        return readAddress(toRLPItem(_in));
    }

    /**
     * Reads the raw bytes of an RLP item.
     * @param _in RLP item to read.
     * @return Raw RLP bytes.
     */
    function readRawBytes(RLPItem memory _in) internal pure returns (bytes memory) {
        return _copy(_in);
    }

    /*********************
     * Private Functions *
     *********************/

    /**
     * Decodes the length of an RLP item.
     * @param _in RLP item to decode.
     * @return Offset of the encoded data.
     * @return Length of the encoded data.
     * @return RLP item type (LIST_ITEM or DATA_ITEM).
     */
    function _decodeLength(RLPItem memory _in)
        private
        pure
        returns (
            uint256,
            uint256,
            RLPItemType
        )
    {
        require(_in.length > 0, "RLP item cannot be null.");

        uint256 ptr = _in.ptr;
        uint256 prefix;
        assembly {
            prefix := byte(0, mload(ptr))
        }

        if (prefix <= 0x7f) {
            // Single byte.

            return (0, 1, RLPItemType.DATA_ITEM);
        } else if (prefix <= 0xb7) {
            // Short string.

            // slither-disable-next-line variable-scope
            uint256 strLen = prefix - 0x80;

            require(_in.length > strLen, "Invalid RLP short string.");

            return (1, strLen, RLPItemType.DATA_ITEM);
        } else if (prefix <= 0xbf) {
            // Long string.
            uint256 lenOfStrLen = prefix - 0xb7;

            require(_in.length > lenOfStrLen, "Invalid RLP long string length.");

            uint256 strLen;
            assembly {
                // Pick out the string length.
                strLen := div(mload(add(ptr, 1)), exp(256, sub(32, lenOfStrLen)))
            }

            require(_in.length > lenOfStrLen + strLen, "Invalid RLP long string.");

            return (1 + lenOfStrLen, strLen, RLPItemType.DATA_ITEM);
        } else if (prefix <= 0xf7) {
            // Short list.
            // slither-disable-next-line variable-scope
            uint256 listLen = prefix - 0xc0;

            require(_in.length > listLen, "Invalid RLP short list.");

            return (1, listLen, RLPItemType.LIST_ITEM);
        } else {
            // Long list.
            uint256 lenOfListLen = prefix - 0xf7;

            require(_in.length > lenOfListLen, "Invalid RLP long list length.");

            uint256 listLen;
            assembly {
                // Pick out the list length.
                listLen := div(mload(add(ptr, 1)), exp(256, sub(32, lenOfListLen)))
            }

            require(_in.length > lenOfListLen + listLen, "Invalid RLP long list.");

            return (1 + lenOfListLen, listLen, RLPItemType.LIST_ITEM);
        }
    }

    /**
     * Copies the bytes from a memory location.
     * @param _src Pointer to the location to read from.
     * @param _offset Offset to start reading from.
     * @param _length Number of bytes to read.
     * @return Copied bytes.
     */
    function _copy(
        uint256 _src,
        uint256 _offset,
        uint256 _length
    ) private pure returns (bytes memory) {
        bytes memory out = new bytes(_length);
        if (out.length == 0) {
            return out;
        }

        uint256 src = _src + _offset;
        uint256 dest;
        assembly {
            dest := add(out, 32)
        }

        // Copy over as many complete words as we can.
        for (uint256 i = 0; i < _length / 32; i++) {
            assembly {
                mstore(dest, mload(src))
            }

            src += 32;
            dest += 32;
        }

        // Pick out the remaining bytes.
        uint256 mask;
        unchecked {
            mask = 256**(32 - (_length % 32)) - 1;
        }

        assembly {
            mstore(dest, or(and(mload(src), not(mask)), and(mload(dest), mask)))
        }
        return out;
    }

    /**
     * Copies an RLP item into bytes.
     * @param _in RLP item to copy.
     * @return Copied bytes.
     */
    function _copy(RLPItem memory _in) private pure returns (bytes memory) {
        return _copy(_in.ptr, 0, _in.length);
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

/**
 * @title Lib_RLPWriter
 * @author Bakaoh (with modifications)
 */
library Lib_RLPWriter {
    /**********************
     * Internal Functions *
     **********************/

    /**
     * RLP encodes a byte string.
     * @param _in The byte string to encode.
     * @return The RLP encoded string in bytes.
     */
    function writeBytes(bytes memory _in) internal pure returns (bytes memory) {
        bytes memory encoded;

        if (_in.length == 1 && uint8(_in[0]) < 128) {
            encoded = _in;
        } else {
            encoded = abi.encodePacked(_writeLength(_in.length, 128), _in);
        }

        return encoded;
    }

    /**
     * RLP encodes a list of RLP encoded byte byte strings.
     * @param _in The list of RLP encoded byte strings.
     * @return The RLP encoded list of items in bytes.
     */
    function writeList(bytes[] memory _in) internal pure returns (bytes memory) {
        bytes memory list = _flatten(_in);
        return abi.encodePacked(_writeLength(list.length, 192), list);
    }

    /**
     * RLP encodes a string.
     * @param _in The string to encode.
     * @return The RLP encoded string in bytes.
     */
    function writeString(string memory _in) internal pure returns (bytes memory) {
        return writeBytes(bytes(_in));
    }

    /**
     * RLP encodes an address.
     * @param _in The address to encode.
     * @return The RLP encoded address in bytes.
     */
    function writeAddress(address _in) internal pure returns (bytes memory) {
        return writeBytes(abi.encodePacked(_in));
    }

    /**
     * RLP encodes a uint.
     * @param _in The uint256 to encode.
     * @return The RLP encoded uint256 in bytes.
     */
    function writeUint(uint256 _in) internal pure returns (bytes memory) {
        return writeBytes(_toBinary(_in));
    }

    /**
     * RLP encodes a bool.
     * @param _in The bool to encode.
     * @return The RLP encoded bool in bytes.
     */
    function writeBool(bool _in) internal pure returns (bytes memory) {
        bytes memory encoded = new bytes(1);
        encoded[0] = (_in ? bytes1(0x01) : bytes1(0x80));
        return encoded;
    }

    /*********************
     * Private Functions *
     *********************/

    /**
     * Encode the first byte, followed by the `len` in binary form if `length` is more than 55.
     * @param _len The length of the string or the payload.
     * @param _offset 128 if item is string, 192 if item is list.
     * @return RLP encoded bytes.
     */
    function _writeLength(uint256 _len, uint256 _offset) private pure returns (bytes memory) {
        bytes memory encoded;

        if (_len < 56) {
            encoded = new bytes(1);
            encoded[0] = bytes1(uint8(_len) + uint8(_offset));
        } else {
            uint256 lenLen;
            uint256 i = 1;
            while (_len / i != 0) {
                lenLen++;
                i *= 256;
            }

            encoded = new bytes(lenLen + 1);
            encoded[0] = bytes1(uint8(lenLen) + uint8(_offset) + 55);
            for (i = 1; i <= lenLen; i++) {
                encoded[i] = bytes1(uint8((_len / (256**(lenLen - i))) % 256));
            }
        }

        return encoded;
    }

    /**
     * Encode integer in big endian binary form with no leading zeroes.
     * @notice TODO: This should be optimized with assembly to save gas costs.
     * @param _x The integer to encode.
     * @return RLP encoded bytes.
     */
    function _toBinary(uint256 _x) private pure returns (bytes memory) {
        bytes memory b = abi.encodePacked(_x);

        uint256 i = 0;
        for (; i < 32; i++) {
            if (b[i] != 0) {
                break;
            }
        }

        bytes memory res = new bytes(32 - i);
        for (uint256 j = 0; j < res.length; j++) {
            res[j] = b[i++];
        }

        return res;
    }

    /**
     * Copies a piece of memory to another location.
     * @notice From: https://github.com/Arachnid/solidity-stringutils/blob/master/src/strings.sol.
     * @param _dest Destination location.
     * @param _src Source location.
     * @param _len Length of memory to copy.
     */
    function _memcpy(
        uint256 _dest,
        uint256 _src,
        uint256 _len
    ) private pure {
        uint256 dest = _dest;
        uint256 src = _src;
        uint256 len = _len;

        for (; len >= 32; len -= 32) {
            assembly {
                mstore(dest, mload(src))
            }
            dest += 32;
            src += 32;
        }

        uint256 mask;
        unchecked {
            mask = 256**(32 - len) - 1;
        }
        assembly {
            let srcpart := and(mload(src), not(mask))
            let destpart := and(mload(dest), mask)
            mstore(dest, or(destpart, srcpart))
        }
    }

    /**
     * Flattens a list of byte strings into one byte string.
     * @notice From: https://github.com/sammayo/solidity-rlp-encoder/blob/master/RLPEncode.sol.
     * @param _list List of byte strings to flatten.
     * @return The flattened byte string.
     */
    function _flatten(bytes[] memory _list) private pure returns (bytes memory) {
        if (_list.length == 0) {
            return new bytes(0);
        }

        uint256 len;
        uint256 i = 0;
        for (; i < _list.length; i++) {
            len += _list[i].length;
        }

        bytes memory flattened = new bytes(len);
        uint256 flattenedPtr;
        assembly {
            flattenedPtr := add(flattened, 0x20)
        }

        for (i = 0; i < _list.length; i++) {
            bytes memory item = _list[i];

            uint256 listPtr;
            assembly {
                listPtr := add(item, 0x20)
            }

            _memcpy(flattenedPtr, listPtr, item.length);
            flattenedPtr += _list[i].length;
        }

        return flattened;
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

/* Library Imports */
import { AddressAliasHelper } from "../../standards/AddressAliasHelper.sol";
import { Lib_NVMCodec } from "../../libraries/codec/Lib_NVMCodec.sol";
import { Lib_AddressResolver } from "../../libraries/resolver/Lib_AddressResolver.sol";

/* Interface Imports */
import { IMessageQueue } from "./IMessageQueue.sol";
import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";

/**
 * @title MessageQueue
 * @dev TODO
 *
 */
contract MessageQueue is IMessageQueue, Lib_AddressResolver, Ownable {
    /*************
     * Constants *
     *************/

    // SL tx gas-related
    uint256 public constant MIN_ROLLUP_TX_GAS = 100000;
    uint256 public constant MAX_ROLLUP_TX_SIZE = 50000;
    uint256 public constant SL_GAS_DISCOUNT_DIVISOR = 32;

    /*************
     * Variables *
     *************/

    uint256 public maxTransactionGasLimit;
    bool public limitedEnqueueEnabled;
    mapping(address => bool) public enqueuers;

    /***************
     * Queue State *
     ***************/
    Lib_NVMCodec.QueueElement[] queueElements;

    /***************
     * Constructor *
     ***************/

    constructor(address _libAddressManager, uint256 _maxTransactionGasLimit)
        Lib_AddressResolver(_libAddressManager)
    {
        maxTransactionGasLimit = _maxTransactionGasLimit;
    }

    modifier onlyEnqueuer() {
        if (limitedEnqueueEnabled) {
            require(enqueuers[msg.sender], "Account is not an enabled enqueuer");
        }
        _;
    }

    /********************
     * Public Functions *
     ********************/

    /**
     * Gets the queue element at a particular index.
     * @param _index Index of the queue element to access.
     * @return _element Queue element at the given index.
     */
    function getQueueElement(uint256 _index)
        public
        view
        returns (Lib_NVMCodec.QueueElement memory _element)
    {
        return queueElements[_index];
    }

    /**
     * Retrieves the length of the queue, including
     * both pending and canonical transactions.
     * @return Length of the queue.
     */
    function getQueueLength() public view returns (uint40) {
        return uint40(queueElements.length);
    }

    /**
     * Adds a transaction to the queue.
     * @param _target Target SL contract to send the transaction to.
     * @param _gasLimit Gas limit for the enqueued SL transaction.
     * @param _data Transaction data.
     */
    function enqueue(
        address _target,
        uint256 _gasLimit,
        bytes memory _data
    ) external onlyEnqueuer {
        require(
            _data.length <= MAX_ROLLUP_TX_SIZE,
            "Transaction data size exceeds maximum for rollup transaction."
        );

        require(
            _gasLimit <= maxTransactionGasLimit,
            "Transaction gas limit exceeds maximum for rollup transaction."
        );

        require(_gasLimit >= MIN_ROLLUP_TX_GAS, "Transaction gas limit too low to enqueue.");

        // Apply an aliasing unless msg.sender == tx.origin. This prevents an attack in which a
        // contract on BL has the same address as a contract on SL but doesn't have the same code.
        // We can safely ignore this for EOAs because they're guaranteed to have the same "code"
        // (i.e. no code at all). This also makes it possible for users to interact with contracts
        // on SL even when the Sequencer is down.
        address sender;
        if (msg.sender == tx.origin) {
            sender = msg.sender;
        } else {
            sender = AddressAliasHelper.applyBLToSLAlias(msg.sender);
        }

        bytes32 transactionHash = keccak256(abi.encode(sender, _target, _gasLimit, _data));

        queueElements.push(
            Lib_NVMCodec.QueueElement({
                transactionHash: transactionHash,
                timestamp: uint40(block.timestamp),
                blockNumber: uint40(block.number)
            })
        );
        uint256 queueIndex = queueElements.length - 1;
        emit TransactionEnqueued(sender, _target, _gasLimit, _data, queueIndex, block.timestamp);
    }

    function toggleLimitedEnqueue() external onlyOwner returns (bool) {
        limitedEnqueueEnabled = !limitedEnqueueEnabled;
        return limitedEnqueueEnabled;
    }

    function addEnqueuer(address _address) external onlyOwner {
        enqueuers[_address] = true;
    }

    function removeEnqueuer(address _address) external onlyOwner {
        enqueuers[_address] = false;
    }

    function isEnqueuer(address _address) public view returns (bool result) {
        result = enqueuers[_address];
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

{
  "compilationTarget": {
    "contracts/BL/rollup/MessageQueue.sol": "MessageQueue"
  },
  "evmVersion": "paris",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs",
    "useLiteralContent": true
  },
  "optimizer": {
    "enabled": true,
    "runs": 10000
  },
  "remappings": []
}