first commit

.gitignore

@@ -0,0 +1,2 @@
+/node_modules
+.DS_Store

package.json

@@ -0,0 +1,10 @@
+{
+  "name": "solidities",
+  "version": "1.0.0",
+  "main": "index.js",
+  "author": "Jason.Chen",
+  "license": "MIT",
+  "dependencies": {
+    "@openzeppelin/contracts": "^4.7.3"
+  }
+}

src/ERC1155/JZBG-GOODS.sol

@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "@openzeppelin/contracts/token/ERC1155/ERC1155.sol";
+import "@openzeppelin/contracts/token/ERC1155/extensions/ERC1155Burnable.sol";
+import "@openzeppelin/contracts/token/ERC1155/extensions/ERC1155Pausable.sol";
+import "@openzeppelin/contracts/token/ERC1155/extensions/ERC1155Supply.sol";
+import "@openzeppelin/contracts/token/ERC1155/extensions/ERC1155URIStorage.sol";
+import "@openzeppelin/contracts/access/Ownable.sol";
+import "@openzeppelin/contracts/utils/Strings.sol";
+import "../common/Symbolable.sol";
+
+contract JZBG1155 is
+    ERC1155,
+    ERC1155Burnable,
+    ERC1155Pausable,
+    ERC1155Supply,
+    ERC1155URIStorage,
+    Ownable,
+    Symbolable
+{
+    using Strings for uint256;
+
+    /**
+     * @dev Jing Zhong Bao Guo,JZBG,https://jzbg.org/
+     * 0x5B38Da6a701c568545dCfcB03FcB875f56beddC4,1,1234
+     * 0xAb8483F64d9C6d1EcF9b849Ae677dD3315835cb2,1,1234567890
+     * TRANSFER: 0xAb8483F64d9C6d1EcF9b849Ae677dD3315835cb2,0x5B38Da6a701c568545dCfcB03FcB875f56beddC4,1,5,0x
+     * mintBatch: 0xAb8483F64d9C6d1EcF9b849Ae677dD3315835cb2,[1,2,3,4],[100,2000,30000,400000]
+     * safeTransferToAddresses: 0xAb8483F64d9C6d1EcF9b849Ae677dD3315835cb2,[0x5B38Da6a701c568545dCfcB03FcB875f56beddC4,0x4B20993Bc481177ec7E8f571ceCaE8A9e22C02db,0x78731D3Ca6b7E34aC0F824c42a7cC18A495cabaB],1,200
+     */
+    constructor(
+        string memory name_,
+        string memory symbol_,
+        string memory uri_
+    ) Symbolable(name_, symbol_) ERC1155(uri_) {
+        ERC1155URIStorage._setBaseURI(uri_);
+    }
+
+    function setURI(uint256 tokenId, string memory tokenURI)
+        public
+        virtual
+        onlyOwner
+    {
+        _setURI(tokenId, tokenURI);
+    }
+
+    function setBaseURI(string memory baseURI) public virtual onlyOwner {
+        _setBaseURI(baseURI);
+    }
+
+    /**
+     * @dev 清空owner，重写了，防止误操作
+     */
+    function renounceOwnership() public virtual override onlyOwner {}
+
+    /**
+     * @dev 增发
+     */
+    function mint(
+        address to_,
+        uint256 tokenId_,
+        uint256 amount_,
+        string memory uri_
+    ) public virtual onlyOwner {
+        _mint(to_, tokenId_, amount_, "");
+        if (bytes(uri_).length > 0) {
+            _setURI(tokenId_, uri_);
+        }
+    }
+
+    /**
+     * @dev 批量增发
+     */
+    function bacthAddressMint(
+        address to_,
+        uint256[] memory tokenIds_,
+        uint256[] memory amounts_,
+        string[] memory uris_
+    ) public virtual onlyOwner {
+        require(
+            tokenIds_.length == amounts_.length,
+            "The tokenIds and Amounts are not match"
+        );
+
+        if (uris_.length > 0) {
+            require(
+                tokenIds_.length == uris_.length,
+                "The ids and uris are not match"
+            );
+        }
+
+        _mintBatch(to_, tokenIds_, amounts_, "");
+
+        if (uris_.length > 0) {
+            for (uint256 i = 0; i < tokenIds_.length; i++) {
+                _setURI(tokenIds_[i], uris_[i]);
+            }
+        }
+    }
+
+    /**
+     * @dev 批量给地址增发同一种代币
+     */
+    function batchAddressesMint(
+        address[] memory tos_,
+        uint256 tokenId_,
+        uint256 amount_,
+        string memory uri_
+    ) public virtual onlyOwner {
+        for (uint256 i = 0; i < tos_.length; i++) {
+            _mint(tos_[i], tokenId_, amount_, "");
+        }
+
+        if (bytes(uri_).length > 0) {
+            _setURI(tokenId_, uri_);
+        }
+    }
+
+    /**
+     * @dev See {IERC1155-safeBatchTransferFrom}.
+     */
+    function safeTransferToAddresses(
+        address from_,
+        address[] memory tos_,
+        uint256 tokenId_,
+        uint256 amount_
+    ) public virtual {
+        require(
+            from_ == _msgSender() || isApprovedForAll(from_, _msgSender()),
+            "ERC1155: caller is not token owner nor approved"
+        );
+
+        uint256 fromBalance = balanceOf(from_, tokenId_);
+        require(
+            fromBalance >= amount_ * tos_.length,
+            "ERC1155: insufficient balance for transfer"
+        );
+
+        for (uint256 i = 0; i < tos_.length; i++) {
+            _safeTransferFrom(from_, tos_[i], tokenId_, amount_, "");
+        }
+    }
+
+    /**
+     * @dev 暂停交易
+     */
+    function pause() public virtual whenNotPaused onlyOwner {
+        _pause();
+    }
+
+    /**
+     * @dev 恢复交易
+     */
+    function unpause() public virtual whenPaused onlyOwner {
+        _unpause();
+    }
+
+    function _beforeTokenTransfer(
+        address operator,
+        address from,
+        address to,
+        uint256[] memory ids,
+        uint256[] memory amounts,
+        bytes memory data
+    ) internal virtual override(ERC1155, ERC1155Supply, ERC1155Pausable) {
+        ERC1155._beforeTokenTransfer(operator, from, to, ids, amounts, data);
+        ERC1155Pausable._beforeTokenTransfer(
+            operator,
+            from,
+            to,
+            ids,
+            amounts,
+            data
+        );
+        ERC1155Supply._beforeTokenTransfer(
+            operator,
+            from,
+            to,
+            ids,
+            amounts,
+            data
+        );
+    }
+
+    function uri(uint256 tokenId)
+        public
+        view
+        virtual
+        override(ERC1155, ERC1155URIStorage)
+        returns (string memory)
+    {
+        return ERC1155URIStorage.uri(tokenId);
+    }
+}

src/ERC20/CZZX.sol

@@ -0,0 +1,754 @@
+// SPDX-License-Identifier: GPL-3.0
+
+pragma solidity ^0.8.0;
+
+abstract contract Context {
+    function _msgSender() internal view virtual returns (address) {
+        return msg.sender;
+    }
+
+    function _msgData() internal view virtual returns (bytes calldata) {
+        return msg.data;
+    }
+}
+
+interface IERC20 {
+    /**
+     * @dev Emitted when `value` tokens are moved from one account (`from`) to
+     * another (`to`).
+     *
+     * Note that `value` may be zero.
+     */
+    event Transfer(address indexed from, address indexed to, uint256 value);
+
+    /**
+     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
+     * a call to {approve}. `value` is the new allowance.
+     */
+    event Approval(
+        address indexed owner,
+        address indexed spender,
+        uint256 value
+    );
+
+    /**
+     * @dev Returns the amount of tokens in existence.
+     */
+    function totalSupply() external view returns (uint256);
+
+    /**
+     * @dev Returns the amount of tokens owned by `account`.
+     */
+    function balanceOf(address account) external view returns (uint256);
+
+    /**
+     * @dev Moves `amount` tokens from the caller's account to `to`.
+     *
+     * Returns a boolean value indicating whether the operation succeeded.
+     *
+     * Emits a {Transfer} event.
+     */
+    function transfer(address to, uint256 amount) external returns (bool);
+
+    /**
+     * @dev Returns the remaining number of tokens that `spender` will be
+     * allowed to spend on behalf of `owner` through {transferFrom}. This is
+     * zero by default.
+     *
+     * This value changes when {approve} or {transferFrom} are called.
+     */
+    function allowance(address owner, address spender)
+        external
+        view
+        returns (uint256);
+
+    /**
+     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
+     *
+     * Returns a boolean value indicating whether the operation succeeded.
+     *
+     * IMPORTANT: Beware that changing an allowance with this method brings the risk
+     * that someone may use both the old and the new allowance by unfortunate
+     * transaction ordering. One possible solution to mitigate this race
+     * condition is to first reduce the spender's allowance to 0 and set the
+     * desired value afterwards:
+     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
+     *
+     * Emits an {Approval} event.
+     */
+    function approve(address spender, uint256 amount) external returns (bool);
+
+    /**
+     * @dev Moves `amount` tokens from `from` to `to` using the
+     * allowance mechanism. `amount` is then deducted from the caller's
+     * allowance.
+     *
+     * Returns a boolean value indicating whether the operation succeeded.
+     *
+     * Emits a {Transfer} event.
+     */
+    function transferFrom(
+        address from,
+        address to,
+        uint256 amount
+    ) external returns (bool);
+}
+
+interface IERC20Metadata is IERC20 {
+    /**
+     * @dev Returns the name of the token.
+     */
+    function name() external view returns (string memory);
+
+    /**
+     * @dev Returns the symbol of the token.
+     */
+    function symbol() external view returns (string memory);
+
+    /**
+     * @dev Returns the decimals places of the token.
+     */
+    function decimals() external view returns (uint8);
+}
+
+library SafeMath {
+    /**
+     * @dev Returns the addition of two unsigned integers, with an overflow flag.
+     *
+     * _Available since v3.4._
+     */
+    function tryAdd(uint256 a, uint256 b)
+        internal
+        pure
+        returns (bool, uint256)
+    {
+        unchecked {
+            uint256 c = a + b;
+            if (c < a) return (false, 0);
+            return (true, c);
+        }
+    }
+
+    /**
+     * @dev Returns the subtraction of two unsigned integers, with an overflow flag.
+     *
+     * _Available since v3.4._
+     */
+    function trySub(uint256 a, uint256 b)
+        internal
+        pure
+        returns (bool, uint256)
+    {
+        unchecked {
+            if (b > a) return (false, 0);
+            return (true, a - b);
+        }
+    }
+
+    /**
+     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
+     *
+     * _Available since v3.4._
+     */
+    function tryMul(uint256 a, uint256 b)
+        internal
+        pure
+        returns (bool, uint256)
+    {
+        unchecked {
+            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
+            // benefit is lost if 'b' is also tested.
+            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
+            if (a == 0) return (true, 0);
+            uint256 c = a * b;
+            if (c / a != b) return (false, 0);
+            return (true, c);
+        }
+    }
+
+    /**
+     * @dev Returns the division of two unsigned integers, with a division by zero flag.
+     *
+     * _Available since v3.4._
+     */
+    function tryDiv(uint256 a, uint256 b)
+        internal
+        pure
+        returns (bool, uint256)
+    {
+        unchecked {
+            if (b == 0) return (false, 0);
+            return (true, a / b);
+        }
+    }
+
+    /**
+     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
+     *
+     * _Available since v3.4._
+     */
+    function tryMod(uint256 a, uint256 b)
+        internal
+        pure
+        returns (bool, uint256)
+    {
+        unchecked {
+            if (b == 0) return (false, 0);
+            return (true, a % b);
+        }
+    }
+
+    /**
+     * @dev Returns the addition of two unsigned integers, reverting on
+     * overflow.
+     *
+     * Counterpart to Solidity's `+` operator.
+     *
+     * Requirements:
+     *
+     * - Addition cannot overflow.
+     */
+    function add(uint256 a, uint256 b) internal pure returns (uint256) {
+        return a + b;
+    }
+
+    /**
+     * @dev Returns the subtraction of two unsigned integers, reverting on
+     * overflow (when the result is negative).
+     *
+     * Counterpart to Solidity's `-` operator.
+     *
+     * Requirements:
+     *
+     * - Subtraction cannot overflow.
+     */
+    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
+        return a - b;
+    }
+
+    /**
+     * @dev Returns the multiplication of two unsigned integers, reverting on
+     * overflow.
+     *
+     * Counterpart to Solidity's `*` operator.
+     *
+     * Requirements:
+     *
+     * - Multiplication cannot overflow.
+     */
+    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
+        return a * b;
+    }
+
+    /**
+     * @dev Returns the integer division of two unsigned integers, reverting on
+     * division by zero. The result is rounded towards zero.
+     *
+     * Counterpart to Solidity's `/` operator.
+     *
+     * Requirements:
+     *
+     * - The divisor cannot be zero.
+     */
+    function div(uint256 a, uint256 b) internal pure returns (uint256) {
+        return a / b;
+    }
+
+    /**
+     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
+     * reverting when dividing by zero.
+     *
+     * Counterpart to Solidity's `%` operator. This function uses a `revert`
+     * opcode (which leaves remaining gas untouched) while Solidity uses an
+     * invalid opcode to revert (consuming all remaining gas).
+     *
+     * Requirements:
+     *
+     * - The divisor cannot be zero.
+     */
+    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
+        return a % b;
+    }
+
+    /**
+     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
+     * overflow (when the result is negative).
+     *
+     * CAUTION: This function is deprecated because it requires allocating memory for the error
+     * message unnecessarily. For custom revert reasons use {trySub}.
+     *
+     * Counterpart to Solidity's `-` operator.
+     *
+     * Requirements:
+     *
+     * - Subtraction cannot overflow.
+     */
+    function sub(
+        uint256 a,
+        uint256 b,
+        string memory errorMessage
+    ) internal pure returns (uint256) {
+        unchecked {
+            require(b <= a, errorMessage);
+            return a - b;
+        }
+    }
+
+    /**
+     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
+     * division by zero. The result is rounded towards zero.
+     *
+     * Counterpart to Solidity's `/` operator. Note: this function uses a
+     * `revert` opcode (which leaves remaining gas untouched) while Solidity
+     * uses an invalid opcode to revert (consuming all remaining gas).
+     *
+     * Requirements:
+     *
+     * - The divisor cannot be zero.
+     */
+    function div(
+        uint256 a,
+        uint256 b,
+        string memory errorMessage
+    ) internal pure returns (uint256) {
+        unchecked {
+            require(b > 0, errorMessage);
+            return a / b;
+        }
+    }
+
+    /**
+     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
+     * reverting with custom message when dividing by zero.
+     *
+     * CAUTION: This function is deprecated because it requires allocating memory for the error
+     * message unnecessarily. For custom revert reasons use {tryMod}.
+     *
+     * Counterpart to Solidity's `%` operator. This function uses a `revert`
+     * opcode (which leaves remaining gas untouched) while Solidity uses an
+     * invalid opcode to revert (consuming all remaining gas).
+     *
+     * Requirements:
+     *
+     * - The divisor cannot be zero.
+     */
+    function mod(
+        uint256 a,
+        uint256 b,
+        string memory errorMessage
+    ) internal pure returns (uint256) {
+        unchecked {
+            require(b > 0, errorMessage);
+            return a % b;
+        }
+    }
+}
+
+contract ERC20 is Context, IERC20, IERC20Metadata {
+    mapping(address => uint256) private _balances;
+
+    mapping(address => mapping(address => uint256)) private _allowances;
+
+    uint256 private _totalSupply;
+
+    string private _name;
+    string private _symbol;
+
+    /**
+     * @dev Sets the values for {name} and {symbol}.
+     *
+     * The default value of {decimals} is 18. To select a different value for
+     * {decimals} you should overload it.
+     *
+     * All two of these values are immutable: they can only be set once during
+     * construction.
+     */
+    constructor(string memory name_, string memory symbol_) {
+        _name = name_;
+        _symbol = symbol_;
+    }
+
+    /**
+     * @dev Returns the name of the token.
+     */
+    function name() public view virtual override returns (string memory) {
+        return _name;
+    }
+
+    /**
+     * @dev Returns the symbol of the token, usually a shorter version of the
+     * name.
+     */
+    function symbol() public view virtual override returns (string memory) {
+        return _symbol;
+    }
+
+    /**
+     * @dev Returns the number of decimals used to get its user representation.
+     * For example, if `decimals` equals `2`, a balance of `505` tokens should
+     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
+     *
+     * Tokens usually opt for a value of 18, imitating the relationship between
+     * Ether and Wei. This is the value {ERC20} uses, unless this function is
+     * overridden;
+     *
+     * NOTE: This information is only used for _display_ purposes: it in
+     * no way affects any of the arithmetic of the contract, including
+     * {IERC20-balanceOf} and {IERC20-transfer}.
+     */
+    function decimals() public view virtual override returns (uint8) {
+        return 18;
+    }
+
+    /**
+     * @dev See {IERC20-totalSupply}.
+     */
+    function totalSupply() public view virtual override returns (uint256) {
+        return _totalSupply;
+    }
+
+    /**
+     * @dev See {IERC20-balanceOf}.
+     */
+    function balanceOf(address account)
+        public
+        view
+        virtual
+        override
+        returns (uint256)
+    {
+        return _balances[account];
+    }
+
+    /**
+     * @dev See {IERC20-transfer}.
+     *
+     * Requirements:
+     *
+     * - `to` cannot be the zero address.
+     * - the caller must have a balance of at least `amount`.
+     */
+    function transfer(address to, uint256 amount)
+        public
+        virtual
+        override
+        returns (bool)
+    {
+        address owner = _msgSender();
+        _transfer(owner, to, amount);
+        return true;
+    }
+
+    /**
+     * @dev See {IERC20-allowance}.
+     */
+    function allowance(address owner, address spender)
+        public
+        view
+        virtual
+        override
+        returns (uint256)
+    {
+        return _allowances[owner][spender];
+    }
+
+    /**
+     * @dev See {IERC20-approve}.
+     *
+     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
+     * `transferFrom`. This is semantically equivalent to an infinite approval.
+     *
+     * Requirements:
+     *
+     * - `spender` cannot be the zero address.
+     */
+    function approve(address spender, uint256 amount)
+        public
+        virtual
+        override
+        returns (bool)
+    {
+        address owner = _msgSender();
+        _approve(owner, spender, amount);
+        return true;
+    }
+
+    /**
+     * @dev See {IERC20-transferFrom}.
+     *
+     * Emits an {Approval} event indicating the updated allowance. This is not
+     * required by the EIP. See the note at the beginning of {ERC20}.
+     *
+     * NOTE: Does not update the allowance if the current allowance
+     * is the maximum `uint256`.
+     *
+     * Requirements:
+     *
+     * - `from` and `to` cannot be the zero address.
+     * - `from` must have a balance of at least `amount`.
+     * - the caller must have allowance for ``from``'s tokens of at least
+     * `amount`.
+     */
+    function transferFrom(
+        address from,
+        address to,
+        uint256 amount
+    ) public virtual override returns (bool) {
+        address spender = _msgSender();
+        _spendAllowance(from, spender, amount);
+        _transfer(from, to, amount);
+        return true;
+    }
+
+    /**
+     * @dev Atomically increases the allowance granted to `spender` by the caller.
+     *
+     * This is an alternative to {approve} that can be used as a mitigation for
+     * problems described in {IERC20-approve}.
+     *
+     * Emits an {Approval} event indicating the updated allowance.
+     *
+     * Requirements:
+     *
+     * - `spender` cannot be the zero address.
+     */
+    function increaseAllowance(address spender, uint256 addedValue)
+        public
+        virtual
+        returns (bool)
+    {
+        address owner = _msgSender();
+        _approve(owner, spender, allowance(owner, spender) + addedValue);
+        return true;
+    }
+
+    /**
+     * @dev Atomically decreases the allowance granted to `spender` by the caller.
+     *
+     * This is an alternative to {approve} that can be used as a mitigation for
+     * problems described in {IERC20-approve}.
+     *
+     * Emits an {Approval} event indicating the updated allowance.
+     *
+     * Requirements:
+     *
+     * - `spender` cannot be the zero address.
+     * - `spender` must have allowance for the caller of at least
+     * `subtractedValue`.
+     */
+    function decreaseAllowance(address spender, uint256 subtractedValue)
+        public
+        virtual
+        returns (bool)
+    {
+        address owner = _msgSender();
+        uint256 currentAllowance = allowance(owner, spender);
+        require(
+            currentAllowance >= subtractedValue,
+            "ERC20: decreased allowance below zero"
+        );
+        unchecked {
+            _approve(owner, spender, currentAllowance - subtractedValue);
+        }
+
+        return true;
+    }
+
+    /**
+     * @dev Moves `amount` of tokens from `from` to `to`.
+     *
+     * This internal function is equivalent to {transfer}, and can be used to
+     * e.g. implement automatic token fees, slashing mechanisms, etc.
+     *
+     * Emits a {Transfer} event.
+     *
+     * Requirements:
+     *
+     * - `from` cannot be the zero address.
+     * - `to` cannot be the zero address.
+     * - `from` must have a balance of at least `amount`.
+     */
+    function _transfer(
+        address from,
+        address to,
+        uint256 amount
+    ) internal virtual {
+        require(from != address(0), "ERC20: transfer from the zero address");
+        require(to != address(0), "ERC20: transfer to the zero address");
+
+        _beforeTokenTransfer(from, to, amount);
+
+        uint256 fromBalance = _balances[from];
+        require(
+            fromBalance >= amount,
+            "ERC20: transfer amount exceeds balance"
+        );
+        unchecked {
+            _balances[from] = fromBalance - amount;
+            // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
+            // decrementing then incrementing.
+            _balances[to] += amount;
+        }
+
+        emit Transfer(from, to, amount);
+
+        _afterTokenTransfer(from, to, amount);
+    }
+
+    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
+     * the total supply.
+     *
+     * Emits a {Transfer} event with `from` set to the zero address.
+     *
+     * Requirements:
+     *
+     * - `account` cannot be the zero address.
+     */
+    function _mint(address account, uint256 amount) internal virtual {
+        require(account != address(0), "ERC20: mint to the zero address");
+
+        _beforeTokenTransfer(address(0), account, amount);
+
+        _totalSupply += amount;
+        unchecked {
+            // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
+            _balances[account] += amount;
+        }
+        emit Transfer(address(0), account, amount);
+
+        _afterTokenTransfer(address(0), account, amount);
+    }
+
+    /**
+     * @dev Destroys `amount` tokens from `account`, reducing the
+     * total supply.
+     *
+     * Emits a {Transfer} event with `to` set to the zero address.
+     *
+     * Requirements:
+     *
+     * - `account` cannot be the zero address.
+     * - `account` must have at least `amount` tokens.
+     */
+    function _burn(address account, uint256 amount) internal virtual {
+        require(account != address(0), "ERC20: burn from the zero address");
+
+        _beforeTokenTransfer(account, address(0), amount);
+
+        uint256 accountBalance = _balances[account];
+        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
+        unchecked {
+            _balances[account] = accountBalance - amount;
+            // Overflow not possible: amount <= accountBalance <= totalSupply.
+            _totalSupply -= amount;
+        }
+
+        emit Transfer(account, address(0), amount);
+
+        _afterTokenTransfer(account, address(0), amount);
+    }
+
+    /**
+     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
+     *
+     * This internal function is equivalent to `approve`, and can be used to
+     * e.g. set automatic allowances for certain subsystems, etc.
+     *
+     * Emits an {Approval} event.
+     *
+     * Requirements:
+     *
+     * - `owner` cannot be the zero address.
+     * - `spender` cannot be the zero address.
+     */
+    function _approve(
+        address owner,
+        address spender,
+        uint256 amount
+    ) internal virtual {
+        require(owner != address(0), "ERC20: approve from the zero address");
+        require(spender != address(0), "ERC20: approve to the zero address");
+
+        _allowances[owner][spender] = amount;
+        emit Approval(owner, spender, amount);
+    }
+
+    /**
+     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
+     *
+     * Does not update the allowance amount in case of infinite allowance.
+     * Revert if not enough allowance is available.
+     *
+     * Might emit an {Approval} event.
+     */
+    function _spendAllowance(
+        address owner,
+        address spender,
+        uint256 amount
+    ) internal virtual {
+        uint256 currentAllowance = allowance(owner, spender);
+        if (currentAllowance != type(uint256).max) {
+            require(
+                currentAllowance >= amount,
+                "ERC20: insufficient allowance"
+            );
+            unchecked {
+                _approve(owner, spender, currentAllowance - amount);
+            }
+        }
+    }
+
+    /**
+     * @dev Hook that is called before any transfer of tokens. This includes
+     * minting and burning.
+     *
+     * Calling conditions:
+     *
+     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
+     * will be transferred to `to`.
+     * - when `from` is zero, `amount` tokens will be minted for `to`.
+     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
+     * - `from` and `to` are never both zero.
+     *
+     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
+     */
+    function _beforeTokenTransfer(
+        address from,
+        address to,
+        uint256 amount
+    ) internal virtual {}
+
+    /**
+     * @dev Hook that is called after any transfer of tokens. This includes
+     * minting and burning.
+     *
+     * Calling conditions:
+     *
+     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
+     * has been transferred to `to`.
+     * - when `from` is zero, `amount` tokens have been minted for `to`.
+     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
+     * - `from` and `to` are never both zero.
+     *
+     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
+     */
+    function _afterTokenTransfer(
+        address from,
+        address to,
+        uint256 amount
+    ) internal virtual {}
+}
+
+contract CZZX is ERC20 {
+    constructor(
+        string memory name_,
+        string memory symbol_,
+        uint256 totalSupply_
+    ) ERC20(name_, symbol_) {
+        _mint(msg.sender, totalSupply_);
+    }
+
+    function decimals() public view virtual override returns (uint8) {
+        return 8;
+    }
+}

src/common/Symbolable.sol

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+abstract contract Symbolable {
+    string private _name;
+
+    string private _symbol;
+
+    constructor(string memory name_, string memory symbol_) {
+        _name = name_;
+        _symbol = symbol_;
+    }
+
+    function name() public view virtual returns (string memory) {
+        return _name;
+    }
+
+    function symbol() public view virtual returns (string memory) {
+        return _symbol;
+    }
+}

yarn.lock

@@ -0,0 +1,8 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+"@openzeppelin/contracts@^4.7.3":
+  version "4.7.3"
+  resolved "https://registry.npmmirror.com/@openzeppelin/contracts/-/contracts-4.7.3.tgz#939534757a81f8d69cc854c7692805684ff3111e"
+  integrity sha512-dGRS0agJzu8ybo44pCIf3xBaPQN/65AIXNgK8+4gzKd5kbvlqyxryUYVLJv7fK98Seyd2hDZzVEHSWAh0Bt1Yw==