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Bytes32Metadata.sol
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Bytes32Metadata.sol
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// Copyright (C) 2017, 2018, 2019, 2020 dbrock, rain, mrchico, d-xo
// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity >=0.6.12;
contract Math {
// --- Math ---
function add(uint x, uint y) internal pure returns (uint z) {
require((z = x + y) >= x);
}
function sub(uint x, uint y) internal pure returns (uint z) {
require((z = x - y) <= x);
}
}
contract ERC20 is Math {
// --- ERC20 Data ---
bytes32 public constant name = "Token";
bytes32 public constant symbol = "TKN";
uint8 public constant decimals = 18;
uint256 public totalSupply;
mapping (address => uint) public balanceOf;
mapping (address => mapping (address => uint)) public allowance;
event Approval(address indexed src, address indexed guy, uint wad);
event Transfer(address indexed src, address indexed dst, uint wad);
// --- Init ---
constructor(uint _totalSupply) public {
totalSupply = _totalSupply;
balanceOf[msg.sender] = _totalSupply;
emit Transfer(address(0), msg.sender, _totalSupply);
}
// --- Token ---
function transfer(address dst, uint wad) virtual public returns (bool) {
return transferFrom(msg.sender, dst, wad);
}
function transferFrom(address src, address dst, uint wad) virtual public returns (bool) {
require(balanceOf[src] >= wad, "insufficient-balance");
if (src != msg.sender && allowance[src][msg.sender] != type(uint).max) {
require(allowance[src][msg.sender] >= wad, "insufficient-allowance");
allowance[src][msg.sender] = sub(allowance[src][msg.sender], wad);
}
balanceOf[src] = sub(balanceOf[src], wad);
balanceOf[dst] = add(balanceOf[dst], wad);
emit Transfer(src, dst, wad);
return true;
}
function approve(address usr, uint wad) virtual public returns (bool) {
allowance[msg.sender][usr] = wad;
emit Approval(msg.sender, usr, wad);
return true;
}
}