60 lines
2.1 KiB
Solidity
60 lines
2.1 KiB
Solidity
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// SPDX-License-Identifier: UNLICENSED
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pragma solidity =0.7.6;
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import '../interfaces/IERC20Minimal.sol';
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contract TestERC20 is IERC20Minimal {
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mapping(address => uint256) public override balanceOf;
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mapping(address => mapping(address => uint256)) public override allowance;
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constructor(uint256 amountToMint) {
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mint(msg.sender, amountToMint);
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}
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function mint(address to, uint256 amount) public {
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uint256 balanceNext = balanceOf[to] + amount;
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require(balanceNext >= amount, 'overflow balance');
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balanceOf[to] = balanceNext;
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}
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function transfer(address recipient, uint256 amount) external override returns (bool) {
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uint256 balanceBefore = balanceOf[msg.sender];
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require(balanceBefore >= amount, 'insufficient balance');
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balanceOf[msg.sender] = balanceBefore - amount;
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uint256 balanceRecipient = balanceOf[recipient];
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require(balanceRecipient + amount >= balanceRecipient, 'recipient balance overflow');
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balanceOf[recipient] = balanceRecipient + amount;
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emit Transfer(msg.sender, recipient, amount);
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return true;
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}
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function approve(address spender, uint256 amount) external override returns (bool) {
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allowance[msg.sender][spender] = amount;
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emit Approval(msg.sender, spender, amount);
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return true;
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}
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function transferFrom(
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address sender,
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address recipient,
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uint256 amount
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) external override returns (bool) {
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uint256 allowanceBefore = allowance[sender][msg.sender];
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require(allowanceBefore >= amount, 'allowance insufficient');
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allowance[sender][msg.sender] = allowanceBefore - amount;
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uint256 balanceRecipient = balanceOf[recipient];
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require(balanceRecipient + amount >= balanceRecipient, 'overflow balance recipient');
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balanceOf[recipient] = balanceRecipient + amount;
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uint256 balanceSender = balanceOf[sender];
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require(balanceSender >= amount, 'underflow balance sender');
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balanceOf[sender] = balanceSender - amount;
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emit Transfer(sender, recipient, amount);
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return true;
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}
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}
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