A problem in my balanceOfBatch function in ERC1155 contract

this is my ERC1155 contract:

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.2;

import "@openzeppelin/contracts/token/ERC1155/IERC1155.sol";
import "@openzeppelin/contracts/token/ERC1155/IERC1155Receiver.sol";
import "@openzeppelin/contracts/token/ERC1155/extensions/IERC1155MetadataURI.sol";
import "@openzeppelin/contracts/utils/Context.sol";
import "@openzeppelin/contracts/utils/introspection/ERC165.sol";
import "@openzeppelin/contracts/utils/Arrays.sol";
import "@openzeppelin/contracts/interfaces/draft-IERC6093.sol";

/**
 * @dev Implementation of the basic standard multi-token.
 * See https://eips.ethereum.org/EIPS/eip-1155
 * Originally based on code by Enjin: https://github.com/enjin/erc-1155
 */
abstract contract ERC1155 is Context, ERC165, IERC1155, IERC1155MetadataURI, IERC1155Errors {
    using Arrays for uint256[];
    using Arrays for address[];

    // Mapping from token ID to account balances
    mapping(uint256 => mapping(address => uint256)) private _balances;

    // Mapping from account to operator approvals
    mapping(address => mapping(address => bool)) private _operatorApprovals;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Used as the URI for all token types by relying on ID substitution, e.g. https://token-cdn-domain/{id}.json
    string private _uri;

    /**
     * @dev See {_setURI}.
     */
    constructor(string memory uri_) {
        _setURI(uri_);
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC1155).interfaceId ||
            interfaceId == type(IERC1155MetadataURI).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC1155MetadataURI-uri}.
     *
     * This implementation returns the same URI for *all* token types. It relies
     * on the token type ID substitution mechanism
     * https://eips.ethereum.org/EIPS/eip-1155#metadata[defined in the EIP].
     *
     * Clients calling this function must replace the `\{id\}` substring with the
     * actual token type ID.
     */
    function uri(uint256 /* id */) public view virtual returns (string memory) {
        return _uri;
    }

    /**
     * @dev See {IERC1155-balanceOf}.
     */
    function balanceOf(address account, uint256 id) public view virtual returns (uint256) {
        return _balances[id][account];
    }

    /**
     * @dev See {IERC1155-balanceOfBatch}.
     *
     * Requirements:
     *
     * - `accounts` and `ids` must have the same length.
     */
    function balanceOfBatch(
        address[] memory accounts,
        uint256[] memory ids
    ) public view virtual returns (uint256[] memory) {
        if (accounts.length != ids.length) {
            revert ERC1155InvalidArrayLength(ids.length, accounts.length);
        }

        uint256[] memory batchBalances = new uint256[](accounts.length);

        for (uint256 i = 0; i < accounts.length; ++i) {
            batchBalances[i] = balanceOf(accounts.unsafeMemoryAccess(i), ids.unsafeMemoryAccess(i));
        }

        return batchBalances;
    }

    /**
     * @dev See {IERC1155-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual {
        _setApprovalForAll(_msgSender(), operator, approved);
    }

    /**
     * @dev See {IERC1155-isApprovedForAll}.
     */
    function isApprovedForAll(address account, address operator) public view virtual returns (bool) {
        return _operatorApprovals[account][operator];
    }

    /**
     * @dev See {IERC1155-safeTransferFrom}.
     */
    function safeTransferFrom(address from, address to, uint256 id, uint256 value, bytes memory data) public virtual {
        address sender = _msgSender();
        if (from != sender && !isApprovedForAll(from, sender)) {
            revert ERC1155MissingApprovalForAll(sender, from);
        }
        _safeTransferFrom(from, to, id, value, data);
    }

    /**
     * @dev See {IERC1155-safeBatchTransferFrom}.
     */
    function safeBatchTransferFrom(
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory values,
        bytes memory data
    ) public virtual {
        address sender = _msgSender();
        if (from != sender && !isApprovedForAll(from, sender)) {
            revert ERC1155MissingApprovalForAll(sender, from);
        }
        _safeBatchTransferFrom(from, to, ids, values, data);
    }

    /**
     * @dev Transfers a `value` amount of tokens of type `id` from `from` to `to`. Will mint (or burn) if `from` (or `to`) is the zero address.
     *
     * Emits a {TransferSingle} event if the arrays contain one element, and {TransferBatch} otherwise.
     *
     * Requirements:
     *
     * - If `to` refers to a smart contract, it must implement either {IERC1155Receiver-onERC1155Received}
     *   or {IERC1155Receiver-onERC1155BatchReceived} and return the acceptance magic value.
     * - `ids` and `values` must have the same length.
     *
     * NOTE: The ERC-1155 acceptance check is not performed in this function. See {_updateWithAcceptanceCheck} instead.
     */
    function _update(address from, address to, uint256[] memory ids, uint256[] memory values) internal virtual {
        if (ids.length != values.length) {
            revert ERC1155InvalidArrayLength(ids.length, values.length);
        }

        address operator = _msgSender();

        for (uint256 i = 0; i < ids.length; ++i) {
            uint256 id = ids.unsafeMemoryAccess(i);
            uint256 value = values.unsafeMemoryAccess(i);

            if (from != address(0)) {
                uint256 fromBalance = _balances[id][from];
                if (fromBalance < value) {
                    revert ERC1155InsufficientBalance(from, fromBalance, value, id);
                }
                unchecked {
                    // Overflow not possible: value <= fromBalance
                    _balances[id][from] = fromBalance - value;
                }
            }

            if (to != address(0)) {
                _balances[id][to] += value;
            }
        }

        if (ids.length == 1) {
            uint256 id = ids.unsafeMemoryAccess(0);
            uint256 value = values.unsafeMemoryAccess(0);
            emit TransferSingle(operator, from, to, id, value);
        } else {
            emit TransferBatch(operator, from, to, ids, values);
        }
    }

    /**
     * @dev Version of {_update} that performs the token acceptance check by calling {IERC1155Receiver-onERC1155Received}
     * or {IERC1155Receiver-onERC1155BatchReceived} on the receiver address if it contains code (eg. is a smart contract
     * at the moment of execution).
     *
     * IMPORTANT: Overriding this function is discouraged because it poses a reentrancy risk from the receiver. So any
     * update to the contract state after this function would break the check-effect-interaction pattern. Consider
     * overriding {_update} instead.
     */
    function _updateWithAcceptanceCheck(
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory values,
        bytes memory data
    ) internal virtual {
        _update(from, to, ids, values);
        if (to != address(0)) {
            address operator = _msgSender();
            if (ids.length == 1) {
                uint256 id = ids.unsafeMemoryAccess(0);
                uint256 value = values.unsafeMemoryAccess(0);
                _doSafeTransferAcceptanceCheck(operator, from, to, id, value, data);
            } else {
                _doSafeBatchTransferAcceptanceCheck(operator, from, to, ids, values, data);
            }
        }
    }

    /**
     * @dev Transfers a `value` tokens of token type `id` from `from` to `to`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `from` must have a balance of tokens of type `id` of at least `value` amount.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function _safeTransferFrom(address from, address to, uint256 id, uint256 value, bytes memory data) internal {
        if (to == address(0)) {
            revert ERC1155InvalidReceiver(address(0));
        }
        if (from == address(0)) {
            revert ERC1155InvalidSender(address(0));
        }
        (uint256[] memory ids, uint256[] memory values) = _asSingletonArrays(id, value);
        _updateWithAcceptanceCheck(from, to, ids, values, data);
    }

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {_safeTransferFrom}.
     *
     * Emits a {TransferBatch} event.
     *
     * Requirements:
     *
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     * - `ids` and `values` must have the same length.
     */
    function _safeBatchTransferFrom(
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory values,
        bytes memory data
    ) internal {
        if (to == address(0)) {
            revert ERC1155InvalidReceiver(address(0));
        }
        if (from == address(0)) {
            revert ERC1155InvalidSender(address(0));
        }
        _updateWithAcceptanceCheck(from, to, ids, values, data);
    }

    /**
     * @dev Sets a new URI for all token types, by relying on the token type ID
     * substitution mechanism
     * https://eips.ethereum.org/EIPS/eip-1155#metadata[defined in the EIP].
     *
     * By this mechanism, any occurrence of the `\{id\}` substring in either the
     * URI or any of the values in the JSON file at said URI will be replaced by
     * clients with the token type ID.
     *
     * For example, the `https://token-cdn-domain/\{id\}.json` URI would be
     * interpreted by clients as
     * `https://token-cdn-domain/000000000000000000000000000000000000000000000000000000000004cce0.json`
     * for token type ID 0x4cce0.
     *
     * See {uri}.
     *
     * Because these URIs cannot be meaningfully represented by the {URI} event,
     * this function emits no events.
     */
    function _setURI(string memory newuri) internal virtual {
        _uri = newuri;
    }

    /**
     * @dev Creates a `value` amount of tokens of type `id`, and assigns them to `to`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function _mint(address to, uint256 id, uint256 value, bytes memory data) internal {
        if (to == address(0)) {
            revert ERC1155InvalidReceiver(address(0));
        }
        (uint256[] memory ids, uint256[] memory values) = _asSingletonArrays(id, value);
        _updateWithAcceptanceCheck(address(0), to, ids, values, data);
    }

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {_mint}.
     *
     * Emits a {TransferBatch} event.
     *
     * Requirements:
     *
     * - `ids` and `values` must have the same length.
     * - `to` cannot be the zero address.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function _mintBatch(address to, uint256[] memory ids, uint256[] memory values, bytes memory data) internal {
        if (to == address(0)) {
            revert ERC1155InvalidReceiver(address(0));
        }
        _updateWithAcceptanceCheck(address(0), to, ids, values, data);
    }

    /**
     * @dev Destroys a `value` amount of tokens of type `id` from `from`
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `from` must have at least `value` amount of tokens of type `id`.
     */
    function _burn(address from, uint256 id, uint256 value) internal {
        if (from == address(0)) {
            revert ERC1155InvalidSender(address(0));
        }
        (uint256[] memory ids, uint256[] memory values) = _asSingletonArrays(id, value);
        _updateWithAcceptanceCheck(from, address(0), ids, values, "");
    }

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {_burn}.
     *
     * Emits a {TransferBatch} event.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `from` must have at least `value` amount of tokens of type `id`.
     * - `ids` and `values` must have the same length.
     */
    function _burnBatch(address from, uint256[] memory ids, uint256[] memory values) internal {
        if (from == address(0)) {
            revert ERC1155InvalidSender(address(0));
        }
        _updateWithAcceptanceCheck(from, address(0), ids, values, "");
    }

    /**
     * @dev Approve `operator` to operate on all of `owner` tokens
     *
     * Emits an {ApprovalForAll} event.
     *
     * Requirements:
     *
     * - `operator` cannot be the zero address.
     */
    function _setApprovalForAll(address owner, address operator, bool approved) internal virtual {
        if (operator == address(0)) {
            revert ERC1155InvalidOperator(address(0));
        }
        _operatorApprovals[owner][operator] = approved;
        emit ApprovalForAll(owner, operator, approved);
    }

    /**
     * @dev Performs an acceptance check by calling {IERC1155-onERC1155Received} on the `to` address
     * if it contains code at the moment of execution.
     */
    function _doSafeTransferAcceptanceCheck(
        address operator,
        address from,
        address to,
        uint256 id,
        uint256 value,
        bytes memory data
    ) private {
        if (to.code.length > 0) {
            try IERC1155Receiver(to).onERC1155Received(operator, from, id, value, data) returns (bytes4 response) {
                if (response != IERC1155Receiver.onERC1155Received.selector) {
                    // Tokens rejected
                    revert ERC1155InvalidReceiver(to);
                }
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    // non-ERC1155Receiver implementer
                    revert ERC1155InvalidReceiver(to);
                } else {
                    /// @solidity memory-safe-assembly
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        }
    }

    /**
     * @dev Performs a batch acceptance check by calling {IERC1155-onERC1155BatchReceived} on the `to` address
     * if it contains code at the moment of execution.
     */
    function _doSafeBatchTransferAcceptanceCheck(
        address operator,
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory values,
        bytes memory data
    ) private {
        if (to.code.length > 0) {
            try IERC1155Receiver(to).onERC1155BatchReceived(operator, from, ids, values, data) returns (
                bytes4 response
            ) {
                if (response != IERC1155Receiver.onERC1155BatchReceived.selector) {
                    // Tokens rejected
                    revert ERC1155InvalidReceiver(to);
                }
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    // non-ERC1155Receiver implementer
                    revert ERC1155InvalidReceiver(to);
                } else {
                    /// @solidity memory-safe-assembly
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        }
    }

    /**
     * @dev Creates an array in memory with only one value for each of the elements provided.
     */
    function _asSingletonArrays(
        uint256 element1,
        uint256 element2
    ) private pure returns (uint256[] memory array1, uint256[] memory array2) {
        /// @solidity memory-safe-assembly
        assembly {
            // Load the free memory pointer
            array1 := mload(0x40)
            // Set array length to 1
            mstore(array1, 1)
            // Store the single element at the next word after the length (where content starts)
            mstore(add(array1, 0x20), element1)

            // Repeat for next array locating it right after the first array
            array2 := add(array1, 0x40)
            mstore(array2, 1)
            mstore(add(array2, 0x20), element2)

            // Update the free memory pointer by pointing after the second array
            mstore(0x40, add(array2, 0x40))
        }
    }
}

it say there is a problem in my balanceOfBatch function.
on line:

batchBalances[i] = balanceOf(accounts.unsafeMemoryAccess(i), ids.unsafeMemoryAccess(i));

Its error is as follows:

Member "unsafeMemoryAccess" not found or not visible after argument-dependent lookup in address[] memory.

what's the solution?

Hey @erfan5416,

Can you confirm what environment are you using? I suspect it may be a version mismatch between contract imports if you're using Remix since it caches preloaded versions.

I use hardhat for this contract.

These two functions are available on openzeppelin master branch:

/**
 * @dev Access an array in an "unsafe" way. Skips solidity "index-out-of-range" check.
 *
 * WARNING: Only use if you are certain `pos` is lower than the array length.
 */
function unsafeMemoryAccess(uint256[] memory arr, uint256 pos) internal pure returns (uint256 res) {
    assembly {
        res := mload(add(add(arr, 0x20), mul(pos, 0x20)))
    }
}

/**
 * @dev Access an array in an "unsafe" way. Skips solidity "index-out-of-range" check.
 *
 * WARNING: Only use if you are certain `pos` is lower than the array length.
 */
function unsafeMemoryAccess(address[] memory arr, uint256 pos) internal pure returns (address res) {
    assembly {
        res := mload(add(add(arr, 0x20), mul(pos, 0x20)))
    }
}

However, the source code of the latest version (v4.9.2) doesn't seem to include them for some reason.

It looks like these two functions were pushed to the master branch after that version had been released.

So you can either implement them yourself, or wait for OZ to release them as part of an official version.

1 Like

My bad, I forgot to check out if that piece of code was already released, and will be for 5.0. I'm marking @barakman's answer as a solution.

Just remember we haven't yet released because we're going through a security review process so things may still change before the Release Candidate.

Also, curious to know, how did you find this function @erfan5416? If you took a look to master thinking that's our latest released version I think we might reconsider keeping the latest changes in master.