127 lines
4.4 KiB
Solidity
127 lines
4.4 KiB
Solidity
pragma solidity 0.5.12;
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import "../interfaces/IERC20.sol";
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import "../libraries/SafeMath256.sol";
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contract ERC20 is IERC20 {
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using SafeMath256 for uint256;
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// ERC-20 data
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string public name;
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string public symbol;
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uint8 public decimals;
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uint256 public totalSupply;
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mapping (address => uint256) public balanceOf;
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mapping (address => mapping (address => uint256)) public allowance;
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// ERC-721 data
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bytes32 public DOMAIN_SEPARATOR;
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// keccak256("Approve(address owner,address spender,uint256 value,uint256 nonce,uint256 expiration)");
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bytes32 public constant APPROVE_TYPEHASH = hex'25a0822e8c2ed7ff64a57c55df37ff176282195b9e0c9bb770ed24a300c89762';
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mapping (address => uint256) public nonces;
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event Transfer(address indexed from, address indexed to, uint256 value);
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event Approval(address indexed owner, address indexed spender, uint256 value);
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function MOCK_getChainId() private pure returns (uint256) {
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return 1;
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}
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constructor(string memory _name, string memory _symbol, uint8 _decimals, uint256 _totalSupply) public {
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name = _name;
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symbol = _symbol;
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decimals = _decimals;
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if (_totalSupply > 0) mint(msg.sender, _totalSupply);
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DOMAIN_SEPARATOR = keccak256(abi.encode(
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keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),
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keccak256(bytes(name)),
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keccak256(bytes("1")),
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MOCK_getChainId(),
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address(this)
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));
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}
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function mint(address to, uint256 value) internal {
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totalSupply = totalSupply.add(value);
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balanceOf[to] = balanceOf[to].add(value);
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emit Transfer(address(0), to, value);
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}
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function _burn(address from, uint256 value) internal {
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balanceOf[from] = balanceOf[from].sub(value);
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totalSupply = totalSupply.sub(value);
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emit Transfer(from, address(0), value);
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}
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function _transfer(address from, address to, uint256 value) private {
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balanceOf[from] = balanceOf[from].sub(value);
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balanceOf[to] = balanceOf[to].add(value);
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emit Transfer(from, to, value);
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}
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function _approve(address owner, address spender, uint256 value) private {
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allowance[owner][spender] = value;
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emit Approval(owner, spender, value);
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}
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function transfer(address to, uint256 value) external returns (bool) {
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_transfer(msg.sender, to, value);
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return true;
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}
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function burn(uint256 value) external {
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_burn(msg.sender, value);
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}
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function approve(address spender, uint256 value) external returns (bool) {
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_approve(msg.sender, spender, value);
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return true;
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}
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function approveMeta(
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address owner, address spender, uint256 value, uint256 nonce, uint256 expiration, uint8 v, bytes32 r, bytes32 s
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)
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external
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{
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require(nonce == nonces[owner]++, "ERC20: INVALID_NONCE");
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require(expiration > block.timestamp, "ERC20: EXPIRED_SIGNATURE");
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require(v == 27 || v == 28, "ECDSA: INVALID_V");
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require(uint256(s) <= 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0, "ECDSA: INVALID_S");
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bytes32 digest = keccak256(abi.encodePacked(
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hex'19',
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hex'01',
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DOMAIN_SEPARATOR,
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keccak256(abi.encode(
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APPROVE_TYPEHASH, owner, spender, value, nonce, expiration
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))
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));
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address recoveredAddress = ecrecover(digest, v, r, s);
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if (recoveredAddress != owner) {
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recoveredAddress = ecrecover(
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keccak256(abi.encodePacked(hex"19", "Ethereum Signed Message:", hex"32", digest)), v, r, s
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);
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}
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require(recoveredAddress != address(0), "ERC20: INVALID_RECOVERED_ADDRESS");
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require(recoveredAddress == owner, "ERC20: INVALID_SIGNATURE");
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_approve(owner, spender, value);
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}
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function transferFrom(address from, address to, uint256 value) external returns (bool) {
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if (allowance[from][msg.sender] != uint256(-1)) {
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allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
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}
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_transfer(from, to, value);
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return true;
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}
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function burnFrom(address from, uint256 value) external {
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if (allowance[from][msg.sender] != uint256(-1)) {
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allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
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}
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_burn(from, value);
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}
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}
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