solidity/test/libsolidity/semanticTests/viaYul/erc20.sol
2020-01-11 23:11:00 +01:00

104 lines
3.7 KiB
Solidity

pragma solidity >=0.4.0 <0.8.0;
contract ERC20 {
event Transfer(address indexed from, address indexed to, uint256 value);
event Approval(address indexed owner, address indexed spender, uint256 value);
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowances;
uint256 private _totalSupply;
constructor() public {
_mint(msg.sender, 20);
}
function totalSupply() public view returns (uint256) {
return _totalSupply;
}
function balanceOf(address owner) public view returns (uint256) {
return _balances[owner];
}
function allowance(address owner, address spender) public view returns (uint256) {
return _allowances[owner][spender];
}
function transfer(address to, uint256 value) public returns (bool) {
_transfer(msg.sender, to, value);
return true;
}
function approve(address spender, uint256 value) public returns (bool) {
_approve(msg.sender, spender, value);
return true;
}
function transferFrom(address from, address to, uint256 value) public returns (bool) {
_transfer(from, to, value);
// The subtraction here will revert on overflow.
_approve(from, msg.sender, _allowances[from][msg.sender] - value);
return true;
}
function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
// The addition here will revert on overflow.
_approve(msg.sender, spender, _allowances[msg.sender][spender] + addedValue);
return true;
}
function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
// The subtraction here will revert on overflow.
_approve(msg.sender, spender, _allowances[msg.sender][spender] - subtractedValue);
return true;
}
function _transfer(address from, address to, uint256 value) internal {
require(to != address(0), "ERC20: transfer to the zero address");
// The subtraction and addition here will revert on overflow.
_balances[from] = _balances[from] - value;
_balances[to] = _balances[to] + value;
emit Transfer(from, to, value);
}
function _mint(address account, uint256 value) internal {
require(account != address(0), "ERC20: mint to the zero address");
// The additions here will revert on overflow.
_totalSupply = _totalSupply + value;
_balances[account] = _balances[account] + value;
emit Transfer(address(0), account, value);
}
function _burn(address account, uint256 value) internal {
require(account != address(0), "ERC20: burn from the zero address");
// The subtractions here will revert on overflow.
_totalSupply = _totalSupply - value;
_balances[account] = _balances[account] - value;
emit Transfer(account, address(0), value);
}
function _approve(address owner, address spender, uint256 value) internal {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = value;
emit Approval(owner, spender, value);
}
function _burnFrom(address account, uint256 value) internal {
_burn(account, value);
_approve(account, msg.sender, _allowances[account][msg.sender] - value);
}
}
// ====
// compileViaYul: true
// ----
// totalSupply() -> 20
// transfer(address,uint256): 2, 5 -> true
// decreaseAllowance(address,uint256): 2, 0 -> true
// decreaseAllowance(address,uint256): 2, 1 -> FAILURE
// transfer(address,uint256): 2, 14 -> true
// transfer(address,uint256): 2, 2 -> FAILURE