// SPDX-License-Identifier: MIT
/**
* @title CustomizedERC20
* @author github.com/codermaybe
* @dev CustomizedERC20 is a customized ERC20 token with a few additional features.
* @dev 本合约仅用于学习和研究。所有复现均按照eip20标准。详见：https://github.com/ethereum/ercs/blob/master/ERCS/erc-20.md
* @dev 自行复现的erc20各项功能。
* @dev V1版本特性：1.除复现各标准函数外增加 _contractOwner字段，增加erc20未定义但常用方法 mint()、burn()。暂无增加角色地址池，特殊操作均有合约拥有者控制。
*/
pragma solidity ^0.8.28;
contract CE20V1 {
address private _contractOwner; //自行设定，为合约拥有者
string private _name;
string private _symbol;
uint8 private _decimals;
uint256 private _totalSupply;
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) _allowances;
event Transfer(address indexed _from, address indexed _to, uint256 _value);
event Approval(
address indexed _owner,
address indexed _spender,
uint256 _value
);
constructor(
string memory name,
string memory symbol,
uint8 decimals,
uint256 totalSupply
) {
_contractOwner = msg.sender;
_name = name;
_symbol = symbol;
_decimals = decimals;
_totalSupply = totalSupply;
_balances[msg.sender] = totalSupply;
emit Transfer(address(0), msg.sender, totalSupply);
}
/*
name
Returns the name of the token - e.g. "MyToken".
OPTIONAL - This method can be used to improve usability, but interfaces and other contracts MUST NOT expect these values to be present. */
function name() public view returns (string memory) {
return _name;
}
/*
symbol
Returns the symbol of the token. E.g. "HIX".
OPTIONAL - This method can be used to improve usability, but interfaces and other contracts MUST NOT expect these values to be present. */
function symbol() public view returns (string memory) {
return _symbol;
}
/*
decimals
Returns the number of decimals the token uses - e.g. 8, means to divide the token amount by 100000000 to get its user representation.
OPTIONAL - This method can be used to improve usability, but interfaces and other contracts MUST NOT expect these values to be present.*/
function decimals() public view returns (uint8) {
return _decimals;
}
/*
totalSupply
Returns the total token supply.*/
function totalSupply() public view returns (uint256) {
return _totalSupply;
}
/*
balanceOf
Returns the account balance of another account with address _owner. */
function balanceOf(address _owner) public view returns (uint256) {
return _balances[_owner];
}
/*
transfer
Transfers _value amount of tokens to address _to, and MUST fire the Transfer event.
The function SHOULD throw if the message caller's account balance does not have enough tokens to spend.
Note Transfers of 0 values MUST be treated as normal transfers and fire the Transfer event. */
function transfer(address _to, uint256 _value) public returns (bool) {
require(_to != address(0), unicode"不可向0地址转账");
require(_balances[msg.sender] >= _value, unicode"余额不足");
require(_balances[_to] + _value > _balances[_to], unicode"数值溢出");
_balances[msg.sender] -= _value;
_balances[_to] += _value;
emit Transfer(msg.sender, _to, _value);
return true;
}
/*
transferFrom
Transfers _value amount of tokens from address _from to address _to, and MUST fire the Transfer event.
The transferFrom method is used for a withdraw workflow, allowing contracts to transfer tokens on your behalf.
This can be used for example to allow a contract to transfer tokens on your behalf and/or to charge fees in sub-currencies.
The function SHOULD throw unless the _from account has deliberately authorized the sender of the message via some mechanism.
Note Transfers of 0 values MUST be treated as normal transfers and fire the Transfer event. */
function transferFrom(
address _from,
address _to,
uint256 _value
) public returns (bool success) {
require(_to != address(0), unicode"不可向0地址转账");
require(
_allowances[_from][msg.sender] >= _value,
unicode"授权额度不足"
);
require(_balances[_from] >= _value, unicode"转账账户额度不足");
require(_balances[_to] + _value > _balances[_to], unicode"余额溢出");
_allowances[_from][msg.sender] -= _value;
_balances[_from] -= _value;
_balances[_to] += _value;
emit Transfer(_from, _to, _value);
return true;
}
/*
approve
Allows _spender to withdraw from your account multiple times, up to the _value amount.
If this function is called again it overwrites the current allowance with _value.
NOTE: To prevent attack vectors like the one described here and discussed here, clients SHOULD make sure to create user interfaces in such a way that they set the allowance first to 0 before setting it to another value for the same spender.
THOUGH The contract itself shouldn't enforce it, to allow backwards compatibility with contracts deployed before */
function approve(
//此版本未解决重入攻击,安全版本可检查CE20V1_openzepplin.sol
address _spender,
uint256 _value
) public returns (bool success) {
require(
_allowances[msg.sender][_spender] + _value >
_allowances[msg.sender][_spender],
unicode"授权额度溢出"
);
require(_spender != address(0), unicode"转账地址为0");
_allowances[msg.sender][_spender] = _value;
emit Approval(msg.sender, _spender, _value);
return true;
}
/*
allowance
Returns the amount which _spender is still allowed to withdraw from _owner.*/
function allowance(
address _owner,
address _spender
) public view returns (uint256 remaining) {
return _allowances[_owner][_spender];
}
/*自定义方法实现，使用mint派生代币 */
event Mint(address _to, uint256 _value);
function mint(address _to, uint256 _value) public {
require(
msg.sender == _contractOwner,
unicode"非合约拥有者无法派生代币"
);
require(_balances[_to] + _value > _balances[_to], unicode"余额溢出");
require(_totalSupply + _value > _totalSupply, unicode"总代币量将溢出");
_balances[_to] += _value;
_totalSupply += _value;
emit Transfer(address(0), _to, _value);
emit Mint(_to, _value);
}
/*自定义方法实现，使用burn燃烧代币 */
event Burn(address _from, uint256 _value);
function burn(address _from, uint256 _value) public {
require(
msg.sender == _contractOwner,
unicode"非合约拥有者无法派生代币"
);
require(
_balances[_from] >= _value,
unicode"检查燃烧的代币数量，超过用户余额"
);
_balances[_from] -= _value;
_totalSupply -= _value;
emit Burn(_from, _value);
}
}